[Tibiotarsal arthrodesis: value of external fixator associated with in situ cancellous bone graft. Initial results apropos of 18 cases].

Tibio-talar arthrodesis poses some problems and the most frequent are non-union and varus malalignment of the ankle joint. The aim of this report was to present a new technique of ankle joint arthrodesis. The principles of this procedure are as follows: firstly, the external fixation (A.L.J.) is framed, secondly, perpendicular cuts are made in the tibial plafond and talus through an anterior longitudinal approach; and thirdly, the gap is filled with cancellous bone graft which is taken preferably on the iliac crest. If the back-foot is not correctly lined up preoperatively, the external device is framed in two steps: the first step consists in putting the pins. Then perpendicular cuts are made, and the back-foot is correctly lined up using calcaneal pins. The second step consists in connecting tibial pins and foot pins using union-rods. The last step of the procedure is to fill the gap with cancellous bone graft. The external fixation device is removed after 45 days and a shortleg walking cast is put for 45 days. Between 1981 and 1992, 18 arthrodesis were performed on various diagnosis: 9 post-traumatic tibio-talar osteoarthritis, 4 residual neurologic diseases, 2 rheumatoid arthritis and 3 recent post-traumatic lesions. There were 17 patients (one bilateral case), 4 females and 13 males; the middle age at the time of operation was 44.5 years (20 to 60) and there were 10 right ankles and 8 left. The tibio-talar arthrodesis was performed alone in 14 cases, but it was associated with a talo-calcaneus arthrodesis in 4 cases. The after care was without complications except 3 pins infection which cured with antibiotics. All the cases had a good bony union within 3 to 6 months and the orientation of the backfoot was always satisfactory without varus malalignment. All the patients could put one's shoes without having recourse to orthopaedic shoes. In conclusion, this operative procedure seems to minimize the problems and pittfalls of the ankle arthrodesis.