Degenerative medial meniscus posterior root tear and non-root tear do not show differences in joint survival and clinical outcome after partial meniscectomy.

PURPOSE: No comparative studies of outcomes between degenerative medial meniscus posterior root tear (MM PRT) and non-root tear (NRT) have been conducted. This study aimed to compare joint survival and clinical outcome between MM PRT and MM NRT after partial meniscectomy with proper control of confounding factors. METHODS: One hundred and ten patients each in MM PRT and MM NRT groups who underwent arthroscopic partial meniscectomy were retrospectively evaluated through propensity score matching. Joint survival was assessed on the basis of surgical and radiographic failures. Clinical outcomes were assessed using the Lysholm score. RESULTS: The confounding variables were well balanced between the groups, with standardized mean differences of < 0.2 after propensity score matching. Failures occurred in 30 (27.3%) and 35 patients (31.8%) in the MM PRT group and MM NRT group, respectively. The estimated mean survival times were 12.5 years (95% confidence interval [CI] 11.5-13.5) and 11.7 years (10.7-12.7), respectively. There were no significant differences in the overall survival rate and Lysholm score between the two groups (n.s.). CONCLUSION: In middle-aged patients with degenerative MM PRT, joint survival and clinical outcome showed comparable results with those with MM NRT after partial meniscectomy. Arthroscopic partial meniscectomy is one of the effective treatments for MM PRT with consideration of various patient factors. LEVEL OF EVIDENCE: III.