Limb salvage reconstruction of the ankle with fusion and simultaneous tibial lengthening using the Ilizarov/Taylor spatial frame.

Abstract

Despite early appropriate treatment with modern orthopedic trauma surgery protocols, distal tibia and ankle injuries do not uncommonly result in posttraumatic ankle arthritis. Ankle fusion offers reliable pain relief and improved function for many of these patients [1]. Ilizarov reconstruction with ankle arthrodesis has been used successfully to treat the more complex ankle pathology in many cases as an alternative to amputation [2–7]. These complex fusions can be limb salvage undertakings, as the treatments are often complicated by the presence of bone loss, osteomyelitis, associated deformity, and a poor soft tissue envelope with compromised healing potential. Most of these patients had failed multiple previous surgeries including open reduction with plates and screws, attempted ankle fusion, total ankle replacement, and external fixation with limited internal fixation. Various techniques for achieving complex ankle fusion have been reported including fixation with crossed lag screws, a fixed angle plate and screws, retrograde intramedullary nailing, and external fixation [8–16]. Although all of these methods can be used to obtain bony union, bone loss remains a challenging problem in these patients. Leg length inequality commonly results in altered gait and symptomatic malalignment of the pelvis and spine. Large shoe lifts are difficult to manage and poorly tolerated, and compliance is low. The use of structural allografts with internal or external fixation has been advocated to reestablish length [17–19]. Problems with graft collapse, infection, and nonunion accompany this technique. Proximal tibial lengthening provides an alternative means of equalizing leg lengths and improving function and self-perception. The need to implant large devitalized bone graft at a compromised healing site is obviated by the use of the patients own bony regenerate at a separate lengthening site. This technique allows for bony contact at the fusion site without intervening graft that is thought to facilitate union. In cases of severe bone loss, acute shortening to obtain bony contact at the fusion site may not be possible, and bone transport may become necessary. The use of circular fixation for ankle fusion was first described by Ilizarov [20]. The rationale for using the Ilizarov frame is to provide fixed angle stable fixation of the bone fragments, a percutaneous approach that is particularly useful in the presence of poor skin, and avoid the use of internal implants in the presence of infection. Using these frames, chronic deformity can be corrected with reduced risk of soft tissue complications, compression can be maintained throughout the postoperative period, and limb function is preserved through early weight bearing and physical therapy. The Taylor spatial frame (TSF) is a newer version of the Ilizarov fixator and has greatly simplified our ability to combine fusion with gradual simultaneous deformity correction and/or lengthening. Lengthening at a proximal osteotomy site can be done at the time of ankle fusion or staged a few weeks later as the clinical situation dictates. Staged lengthening requires returning to the operating room (OR) for frame modification and osteotomy. In complex ankle arthrodesis, it is not uncommon to be faced with having to close a large defect that is not amenable to bone grafting. The Ilizarov/TSF can be used to simplify this otherwise daunting problem by performing a gradual shortening with or without simultaneous lengthening or bone transport.