56.7 Disarticulating the knee

Disarticulating the knee: (1) Is one of the easier amputations. (2) Preserves the distal femoral epiphysis of a child, and so allows his stump to grow. (3) Cuts little muscle and no bone, so it is quick, there is little bleeding, and infection is unlikely. (4) Allows the normal weight bearing end of the bone to bear weight in the prosthesis. Although long flaps are necessary to bring the scar posteriorly, there are such excellent anastomoses round the knee that they seldom become gangrenous, so it is a good amputation for ischaemic patients. If you have a choice, disarticulating the knee is better than amputating above it. Good prostheses are now available for disarticulated knees.

Figure 56.12: DISARTICULATING THE KNEE. A, the flaps marked out. B, the flaps being raised. C, cutting the cruciate ligaments and the posterior joint capsule. D, cutting the tibial nerve. E, the patellar tendon sewn to the anterior cruciate ligaments. F, the stump with drains in place. After Champbell, with kind permission.