Medial Meniscus Root Repair Is Associated With Superior Outcomes As Compared With Partial Medial Meniscectomy at Minimum 5 Years: A Systematic Review and Meta-analysis

Background: Posterior medial meniscus root tears (PMMRTs) are frequently observed injuries that alter tibiofemoral biomechanics, yet the long-term outcomes are poorly described. Purpose: To perform a systematic review and meta-analysis of the current literature on long-term clinical and radiographic outcomes of operatively managed PMMRTs. Study Design: Meta-analysis and systematic review; Level of evidence, 4. Methods: A systematic review was performed with the inclusion criteria of English-language studies, diagnosis of PMMRT on magnetic resonance imaging, and minimum 5-year radiographic or patient-reported outcome (PRO) metrics. Data analysis included management strategy, surgical technique, meniscal extrusion, medial joint space, PROs, and radiographic measurements. Failure was defined as conversion to arthroplasty, subsequent partial medial meniscectomy (PMM) and/or proximal tibial osteotomy, or clinical failure on PROs. Continuous outcome variables were analyzed with a random effects meta-analysis of mean differences. Chi-square meta-analysis was also used to analyze categorical variables. Results: Twelve studies were identified with >5-year follow-up after PMMRT (mean ± SD, 84.1 ± 11.0 months). Five studies performed PMM, 6 performed medial meniscus root repair (MMR), and 1 utilized either meniscectomy or repair. There were 797 total patients (female, n = 667; 83.7%), with mean ages ranging from 47.2 to 65. Both interventions showed significant PRO improvements after surgery: PMM (pre- vs postoperative Lysholm, 56.1 vs 68.2; P < .01) and MMR (Lysholm, 52.1 vs 83.1; International Knee Documentation Committee [IKDC], 40.0 vs 72.8; P < .01). MMR had significantly lower Kellgren-Lawrence grades (PMM vs MMR, 2.4 vs 1.8; P < .01) and superior IKDC scores (46.5 vs 72.8; P < .01) as compared with PMM. Additionally, PMM had a significantly higher failure rate (23% vs 5.3%) and conversion to knee arthroplasty (20.5% vs 3.5%) as compared with MMR, with odds ratios of 9.8 and 10.2, respectively. Conclusion: This systematic review and meta-analysis of studies with >5-year minimum follow-up found that PMM was associated with a 10-fold increase in clinical failure and conversion to knee arthroplasty relative to MMR in observational studies. In addition, MMR demonstrated superior Kellgren-Lawrence grades and IKDC scores as compared with PMM. The findings of the current analysis suggest that MMR is associated with superior outcomes as compared with PMM at mid- to long-term follow-up.