Biomechanical analysis of the centralization procedure for extruded lateral menisci with posterior root deficiency in a porcine model

Purpose: The purpose of this study was to investigate the biomechanical properties of load distribution following a centralization procedure for extruded lateral menisci with posterior root deficiency in a porcine model. Methods: Six porcine knee joints were analyzed in a universal tester, as follows: 1) Intact; 2) Extrusion (meniscus extrusion was created by resetting the posterior root of the lateral meniscus, as well as the posterior synovial capsule); and 3) Centralization (two anchors were inserted at the lateral tibial plateau, and the meniscus was sutured to secure it close to the original position). Meniscus extrusion was evaluated using two markers put on the posterior cruciate ligament and the lateral meniscus, and the load distribution were assessed using a pressure mapping sensor system after applying a loading force of 200 N to the knee joint. Results: Distance between two markers (mm, Average; 95% CI) was larger in the extrusion group (21.9; 17.8, 25.6) than in the intact (18.1; 15.1, 22.7) or the centralization (15.3; 12.9, 18.0) groups. The contact area (mm(2)) in the middle of the meniscus was significantly smaller in the extrusion group (45.8; 18.5, 73.2) than in the intact (85.7; 72.1, 99.2) or the centralization (98.3; 88.8, 107.8) groups. The maximum contact pressure (MPa) in the tibial plateau was significantly higher in the extrusion group (0.37; 0.35, 0.40) than in the intact (0.29; 0.21, 0.37) or the centralization (0.29; 0.22, 0.36) groups. Conclusions: The centralization procedure enabled a reduction of the meniscus extrusion in the lateral meniscus with posterior root deficiency and restored the maximum load and contact pressure to values close to those of the normal knee joint. (C) 2019 The Authors. Published by Elsevier B.V. on behalf of The Japanese Orthopaedic Association.