Female Sex, Higher Outerbridge Grade, and Preoperative Tibial Edema Are Associated With Failure After Arthroscopic Posterior Medial Meniscus Root Repair.

PURPOSE: To characterize the prevalence of arthroscopic surgical revisions, postsurgical conversion to arthroplasty, and patient-reported outcomes of medical meniscus posterior root tear repairs at 1- and 2-year follow-up timepoints, with a focus on identifying predictors of treatment failure. METHODS: A retrospective case series study of patients who underwent primary arthroscopic medical meniscus posterior root tear repair performed at a tertiary referral center between 2017 and 2023, with a minimum of 1-year follow-up. Demographics, radiographic findings, intraoperative variables, and surgical outcomes were analyzed, and patients were contacted to further assess outcomes. Failure was defined as meniscal retear and/or conversion to knee arthroplasty, as confirmed by clinical examination and radiographic imaging by an orthopaedic surgeon. Univariate analyses used χ2 or Fisher's exact tests for categorical variables and t-tests for continuous variables. RESULTS: Fifty-three patients were included (mean age 54 ± 12 years, mean body mass index 33 ± 8 kg/m2, 69.8% women). Twelve patients (22.6%) met criteria for failure with a minimum of 1-year follow-up. Failure was associated with female sex (92% vs 63%, P = .033), preoperative tibial bone edema (58% vs 12%, P = .001), and higher medial compartment Outerbridge grade (2.8 ± 0.9 vs 1.9 ± 1.1, respectively, P = 0.015). Age, body mass index, fixation method, and preoperative extrusion were not associated with failure. Patients with successful outcomes showed significant improvement in pain and function, with mean visual analog scale score decreasing from 4.9 ± 3.1 to 2.1 ± 2.2 and Single Assessment Numeric Evaluation increasing from preoperative 51.7 ± 28.1 to 80.8 ± 18.2 at 2-year follow-up (P < .001 for both). CONCLUSIONS: In this small cohort, predictors of failure included female sex, preoperative tibial bone marrow edema, and higher Outerbridge classification, whereas age, body mass index, and preoperative extrusion were not associated with failure. Overall, arthroscopic medical meniscus posterior root tear repair provided meaningful symptomatic and functional improvements in most patients at 2-year follow-up. LEVEL OF EVIDENCE: Level IV, retrospective case series.