Female Sex, High Body Mass Index, More Pronounced Femoral Chondral Injury, and Poor Rehabilitation Compliance Were Associated With Medial Meniscus Posterior Root Tears Repair Failure

Purpose To evaluate the risk factors for failure of medial meniscus posterior root repairs, including the preoperative patient factors, surgical factors, and compliance with rehabilitation, excluding already known factors of failure such as uncorrected varus axis deviation and advanced degenerative changes in the medial compartment. Methods Patients who underwent transtibial pullout repair for medial meniscus posterior root tears with ≥24 months’ follow‐up were included. Variables analyzed included demographics, time from injury to surgery, Kellgren‐Lawrence and Outerbridge grades, surgical details, concomitant osteotomy or medial compartment chondral procedures, rehabilitation compliance, clinical outcome scores (International Knee Documentation Committee, Lysholm, Forgotten Joint Score, Global Perceived Effect), and clinical or radiological repair failure. Multivariable logistic regression with stepwise backward elimination was used to identify factors significantly associated with failure. Results One hundred fifty‐four patients were evaluated, with 35 (22.7%) classified as failures. The mean follow‐up was 48.8±18 months. Statistically significant predictors of failure included female sex ( P = .001); higher body mass index ( P = .001); higher grades of femoral ( P < .001) and tibial ( P = .018) chondral injury; use of a single tibial tunnel ( P = .043); noncompliance with rehabilitation ( P < .001); and lower International Knee Documentation Committee, Lysholm, Forgotten Joint Score, and Global Perceived Effect scores (all P < .001). Multivariable logistic regression identified female sex (adjusted odds ratios (OR) = 3.97, 95% confidence interval (CI) = 1.50–10.52, P = .006), higher body mass index (adjusted OR = 1.17 per unit increase, 95% CI = 1.04–1.32, P = .011), femoral chondral lesions of Outerbridge grade 1 (adjusted OR = 5.03, 95% CI = 1.12–22.56, P = .035) and grade 2 (adjusted OR = 13.05, 95% CI = 3.01–56.66, P = .001), and noncompliance with rehabilitation (adjusted OR = 3.40, 95% CI = 1.17–9.93, P = .025) as independent predictors of failure. Conclusions Medial meniscus posterior root repair using a transtibial tunnel technique had a 22.7% rate of clinical or radiological failure at a minimum follow‐up of 2 years. Female sex, higher body mass index, higher grades of femoral chondral injury, and noncompliance with rehabilitation were independently associated with failure. Only 8.5% of patients with a failed repair passed the 67.7 points threshold of the patient acceptable symptom state International Knee Documentation Committee compared with 63.0% of patients that did not have a repair failure. Level of Evidence Level IV, prognostic retrospective case series.