Resection, rotationplasty, and femoropelvic arthrodesis in severe congenital femoral deficiency. A report of the surgical technique and three cases.

BACKGROUND: The major problems associated with severe congenital deficiency of the femur are an unstable hip joint and a femur that is more than 50% shorter than the contralateral, normal femur. The usual treatment of these extreme cases of congenital femoral deficiency is a Syme or Boyd amputation when the child begins to walk. A knee fusion is done when the child is older, and the patient functions as an above-the-knee amputee. Rotationplasty has been described as an alternative treatment that allows the patient to function as a below-the-knee amputee. None of the currently described types of rotationplasty address the problem of the unstable hip.

METHODS: Three patients with severe congenital femoral deficiency underwent a unique single-stage reconstruction. In this procedure, the limb is completely detached except for the sciatic nerve and the femoral vessels. The proximal part of the dysplastic femur and some muscles are resected. The residual limb is externally rotated 180 degrees and the rotated distal part of the femur is fused to the pelvis. All of the muscles distal to the knee remain undisturbed.

RESULTS: The anatomical knee in its rotated position functioned as a hip with flexion and extension, and the femoropelvic arthrodesis provided a more stable support. The rotated ankle acted as a knee, and the patients functioned as below-the-knee amputees. The duration of follow-up of these three patients was eight, six, and four years. Active hip flexion was 10 degrees to 70 degrees , 10 degrees to 90 degrees , and 0 degrees to 80 degrees , and active knee flexion was 900 and 95 . The patients' gait continued to improve as they matured.

CONCLUSIONS: The femoropelvic arthrodesis provides a stable hip. Since the muscles distal to the knee are not disturbed, the problem of derotation of the limb, which is often seen following the Van Nes rotationplasty, is not seen after this operation.