The ankle injury--indications for the selective use of X-rays.

The radiograph is rapidly superseding the clinical examination as the diagnostic tool for acute ankle injuries. Twenty-four independent variables which might help distinguish between soft tissue injuries and fractures at the ankle were identified and then used prospectively to study 150 consecutive patients with ankle injuries. Nineteen patients had fractured ankles (12.7 per cent) and 131 (87.3 per cent) had soft tissue injuries. Only the patient's ability to bear weight on the injured ankle and the presence of tenderness over the lateral aspect of the ankle below the malleolus proved to be helpful. When these 2 signs were present together, regardless of all other variables, there was a 97.5 per cent probability of soft tissue injury P less than 0.005). This study suggests that careful patient assessment will permit more discriminating use of ankle X-rays.