SLR - February 2023 - Jini Philip, DPM
Title: Can American Orthopaedic Foot and Ankle Society (AOFAS) score prevent unnecessary MRI in isolated ankle ligament injuries?Reference: Kandemir V, Akar MS, Yiğit Ş, Durgut F, Atiç R, Özkul E. Can American Orthopaedic Foot and Ankle Society (AOFAS) score prevent unnecessary MRI in isolated ankle ligament injuries? J Orthop Surg (Hong Kong). 2022 Sep-Dec;30(3)
Level of Evidence: 4
Reviewed By: Jini Philip, DPM
Residency Program: Hoboken University Medical University Medical Center – Hoboken, NJ
Podiatric Relevance: Imaging studies requested after ankle injuries, the most common musculoskeletal injuries, include X-rays, ultrasounds, and MRIs. The lack of classification and limits set for when to request an MRI examination can lead to increased cost, labor, and delay in diagnosis. This study aims to evaluate whether unnecessary MRI examinations orders can be reduced by utilizing the AOFAS score.
Methods: This study analyzed 171 patients with and without ligamentous pathologies. Patients had MRI scans with a slice thickness of 3 or 6 mm. After reevaluation, the patients were classified into the low ankle ligament injury, high ankle ligament injury, medial ligament injury, or normal pathology group. Preexisting AOFAS scored were used for comparison and the average score was determined for each group. The Chi-square, student t-test, and ROC analysis were performed.
Results: MRI scans were taken on an average of 6.41 weeks after injury. The student t-test revealed a statistically significant difference between the AOFAS scores of the 171 patients and the presence of ligament injuries (p<0.001). 10.3% of patients had LCL injury, 1.5% had MCL injury, 8.2% had syndesmotic injury, 0.6% had both LCL and MCL injuries and 0.6% had damage in all ligaments. The AOFAS scores of each group with ligament injuries compared to the normal group were statistically significant (p<0.05). The Chi-square test revealed a statistically significant difference between the gender of patients and AITFL injuries (p<0.05) while the other ligament injuries had no relationship with gender. The ROC analysis resulted in an AOFAS threshold value of 80.5.
Conclusions: The authors recommend the AOFAS score (threshold 80.5 and below) as a criterion for ordering an MRI examination to evaluate possible ankle injuries. They conclude that time expended, and financial loss decrease when the AOFAS score is used as a screening tool to determine the need for MRI examinations. Unnecessary MRI scans can also lead to an increase in delay of diagnosis in cases where an MRI is needed. In this study, no pathology was detected on 78.7% of the ordered MRI scans. Using the AOFAS threshold of 80.5, determined from the ROC analysis, only 87 of the 171 patients in this study would receive MRI orders. Of those 87 patients, 59 would be diagnosed with pathologies and 28 patients would have a normal MRI result. MRIs ordered were decreased by 42.6% by utilizing the AOFAS score. However, using the AOFAS threshold, 11 patients who had ligamentous injuries wound not have received an MRI. The most common injured ligament was the ATFL with the mechanism of action being ankle inversion. If not correctly diagnosed and treated, chronic ankle instability, osteoarthritis, and anterolateral impingement syndrome may result. In this study, the AOFAS threshold of 80.5 is shown to be a resource to reduce workload and cost. However, the 11 missed ankle ligamentous pathologies have serious implications. The AOFAS threshold presented in this study may be used; however, this should not diminish the physician’s clinical judgement and physical examination findings for determining whether MRI examination orders are needed.