New study design evaluated the validity of measures to assess change after hip or knee arthroplasty

Paul W. Stratford, Deborah M. Kennedy and Daniel L. Riddle

This article proposes a study design to evaluate the ability of measures to assess physical function relatively independent of pain for total hip (THA) or knee (TKA) arthroplasty.  A repeated-measure study design was developed and applied to patients undergoing THA or TKA. A performance battery (PB) (walking, stair, and timed-up-and-go) was used as the gold standard measure for “physical function.” Recent evidence indicates physical performance deteriorates 1 month after surgery compared to presurgical measures and patients with THA deteriorate to a greater extent than patients with TKA. Our design assessed whether the results from self-report measures (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC] and the Lower Extremity Functional Scale [LEFS]) of physical function were consistent with changes found using the PB.

Our findings support the proposed design in that the PB was more sensitive to change than the self-report measures.

Journal of Clinical Epidemiology, 2009, 62(3), 347-352

Link to Abstract