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

Osteoarthritis Cartilage. 2010 Mar;18(3):365-71. doi: 10.1016/j.joca.2009.10.001. Epub 2009 Oct 8.


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 degrees, lower legs hanging unsupported and a standardized load of 5 kg applied to both ankles using a bilateral pulley system. Clinical assessment of IR was performed in supine position with hips and knees flexed 90 degrees 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 <or=0.001). The average range of motion (ROM) obtained with examination chair and clinical assessment were similar (difference 1.1 degrees, 95% CI - 0.7-2.8 degrees, 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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Biomechanical Phenomena
  • Equipment Design
  • Equipment and Supplies
  • Hip / anatomy & histology*
  • Hip Joint / physiology*
  • Humans
  • Male
  • Osteoarthritis, Hip / physiopathology*
  • Range of Motion, Articular*
  • Reference Values
  • Rotation
  • Switzerland
  • Young Adult