Comparative Assessment of Midfoot Osteoarthritis Diagnostic Sensitivity Using Weightbearing Computed Tomography vs Weightbearing Radiography
Authors: Steadman Jesse , Sripanich Yantarat , Rungprai Chamnanni , Saltzman Charles L. , Barg Alexej 
Published: November 2020

Category: Midfoot/Forefoot; Other Introduction/Purpose: Osteoarthritis (OA) of the midfoot can elicit significant pain, disability, and decreased quality of life in affected patients. Therefore, correct diagnosis and appropriate, timely interventions towards this degeneration is essential. Currently, weightbearing radiography (WBR) has been widely accepted as the standard method in assessing midfoot OA. However, the complex structural anatomy of this region poses unique challenges in its visualization due to the obscurance caused by the overlapping osseous structures present when observed in a two-dimensional perspective. Weightbearing computed tomography (WBCT), providing a relatively clearer visualization of the midfoot could also be used for evaluation. This study aims to perform a single center, retrospective, intra-patient analysis identifying the discrepancy in midfoot OA diagnostic sensitivity among the two imaging modalities (WBCT vs. WBR). Methods: After gaining approval from an internal review board, a retrospective analysis of patient electronic health records was performed to assess the discrepancy of midfoot OA diagnostic sensitivity among WBCT and WBR. The radiological interpretation (RI) of 761 consecutive patient WBCT images were systematically assessed for OA diagnosed in 3 midfoot joint groups (Chopart group; 2 joints, midfoot group; 6 joints, Lisfranc group; 5 joints). A case was considered positive for OA if the WBCT RI contained any explicit mention of midfoot OA or any reported signs of the pathology including mild, moderate, or severe degeneration, joint space narrowing, osteophytic changes, spurring, cystic changes, or sclerosis in at least one of the aforementioned joint groups. After an appropriate washout period, the observer then synonymously reviewed the WBR RI of each positive OA case. A sensitivity metric was calculated for the OA incidence and severity discrepancy between the two imaging modalities. Results: A total of 302 (mean age, 56.0 +- 16.0 years; 140 left and 162 right) feet were assessed in this study. 244 cases of Chopart OA were detected on WBCT RI, where only 184 cases were detected on the WBR RI of the same feet, resulting in a diagnostic discrepancy of 24.6%. In the midfoot joint group, WBCT RI and WBR RI detected 96 and 67 cases of OA respectively, yielding a 30.2% discrepancy. Finally, in the Lisfranc joint group, the WBCT and WBR RI detected 174 and 129 cases of OA, respectively, showing a 25.9% discrepancy in diagnosis. Additionally, the OA severity was downgraded between modalities in 7.0%, 4.2%, and 8.0% for the Chopart, midfoot, and Lisfranc joint groups, respectively. Conclusion: After assessing 244 Chopart, 96 midfoot, and 174 Lisfranc cases of OA detected by WBCT, a significant discrepancy has been observed in the diagnostic abilities of midfoot OA among the two imaging modalities studied. With this difference realized, in addition to the recent higher availability, decreasing cost, and low radiation exposure offered by WBCT, this imaging modality may have the ability to aid physicians considerably in their clinical practice. Detecting and correctly diagnosing the severity of this pathology may lead to more appropriate treatment options, lower complication rates, and better patient outcomes.