Reliability of the hip examination in osteoarthritis: Effect of standardization

Abstract

To assess the reliability of the physical examination of the hip in osteoarthritis (OA) among rheumatologists and orthopedic surgeons, and to evaluate the benefits of standardization. Thirty-five physical signs and techniques were evaluated using a 6 x 6 Latin square design. Subjects with mild to severe hip OA, based on physical and radiographic signs, were examined in random order prior to and following standardization of physical examination techniques. For dichotomous signs, agreement was calculated as the prevalence-adjusted bias-adjusted kappa (PABAK), whereas for continuous and ordinal signs a reliability coefficient was calculated using analysis of variance. A PABAK >0.60 and a reliability coefficient >0.80 were considered to indicate adequate reliability. Adequate post-standardization reliability was achieved for 25 (71%) of 35 signs. The most highly reliable signs included true and apparent leg length discrepancy > or =1.5 cm; hip flexion, abduction, adduction, and extension strength; log roll test for hip pain; internal rotation and flexion range of motion; and Thomas test for flexion contracture. The standardization process was associated with substantial improvements in reliability for a number of physical signs, although minimal or no change was noted for some. Only 1 sign, Trendelenburg's sign, was highly unreliable post-standardization. With the exception of gait, a comprehensive hip examination can be performed with adequate reliability. Post-standardization reliability is improved compared with pre-standardization reliability for some physical signs. The application of these findings to future OA studies will contribute to improved outcome assessments in OA.