Side-to-side repair improves coronal meniscal extrusion in lateral meniscus oblique radial tears concomitant with anterior cruciate ligament reconstruction.

PURPOSE: To determine the proportion of lateral meniscus oblique radial tear repairs during anterior cruciate ligament reconstruction and compare extrusion and clinical outcomes between side-to-side repair of lateral meniscus oblique radial tear and posterior longitudinal tear repair.

METHODS

Among 609 primary anterior cruciate ligament reconstructions from 2016 to 2023, 34 patients with intraoperatively confirmed lateral meniscus oblique radial tear underwent side-to-side repair and magnetic resonance imaging at 6 months and 1 year; 27 with posterior longitudinal tears underwent all-inside repair. Coronal and sagittal lateral meniscal extrusion, clinical outcomes, knee stability and Knee Injury and Osteoarthritis Outcome Score subscales were compared. Multivariate regression assessed predictors of preoperative-to-1-year coronal extrusion change; receiver operating characteristic analysis assessed whether preoperative lateral meniscal extrusion distinguished tear types.

RESULTS

Lateral meniscus oblique radial tear treated with side-to-side repair accounted for 7.4% of cases. Preoperative coronal lateral meniscal extrusion was greater in the lateral meniscus oblique radial tear group than in the longitudinal tear group (1.71 ± 1.31 vs. 0.32 ± 0.61 mm; p < 0.001). Coronal extrusion improved by approximately 0.6 mm after lateral meniscus oblique radial tear repair and was similar between groups at 1 year; sagittal extrusion increased slightly in both groups. Clinical outcomes were similar at 1 year and final follow-up. Preoperative coronal lateral meniscal extrusion was an independent predictor of coronal extrusion change (β = -0.514, p < 0.001). Preoperative coronal lateral meniscal extrusion >1.0 mm identified lateral meniscus oblique radial tear with acceptable diagnostic performance (area under the curve = 0.787, p < 0.001).

CONCLUSIONS

Side-to-side lateral meniscus oblique radial tear repair during anterior cruciate ligament reconstruction reduced coronal extrusion by 1 year to levels comparable to those of longitudinal tear repair, with similar clinical outcomes. These findings support side-to-side repair as a reliable meniscal preservation strategy.

LEVEL OF EVIDENCE: Level III.