An examination chair to measure internal rotation of the hip in routine settings: a validation study

Reichenbach, S.; Jüni, P.; Nüesch, E.; Frey, F.; Ganz, R.; Leunig, M.

doi:10.1016/j.joca.2009.10.001

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Volume 18, Issue 3 , Pages 365-371, March 2010

An examination chair to measure internal rotation of the hip in routine settings: a validation study

S. Reichenbach
- Division of Clinical Epidemiology and Biostatistics, Institute of Social and Preventive Medicine (ISPM), University of Bern, Switzerland
- Department of Rheumatology, Clinical Immunology and Allergology, Inselspital, University of Bern, Switzerland
- CTU Bern, Inselspital, University of Bern, Switzerland
- Address correspondence and reprint requests to: Stephan Reichenbach, Institute of Social and Preventive Medicine, University of Bern, Finkenhubelweg 11, 3012 Bern, Switzerland. Tel: 41-31-631-35-29; Fax: 41-31-631-35-20.
- Both authors contributed equally to this work.
P. Jüni
- Division of Clinical Epidemiology and Biostatistics, Institute of Social and Preventive Medicine (ISPM), University of Bern, Switzerland
- CTU Bern, Inselspital, University of Bern, Switzerland
- Both authors contributed equally to this work.
E. Nüesch
- Division of Clinical Epidemiology and Biostatistics, Institute of Social and Preventive Medicine (ISPM), University of Bern, Switzerland
- CTU Bern, Inselspital, University of Bern, Switzerland
F. Frey
- Military Medical Branch, Armed Forces Logistics Organisation (AFLO), Switzerland
R. Ganz
- Department of Orthopaedic Surgery, University of Bern, Switzerland
M. Leunig
- Hip Service, Schulthess Clinic, Zürich, Switzerland and University of Bern, Switzerland

Received 11 June 2009; accepted 1 October 2009. published online 28 October 2009.

Summary

Objective

To determine the performance of a newly developed examination chair as compared with the clinical standard of assessing internal rotation (IR) of the flexed hip with a goniometer.

Methods

The examination chair allowed measurement of IR in a sitting position simultaneously in both hips, with hips and knees flexed 90°, lower legs hanging unsupported and a standardized load of 5kg applied to both ankles using a bilateral pulley system. Clinical assessment of IR was performed in supine position with hips and knees flexed 90° using a goniometer. Within the framework of a population-based inception cohort study, we calculated inter-observer agreement in two samples of 84 and 64 consecutive, unselected young asymptomatic males using intra-class correlation coefficients (ICC) and determined the correlation between IR assessed with examination chair and clinical assessment.

Results

Inter-observer agreement was excellent for the examination chair (ICC right hip, 0.92, 95% confidence interval [CI] 0.89–0.95; ICC left hip, 0.90, 95% CI 0.86–0.94), and considerably higher than that seen with clinical assessment (ICC right hip, 0.65, 95% CI 0.49–0.77; ICC left hip, 0.69, 95% CI 0.54–0.80, P for difference in ICC between examination chair and clinical assessment ≤0.001). The average range of motion (ROM) obtained with examination chair and clinical assessment were similar (difference 1.1°, 95% CI – 0.7–2.8°, P=0.23), and the correlation was strong (Pearson's coefficient, 0.75, 95% CI 0.62–0.84).

Conclusions

The use of the examination chair resulted in a precise assessment of hip IR in our population-based inception cohort study of young asymptomatic males. It was strongly correlated with standard clinical assessment of IR but was considerably more reliable.

Key words: Internal rotation, Hip, Examination, Chair, Femoroacetabular impingement, Validation