Biomechanical analysis of a centralization procedure for extruded lateral meniscus after meniscectomy in porcine knee joints.

The recently developed arthroscopic centralization for lateral meniscal extrusion has obtained satisfactory short-term clinical and radiological results and improves the meniscus biomechanical properties. However, the effectiveness of treatment for meniscus extrusion after partial meniscectomy still requires elucidation. This study investigated the effect of centralization with modifications from a mechanical viewpoint. Porcine knee joints (N = 6) were set in a universal tester under the following conditions: (1) Intact; (2) Meniscectomy: Inner half of the posterior half meniscus was removed; (3) Extrusion: Posterior meniscus was dislocated laterally by transecting the posterior root and the meniscotibial ligament; (4) Centralization-1: Centralization procedure using one anchor; (5) Centralization-2: Centralization procedure using two anchors; and (6) Centralization-ad: Centralization with capsular advancement using two anchors. Load distributions and contact pressure in the meniscus and tibial cartilage were evaluated with an axial compressive force of 200 N. After meniscectomy, the tibial cartilage load increased and that of the medial margin of the posterior part of the meniscus decreased. When the meniscus was extruded, the load was concentrated only on the tibial cartilage. Centralization-1 increased the load on the meniscus, while Centralization-2 further increased the meniscus load but decreased the tibial cartilage load. Centralization-ad further decreased the load on the tibial plateau. The average contact pressure of the tibial cartilage was significantly higher in the Extrusion group than in the Intact group or the Centralization-ad group. From a biomechanical viewpoint, centralization with capsular advancement was the most effective of the tested procedures for treatment for an extruded meniscus after partial meniscectomy.