This section is from the book "Applied Anatomy: The Construction Of The Human Body", by Gwilym G. Davis. Also available from Amazon: Applied anatomy: The construction of the human body.
Disarticulation at the knee-joint is usually done either with a long anterior and short posterior or two lateral flaps. This amputation differs from others in the fact that a large rounded mass of bone - the condyles - with no muscles is to be covered by the flap. Therefore the flaps must be ample and if they are not a piece of the femur must be resected. The internal condyle is larger and projects more than the external. The cicatrix is drawn posteriorly by the hamstring muscles and the resultant stump is good for pressure bearing.
Fig. 556. - Bow-legs.
If possible the semilunar cartilages should be left on the femur, the incision for disarticulation being made between them and the tibia. The object of so doing is to prevent the retraction of the soft parts and the resultant protrusion of the bone. The extremities of the incision should be well back, so that the lateral ligaments can be readily divided, and should not extend higher than the edge of the tibia. If infection follows, pus may collect in the suprapatellar (subfemoral) bursa.
Fig. 557. - The popliteal space.