Anatomical landmark position - Can we trust what we see? Results from an online reliability and validity study of osteopaths

摘要

Background: Practitioners traditionally use observation to classify the position of patients' anatomical landmarks. This information may contribute to diagnosis and patient management. Objectives: To calculate a) Inter-rater reliability of categorising the sagittal plane position of four anatomical landmarks (lateral femoral epicondyle, greater trochanter, mastoid process and acromion) on side-view photographs (with landmarks highlighted and not-highlighted) of anonymised subjects; b) Intra-rater reliability; c) Individual landmark inter-rater reliability; d) Validity against a 'gold standard' photograph. Design: Online inter- and intra-rater reliability study. Subjects: Photographed subjects: convenience sample of asymptomatic students; raters: randomly selected UK registered osteopaths. Methods: 40 photographs of 30 subjects were used, a priori clinically acceptable reliability was ≥0.4. Inter-rater arm: 20 photographs without landmark highlights plus 10 with highlights; Intra-rater arm: 10 duplicate photographs (non-highlighted landmarks). Validity arm: highlighted landmark scores versus 'gold standard' photographs with vertical line. Research ethics approval obtained. Raters: Osteopaths (n=48) categorised landmark position relative to imagined vertical-line Gwet's Agreement Coefficient 1 (AC1) calculated and chance-corrected coefficient benchmarked against Landis and Koch's scale Validity calculation used Kendall's tau-B. Results: Inter-rater reliability was 'fair' (AC1=0.342; 95% confidence interval (CI)=0.279-0.404) for non-highlighted landmarks and 'moderate' (AC1=0.700; 95% CI=0.596-0.805) for highlighted landmarks. Intra-rater reliability was 'fair' (AC1=0.522); range was 'poor' (AC1=0.160) to 'substantial' (AC1=0.896). No differences were found between individual landmarks. Validity was 'low' (TB=0.327; p=0.104). Conclusion: Both inter- and intra-rater reliability was 'fair' but below clinically acceptable levels, validity was 'low'. Together these results challenge the clinical practice of using observation to categorise anterio-posterior landmark position.