ORIF of an intertrochanteric fracture proximal to an above-knee amputation using two AO femoral distractors

Abstract

We present the case of a patient who sustained a displaced intertrochanteric fracture proximal to an above-the-knee amputation. Reduction was obtained using 2 AO femoral distractors placed anteriorly and laterally, spanning the hip joint. Fracture fixation was achieved using a sliding hip screw and side plate. Intertrochanteric fractures proximal to an above-the-knee amputation are challenging to manage because of the difficulty in obtaining sufficient skin traction on the stump to effect reduction. Using two femoral distractors anteriorly and laterally can help obtain length and alignment in these difficult cases.

Introduction

Hip fractures (femoral neck and intertrochanteric) proximal to an above-the-knee amputation present several challenges with surgical treatment. The inability to place the foot in traction and utilize a standard fracture table makes reduction difficult. Femoral neck fractures requiring arthroplasty are complicated by the inability to use of the knee and the leg for reduction and dislocation. There is a little in the literature describing techniques to treat displaced intertrochanteric hip fractures in patients with an above-the-knee amputation (AKA). We successfully treated such a fracture using 2 femoral distractors and describe that case here.

Case summary

A 49-year-old man, with a history of left AKA performed 15 years earlier for ischemia secondary to diabetes, presented to our emergency department with a displaced left intertrochanteric hip fracture. He fell while walking to the bathroom using crutches sustaining this injury. He now had substantial pain with any motion of the left thigh stump. Prior to the fall, the patient had been ambulating with 2 crutches and was not using an AKA prosthesis. His past medical history is significant for insulin-dependent diabetes, peripheral vascular disease, and femoral popliteal bypass 18 years earlier. Radiographs of the left hip demonstrated a displaced left intertrochanteric hip fracture (Fig. 1A).

Fig. 1.

A. Anteroposterior radiographs of the left hip and left femoral stump demonstrating the displaced intertrochanteric hip fracture and amputated distal femur. B. Clinical photo showing intraoperative positioning of the patient and limb on a radiolucent flat table.

The patient was indicated for surgical stabilization of the left intertrochanteric hip fracture in order to reduce pain, restore function and minimize the pulmonary and decubitus ulcer complications associated with prolonged recumbency if the patient is treated nonsurgically. The patient was positioned on a radiolucent table (Fig. 1B). The C-arm fluoroscopic unit was brought in from the opposite side. Intravenous antibiotics were administered. After prepping and draping the femoral stump and ipsilateral pelvis, two AO femoral distractors (Depuy Synthes, Warsaw, IN, USA) were used to achieve reduction. One femoral distractor was placed anteriorly, with a 6.0 mm Schanz pin in the anterior inferior iliac spine (AIIS) extending to the sciatic notch, and a second 6.0 mm Schanz pin anteriorly in the distal quarter of the femoral stump. The second set of Schanz pins were placed in the lateral ilium 2 cm proximal to the acetabulum and in the distal lateral aspect of the femoral stump (Fig. 2A, B). Standard anteroposterior and lateral views were used for all pins except the AIIS pin which required obturator outlet, obturator inlet and iliac oblique views to visualize the LC2 corridor. The distal pins were placed externally rotated relative to the respective proximal pins to effect internal rotation with fixator application.

Fig. 2.

Positioning of Schanz pins in the pelvis (A) and distal femoral stump (B).

On fluoroscopic imaging, the distractors were lengthened until length and alignment were achieved. This dual fixator construct allows for control of length and alignment (Fig. 3). Rotation must be obtained before Schanz pin placement.

Fig. 3.

Clinical photos showing intraoperative placement of both femoral distractors.

The fracture was stabilized with a standard sliding hip screw and side plate (Dynamic Hip Screw, Depuy Synthes, Warsaw, IN, USA) placed through the lateral approach to the femur with elevation of the vastus lateralis. The AO compression screw (Depuy Synthes) was used pull the hip screw laterally to obtain maximum compression at the fracture site, as the patient does not weight bear through a prosthesis. Postoperatively, the patient was encouraged to mobilize with crutches under the supervision of a physical therapist. He was placed on DVT prophylaxis (low molecular weight heparin) for 4 weeks and postoperative antibiotics for 24 h. The patient had an uneventful postoperative course. At 8 weeks, the patient was ambulating comfortably with crutches and radiographs demonstrated healing of the left intertrochanteric fracture. At 1 year postop, the patient was ambulating with crutches and without pain. Radiographs at this time demonstrated a healed intertrochanteric fracture (Fig. 4A, B).

Fig. 4.

Anteroposterior (A) and lateral (B) radiographs of the left hip 1 year after surgery demonstrating a healed left intertrochanteric fracture.

Discussion

Surgical stabilization of hip fractures in patients with ipsilateral lower extremity amputations is a challenging problem because of the difficulty with using the standard fracture table positioning for reduction. Case reports have documented successful reduction and fixation of intertrochanteric fractures in below-the-knee amputees by securing the stump to an inverted fracture boot and connecting the boot to a standard fracture table to achieve reduction [1], [2].

However AKA stumps cannot be effectively secured to the fracture boot. We demonstrate in our case that effective traction and alignment can be obtained using 2 femoral distractors, one placed anteriorly and one placed laterally, with both applying tension across the hip joint.

There is little in the literature in general on the management of displaced hip fractures proximal to an AKA. Displaced femoral neck fractures above an AKA can be managed with arthroplasty to avoid the issues with fracture reduction. Rotational control of the stump when performing hip arthroplasty can be accomplished with a bone clamp or Schanz pin in the either the distal femoral stump or greater trochanter as documented in case reports [3], [4], [5], [6]. A major challenge occurs when effective traction is needed to obtain reduction of a displaced intertrochanteric hip fracture proximal to an AKA stump. While total hip arthroplasty using calcar-replacing stems with trochanteric reattachment is an option in these cases, this may be too extensive a surgery for these patients. Furthermore, periprosthetic infection risks the viability of the entire stump. Infection of an AKA stump with or without a total hip prosthesis places the patient at risk for a hemipelvectomy.

The literature has few case reports describing techniques for obtaining reduction in displaced hip fractures proximal to an AKA [7], [8], [9], [10]. Berg and Bhatia described using a distal femoral traction pin connected to a fracture table to stabilize a nondisplaced femoral neck fracture with extension into the shaft. However traction was not required as the fracture was only visible on MRI [8]. If substantial traction was required there is risk of pin cutout through osteoporotic bone and skin risking infection of the stump. Aquil and colleagues reported fixation of a varus displaced intertrochanteric fracture in a 75-year-old man with an ipsilateral AKA using the thigh support of the fracture table. They performed fixation in situ using a sliding hip screw. No follow up radiographs were presented [7]. Davarinos and colleagues reported fixation of a nondisplaced intertrochanteric fracture proximal to an AKA in a 51-year-old man with a sliding hip screw. They used adhesive fabric tape to secure the stump to the distal end of the fracture table [10].

The technique we describe here allows for controlled restoration of length, alignment, and rotation of the intertrochanteric fracture. The pin placement does not interfere with sliding hip screw placement. Furthermore, the entire stump is in a secure position on the operating room table. We were able to achieve reduction of a displaced intertrochanteric hip fracture with this technique with a good final outcome for the patient.

Statement of informed consent

The patient was informed that data concerning the case would be submitted for publication, and the patient agreed.

Sources of financial support

None.

Conflict of interest

None.