Posterior Root Tears of the Lateral Meniscus Only Affect Tibiofemoral Contact Forces when the Meniscofemoral Ligament Is Involved: A Cadaveric Study

The objective of this study was to examine the impact of progressive radial tears in the lateral meniscal root on the lateral compartment contact forces and joint surface area through a range of motion of knee and evaluate the role of the meniscofemoral ligament (MFL) in preventing adverse tibiofemoral joint forces. Ten fresh frozen cadaveric knees were tested using 6 experimental conditions (0% lateral meniscal posterior root tear, 25% tear, 50% tear, 75% tear, 100% tear, 100% tear and resection of MFL) at five flexion angles (0°, 30°, 45°, 60°, and 90°) under 100-1,000-N axial load. Contact joint pressure and lateral compartment surface area were measured using Tekscan sensors. Statistical analysis, including descriptive, ANOVA, and post hoc Tukey analysis, was performed. Progressive radial tears of the lateral meniscal root were not associated with an increase in tibiofemoral contact pressure or decrease in lateral compartment surface area. Complete lateral root tear and resection of MFL were associated with increased joint contact pressure (P < .001) at knee flexion angles of 30, 45, 60, and 90° and decreased lateral compartment surface (P < .001) at all knee flexion angles area compared to complete lateral meniscectomy alone. Isolated complete tears of lateral meniscus root and progressive radial tears of the lateral meniscus posterior root were not associated with any change to tibiofemoral contact forces. However, additional resection of the MFL increased contact pressure and decreased lateral compartment surface area.