Effects of Serial Sectioning and Repair of Radial Tears in the Lateral Meniscus

Background: Radial transection of the peripheral fibers of the meniscus could render it nonfunctional; however, the biomechanical consequences of a complete lateral meniscal radial tear and repair in human specimens have not been elucidated. Hypothesis: A complete radial tear will exhibit knee contact mechanics approaching those of total meniscectomy. Repair of complete radial tears will re-create normal load transmission across the joint. Study Design: Controlled laboratory study. Methods: Five matched pairs of fresh-frozen human cadaveric knees were tested in axial compression (800 N) at 2 knee flexion angles (0° and 60°). Six meniscal conditions were sequentially tested: (1) intact lateral meniscus; radial width tears of (2) 50%, (3) 75%, and (4) 100%; (5) meniscal repair; and (6) total meniscectomy. Repairs were pair matched and used either an inside-out or all-inside technique. Tekscan sensors measured tibiofemoral contact pressure, peak contact force, and contact area in the lateral meniscus and medial meniscus. Results: Complete radial tears of the lateral meniscus produced significant increases in mean contact pressure (P = .0001) and decreased contact area (P < .0001) compared with the intact state. This effect was significantly less than that of total meniscectomy (P < .0023). Lesser degrees of radial tears were not significantly different from the intact state (P > .3619). Mean contact pressure after either repair technique was not significantly different from the intact state (P = .2595) or from each other (P = .4000). Meniscal repair produced an increase in contact area compared with a complete tear but was still significantly less than that of the intact meniscus (P < .0001). The medial compartment showed no significant difference between all testing conditions for 0° and 60° of flexion (P ≥ .0650). Conclusion: A complete radial meniscal tear of the lateral meniscus has a detrimental effect on load transmission. Repair improved contact area and pressure. Contact pressures for repaired menisci were not significantly different from the intact state, but contact area was significantly different. Biomechanical performance of repair constructs was equivalent. Clinical Relevance: Repair of complete radial tears improves joint mechanics, potentially decreasing the likelihood of cartilage degeneration.