Medial vs. Lateral Meniscus Root Tears: Differences in Presentation, Treatment and Surgical Outcomes

Abstract

To compare medial (MMRT) versus lateral meniscus posterior horn root tear (LMRT) injury presentation, treatment, clinical outcomes following root repair, and risk factors for failure. One hundred and forty-one root tears in 137 patients were included. Radiographs were graded using Kellgren-Lawrence scores. MRI’s were reviewed for root tear classification and meniscus extrusion. Sub-analysis was performed on 62 patients who underwent root repair. Tegner, Lysholm, IKDC scores and progression to arthroplasty were analyzed in the repair groups. Patient demographics, radiographic findings, and clinical outcomes were compared between MMRT and LMRT. Of the 141 root tears, 109 were MMRTs, 30 were LMRTs, and two patients had both. At the time of injury, patients with MMRTs had a significantly higher age (MMRT=51.4 vs LMRT=24.6, p<.0001), BMI (MMRT=32.1 vs LMRT 25.8, P < .0001), KL score, (MMRT=1.3 vs LMRT=0.6, p<.0001), and higher rate of major meniscal extrusion (MMRT= 72% vs LMRT=20%, p<.0001). Of the 30 LMRT, 30/30 (100.0%) were treated with meniscal repair. With MMRT, 52/109 (48%) were treated non-operatively, 27/109 (25%) were treated with partial meniscectomy, and 30/109 (27%) were treated with meniscal repair. Sixty-two patients underwent meniscus root repair (30 medial, 30 lateral and 2 combined medial and lateral repairs) with an average 41 month follow-up. LMRT had significantly increased IKDC (LMRT=89.5, MMRT=80.4, p=0.02) and Tegner scores (LMRT=6.5, MMRT=5.1, p<0.05) compared to MMRT. LMRT repairs also had increased Lysholm scores, but the difference was not significant (LMRT=93.9, MMRT=89.6, p=0.20). Compared to MMRTs, LMRTs occur in younger male patients with lower BMI, less cartilage degeneration, less extrusion on MRI, and more commonly with a ligament injury. While good to excellent clinical outcomes were attained in select patients for both medial and lateral meniscus root repair, LMRTs had overall better results after repair, likely due to differences in injury characteristics.