Radiographic instability of the ankle joint after Evans' repair

Forty-two unstable ankle joints were treated surgically by Evans' operation. The clinical postoperative results were correlated with the objective radiological stress examinations. The mean age of the patients was 29 years (15-60 years). The clinical and radiological follow-up examinations were performed 6 months after the operation. In the stress X-ray examinations a modified stress frame was used. Clinical instability was noted in four patients. In the radiological examination one patient had a pathological finding in the talar tilt test and 18 patients in the anterior drawer sign test. The radiological instability correlated poorly with the subjective end results. Six patients were estimated to have a poor result of the operation. Five of these patients had a positive anterior drawer sign in the stress X-ray examination and one had degenerative changes in the ankle. Although Evans' repair is a simple and reliable method of reconstructing ruptures of the lateral ligaments of the ankle joint, it is associated with a relatively high frequency of positive anterior subluxation on radiological stress examination. This finding can be explained by the anatomical and geometrical factors on the lateral side of the ankle joint.