Intraoperative Findings of Lateral Ligament Avulsion Fractures and Outcome After Refixation to the Fibula.

BACKGROUND

An acute ankle sprain can result in a bony avulsion of the lateral ankle ligaments. The extent of concomitant lesions and subsequent instability patterns are not clearly understood. The high incidence of old avulsion fractures found in symptomatic chronic ankle instability may indicate the need for primary fixation.

METHODS

Ten patients (5 male, 5 female; mean age, 34 years; range, 15-64 years) with bony avulsion fractures of the fibula after acute ankle sprains were included. All patients were treated after a mean of 7.7 days (range, 2-17 days) with screw fixation of the fragment to the fibula. Clinical and radiographic assessments were performed, and the extent of ligament injury was documented.

RESULTS

The anterior talofibular ligament and calcaneofibular ligament were found to be attached to the avulsion fragment. The average size was 6.3 mm (range, 4-9 mm) in width from anterior to posterior and 5.2 mm (range, 4-7 mm) in length from superior to inferior. The displacement of the fragment increased under varus stress. Two patients had cartilage lesions in the lateral talus. After a mean follow-up period of 2.4 years (range, 2-4 years), all were clinically and radiographically stable, and patients were satisfied.

CONCLUSIONS

It was observed arthroscopically that the anterior talofibular ligament and calcaneofibular ligament were attached to the fragment. This is critical because motion between the fragment and the fibula may prevent spontaneous healing. Primary fixation of the fragment prevented rotational instability and was efficient to restore function and stability.

LEVEL OF EVIDENCE: Level IV, retrospective case series.