Calcaneonavicular coalition: treatment by excision and fat graft

Symptomatic calcaneonavicular coalitions treated with resection and interposition of the extensor digitorum brevis (EDB) muscle often have unpredictable improvement of symptoms. Concerns with regard to skin cosmesis from a bony prominence on the lateral aspect of the foot and inadequate filling of the resection gap potentially causing reossification have motivated us to use fat graft interposition instead. The purpose of this study was to describe our surgical technique and report our clinical and radiographic outcomes for fat graft interposition after resection of a calcaneonavicular coalition.

A retrospective review of all pediatric patients surgically treated with a calcaneonavicular coalition resection from January 1999 to December 2006, was performed. Presenting symptoms and examination findings were recorded. Postoperative examinations and imaging studies were evaluated to grade reossification, and functional outcomes were assessed for all patients with minimum 1-year postoperative follow-up. In addition, a cadaveric study was performed to compare the efficacy of EDB and fat graft interposition in terms of filling the postresection gap.

Foot pain was the most common presenting complaint, though limitation of activities, stiffness, preoperative hindfoot malalignment, and associated injuries were also frequently observed. One year after resection, 87% of the patients returned to sport or their past activities, whereas 5% had symptomatic regrowth requiring repeat resection. Seventy-four percent had improvement of subtalar motion and 82% had improvement of plantarflexion; which was identified as an additional clinical sign of a calcaneonavicular bar. Preoperative pain averaged 7 of 10, whereas postoperative pain averaged less than 1 of 10 at rest, while walking, and with activities. The cadaveric study showed that the EDB was able to fill on average only 64% of the resected gap, leaving approximately 10 mm of the plantar gap unfilled.

Reossification and reoperation rates with fat graft interposition in our series were lower than in most published reports of EDB interposition. Ankle and subtalar motion improved in a vast majority of the patients, and most patients returned to sport without requiring further surgery. Resection of a calcaneonavicular coalition with interposition of fat graft, when meticulously performed, is an effective way to relieve symptoms, restore subtalar motion, and return patients to activities, while preventing reossification.