We have reviewed the long-term results of 22 patients (23 fusions) with fractures of the os calcis, who had subtalar arthrodesis with correction of the deformity between 1975 and 1991. The mean follow-up was nine years (5 to 20). All patients were evaluated according to a modified foot score. A radiological assessment was used in which linear and angular variables were measured including the fibulocalcaneal abutment, the height of the heel and fat pad, the angle of the arch and the lateral talocalcaneal and the lateral talar declination angles. The technique used restores the normal relationship between the hindfoot and midfoot and corrects the height of the heel. This leads to better biomechanical balance of the neighbouring joints and gives a favourable clinical outcome. The modified foot score showed a good or excellent result in 51% of the feet. Residual complaints were mostly due to problems with the soft tissues. Subjectively, an excellent or good score was achieved in 78% of the cases. After statistical analysis, except for the height of the heel and the degenerative changes in the calcaneocuboid joint, no significant difference was found in the measured variables between the operated and the contralateral side.
From 1975 to 1990 we performed subtalar or triple arthrodesis on 54 patients; 48 of them were reviewed after a mean follow-up of 10 years (6 to 15). There were 17 subtalar fusions in 14 patients and 37 triple arthrodeses in 28 patients. We assessed tibiotalar ankle function using the criteria of Mazur which gives a points score of a maximum of 100. Radiological evidence of degenerative change was graded on a scale of 0 to 4. The mean Mazur score was 85 for the subtalar fusions and 78 for the triple arthrodeses. The radiological score showed no degenerative changes in 36 feet (24 triple and 12 subtalar arthrodeses) and an increase of one grade in 14 feet (10 triple and 4 subtalar), of two grades in three feet (all triple arthrodeses) and of three grades in one foot after a subtalar arthrodesis. We found no statistically significant difference in the radiological score in unilateral fusions between feet with subtalar and triple arthrodeses and the contralateral foot. In all four feet which showed an increase in degenerative changes of two or more grades, there was an abnormality of the tibiotalar joint before the fusion operation. Of the 14 feet which showed an increase of one grade, there was a similar increase on the contralateral side in nine. Our findings show that subtalar or triple arthrodesis has little adverse influence on the function of the tibiotalar joint, even after many years.
