1 Introduction

Meniscus tears during sports injuries have been reported to be accompanied by rupture of ACL in more than 80% of cases.¹ It has now been well-established that menisectomy leads to the development of premature osteoarthritis.² In recent times hence there has been a shift in focus from meniscus resection to its preservation and repair.³

However repair of meniscus tear in association with elective ACL reconstruction remains vogue. Majority of these patients undergo late ACL reconstruction for instability, meniscus tear are usually asymptomatic and present for a longer period of time before surgery. Due to the chronicity of the tear, meniscus repair may potentially have poor healing.⁴ The objective of our study was to assess success of meniscus repair performed in association with elective ACL reconstruction in our department.

2 Patients and methods

We performed a retrospective review over 3 years' duration (Jan 2009 to Dec 2013) in a large teaching hospital. Inclusion criteria were all consecutive patients who underwent meniscus repair with ACL reconstruction. Exclusion criteria were patients with isolated meniscus injuries, multi-ligamentous injury and associated fractures.

The data was collected through patients' case notes and included demographic details, mechanism of injury, symptoms and their duration, details of meniscus tear (medial or lateral), grade of surgeon, postoperative rehabilitation regimen, concurrent surgical procedure, recurrent symptoms and subsequent surgery performed. Meniscus tear was grouped as per size (>or <3cm), type of tear (i.e. bucket handle, radial, etc) and location – Zone 1 to 3 (Cooper).

All our patients had arthroscopic meniscus repair performed using FasT-Fix anchors (Smith & Nephew). Only meniscus which were suitable for repair; i.e. not degenerate, reducible, no rolled margins and able to perform a sound repair, underwent meniscus repair.⁴

All-inside technique was used in all our patients. Postoperatively, range of knee flexion was limited from 0 to 90° using an off the shelf knee brace for 6–8 weeks in order to protect the repaired meniscus and gradual rehabilitation with physiotherapy. Patients were followed up at 6 weeks; 3 months and 9 months as a routine post operative follow up after ACL reconstruction.

For the purpose of this study, patients without further clinical symptoms (pain, swelling and locking) or radiological sign (CT or MRI) or arthroscopic evidence of failed repair at follow up were regarded as successful repair.⁵ Partial healed meniscus with clinical symptoms were regarded as failed repair. All patients were allowed to perform normal activities including sports at 9 months. We used Fisher's exact test for statistical analysis of our results.

3 Results

87 meniscus repairs were performed in association with ACL reconstruction during our study period. 2 patients were lost to follow up (less then 9 months) and were excluded from the study leaving only 85 patients for the purpose of this study. Average age 25.9 years (ranged from 15 to 48 years). There were 66 male and 18 female patients. Average time of follow up from the time of surgery was 11 months average (range 9–16 months) (Table 1).

Off the 85 patients, majority of our patients (75% n=64) presented late (after 2 weeks) after injury and subsequently underwent meniscus repair with ACL reconstruction (Group 1). 21 patients had meniscus repair with ACL reconstruction within 2 weeks of injury (Group 2-control group) (Table 1). Main symptoms at the time of initial presentation included pain (74%), instability (69%), swelling (68%) and mechanical locking (8%).

Mechanisms of injuries included sports-related accidents in 58% cases (football, rugby, cricket) followed by falls (26%) and road traffic accidents (5%), while 5% had no history of specific trauma.

18 patients had ongoing or recurrent symptoms (pain, swelling or locking). Subsequent radiological investigation (CT arthrogram or MRI) showed failed repair in 16 patients. 14 of these patients later underwent arthroscopic partial resection of the meniscus whilst 2 had partially healed meniscus, which was treated conservatively. Other 2 patients, with negative radiological investigations, subsequently clinical symptoms resolved with physiotherapy (Table 1).

Patients in Group 1 (elective ACL reconstruction) had 23% (n=15) failure rate compared to Group 2 (control group), which was 4.8% (n=1). Patients with delayed meniscus repair had a significantly higher failure rate (p<0.048) (Table 1).

4 Discussion

Meniscus repairs performed in conjunction with ACL reconstruction generally are thought to have better healing rate than meniscus repairs in knees with intact ACLs.⁶ Warren etal in their study reported that the success rate of meniscus repair with ACL reconstruction could be up to 90% while the failure rates were found to be 30%–40% if the knee remains unstable due to ruptured AC.⁷

With the stabilization of the knee after ACL reconstruction, the inciting cause for the repeated micro trauma of the menisci is eliminated, or at least diminished. Moreover, marrow elements are introduced into the joint cavity with the ACL procedure are thought to modulate the healing response of meniscus fibrochondrocytes.^8,9

In this study, delayed meniscus repair associated with elective ACL reconstruction had a significant higher failure rate (Table 1). Chronicity of the tear, which is associated with avascularity and poor opposing margins of the meniscus edges, may explain the poor healing potential.⁴ There have been no randomized studies that have investigated the outcome of meniscus repair in relation to the ACL state. There are some studies that comprise subgroups of patients with either ligamentous intact, reconstructed, or unstable knees. In the majority of these studies, it seems that the outcome of a repair is better with concomitant reconstruction than in knees that remain unstable or even better than knees without ACL injury.^10–15

It must be assumed that in the subgroup of patients with concomitant ACL reconstruction, the main reason for the procedure is instability, and that conclusively not only symptomatic but also clinically silent lesions of the meniscus are identified and repaired. However, in patients with stable knees, the cause for the meniscus repair usually is meniscus symptoms, such as locking or effusion. The possibility of a selection bias must therefore be considered.

There is no single accepted definition for ‘failure of meniscus repair’ exists in the current literature. Noyes etal defined the ‘failure of the repair’ as persistence of symptoms (swelling, locking, or joint pain) and/or the requirement for repeat knee arthroscopy and meniscectomy.¹⁶ Some studies have found that on repeat arthroscopy, the menisci can be partially healed in the absence of clinical symptom.¹⁷ Using clinical symptoms as a tool to assess the healing status provides only an indirect evidence of successful healing. However, we used resolution of clinical symptoms as successful meniscus repair as routine repeat arthroscopy to assess meniscus healing is not feasible in clinical practice. In addition, the patients may also not want to be followed up once their symptoms have settled after successful surgical management.¹⁶

Cannon and Vittori found lateral menisci to have a better healing rate than medial menisci.¹⁸ Another investigation into ACL-reconstructed knees did not find different failure rates for lesions located in the Cooper zones 1 and 2 of either the medial or lateral meniscus.¹⁹ It is not entirely clear whether or not the healing potential in the medial and lateral meniscus are different. Yet the potential sequelae of meniscectomy are more serious in the lateral meniscus than in the medial.²⁰ Therefore, in the decision-making process, it matters which of the menisci is affected. Our clinical results showed a successful repair of 86% which comparable to previous studies.^6,21–23 There were less failure rate in cases of lateral meniscus repairs (4%) and 23% for medial meniscus repair.²⁴

The available literature suggest there are other potential factors influencing the outcome meniscus repair including type of tear, zone of injury, age of patient and chronicity of tear may influence the outcome of meniscus repair.^19,25 In this study, subgroup analysis, did not show that the size of tear or type of tear or the zone of tear influenced the outcome of the meniscus repair. However due to the small number of subgroups in this study we feel there might have been no association.

The prognosis of a meniscus repair has a favourable outcome, if it is possible, for early referral and appropriate management of these injuries. Meniscus preservation has gained a high level of awareness in the recent years. The surgeon must consider the nature of the tear in his decision of whether or not to repair or resect.

5 Conclusion

Our results have shown that the outcome of meniscus repair was found to be more successful and statistically significant if repaired early. However the considering the important role of meniscus in maintaining knee function and in preventing arthritis, meniscus preservation surgery should be considered whenever possible, especially in cases of younger patients and lateral meniscus tears.

Conflicts of interest

All authors have none to declare.