Not all meniscal repair failures are equal: A comparison between early and late failure risk factors.

Purpose: Meniscal repair failure is a significant clinical concern, but existing literature treats it as a single outcome without differentiating timing. Early and late failures may represent mechanistically distinct phenomena; identifying their differential predictors could improve risk stratification and postoperative monitoring. Methods: A retrospective cohort study used a national database to identify patients undergoing arthroscopic meniscal repair, including both isolated repairs and repairs performed with concomitant anterior cruciate ligament reconstruction, classified into early failure (reoperation <365 days, approximating the conventional period of meniscal healing), late failure (≥365 days) or no failure. Cause-specific Cox proportional hazards regression identified independent predictors of each failure type separately. Results: Of 38,003 patients, 3399 (8.9%) experienced failure (1996 early; 1403 late). A bimodal hazard pattern supported phenotypic distinction between groups. Early failure was independently predicted by female sex (hazard ratio [HR] 1.15), bucket-handle tear (HR 1.30), traumatic mechanism (HR 1.14), concomitant microfracture (HR 1.54), hamstring autograft (HR 1.21) and single-anchor repair (HR 1.28); three or more anchors were protective (HR 0.83). Late failure was uniquely predicted by knee osteoarthritis (HR 1.33), whereas increasing age was independently protective (HR 0.98/year) as well as three or more anchors (HR 0.86). Among isolated meniscal repairs, partial meniscectomy was the most common reoperation in both groups, but more frequent in late failures (60.1% vs. 53.7%). Re-repair was more common after early failure (22.5% vs. 16.1%), while TKA was more prevalent after late failure (9.8% vs. 5.4%). All reported associations and between-group differences were statistically significant ( Conclusion: Early and late meniscal repair failures are distinct clinical phenotypes with differing risk factors and reoperation patterns. Early failure appears driven by mechanical and technical factors; late failure is more strongly associated with degenerative joint disease and host biology. These findings may inform individualised monitoring and risk stratification strategies. Level of Evidence: Level III, retrospective cohort study.