A meta-analysis of clinical and radiographic outcomes of posterior horn medial meniscus root repairs

PURPOSE: Although interest in medial meniscus posterior root tear (MMPRT) repair has increased, few case series have been reported. This meta-analysis aimed to examine the clinical and radiological effects of MMPRT repair by pooling pre- and post-operative data from case-series reports. METHODS: A literature search was performed using MEDLINE/PubMed, the Cochrane Central Register of Controlled Trials, and EMBASE databases. Pre- and post-operative data were pooled to investigate the effects of MMPRT repair, including the Lysholm score improvement, meniscal extrusion (mm) reduction, progression of the Kellgren-Lawrence (K-L) grade, and cartilage status according to the Outerbridge classification. Treatment effects included paired standardized mean differences (difference in the pre- and post-operative mean outcomes divided by the standard deviation) for the Lysholm score and meniscal extrusion, as well as the pooled event rates of progression of K-L grade and cartilage status. RESULTS: As treatment effects, the Lysholm score increased by as much as 3.675 (P < 0.001), whereas meniscus extrusion was not reduced (n.s.). The overall pooled event rates of progression of K-L grade and cartilage status were 10.6 and 17.3 % (P < 0.001), respectively. CONCLUSIONS: According to the current literature, MMPRT repair resulted in significant improvements in the post-operative clinical subjective scores compared with the preoperative status. However, meniscus extrusion was not reduced. Considering the occurrence of progression of K-L grade and cartilage status, it did not prevent the progression of arthrosis completely. Based on these results, repair results in favourable outcomes for MMPRT. LEVEL OF EVIDENCE: Meta-analysis, Level IV.