We have reviewed 42 of 52 consecutive patients at an average of 14 years after a tenodesis based on Evans' operation performed for chronic lateral instability of the ankle. Only 21 patients (50%) had satisfactory long-term functional results, and 12 patients with satisfactory early results had deteriorated after three to six years. Stress radiographs were used to measure anterior talar translation and talar tilt, and a good correlation was found between function and mechanical stability. Talar tilt had been controlled more successfully than anterior translation. Marginal osteophytes were found in most ankles, and were larger and more numerous in those with the greatest instability.