Value of Ultrasound for Stability Assessment of Isolated Lateral Malleolar Fractures Compared to Stress Radiography and Arthroscopy

BACKGROUND: This study was performed to evaluate the value of using ultrasound for stability assessment of isolated lateral malleolar fractures compared to simple X-ray, stress radiography, and arthroscopy. METHODS: This is a prospective cohort study with 25 consecutive patients who underwent an arthroscopic examination and subsequent surgery for isolated lateral malleolar ankle fractures. Before operation, simple and external rotation stress radiographs were obtained. Ultrasound was performed to assess the medial deltoid ligament prior to operation. Arthroscopic findings were used as reference standards. Sensitivity, specificity, and positive and negative predictability were calculated and compared using receiver operating characteristic (ROC) curve analysis for simple radiography, stress radiography, and ultrasound examination. RESULTS: The sensitivity and specificity of ultrasound for tears of the deep deltoid ligament were 94.74% and 66.67%, respectively. But, they were both 100% for complete tears of the ligament. ROC curve analysis showed that the ultrasound examination was significantly more accurate than simple and stress radiography. CONCLUSIONS: Ultrasound could be used to assess the instability of isolated lateral malleolar fractures. Commonly used stress radiography appears to overrate the need for operative treatment.