Spondyloarthritis & psoriatic arthritis
Assessing cervical rotation in ankylosing spondylitis: iPhone Compass versus traditional tools
Authors' conclusion
Through the integration of everyday smartphone technology for clinical use, the iPhone Compass application can be considered a practical and accessible tool for measuring CR in patients with AS, offering potential benefits for clinical practice.
Study context
- Population
- Patients with ankylosing spondylitis (AS) receiving care at a rheumatology outpatient clinic73% male
- Participants
- 30 patients
- Comparison
- iPhone 4 Compass application vs inclinometer vs universal goniometer for measuring cervical rotation
- Outcome
- Reliability of the iPhone Compass application for measuring cervical rotation degrees vs inclinometer and universal goniometer
Methodological detailsintrarater and interrater reliability (intraclass correlation coefficients (ICCs)), Bland-Altman agreement analysis, each measurement performed twice by two examiners
- Intrarater and interrater reliability (ICCs)
- Bland-Altman agreement analysis
- Each measurement performed twice by two examiners
Main finding
As reported in the abstract
Intrarater and interrater reliability (ICCs)
- Excellent intrarater and interrater reliability across all three measurement methods in the entire sample
Further findings
| Outcome | Estimate | |
|---|---|---|
| Agreement (Bland-Altman), iPhone vs inclinometer, mean difference (bias)iPhonevs InclinometerExaminer 1 · good agreement | mean difference (bias) −5.6 (95% CI −7.6 to −3.6) | |
| Agreement (Bland-Altman), iPhone vs inclinometer, mean difference (bias)iPhonevs InclinometerExaminer 2 · good agreement | mean difference (bias) −6.3 (95% CI −8.8 to −3.8) | |
| Agreement (Bland-Altman), iPhonevs universal goniometer, mean differenceBetween iPhone and Universal goniometer · Examiner 1 | mean difference 2.3 (95% CI −0.4 to 5.2) | |
| Agreement (Bland-Altman), universal goniometer vs inclinometer, mean differenceUniversal goniometervs InclinometerExaminer 1 | mean difference −8.0 (95% CI −11.2 to −4.8) | |
| −15−10−50510Difference (linear scale) |
| Outcome | Mean difference |
|---|---|
| Agreement (Bland-Altman), iPhone vs universal goniometer, mean differenceBetween iPhone and Universal goniometer · Examiner 2 | 4.1 |
| Agreement (Bland-Altman), universal goniometer vs inclinometer, mean differenceUniversal goniometer vs Inclinometer · Examiner 2 | −10.4 |
Original publication
Assessing cervical rotation in ankylosing spondylitis: iPhone Compass versus traditional tools. Scand J Rheumatol. Published 10 November 2025. doi:10.
Composed by AI from the published abstract and checked against it. How Briefs are made →