Automatic Weight-Bearing Foot Series Measurements Using Deep Learning

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Background: Foot deformities, particularly hallux valgus, significantly impact patients’ quality of life. Conventional radiographs are essential for their assessment, but manual measurements are time-consuming and variable. This study assessed the reliability of a deep learning-based solution (Milvue, France) that automates podiatry angle measurements from radiographs compared to manual measurements made by radiologists. Methods: A retrospective, non-interventional study at Perpignan Hospital analyzed the weight-bearing foot radiographs of 105 adult patients (August 2017–August 2022). The deep learning (DL) model’s measurements were compared to those of two radiologists for various angles (M1-P1, M1-M2, M1-M5, and P1-P2 for Djian–Annonier, calcaneal slope, first metatarsal slope, and Meary–Tomeno angles). Statistical analyses evaluated DL performance and inter-observer variability. Results: Of the 105 patients included (29 men and 76 women; mean age 55), the DL solution showed excellent consistency with manual measurements, except for the P1-P2 angle. The mean absolute error (MAE) for the frontal view was lowest for M1-M2 (0.96°) and highest for P1-P2 (3.16°). Intraclass correlation coefficients (ICCs) indicated excellent agreement for M1-P1, M1-M2, and M1-M5. For the lateral view, the MAE was 0.92° for calcaneal pitch and 2.83° for Meary–Tomeno, with ICCs ≥ 0.93. For hallux valgus detection, accuracy was 94%, sensitivity was 91.1%, and specificity was 97.2%. Manual measurements averaged 203 s per patient, while DL processing was nearly instantaneous. Conclusions: The DL solution reliably automates foot alignment assessments, significantly reducing time without compromising accuracy. It may improve clinical efficiency and consistency in podiatric evaluations.