Knee osteoarthritis : is it just wear and tear ? Articular cartilage is thickened in preserved areas of osteoarthritic knees

Our hypothesis was that preserved cartilage in osteoarthritic (OA) joints is thicker compared to non-OA joints. We took the femorotibial joint as a model. First, we determined that Computed Tomography arthrography (CTA) is the imaging modality with the highest sensitivity and interobserver agreement for the detection of cartilage surface lesions. Second, we analyzed sources of interobserver disagreement for the grading of cartilage at CTA. Third, we identified a target area of cartilage that is frequently preserved in knee OA until late stages of the disease, at the posterior aspect of the medial condyle. Finally, we showed that cartilage thickness at the posterior aspect of the medial condyle is increased in OA knees compared to non-OA knees, and that this thickening is correlated to the grade of OA.