Reliability and concurrent validity of smartphone-based inclinometer applications for sagittal spinal curvature assessment
European Spine Journal, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Basım Tarihi: 2026
- Doi Numarası: 10.1007/s00586-026-10483-5
- Dergi Adı: European Spine Journal
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, CINAHL, EMBASE, MEDLINE, Academic Search Ultimate (EBSCO), Biomedical Reference Collection: Corporate Edition (EBSCO), Health Research Premium Collection (ProQuest), Pharma Collection (ProQuest)
- Anahtar Kelimeler: Agreement, Concurrent validity, Inclinometer, Reliability, Sagittal spinal alignment, Smartphone
- Ankara Hacı Bayram Veli Üniversitesi Adresli: Hayır
Özet
Purpose: To evaluate the same-day intra-rater reliability, 24–48-hour test–retest reliability, concurrent validity, and inter-device agreement of sagittal spinal alignment measurements obtained using iOS- and Android-based smartphone inclinometer applications and a conventional bubble inclinometer. Methods: Sixty-three healthy young adults (32 males, 31 females; mean age, 20.3 ± 1.2 years) were assessed at five spinal regions using the three measurement methods. Measurements were repeated within the same session and 24–48 h later. Reliability was evaluated using intraclass correlation coefficients (ICC), standard error of measurement, and minimum detectable change (MDC). Concurrent validity and inter-device agreement were assessed using ICC(2,1), Pearson’s correlation, Lin’s concordance correlation coefficient (CCC), and Bland–Altman analysis. Results: Same-day ICC values ranged from 0.758 to 0.884 for iOS, 0.541–0.921 for Android, and 0.727–0.871 for the bubble inclinometer. Test–retest reliability was lower, ranging from 0.469 to 0.702, 0.097–0.607, and 0.392–0.745, respectively. The lowest ICC occurred for Android at the sacrum (0.097). MDC₉₀ ranged from 7.11° to 14.46°, and CCC values from 0.512 to 0.888. Bland–Altman analysis showed systematic bias in several device–landmark comparisons, with the largest absolute bias at C7 for iOS versus bubble inclinometry (− 5.08°). Conclusion: Measurement performance varied by device, anatomical landmark, and assessment interval. Same-day repeatability was higher than 24–48-hour test–retest reliability, and the MDC values indicate that small longitudinal changes should be interpreted cautiously. Smartphone-based inclinometry may be useful for same-session assessment, but the observed inter-device bias does not support routine interchangeability. Serial measurements should preferably use the same device, application, landmarks, and standardized protocol.