Introduction: Congenital tarsal coalition is one of the most prevalent (1–6%) anomalies of the hindfoot and midfoot. Its etiology is unknown. By definition there are boney, cartilaginous or fibrous brigdes between 2 bones of the hindfoot and midfoot, which are classified by their localization; the most common coalitions are calcaneonavicular (53%) and talocalcaneal (37%).

Patients and Methods: From 2001 to 2007 28 patients with 37 coalitions had surgery at the Orthopedic Hospital Vienna-Speising.

32 calcaneonavicular coalitions were surgically excised and an autogenous free fat graft was interponed to prevent a relapse. 1 calcaneonavicluar coalition also had an interposition of the extensor digitorum brevis after resection, while 1 calcaneonavicular coalition had lengthening of the short peroneal tendon in addition to excision and autogenous free fat graft. 1 calcaneonavicular coalition had to have an arthrodesis of the talocalcaneal joint.

From 2 talocalcaneal coalitions 1 had excision the other 1 talocalcaneal arthrodesis.

Both of the coalitions that had arthrodesis had short-leg plastercasts for 12 to 13 weeks.

For patients with bilateral coalition pedobarography was performed and the foot that had been treated compared to the untreated contralateral side. For these patients the AOFAS ankle and hind foot score and pain according to the VAS were evaluated.

Results: 22 coalitions that had had surgery were uncomplaining after intervention, including 1 patient who had had arthrodesis. 3 calcaneonavicular coalitions that had had excision and autogenous free fat graft had a relapse within 2 to 3 years. 2 of them had a revision and second-look excision of the bridge.

1 patient showed a suspicious relapse in MRI after excision of a calcaneonavicular coalition. 1 talocalcaneal coaltion that had had excision continued to have pain after surgery. Both patients did not want a revision.

1 patient who was treated by an arthrodesis of the subtalar joint had a fracture of the tibial head, where autogenous bone graft had been taken. Osteosynthesis of the tibia was performed.

4 patients had pain after excision of a calcaneonavicular coalition but could be relieved by conservative treatment.

For 5 patients adequate follow up is still pending due to short interval to surgery.

Pedobarography showed tendecies of improved pressure distribution of the treated feet that were not significant.

Conclusion: Excision and autogenous free fat graft should be first approach to surgery of symptomatical congenital tarsal coalitions for whom conservative treatment was not satisfying. When resected sufficiently the rate of relapse of the boney, cartilaginous or fibrous bridge is 7%. Depending on the patients age, the size of the affected area of the joint (50%) and secondary arthrotic changes of the joint an arthrodesis of the talo-calcaneal joint should be performed.