Radiographic findings in osteoarthritis of the knee joint are hot correlated with cartilage histomorphology or immunohistochemistry

The purpose of this study was to investigate whether radiographic joint spa ce narrowing (JSN) of the lateral knee compartment predicts the histomorpho logical or immunhistochemical grading in cases of osteoarthritis of the kne e joint. The lateral joint space was measured on weight-bearing radiographs. Femoral osteochondral plugs of 29 patients undergoing total knee replacement were obtained from lateral condyles. All these patients had severe osteoarthriti s of the medial compartment, with the lateral compartment showing different stages of osteoarthritis. The specimens were histomorphologically evaluate d with the Mankin score, and the expression of the cartilage-degrading enzy mes MMP1 and MMP3 was measured. There was no correlation between the joint space and histomorphological or immunohistochemical data, whereas the enzyme expression was correlated with histomorphological grading. We conclude that radiographic assessment alone is not sufficient to evaluate the cartilage damage of the lateral condyle.