Pressure distribution at the ankle joint.

Biomechanical factors such as trauma or overweight are discussed in relation to the aetiology of osteochondral lesions. As a consequence of the possible influence of these factors on joint loading patterns the pressure distribution on the load-bearing ankle joint has been investigated in a cadaveric biostatic model. By creating different joint positions with and without either lateral or medial ligament dissection, mimicking a ligamentous supination or pronation trauma, the pressure distribution under these various loading conditions was determined using pressure-sensitive film. The location of transduced contact area, the size and the amount of pressure was evaluated during the study. The results show that the location of the contact area was dependent on the joint position. Even without ligament dissection there was a minimum of contact area in the varus and the supination position with a pressure maximum lying on the medial border of the talus. Ligament dissection of the lateral ligaments resulted in an increased contact area in all the joint positions except for the varus and the supination position. In addition, the pressure increased significantly in the dorsal extension, varus and supination positions following lateral ligament dissection. Medial ligament dissection yielded results opposite to those observed with the lateral ligament dissection. The pressure maximum was observed to be, in the valgus and pronation position, on the lateral talar border with a significant increase of the pressure maxima following ligament dissection.