Vascularised and Modified Lower-Leg Rotationplasty for the Treatment of Severe Infection and Bone Loss of the Proximal Femur: A Case Report

Introduction

Extensive loss of bone from the femur is a challenging problem for the reconstructive surgeon. Especially in the case of severe and recurrent infections, which prohibit the utilisation of endoprostheses or allografts, limb salvage is often not feasible. While distal defects may leave sufficient stump length for an above-knee prosthesis or Borggreve's rotationplasty, defects involving the proximal third of the femoral bone often require hip disarticulation (1, 2). Besides severe disfigurement, hip amputation is associated with complete loss of lower extremity function and significantly diminishes the capacity to sit (3, 4).

To overcome this problem Sauerbruch introduced the lower leg rotationplasty in 1922 for reconstruction of extensive femoral defects (5). The tibia and fibula are flipped proximally to replace the femur and a pseudo joint between distal tibia and acetabulum formed a neo-hip articulation. Although this approach facilitated walking over short distances with means of crutches and prosthesis, the tibia dislocated soon after surgery. Furthermore, in case of infection related femoral bone loss, the least perfused distal tip of the rotationplasty covers the formerly infected wound bed and thus predisposes for impaired wound healing and infection recurrence. The latter can become crucial in the paraplegic patient, who is prone to pressure ulcers and thus relies on viable and well-perfused soft tissues in the hip region. Therefore, stabilisation of the neo hip joint and enhanced perfusion at the distal tip are desirable modifications of the lower leg rotationplasty.

In this case report we present a supercharged and modified lower-leg rotationplasty for treatment of severe femoral osteomyelitis in a paraplegic patient.

Case

A 38-year-old male suffered a complete spinal cord injury at T4 level after a bicycle accident. Since the accident the patient was dependent on a wheel chair and developed recurrent ulcers in the greater trochanter and inguinal region. 2 months before admission to our department, the patient was diagnosed with osteomyelitis of the proximal femur, which was related to 2 stage 4 groin ulcers. A surgical debridement aimed at a Girdlestone situation and secondary closure. However, wound healing was significantly impaired showing progressive wound dehiscence and infection. In addition, magnetic resonance imaging (MRI) revealed ongoing osteomyelitis affecting the proximal half of the remaining femoral bone.

At that point, the patient was transferred to our department for further debridement and reconstruction. Reconstructive considerations included allograft and endoprosthesis, which, however, were not deemed promising due to recurrent infections and limited shaft length after debridement. Consequently, the only 2 options left were lower leg rotationplasty and high amputation, i.e. disarticulation at the level of the hip. After presentation of the case in our interdisciplinary extremity board and careful discussion with the patient the decision was made for a lower leg rotationplasty and closure of both medial soft tissue defects with a transposition flap from the thigh. This decision was made in consideration of the paralysed lower extremities but the importance of stable seating position to operate a wheel chair. Furthermore, the vascular surgeon, who is part of our extremity board, suggested to supercharge the rotationplasty due to small stenosis of the superficial femoral artery.

To limit the surgical trauma we followed a 2-stage approach, in which we first resected all infected tissue including the entire femur and subsequently undertook the rotationplasty (Fig. 1).

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Fig. 1

Intraoperative picture of removal of the infected femoral bone.

The rotationplasty was performed in a lateral decubitus position and under general anaesthesia. Through a lateral incision the proximal tibia plateau, the fibula head and 6 cm of the distal fibula were resected. The foot was amputated at the level of the upper ankle joint but leaving the tendons of the foot flexors 5 cm longer than the amputation stump. Subsequently, the lateral 2/3 of the skin of the lower leg were epifascially dissected and the tibia and fibula with surrounding muscles and medial skin were laterally flipped upwards into the thigh defect (Fig. 2). For proximal fixation and stabilisation of the neo-hip joint, the foot flexor tendons were sutured into the acetabulum. Finally, we connected the posterior tibial artery to the inferior epigastric artery through an interpositional vein graft to supercharge the rotationplasty. With respect to the soft tissue defects in the groin, mobilisation of a transposition flap from the thigh could only close the lateral defect. The medial defect was temporarily covered by negative pressure wound therapy dressing. Pre- and postoperative x-rays are depicted in Figure 3.

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Fig. 2

Intraoperative picture of the rotationplasty. After dissection of the anterio-medial skin of the lower leg and amputation of the foot (upper left), the remaining tibia and fibula bones were flipped laterally upwards in to the thigh defect (upper right). Subsequently the posterior tibial artery was supercharged by the inferior epigastric artery through a venous interposition graft (lower left). After fixation of the extensor tendons of the foot at the acetabulum, tension-free skin closure was feasible (lower right).

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Fig. 3

Pre- (left) and postoperative (right) x-rays of the right thigh. Preoperative x-ray shows proximal femur osteomyelitis after resection of the femoral head. Postoperative x-ray demonstrates the upwards-flipped lower leg, of which the distal tibia does now articulate with the acetabulum and thus forms a neo-hip joint.

The early postoperative course was uneventful and the patient was able to sit in his wheel chair with assistance at 2 weeks after surgery. During the next 2 months, however, 2 surgeries for seroma and haematoma drainage were necessary. In addition, closure of the medial groin defect was performed using a pedicled rectus abdominis flap from the contralateral side.

12 months after surgery, the patient was able to lift himself and both paralysed lower extremities into his wheel chair. The reconstructed thigh allowed for unhindered sitting for several hours. Passive range of motion was 90° of flexion, 0° of extension, 45° of abduction, and 20° of adduction. The patient was very satisfied with the result.

Discussion

In this case report we present a modification of Sauerbruch's rotationplasty. The new pseudo joint of the distal tibia and acetabulum was stabilised with means of the foot flexor tendons and flap perfusion was enhanced by supercharging the posterior tibial artery. Thereby, the patient was able to remain in seating position without customised seating adjustments, which would have certainly been necessary after hip disarticulation. Although not shown in this case report, further modification in the meaning of extending the skin paddle by the dorsum of the foot and flipping the lower leg upwards medially or dorsally could facilitate simultaneous coverage of trochanteric or sacral ulcers. However, the presented technique did not harm perforators of anterior lateral or medial thigh flaps, hamstring muscles or even tensor fascia lata flap, which can still be utilised for coverage of recurrent ulcers.

In 1997, Peterson et al (6) modified Sauerbruch's technique in 2 patients. The authors amputated the foot more distally at the height of the Chopard joint. Thereby, the preserved ankle joint replaced the hip joint after calcaneopelvic osteosynthesis. Although the latter approach improved stability of the neo-hip joint and allowed for full weight-bearing with transfemoral prosthesis, passive range of motion was limited to 45°-55° of hip flexion.

The patient presented in this case report has been completely paraplegic and dependent on a wheel chair. Consequently, the primary purpose of reconstruction was to facilitate a stable and up-right seating position. Therefore, sole attachment of the foot flexor tendons at the acetabulum was deemed sufficient, as axial weight bearing was not anticipated and increased mobility would facilitate full hip flexion for an up-right seating position.

Furthermore, the alternative calcaneopelvic osteosynthesis requires at least 8 weeks of immobilisation for osseo-integration, meaning bed rest for the paraplegic patient, and provides an additional risk for infection related to osteosynthesis material.

Supercharging is an established technique to enhance perfusion of pedicled or free flaps (7). Basically, supercharging means that an additional vessel is connected to supply the transferred tissue with blood. Especially in case of osteomyelitis, supercharged flaps provided reliable reconstruction of soft tissue defects, most likely due to increased blood supply (8, 9). While debridement and antibiotic therapy is mandatory for treatment of osteomyelitis, well-perfused tissue can support the healing process by delivering nutrients and antibiotics to the infection site. In the presented case we decided for supercharging because of an occlusion of the superficial femoral artery. This stenosis, however, was clinically negligible since perfusion of the lower leg and foot was sufficient. The interdisciplinary decision of our institutional extremity board for arterial supercharging was guided by the concern, that collateral circulation could be interrupted by the rotationplasty. The successful postoperative course of our patient underlines the efficacy of this primary interdisciplinary approach of extremity boards including at least plastic, trauma, and vascular surgery.