Foot function after subtalar distraction bone-block arthrodesis. A prospective study.

Subtalar distraction bone-block arthrodesis for malunited calcaneal fractures was performed in 31 patients (26 men, five women), with a mean age of 38.5 years. The mean time from injury to arthrodesis was 36 months. There were no cases of nonunion. One patient had an early dislocation of the bone block requiring a repeat arthrodesis, and one had a soft-tissue infection. The mean AOFAS hindfoot score improved significantly from 23.5 before operation to 73.2 at a mean follow-up of 33 months (p > 0.001). Compared with the unaffected side, the talocalcaneal height was corrected by 61.8%, the talus-first metatarsal axis by 46.5%, the talar declination angle by 38.5% and the talocalcaneal angle by 35.4%. Dynamic pedobarography revealed a return to normal of the pressure distribution during roll-over and a more energetic gait. The distribution of local transfer of load correlated well with the AOFAS score. The amount of correction of the heel height correlated with a normal pattern of pressure transfer on the heel (p < 0.05).