Peritalar Osteotomy for Rigid Pes Cavus and Cavovarus

Abstract

Category: Other; Hindfoot Introduction/Purpose: Pes cavus and pes cavovarus deformities create varus loading during stance phase of gait that often presents as lateral ligament instability, peroneal tendon rupture or lateral column overload. When flexible, management ranges from the use of custom foot orthoses or an ankle-foot orthosis, to a combination of soft tissue releases, tendon transfer and/or corrective osteotomy. When rigid, clinical management involves corrective osteotomies or triple arthrodesis. The Ilizarov method of gradual correction of structural bony deformities provides a powerful tool to achieve a stable plantigrade foot in patients with complex multiplanar structural deformities. This investigation presents a method of a continuous multiple bone “peri-talar” osteotomy, combined with acute correction of the multiplanar deformity, for treating severe rigid structural pes cavus and pes cavovarus. Methods: Following IRB approval, patients were identified based on a combination of CPT (Current Procedural Terminology) codes and confirmed by chart review. Standard demographics, etiology of deformity and weight-bearing radiographs (before and after surgery) were reviewed. Perioperative complications, clinical evaluation and type of footwear used were recorded. A favorable clinical outcome was defined as a foot that is ulcer and infection-free, and able to walk in the community with standard oxford shoes. Surgical technique involved an osteotomy from the dorsal calcaneus, carried anterior and inferior for approximately fifty percent of the calcaneus, and then carried anteriorly into the mid cuboid. A second osteotomy through a separate medial incision is made from medial to lateral, splitting the navicular, and connecting to the initial lateral osteotomy. Acute correction of the multiplanar deformity is accomplished. Maintenance of the correction is then achieved with the use of an Ilizarov-like “mitre” circular external fixation construct. Results: 17 patients (three bilateral) were included, with average follow-up of 58.3 (range 12-183) months. One patient developed a postoperative wound infection that required formal surgical debridement. He died of unrelated causes before removal of the external fixator. A second postoperative wound infection was managed with local wound care. One pin-site infection required debridement following removal of the external fixator. Due to the rotational component of the deformities, meaningful measurement of deformity correction could not be accomplished. This clinical outcome was based primarily on the ability to walk without complex bracing. Sixteen of the twenty feet achieved ambulation with standard oxford footwear. Three patients required a short AFO, but were unrestricted community ambulators. A review of the non-standardized x-rays was not able to yield meaningful data. Conclusion: There have been very few clinical reports of surgical correction of patients with severe rigid pes cavovarus or equinovarus deformities. This small series of patients underwent correction of complex rigid pes cavovarus type deformities with a peritalar osteotomy, acute correction of deformity and maintenance of correction with a “mitre frame” circular external fixator. Several proponents of the Ilizarov method have described individual patients with very similar methodology. This small series of patients suggests that one can achieve an acute, or gradual, correction of complex deformity with multiple related osteotomies, and maintenance of that correction with an adjustable circular external fixator.