Preoperative joint effusion and varus malalignment predict early clinical failure after arthroscopic meniscal repair for degenerative medial meniscal tears: A retrospective multicenter cohort study.

BACKGROUND

Degenerative medial meniscal tears (DMMTs) pose challenges in surgical management, with varying repair outcomes. This study aimed to identify preoperative factors associated with early clinical failure after isolated arthroscopic meniscal repair of DMMTs.

METHODS

This study retrospectively reviewed data from patients (mean age, 49.0 ± 9.1 years) who underwent isolated all-inside medial meniscal repair at two institutions (2018-2025). The evaluated potential predictors included patient characteristics (demographics, symptom duration), radiographic alignment measures (Kellgren-Lawrence grade, percentage of the mechanical axis [%MA] as a continuous variable, and %MA<30 % as a categorical cutoff, medial proximal tibial angle), magnetic resonance imaging findings (joint effusion, defined by an effusion-synovitis score of ≥1 based on the magnetic resonance imaging Osteoarthritis Knee Score; cartilage damage; bone marrow lesions), and meniscal tear features (location, morphology). Significant variables identified through univariate analysis were included in the multivariate logistic regression.

RESULTS

Forty-three knees were analyzed (23 successes [54 %], 20 failures [46 %]). The Kellgren-Lawrence grade based on preoperative radiographs was distributed as follows: 0/1/2 = 9/26/8. On preoperative MRI, cartilage damage was observed for 14 knees (32.6 %). Failures had a higher prevalence of preoperative effusion (85.0 % vs 30.4 %, p = 0.001) and lower mean %MA (36.8 ± 12.3 vs 44.7 ± 12.0, p = 0.036). %MA<30 % was more frequent among failures (40.0 % vs 8.7 %, p = 0.028). Multivariate analysis identified preoperative effusion (odds ratio [OR]: 17.7, 95 % confidence interval [CI]: 3.6-178.0, p < 0.001) and %MA<30 % (OR: 12.4, 95 % CI: 1.8-166.6, p = 0.008) as independent predictors of failure.

CONCLUSIONS

Preoperative joint effusion and varus malalignment (%MA<30 %) were significant predictors of early clinical failure 6 months after isolated arthroscopic meniscal repair for DMMTs.