Abstract

The authors have reviewed 20 cases of valgus flatfoot deformity in the adult, secondary to insufficiency of the tibialis posterior tendon, which were treated by triple arthrodesis from 1983 to 1998. The longitudinal arch was flat grade 3 in 18 cases and grade 2 in two. The rearfoot was in valgus in all cases. Dorsal flexion of the ankle was limited to 5 degrees with a short Achilles tendon in 10 cases Djian-Annonier's angle was 134 degrees on average. The talocalcaneal divergence was 32 degrees. Diffuse osteoarthritis was present preoperatively in 14 cases. Fusion of the arthrodesis was achieved in 18 cases. There were two nonunions: one affecting the talonavicular joint, and the other, the talonavicular and calcaneocuboid joint. Results evaluated according to Kitaoka's criteria were excellent in 35%, good in 35%, fair in 20% and poor in 10%. Xrays showed progression of osteoarthritis. These results were not as good as in Fortin and Waling's series but we did not use iliac grafts. There was no instance of talus necrosis. The nonunion rate was higher than in other series at the talonavicular level. In order to improve the results, we now believe that bone resection must be kept minimal and bone grafts should be used, in addition to internal fixation. Triple arthrodesis was found to give good result in the treatment of acquired flat foot deformity due to insufficiency of the tibialis posterior tendon. However on the long term it promotes degenerative changes in neighbouring joints.