RELIABILITY AND STANDARDIZATION OF THE HIP EXAMINATION IN OSTEOARTHRITIS

Abstract

Purpose: To evaluate the benefits of standardization on the reliability of the physical examination of the hip by rheumatologists and orthopaedic surgeons

Methods: Six subjects with mild to severe hip osteoarthritis (OA) were examined by 6 examiners (4 rheumatologists, 2 orthopedic surgeons) experienced in the assessment of hip OA using a 6x6 Latin square design. Subjects were examined, followed by a standardization meeting and, a day later, by post-standardization examinations. 33 hip examination maneuvers were evaluated, including range of motion, pain, tenderness, muscle strength, leg length and gait. The order of examinations was randomized for each examiner. For dichotomous signs, agreement was calculated as the prevalence-adjusted bias-adjusted kappa (PABAK). Ordinal and continuous variables were analyzed by ANOVA, using the proportion of variance due to rheumatologists to calculate a reliability coefficient (Rc).

Results: Subjects’ mean age was 61 years (range 49–65), mean BMI was 24 (range 21–30), mean WOMAC pain on walking was 52 mm (range 21–81mm). 23/33 (70%) hip examinations were reliable after standardization. Two new items resulted from the standardization meeting. Pre-/post-standardization reliability for select hip examinations using PABAK were as follows: Gait 0.06/0.52; pain on internal rotation 0.60/0.52; pain on external rotation 0.24/0.72; pain on flexion 0.46/0.82; Patrick test for hip pain 0.78/0.80; Thomas test 0.60/0.88; Trendelenburg test 0.36/0.06. Pre-/post-standardization reliability for select hip examinations using Rc were as follows: hip flexion strength 0.83/0.95; hip abduction strength 0.90/0.86; hip adduction strength 0.87/0.86; ROM internal rotation (supine) 0.87/0.94; ROM external rotation (supine) 0.87/0.80.

Conclusions: Moderate to very good agreement was present for many hip examinations prior to standardization. Improved reliability was achieved after standardization for many but not all hip assessments. This will be important for improved outcome studies of early hip OA.