Aims

We hypothesized that there is no difference in the clinical and radiological outcomes using local bone graft versus iliac graft for subtalar distraction arthrodesis in patients with calcaneal malunion. In addition, using local bone graft negates the donor site morbidity.

Distraction bone-block arthrodesis has been advocated for the treatment of the late sequelae of fracture of the os calcis. Between 1997 and 2003 we studied a consecutive series of 17 patients who had in situ arthrodesis for subtalar arthritis after fracture of the os calcis with marked loss of talocalcaneal height. None had undergone any previous attempts at reconstruction. We assessed the range of dorsiflexion and plantar flexion and measured the talocalcaneal height, talocalcaneal angle and talar declination angle on standing lateral radiographs, comparing them with the normal foot. The mean follow-up was for 78.7 months (48 to 94).

The mean American Orthopaedic Foot and Ankle Society hindfoot score improved from 29.8 (13 to 48) to 77.8 (48 to 94) (Student’s t-test, p < 0.001). The mean loss of talocalcaneal height was 10.3 mm (2 to 17) and the mean talar declination angle was 6.7° (0° to 16°) which was 36% of the normal side. One patient suffered anterior ankle pain but none had anterior impingement. Two patients complained of difficulty in ascending slopes and stairs and four in descending. The mean ankle dorsiflexion on the arthrodesed side was 11.6° (0° to 24°) compared with 14.7° (0° to 24°) on the normal side, representing a reduction of 21.1%. The mean plantar flexion on the arthrodesed side was 35.5° (24° to 60°) compared with 44.6° (30° to 60°) on the normal side, a reduction of 20.4%.

These results suggest that anterior impingement need not to be a significant problem after subtalar arthrodesis for fracture of the os calcis, even when the loss of talocalcaneal height is marked. We recommend in situ arthrodesis combined with lateral-wall ostectomy for all cases of subtalar arthritis following a fracture of the os calcis, without marked coronal deformity, regardless of the degree of talocalcaneal height loss.