[Skeletal lesions in chronic antero-medical instability of the knee (author's transl)].

The authors have operated on 110 cases of chronic antero-medial instability of the knee. In 33 cases there were femoral and tibial lesions. The medial tibial plateau was eroded at its posterior border with, at times, microfractures at this level or at the level of the posterior and axial part of the medial femoral condyle. This can be explained by abnormal movements of lateral rotation and translation of the posterior border of the medial tibial plateau which becomes subluxated under the femoral condyle. In 14 cases, periosteal elevation of the posterior capsule from the posterior border of the medial tibial plateau was found. The authors consider that this type of lesion may explain secondary degenerative lesions of the patella.