Long-term results of arthrodesis for osteoarthritis of the ankle.

A bone graft in the shape of a triangular prism was taken from the anterior surface of the tibia and used in the arthrodesis in 43 joints of 42 patients with primary and secondary osteoarthritis of the ankle. The modified anterior sliding inlay graft method was used. The average period of external immobilization was 5.8 weeks (range, 27-84 days), and followup ranged from 2 years 4 months to 14 years 11 months (average, 7 years 2 months). Nonunion was detected in three (7%) patients: one patient returned to work without additional treatment, and the other two patients underwent followup surgery within 7 months, and bony union was achieved. The final rate of nonunion was 2.3%. After the operation, excellent alleviation of pain was obtained. However, dorsiflexion of the foot decreased from the preoperative average value of 10.5 degrees to the postoperative value of 4.2 degrees, and plantar flexion also decreased from the preoperative value of 24.7 degrees to the postoperative value of 14 degrees. In addition, the range of motion of the subtalar and Chopart joints gradually improved with little effect on daily living activities. The most appropriate position of arthrodesis of the ankle appears to be in the neutral position between dorsal and plantar flexion. In addition, the varus and valgus angle of the hindfoot should be in a neutral or slightly valgus position. Degenerative arthritis developed and advanced in the subtalar joint in 32.5% of the patients, and these degenerative changes were exacerbated in many patients if such changes were present before surgery. Tibial stress fracture occurred in two (4.7%) patients as a complication that was specific to the current surgical method. Thus, the surgical procedure was modified to prevent the onset of tibial stress fracture.