Treatment algorithm of chronic ankle and subtalar instability.

From 1981 to 1984, 131 reconstructive procedures and 113 Evans tenodesis procedures (1972-1984) were performed for patients with chronic instability of the ankle joint. From 1981 to 1985, 42 Christman/Snook procedures were performed for patients with isolated or combined subtalar instability. Reevaluation was conducted for 223 patients (102 reconstructive procedures, 87 Evans tenodesis procedures, and 34 Christman/Snook tenodesis procedures). The follow-up protocol comprised standard and stress radiograms, subjective patient evaluation, and objective functional data. No patient in either treatment group had clinically important ankle instability. Patients who had undergone the Evans tenodesis had a 3.3 degrees mean less talar tilt than did patients treated with reconstructive procedure. Of 87 patients who underwent Evans tenodesis, 33 had a mean supination deficit of 7.5 degrees. According to the +/- 100 points classification, 90% of the patients in both groups achieved good or excellent results. For subtalar instability, the Christman/Snook techniques resulted in a mean supination deficit of 7.2 degrees in 20 patients. Of 34 patients, 31 were rated good or excellent.