Purpose: The aim of this study was to evaluate the incidence of failure of anterior cruciate ligament (ACL) reconstruction and to assess the prognostic factors for such an outcome.
Methods: A prospective inception cohort of patients undergoing ACL reconstruction was analysed for failure (patient reported symptoms of rotational instability, a clinically positive pivot shift, MRI or arthroscopy showing ACL graft rupture). Risk factors evaluated included medial and lateral meniscal deficiency, medial and lateral meniscal repair, age, gender, BMI, graft size and time to surgery. Survival analysis was performed using the Kaplan-Meier method. Prognostic factors were assessed using the Cox proportional hazard model to investigate whether covariate risk factors influenced graft survival.
Results: One hundred and twenty-three patients were available for final analysis at a follow-up of 2 years. Eighteen patients satisfied the criteria of failure (15.4 %). Risk factors for failure were medial meniscal deficiency (hazard ratio 4.5; 95 % CI 1.8-11.5; p = 0.002), or lateral meniscal deficiency (hazard ratio 3.5; 95 % CI 1.3-9.3; p = 0.01). At 2-year follow-up, ACL survival was 94.5 % (95 % CI 89-100) for patients with intact menisci and 69 % (95 % CI 56-86) for those with deficiency of the medial or lateral meniscus (log-rank test p = 0.017). Patients were 4.9 times more likely to fail if they had a deficient medial or lateral meniscus. Those patients who underwent meniscal repair did not demonstrate any increased risk of failure.
Conclusion: Medial and lateral meniscal tears are important prognostic factors that influence the survival of ACL reconstruction. Surgeons should endeavour to repair all meniscal tears associated with ACL reconstruction.
Level of evidence: II.
Keywords: Anterior cruciate ligament; Meniscus; Risk factors.