Biomechanical factors in wound healing following knee arthroplasty

A significant proportion of deep infections following knee arthroplasty are consequent on a failure of primary wound healing. The management of such infections is difficult and the functional outcome is poor. It is essential to ensure that the initial biomechanical conditions are such that wound healing is encouraged. The ability of a wound to heal is dependent on factors such as the orientation of the skin incision, the wound tension and the viability of the wound edges as assessed by skin oxygen tension estimations. Consideration of these factors has led us to advocate the use of the medial parapatellar incision for knee arthroplasty. Early, excessive knee flexion following arthroplasty can lead to significant wound edge hypoxia but by modifying the rehabilitation programme and with the administration of 24% oxygen to the patient in the perioperative period, this effect can be minimized. Modification of the surgical techniques involved in knee arthroplasty can help preserve the vascular supply and hence the viability of the wound edge, and thus achieve a suitable biomechanical environment for primary wound healing.