Validity and Reliability of a New Radiological Method to Estimate Medial Column Internal Rotation in Hallux Valgus Using Foot Weight-Bearing X-Ray

BACKGROUND: Medial column internal rotation in hallux valgus (HV) can be measured using weight-bearing computed tomography (WBCT). Anteroposterior weight-bearing foot radiographs' (WBXR) ability to estimate medial column internal rotation in HV was evaluated comparing these measurements with those obtained from WBCT. METHODS: Three observers evaluated WBCT and WBXR of 33 HV feet twice. Medial column internal rotation was measured with WBCT and classified into 3 levels according to WBXR findings. Intra- and interobserver reliability were obtained for WBXR and WBCT, in addition to WBXR-WBCT correlation. RESULTS: WBXR and WBCT intraobserver agreement was substantial and near perfect, respectively (κ 0.79 and 0.84). Their interobserver agreement was excellent (intraclass correlation 0.85 and 0.9, respectively). The WBXR-WBCT correlation was substantial (κ 0.68). WBXR diagnostic accuracy to predict the WBCT results was 85%. CONCLUSIONS: The proposed method for medial column internal rotation measurement using WBXR is reliable and has a substantial agreement with WBCT measurements. LEVELS OF EVIDENCE: Level III.