A 44-year-old woman sustained a closed injury to her right thigh after she fell down a flight of stairs. Twenty-seven years before, she had been involved in a road traffic collision and had undergone a right-sided transtibial amputation for a severe open tibial fracture. An associated ipsilateral femoral fracture was treated in traction.
Until her recent injury, she worked full time as a landlady in a pub and was independently mobile with a transtibial prosthesis. She smoked about 30 cigarettes per day.
Radiographs (Figs. 1, 2) revealed a comminuted distal femoral fracture, just below the site of a previous malunion (varus with posterior translation).
The manner of the malunion posed technical difficulties with the usual methods of internal stabilization for fractures of this region. Options for treatment were discussed with the patient. A decision was taken to use a circular external fixator based on the rationale of minimally invasive surgery coupled to facilitation of early functional loading. An Ilizarov frame was applied with two levels of fixation in the proximal segment. The distal segment of the femur was too short for two levels of fixation, prompting the need for stabilization across the knee with an additional level of fixation in the tibial stump (Fig. 3).
The patient was seen by a prosthetist a week after application of the Ilizarov frame. A 12-mm copolymer polypropylene sheet was fixed to the tibial ring using four 120-mm rods. The prosthetic shin was then attached via a male pyramid connector to the prosthetic dynamic sach foot. This enabled the patient to take weight on the leg (Figs. 4, 5), with eventual independent ambulation without walking aids.
Autologous iliac crest bone grafting was performed at 3 months for tardy evidence of radiological healing. Radiological union (Fig. 6) was achieved at 5 months, and the fixator was removed 6 months after application. The patient was able to use her original prosthesis, and has reported no problems since then.
This woman presented a unique problem in that she had a comminuted fracture just below a varus and posteriorly translated malunion, which prevented straightforward internal stabilization by either plate or intramedullary nail. Closed retrograde nailing would have meant the addition of an osteotomy close to the comminuted fracture. The canal appeared sclerotic and difficult to negotiate. Furthermore, this woman had no symptoms from her preexistent malunion and mobilized well despite this.
Skeletal traction would not be appropriate because of the likely length of hospital stay.
Circular external fixation allows stabilization to be achieved with minimal disruption of the inherent tissue and bone viability, as well as providing stability to enable early functional use. However, the challenge of facilitating the latter in a transtibial amputee required fashioning a frame construct that would be amenable to attachment of a prosthesis. The decision to bridge the knee through use of wires in the tibia thus not only provided additional control of the fracture site but also enabled prosthetic fitting.
Case reports in the literature have previously illustrated the use of external fixator techniques for the purpose of lengthening short amputation stumps,1–6 but there are no previous reports of this technique being employed to treat a fracture in an amputee. The necessity to bear weight was biologically and socially important in this case and has been demonstrated previously in lengthening amputation stumps. In 2003, Villarruel et al. outlined how this could be achieved using a Hoffmann external fixator (Stryker Howmedica Osteonics, Geneva, Switzerland),7 but although other studies have alluded to the similar techniques being achieved with circular frames, the details of such have not been outlined. Circular frame techniques used in such fractures in lower-limb amputees have not been reported, nor have the details of the articulation between a prosthetic leg and a circular frame been detailed.
This case illustrates how the biomechanical advantages of stable external fixation coupled to modified prosthetic fitting can effectively accomplish a restoration of independent existence for a transtibial amputee. The added benefit of stimulation through weightbearing in this system has brought a difficult fracture to a successful union in a reasonable period.
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7. Villarruel G, Hercegovics-Perri T, Setoguchi Y, Watts HG. Temporary prosthetic fitting over tibial stump lengthening device. J Prosthet Orthot