Tarsal coalitions in the adult population: does treatment differ from the adolescent?

There is a paucity of information on adult coalitions without large, well-designed outcome studies. Current recommendations are thus similar to those for adolescents. Based on the available literature, current recommendations include an initial trial of adequate nonoperative treatment in symptomatic coalitions. Unlike adolescent coalitions, nonoperative treatment may be even more effective in the adult patient as many are asymptomatic or discovered after injury. If nonoperative treatment fails, then surgical intervention is considered and tailored to the location of the coalition, existing advanced arthrosis, and any existing deformity. Similar to the adolescent, surgical treatment for adult calcaneonavicular coalitions typically involves an attempt at resection with some type of interposition. Resection can be attempted for talocalcaneal coalitions that do not present with advanced arthrosis or significant hindfoot malalignment. For those patients with advanced arthrosis, more than 50% involvement of the joint hindfoot malalignment, subtalar or triple arthrodesis is recommended. The decision between resection and arthrodesis is controversial in the adolescent population. With few outcome studies in adults, it is even more difficult to make definitive treatment recommendations; however, the indications for resection are likely even more limited. It is likely that the adult subtalar coalition that becomes symptomatic and fails nonoperative treatment will require arthrodesis for full pain relief and improvement in objective outcome measures, such as the AOFAS hindfoot score. Our treatment algorithm focuses first on a trial of nonoperative treatment of at least 3 months regardless of coalition location. After failed nonoperative treatment, calcaneonavicular coalitions are in most cases treated with excision and interpositional fat graft. For talocalcaneal coalitions, resection is offered to patients with neutral hindfoot alignment, some preservation of subtalar joint motion and no adjacent joint arthrosis. The patients are advised that the outcome after resection of talocalcaneal coalitions is less predictable than resection of calcaneonavicular coalitions. Those patients with absent subtalar motion and relatively normal hindfoot alignment are candidates for in situ fusion of the subtalar joint. For those patients with greater than 15° of valgus hindfoot malalignment on a weight-bearing hindfoot alignment view or adjacent joint arthrosis, a triple arthrodesis is recommended with or without medial displacement osteotomy of the calcaneus. Adjacent joint arthrosis may be determined by radiographs, CT scan, or preoperative MRI.