[Functional results of tibio-tarsal arthrodeses. Apropos of 52 reviewed cases].

Fifty-two patients with ankle arthrodesis were reviewed after an average follow-up of 7 years with a range between 2 and 22 years. Two-thirds of the patients had good results and 1 in 4 had fair results. In 4 cases there were bad results. Thirty-seven patients could walk without any limitation thanks to mobility of the mid-tarsal joint. Most of the patients developed radiological arthrosis of the subtalar joint with limited movement in 29 instances. In contrast, hypermobility of the mid-tarsal joint was present in almost half of the cases. Good functional results were related to the preservation of mobility in the subtalar and mid-tarsal joints. The time required to obtain a good functional result was about one-and-a-half years. After this the results were stable, provided that the ankle fusion was in a good position. Most of the poor results were related to arthrosis of the sub-talar joint or trophic changes. Secondary extension of fusion to other joints was deceptive. It is concluded that combined arthrodesis of the tibio-talar and sub-talar joints should be done only in cases of severe arthrosis. In other cases, the mobility of the sub-talar and mid-tarsal joints should be preserved.