After induction of anesthesia, the patient is placed in the lateral decubitus position with the involved side up. The entire extremity and the ipsilateral iliac crest are prepared and included in the operative field. The femur is approached through a lateral incision (often through a previous incision that had been used for débridement), and the soft-tissue envelope is contoured to accept the tibia (Fig. 1). The acetabulum is reamed to bleeding cancellous bone with use of a hemispherical reamer. If possible, the diameter of the reamer is approximately the same as that of the calcaneal tuberosity.
An ovoid musculocutaneous flap, six to eight centimeters in width, is designed. The flap is centered over the muscles of the anterior compartment of the leg, extending from the level of the tibial plateau to the anterolateral aspect of the ankle joint. The incisions are carried down to the underlying tibia, fibula, and bones of the hindfoot, with care not to disturb the musculocutaneous perforating vessels coursing to the skin flap (Fig. 2).
The posterior tibial neurovascular bundle is isolated at the ankle distal to the musculocutaneous flap, and the forefoot is disarticulated through the calcaneocuboid and talonavicular joints. The bones of the amputated portion of the foot are removed and morselized, to be a source of bone graft. The tibiotalar and subtalar joints and the calcaneal branches of the posterior tibial artery are carefully preserved. The calcaneal tuberosity is denuded to cancellous bone.
The posterior tibial neurovascular bundle is dissected proximally to the popliteal space, with preservation of all nutrient branches to the tibia and the proximal part of the fibula. The remaining soft tissue superficial to the posterior tibial neurovascular structures is stripped from the tibia, with protection of the vascular structures and the musculocutaneous flap. The fibula, except for the distal six centimeters, is resected; however, the proximal one-third may be retained to broaden the osseous weight-bearing surface at the end of the amputation stump (Fig. 3).
Any remaining portion of the distal part of the femur as well as the proximal two to three centimeters of the tibia, including the articular surface and the subchondral bone, are resected. The peripheral margins of the tibial plateau are also resected, to a depth of one centimeter to diminish the flared shape of the proximal end of the tibia. The entire tibia and the musculocutaneous flap then are rotated 180 degrees in the sagittal plane and twisted in the transverse plane to place the calcaneal tuberosity in the reamed acetabulum. Care is taken during rotation to protect the vascular pedicle of the leg and to prevent acute angulation, torsion, or compression of the vessels. The popliteal vessels may need to be freed from the surrounding soft tissue for eight to ten centimeters proximal to the point of rotation so that the vessels pursue a gently curved course and are not tethered against the weight-bearing end of the proximal part of the tibia. With this 180-degree rotation of the osteomusculocutaneous unit, the length of the vessels is only slightly redundant and special measures, such as coiling, are not required to prevent kinking.
The neck of the calcaneus is positioned to place the axis of tibiotalar motion in the sagittal plane and the axis of subtalar motion in the coronal plane. Thus, the tibiotalar joint will provide flexion and extension and the subtalar joint, abduction and adduction. To control correct rotation, the axis of neutral rotation of the tibiotalar joint is marked by drawing a vertical line in methylene blue over the distal end of the tibia. This line is used as a guide to ensure correct positioning of the calcaneus within the acetabulum.
The calcaneus then is fixed to the pelvis with partially or fully threaded 6.5-millimeter cancellous-bone screws (Fig. 4). The placement of the screws in the acetabulum is similar to that in an acetabular component inserted without cement in total hip arthroplasty. Cancellous bone from the forefoot, patella, and fibula, and from reaming of the acetabulum, is packed around the site of the arthrodesis.
The abductor muscles, if present, are sutured to the fascia lata, and the soft-tissue envelope is closed over the tibia. Any remaining adductor muscles may be sutured through holes in the tibia to allow control of the stump. The wound is closed over deep drains, with the musculocutaneous flap incorporated into the wound in the lateral portion of the thigh to relieve tension at the time of closure (Fig. 5). A hip-spica cast that includes the stump is applied immediately.
Postoperatively, the patient wears the hip-spica cast and is non-weight-bearing for eight weeks. If union is evident at that time, wrapping and preparation of the stump are begun for prosthetic fitting. Weight-bearing may be initiated when the soft-tissue contour of the stump is suitable for fabrication of a socket for a preliminary prosthesis.
CASE 1. A thirty-eight-year-old woman, who weighed eighty-four kilograms and was 155 centimeters tall, was seen for evaluation of a non-union of an infected femoral shaft. Sixteen years previously, the patient had had fibrous non-union with two centimeters of shortening after treatment of a grade-I open fracture4 of the femoral shaft with serial irrigation, débridement, delayed closure, and application of a hip-spica cast. An attempt was made to obtain union by means of femoral lengthening with external fixation three years before she was seen by us. The diaphyseal corticotomy site failed to unite. Two attempts at open reduction and internal fixation also failed, and interlocking intramedullary nailing with reaming was done subsequently. Deep infection with Enterococcus developed six months postoperatively. The patient was managed twice with irrigation and débridement at the site of the non-union, with retention of the nail, and intravenous administration of ampicillin (two grams four times a day). The patient then was referred to us for evaluation.
At the initial evaluation at our institution, the patient was afebrile and the vital signs were stable. She had multiple scars and tender, firm edema about the lateral aspect of the thigh but no active drainage. The passive range of motion of the hip was full and symmetrical, but active motion was associated with pain in the thigh that prevented the patient from walking. The hemoglobin level was 102 grams per liter, the leukocyte count was 1 x 109 per liter, and the erythrocyte sedimentation rate was twenty-five millimeters per hour. Radiographs demonstrated a femoral non-union with the fixation device in place (Fig. 6-A).
Exploration of the site of the non-union revealed pus and necrotic bone. The intramedullary nail, which was loose, was removed. A fourteen-centimeter segment of necrotic bone containing purulent material was excised from the femoral diaphysis until viable bone was encountered. Vancomycin-resistant coagulase-negative Staphylococcus epidermidis was grown on culture. The patient then was managed with two serial procedures, two days apart, which consisted of irrigation of the wound, débridement, and exchange of a vancomycin-impregnated polymethylmethacrylate spacer. Once a granulating tissue bed had been obtained and there was no growth on culture, the wound was closed over a similar spacer, and ampicillin (two grams) was administered intravenously every six hours for six weeks. A repeat exploration was performed at six weeks. The wound had healed. There was no evidence of persistent infection on analysis of frozen sections or inspection of the wound at the time of the operation. Therefore, reconstruction was accomplished with an intercalary femoral shaft allograft, a vascularized graft from the ipsilateral fibula, and fixation with a modular plate and bone-grafting (Fig. 6-B).
Deep infection recurred one month later, and two serial débridements were done, with eventual removal of all of the allograft, the fibula, and the metallic components. Pseudomonas aeruginosa, Corynebacterium, and coagulase-negative Staphylococcus grew on culture. Two subsequent operative débridements with removal of all necrotic infected bone resulted in resection of the femur proximally to the subchondral layer of the femoral head and distally to the subchondral bone of the femoral condyles.
At this point, the patient was not considered to be a candidate for additional reconstruction with an allograft or a prosthesis because of refractory deep infection and the extent of the femoral bone loss. Two options, disarticulation at the level of the hip and tibia-hindfoot rotationplasty, were discussed carefully with the patient. She wanted to avoid disarticulation if possible; therefore, she was managed with resection of the remaining part of the femur and the tibial plateau, osteomusculocutaneous tibia-hindfoot rotationplasty, and calcaneopelvic arthrodesis (Fig. 6-C). The patella was excised, denuded of cartilage, and used as a corticocancellous autogenous bone graft.
During the first two months postoperatively, it was necessary to perform two débridements of small areas of aseptic, superficial wound necrosis, followed by use of an eight by five-centimeter split-thickness skin graft.
The stump was immobilized in a hip-spica cast until tomography demonstrated union at the site of the calcaneopelvic arthrodesis at eight weeks postoperatively. The stump had to be revised twice, for contouring and shortening, before it could be fitted with a standard above-the-knee prosthesis.
At the time of the latest follow-up, at forty-four months, the patient was bearing full weight with a suction-suspension socket prosthesis with a knee joint. She had a Trendelenburg gait and used a cane for long walks. The active and passive range of motion was 45 degrees of flexion, 0 degrees of extension, 35 degrees of abduction, and 20 degrees of adduction. She was very satisfied with the result.
CASE 2. A fifty-one-year-old man who had osteochondromatosis and insulin-dependent diabetes mellitus had been managed with resection of a grade-I chondrosarcoma of the proximal part of the femur and insertion of a proximal femoral replacement (a Bateman bipolar endoprosthesis) ten years before he was seen by us. Painful acetabular erosion led to a subsequent total hip arthroplasty. Because of chronic dislocation of the hip, an open relocation was performed with excision of impinging heterotopic bone and scar tissue.
The patient did well until six years later, when he was seen because of drainage from the wound (Fig. 7-A). Operative exploration revealed gross infection. Pseudomonas aeruginosa, Escherichia coli, Streptococcus viridans, and coagulase-negative Staphylococcus grew on culture of operative specimens. After an attempt to suppress the infection with antibiotics (500 milligrams of amoxicillin taken orally three times a day) was unsuccessful, a resection arthroplasty was performed with débridement of all components, all cement, and all infected tissue. Only a short segment of the distal part of the femur remained after a subsequent débridement (Fig. 7-B). The wound in the thigh was closed over a vancomycin-impregnated polymethylmethacrylate spacer within the femoral void.
Because of the severity of the previous infection and the small amount of remaining bone, the patient was not considered to be a candidate for a prosthetic replacement or an allograft. He chose to have a tibia-hindfoot osteomusculocutaneous rotationplasty rather than disarticulation at the level of the hip. This was performed eleven days after the wound-closure procedure.
The wounds healed uneventfully, and the stump was immobilized in a hip-spica cast for eight weeks. Wrapping of the stump then began, and the patient was fitted with an initial prosthesis for progressive weight-bearing at five months (Fig. 7-C).
At the time of the latest follow-up, at thirty-three months, the patient walked one-half mile (0.8 kilometer) a day with the support of a cane, had no problems with activities of daily living, and had returned to work at a job that had been modified so that it required only occasional standing. He had intermittent painful dysesthesia along the anterior aspect of the stump. A Trendelenburg gait was noted. The active and passive range of motion was 55 degrees of flexion, 30 degrees of extension, 40 degrees of abduction, and 20 degrees of adduction. The patient was very satisfied with the result.
Massive bone defects of the proximal part of the femur with destruction of the hip joint may be complicated by deep infection or alteration of the soft-tissue envelope of the thigh. Other host factors, such as diabetes, immune deficiency, or previous local irradiation, increase the risk of recurrent infection or complications related to the wound.
If the distal femoral bone stock, the local soft tissue, and the host conditions permit, femoral replacement with a prosthesis or an allograft can be considered. Moreover, rotationplasty, as described by Borggreve, by Van Nes, and by Kotz and Salzer, may be considered for highly selected patients in whom the distal femoral length is satisfactory, but it may be most applicable in children. However, if there is not enough distal femoral bone to seat a prosthesis or if severe previous infection is thought to contraindicate such reconstruction, there are few options. Such patients traditionally have been managed with disarticulation at the level of the hip, which is severely debilitating and disfiguring.
If the leg and the foot are viable, tibia-hindfoot osteomusculocutaneous rotationplasty with calcaneopelvic arthrodesis provides a vascularized source of bone and soft tissue to mimic a functional femoral shaft and hip joint. Patients are able to walk with a reconstruction that approximates an above-the-knee amputation with much less energy output than that needed for walking after disarticulation at the hip.