Minimal-resection arthroplasty to treat meniscal tears with associated condyle lesions: finite element analysis

An early intervention prosthesis which minimizes the extent of resected healthy bone would be advantageous to patients for whom a total or unicompartmental replacement would sacrifice extensive healthy tissue. In this study the use of a device to treat osteoarthritis localized upon a single condyle of the femur with an associated irreparable meniscal tear is considered. The effects of implant alignment are considered from the standpoint of kinematics and potential for cartilage damage. The results suggest that alterations in implant position influence joint kinematics during stance. Anteroposterior (AP) adjustment of the medial prosthesis minimizes the capability of the knee to rotate internally, placing higher demands on the cruciate ligaments. AP adjustments of the lateral prosthesis induces greater posterior drawback, reducing internal-external rotation. Natural knee kinematics are best reproduced by the medial condyle rather than the lateral condyle. Stress exposure of the cartilage increased with the introduction of the femoral condyle prosthesis, which may progress eventually to osteoarthritis, although the results indicate that the medial condyle device is less likely to lead to cartilage damage than is lateral condyle replacement. This study demonstrates that a minimal-resection femoral condyle device may provide sufficient knee joint function to serve as an interim treatment prior to total or unicompartmental knee arthroplasty.