PRESSURE DISTRIBUTION AT THE KNEE-JOINT - INFLUENCE OF VARUS AND VALGUS DEVIATION WITHOUT AND WITH LIGAMENT DISSECTION

Traumata or repetitive microtraumata, malalignment with varus or valgu s deviation, or chronic joint instability are discussed in the aetiolo gy of osteoarthritis and osteochondritis dissecans of the knee. Biomec hanical factors influencing the patterns of pressure distribution at t he articular surface and the subchondral bone are suggested to be most important in the pathogenesis. Consequently, the patterns of pressure distribution at the femoral condyles of weight-bearing knee joints we re investigated in a cadaveric biostatic model. The pressure in the ar ticular joint space was evaluated with pressure-sensitive films of the knee in different joint positions in the coronal plane (10 degrees va rus, 10 degrees valgus, and neutral position) without and with medial collateral ligament (MCL), lateral CL (LCL), MCL + anterior cruciate l igament (ACL) or LCL + ACL ligament division. Results demonstrated tha t the location of the contact area and the peak pressure depended on t he joint position and stage of ligamentous division. Without ligament division, a maximum peak pressure was observed at the medial condyle i n the neutral and varus positions. Only in the valgus position did the lateral condyle show a higher peak of pressure than the medial condyl e. Ligament division of the LCL and LCL + ACL resulted in an increase of peak pressure at the medial condyle, particularly in the varus posi tion. Division of the MCL and MCL + ACL ligament complex reduced the d ifferences between the medial and lateral condyle. In the valgus posit ion, the peak pressure was significantly higher at the lateral condyle . The absolute maximum peak pressure was measured in the varus positio n at the medial condyle after division of the LCL and ACL. The absolut e minimum was found in the valgus position at the medial condyle after division of the MCL and ACL. No significant change of the location of the centre of peak pressure area was observed due to the different jo int positions.