3D topographic acquisitions to predict spinal curvature in adolescent idiopathic scoliosis: a prospective validation study

Aims: This study aims to determine the reliability, accuracy, and usability of a new health application that uses AI to estimate major coronal curve magnitude in patients with adolescent idiopathic scoliosis (AIS) from 3D surface topography (ST) captured on a smartphone video scan. Methods: This is a prospective validation study. AIS patients, aged ten to 18 years, with coronal curve magnitudes ≤ 45° were recruited at a tertiary care spine clinic. A single trained researcher performed scans twice, six months apart, during participants’ routine clinical and radiological assessment. Participants were asked to complete a scan once a month between clinic visits, starting the day of recruitment. Agreement was calculated by comparing scan curve magnitude predictions to the reference standard: a three-foot standing spine radiograph measured by blinded spine clinicians. Inter-rater reliability was assessed by comparing in-clinic to home scan predictions. Measures of diagnostic accuracy to determine the app’s ability to screen for coronal deformity > 25° and its ability to detect progression > 5° over a six-month period were determined. Successful compared with failed scans were recorded. Results: Among participants (n = 63), 59 patients (94%) had at least one successful in-clinic scan and 32 patients (51%) had at least one successful home scan. Agreement with the reference standard was moderate for in-clinic scans (intraclass correlation coefficient (ICC) 0.535) and poor for home scans (ICC 0.402). Inter-rater reliability between in-clinic and home scans was poor (ICC 0.168). The app had an accuracy of 70% when discriminating between curve magnitudes ± 25° and detecting curve progression > 5°. A larger proportion of scans failed at-home (30%) compared with in-clinic (16%). Conclusion: Conceptually, the app shows potential as an accessible screening tool for scoliosis. However, the accuracy and reliability suggest it is not yet a reasonable replacement for radiographs and in-person clinical evaluation. Cite this article: Bone Jt Open 2026;7(4):473–481.