Failure and complication rates following meniscal all-inside and inside-out repairs: A systematic review and meta-analysis.

Purpose: This study examines failure rates, complication rates and patient-reported outcome measures (PROMs) for meniscal all-inside (AI) and inside-out (IO) repair techniques.

Methods: A systematic search was conducted on PubMed, Embase and Cochrane (inception to January 2024) assessing for Level I-III studies evaluating outcomes after meniscal repair. The primary outcome regarded differences in failure rates between AI and IO repair techniques. Secondary outcomes included a comparison of complication rates and PROMs. Quality assessment was performed using the Grading of Recommendations Assessment, Development and Evaluation and Methodological Index for Non-Randomized Studies criteria. A meta-analysis was conducted for outcomes reported by more than three comparative studies.

Results: A total of 24 studies (13 studies and 912 menisci for AI vs. 17 studies and 1,117 menisci for IO) were included. The mean follow-up ranges were 22-192 months (AI) and 18.5-155 months (IO). The overall reported AI failure rate ranged from 5% to 35% compared to 0% to 25% within the IO group. When comparing meniscal repair failure rates in the setting of concomitant anterior cruciate ligament reconstruction, the AI group had a failure rate (AI: 5%-34%; IO: 0%-12.9%). The complication rate ranged from 0% to 40% for AI and 0% to 20.5% for IO. Post-operative PROM scores ranged from 81.2 to 93.8 (AI) versus 89.6 to 94 (IO) for IKDC and 4.0-7.02 (AI) versus 4.0-8.0 (IO) for Tegner. Upon pooling of six comparative studies, a significantly lower failure rate favouring the IO technique was observed (15.9% AI vs. 11.1% IO; p = 0.02), although this result was influenced by a study with a predominantly elite athlete population. Moreover, no significant differences were found regarding complication rates between cohorts (7.3% AI vs. 4.8% IO; p = 0.86).

Conclusion: The present study underscores comparable clinical success between AI and IO meniscal repair techniques, with both techniques demonstrating similar complication rates. However, the AI repair technique was associated with 1.77 times higher odds of failure compared to the IO cohort.

Level of evidence: Level III.