Meniscal Root Tears: Current Concepts

Robinson JR, Jermin PJ

Volume 1 | Issue 2 | Aug – Nov 2016 | Page 35-46.


Author: Robinson JR[1], Jermin PJ[1].

[1] Avon Orthopaedic Centre Bristol, UK.

Address of Correspondence

Mr James Robinson, MB BS, MRCS, FRCS(Orth) MS
Avon Orthopaedic Centre, Bristol, UK
Email: info@KneeSpecialists.co.uk


Abstract

The menisci provide tibio-femoral joint congruity, stabilisation, shock absorption and proprioception. These functions are reliant on firm attachment to the tibial plateau at the meniscal roots. Meniscal root tears result in similar biomechanical consequences to total meniscectomy, but they remain easy to miss clinically and radiological evaluation may be unreliable. Different repair techniques are becoming more reproducible and laboratory studies have shown that the load bearing function of the menisci may, following adequate repair, be returned to approximate that of the intact knee. Whilst techniques continue to evolve, a lengthy period of protective post-operative rehabilitation remains necessary. It is hypothesized that restoration of the ability of the meniscus to dissipate load through the distribution of hoop stresses is projective of adjacent hyaline cartilage and the development of degenerate joint disease. subsequent progressive joint failure that may occur if they are left untreated.
Keywords: Meniscal Root Tear, Meniscal repair.


Introduction

The vital role meniscal integrity plays in the function of a healthy knee is well understood. As a result surgical treatment of meniscal tears has progressed. Previously, open total meniscectomy was performed for meniscal tears, however, the 132 fold increase in the rate of knee replacement that resulted condemned the technique to the annals of history (1). The treatment of meniscal tears now emphasises meniscal preservation when possible, with studies showing a reduction in osteoarthritis following meniscal repair as compared to tear resection (2). It has been demonstrated that tears of the meniscal root attachments de-function the effected meniscus and result in similar biomechanical consequences to total meniscectomy (3). Whilst the significance of meniscal root tears has long been recognised, it is only in the last decade that surgical techniques have evolved to allow the routine management of these lesions, aimed at improving symptoms and avoiding subsequent progressive joint failure that may occur if they are left untreated.

Meniscal Anatomy & Function
The menisci are 2 semi-lunar, fibrocartilage structures that surround the weight bearing surface of the medial and lateral tibial plateau (Fig. 1). They are wedge-shaped in cross section and crescent shaped in the axial plane. They are composed of 3 segments: an anterior horn/root, a body, and a posterior horn/root.(4,5). The medial meniscus is an asymmetric shaped structure, firmly attached to the joint capsule at its periphery (with, for example, the deep medial collateral ligament having both menisco-femoral and menisco-tibial fibres), thus rendering it relatively immobile and more prone to injury. The lateral meniscus is a much more symmetrical, incomplete O-shape and is less firmly attached making it a much more mobile structure to accommodate the increase in antero-posterior translation that occurs in the lateral compartment (during knee flexion, the lateral meniscus moves posteriorly by approximately 19mm, compared to only 4 mm for the medial meniscus (6)). Although the volumes of both menisci may be relatively similar, the lateral meniscus covers a significantly larger area of the tibial plateau than the medial meniscus (59% +/-6.8% vs 50% +/-5.5%) (7). The superior surfaces of both menisci are concave and thus congruent with the convex femoral articulation. The inferior surfaces are relatively flat, allowing them to effectively articulate with the tibial plateau (8,9).  Each meniscus is composed of an interlacing network of collagen fibres, proteoglycans and glycoproteins. They are composed of approximately 75% water, 20% type I collagen, and 5% of other substances including proteoglycans, elastin and type II collagen (10,11). In a study examining bovine menisci, Andrews et al. (12) found that the ultra-stucture of the meniscus transitioned from highly aligned, longitudinally orientated collagenous fibres in the outer rim to a woven, less aligned structure in the inner meniscus. They found that the outer meniscus closely resembled a ligamentous structure, whereas the inner meniscus more closely resembled hyaline cartilage. The role of the menisci is to provide tibio-femoral joint congruity, stabilisation, shock absorption and proprioception (9). They are essential for joint preservation (1,2). As the knee is loaded, joint compression acts to extrude the menisci in a radial direction towards the periphery of the joint. “Hoop stress” in the circumferential collagen bundles resist this meniscal extrusion (5,9,10,11). Two types of fascicle organisation are seen – braided and woven (12). Braided structures result in increased stiffness with increased deformation owing to increasing friction. This organisation is well suited to the circumferential hoop stresses that the meniscus is exposed to during loading. The woven structure is commonly used to withstand compressive loads; it converts compressive forces into tensile forces. The distribution of hoop stresses by the circumferential fibres helps to transmit even axial loads across the joint surfaces and approximately 50-70% of the total weight transmitted through either compartment is transmitted through each individual meniscus (13). This dissipation of load is protective of the adjacent hyaline cartilage, but is completely reliant on firm attachment of the menisci to the tibial plateau. The anterior and posterior horns of each meniscus are securely anchored to the tibial inter-condylar region by strong ligamentous-like root attachments. The anterior root attachments have relatively simple, planar insertions into the tibial plateau while the posterior roots have complex 3 dimensional insertions. (9,12,14) Knowledge of the anatomy of the meniscal root attachments is essential when considering repair as anatomic root repairs restore cartilage contact areas and minimise peak cartilage contact pressures better than non-anatomic root repair (15). The meniscal roots have three parts: the ligamentous mid-substance (root ligament), the transitional zone between the root ligament and meniscal body, and the bony insertion of the root ligament at the tibial plateau. (16) The transitional zone between the root ligament and the meniscus is considered to be the weakest link of the meniscus root (16) and this may explain the common finding of radial tears in the position particularly in degenerate menisci. The roots are very well vascularised, comparable to the red-red zone of the meniscus(16).

Medial Meniscus Anterior Root Attachment
The anatomy of the anterior medial meniscus root attachment is variable with 4 different types described by Berlet & Fowler (17). In 59% of knees the meniscus attached to the flat portion of the intercondylar region of the tibial plateau (Type 1). In 24% of knees the meniscus attached on the downward slope of the medial articular plateau towards the anterior intercondylar area (Type 2). In 15% of knees the root attached on the anterior slope of the medial tibial plateau (Type 3). In 3% the meniscus was only anchored by the peripheral coronary ligament with no direct attachment to the tibial plateau (Type 4). The anterior horn root attachment was associated with the fibres of anteromedial bundle of the ACL in 59% of knees. The anterior intermeniscal ligament (AIML) has been found to connect the anterior horns of both menisci in around 46% of knees although in 26% of knees it has been shown to run from the anterior horn of the medial meniscus to the lateral aspect of the joint capsule, anterior to the lateral meniscus. The significance of the intermeniscal ligament is unclear (18). Poh et al. (19) sectioned the AIML and found no change in the tibio-femoral contact mechanics. The authors concluded that the anterior root attachments result in the menisci distributing loads independently of one-another. In a separate study, however, Paci et al (20) sectioned the AIML and did notice significantly raised contact pressures within the medial compartment of the knee. As its role remains uncertain, it would seem reasonable to preserve and protect it during surgery if possible.

Medial Meniscus Posterior Root Attachment
Johannsen et al. (21) reported that position of the medial meniscus posterior horn root attachment was a mean distance of 3.5mm lateral to the medial tibial plateau articular cartilage inflection point and 8.2mm anterior to the most superior position of the PCL attachment site and a mean distance of 9.6mm posterior and 0.7mm lateral to the apex of the medial tibial eminence. Adjacent to the attachment of the posterior root are what some surgeons term the “shiny white fibres” (Fig. 2). These are easily recognisable and appear distinct to the root attachment although are continuous with the main posterior root attachment. Whilst not part of the central root attachment, it has been demonstrated that these supplementary ‘shiny white’ fibres significantly contribute to the biomechanical properties of the native meniscal root(16).

figure-1-and-2

Lateral Meniscal Anterior Root Attachment
This attaches just anterior to the lateral tibial eminence and and is intimately related to the tibial attachment of the ACL (Fig. 3a) . Zantop (22) et al reported that the centre of the anteromedial (AM) bundle of the ACL was, on average, 5.2mm medial and 2.7mm posterior to the lateral anterior root; while the posterolateral (PL) bundle was 11.2mm posterior and 4.1mm medial to the anterior root. Various studies have noted that the anterior horn of the lateral meniscus attaches to the ACL in all knees, sharing approximately 60% of their attachment sites (9,22,23,24,25). The lateral meniscal anterior root attachment is smaller than the medial meniscal anterior root, with average footprints of 44.5 mm2 and 93 mm2 respectively. The proximity of the lateral meniscus anterior root attachment to the ACL tibial attachment means that an ACL reconstruction tunnel placed postero-lateral in the ACL tibial attachment site may significantly weaken or disrupt the LM anterior root attachment (15).

Lateral Meniscal Posterior Root Attachment
The lateral meniscus posterior root attachment is posteromedial to the lateral tibial eminence apex, medial to the lateral articular cartilage edge, anterior to the PCL tibial attachment and anterolateral to the medial meniscus posterior root attachment. (9,25,26). Johannsen et al (21) also reported the centre of the lateral meniscal posterior root to be an area 4.3mm medial and 1.5mm posterior to the lateral tibial eminence (Fig. 3b) . Three different attachment patterns have been described (16). In 76% of cases, two insertion sites were found with the predominant component attaching to the intertubercular area with anterior extension into the medial tubercle and the minor component attaching to the posterior slope of the lateral tibial tubercle. In the remaining 24%, there was a solitary insertion site to either the inter tubercular area or the posterior slope of the lateral tubercle.

figure-3a-and-3b

Pathology & Epidemiology
The principle mechanical function of the menisci is to convert compressive loads into hoop stresses and relies on their firm attachment to the tibial plateau. Thus, when the meniscus root is torn, there is no restraint to the peripheral distortion of the menisci and meniscal extrusion occurs. The biomechanical consequences are of a decreased contact surface between the tibia and femur and supra-physiological cartilage contact pressures, analogous to a total meniscectomy (3) (Fig. 4). In a normal knee, peak articular cartilage contact pressures are on average, 3841 kPa. In the context of a medial meniscal posterior root tear, this can rise to 5084 kPa. The contact area falls from an average of 594mm2 in the normal knee to 474mm2 when there is a tear of the medial meniscal posterior root (27). It has been demonstrated that contact pressures and contact areas may be normalised following meniscus root repair. (3,28,29,30) The sequence of joint failure is thought to be: a root tear occurs, this results in greater meniscal displacement and gap formation at the root avulsion site when compressive loads are placed across the knee. Over time the meniscus extrudes as a result of unopposed radial forces. This leads to a combination of altered knee biomechanics and significant increases in articular cartilage contact pressures within that compartment resulting in degeneration and osteoarthritis (31).

figure-4

Anterior Meniscal Root Tears
Tears of the anterior roots are uncommon (11,32,33,34,35,36) but importantly, the anterior root attachment may be disrupted or weakened by iatrogenic injury (misplaced anterior cruciate ligament reconstruction tunnels and intra medullary tibial nailing entry sites being examples (15,37)). Medial Meniscal Posterior Root Tears. It is estimated that injury to the medial meniscus posterior root attachment may be present in 10-21% of arthroscopic meniscal repairs or meniscectomies (38,39,40). The true incidence may be higher owing to the limitations of current MRI to diagnose these tears. In addition the root attachment may not be routinely visualised by some surgeons who undertake knee arthroscopy. Increased age, female sex, raised BMI and varus alignment have all been associated with a higher incidence of medial root tears (38,39,40). Medial meniscus posterior root attachment tears are often more chronic and degenerate in nature, and may not be associated with an acute event.

Lateral Meniscus Posterior Root Tears
It has been suggested that the increased mobility of the lateral meniscus, results in the lateral meniscal root attachments being subjected to less stress than the medial side.(33,40,41). However the lateral meniscus is known to be an important restraint to the pivot shift (42) and injury to the lateral meniscus is implicated as a cause of the high grade pivot shift (43,44) Tears of the lateral posterior root have been observed in 7-9.8% of patients with an ACL rupture (45,46). The risk factors for tears here are largely unknown, associations with sporting activity and pivot-contact sports have been noted. (47,48) (Figure 5)

figure-5

Diagnosis
Clinical Presentation
Clinical diagnosis of meniscal root tears remains challenging. The signs and symptoms that commonly manifest with typical meniscal tears may not be present with meniscal root tears. Patients may present with joint line tenderness but without mechanical symptoms. Lee et al (49) found that in their series of 21 patients with medial meniscus posterior root attachment tears, only 14.3% and 9.5% of their patients, respectively, complained of locking and giving way. Most patients with a medial root tear do not recall a specific event leading to their pain (50). On examination, the most commonly encountered signs are posterior knee pain with deep flexion (66.7%) and joint line tenderness (31.9%). McMurray’s test may be positive in 57.1% and an effusion present in only 14.3% of patients (49). Seil et al (51) described a novel test for medial meniscal posterior root avulsions: the patient was fully relaxed and the knee in extension; during varus stress testing, the anteromedial joint line was palpated and meniscal extrusion was reproduced. Extrusion disappeared when the leg was brought into normal alignment. The reliability of this test, however, is currently unclear and we have not found it to be particularly useful.
figure-6-and-7-final

Diagnostic Imaging
In addition to the difficulties of clinical diagnosis, accurate radiological diagnosis is heavily reliant on imaging quality and the expertise of the reporting radiologist. In a study of 67 patients with arthroscopy proven posterior medial meniscal root tears, only 72.9% were detected by pre-operative MRI scanning, the remaining patients showed degeneration and /or fluid accumulation at the posterior horn without a visible tear(40). The posterior root of the medial meniscus may be best visualised on 2 consecutive T2 coronal MRI images as a band of fibrocartilage anchoring the posterior horn to the tibial plateau (Fig. 6). Meniscal root tears may be difficult to visualise directly and the relatively small size of the meniscal roots means that tears may be missed by standard 2 mm MRI sections. The presence of medial meniscal extrusion has been described as having a high correlation with the presence of a posterior root tear (Fig. 7) Meniscal extrusion is defined as partial or total displacement of the meniscus from the tibial articular cartilage. (52,53) More than 3mm of meniscal extrusion, on mid-coronal imaging, has been shown to lead to articular cartilage degeneration and is associated with complex meniscal tear patterns and tears of the posterior roots (53,54). Not all cases of meniscal extrusion, however, are a result of root tears. Magee (55) hypothesised that there may be a group of patients who stretch their meniscal roots, leading to extrusion but without a frank tear. Meniscal extrusion is less common in lateral tears for a number of reasons.

figure-8-and-9

The lateral compartment is subject to lower contact pressures than the medial side and hence lateral extrusion is less likely to occur. In addition to this, the lateral posterior root has further anchorage from meniscofemoral ligaments. They provide additional restraint to extrusion with a reported rate of 14% lateral meniscal extrusion if they are intact (56). If the meniscofemoral ligaments are not present or torn, in the setting of a posterior root tear, the extrusion rate of the lateral meniscus quadruples and approaches that of the medial meniscus. Another surrogate sign of a root tear is a ‘ghost sign.’ (Fig. 8) On a sagittal MRI cut, both the anterior and posterior horns should be visible. If the anterior horn is present but the posterior one is not, it is termed a ‘ghost meniscus.’ This finding is highly suggestive of a root tear and will often be found in tandem with extrusion on the coronal cuts (54,57). We have also found that the axial T2 weighted sequence to be useful for identifying meniscal root tears, particularly radial tears adjacent to the meniscal root. (Fig. 9). Tibial bone marrow oedema may be noted adjacent to the root attachment in acute meniscal root avulsion (Fig. 10). Bone marrow oedema, seen more peripherally in tibia, or affecting the medial femoral condyle may develop as the result of overload within the compartment, as a result of loss of meniscal function following a medial root tear (Fig. 11)

figure-10

Arthroscopic Assessment of the meniscal root attachments.
Due to the difficulties of accurate clinical and radiological diagnosis, the gold standard for determining the presence of a meniscus root tear remains arthroscopic assessment (55).

figure-11

Placement of the anterolateral arthroscopy portal high and adjacent to the patella tendon facilitates viewing of the medial meniscus posterior horn root attachment with the arthroscope placed in the intercondylar notch, adjacent to the PCL (Fig. 12). Sometimes soft tissue (synovium and fat) overlying the PCL may need to be removed with either shaver or radio-frequency ablation device to improve the view of the posterior root attachment of the medial meniscus (Figure 13). The senior author has not found a “reverse notch plasty” (as described by some authors (58)) to be necessary, however, a medial collateral pie crusting is almost always required for medial posterior horn root repair.

figure-12

Classification
The most commonly used classification system for posterior root tears is the LaPrade classification (Figure 14) (59). This is an anatomic classification system: Type 1 (7% of tears) are partial thickness, stable root tears. Type 2 (68% of tears) are complete tears within 9mm of the root attachment; this is further subdivided into 2A, 2B & 2C, located 0-3, 3-6 & 6-9mm respectively from the root attachment.

figure-13-and-14

Type 3 (6% tears) are a bucket handle tear with complete root detachment. Type 4 (8% tears) are complex oblique tears with complete root detachments extending into the root attachment. Type 5 (8%) are bony avulsion of the root. This classification is purely anatomical and does not offer a guide to treatment or prognosis. West et al. classified lateral meniscus root tears associated with an acute ACL injury. Three types of tear were identified at arthroscopic assessment: Type 1 were root avulsions. Type II were isolated radial split tears within one centimetre from the root insertion. Type 3 were complete root tears with radial and longitudinal elements (60). Another classification has also been described relating to the integrity of the menisco-femoral ligaments (MFL): Type 1 tears are avulsions of the root. Type 2 are radial tears of the lateral meniscus posterior horn with an intact meniscofemoral ligament. Type 3 is complete detachment of the posterior meniscus horn (61). Again these classifications are descriptive and do not, yet, guide treatment or prognosis, although it is suggested that lateral meniscus posterior root tears, in which the meniscofemoral ligament remain intact, may not require treatment.

figure-15

Treatment
There are three treatment categories for meniscal root tears: non-operative, partial meniscectomy and meniscal repair. Historically, the first two options have dominated. Non-operative treatment of these injuries still has a role. In poor surgical candidates (multiple co-morbidities, advanced age or significant underlying degenerative joint disease) an initial trial of non-operative treatment remains an appropriate first line treatment. When considering surgery, particularly when repairing these tears, it is important to appreciate any coronal plane malalignment that may be present in the patient. For example: repairing, and not offloading, a posterior medial root tear in a patient with significant genu varum, may be at higher risk of failure unless a concomitant corrective osteotomy was undertaken to offload the compartment and the repair (Fig. 15)

Non-Operative Treatment
Non-operative treatment fails to address the abnormal biomechanical environment that these tears create, and may lead to progressive osteoarthritis (62). In certain groups of patients (elderly, the obese, poor surgical candidates, or patients with advanced underlying degenerative joint disease) non-operative treatment may be reasonable. Symptomatic treatment with NSAIDs (oral or topical), activity modification and offloading braces may alleviate the joint pain associated with root tears. Initial bone marrow oedema as a result of the changed loading in the compartment may settle.

Operative Treatment
Meniscectomy
Historically, partial or total meniscectomies have been performed for root tears, typically providing short-term symptomatic relief with unknown long term consequences. An recent retrospective study of 58 patients with medial meniscal root tears who underwent either meniscectomy or root repair reported that while both treatments significantly improved subjective outcome scores (Lysholm & IKDC scores, p < 0.05), the repair group had more improvement and less progression of arthritis at mean follow up at 4 years (30). For patients with chronic root tears and symptomatic grade 3 or 4 chondral lesions who fail non-operative treatment partial meniscectomy remains the treatment of choice. If resecting a root tear, care must be employed not to debride the whole footprint otherwise a functionally meniscectomised knee will be created. Advantages of partial meniscectomy over repair are decreased operative time, less taxing post op recovery regime and an earlier return to sports / activities.

Meniscal Root Repair
Meniscal root tear repair may provide symptomatic relief and reduce abnormal articular cartilage loads implicated in the development of degenerative joint disease. Indications for meniscal repair are expanding but at present the main indications for root repair are: (1) acute traumatic root tears in patients with no underlying arthritis, with the aim of preventing the development of arthritis & (2) chronic, symptomatic root tears in young/middle aged patients without significant pre-existing arthritis (23,63). Lateral meniscus tears are most commonly associated with ACL tears and should be repaired concomitantly. Medially there are usually two distinct injury patterns – acute & chronic. An acute tear is often associated with the multi-ligamentous injured knee, particularly a complete MCL tear where the meniscocapsular ligaments are intact but the meniscus is avulsed from the root (63). In this setting there is a clear indication for meniscal root repair to prevent progressive joint failure. Conversely, chronic injuries are much more insidious in nature and have been reported to result in rapid ipsilateral compartment cartilage degeneration if undetected (63). The treating surgeon must distinguish if the tear is causative or resultant from the arthritis, which can be a difficult distinction to make. If there are only early chondral changes on imaging with evidence of a root tear and meniscal extrusion, repair would be indicated to prevent progression of arthritis. The two most common methods of meniscal root repair are: transosseous suture repairs and suture anchor repairs. It is important to note that non-anatomical meniscal root repair has a substantial deleterious effect on meniscal function (64).

Suture Anchor Technique
This technique has a theoretical advantage that it does not involve drilling a tibial tunnel, which may be useful in the presence of concomitant ligamental reconstruction. It uses “all-inside” fixation, and avoids the need for a distal fixation which potentially places abrasive forces on the sutures used. The shorter menisco-suture construct may reduce micro-motion at the repair site (65) The technique does, however, require the placement of a posterior arthroscopic portal. The technique described by Engelsohn et al (66) used an accessory posteromedial portal. The repairs were tensioned using standard arthroscopic knot tying techniques from the anteromedial portal. The authors stated that in a ligamentously stable knee, the accessory (high PM) portal was necessary to achieve appropriate anchor placement. Others have reported a similar technique for repair of posterior medial root tears, with placement of high PM portal, approximately 4cm above the joint line and posterior to the medial femoral condyle, with insertion of a double-loaded metal suture anchor and suture passage using a suture hook and a shuttle suture(67).

Transosseous Tunnel Suture Repair
There have been several variants of this technique described (10,68,69,70,71). The advantage of transosseous repair is that a posteromedial arthroscopy portal is frequently not required. As with all cortical suspensory fixation methods, there has been concern about a ‘bungee effect,’ with transosseous tunnel meniscal root repair, and resultant micro-motion at the repair site as a result of the long menisco-suture construct. Feucht et al (65) found that transosseous root repair resulted in 2.2mm +/- 0.5 mm of displacement under cyclical loading in a porcine model compared with 1.3 mm +/- 0.3 mm with suture anchor repair. However, although associated with less micro-motion the technique of placing a suture anchor in a small space while achieving accurate reduction of the tear and preserving the native articular cartilage is technically challenging. Yung et al (67) reported that the suture anchor may loosen and protrude into the joint over time. LaPrade advocates the use of two tibial tunnels for repairs of radial tears of the medial meniscus, siting less gaping after cyclical loading in laboratory conditions, and also significantly stronger ultimate failure loads. (72) We have found that trans-osseous repair allows accurate tear reduction and may also enhance meniscal healing due to the effect of the trans-tibial drilling, with stem cells from the bone marrow entering the intra-articular space (65). It is the senior author’s (JRR) preferred technique of fixation: a standard arthroscopy is performed via anteromedial and anterolateral portals. An accessory anteromedial portal may also be used. In medial repairs, a ‘MCL pie-crusting’ is almost always required to gain sufficient access to the tear and posterior root attachment side (Figure 16 a and b) . This technique has been shown to increase the medial joint opening by 3-4 mm (73,74) and does not result in long term valgus laxity or adverse clinical outcomes (75).  The tear is identified and the root attachment repair site is debrided using an RF wand, /shaver / curette to remove scar tissue down to bone to improve healing. Using arthroscopic graspers, the meniscus is pulled towards the attachment site to ensure that the tear may be reduced (Figure 16 c) .Particularly in chronic cases is may be necessary to mobilise the torn meniscus by freeing it from a scar tissue adherence to the the posterior capsule. This may be achieved with arthroscopic scissors and / or RF wand. With the root attachment site prepared and the tear mobilised, a tip aimer is introduced through the antero-medial portal. We utilise an standard ACL tip aimer for lateral meniscus root repairs (Accufex, Smith and Nephew, Andover MA). For medial meniscus posterior horn repairs, however, we use the labral repair attachment for the Accufex aimer which is flat and more easily positioned at the posterior horn root attachment site without injuring articular cartilage (Figure 16d). Tip aimers specific for meniscus root repair are commercially available. A 2.7mm passing pin is drilled to the meniscus root attachment site and then over drilled with a 4.5mm cannulated drill. The drill is left in situ and loop of No1 nylon passing suture passed up the drill with a suture passer, grasped and retrieved through the anteromedial portal (Figure 16e).  An 8 mm arthroscopic cannula is placed into the AM portal facilitate suture management and passage. A suture passing device may then be used to pass suture or tape across the meniscus (Figure 16f). The senior author prefers the FirstPass ST device (Smith and Nephew, Andover, MA) as it may be used to pass 2 mm tape (UltraTape, Smith and Nephew, Andover, MA) directly across the meniscus (Figure 16 g). 2 tapes are normal used (Figure 16h) although sometime 3, particularly if there are vertical splits exist in the meniscus (more common with chronic tears and it is necessary to have tape on both sides of the vertical split). For medial meniscus posterior horn root repairs in tight knees, despite an MCL pie crust, access for the suture passing device may be difficult and risk articular cartilage injury. In this situation a 70 degree suture passer (eg AcuPass, Smith and Nephew, Andover, MA) may be used to pass a loop of nylon across the meniscus and this then is used to shuttle the tape across the meniscus. Once passed through the meniscus, the tapes are individually passed down the trans-osseous tunnel. Reduction of the tear is then performed under direct vision (Figure 16 i) by pulling on the tapes which are then tied over a post screw and washer of a button at the external aperture of the trans-osseous tibial tunnel creating a suspensory fixation. In vitro studies have suggested that the use of two parallel tunnels may reduce displacement of the repair (76). Different suture repair techniques have been trailed in the laboratory. Knopf et al. (77) showed that a simple number 2 suture repair using 2 sutures had the lowest pull out strength (Mean approx 60N load to failure). More complex suture patterns (loop suture and modified Kessler) improved pull out strength, however more complex suture patterns are prone to creep and subsequent displacement of the repair. The use of tape improves the pressure distribution on the meniscus and pull out strength (Robinson et al. unpublished data).

figure-16

Postoperative Rehabilitation
It is important to note that no fixation method is able to restore the strength of the native root attachments. Improved healing rates have been shown in studies where patients were kept non-weight bearing for more than 8 weeks (10,30,48). A slow, conservative post-operative rehabilitation is therefore recommended (77). Most authors advocate full leg extension in either a cast or knee brace (30,32,48,68) for 2 weeks after repair. We allow flexion after this, however this is limited in order minimise stress on the repair to 0-90 degrees for medial meniscal root repairs and 0-70 degrees for lateral (because of the increased antero-posterior excursion in the lateral compartment with knee flexion (78). No loaded flexion greater than 90 degrees or twisting is allowed for 3 months post-op. Return to full activities or sports is generally achieved at 5-6 months post-operatively.

Clinical Outcomes
Studies reporting the outcomes following meniscal root repair are generally limited to case-series or cohort studies. It is perhaps unsurprising that the results are somewhat conflicting (48,65,67,79,80,81) given that the indications for meniscal root repair techniques have evolved and that several different surgical techniques are described.  All clinical studies report improvement in subjective outcomes measures at 2-3 years after repair (48,49,67,79,80). Structural outcomes evaluated with MRI or second look arthroscopy have produced conflicting results. Kim et al (50) reported reduced (improved) extrusion following both trans osseous tunnel and suture anchor type repair techniques, but Jung et al (79) found no change in meniscal extrusion after suture anchor repair. Moon et al (80) reported increased meniscal extrusion following the trans-osseous suture technique however, the patient population included people with severe osteoarthritis and a relatively high age (59 years), the poor results may have been attributable to these patient factors, both of which are are considered by some to be contra-indications to meniscal root repair. However other authors (R LaPrade, personal communication 2016) have not shown worse results related to patient age, given the absence of significant arthritic change.  Lee et al (49) performed second look arthroscopies in 10 patients who had under gone trans-osseous repair, they found healing in all patients 2 years after repair. Conversely, Seo et al (79) performed second look arthroscopies in 11 patients and found that none had complete healing at 1 year post-operatively. However, 82% of these patients, had chronic meniscal root tears, perceived as having a poorer healing capabilities (76,79). Importantly, the timing of the introduction of weight bearing postoperatively appears to have an important role in the success of healing of the meniscus root repair. Studies in which where weight bearing was allowed prior 6 weeks showed poorer healing rated compared with those in which the introduction of weight-bearing was delayed until to 8 weeks post-operatively (49,50,67).

Conclusions
Meniscus root repair is technically demanding with a steep learning curve. However, techniques are becoming more reproducible and straightforward, particularly as instrumentation to facilitate the procedure has improved and continues to evolve. The basis of treatment is founded upon sound biomechanics principles that have been robustly demonstrated in laboratory studies and the clinical finding that root injuries can lead to rapid joint failure. Meniscus root repair demonstrably improves the meniscal function of load transmission, rendering biomechanics close to the intact state. The objective is to slow or prevent joint deterioration yet, established osteoarthritis would appear to a be a contra-indication to repair. Whilst there are studies showing improvements in patient outcomes following meniscal root repair the impact on delaying the progression of osteoarthritic change remains to be unequivocally demonstrated and it would be wise for enthusiasm in this regard to be moderated until further studies have reported longer-term outcomes.


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How to Cite this article:. Robinson JR and Jermin PJ. Meniscal Root Tears: Current Concepts. Asian Journal of Arthroscopy  Aug – Nov 2016;1(2):35-46.

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Outside -in Meniscus repair

Sachin Tapasvi, Anshu Shekhar

Volume 1 | Issue 2 | Aug – Nov 2016 | Page 19-22


Author: Sachin Tapasvi[1], Anshu Shekhar[1]

[1] The Orthopaedic Speciality Clinic, 16 Status Chambers, 1221/A Wrangler Paranjpe Road, Pune 411004.

Address of Correspondence

Dr Sachin Ramchandra Tapasvi
The Orthopaedic Speciality Clinic, 16 Status Chambers, 1221/A Wrangler Paranjpe Road, Pune 411004
Email: stapasvi@gmail.com


Abstract

Meniscus tears are common knee injuries presenting to an arthroscopy surgeon. Repairing the meniscus to salvage knee function and biomechanics is indicated where ever possible, since the problems after meniscectomy are well established now. Inside-out meniscus repair is a very useful technique to repair tears in the posterior and middle third of both menisci. Proper adherence to technique and safety incisions reduce the risks and complications to almost the level of an all-inside meniscus repair. The technique allows precise placement of sutures, causes minimal meniscus tissue trauma, has produced good healing rates, is cost-effective and is basically, an indispensable tool in the armamentarium of any knee surgeon.
Key Words: Meniscus, Meniscus repair, Inside-out, Safety incision, Complications.


Introduction

Meniscus injuries are one of the most common findings in an orthopaedic practice. These injuries lead to a devastating effect on knee dynamics ultimately leading to arthritis. Studies by Fairbanks [1] suggest that the contact stresses after meniscectomy increase considerably leading to symptoms and knee dysfunction. The main function of meniscus, which is to increase surface area for contact of femur over tibia and also to act as a shock absorber for impact activities makes it mandatory to try and save the meniscus whenever possible. Since then the main focus of arthroscopists is to repair and preserve the meniscus. Ikeuchi described the first technique of meniscus repair in Tokyo in 1979 [2]. Over the years, many surgeons have developed techniques for meniscus repairs. The focus of this article is to have an overview of outside-in repair technique for meniscus repair. The outside-in meniscus repair is basically a technique where suture material is passed from outside the knee, retrieved inside the joint and then looped around the tear, again tunneled outside the joint where free ends are tied over the joint capsule. This technique requires the least expensive material and also gives the surgeon modularity to modify the technique to his liking. Many modifications have been done to reduce the cost and simplify the procedure which we will be looking at in details.

Indications
Meniscus repair probability depends on site, size and type of tear. The ideal indication of outside-in meniscus repair is vertical or longitudinal tear in peripheral third of meniscus in a young patient with a stable knee or if the patient is going to have a concomitant ligament reconstruction. For outside-in technique, because we insert a sharp instrument blindly into the joint, the indications are
1: Anterior horn tears
2: Vertical and Longitudinal tears in anterior 2/3rd of meniscus.
* Posterior horn tears may also be tackled by outside-in technique but it has a risk of neuro-vascular injury.

figure-1

Techniques
Many techniques for outside-in meniscus repair are proposed, each one following the same principle but tweaked by authors to make it either efficient or simpler. General preparation for meniscus repair includes high tourniquet, a leg stopper to keep the leg in 90 degree flexed position [3]. After painting and draping the leg, arthroscopy is performed to identify the site and type of the tear. Medial meniscus tear should be tackled in 10o degree flexion with valgus stress to tighten the capsule. Transillumination can be used to identify the saphenous vein and nerve before a needle is inserted, thus avoiding damage to those structures. Anterior horn tears are repaired in 60o to 90o of knee flexion and the needle insertion site is kept anterior to the pes anserinus to avoid saphenous nerve and vessels. Lateral meniscus tears are repaired in figure-of-4 position so that the peroneal nerve shifts posterior to the joint-line. Posterior horn tears of medial meniscus are best repaired when the needle is placed just posterior to pes anserinus tendons in 10-15o flexion, for lateral meniscus posterior horn tears the knee is kept in figure of 4 or 90o flexion. Abrading the torn surfaces of meniscal fragments with a meniscal rasp helps increase the healing potential. A needle is placed in the torn fragments, one in the femoral side and other in the tibial side in horizontal tears, piercing both fragments in a longitudinal tear and one in anterior and other in posterior part of a radial tear. The orientation of suture can be vertical mattress or horizontal mattress sutures depending upon the type of the tear and accessibility. Vertical mattress sutures have more pull-out strength as they are able to co-apt the circumferential fibres of the meniscus. Reduction and suturing of fragments have various techniques which have been described by many authors. One of the earliest of the techniques described was the Mulberry knot technique, where two separate non absorbable suture thread are passed in the superior and inferior portion of the torn meniscus using a bold needle. The sutures are pulled out from the anterior viewing portal, a mulberry knot is tied to each suture thread and then the sutures are pulled out along with the needles through which they were inserted thus reducing the meniscus tear. The free suture ends are then tied over the capsule from the point where they were inserted. Other technique is when a knot is tied with a few throws of simple suture to the 2 sutures outside the joint and then 1 end is pulled back in the joint with the knot piercing the meniscus and finally forming a loop suture around meniscus. A dilator knot which is a small sized knot may be tied preceding the big knot to help it pass through the meniscus and not tear it when it is pulled. The suture ends are tied over the capsule. A monofilament steel loop which is commercially available may be used to retrieve sutures as well. In this technique a loop is passed through the needles in the joint and the sutures are sewn into the loop hole from the portals using a grasper. The sutures are then retrieved over the capsule by retracting the loop. The procedure is repeated with other end of the same suture and the loop coming in through other fragment of the meniscus and the 2 free ends are tied on the capsule. A non-absorbable suture loop may be used instead of readymade loops. The progression of sutures is advised to be consistent in a way that superior and inferior fragments in a cleavage tear are reduced in sequence of superior first then inferior with repetition of the same sequence to have a uniform reduction of meniscus. Bucket handle tears are first stabilised by a central reduction sutures, followed by an anterior and a posterior sutures in sequence for uniform reduction. Many modified outside-in techniques have been described by various authors. Keyhani et al [4] have described a technique for vertical and horizontal loop sutures for anterior and middle third meniscus tears. A No. 0 PDS suture is passed through meniscus tibial end with a bold needle and the intra-articular end is retrieved through the joint. The procedure is repeated with other free end of the suture passed through femoral surface of meniscus and retrieved through same portal as the first suture end. A sliding knot is tied with few simple knots over the meniscus and the free ends are cut. Ahn et al [5] described a technique for reducing and repairing a free unstable end of anterior horn of the meniscus after decompression of cyst. They used a Linvatec hook, used for all inside suturing, to pierce the anterior free end of the horn using the loop from anterior portal. A suture is passed within the hook and the end is retrieved from the portal. With both the free ends now out from the same portal a loop is passed with a needle from capsule piercing the meniscus from outside -In. Loop is retrieved through same portal as sutures. The sutures are retrieved over the capsule by passing them from the loop and then retracting the loop and the needle. The suture ends are then tied over the capsule using a small stab incision.Yiannakopoulis et al [6] showed a simple technique where they used a spinal needle / suture hook to pierce longitudinal tears at first posteriorly, retiring the suture through portal. Keeping the same suture in the needle, the meniscus is pierced again a bit anterior-ly and the free end again retrieved through portal anteriorly. The free ends are tied with sliding knot over the meniscus giving a simple and effective configuration. Landsiedl [7] used needles to introduce two suture loops, one anterior and other a bit posterior to the first one. Both loops are retrieved outside the joint through portal and tied together and then one end is pulled gain bringing the knot inside the joint, the knot passing through the meniscus and thus forming a loop suture over the meniscus. The free ends are tied over the capsule. Chong et al [8] wrote about a technique where they passed a Loop through needle piercing both fragments of the meniscus and through the anterior portal introduced a reverse loop via needle with free ends inside the joint and loop end outside the joint . The free end is passed through the loop and loop is pulled with the suture. The process is repeated with the other free end of the reverse too and then when the 2 ends are re-trieved outside the joint they are tied over the capsule leaving no knot in the joint.

figure-2

Complications
The technique of outside-in meniscus repair can be challenging and demanding. It may not always be possible to get the needles in right part of the meniscus or perpendicular to the tear in the first place. These techniques require a longer learning curve and patience to get sutures and needles placed in right spot. The outside-in technique has two stages which are critical. One is when a sharp pointed instrument is inserted in the joint and other while securing the suture by tying a knot over the capsule. Though techniques and landmarks are defined by many authors to avoid these injuries clinical practice not being perfect leads to these complications. Peroneal nerve injury is common if the knee is not placed in enough flexion and needle is inserted posterior while doing lateral meniscus repair. Saphenous nerve is at risk of injury during medial meniscus repairs. Posterior neurovascular structures are at risk of injury while performing Posterior horn medial meniscus (PHMM) repair. Hassad Sobhy [9] and colleagues carried out cadaveric dissections to evaluate the safety of outside-in meniscus techniques while performing PHMM repairs. They concluded that inserting a needle through a slit in the skin just over the semitendinosus has significant lower risk of damaging either popliteal vessels or saphenous nerve. Chondral damage during insertion of needles into the joint is a well-known complication. This can be avoided by carefully placing the needles and not thrusting them in. Intra-articular knots which are used to secure the repair in some techniques are also a cause of problems. Kelly IV and colleagues [10] carried out a second look arthroscopy in patients who had synovitis after meniscal repair with mulberry knot technique. They evaluated the prevalence of aseptic synovitis and evidence of chondral damage. The synovitis and clinical symptoms subsided after partial meniscectomy. Retears and healing problems are also part of the complications spectrum. Healing problems are most common in the posterior third of the meniscus since it is difficult to get the coaptation right due to improperly oriented needles. Posterior capsule tightness in a repair done in excessive flexion may also lead to extension loss.

Results
The results for outside in meniscus have been extremely promising. Out of the studies which have evaluated healing rates and outcome of meniscal repair, all of them have good healing rates with outside-in technique. This may be due to modularity that the surgeon has while placing the sutures. In a study by Morgan and Casscells [11] which evaluated clinically their patients who underwent outside-in repair for posterior horn tears, the authors reported 98% good to excellent clinical outcomes. The fallacy of this study was that it was only a clinical as-sessment. Morgan et al [12] did a study of 353 meniscus repairs done by outside-in technique. He performed second look arthroscopy on 74 of them at average 1 year post op and found out of the 84 % patients who had asymptomatic healing, 65 % had complete healing and 19% had incomplete healed meniscus. Interestingly all of the failures were in ACL deficient knees. They also concluded that it takes around 4 months to have visual evidence of healing.
Van Trommell et al [13] evaluated patients with outside-in repairs at a mean duration of 15 months by second look arthroscopy, arthrogram or MRI. They found 74% patients had complete or partial healing. All the Re-tears were in posterior and middle third of meniscus. Posterior third of meniscus is notorious for poor healing. They attributed improperly placed sutures for these failures. Mariani et al [14] gave accelerated rehabilitation to their patients of ACL reconstructions with outside-in meniscus repair and found 77% good to excellent results. All the new and modified techniques described above in techniques section also showed good to excellent clinical outcomes in their respective study at mid-term follow up. Hantes et al [15] published the only study available where they evaluated and compared outside-in, inside-out and all inside meniscus repair techniques. They clinically evaluated 57 patients who underwent meniscus repair. 17 out of 57 were in outside-in cohort and showed 100% clinical healing rate as compared to 95 % of Inside-out and 65% of All-inside cohort. Only one patient had saphenous palsy which resolved over 4 months, as compared to inside-out cohort which had four incidences of nerve palsy. The only downside attributed to outside-in cohort is longest surgical time as compared to other cohorts with and average surgical time of 38.5 minutes.

Conclusions
Outside-in meniscus repair have stood the test of time to be the most effective meniscus repair techniques. It provides surgeons the ability to modify the procedure to their liking and giving certain modularity helps in perfecting the suture placement techniques. This has resulted in better co-aptation of torn fragments leading to stable repairs and better healing rates. This is a demanding technique  but has equally good proven results to make the steep learning curve worthwhile. The other advantage is less likelihood of complications if the identified landmarks and prescribed guidelines from previous studies are followed.  The material and equipment required for the surgery is  inexpensive and thus provides  good cost-cutting in patient care without compromise in the results. New and modified Outside-in repair technique still have to be explored but the existing ones provide for repairing most of the tears giving equally good if not better outcomes than other techniques.


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7. Landsiedl F. Improved outside-in technique of arthroscopic meniscal suture. Arthroscopy. 1992;8(1):130-1.
8. Chong KC, Chan BK, Chang HC. A simple method of meniscus repair using the arthroscopic outside-in technique. Arthroscopy. 2006 Jul;22(7):794.e1-5.
9. Sobhy MH, AbouElsoud MM, Kamel EM, Desouki AM. Neurovascular safety and clinical outcome of outside-in repair of tears of the posterior horn of the medial meniscus. Arthroscopy. 2010 Dec;26(12):1648-54.
10. Kelly JD 4th, Ebrahimpour P. Chondral injury and synovitis after arthroscopic meniscal repair using an outside-in mulberry knot suture technique. Arthroscopy. 2004 May;20(5):e49-52.
11. Morgan CD, Casscells SW. Arthroscopic meniscus repair: a safe approach to the posteri-or horns. Arthroscopy 1986;2(1):3–12.
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How to Cite this article:. Tapasvi SR, Shekhar A. Outside -in Meniscus repair. Asian Journal of Arthroscopy. Aug – Nov 2016;1(2):19-22 .

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Imaging of Meniscus Repair and Healing : A Review of Current Trends/ Literature

Anupama S Patil, Aparna H Chandorkar

Volume 1 | Issue 2 | Aug – Nov 2016 | Page 23-27.


Author: Anupama S Patil[1], Aparna H Chandorkar[1]

[1] Star Imaging and Research Centre, Joshi Hospital Campus, Opposite Kamla Nehru Park, Erandwane, Pune, India. Pin Code- 411004.

Address of Correspondence

Dr Anupama S Patil
Star Imaging and Research Centre, Joshi Hospital Campus, Opposite Kamla Nehru Park, Erandwane, Pune, India. Pin Code- 411004.


Abstract

Considerable developments have occurred in meniscal surgery, with increasing usage of meniscal repair as the preferred modality of treatment for meniscal tears, in order to preserve the meniscal morphology and physiologic function and to delay osteoarthrosis . Second look arthroscopy is considered the gold standard in assessing meniscal healing. However, arthroscopy being an invasive procedure, there is a need for developing accurate modalities for imaging of the post –repair status of the meniscus as a viable alternative to arthroscopy. Magnetic resonance imaging (MRI) is a good non invasive imaging modality for evaluation of meniscal healing . However, persistence of signals within a repaired healed meniscus on conventional MRI makes accurate interpretation difficult. MR arthrography (MRA), which involves addition of intra-articular contrast, increases the sensitivity and specificity of differentiation between healed scar and possible non healed repair/retear. CT arthrography is another imaging technique  which has been used for detection of retear; however it is limited in the degree of information it provides as compared to MRI/MRA. This review aims to discuss the different imaging techniques available for the evaluation of post repair meniscus and its healing and the advantages and disadvantages of the same.


Introduction

The meniscus is important for preserving a multitude of normal functions of the knee joint such as shock absorption, force transmission, stability maintenance and joint lubrication [1]. These critical functions of an intact meniscus make it important to preserve as much meniscal tissue as possible in patients with meniscal injury. Thus, meniscal repair [rather than menisectomy] has become the optimal treatment for meniscal tears, especially for vertical or oblique linear tears located in the vascular zone [2, 3]. The main diagnostic tools for assessment of meniscal repair and meniscal healing are clinical assessment, MRI/MR arthrography, CT arthrography and second look arthroscopy [2, 4-6]. Second look arthroscopy remains the gold standard in evaluating the healing status. However, because of its invasive nature and cost, MRI/MR arthrography and CT arthrography are emerging as fairly good alternatives to arthroscopy [7, 8]. Clinical assessment includes criteria such as medial joint line tenderness, joint swelling, locking, pain on extreme flexion and a positive McMurrays test. It is the simplest method of assessment of the patient, but it is highly dependent on the experience of the surgeon [9]. MRI is a non invasive method of assessing the meniscus. Evaluation of a post operative meniscus is a challenge as the diagnostic criteria for MR evaluation of tear in a repaired meniscus are different from those in a virgin meniscus [7, 10]. The presence of post-operative signals sometimes confound the reading of the MRI. Addition of intra-articular contrast further aids differentiation of scar tissue versus tear [3, 7, 10, and 11].  This narrative review aims to discuss the different imaging methods for evaluation of meniscus repair and healing and the advantages and disadvantages of the same.

Assessment of meniscal healing:
As opposed to in a virgin meniscus, mere presence of a grade 3 signal is not enough to make the diagnosis of a tear. The initial fibrovascular granulation tissue and later mature fibrocartilagenous scar produces increased signal intensity [grade 3] on the intermediate weighted sequences in a healing/healed meniscus [12]. This can cause fallacious interpretation of non- healing of the repair [7, 11, 13, 14] [Fig 1A]. Long segment tears and bucket-handle tears especially may have increased rates of grade 3 signal. This is because of the long injury length, which could induce more fibrocartilaginous scars and result in more grade 3 signals during the healing procedure [15].  Also the repairs with FasT-Fix showed more grade 3 signals than the other 2 repair patterns on the PD images. This is because FasT-Fix is non- absorbable and thus induces more reaction [15]. The signal intensity does reduce over time as the meniscus undergoes healing and may in fact disappear altogether [7]. Thus, diagnosis of meniscal tear by using the usual criterion of linear increased signal intensity extending to the surface on conventional short echo time MR images may lead to a false-positive diagnosis in patients after meniscal repair. Use of the stricter criterion of fluid signal intensity within a linear defect in the meniscus on T2-weighted images has been shown to provide high specificity (88%–92%) but low sensitivity (41%–69%) for tears [13, 16, 17]. The use of this stricter criterion with conventional MR imaging will result in fewer false-positive diagnoses, however, many tears will be missed. Identification of displaced meniscal fragments allows detection of tears with high confidence; however, displaced fragments are only seen in the minority of tears. Further addition of intra-articular contrast increases the sensitivity and specificity of diagnosis of tear[4, 11, 13, 16, 18, 19]. Extension of intra-articular contrast into the grade 3 signal indicates presence of a tear. The various imaging modalities that can be used for evaluation of a post-repair meniscus are as follows:

Conventional MRI
3T [high field strength magnet] and a dedicated knee coil are preferred for imaging as they provide high spatial resolution of the images obtained. The routinely performed conventional MRI sequences are PD [proton density, intermediate] sagittal and coronal, T2 sagittal, PD and T2 axial, T1 sagittal and 3D VISTA. The 3D VISTA sequences are then reformatted into the axial plane to delineate the morphology in the long axis of the meniscus. Presence of mildly hyperintense linear grade 3 signals on PD images is normal for many years after surgery Fig 1A. It represents initial fibrovascular granulation tissue and later fibrocartilagenous mature scarring. This turns less hyperintense on T2 [Fig 1B]. On intravenous administration of contrast, there is enhancement of granulation tissue, which reduces in intensity and extent over the next 12-18 months. [Fig 1C, 2A, 2B, 2C, 3A, 3B, 3C]. MR arthrography has some advantages over conventional MRI. Distension of the joint makes it more likely for the contrast to enter into the tear and delineate it. Lower viscosity of gadolinium compared to synovial fluid makes it more likely to extend into the tear. T1 W images which are used in MR arthrography have a higher signal to noise ratio and this improves spatial resolution [3].

figure-1a-1b-1c-and-1d

Direct MR arthrography
After the conventional MRI sequences are obtained, contrast [50 cc of gadolinium diluted 1:250 to 1:100] is injected into the knee joint under fluoroscopic guidance and multiplanar T1 W images are obtained thereafter [4]. Intra-articular contrast insinuates into a tear and delineates it on the post contrast T1 W images. This helps to differentiate a tear from a grade 3 signal which is merely a scar tissue.

figure-2a-2b-2c-2d

Indirect MR arthrography
The process of healing of the meniscus can be non- invasively assessed by indirect MRA. [7, 20]. After the conventional MRI sequences are obtained, gadolinium contrast [0.1 mmoles/kg] is injected intravenously and the joint is exercised for 20-25 minutes. After this, T1 W images are obtained in multiple planes [4, 7]. The advantage of this procedure is that it is non –invasive and can be performed by a technician or nursing staff . Also patient compliance is better than for direct arthrography [11]. According to some studies there is no significant difference in diagnostic accuracy between direct and indirect MR arthrography. Indirect MR arthrography is a less-invasive procedure. The presence of a physician and fluoroscopic guidance is not required, making it probably a better imaging approach than direct MR arthrogram [4, 11].  Hantes et al observed that the signal to noise ratio [SNR] of the repaired tear reduces significantly and approximately 50% from 3 to 6 months, and from 6 to 12 months postoperatively, as demonstrated with indirect MR arthrography [7]. However, in comparison to normal meniscus, the SNR of a tear remains 5.5 times higher 12 months postoperatively. In contrast, the reduction of SNR of the repaired tear at conventional MRI was not significant even from 3 to 12 months [7].

figure-3a-3b-and-3c

Normal findings in a post-repair meniscus on MRI /MRA:
It is important to know what the normal findings seen on an MRI of a post operative /repaired meniscus are, so as not to misinterpret these findings as abnormal or pathological.  Grade 3 signals are noted on the intermediate [PD/T1W] sequences extending to the articular surfaces. These may persist for many years after surgery and are attributed to fibrovascular granulation tissue in the initial post operative period and fibrocartilagenous tissue in the later post operative period. [4, 13, 16, 21-24]. These signals reduce in intensity over time. [20, 25].  There is some degree of shrinkage /reduction in the width of the meniscus after meniscal repair. This is different in different segments of the meniscus.  Some degree of enhancement is seen within the repair on the immediate post contrast images [for almost 12-18 months post operatively due to the presence of granulation tissue]. The intensity of enhancement reduces over the next 12-18 months. [Fig 2A, 2B, 2C, 3A, 3B, 3C]. There will however not be any extension of contrast into the signal on the MR arthrogram images [7, 8]. Persistence of enhancement in a meniscus 18 months post operatively suggests non-healing of the repair[Fig 4A, 4B] Occasionally a degenerative signal may be seen in a post operative meniscus many years after surgery due to the onset of degenerative changes [26].

figure-4a-and-4b

Criteria to suggest recurrent/residual tear on MRI /MRA
Bright signal seen within the meniscus on the T2 W images is more specific for a recurrent /persistent tear, especially 12 months post operative [3, 13, 16, 17]. After the administration of intra-articular contrast [either directly into the joint or indirectly by the intravenous route, extension of contrast into the signal abnormality on the MR arthrogram adds to the sensitivity and specificity of the diagnosis  [Fig 5A, 5B, 5C]. Sometimes displaced meniscal fragment may be identified which is then a definite sign of a retear [16, 27, 28].  The presence of a parameniscal or intrameniscal cyst suggests the presence of a residual /recurrent tear.  Presence of abnormal signal intensity at a site distant from the site of original repair indicates the presence of a fresh tear [3].  The healing process can also be classified according to Henning’s criteria, depending on healing in the thickness of the meniscus. A meniscus is considered healed if it heals over the full thickness of the tear, incompletely healing if it was healed over at least 50 % of the thickness of the tear and a failure was defined as healing less than 50 % of the thickness at any point along the length of the tear [29].

figure-5a-5b-and-5c
NOTE:
Assessment of a post operative meniscus [especially a post-repair meniscus] on MRI is difficult. Comparison with previous MRI studies is essential to know the exact location, extent and morphology of the prior year for interpretation of the signals seen on the post-operative study [11]. Even with addition of intra-articular contrast, the contrast may not enter the tear if the mouth/opening of the tear is very narrow. This will cause a false negative diagnosis.
It is also important to remember that not all recurrent pain after meniscal repair surgery is related to the meniscus. Chondral/osseous abnormalities and pes anserine inflammation can also occur and be the cause of pain [4]. [Fig 6]

figure-6-final-done

CT Arthrography
CT arthrography is another modality which may sometimes be used especially when there is non- availability of MRI or in patients in whom MRI is contraindicated. A volume of 10 cc iodinated contrast mixed with1 cc of 0.1%solution of epinephrine is injected under fluoroscopic guidance into the joint space. The patient is then asked to exercise the knee for 20-25 minutes. Thereafter a spiral CT scan is performed and the images acquired are reconstructed in the sagittal and coronal planes [5, 30]. Henning’s criteria for healing on arthro-CT correspond to “thickness” healing criteria. [31]. A meniscus was considered healed if it was healed over the full thickness of the tear. A tear was classified as incomplete healing if healed over at least 50% of the thickness of the tear. A failure was defined as healing<50% of the thickness at any point over the length of the tear.
There are some limitations to the use of CT arthrography. It cannot concomitantly evaluate ACL grafts and osseous abnormalities are not well assessed. The hazard of ionizing radiation and the possibility of complications ensuing from intraarticular injection of iodinated contrast material are also major disadvantages.

Second look arthroscopy
Second look arthroscopy remains the gold standard for assessment of meniscal healing. The disadvantage of this is that it is an invasive procedure and hence patient compliance is less. [23, 32-34].

Conclusions
Meniscal repair is increasingly replacing menisectomy as the treatment of choice especially in young patients in order to avoid early onset of osteoarthrosis. Imaging options such as MRI, MR arthrography and CT arthrography are being used as alternatives to clinical assessment and second look arthroscopy for the evaluation of meniscal repair healing. Conventional MRI has the disadvantage of grade 3 signals persisting for years after surgery even in a healed meniscus. The additional of a T2 W sequence on conventional MR imaging and usage of intra-articular contrast [MR arthrograms, direct and indirect] have increased the specificity, sensitivity and accuracy of diagnosis of unhealed menisci and retears.  Second look arthroscopy does however remain the gold standard for the diagnosis of retears, as of date.


References

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5. Vande Berg BC, Lecouve FE, Poilvache P, Dubuc JE, Bedat B, Maldague B, et al. Dual-Detector Spiral CT Arthrography of the Knee: Accuracy for Detection of Meniscal Abnormalities and Unstable Meniscal Tears.Radiology 2000; 216:851–857.
6. Pujol N, Panarella L, Tarik Ait Si Selmi, Neyret P, Fithian D, Beaufils P. Meniscal Healing After Meniscal Repair :A CT Arthrography Assessment. The American Journal of Sports Medicine 2008; Vol.36, No.8 :1489-1495.
7. Hantes ME, Zachosa VC, Zibisa AH, Papanagiotoub P, Karahaliosa T, Malizosa KN, Karantanasb AH. Evaluation of meniscal repair with serial magnetic resonance imaging: a comparative study between conventional MRI and indirect MR arthrography. European Journal of Radiology 50 (2004) 231–237.
8. Vance K, Meredick R , Schweitzer ME, Lubowitz JH. Magnetic Resonance Imaging of the Postoperative Meniscus. Arthroscopy 2009; 25, (5): 455-570.
9. Jones HP, Lemos MJ, Wilk RM, Smiley PM, Gutierrez R, Schepsis AA. Two-year follow-up of meniscal repair using a bioabsorbable arrow. Arthroscopy 2002; 18(1):64-69.
10. Lim PS, Schweitzer ME, Bhatia M, et al. Repeat tear of postoperative meniscus: potential MR imaging signs. Radiology 1999; 210:183–8.
11. Vives MJ, Homesley D, Ciccotti MG, Schweitzer ME. Evaluation of recurring meniscal tears with gadolinium-enhanced magnetic resonance imaging. Am J Sports Med 2003;31:868–73.
12. Arnoczky SP, Cooper TG, Stadelmaier DM, Hannafin JA. Magnetic resonance signals in healing menisci: an experimental study in dogs. Arthroscopy 1994; 10:552–7.
13. Farley TE, Howell SM, Love KF, Wolfe RD, Neumann CH. Meniscal tears: MR and arthrographic findings after arthroscopic repair. Radiology 1991; 180:517–522.
14. Bronstein R, Kirk P, Hurley J. The usefulness of MRI in evaluating menisci after meniscus repair. Orthopedics.1992 Feb;15(2):149-52.
15. Miao Y, Yu JK, Ao YF, Zheng ZZ, Gong X, Leung KK. Diagnostic values of 3 methods for evaluating meniscal healing status after meniscal repair: comparison among second-look arthroscopy, clinical assessment, and magnetic resonance imaging. Am J Sports Med. 2011 ;39(4):735-42.
16. Applegate GR, Flannigan BD, Tolin BS, Fox JM and Pizzo WD. MR diagnosis of recurrent tears in the knee: value of intraarticular contrast material. American Journal of Roentgenology. 1993;161: 821-825.
17. Lim PS, Schweitzer ME, Bhatia M, Giuliano V, Kaneriya PP, Senyk RM, et al. Repeat Tear of Postoperative Meniscus: Potential MR Imaging Signs. Radiology 1999; 210:183–188
18. Vahlensieck M, Peterfy CG, Wischer T, et al. Indirect MR arthrography: optimization and clinical applications. Radiology 1996; 200:249– 54.
19. Drape JL, Thelen P, Gay-Depassier P, Silbermann O, Benacerraf R. Intraarticular diffusion of Gd-DOTA after intravenous injection in the knee: MR imaging evaluation. Radiology 1993; 188:227–34.
20. Toms AP, White LM, Marshall TJ, Donnell ST.Imaging the post-operative meniscus. Eur J Radiol.2005 May ; 54 (2) : 189-98.
21. Pujol N, Nicolas T, Boisrenoult P, Beaufils P. Magnetic Resonance Imaging is not suitable for interpretation of meniscal status ten years after arthroscopic repair. Int Orthop. 2013 Dec; 37(12): 2371–2376.
22. Arnoczky SP, Cooper TG, Stadelmaier DM, Hannafin JA. Magnetic resonance signals in healing menisci: an experimental study in dogs. Arthroscopy 1994;10:552–7.
23. Eggli S, Wegmüller H, Kosina J, Huckell C, Jakob RP. Long term results of arthroscopic meniscal repair. Am J Sports Med 1995; 23:715– 20.
24. Muellner T, Egkher A, Nikolic A, Funovics M, Metz V. Open meniscal repair: clinical and magnetic resonance imaging findings after 12 years. Am J Sports Med 1999; 27:16–20.
25. Mustonen AO, Tielinen L, Lindahl J, Hirvensalo E, Kiuru M, Koskinen SK. MRI of menisci repaired with bioabsorbable arrows. Skeletal Radiol. 2006; 35(7):515-521.
26. Steenbrugge F, Verstraete K , Verdonk R.Magnetic reasonance imaging of the surgically repaired meniscus A 13-year follow-up study of 13 knees. Acta Orthop Scand 2004; 75 (3): 323–327 .
27. Sciulli RL, Boutin RD, Brown RR, Nguyen KD, Muhle C, Lektrakul N , Resnick D et al .Evaluation of the postoperative meniscus of the knee: a study comparing conventional arthrography, conventional MR imaging, MR arthrography with iodinated contrast material, and MR arthrography with gadolinium-based contrast material. . Skeletal Radiol. 1999; 28(9):508-514.
28. Magee T, Shapiro M, Rodriguez J, Williams D. MR Arthrography of Postoperative Knee: For Which Patients Is It Useful? Radiology. 2003 Oct; 229(1):159-63.
29. Popescu D, Sastre S, Garcia AI, Tomas X, Reategui D, Caballero M. MR arthrography assessment after repair of chronic meniscal tears. Knee Surg Sports Traumatol Arthrosc. 2015 Jan;23(1):171-7
30. Mutschler C, Vande Berg BC, Lecouvet FE, Poilvache P, Dubuc JE, Maldague B, Malghem J. Postoperative Meniscus: Assessment at Dual–Detector Row Spiral CT Arthrography of the Knee. Radiology 2003; 228:635–641.
31. Pujol N , Panarella L, Selmi TA, Neyret P, Fithian D, Beaufils P. Meniscal healing after meniscal repair: a CT arthrography assessment. Am J Sports Med. 2008 ; 36(8):1489-95.
32. Henning CE. Arthroscopic repair of meniscus tears. Orthopedics 1983:6:1130-1132.
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How to Cite this article:. Patil AS, Chandorkar AH. Imaging of Meniscus Repair and Healing : A Review of Current Trends/ Literature. Asian Journal of Arthroscopy  Aug – Nov 2016;1(2):23-27.

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Meniscus Ramp Lesion

Bertrand Sonnery Cottet, Sanesh Tuteja, Nuno Camelo Barbosa, Mathieu Thaunat

Volume 1 | Issue 2 | Aug – Nov 2016 | Page 28-34.


Author: Bertrand Sonnery Cottet[1], Sanesh Tuteja[1], Nuno Camelo Barbosa[1], Mathieu Thaunat[1].

[1] Investigation performed at the Centre Orthopédique Santy, FIFA medical center of Excellence, Groupe Ramsay-Générale de Santé, Lyon, France

Address of Correspondence

Dr Bertrand Sonnery-Cottet
Centre Orthopédique Santy, 24 Avenue Paul Santy, Lyon, 69008, France
Email: sonnerycottet@aol.com.


Abstract

Ramp Lesions of the Medial Meniscus (MM) are associated with 9 to 17% of ACL Tears and are seldom recognized on preoperative magnetic resonance imaging (MRI) scans. They also often remain undiagnosed when viewing from the standard anterior compartment arthroscopic portals. Improved visualization is the key to achieving good meniscal repair results as it improves diagnosis of longitudinal tears in posterior horn MM, safeguards better debridement prior to repair and ensures good approximation of the torn ends under vision. A systematic posteromedial exploration allows discovery of and debridement of the hidden MM lesion and repair with a suture hook device is associated with low morbidity and must be undertaken whenever possible.
Keywords: Medial meniscus, Ramp lesion, Repair, Healing, Anterior cruciate ligament, Knee.


Introduction

Meniscal lesions of the posterior horn of medial meniscus (MM) are very often associated with an ACL rupture (16,32,49). Certain specific lesions of the Medial Meniscus (MM) such as meniscosynovial or meniscocapsular tears and meniscotibial ligament lesions are associated with 9 to 17% of ACL Tears (8,21) and are seldom recognized on preoperative magnetic resonance imaging (MRI) scans (8,38). They also often remain undiagnosed when viewing from the standard anterior compartment arthroscopic portals including a probing. They were named in the 1980s by Strobel et al (42) as ‘‘Ramp’’ lesions of the meniscus and have drawn a lot of attention over the past few years (3,8,21,38,42). The aim of this article will be to write a narrative review of this Ramp meniscal lesion.

History
Hamberg et al (15) first described “a peripheral vertical rupture in the posterior horn of the medial or lateral meniscus with an intact body” in 1983. They repaired these lesions through a postero-medial vertical arthrotomy; with the belief that the capillary blood supply from the capsule aids healing of the meniscus. They reported promising results (84% healing) in old and new lesions alike, thus providing some valuable insight into the philosophy of meniscal conservation. Morgan et al (25) in 1991 described the first arthroscopic vertical suture of the PHMM using Polydioxanone (PDS) sutures with an outside-to-inside technique. They reported a 16% failure rate occurring in patients with a concurrent ACL injury. They proposed that the rotation axis of the knee joint was altered in an ACL deficit knee thus placing excessive loads on the posterior horn of the medial meniscus. The kinematics of the posterior horn of the medial meniscus in the ACL deficient knee was therefore not conducive to meniscal healing after repair despite a peripheral blood supply. They also noted that, when combined with an ACL reconstruction, peripheral meniscal repair healing rates improved and approached those obtained in an ACL intact knee (25). Ahn et al (5) in 2004 described the first clinical series of an arthroscopic all-inside suture technique for tears in posterior horn of medial meniscus. Using a suture hook thorough 2-posteromedial portals, PHMM tears were repaired with concurrent reconstruction of the ACL. They concluded that the arthroscopic all-inside vertical suture using a hook resulted in a high healing rate even in large and complex vertical tears. Seil et al (38) in 2009 highlighted the indications for meniscal repairs based on the presence of associated ligamentous injuries and morphology of the lesion.
They advocated that Meniscal repairs be ‘‘ideally’’ carried out in:
1. Young patients (< 40 years)
2. No associated joint degeneration.
3. Vertical lesions in the peripheral third of the meniscus (3mm of the meniscosynovial junction) (4) and in conjunction with an ACL reconstruction.
4. Significantly displaced bucket-handle tear or an MMPH tear with vertical step off (5).

Epidemiology
The prevalence for a meniscal lesion with an ACl tear has been reported between 47% to 61% (13,14). In 2010, S. Bollen et al (8) reported menisco-capsular lesions in 9.3% of their prospective series of 183 ACL reconstructions whereas Liu et al (21) described a prevalence of 16.6% in a series of 868 consecutive ACL reconstructions. In our series (40) on ACL deficient knees, a meniscal tears was identified in 125 out of the 302 patients. Following a systematic algorithm for exploration of the knee joint (Figure. 1), we found that; 75 (60%) medial meniscal body lesions were diagnosed through a standard anterior portal exploration, 29 (23.2%) ramp lesions were diagnosed during exploration of the posteromedial compartment, and 21 (16.8%) were discovered by probing the tear through a posteromedial portal and after minimal debridement of a superficial soft tissue layer with a motorized shaver. All-in-all, 42% (21/50) of the lesions diagnosed via inspecting the posterior compartment appeared only after superficial soft tissue debridement and were classified as ‘‘hidden lesions.’’ An ACL injury with an age at presentation above 30 years, male sex and a delay between injury and surgery are considered risk factors for concomitant meniscal lesions (8).

Biomechanical Implication on ACL
The importance of the meniscus in stabilizing the knee joint in chronically ACL-deficient knees has been validated by multiple studies (9, 39). A Peripheral posterior horn tear is caused by the recurrent trauma sustained by the Medial Meniscus, which acts as a ‘‘bumper’’ in ACL-deficient knees (2). In addition, contraction of the semimembranosus at its insertion along the posteromedial capsule may stress the peripheral meniscus, resulting in meniscocapsular tearing (17). This could occur at the time of injury or during subsequent instability episodes in the subacute or chronic situation (43). A capsular injury might also occur during the so-called medial contrecoup injury (18) after subluxation of the lateral tibial plateau and during subsequent reduction of the tibia (41).  A longitudinal tear of the PHMM in ACL-deficient knees increases the anterior translation of the tibia and a repair of this lesion reduces Anteroposterior tibial translation significantly at most flexion angles (17) and most prominently at 30 degrees of flexion (12, 30).  Peltier et al (30) observed that the PHMM was stabilised by the meniscotibial ligament posteriorly, which in turn inserted onto the posterior aspect of the proximal tibia. The capsule of the knee joint inserts more distally on this posterior surface. The posterior capsule hence lacks insertion onto the posterior aspect of the PHMM. Detachment of the ligament therefore results in an abnormal mobility of the entire PHMM, producing rotational instability. The authors observed that the division of the menisco-tibial ligament resulted in a statistically significant increase in internal tibial rotation. Such lesions occur either in the mid-substance (repairable) or as a bony avulsion (irreparable). Stephen et al (41) reported that the anterior tibial translation and external rotation were both significantly increased compared with the ACL-deficient knee after posterior meniscocapsular sectioning and these parameters were not restored after ACL reconstruction alone but were restored with ACL reconstruction combined with posterior meniscocapsular repair.
Classification [46] (Figure. 2)
We have proposed a classification for ramp lesions which is as follows:
Type 1: Ramp lesions. Very peripherally located in the synovial sheath. Mobility at probing is very low. (B)
Type 2: Partial superior lesions. It is stable and can be diagnosed only by trans-notch approach. Mobility at probing is low. ©
Type 3: Partial inferior or hidden lesions. It is not visible with the trans-notch approach, but it may be suspected in case of mobility at probing, which is high. (D)
Type 4: Complete tear in the red-red zone. Mobility at probing is very high. (E)
Type 5: Double tear.

figure-1-and-2

Surgical Technique (46)
With the patient supine on the operating table, a tourniquet is placed high on the thigh, and the knee placed at 90º of flexion with a foot support to allow full range of knee motion.  Using standard arthroscopy portals, high lateral as viewing and medial portal for instrumentation, articular inspection is performed and we engage a probe in the posterior segment of the meniscus and force an anterior excursion of the meniscus. If the meniscus subluxates under the condyle, it is an indicator for instability and an indirect sign of a ramp lesion. Direct visualization of the posteromedial compartment is mandated to diagnose and repair these lesions. Even if the meniscus appears stable on probing, a systematic exploration of the posterior segment must be performed using the protocol in (Figure.1) Through a Guillquist maneuver, the arthroscope in the anterolateral portal is advanced in the triangle formed by the medial femoral condyle, the posterior cruciate ligament, and the tibial spines. With valgus force applied initially in flexion followed by knee extension, the arthroscope is pass through the space at the condyle border of the medial femoral condyle. Internal rotation applied to the tibia further enhances visualization; this causes subluxation of the posterior tibial plateau causing a posterior translation of the middle third segment. Almost two-thirds of peripheral lesions can be diagnosed with this maneuver. Tears of the posterior segment must be approached posteromedially. The posteromedial portal is placed superior to the hamstring tendons and posterior to the medial joint line, also trans illumination allows observation of the great saphenous vein, that is in close relation to the infra-patellar branch of the internal saphenous nerve, that must be avoided.  The needle is introduced from outside to inside, in the direction of the lesion. The portal is prepared with a number 11blade scalpel under arthroscopic control. The all-inside suture is accomplished with or without a working cannula, depending on the surgeons choice. Using a shaver the lesion is debrided and the intervening fibrous tissue is excised. Suturing is carried out using a 25º curved hook (Suture Lasso, Arthrex): a left curved hook is used for a right knee and vice versa. The curved hook is loaded with a no. 2 non-absorbable braided composite suture (Fiberwire, Arthrex) or a absorbable no.1 PDS introduced through the posteromedial portal. The curved hook must penetrate the peripheral wall of the MM, and then the inner wall of the MM. The free end of the suture in the posteromedial space is grasped and brought out through the posteromedial portal. A sliding knot (fishing knot type) is applied to the most posterior part of the meniscus with the help of a knot pusher and then cut. The sutures are repeated as required depending on the length of the tear (usually we place a knot every 5 mm of the tear). During suturing, care must be taken to not splinter the meniscus that can occur with multiple failed attempts to pass the curved hook. Additionally, entangling of the sutures must be avoided. In some patients, the tear may extend to the mid-portion of the meniscus requiring further repair through the standard anterior portal with meniscal suture anchor and/or an outside-in suture. The stability of the suture is then tested with the probe.

figure-3

Post-operative
Post operatively, active and passive range of motion is limited to 0-90º in the first six weeks. Full weight bearing is allowed by six weeks post-operatively. Jogging is permitted after 4 months, pivoting activity at 6 months, and unrestricted activities by 9 months.

Results
Ahn et al (4) in 140 patients showed complete healing in 118, incomplete healing in 17 and failure 5 repairs. The clinical success rate was 96.4% (135 of 140). Healing was associated with the type of tear and location. Incomplete healing and failures had complex tears or tears involving the red-white zone. Seventeen patients had incomplete healing at second-look arthroscopy but had no clinical sign of a meniscal tear. The mean Lysholm score and HSS scores improved post surgery (Table. 1) and 134 (95.7 %) patients had a normal (104 patients, 74.3%) or nearly normal (30 patients, 21.4%) the objective IKDC scores. In our prospective evaluation (46) of 132 patients undergoing a MM repair through a posteromedial portal in conjunction with ACL reconstruction, fifteen patients were found to be symptomatic according to Barret’s criteria on follow-up (6). The clinical failure rate was 9%, 4.9% in the subgroup “limited tear” and 15.7% in the subgroup “extended tear.” A limited tear was defined as one restricted to the posterior segment whereas those with a tear that extended to the mid-portion of the meniscus were classified as an extended tear. The extended tears required an additional repair through the standard anterior portal with meniscal suture anchor and/or an outside-in suture. The extended lesions had an increased risk of clinical failure. Out of the fifteen, 9 patients underwent revision surgery. Nine patients (6.8%) had failure of the meniscal repair; 3.7% (3/81) occurred in the subgroup of limited tears and 11.7% (6/51) in the subgroup extended tears. In the subgroup of extended tears, the cumulative survival rate did not decrease significantly and were not associated with a significant increased risk of revision of the MM. The average subjective IKDC improved at last follow-up and The Tegner activity scale at the last follow-up was slightly lower than before surgery (Table. 1).

table-1

Complications
The main complications may be related to the posteromedial portal placement. Damage to the infra-patellar branch of the saphenous nerve due to a posteromedial portal has been reported owing to the proximity of the nerve to the portal site causing hypoesthesia or paresthesia below the patella (27). Having said that, hypoesthesia resulting from harvesting the Semi-tendinous and Gracilis tendons in a concomitant ACL reconstruction may be responsible for 74% of the times (35). Transient hypoesthesia of the Sartorial branch of the saphenous nerve has also been reported probably due to an access portal situated too anteriorly (24). McGinnis et al (23) studied the neurovascular safety zone for the posteromedial access and recommended a portal through the posterior soft spot located formed by the medial head of the gastrocnemius, the tendon of the semimembranosus and the medial collateral ligament at the posterior aspect of the joint line for creation of the posteromedial portal. Hemarthrosis due to the long saphenous vein injury may occur in the postero medial approach (27). Among other complications, an iatrogenic medial meniscus tear may occur from repeated attempts at suturing the meniscus with a curved hook, rending suture impossible. Also, to our knowledge no popliteal artery, common peroneal and tibial nerve lesions has been reported, however they are at risk of damage during creation of the posterior portals. These complications may be avoided by placing the posterior portals with knee in 90 degrees of flexion. This moves the neurovascular structures posteriorly, away from the posteromedial portal site. Also, the Guillquist maneuver that provides trans-illumination may help visualize the course of the superficial veins and the accompanying nerves thus preventing inadvertent damage (35). Our series (46) also has a low complications rate with only two cases of hemarthrosis post operatively. Also, no patient developed a neuroma around the location of the posteromedial approach, although it was difficult to be accurately determining the incidence of saphenous nerve lesions due to the posteromedial approach as the hamstring tendon harvesting can cause hypoesthesia in the different territories of the saphenous nerve.

table-2

Discussion
The forces acting on the MM increase by as much as 200% after an ACL injury. Furthermore, forces acting on the ACL replacement graft increase by 33% to 50% after a medial meniscectomy (12,28). Deficiency of the medial meniscus has therefore been proposed as a secondary cause of ACL failure. It has thus been recommended that an ACL-deficient knee be reconstructed to protect the menisci (39,50). Conversely, identification and repair of a ramp lesion during an ACL reconstruction is imperative to reduce the risk of secondary graft failures, as these lesions may increase the anterior tibial translation (2,12, 30) and subsequently the strain on the graft.  The success rates for meniscal repairs have been reported to be from 70% to 90% in vascular regions (11,13,16,36). Anh et al (12) reported a clinical successful healing rate of 96.4% in PHMM repairs with concomitant ACL reconstruction. Tenuta and Arciero (45) reported higher healing rates in concomitant ACL reconstruction than for isolated repairs (90% vs 57%). Meniscal repair in conjunction with ACL reconstruction has been reported to create a favorable environment for meniscal healing because of fibrin clot formation associated with intra-articular bleeding generated during ACL reconstruction (44).  Multiple techniques for suturing the meniscus are available. The indications, advantages and disadvantages of each are mentioned in (Table.2). The all-inside suture repair technique using a hook is especially useful in a ramp lesion, as the use of newer devices makes the repair procedure blind and placing a suture in the vertical configuration is technically challenging. In addition Choi et al reported that the use of meniscal devices failed to provide sufficient strength of fixation. They recommended that during suturing, the posteromedial capsule should be elevated and approximated to the PHMM to ensure precise approximation of tear site (10). In spite of the development of the newer all-inside suture devices, the failure rate of the repair of PHMM tears continues to remains high, (19) which may be attributed to various factors that include inadequate visualization and debridement of the lesions of the PHMM; failure to confirm the reduction of the lesion with the all inside technique (48) and tissue failure due suture pullout through the meniscal tissue (45).
The mechanical strength of the vertical suture is greater than that of the horizontal suture (45). Having said that, most meniscal fixators cannot facilitate meniscal repair in a vertical mattress fashion (7,34) especially in the posteromedial corner of the medial meniscus, small or tight knee joints. Sutures spaced at every 3 to 5 mm have been recommended however; the optimal number is unknown (44). Pujol et al (33) using meniscal devices reported an overall healing rate of 73.1%. van Trommel et al (47) reported similar results (76%) with the outside-in technique. (Table. 3) Both studies observed a strong trend toward a relatively lower healing rate of the posterior horn (Zone A), as compared with the body (Zone B). (Table. 4) They also observed that, partial healing in all tears extending from the posterior to the middle third of the medial meniscus. We observed similar results in our study with a higher failure rate in the extended tear subgroup (6/51) (46). Pujol et al (33) attributed this to the difficulty in performing an adequate abrasion of the posterior segment using standard anterior arthroscopic portals whereas van Trommel et al (47) attributed that same to the relatively anterior placement of the needles with the outside-in technique, making a perpendicular repair extremely difficult. This resulted in a decrease in the coaptation force of the sutures. In addition, they observed that an oblique suture placement in the posterior zone with the outside-in technique made the sutures enter more anterior than they exit. Ahn et al (5) postulated that a torn posterior menisco-capsular structure moved inferiorly against the remaining meniscus, displacing the tear during knee flexion. They suggested that this motion of the torn medial meniscus can partially explain the slow healing observed in MMPH peripheral rim tears despite a rich vascular supply to the red-red zone. Pujol et al (31) in 2011 reported a secondary meniscectomy rate of 12.5%. The authors observed that the volume of meniscus removed decreased in 35% of cases, with respect to the initial tear and noted that a secondary meniscectomy following repair can partially save the meniscus and the failure called a ‘‘partial’’ failure. They recommended that suturing a tear therefore preserved the meniscal volume in a subsequent meniscectomy performed for a failure of repair or repeat tears. Tachibana et al (44) reported newly formed meniscal tears occurring in an area different from the initial repair site, on the surface of 34.5% of the healed and incompletely healed menisci. These new injuries were 1 to 3 mm in length partial- or full-thickness lesions and located central to the peripheral repair. In our series (46), the high rate of recurrent tear was as a result of newly formed tears that were confirmed on the surface of 5 menisci. It is conceivable that these injuries were attributable to a residual cleft left by the path of the Suture Lasso and maintained by the use of a strong no. 2 non-absorbable suture.

table-3

These clefts on the avascular meniscal substance may remain in situ without healing and would favor the recurrence of a more centrally located lesion in the white-white zone. Using a small suture hook device may therefore be desirable as it may reduce the size of the clefts created during suturing. In addition, the ‘cheese wiring effect’ due to the higher co-efficient of friction of a non-absorbable suture may contribute to a failure. We therefore decided to change our suture from a strong non-absorbable suture to a number 0 or 1 PDS suture, which are recommended to reduce the risk of these newly formed injury (37).
Nepple et al (26) observed that the time between injury and repair was the most important factor influencing healing. The zone of tear in reference to blood supply is another major factor affecting the results of a meniscal repair and ramp lesions in the red-red zone are expected to heal more readily than are those in the red-white zone (20). The criteria for healing based on follow-up arthro-CT corresponding to thickness of healing was suggested by Henning et al (36) can supplement clinical evaluation to improve diagnostic accuracy (Figure 3). The clinical failure rate in a systematic review ranged from 0% to 43.5%, with a mean failure rate of 15% (22). Failures after two years represented nearly 30% (26). Although numerous studies have reported short-term outcomes of various techniques of meniscal repair, relatively few have reported medium to long-term outcomes. The rate of meniscal repair failure appears to increase from short-term follow-up to medium to long-term follow-up regardless of the technique (26). There are limited numbers of studies assessing the outcomes of meniscal repair using the PM approach (4,5,10,46). Further prospective analysis with long – term follow-up is required to validate the promising early results of meniscal repairs performed with this approach.  Finally, improved visualization is the key to achieving good meniscal repair results as it improves diagnosis of longitudinal tears in posterior horn MM (30), safeguards better debridement prior to repair and ensures good approximation of the torn ends under vision (1). It is thus important to perform a systematic exploration of the knee during an ACL reconstruction (Figure 1). A transnotch visualization combined with palpation of the meniscus with a needle or probe through the postero-medial portal aids in diagnosis of ramp lesions, which may otherwise be missed. Hidden lesions furthermore may be either very peripheral, covered by a layer of synovial or scar tissue or may not be reachable with a probe. It is therefore essential to identify these lesions during an ACL reconstruction and repair them whenever they are found to be unstable (40).

table-4

Conclusions
A systematic posteromedial exploration allows discovery of and debridement of the hidden MM lesion and repair with a suture hook device is associated with low morbidity. Failure Rates following a ramp lesion repair are low and occurs during the first 20 months. Even if a failure occurs the subsequent meniscectomy is limited and the volume of meniscal tissue debrided is reduced. An arthroscopic repair of meniscal ramp lesions should therefore be undertaken whenever possible.


References

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33. Pujol N, Panarella L, Selmi TA, Neyret P, Fithian D, Beaufils P. Meniscal Healing After Meniscal Repair A CT Arthrography Assessment. The American journal of sports medicine. 2008 Aug 1;36(8):1489-95.
34. Rankin CC, Lintner DM, Noble PC, Paravic V, Greer E. A biomechanical analysis of meniscal repair techniques. Am J Sports Med. 2002;30:492-497.
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40. Sonnery-Cottet B, Conteduca J, Thaunat M, Gunepin FX, Seil R. Hidden Lesions of the Posterior Horn of the Medial Meniscus A Systematic Arthroscopic Exploration of the Concealed Portion of the Knee. The American journal of sports medicine. 2014 Feb 24:0363546514522394.
41. Stephen JM, Halewood C, Kittl C, Bollen SR, Williams A, Amis AA. Posteromedial Meniscocapsular Lesions Increase Tibiofemoral Joint Laxity With Anterior Cruciate Ligament Deficiency, and Their Repair Reduces Laxity. Am J Sports Med. 2016 Feb;44(2):400-8. doi: 10.1177/0363546515617454. Epub 2015 Dec 11.
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How to Cite this article:. Sonnery-Cottet B, Tuteja S, Barbosa NC, Thaunat M. Meniscus Ramp Lesion. Asian Journal of Arthroscopy  Aug – Nov 2016;1(2):28-34.

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Inside-Out Meniscus Repair – A Review

Sachin Ramchandra Tapasvi, Anshu Shekhar, Shantanu Sudhakar Patil

Volume 1 | Issue 2 | Aug – Nov 2016 | Page 14-18


Author: Sachin Ramchandra Tapasvi [1], Anshu Shekhar [1], Shantanu Sudhakar Patil [1]

[1] The Orthopaedic Specialty Clinic, 16 Status Chambers, 1221/A Wrangler Paranjpe Road, Pune 411004.

Address of Correspondence

Dr Sachin Ramchandra Tapasvi
The Orthopaedic Speciality Clinic, 16 Status Chambers, 1221/A Wrangler Paranjpe Road, Pune 411004
Email: stapasvi@gmail.com


Abstract

Meniscus tears are common knee injuries presenting to an arthroscopy surgeon. Repairing the meniscus to salvage knee function and biomechanics is indicated where ever possible, since the problems after meniscectomy are well established now. Inside-out meniscus repair is a very useful technique to repair tears in the posterior and middle third of both menisci. Proper adherence to technique and safety incisions reduce the risks and complications to almost the level of an all-inside meniscus repair. The technique allows precise placement of sutures, causes minimal meniscus tissue trauma, has produced good healing rates, is cost-effective and is basically, an indispensable tool in the armamentarium of any knee surgeon.
Key Words: Meniscus, Meniscus repair, Inside-out, Safety incision, Complications.


Introduction

Once considered expendable, the vital role of meniscus in knee biomechanics is firmly established now. They are known for contributing to knee stability and congruity, resisting capsular and synovial impingement, load distribution and contribution towards screw home mechanism[1]. With advances in arthroscopy in terms of technique, instrumentation, optics and biomaterials, meniscus salvage has become a thrust area in this field today. The three basic techniques of meniscus repair: outside-in, inside-out and all-inside each have their indications, advantages and pitfalls. Henning et al first described the inside-out technique of meniscus repair, involving meniscal and meniscosynovial abrasion to promote healing, cannulated suture-needle delivery system for suture placement, a posteromedial or lateral skin incision for suture needle retrieval[2]. Here, we review the inside-out technique of meniscus repair.

Indications For Inside-out Repair And Technique
A meniscus tear must first be deemed suitable for repair, before deciding on the technique to be used. A non-degenerated, longitudinal tear, less than 3 centimeter and in the peripheral vascular zone is most amenable to repair[3]. An inside-out meniscus repair can be performed for the mid-third and posterior-third longitudinal tear of both the menisci[4]. With advances in all-inside meniscus repair implants and technique, this has gradually become the standard method of repair for posterior third longitudinal meniscus tears, replacing the “gold standard” method of inside-out repair[5]. Middle third tears, however, are readily amenable to repair by the inside-out technique without significant risk to neurovascular structures and possibly, without the need for a safety incision. Radial tears repaired by an all-inside or an inside-out horizontal construct have similar maximum failure loads [6]. The most recent systematic review comparing all-inside with inside-out isolated meniscus repairs did not reveal any difference in the failure rates, functional outcomes, and complications between the two methods[7]. However, the inside-out techniques has some distinct advantages. The zone specific suture needle delivery cannulae facilitate more precise and controlled suture placement, while allowing for revision and improvisation[8]. Also, the finer needles cause less iatrogenic damage to meniscus tissue, compared with the heavier all-inside implant insertion needles. This is especially vital when the meniscus tissue is tenuous, or in case of a complex tear. The finer needles also provide greater number of fixation points and captures more collagen tissue[8]. Another important advantage of inside-out repair technique is the significant savings in terms of implant cost of expensive all-inside repair devices [8].

Surgical technique
Patient position for inside-out meniscus repair can be either with a leg holder and table broken or on a flat table with thigh side support. A proximal thigh tourniquet is used for good visualization. A diagnostic arthroscopy is first performed via an anterolateral portal. A high anterolateral portal is useful if a meniscus repair is planned, to allow the needles to pass over the tibial spines without struggle. The anteromedial portal is created under vision with the aid of a spinal needle to allow easy access to medial and lateral menisci[8]. Typically, for a lateral meniscus repair, the anteromedial portal is higher to allow needles to negotiate the tibial spine[9].

figure-1

A 70 degree scope placed through the notch is helpful in viewing far posterior tears[9]. Assessment of the tear is done to decide whether to proceed with a repair or to resect the meniscus. Preparation of the meniscus tear is done next to potentiate healing. Granulation tissue must be debrided from both sides of the meniscus tear. Abrading the meniscal and peri-meniscal synovium, both superiorly and inferiorly, with a meniscus rasp (Acufex, Andover, MA) is an useful augment and aids in healing response[10]. Trephination is believed to create vascular channels and increase blood flow from a more vascular to a less vascular area[11][12]. A useful trick in bucket handle tears is to prepare the edges of the tear while the meniscus is still displaced and access to both sides is easy[8] (Figure 1). Fibrin clot prepared from the patient’s own blood is also widely used to enhance healing. It not only provides a scaffold, but also acts as an initiator and activator of the healing process[13]. When a meniscus repair is being performed in isolation, performing a limited notchplasty of the lateral femoral condyle with a shaver to create postoperative hemarthrosis and deliver marrow elements is another method of biological augmentation[9].

  figure-2

A. Technique for Medial meniscus inside-out repair[9]:
A 3-4 centimeter vertical “safety incision” (Figure 2) in the posteromedial aspect of the joint, posterior to the medial collateral ligament is first made with the knee in 60-900 flexion, to relax the hamstrings and popliteal neurovascular bundle. Transillumination aids in precise placement of this incision, with two-thirds being distal to the joint line and one-third proximal to it. The saphenous vein is carefully protected and sartorius fascia is incised and split proximally and distally with Metzenbaum scissors to preserve the Sartorius, Gracilis, Semitendinosus and the Saphenous nerve, which lies posterior to the Sartorius. Deep dissection is carried out bluntly with Metzenbaum scissors to create a plane between the medial head of gastrocnemius and capsule. This dissection is better performed from distal to proximal. Dorsiflexion and plantar flexion of the foot aids is location of the proper plane. A Henning retractor or a small bent spoon is then inserted anterior to the gastrocnemius, which protects the popliteal neurovascular bundle, retracts the pes and gastrocnemius and deflects the needle medially for retrieval. Repair can then begin, starting posteriorly and working anteriorly, with the knee in 10-200 flexion. Visualization of posterior meniscus can be improved by pie-crusting of the medial collateral ligament just below the joint line, while applying a valgus-external rotation force. Zone specific single and double lumen cannulae (Acufex, Andover, MA) inserted from the anterolateral portal are used to keep the meniscus reduced and for precise placement of the needles. For tears very close to the posterior root, it might become necessary to insert a curved cannula from the anteromedial portal, the curvature being directed away from the midline, to achieve proper trajectory for the suture needle. Non-absorbable multi-strand, long chain ultra-high molecular weight polyethylene (UHMWPE) sutures on 10 inch long needles (No. 2-0 FiberWire, Arthrex, Naples, FL) are used for the repair. The cannula is retracted 3-5 mm when the needle is pierced to increase the accuracy. This is done for the femoral side first, attempting to achieve a vertical mattress configuration, as this provides greater capture of strong circumferential fibers of the meniscus[8] (Figure 3).

figure-3

This might create a puckering of the meniscus, which subsides when tibial sided sutures are passed in a similar fashion to create a stacked repair and provide better coaptation of the tear area[14] (Figure 4). The needles are passed by one assistant, while a second assistant retrieves them using a needle driver, clips it using a hemostat and cuts the needles, taking care to avoid needle stick injury to anybody. If the needle is not visible after passing 1-1.5 centimeter, it must be withdrawn and reinserted at the same or different location with a different trajectory. Multiple sutures maybe passed at 3-5 mm intervals. The sutures may be tied sequentially as they are passed or at the end, after all have been passed out. When tying the knots, the knee must be kept in near or full extension to avoid imbricating the capsule, effectively causing a capsulorrhaphy and consequent flexion contracture. Drains may or may not be used and closure of the safety incision is done in layers.

figure-4

B. Technique for Lateral meniscus inside-out repair[9]:
The general principles remain the same as for a medial meniscus repair, with some important differences. The lateral vertical safety incision is made in a similar fashion, posterior to the fibular collateral ligament, two-thirds distal and one-third proximal to the joint line. The interval between biceps femoris and iliotibial band is dissected bluntly with a pair of Metzenbaum scissors, the common peroneal nerve being posteromedial to the biceps tendon (Figure 5). Dissection between the lateral gastrocnemius head and posterolateral capsule is similarly begun distally and a finger is used to assess the proper plane by flexing and extending the ankle. Staying anterior to the biceps and gastrocnemius lateral head reliably protects the common peroneal nerve A Henning retractor or bent spoon is placed as for the medial side, between the capsule and gastrocnemius. The anteromedial portal is made higher to avoid the eminence of the tibial spine, under vision over a spinal needle with the knee in a figure-of-4 position. If need be, accessory high anteromedial portal can be made to improve suture needle trajectory. The cannula is never inserted from the anterolateral portal due to the potential risk to the popliteal vessels, which lie just posterior to the posterior horn of the meniscus. Though no problems have been reported, it is best to avoid the popliteus tendon and pass sutures adjacent to this structure[9]. Capsular capture is not a problem on the lateral side and hence, knot tying can be done with the knee in flexion.

figure-5

Discussion

Result
The inside-out repair technique offers a success rate of 60% to 80% for isolated meniscus repairs and between 85% and 90% when performed with a concomitant ACL reconstruction[5]. Horibe et al performed second look arthroscopy for 132 meniscus repairs by inside-out technique. They report 74% excellent (completely healed) and 17% good (incomplete healing, partial thickness defect, stable on probing) result in their cohort[14]. Choi et al compared the results of suture repair of meniscus tears with concomitant ACL reconstruction, by all-inside and inside-out techniques using polydioxanone sutures. They found no difference in the healing rates on magnetic resonance imaging and no difference in Lysholm scores or Tegner activity scales between the two groups[15]. A systematic review by Grant et al was done to compare the effectiveness and complications of isolated inside-out and all-inside meniscus repairs. There was no statistical difference in clinical failure rate- 17% for all-inside and 19% for inside-out techniques. Subjective outcome, as measured by Lysholm score and Tegner activity scale was also comparable between the two groups. Inside-out repairs however, require 50% greater operative time. Nerve related symptoms were commoner (9%) in the inside-out group than in the all-inside group(2%). Upon pooling of all complication data, the Odd’s ratio was 0.55 (95% confidence interval = 0.27, 1.10). 0.55 (95% confidence interval = 0.27, 1.10)[16]. In a more recent systematic review, Fillingham et al compared current all-inside repair devices with the classical inside-out repair for isolated meniscus tears. They reported no significant differences in clinical or anatomic failure rates (clinical failure: 11% for inside-out versus 10% for all-inside, respectively, p=.58; anatomic failure: 13% for inside-out versus 16% for all-inside repairs, p=.63). Mean ± SD Lysholm score and Tegner score for inside-out repair were 88.0 ± 3.5 and 5.3 ± 1.2, while the respective scores for all-inside repair were 90.4 ± 3.7 and 6.3 ± 1.3. Complications occurred at a rate of 5.1% for inside-out repairs compared to 4.6% for all-inside repairs[7].

Complications and Problems:
The various anatomic structures in the needle trajectory can potentially be injured. By deploying safe surgical practices, they can be avoided. These are some of the commonly encountered problems:
1. Saphenous nerve injury- It can be avoided by the medial safety incision and keeping the nerve, which lies posterior to the Sartorius, retracted behind the pes tendons.
2. Common peroneal nerve injury- The nerve lies posteromedial to the biceps femoris. Injury is avoided by keeping the knee in flexion while making the lateral skin incision and carefully developing the plane between the biceps femoris and iliotibial band.
3. Popliteal vessels- are most at risk while doing a posterior lateral meniscus repair. Careful placement of retractor and always passing suture needles from the anteromedial portal with careful retrieval, avoids injury to the vessels.
4. Flexion contracture may develop- when the medial side sutures are tied with the knee in flexion, thus over tightening the posteromedial capsule.
5. Needle stick injury to the surgeon or assistants- avoided by careful, unhurried movements[8].
The inside-out technique also has an increased operative time, compared to all-inside technique by about 50%[16].

Conclusions
The inside-out method of meniscus repair is an excellent technique to repair tears in the middle and posterior-third of both menisci. With the rapid development of all-inside meniscus repair devices, this technique may not remain the “gold standard” but still has an important role, especially in repairing large and complex tears. When care is taken to protect the neurovascular structures posteriorly, and with due diligence to correct surgical technique, it is a safe, cost effective and proven method to salvage the menisci whenever possible.


References

1. Renstrom P, Johnson RJ. Anatomy and biomechanics of the menisci. Clin Sports Med. 1990 Jul;9(3):523-38.
2. Henning CE. Arthroscopic repair of meniscus tears. Orthopedics 1983; 6: 1130–1132.
3. Taylor S.A., Rodeo S.A. Augmentation techniques for isolated meniscal tears. Curr Rev Musculoskelet Med. 2013 Jun; 6(2): 95–101.
4. Yoon KH, Park KH. Meniscal Repair. Knee Surg Relat Res. 2014;26(2):68-76
5. Turman KA, Diduch DR. Meniscal repair: indications and techniques. J Knee Surg. 2008 Apr;21(2):154-62.
6. Branch EA, Milchteim C, Aspey BS, Liu W, Saliman JD, Anz AW. Biomechanical comparison of arthroscopic repair constructs for radial tears of the meniscus. Am J Sports Med. 2015 Sep;43(9):2270-6
7. Fillingham YA, Riboh JC, Erickson BJ, Bach BR Jr, Yanke AB. Inside-Out Versus All-Inside Repair of Isolated Meniscal Tears: An Updated Systematic Review. Am J Sports Med. 2016 Mar 17. pii: 0363546516632504. [Epub ahead of print]
8. Nelson C.G., Bonner K.F. Inside-out meniscus repair. Arthrosc Tech. 2013 Nov; 2(4): e453–e460.
9. Bonner KF. Meniscus repair: Inside-out suture technique. In: Jackson DW, editor. Master techniques in orthopaedic surgery: Reconstructive knee surgery. Ed 3. Philadelphia: Lippincott, Williams & Wilkins; 2008:71-88.
10. Ritchie JR, Miller MD, Bents RT, Smith DK. Meniscal repair inthe goat model. The use of healing adjuncts on central tears and the role of magnetic resonance arthrography in repair evaluation. Am J Sports Med. 1998;26:278–84.
11. Zhang Z, Arnold JA, Williams T, McCann B. Repairs by trephination and suturing of longitudinal injuries in the avascular area of the meniscus in goats. Am J Sports Med. 1995;23:35–41.
12. Fox JM, Rintz KG, Ferkel RD. Trephination of incomplete meniscal tears. Arthroscopy. 1993;9:451–5.
13. Ra HJ, Ha JK, Jang SH, Lee DW, Kim JG. Arthroscopic inside-out repair of complete radial tears of the meniscus with a fibrin clot. Knee Surg Sports Traumatol Arthrosc. 2013;21:2126–2130
14. Horibe S, Shino K, Maeda A, Nakamura N, Matsumoto N, Ochi T. Results of isolated meniscal repair evaluated by second-look arthroscopy. Arthroscopy. 1996;12(2):150-155
15. Choi NH, Kim TH, Victoroff BN. Comparison of arthroscopic medial meniscal suture repair techniques: Inside out versus all-inside repair. Am J Sports Med 2009;37:2144-2150.
16. Grant JA, Wilde J, Miller BS, Bedi A. Comparison of inside-out and all-inside techniques for the repair of isolated meniscal tears: A systematic review. Am J Sports Med 2012;40:459-468.


How to Cite this article:. Tapasvi SR, Anshu S,  Patil SS. Inside-Out Meniscus Repair – A Review. Asian Journal of Arthroscopy  Aug – Nov 2016;1(2):14-18.

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All-Inside Meniscus Repair

William M Weiss, F. Alan Barber

Volume 1 | Issue 2 | Aug – Nov 2016 | Page 8-13


Author: William M Weiss[1], F. Alan Barber[2]

[1] Texas Tech University Health Sciences Center El Paso, Texas.
[2[ Plano Orthopedic Sports Medicine and Spine Center Plano, Texas.

Address of Correspondence

Dr William M Weiss
Texas Tech University Health Sciences Center Department of Orthopedic Surgery and Rehabilitation 4801 Alberta Avenue El Paso, Texas 79902.
E-mail: william.m.weiss@ttuhsc.edu


Abstract

 Meniscal surgery has undergone a considerable shift in goals over the last century. While early meniscal surgery consisted of mostly total meniscectomy, recognition of the importance of this structure resulted in a shift to partial meniscectomy, and then to repair in appropriate patients. The over-reaching goal is now the preservation of meniscal tissue to minimize the risk of osteoarthritis, particularly in the young athlete. Technologic advances in arthroscopy and instrumentation have allowed the development of minimally invasive techniques, which decrease the risks associated with open surgery. While no meniscal repair technique has been demonstrated to be superior in its outcomes, the all-inside technique requires no accessory incisions and minimizes the risk to posterior structures. While the early all-inside implants have been shown to risk chondral damage, the literature demonstrates that newer suture-based implants do not share these complications, and result in the healing of appropriate tears.
Key Words: All-inside, Meniscal tear, Meniscal repair, Chondral injury.


Introduction

The first open meniscal repair was performed in 1885 [1], though resection has been more common. With the advent of arthroscopy, minimally invasive techniques replaced open repairs, and provided better access to difficult areas while minimizing surgical risks. The inside-out suture repair was initially the described, and continues to be used with excellent results [2]. The outside-in repair was developed later to decrease risk of injury to posterior neurovascular structures [3]. In recent years, advances in instrument and implant technology have allowed the development of all-inside repair techniques. These rely on specialized implants, but avoid additional incisions, decreasing risk to posterior neurovascular elements, and reducing surgical times [4]. The purpose of this review is to examine the evolution of the all-inside meniscal repair technique, with outcomes and complications.

Meniscus Anatomy, Function, And Healing:
The menisci are crescent shaped fibrocartilaginous structures situated in both the medial and lateral compartments of the knee, between the femur and tibia. Each meniscus has an anterior and posterior horn, and is attached to the tibia by the anterior and posterior meniscal roots and to the peripheral capsule by the coronary ligaments. They are triangular in cross section, conforming to both the distal femur and proximal tibia. This conformity effectively deepens the articular surfaces of the knee, providing shock absorption and contributing to stability, particularly with injury to stabilizing ligaments. This also increases the surface area for load distribution to the articular cartilage, decreasing contact stresses by converting vertical compression stresses to radially oriented hoop stresses [5, 6]. By maintaining space in the joint, the meniscus improves diffusion of synovial fluid, and provides nutrition and lubrication to the cartilage. The healing capacity of the meniscus is determined primarily by blood supply, as it is largely avascular and does not typically heal spontaneously. The meniscus is divided into zones in accordance with blood supply and healing capacity. The peripheral third (within 3 mm of the meniscosynovial junction) is well vascularized, as the blood supply enters the here [7]. This zone is referred to as red-red, and is mostly likely to heal. The inner third (over 5 mm from the meniscosynovial junction) receives no vascular supply, is called the white-white zone, and is least likely to heal. The middle zone, called red-white (between 3 to 5 mm from the meniscosynovial junction), has some vascularity [7, 8]. Red-red zone tears are commonly repaired in appropriate patients, while repairs of red-white zone tears are less likely to heal.  Meniscal tear characteristics also influence healing potential. Longitudinal vertical tears (including bucket handle tears and meniscocapsular tears) have the capacity to heal with repair, while degenerative or complex (multi-planar), radial, horizontal, or flap tears are much less likely. Larger and less stable meniscal tears have higher failure rates, as have those repaired more than 8 weeks from injury [9]. Lateral compartment tears are also more likely to heal than those occurring medially [9]. This may be due to increased blood supply to the posterior horn of the lateral meniscus.

Meniscal Repair Technique
To overcome the inherent physiologic challenges of meniscal repair, the environment and technique must be optimized. Factors controlled by the surgeon include tissue preparation, the stability of fixation, knee stability and leg alignment, and post-operative rehabilitation. Preparation should include rasping of the tear, and the perimeniscal synovium. This stimulates the healing response [10], and can allow healing of isolated stable tears without fixation, particularly with concomitant ACL reconstruction [10,11]. Some advocate trephination to create vascular access channels, which may contribute to fibrovascular healing of avascular areas [12]. The addition of fibrin clot [13, 14], platelet-rich fibrin matrix [15], and collagen matrix with bone marrow [16] have been demonstrated to aid healing. Meniscal repair with associated ACL reconstruction improves healing, possibly by increasing blood in the joint, while lack of ACL function practically assures failure from stresses on the repair [17, 18]. ACL deficiency increased the failure rates of meniscal repair from 5% to 46% [19], demonstrating the importance of stability. Normal knee alignment also is required for successful meniscus repair outcomes. Forces within the knee, and through the meniscus, during normal gait can reach four times body weight and present significant challenges to fixation [20]. However, during unloaded knee motion the meniscus experiences only compressive forces [21, 22]. Therefore, fixation should maintain tissue approximation and neutralize sheer stresses. For suture-based repairs, vertically oriented non-absorbable sutures are considered the gold-standard, because of load to failure [23]. This configuration encircles the strong circumferential fibers, maximizing strength. Meniscus repairs are weak at the scar after 12 weeks 24, and visual evidence of healing at second-look arthroscopy has been seen at up to four months [25].

Surgical Technique Of Meniscus Fixation:
Arthroscopic techniques are the preferred method for meniscal repair; however no consensus exists as to the best technique. The most common indication for all-inside repair is tears of the posterior horn, as risk to neurovascular structures is decreased. All-inside repairs require less surgical time than other methods [26]. However, all-inside repairs do require an intact meniscal rim, highly specialized instruments, and implants. All-inside meniscal repair devices have progressed from rigid implants to current adjustable suture-based devices. Earlier versions of all-inside devices are no longer widely used or recommended. The adjustable suture-based all-inside devices are the state of the art.

Self-Adjusting Suture Containing Implants
The current generation of all-inside devices use ultra-high molecular weight polyethylene (UHMWPE) containing suture to connect typically non-absorbable poly ether-ether-ketone (PEEK) anchors. The suture is pre-tied, typically with a sliding and self-locking knot. Insertion instruments require only standard anterior portals, and often use a disposable cannula or a skid to aid passage. The meniscus repair device is inserted through the inner meniscus fragment to a pre-determined depth of the peripheral rim, often guided by the cannula. Once both anchors are deployed, the sliding-locking knot is cinched to compress the tear. This adjustability allows appropriate tensioning for reduction and healing, and the option to place horizontal, oblique, or vertical configurations.

figure-1-2-and-3

The FasT-Fix (Smith & Nephew, Andover, MA) was the first adjustable suture-based device (Fig. 1). It consisted of two 5 mm anchors, made of either poly L lactic acid (PLLA, absorbable) or polyacetal (nonabsorbable) connected by No. 0 non-absorbable braided polyester suture. The anchors are delivered by an instrument that is either straight or angled 22°. Once both anchors span the tear, the pre-tied sliding-locking knot is tensioned using a knot pusher/suture cutter. The original design was modified to become the Ultra Fast-Fix by reconfiguring the needle to facilitate insertion, and replacing the suture with a stronger No. 0 UHMWPE UltraBraid. The current iteration is the FasT-Fix 360 (Fig. 2), in which the anchors have been reconfigured to PEEK with an arrow design, and the suture is now No. 2-0 UltraBraid.

The RapidLoc (Mitek, Raynham, MA) was an adjustable suture-based device, consisting of a PLLA “backstop” and a PLLA or polydioxanone (PDS) “top hat”, connected by either a No. 2-0 absorbable Panacryl or non-absorbable braided polyester suture (Fig. 3). The “backstop” anchor was placed across the tear to be extra-capsular, and the pre-tied sliding knot and “top hat” was then advanced, compressing the tear. The instrument included straight, 12° and 27° angled needles.

The OmniSpan (Mitek, Raynham, MA) replaced the RapidLoc, and uses a loop of No. 0 OrthoCord (55% PDS and 45% UHMWPE) suture between two PEEK anchors (Fig. 4). The sliding-locking knot is outside the loop, reinforcing the first anchor, and forming a double suture repair without a knot on the articular surface. Both loops of the repair are tightened concurrently, allowing equal tension. This device allows sutures to be placed in both horizontal and vertical mattress fashion.

figure-4-and-5

The Meniscal Cinch (Arthrex, Naples, FL) has undergone incremental improvements since its inception (Fig. 5). The device is inserted with a 15° curved “gun” containing two separate trocar needles. It has an adjustable depth limiter on the handle, which is most commonly used at 18 mm. Each needle is loaded with a tubular PEEK anchor, and connected with a No. 2-0 FiberWire composed of UHMWPE and braided polyester (Arthrex Inc, Naples FL). The system includes a blue plastic “shoehorn” cannula to facilitate insertion, which is 6 mm in diameter and requires a large portal. The instrument allows placement of a vertical mattress stitch, secured with a pre-tied sliding-locking knot. After insertion, the first needle is removed and handed off. The second needle is “clicked” into position, and then a second device is inserted. Once both devices are deployed, the suture is gently pulled at the handle to tension the repair. A disposable knot pusher/suture cutter is provided.

The Sequent meniscal repair device (ConMed Linvatec, Largo, FL) utilizes No. 0 Hi-Fi (braided UHMWPE) suture with up to seven PEEK anchors measuring 1.3 mm in diameter and 5.1 mm long (Fig. 6). Each anchor is placed individually through the meniscus, with a straight or 15° curved instrument, and deployed on the extra-capsular surface. The suture is then tensioned to set the anchor into the tissue, and additional anchors can then be placed with the same device. A minimum of 3 anchors must be inserted to complete the repair, although more can be used to create an all-inside continuous stitch. This allows numerous stitch configurations, from continuous to interrupted stitches, and vertical or horizontal mattresses. This is the only device that can place multiple stitches without removal from within the joint. However, the technique is demanding, and practice in the laboratory prior to use is advised. The set includes a side-loading disposable suture cutter for use at completion.

figure-6-7-and-8

The MaxFire MarXmen (Biomet Sports Medicine, Warsaw, Indiana) is an self-adjusting all-inside all-suture implant with No. 0 MaxBraid PE (UHMWPE) and two braided polyester sleeves serving as anchors (Fig. 7). It is similar to the JuggerKnot all-suture anchor in design and function, but modified for the meniscus. The instrument uses a needle (straight or curved) to insert the suture and two polyester anchors through the meniscus. The sliding-locking knot allows tensioning, and devices can be placed in either a horizontal or vertical mattress fashion.

The CrossFix meniscal repair system (Cayenne Medical, Scottsdale, AZ) passes a No. 0 Force Fiber (UHMWPE) suture through two parallel 15 gauge hollow needles (straight or curved 12°, Fig. 8). Once the needles penetrate the meniscus, crossing the tear, a small shuttle passes the suture from one needle to the other on the extra-capsular surface. As the needles are withdrawn, a 3 mm horizontal mattress suture is left, and a pre-tied sliding Weston knot is advanced to secure the reduction. Additional arthroscopic knots can be added as reinforcement, if desired.

The AS (all suture) Repair device (Covidien, Minneapolis, MN) is similar to the CrossFix in design and function (Fig. 9). While the two needles are the same size, the AS repair device has conical solid needles with a polymer coat (NuCoat) to facilitate penetration. The instrument can be straight or curved 15°, and passes a No. 2-0 UHMWPE suture using a similar shuttle needle, but uses a modified Tennessee slider knot with two half hitches to secure the repair. Both instruments result in a 3 mm wide horizontal mattress, with a knot on the meniscal surface that risks chondral injury. Due to the instrument dimensions, only horizontal mattress sutures are possible. Conceptually, this newest generation of all-inside suture based devices allows improved reduction, tissue compression, and stability compared to previous iterations. The overall goal of all-inside meniscal repair devices is to decrease complications seen with the earlier generations, and promote healing. However, these devices can generate significant tension which may be detrimental, leading to implant failure. Few investigations regarding outcomes and complications of these adjustable all-inside suture implants are available in the literature.

figure-9

Results Of All-inside Meniscal Repair:
Arthroscopic meniscal repair methods have similar outcomes to open methods, with the gold standard inside-out suture repair having a success rate of 82% [17, 27], and outside-in suture repairs having success rates as high as 87% [28]. The original suture-based all-inside technique described by Morgan reported good results, but without any long term follow-up [29]. Early devices which rely on arthroscopic knot tying demonstrate up to 90% success initially, but this declines to 81% at 1 year [30].

Suture based implants have good strength, and are biomechanically equivalent to the gold standard vertical mattress sutures [31,32]. However, as this is the latest generation of all-inside devices, there is little long term outcome data available. The RapidLoc has demonstrated success rates of 86 to 91% [33, 34, 35], but there are reported failure rates of 35% [36] with complications reminiscent of rigid devices [37]. Longer term follow-up of these devices shows re-operation rates of 48% [38]. The FasT-Fix has also shown success rates from 82 to 92% [39,40], but with limited reports of complications. All-Inside devices have been demonstrated to have greater failure strength than inside out alternatives in the repair of radial meniscal tears [41].

Comparison Of Meniscal Repair Devices: Author’s preferred technique:
A human cadaver knee based comparison of several all-inside meniscus repair devices was carried out by the senior author to compare the technical ease, reproducibility, and consistency of using these devices in human meniscus tissue. A needle penetration depth limited to 18mm was found to be anatomically safe. Curved needles effectively reached the posterior horn with minimal articular cartilage injury. However, significant differences were observed in the technical ease, reproducibility, and consistency of all these devices. The FastFix 360 and OmniSpan were easiest to insert, least likely to excoriate articular cartilage, and most consistent in performance. Yet, the OmniSpan did not have any knot or device on the surface to later damage the articular cartilage. Based upon this data the author’s preferred technique uses the OmniSpan. The control provided by the gun allows for better positioning of the implants and decreased articular cartilage damage. Prototypes of the next generation of OmniSpan (the TrueSpan) perform even better but await clinical experience to confirm our expectations of superior performance.

Complications
All-inside meniscus repair has all the known risks and potential complications of knee arthroscopy. These occur in approximately 1% of patients, and include neurovascular injury, infection, and thrombophlebitis [42]. While neurovascular injuries are likely the most common complication of knee arthroscopy, when compared to other meniscal repair techniques the risk of this complication with all-inside repairs is decreased. Neurologic injury rates as low as 2% have been reported for all-inside techniques, in comparison to 9% for inside-out repairs [43]. The development of the all-inside technique was primarily to eliminate the need for accessory incisions and suture passing that are responsible for most of the neurovascular risk, so that repairs in the posterior horn can be done more safely. Injury to the saphenous nerve is most frequent, but as it is a sensory nerve this is often of little consequence [44]. Peroneal nerve palsy and popliteal artery pseudoaneurysm have also been reported 45, as have cases of cyst formation and synovitis [46, 47]. Complications associated with the adjustable-suture based current generation of all-inside devices include over penetration of the implant, loss of fixation, inadequate tension, and problems with implant deployment [48,49]. An overall complication rate for all-inside repair of 19% has been reported comparable to the gold standard [43]. The RapidLoc has caused cartilage injury in limited reports [50,37], and cadaveric studies have demonstrated placement of these implants may be challenging, but the significance of this is unclear [48,49]. Complications of all-inside repair can be minimized with detailed knowledge of anatomy, proper portal placement, measurement of meniscal depth, and placement of the indicated implant in an appropriate and secure manner.

Rehabilitation:
Post-operative rehabilitation following meniscus repair is highly variable between surgeons, with little consensus in the literature. Early knee motion is thought to be advantageous, as prolonged immobilization is known to lead to stiffness, atrophy, and impaired healing of the meniscus [51]. However, higher degrees of knee flexion cause considerable posterior translation of the femoral condyles, which increases forces within the meniscus and may stress repairs [52]. Weight-bearing can help reduce and stabilize longitudinal (bucket-handle) meniscus tears due to radially directed hoop-stresses [22], but loads with knee flexion cause increasing shear forces in the meniscus. These forces are increased almost four times with the combination of weight-bearing and flexion to 90 degrees [52].  Based on this information, weight-bearing in full extension poses little risk to repairs of longitudinal meniscal tears, and may aid with reduction and healing. However, for radial or meniscal root tear repairs (which are challenging with limited success), weight bearing is not advisable since circumferential fibers are not intact and the tear will be distracted. Accelerated rehabilitation programs designed to return patients to sport earlier have been described [53, 54], permitting early full weight bearing and unrestricted knee motion. The only limitations on return to sport in accelerated programs are the resolution of postoperative effusion, and return of full motion. Thus far, results of accelerated programs have shown return to sport without re-injury or complications. Meniscal repair in the setting of ACL reconstruction presents unique challenges. There is no evidence to support slowing ACL rehabilitation for an associated meniscal repair, and with the increased stability of new adjustable suture-based devices there is less reason to do so 55. The author’s current protocol for modern all-inside devices allows immediate range of motion from 0 to 90 degrees, immediate full weight bearing, early closed-chain strengthening, flexibility and endurance training. After 2 months, full flexion is allowed, and full return sport is permitted once the knee has no effusion, has regained full extension, and demonstrates flexion to greater than 135°.

Conclusions
Advances in arthroscopy and instrumentation technology have made all-inside meniscal repair popular and effective in appropriate meniscal tears. While no arthroscopic method has proven to have superior outcomes in the literature, all-inside methods are indicated for posterior horn meniscal tears to minimize the risk to neurovascular structures. The adjustable suture-based designs have so far demonstrated improved versatility and outcomes comparable to other methods. The versatility of these implants also allows their use in meniscal repairs that are not repairable by other methods, promoting the preservation of meniscal tissue when possible.


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12. Zhang Z, Arnold JA, Williams T, McCann B. Repairs by trephination and suturing of longitudinal injuries in the avascular area of the meniscus in goats. Am J Sports Med 1995;23:35-41.
13. Arnoczky SP, Warren RF, Spivak JM. Meniscal repair using an exogenous fibrin clot. An experimental study in dogs. J Bone Joint Surg Am 1988;70:1209-17.
14. Henning CE, Lynch MA, Yearout KM, et al. Arthroscopic meniscal repair using an exogenous fibrin clot. Clin Orthop Relat Res 1990;252:64-72.
15. Sgaglione NA. Meniscus repair update: current concepts and new techniques. Orthopedics 2005;28:280-6.
16. Piontek T, Ciemniewska-Gorzela K, Naczk J, et al. Complex Meniscus Tears Treated with Collagen Matrix Wrapping and Bone Marrow Blood Injection: A 2-Year Clinical Follow-Up. Cartilage 2016;7:123-39.
17. Cannon WD, Jr., Vittori JM. The incidence of healing in arthroscopic meniscal repairs in anterior cruciate ligament-reconstructed knees versus stable knees. Am J Sports Med 1992;20:176-81.
18. Hanks GA, Gause TM, Handal JA, Kalenak A. Meniscus repair in the anterior cruciate deficient knee. Am J Sports Med 1990;18:606-611.
19. Schmitz MA, Rouse LM, Jr., DeHaven KE. The management of meniscal tears in the ACL-deficient knee. Clin Sports Med 1996;15:573-93.
20. Morrison JB. Function of the knee joint in various activities. Biomed Eng 1969;4:573-80.
21. Richards DP, Barber FA, Herbert MA. Meniscal tear biomechanics: loads across meniscal tears in human cadaveric knees. Orthopedics 2008;31:347-50.
22. Richards DP, Barber FA, Herbert MA. Compressive loads in longitudinal lateral meniscus tears: a biomechanical study in porcine knees. Arthroscopy 2005;21:1452-6.
23. Starke C, Kopf S, Petersen W, Becker R. Meniscal repair. Arthroscopy 2009;25:1033-44.
24. Roeddecker K, Muennich U, Nagelschmidt M. Meniscal healing: a biomechanical study. J Surg Res 1994;56:20-27.
25. Morgan CD, Wojtys EM, Casscells CD, Casscells SW. Arthroscopic meniscal repair evaluated by second-look arthroscopy. Am J Sports Med 1991;19:632-637.
26. Barber FA, Coons DA. Midterm results of meniscal repair using the BioStinger meniscal repair device. Arthroscopy 2006;22:400-405.
27. Johnson D, Weiss WM. Meniscal repair using the inside-out suture technique. Clin Sports Med 2012;31:15-31.
28. Rodeo SA. Arthroscopic meniscal repair with use of the outside-in technique. Instr Course Lect 2000;49:195-206.
29. Morgan CD. The “all-inside” meniscus repair. Arthroscopy 1991;7:120-5.
30. Barrett GR, Treacy SH, Ruff CG. Preliminary results of the T-fix endoscopic meniscus repair technique in an anterior cruciate ligament reconstruction population. Arthroscopy 1997;13:218-23.
31. Borden P, Nyland J, Caborn DN, Pienkowski D. Biomechanical comparison of the FasT-Fix meniscal repair suture system with vertical mattress sutures and meniscus arrows. Am J Sports Med 2003;31:374-8.
32. Barber FA, Herbert MA, Richards DP. Load to failure testing of new meniscal repair devices. Arthroscopy 2004;20:45-50.
33. Quinby JS, Golish SR, Hart JA, Diduch DR. All-inside meniscal repair using a new flexible, tensionable device. Am J Sports Med 2006;34:1281-6.
34. Billante MJ, Diduch DR, Lunardini DJ, et al. Meniscal repair using an all-inside, rapidly absorbing, tensionable device. Arthroscopy 2008;24:779-85.
35. Barber FA, Coons DA, Ruiz-Suarez M. Meniscal repair with the RapidLoc meniscal repair device. Arthroscopy 2006;22:962-6.
36. Hantes ME, Zachos VC, Varitimidis SE, et al. Arthroscopic meniscal repair: a comparative study between three different surgical techniques. Knee Surg Sports Traumatol Arthrosc 2006;14:1232-7.
37. Barber FA. Chondral injury after meniscal repair with rapidLoc. J Knee Surg 2005;18:285-8.
38. Solheim E, Hegna J, Inderhaug E. Long-term outcome after all-inside meniscal repair using the RapidLoc system. Knee Surg Sports Traumatol Arthrosc 2016;24:1495-500.
39. Kalliakmanis A, Zourntos S, Bousgas D, Nikolaou P. Comparison of arthroscopic meniscal repair results using 3 different meniscal repair devices in anterior cruciate ligament reconstruction patients. Arthroscopy 2008;24:810-6.
40. Barber FA, Schroeder FA, Oro FB, Beavis RC. FasT-Fix meniscal repair: mid-term results. Arthroscopy 2008;24:1342-8.
41. Branch EA, Milchteim C, Aspey BS, et al. Biomechanical comparison of arthroscopic repair constructs for radial tears of the meniscus. Am J Sports Med 2015;43:2270-6.
42. Small NC. Complications in arthroscopic surgery performed by experienced arthroscopists. Arthroscopy 1988;4:215-21.
43. Grant JA, Wilde J, Miller BS, Bedi A. Comparison of inside-out and all-inside techniques for the repair of isolated meniscal tears: a systematic review. Am J Sports Med 2012;40:459-68.
44. Austin KS. Complications of arthroscopic meniscal repair. Clin Sports Med 1996;15:613-619.
45. Brasseur P, Sukkarieh F. [Iatrogenic pseudo-aneurysm of the popliteal artery. Complication of arthroscopic meniscectomy. Apropos of a case]. J Radiol 1990;71:301-4.
46. Choi NH, Kim SJ. Meniscal cyst formation after inside-out meniscal repair. Arthroscopy 2004;20:E1-3.
47. Kelly JDt, Ebrahimpour P. Chondral injury and synovitis after arthroscopic meniscal repair using an outside-in mulberry knot suture technique. Arthroscopy 2004;20:e49-52.
48. Miller MD, Blessey PB, Chhabra A, Kline AJ, Diduch DR. Meniscal repair with the Rapid Loc device: a cadaveric study. J Knee Surg 2003;16:79-82.
49. Miller MD, Kline AJ, Gonzales J, Beach WR. Pitfalls associated with FasT-Fix meniscal repair. Arthroscopy 2002;18:939-43.
50. Cohen SB, Anderson MW, Miller MD. Chondral injury after arthroscopic meniscal repair using bioabsorbable Mitek Rapidloc meniscal fixation. Arthroscopy 2003;19:E24-6.
51. Dowdy PA, Miniaci A, Arnoczky SP, Fowler PJ, Boughner DR. The effect of cast immobilization on meniscal healing. An experimental study in the dog. Am J Sports Med 1995;23:721-8.
52. Becker R, Wirz D, Wolf C, et al. Measurement of meniscofemoral contact pressure after repair of bucket-handle tears with biodegradable implants. Arch Orthop Trauma Surg 2005;125:254-60.
53. Barber FA. Accelerated rehabilitation for meniscus repairs. Arthroscopy 1994;10:206-10.
54. Mariani PP, Santori N, Adriani E, Mastantuono M. Accelerated rehabilitation after arthroscopic meniscal repair: a clinical and magnetic resonance imaging evaluation. Arthroscopy 1996;12:680-6.
55. Barber FA, Click SD. Meniscus repair rehabilitation with concurrent anterior cruciate reconstruction. Arthroscopy 1997;13:433-7.


How to Cite this article:. Weiss WM, Barber FA. All-Inside Meniscus Repair. Asian Journal of Arthroscopy  Aug – Nov 2016;1(2):8-13.

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Meniscectomy-Outcomes and Complications

Shantanu Sudhakar Patil, Sachin Ramchandra Tapasvi, Anshu Shekhar

Volume 1 | Issue 2 | Aug – Nov 2016 | Page 53-55.


Author: Shantanu Sudhakar Patil[1], Sachin Ramchandra Tapasvi[1], Anshu Shekhar[1].

[1] The Orthopaedic Speciality Clinic, 16 Status Chambers, 1221/A Wrangler Paranjpe Road, Pune 411004.

Address of Correspondence

Dr Sachin Ramchandra Tapasvi
The Orthopaedic Speciality Clinic, 16 Status Chambers, 1221/A Wrangler Paranjpe Road, Pune 411004
Email: stapasvi@gmail.com


Abstract

The menisci, once considered expendable remnants have been conclusively proven to be of extreme vitality in the biomechanics and biology of the knee joint. Though meniscus repair is being increasingly performed to preserve knee function, not all tears are amenable to repair and partial meniscectomy in such cases is an acceptable treatment option. The poor outcomes following partial meniscectomy are due to the shrinking of contact areas and rise in peak stresses. These changes and their consequences are more pronounced in the lateral compartment of the knee. Pre-existing chondral damage, instability and higher BMI compound the problem.
Key words: Meniscus, meniscectomy, meniscus repair, arthritis.


Introduction

The menisci of the knee joint are fibrocartilagenous semilunar tissues that perform a critical function of stabilising the joint and aiding in efficient load transfer as a shock absorber. Though once considered vestigial and hence disposable, the role of healthy menisci in delaying the normal attrition of the articular cartilage cannot be understated. Meniscectomy was thought to be a benign procedure and as late as 1975 [1] the importance of doing a complete removal was being reiterated. The functions of the meniscus were recognised much earlier [2] and eventually the potential harms of its excision were gaining attention. Meniscal tears are one of the commonest injuries of the knee, for which treatment is sought, with an incidence rate of 61 per 100000 population per year.[3] Most acute tears are commoner in younger patients, with the medial meniscus affected at a 2:1 ratio with the lateral side. The acute tears are described as per their orientation and extent along the meniscus. They are usually classified as vertical longitudinal, oblique, circumferential, complex, transverse or radial, and horizontal cleavage tears. Radial tears of the posteromedial compartment are the most frequently seen tears and vertical longitudinal tears are most often associated with acute ACL injury. Degenerative tears have a varied pattern and are complex in their morphology.[4]. The direction of the meniscus tears is explained by the orientation of collagen fibrils within the structure. The cross section of the meniscus reveals three distinct layers: a superficial thin layer on both tibial and femoral surfaces; a lamellar layer below this with the fibrils arranged in a radial manner and a main central region where the fibrils are orientated in a circular manner. The circular arrangement of the collagen bundles explains why majority of the tears have a longitudinal orientation. [5](Fig. 1). With our growing understanding of the anatomy , vasculature, biomechanics and the biology of the meniscus, and with improved arthroscopic techniques and instrumentation, the goal of management of meniscal tears has shifted towards achieving repair. However, not all tears are amenable to repair and at least a partial meniscectomy might be indicated to alleviate the patients symptoms. We will take a look at the outcomes and complications of arthroscopic meniscectomy in this article.

Sequelae of articular cartilage changes following Meniscectomy

The effects of meniscectomy on the stability and pressures inside the knee joint were studied using pressure sensitive films in cadavers. Medial meniscectomy caused the contact areas to shrink by almost 75% leading to more than twofold increase in peak contact pressures. [6] The articular cartilage responds unfavourably to the higher loads, with disruption of the proteoglycan matrix, causing swelling and inflammation throughout the joint. The heightened catabolic state with increased hydration leads to breakdown of the collagen matrix, thus accelerating the normal wear and tear within the joint.[7]

Radiological changes:
The radiological changes in the knee joint following medial meniscectomy are well documented.[8]Joint space narrowing, flattening of the marginal part of the medial femoral condyle and sclerosis of the articulating condyles is seen. These radiological signs were indicative of early osteoarthritic changes in the knee. Multiple clinical and radiological studies have documented these sequelae, but the correlation between the symptoms of the patient and severity of these changes is not always seen in the results. It is not easy to determine the correlations as many reports have studied the consequences after an open meniscectomy. Moreover, a meniscal tear rarely presents in isolation and the concomitant ligament or articular injuries play a role in subsequent degeneration and development of Osteoarthritis.

Partial Versus Total meniscectomy

With the advent of arthroscopic surgery and advances in instrumentation for the various surgical procedures, it was possible to resect only the offending parts of the torn meniscus. It is uncommon these days to perform a total resection, with partial meniscectomy being the more widely reported procedure. Once a meniscal tear is identified and deemed unsuitable for repair, a meniscectomy is the recommended surgical option. The basic principles for this were described by Metcalf. They are as follows: Remove all mobile fragments; Avoid sudden changes in rim contour; a perfectly smooth rim is unnecessary as some remodelling may occur; re-evaluate the tear often with a probe; Avoid damage to the meniscus-capsular junction to avoid the loss of hoop stresses; Use both manual and motorized instruments to maximize efficiency and when uncertain if an area should be resected, err on the side of leaving more meniscus intact rather than compromising biomechanical properties[9]. Salata in a meta-analysis showed the significantly higher risk of developing radiographic OA in the patients undergoing total meniscectomy as compared to the partial meniscectomy. [10] Though the patients with either partial or total meniscectomy report similar early clinical results, there was no significant difference in the radiographic outcomes at the final 7.8 years average follow-up[11]. Only 68% of the patients who had undergone a total meniscectomy and followed up for up to 30 years showed good or excellent results while at least 2/3rd had some post-operative symptoms.[12] There exists a direct correlation with the meniscal tissue left behind and peak contact stress on the tibial surfaces following partial resections[13]. A finite element study quantifying the amount of resected meniscus to peak pressures showed that with as little as 20% resection of meniscus, a detrimental increase of forces is seen which may hasten the osteoarthritic changes. Maximum shear stress in the articular cartilage is seen with 65% partial meniscectomy[14]. The orientation of collagen fibril bundles within the meniscus determines the development of hoop strains as they are axially loaded. A radial tear disrupts the continuity of the circularly oriented fibrils and thus prevents the hoop strains from forming, causing dysfunction of the meniscus. A horizontal or vertical tear will not disrupt this continuity, preserving the load-bearing and shock-bearing function of the meniscus.[15] This needs to be borne in mind while determining the extent of the meniscectomy. The medial and lateral tibio-femoral articulations are anatomically different and the absence of menisci which afford a degree of congruity can lead to increased point loading and higher contact pressures. This is more prominent on the lateral side where a convex lateral femoral condyle articulates on a flat or convex tibial plateau. This translates to poorer outcomes with lateral meniscectomy as compared to medial as reported in multiple studies. Patients with a lateral meniscectomy have a much higher functional deterioration and increased instability than the medial meniscectomy patients[11,3,16].

figure-1

Influence of other concomitant factors

The ACL-deficient knee with a meniscal tear has a significantly higher radiographic grade changes after meniscectomy as compared with ACL-intact knees.[17] Consequences of meniscectomy in an unstable knee are worsened by the combination of higher contact forces inducing early pathological changes due to the elevated shear stresses within the articular cartilage.[18] The presence of pre-existing chondral damage at the time of meniscectomy predisposes the knee to a significant increase in development of OA leading to poor clinical outcomes. However, contradicting findings have also been reported with there being no significant changes in knee functions and activity level following the meniscectomy. [19]. Chondral lesions can cause similar symptoms as that of a meniscal tear and meniscectomy may not fully alleviate the patients’ complaints, thus leading to poor outcomes. Degenerative tears are more often seen in older subjects with varus alignment. However, the evidence that meniscectomy in this group leads to higher rate of radiographic OA is not conclusive. These patients do show a decreased level of activity along with poorer outcomes based on subjective and functional measures following the surgery.[19, 20]While there is consensus about patients with increased BMI predisposing to a higher risk of OA post meniscectomy, the exact level of BMI that placed the patient at risk is not conclusive.[11], [21].

Complications

These can be classified as those related to knee arthroscopy in general and those associated specifically with arthroscopic partial meniscectomy. In the hands of an experienced arthroscopy surgeon, the complication rates were low. (1.78% and 1.48% for medial and lateral meniscectomy) [22], [23]. Some of the enumerated complications include instrument failure or breakage, injuries to nerves and blood vessels, accidental damage to chondral surfaces and ligament injury. Instrument failure rates have dropped from 18.1% to 2.9% over the years, due to improvement in surgical techniques, better designs as well as better skill levels of the surgeons[22]. The medial collateral ligament may get injured due to excessive valgus forces while attempting access to the medial compartment. Similarly, nerves and vessels may get damaged during insertion of sharp instruments. Improper and clumsy handling of instruments during the surgery can gouge the articular surface causing damage. Incomplete removal of the torn pieces can cause persistent pain along with coexistent knee pathology. Proper adherence to basic principles of partial meniscectomy can help avoid all these complications.

Conclusion

There exist a large number of studies which have studied the consequences of meniscectomy as a surgical procedure. Many of these have incomplete or inaccurate information along with varying heterogeneous criteria for evaluation of outcomes. The functional and clinical outcomes do not necessarily match the radiological outcomes in most of the studies. The multiple imaging modalities add to data which is not uniform for evaluation. This lack of homogenous data and lack of standardization of methodological issues, makes it difficult to conclude if the findings represent true differences or are simply artefact related to measurement bias or other errors. It is probably safe to conclude that a minimally invasive procedure with attention to sparing bulk of meniscal tissue seems to reduce the subsequent incidence of arthritic changes, as compared with open invasive and radical procedures..


References

1. Hughston, J.C., A simple meniscectomy. J Sports Med, 1975. 3(4): p. 179-87.
2. King, D., The healing of semilunar cartilages. 1936. Clin Orthop Relat Res, 1990(252): p. 4-7.
3. Jones, J.C., et al., Incidence and risk factors associated with meniscal injuries among active-duty US military service members. J Athl Train, 2012. 47(1): p. 67-73.
4. Pauli, C., et al., Macroscopic and histopathologic analysis of human knee menisci in aging and osteoarthritis. Osteoarthritis Cartilage, 2011. 19(9): p. 1132-41.
5. Petersen, W. and B. Tillmann, Collagenous fibril texture of the human knee joint menisci. Anat Embryol (Berl), 1998. 197(4): p. 317-24.
6. Baratz, M.E., F.H. Fu, and R. Mengato, Meniscal tears: the effect of meniscectomy and of repair on intraarticular contact areas and stress in the human knee. A preliminary report. Am J Sports Med, 1986. 14(4): p. 270-5.
7. Lanzer, W.L. and G. Komenda, Changes in articular cartilage after meniscectomy. Clin Orthop Relat Res, 1990(252): p. 41-8.
8. Fairbank, T.J., Knee joint changes after meniscectomy. J Bone Joint Surg Br, 1948. 30b(4): p. 664-70.
9. Metcalf, R.W., Arthroscopic meniscal surgery., in Operative Arthroscopy., M. JB, Editor. 1991, Raven Press: New York. p. pp. 203–236.
10. Salata, M.J., A.E. Gibbs, and J.K. Sekiya, A systematic review of clinical outcomes in patients undergoing meniscectomy. Am J Sports Med, 2010. 38(9): p. 1907-16.
11. Hede, A., E. Larsen, and H. Sandberg, Partial versus total meniscectomy. A prospective, randomised study with long-term follow-up. J Bone Joint Surg Br, 1992. 74(1): p. 118-21.
12. Tapper, E.M. and N.W. Hoover, Late results after meniscectomy. J Bone Joint Surg Am, 1969. 51(3): p. 517-26 passim.
13. Ihn, J.C., S.J. Kim, and I.H. Park, In vitro study of contact area and pressure distribution in the human knee after partial and total meniscectomy. Int Orthop, 1993. 17(4): p. 214-8.
14. Vadher, S.P., et al., Finite element modeling following partial meniscectomy: effect of various size of resection. Conf Proc IEEE Eng Med Biol Soc, 2006. 1: p. 2098-101.
15. Jones, R.S., et al., Direct measurement of hoop strains in the intact and torn human medial meniscus. Clin Biomech (Bristol, Avon), 1996. 11(5): p. 295-300.
16. Petty, C.A. and J.H. Lubowitz, Does arthroscopic partial meniscectomy always cause arthritis? Sports Med Arthrosc, 2012. 20(2): p. 58-61.
17. Burks, R.T., M.H. Metcalf, and R.W. Metcalf, Fifteen-year follow-up of arthroscopic partial meniscectomy. Arthroscopy, 1997. 13(6): p. 673-9.
18. McDermott, I.D. and A.A. Amis, The consequences of meniscectomy. J Bone Joint Surg Br, 2006. 88(12): p. 1549-56.
19. Rockborn, P. and J. Gillquist, Long-term results after arthroscopic meniscectomy. The role of preexisting cartilage fibrillation in a 13 year follow-up of 60 patients. Int J Sports Med, 1996. 17(8): p. 608-13.
20. Chatain, F., et al., The natural history of the knee following arthroscopic medial meniscectomy. Knee Surgery, Sports Traumatology, Arthroscopy, 2000. 9(1): p. 15-18.
21. Englund, M. and L.S. Lohmander, Risk factors for symptomatic knee osteoarthritis fifteen to twenty-two years after meniscectomy. Arthritis Rheum, 2004. 50(9): p. 2811-9.
22. Small, N.C., Complications in arthroscopic surgery performed by experienced arthroscopists. Arthroscopy, 1988. 4(3): p. 215-21.
23. Allum, R., Complications of arthroscopy of the knee. J Bone Joint Surg Br, 2002. 84(7): p. 937-45.
24. Papalia, R., et al., Meniscectomy as a risk factor for knee osteoarthritis: a systematic review. Br Med Bull, 2011. 99: p. 89-106.


How to Cite this article: Patil SS, Tapasvi SR, Shekhar A. Meniscectomy-Outcomes and Complications. Asian Journal of Arthroscopy  Aug – Nov 2016

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Menisci: Structure and Function

Ankit Chawla, Amite Pankaj Aggarwal

Volume 1 | Issue 2 | Aug – Nov 2016 | Page 3-7


Author: Ankit Chawla[1], Amite Pankaj Aggarwal[1]

[1] Unit of Joint Replacement, Arthroscopy and Orthopaedics, Fortis Hospital, Shalimar Bagh, New Delhi, India.

Address of Correspondence

Dr. Amite Pankaj Aggarwal
Fortis Hospital Shalimar Bagh
New Delhi, India.
Email: amitepankaj@gmail.com.


Abstract

Meniscal injuries are recognized as a cause of significant musculoskeletal morbidity. The menisci are vital for the normal function and long-term health of the knee joint. And loss of a meniscus increases the risk of subsequent development of degenerative changes in the knee. A review of anatomy and ultrastructure of the meniscus, and its relationship to normal function in terms of load transmission, shock absorption, joint stability, lubrication and nutrition is a necessary prerequisite to understanding pathologies associated with the knee.
Keywords: Meniscus, Medial meniscus, lateral meniscus, Anatomy, Function.


Introduction

The word meniscus comes from the Greek word me-niskos, meaning “crescent,” diminutive of me-ne-, meaning “moon.” The menisci are semilunar discs of fibrocartilaginous tissue which are vital for the normal biomechanics and long-term health of the knee joint [1]. The characteristic shape of the lateral and medial menisci is attained between the 8th and 10th week of gestation. They arise from a condensation of the intermediate layer of mesenchymal tissue to form attachments to the surrounding joint capsule[2,3].

Gross Anatomy
These crescent-shaped wedges of fibrocartilage are located on the medial and lateral aspects of the knee joint (Fig. 1A,1B). The peripheral, vascular border of each meniscus is thick, convex, and attached to the joint capsule. The innermost border tapers to a thin free edge. The superior surfaces of menisci are concave, enabling effective articulation with their respective convex femoral condyles. The inferior surfaces are flat to accommodate the tibial plateau [4,5].

Medial Meniscus
The medial meniscus is a C-shaped structure larger in radius than the lateral meniscus, with the posterior horn being wider than the anterior. The anterior horn is attached firmly to the tibia anterior to the intercondylar eminence and to the anterior cruciate ligament. The posterior horn is anchored immediately in front of the attachments of the posterior cruciate ligament posterior to the intercondylar eminence. Its entire peripheral border is firmly attached to the medial capsule and through the coronary ligament to the upper border of the tibia. At its midpoint, the medial meniscus is more firmly attached to the femur through a condensation in the joint capsule known as the deep medial collateral ligament [5]. The transverse, or “intermeniscal,” ligament is a fibrous band of tissue that connects the anterior horn of the medial meniscus to the anterior horn of the lateral meniscus [5,6].

Lateral Meniscus
The lateral meniscus is more circular in form, covering up to two thirds of the articular surface of the underlying tibial plateau [7]. The anterior horn is attached to the tibia medially in front of the intercondylar eminence, whereas the posterior horn inserts into the posterior aspect of the intercondylar eminence and in front of the posterior attachment of the medial meniscus. The lateral meniscus is loosely attached to the capsular ligament; however, these fibers do not attach to the lateral collateral ligament. The posterior horn of the lateral meniscus attaches to the inner aspect of the medial femoral condyle via the anterior and posterior meniscofemoral ligaments of Humphrey and Wrisberg, respectively, which originate near the origin of the PCL (Fig. 1A) [8]. Their estimated prevalence is 74 % for Humphrey ligament, 69 % for Wrisberg ligament, and both ligaments found together in around 50 % of knees [9]. The lateral meniscus is smaller in diameter, thicker in periphery, wider in body, and more mobile than the medial meniscus.

figure-1-and-2

Extracellular matrix and cellularity
Considering composition by wet weight, the meniscus has high water content (72 %). The remaining 28 % consists of an organic component, mostly ECM and cells.10 Collagens comprise the majority (75 %) of the organic matter, followed by GAGs (17 %), DNA (2 %), adhesion glycoproteins (<1 %), and elastin (<1 %) [10,11]. These proportions vary according to age, injury, or pathological conditions [12]. Collagen is the main fibrillar component of the meniscus. Different collagen types exist in various quantities in each region of meniscus. In the red–red zone, type I collagen is predominant (80 % composition in dry weight). In the white–white zone, 60 % is type II collagen and 40 % is type I collagen [13]. The major orientation of collagen fibers in the meniscus is circumferential; radial fibers and perforating fibers also are present.(Fig. 3) [13]. Proteoglycans are heavily glycosylated molecules that constitute a major component of the meniscus ECM [14]. These molecules are comprised of a core protein which is decorated with glycosaminoglycans (GAGs). The main types of GAGs found in normal human meniscal tissue are chondroitin 6 sulfate (60%), dermatan sulfate(20-30%), chondroitin 4 sulfate (10-20%), and keratin sulfate(15%) [15]. Their main function is to enable the meniscus to absorb water, whose confinement supports the tissue under compression [10]. Adhesion glycoproteins are also important components of the meniscus matrix, as they serve as a link between ECM components and cells [16]. The main adhesion glycoproteins present in the human meniscus are fibronectin, thrombospondin, and collagen VI [16,17]. Outer zone cells have an oval, fusiform shape and are similar in appearance and behaviour to fibroblasts, described as fibroblast-like cells [18]. The matrix surrounding the cells is mainly comprised of type I collagen, with small percentages of glycoproteins and collagen types III and V present. In contrast, cells in the inner portion have rounded appearance and are embedded in an ECM comprising largely type II collagen intermingled with a smaller but significant amount of type I collagen and higher concentration of GAGs [18]. This relative abundance of collagen type II and aggrecan in the inner region is more reminiscent of hyaline articular cartilage. Therefore, cells in this region are classified as fibrochondrocytes or chondrocyte like cells. In summary, cell phenotype and ECM composition render the outer portion of the meniscus akin to fibrocartilage, while the inner portion possesses similar, but not identical, traits to articular cartilage [19,20].

figure-3

Vascularity and Innervation
The vascular supply to the medial and lateral menisci originates predominantly from the lateral and medial geniculate vessels (both inferior and superior). Branches from these vessels give rise to a perimeniscal capillary plexus within the synovial and capsular tissue. (Fig. 2) Radial branches from the plexus enter the meniscus at intervals, with a richer supply to the anterior and posterior horns. Vessels supplying the body are limited to the meniscus periphery with a variable penetration of 10–30 % for medial meniscus and 10–25 % for lateral one. This has important implication for meniscal healing [21]. The remaining portion of each meniscus (65% to 75%) receives nourishment from synovial fluid via diffusion or mechanical pumping (ie, joint motion) [22, 23]. The knee joint is innervated by the posterior articular branch of the posterior tibial nerve and the terminal branches of the obturator and femoral nerves. The lateral portion of the capsule is innervated by the recurrent peroneal branch of the common peroneal nerve. These nerve fibers penetrate the capsule and follow the vascular supply to the peripheral portion of the menisci and the anterior and posterior horns, where most of the nerve fibers are concentrated. The inner menisci core has no nerve fibers [21].

Biomechanical Function
­­­The biomechanical function of the meniscus is a reflection of the gross and ultrastructural anatomy and of its relationship to the surrounding intra-articular and extra-articular structures. The meniscus withstands many different forces such as shear, tension, and compression. It also plays a crucial role in load-bearing, load transmission, shock absorption, stability, propioception as well as lubrication and nutrition of articular cartilage [24-27]. They also serve to decrease contact stresses and increase contact area and congruity of the knee [28,29].

Meniscal Biomechanics
The biomechanical properties of the knee meniscus are appropriately tuned to withstand the forces exerted on the tissue. Many studies have helped to quantify the properties of the tissue both in humans and in animal models. According to these studies, the meniscus resists axial compression with an aggregate modulus of 100-150 kPa [30]. The tensile modulus of the tissue varies between the circumferential and radial directions; it is approximately 100-300 MPa circumferentially and 10 fold lower than this radially [31]. Finally, the shear modulus of the meniscus is approximately 120 kPa [31]. The contact forces on the meniscus within the human knee joint have been mapped. It has been calculated that the intact menisci occupy approximately 60% of the contact area between the articular cartilage of the femoral condyles and the tibial plateau, while they transmit >50% of the total axial load applied in the joint [32,33]. However, these percentages are highly dependent on degree of knee flexion and tissue health. For every 30o of knee flexion, the contact surface between the two knee bones decreases by 4% [34]. When the knee is in 90o of flexion the applied axial load in the joint is 85% greater than when it is in 0o of flexion [33]. In full knee flexion, the lateral meniscus transmits 100% of the load in the lateral knee compartment, whereas the medial meniscus takes on approximately 50% of the medial load [29]. Studies confirm that there is a significant difference in segmental motion during flexion between the medial and lateral menisci. The anterior and posterior horn lateral meniscus ratio is smaller and indicates that the meniscus moves more as a single unit [35]. Alternatively, the medial meniscus (as a whole) moves less than the lateral meniscus, displaying a greater anterior to posterior horn differential excursion. Thompson et al found that the area of least meniscal motion is the posterior medial corner, where the meniscus is constrained by its attachment to the tibial plateau by the meniscotibial portion of the posterior oblique ligament, which has been reported to be more prone to injury [35,36]. A reduction in the motion of the posterior horn of the medial meniscus is a potential mechanism for meniscal tears, with a resultant “trapping” of the fibrocartilage between the femoral condyle and the tibial plateau during full flexion. The greater differential between anterior and posterior horn excursion may place the medial meniscus at a greater risk of injury [35]. The differential of anterior horn to posterior horn motion allows the menisci to assume a decreasing radius with flexion, which correlates to the decreased radius of curvature of the posterior femoral condyles [35]. This change of radius allows the meniscus to maintain contact with the articulating surface of both the femur and the tibia throughout flexion.

Load Transmission
Fairbank described the increased incidence and predictable degenerative changes of the articular surfaces in completely meniscectomized knees [37]. Weightbearing produces axial forces across the knee, which compress the menisci, resulting in “hoop” (circumferential) stresses [38]. Hoop stresses are generated as axial forces and converted to tensile stresses along the circumferential collagen fibers of the meniscus. Firm attachments by the anterior and posterior insertional ligaments prevent the meniscus from extruding peripherally during load bearing [39]. Medial meniscectomy decreases contact area by 50% to 70% and increases contact stress by 100%. Lateral meniscectomy decreases contact area by 40% to 50% but dramatically increases contact stress by 200% to 300% because of the relative convex surface of the lateral tibial plateau [40,41]. This significantly increases the load per unit area and may contribute to accelerated articular cartilage damage and degeneration [42].

Shock absorption
The menisci play a vital role in attenuating the intermittent shock waves generated by impulse loading of the knee with normal gait [43,44]. Voloshin and Wosk showed that the normal knee has a shock-absorbing capacity about 20% higher than knees that have undergone meniscectomy [38]. As the inability of a joint system to absorb shock has been implicated in the development of osteoarthritis, the meniscus would appear to play an important role in maintaining the health of the knee joint [45]

Joint stability
The geometric structure of the menisci provides an important role in maintaining joint congruity and stability. The superior surface of each meniscus is concave, enabling effective articulation between the convex femoral condyles and flat tibial plateau. When the meniscus is intact, axial loading of the knee has a multidirectional stabilizing function, limiting excess motion in all directions [46]. The studies for effects of meniscectomy on joint laxity for anteroposterior and varus-valgus motions and rotation have indicated indicated that the effect on joint laxity depends on whether the ligaments of the knee are intact and whether the joint is bearing weight. In the presence of intact ligamentous structures, excision of the menisci produces small increases in joint laxity. In an anterior cruciate ligament–deficient knee, medial meniscectomy has been shown to increase tibial translation by 58% at 90o, whereas primary anterior and posterior translations were not affected by lateral meniscectomy [47]. Shoemaker and Markolf demonstrated that the posterior horn of the medial meniscus is the most important structure resisting an anterior tibial force in the ACL-deficient knee. [48] Recently, Musahl et al reported that the lateral meniscus plays a role in anterior tibial translation during the pivot-shift maneuver [49].

Joint Nutrition and Lubrication
The menisci may also play a role in the nutrition and lubrication of the knee joint. The mechanics of this lubrication remains unknown; the menisci may compress synovial fluid into the articular cartilage, which reduces frictional forces during weightbearing [50]. There is a system of microcanals within the meniscus located close to the blood vessels, which communicates with the synovial cavity; these may provide fluid transport for nutrition and joint lubrication [51,52].

Conclusions
Mechanoreceptors have been identified in the anterior and posterior horns of the menisci, middle and outer third of the meniscus. The identification of these neural elements indicates that the menisci are capable of detecting proprioceptive information (joint motion and position) in the knee joint, thus playing an important afferent role in the sensory feedback mechanism of the knee [53,54].


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How to Cite this article:. Chawla A, Aggarwal AP. Menisci: Structure and Function. Asian Journal of Arthroscopy  Aug – Nov 2016;1(2):3-7 .

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Meniscal Scaffolds in the Clinics: Present and Future Trends

Ricardo Bastos, Renato Andrade, Hélder Pereira, J Miguel Oliveira, Rui L Reis, Scott Rodeo, João Espregueira-Mendes.

Volume 1 | Issue 2 | Aug – Nov 2016 | Page 47-52.


Author: Ricardo Bastos[1,2,3], Renato Andrade[2,3,4], Hélder Pereira[5,6,7,8], J Miguel Oliveira, Rui L Reis, Scott Rodeo, João Espregueira-Mendes[2,3,5,6,14].

[1] Universidade Federal Fluminense, Nireói, Rio de Janeiro, Brazil.
[2] Clínica do Dragão, Espregueira-Mendes Sports Centre – FIFA Medical Centre of Excellence, Porto, Portugal.
[3] Dom Henrique Research Centre, Porto, Portugal.
[4] Faculty of Sports, University of Porto, Porto, Portugal.
[5] 3B’s Research Group – Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark- Parque de Ciência e Tecnologia, 4805-017 Barco, Guimarães, Portugal.
[6]  – ICVS/3B’s – PT Government Associated Laboratory, Braga/Guimarães, Portugal.
[7] – Orthopaedic Department, Centro Hospitalar Póvoa de Varzim – Vila do Conde, Póvoa de Varzim, Portugal.
[8] – Ripoll y De Prado Sports Clinic FIFA Medical Centre of Excellence, Murcia-Madrid, Spain.
[9] – Co-Chief Emeritus, Sports Medicine and Shoulder Service, Hospital for Special Surgery, New York, USA.
[10] – Co-Director, Tissue Engineering, Regeneration, and Repair Program, New York, USA.
[11] – Orthopaedic Surgery, Weill Medical College of Cornell University, New York, USA.
[12] – Attending Orthopaedic Surgeon, Hospital for Special Surgery, New York, USA.
[13] – Head Team Physician, New York Giants Football, New York, USA.
[14] – Orthopaedics Department of Minho University, Minho, Portugal.

Address of Correspondence

Dr. João Espregueira-Mendes; Via Futebol Clube do Porto – F. C. Porto Stadium, Porto, Portugal; +351 220 100 100; Email: espregueira@dhresearchcentre.com


Abstract

Despite the high incidence, meniscal lesions still remain a clinical challenge due to its limited regenerative ability. In the last two decades, the development of scaffolding strategies has revolutionized meniscus treatment possibilities. Along with these new developments, the orthopaedic community has embraced the campaign “preserve the meniscus”. In this sense, acellular or cellularized scaffolds have emerged as a potential solution to treat irreparable meniscal lesions. Herein, it are overviewed the up-to-date acellular meniscal scaffolds used in the clinics, indications and discussed their outcomes.
Keywords: Meniscal scaffolds; Meniscal implants; Meniscal substitutes.


Introduction

The menisci have been described as a two-edge shaped semilunar discs of fibrocartilaginous tissue, found at the medial and lateral compartment of the tibiofemoral joint (1, 2). They play a fundamental role in many aspects of knee function, including articular congruency and stability, load distribution, shock absorption as well as a role in joint lubrication and proprioception (3). Many of these functions are achieved through the ability to transmit and distribute load over t The medial anhe tibial plateaus.d lateral menisci can transmit from 50% up to 70% of the load when the knee is in extension, and up to 85% at 90 degrees of knee flexion (4). Removal of the medial meniscus can result in a 50% to 70% reduction in femoral condyle cartilage contact area and a 100% increase in contact stress (5). Total lateral meniscectomy causes a 40% to 50% decrease in cartilage contact area and increases contact stress in the lateral compartment up to 200% to 300% of normal. Furthermore, even just partial removal of the meniscus does alter joint loading, particularly when two thirds of the posterior horn is excised (6). Despite the importance of the meniscus structure and the need for its preservation, meniscal lesions are the most common surgically treated knee pathology, and their annual incidence can be estimated at 60-70 per 100,000 knees, with 850,000 meniscal procedures performed yearly only in the United States (7) and 400,000 in Europe (8). For several years, the meniscus function was not fully understood. Recent pre-clinical and clinical evidences support the idea that the preservation of the meniscus structure is of outmost importance (9, 10). Thus, tissue engineering approaches have gain great attention as promise to regenerate different tissues and organs, including meniscus tissue (11-15). It has provided a fundamental understanding and technology that have permitted the development of scaffolds derived from biological tissues and synthetic materials, and there is currently a large amount of active, ongoing research into meniscus scaffolds (16-18). The meniscus scaffolds have been mainly limited to the treatment of meniscus partial repair once it requires an undamaged meniscal rim and enough tissue at the anterior and posterior horns to allow the fixation of the scaffold to the remaining meniscal tissues.

Types of Scaffolds

Scaffold biomechanical structure must have adequate material properties to allow tissue regeneration, while protecting the newly-forming tissue from excessive stresses. Their absorption must be sufficiently gradual, allowing appropriate cell migration, formation of new vessels, and matrix synthesis in order to create meniscal-like tissue (19, 20). At the same time, the scaffold and its degradation products should not damage the articular surface or invoke a foreign body reaction. An important step in the preparation of acellular meniscal scaffolds is the ability of mimicking the architectural and geometric complexity of the native tissue (20, 21). In this sense, it is crucial to further understand the menisci anatomy, biology, ultrastructure and biomechanical function to enhance the success of the meniscal substitution (1, 13). Two scaffolds are currently in clinical use.
Collagen Meniscus Implant (CMI, Ivy Sports Medicine GmbH, Germany) – First published in 1997, CMI is a type-I collagen (isolated and purified from bovine Achilles tendon) scaffold (22) to which glycosaminoglycans are added. It has a meniscus-like shape, is implantable arthroscopically, and it is biocompatible and biodegradable. It has a microscopic porous structure that allows cellular ingrowth, induces differentiation and proliferation of fibrocartilaginous cells, leading to the creation of a meniscus-like tissue, concomitant with gradual resorption of the scaffold. Nevertheless, collagen scaffolds are fragile during the implant procedure, and have shown a decrease in size on follow-up magnetic resonance image (MRI) and arthroscopic second look follow-up. The second type of scaffold is Actifit® (Orteq, United Kingdom) that has been developed to overcome the perceived limitations of CMI related to difficulties in tissue handling with respect to suturing during implantation (Figure 1). Actifit® is composed of a slowly degrading polymer with polycaprolactone and urethane segments (23). Its structure seems to have better mechanical properties and is more resistant to sutures and loads as compared to CMI. The scaffold is 80% porous; the remaining 20% are made of a polymer with a low absorption rate. Degradation starts with hydrolysis of polycaprolactone segments, which lasts up to five years; the polyurethane segments are removed by macrophages and giants cells or integrated into surrounding tissues (24, 25).

figure-1

Indications – Contraindications

When considering meniscal scaffolding, the surgeon should take into account several individual aspects, such as the patient’s age and weight, status of meniscal degeneration or concomitant conditions (such as axial malalignment and ligamentous insufficiency) (26). In this sense, several indications and contraindications have been developed as summarized in Table 1.

table-1

Preoperative Preparation

The preoperative imaging preparation usually involves radiography, MRI and, in some special cases, an arthro-computed tomography (arthro-CT). The radiographic imaging studies usually include bilateral comparison of weight-bearing radiographs (antero-posterior, lateral, Schuss or Rosenberg views). The MRI is usually performed to assess the cartilaginous structures status, quantify the meniscal damage, as well as the presence of bone marrow edema and/or meniscal extrusion (Figure 2). The arthro-CT scan may complement the MRI studies by assessing the meniscal volume and chondral damage (26). The imaging studies should be complemented with a comprehensive clinical examination of the knee. Special attention should be given to the knee ligament stability, as this has several implications in the meniscal surgery. In addition, diagnostic arthroscopy (Figure 3) may be performed to further assess the meniscal status and decide upon the best technique (26).

figure-2-and-3

Surgical Technique

The procedure can be performed arthroscopically using the two standard anteromedial and anterolateral portals. The portals should be enlarged for an easier passage of the scaffold. The native remaining meniscus is thoroughly evaluated, and any torn or degenerative tissue is removed in order to leave a healthy and uniform meniscal rim, ensuring that the resulting defect site extends into the vascularized red-on-red or red-on-white zone of the meniscus. The meniscal rim is punctured in order to create vascular access channels. Gentle rasping of the synovial lining may further stimulate meniscal integration and tissue ingrowth. The exact size of the defect is measure with a flexible rod loaded in a rigid cannula starting at the posterior end of the lesion. The scaffold is measured and trimmed to the correct size on the sterile field of the operating environment (10% larger than in situ measurement to compensate for the shrinkage caused by suturing of the sponge-like material and to assure a snug optimal fit into the prepared defect). In order to achieve a perfect fit of the scaffold with the native meniscus at the anterior junction, the anterior side should be cut at an oblique angle of 30°-45°. The implant is inserted into the defect (Figure 4). Standard arthroscopic meniscal suturing techniques may be utilized for scaffold stabilization. The authors prefer “all-inside” vertical stitches placed every 4 to 5 mm to suture the scaffold along the periphery. The anterior and posterior scaffold extremities are fixed to the native remnant with horizontal stitches.

figure-4

Concomitant Surgeries

Since other associated deficiencies (such as axial malalignment or ligamentous instability) may lead to poorer outcomes following meniscal surgery, these should be address in combination with the meniscal substitution (27).  Anterior cruciate ligament insufficiency, if not addressed, may result in residual laxity, which may lead to an unfavorable meniscal healing environment. In this sense, ACL reconstruction has been performed along with the meniscal substitution in up to 67% of the patients (28-30). When performing concomitant ACL reconstruction, the meniscal bed should be firstly prepared and then the tibial and femoral tunnels may be drilled. After the tunnels are drilled, the ACL graft is passed through the tunnels and fixed at the femoral site, as the meniscal scaffold is inserted and sutured. Subsequently, the ACL graft is fixed at the tibial site with 20° of knee flexion (31). When uncorrected axial knee malalignments are found, these should be concomitantly or previously corrected. In a varus malalignment situation, a high tibial osteotomy may be performed to correct the malalignment. Special attention must be directed to the tibial slope and proper release of the medial collateral ligament should be performed. In valgus malalignments, if the deformity does not involve the tibial bone, osteotomy is done on the femoral side to avoid joint line obliquity (27).

table-2

Rehabilitation protocol

Patients are required to undergo a conservative rehabilitation program similar to that for a meniscal allograft. Special attention is required when the meniscal scaffold is implanted with concomitant ACL reconstruction or realignment osteotomy. In these cases, a rehabilitation program should be tailored to comply with the concomitant procedures postoperative particularities (26, 27). General guidelines for the rehabilitation program are presented in Table 3.

Clinical Studies

Although the literature contains clinical studies (33-35) that support the use of meniscal scaffold implantation for the treatment of irreparable meniscal tears, the quality of the studies is generally low, with lack of randomized trials and long-term follow-up to confirm clinical benefit and the most appropriate indications. Furthermore, long-term follow-up studies are required to verify the protective effect on the damaged joint compartment exerted by meniscal scaffold implantation.
A recent systematic literature review (35) analyzed results and indications for the treatment of meniscal loss. There has been an increase in publications regarding this topic recently, and the authors concluded that both CMI and Actifit seem to be safe and positive results have been shown for both scaffolds.  Bulgheroni et al. (36) evaluated the safety and effectiveness of the polyurethane meniscal scaffold through clinical examination, MRI and arthroscopic second look, over a minimum two-year follow-up and showed no adverse reactions to the implant. The implant showed clear, hyperintense signal, sometimes irregular, and the chondral surface was preserved in all cases. At arthroscopic second look at 12 and 24 months, the scaffold was found to have an irregular morphology and to be slightly reduced in size. Zafagnini et al. (37), in a 10-year follow-up study, compared the medial collagen meniscus implant versus partial medial meniscectomy. The CMI group showed significantly lower visual analog scale scores for pain and higher objective International Knee Documentation Committee and Tegner index scores. Radiographic evaluation showed significantly less medial joint space narrowing in the CMI group compared to partial medial meniscectomy. No significant differences between groups were reported regarding Lysholm and Yulish scores.  Another long-term study compared outcomes of CMI versus partial meniscectomy in patients with concomitant ACL reconstruction. The authors concluded that patients with chronic meniscal tears treated with medial CMI reported lower levels of post-operative pain compared to meniscectomy, while acute lesions treated with CMI showed less knee laxity at follow-up (38). The CMI when performed in the acute setting showed no additional benefits when compared to partial medial meniscectomy alone (28).
Zafagnini et al. (39), in a multi-center study, evaluated the clinical outcomes of 43 patients after lateral CMI implantation. They reported improvement of all clinical scores from baseline to follow-up evaluations. At the final follow-up, 58% of the patients reported activity levels comparable to their pre-injury values, with 95% patient reported satisfaction. A higher body mass index, the presence of concomitant procedures, and a chronic injury pattern were identified as potential negative prognostic factors.
As far as concomitant open-wedge high tibial osteotomies is concerned, Gelber et al. (40) found no short-term additional benefit when compared to partial meniscectomy and meniscal scaffolding.

Final Remarks and Future Directions

The menisci are known to be heterogeneous complex structures with segmental variations according to their anatomy, biology and function. The proper understanding on the different types of meniscal injuries (both traumatic and degenerative) and their pathophysiology and pathomechanics will assist the clinician in identifying the correct indications and contraindication for each type of lesion, preserving the meniscus whenever possible.  The clinical application of meniscal scaffolds is limited to CMI and Actifit. In order to successfully implant these meniscus scaffolds, it is required an intact meniscal rim and sufficient meniscal tissue at the anterior and posterior meniscus horns to attach the scaffold. When in case of axial malalignments and/or ligament insufficiencies, these must be correct prior or during the scaffold implantation. The rehabilitation protocol should be tailored to address each patient’s individual characteristics, respect the chronobiology of the scaffold tissue integration and the progression within phases should be goal-based. Novel meniscal scaffolds have been developed for addressing total meniscus reconstruction with a functional meniscus replacement, mimicking the biology and mechanical properties of the native meniscus. These novel scaffolds may further protect the articular cartilage surface of the knee joint from the extensive damage after a total meniscectomy. A second generation of implants pre-cultured in vitro allows cell adhesion and extracellular matrix production and then are implanted into the meniscal defects which will probably follow as cell seeding as has been demonstrated to improve the mechanical properties and histological results. In the future, it may be possible to improve tissue formation in the meniscal scaffold using autologous cells (e.g., stem cells) and/or growth factors (e.g., platelet-rich plasma). This strategy may augment the tissue regeneration and improve clinical results. The use of mesenchymal stem cells may also enhance a greater promotion of intrinsic meniscal healing capacity. In addition, nanotechnology and gene therapy have emerged as potential options and have showed great potential for the treatment of meniscal lesions, however its translation into the clinical setting may take a few more years. Biofabrication of patient-specific meniscal scaffolds with a 3D printer from the advanced segmentation of menisci knee MRI datasets has been showing promising results in the laboratory setting. This novel technique will allow tailoring the meniscal scaffold to the patient-specific native characteristics of the knee.


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How to Cite this article: Bastos R, Andrade R, Pereira H, Oliveira JM, Reis RL, Rodeo S, Espregueira-Mendes J. Meniscal Scaffolds in the Clinics: Present and future trends.Asian Journal of Arthroscopy  Aug – Nov 2016;1(2):47-52 .

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Asian Journal of Arthroscopy – Vision for Tomorrow

Sachin Tapasvi, Parag Sancheti, Ashok Shyam

Volume 1 | Issue 2 | Aug – Nov 2016 | Page 1-2


Author: Sachin Tapasvi [1], Parag Sancheti [2] , Ashok Shyam [2],[3]

[1]  Orthopaedic Specialty Clinic, Pune Maharashtra.
[2] Sancheti Institute for Orthopaedics & Rehabilitation, Pune, India
[3]  Indian Orthopaedic Research Group, Thane, India

Address of Correspondence

Dr Ashok Shyam
AJA Editorial Office, A-203, Manthan Apts, Shreesh CHS, Hajuri Road, Thane [w], Maharashtra, India.
Email: editor@asianarthroscopy.com


The first Issue of Asian Journal of Arthroscopy was launched in Pune, India at the hands of Dr Ramchandra Tapasvi, Dr João Espregueira-Mendes, Dr David Parker, Dr Sachin Tapasvi and Dr Parag Sancheti. The first issue had a symposium on graft selection for ACL reconstruction with contributions from both international and national surgeons. We have received many positive response and also comments to improve on the format of the journal, but in the end, AJA has successfully piqued the interest of Arthroscopy Surgeons all across the globe. Surgeons have commented on the quality of the articles, on the review process and specially on indexing of the Journal. With these expectations, the responsibility of the editorial team has greatly increased to maintain the best standard for the Journal.  We have identified the main areas of focus that will help AJA evolve into a truly international Journal. One of the most important aspect will be dedicated symposia on a focussed topic in each issue.

launch-of-asian-journal-of-arthroscopy

The current issue contains symposium on meniscal tears and again has contributions from various teams of surgeons. These symposiums basically reflect a combined approach of elaborating personal experiences along with literature review to provide readers with a practical and clinical article that is free of statistical aspect of the current review papers. The focus is on the surgical decision making, surgical techniques and tips and tricks of the surgery. We believe this combination provides the best reading material to practicing surgeons as well as trainees of Arthroscopy. We shall definitely continue this tradition of dedicated symposia in future. The forthcoming symposium is on shoulder instability and Dr Jonathan Herald from Sydney Australia will be the guest editor for the issue. The second focus area is collecting surgical videos and techniques. Arthroscopy is a branch which is much more visual than theoretic and videos are the best form of visual aid that an academic journal can provide. We will be creating a separate section which will look after this aspect of video articles and we invite our readers to submit their surgical videos for publication in AJA. The third area is peer review, which is the main academic backbone of any journal. AJA has a policy of blinded peer review and every article will be sent for peer review to at least three reviewers. This may take some time, as we have less number of reviewers currently, but we request our authors to be a bit patient with us. We will also request all our authors and readers to join us a reviewers also. They can do so easily by creating an account in ‘scripture’ and adding reviewer to the profile. The review process will be exclusively through the online journal system and all records will be saved for future references. We also offer our reviewers a certificate for reviewing articles and publish their names in the first issue of every year. The last focus area is indexing of the Journal, which we are trying to push aggressively. The journal has received the ISSN number and copy of the first issue has been submitted to various indexing bodies. However we know that all indexing bodies will take time for assessment of the journal and real Indexing and assessment of journal will only be at the end of successful two years of the Journal. The steps toward fulfilling all criteria’s for major indexes are actively taken from the first issue itself.  The editorial board of AJA firmly believes in the idea and concept of AJA and we the support of our readers, authors, and reviewers we believe we can make AJA the very best in the world.

Dr Sachin Tapsvi | Dr Parag Sancheti | Dr Ashok Shyam


How to Cite this article: Tapasvi S, Sancheti PK, Shyam AK. Asian Journal of Arthroscopy – Vision for Tomorrow. Asian Journal of Arthroscopy  Aug – Nov 2016;1(2):1-2.

Dr. Sachin Tapasvi

Dr. Sachin Tapasvi

Dr. Parag Sancheti

Dr. Parag Sancheti

Dr. Ashok Shyam

Dr. Ashok Shyam


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