To compare results of the modified Brostrom procedure and the Chrisman-Snook procedure for chronic lateral ankle instability.

Twenty-eight patients (30 ankles) who underwent 20 modified Brostrom procedures or 10 Chrisman-Snook procedures were available. Follow-up averaged 3.2 years (1.3-5.4 years). Clinical results were graded according to the AOFAS clinical rating system. The talar tilting angle was also measured.

Clinical results were rated as excellent in 15, good in 4, and fair in 1 ankle after the modified Brostrom procedure, and excellent in 7, and good in 3 ankles after the Chrisman-Snook procedure. Three complications occurred after the Chrisman-Snook procedure; delayed wound healing in 1 ankle, and transient neuralgia in 2. Mean talar tilting angle was improved from 17.4±6.6degrees to 6.6±1.2degrees by the modified Brostrom procedure, and from 15.6±5.9degrees to 3.0±1.1degrees by the Chrisman-Snook procedure.

Significant differences were found in the clinical results obtained using the two procedures, and good function was obtained in a high percentage of patients. The procedure of choice should be decided upon based on the patient's condition and the doctor's preference.