Can American Orthopaedic Foot and Ankle Society (AOFAS) score prevent unnecessary MRI in isolated ankle ligament injuries?

Abstract

Introduction and objective: Ankle injuries are the most common musculoskeletal injuries. Its incidence is also high among sports injuries. Direct X-ray, ultrasound and MRI can be requested after the history and physical examination in the patient who presents with ankle ligament injury. Some classifications are used for requesting direct X-ray after ankle injury. Since clear limits are not specified in the literature for MRI, the rate of unnecessary MRI examinations is high. We argue that the decision can be made according to the AOFAS score to be checked before MR is requested, and thus unnecessary MR requests can be reduced.

Material and method: Ankle MRI images of patients who underwent ankle MRI due to ankle trauma between January 2018 and December 2020 were scanned. 328 patients who met the criteria were included in the study. Patients with AOFAS scores in their outpatient clinic records were identified. AOFAS scores of patients with at least one ligament injury and those with normal MR images were statistically compared. Sensitivity and specificity were determined for the AOFAS score using ROC analysis.

Results: Patients with ligament damage as a result of MRI examination were 21.3% (n=70), and patients without any ligament damage were 78.7% (n=258). There was a statistically significant difference in terms of AOFAS between the group with ligament damage and the group without ligament damage (p< 0.05). In the ROC analysis, the AOFAS threshold value for MR request was determined as 80.5 (84.3% sensitivity and 72.3% specificity). Based on the determined threshold value, 73 patients who had unnecessary MRI would have been eliminated, thus reducing the number of MRIs by 42.6%.

Conclusion: The AOFAS scores of patients with ligament damage were statistically significantly lower than those of patients without ligament pathology. Unnecessary MRI can be significantly prevented by using the AOFAS score in ankle traumas without bone fractures.