Different patterns of cartilage wear in medial and lateral gonarthrosis.

We studied the morphologic changes of cartilage wear on the resected parts of the joint in 42 knees operated on with a total knee prosthesis. The medial and lateral compartments were divided into 6 equal regions on both the tibial and femoral sides. The amount of cartilage/bone destruction was classified into 4 grades in each region. In medial and lateral arthrosis, maximal wear was found in the middle of the joint, but it was more marked in the lateral group. In the medial group, wear was greater in the anterior regions. In the lateral group, we found more wear in the posterior regions. We ascribed these findings to different anterior/posterior translations of the medial and lateral condyles during flexion/extension of the knee joint.