Objective: Little has been reported on changes in health status in patients with osteoarthritis (OA) while waiting for hip or knee replacement surgery. In this study we assessed (1) changes in self-reported pain, stiffness and physical function in patients with OA of the hip or knee, from the decision to undergo surgery to 14 days prior to surgery, and (2) the determinants of these changes.
Methods: Among 353 baseline respondents, 170 waited >30 days for surgery, completed the Western Ontario and McMaster Universities Arthritis Index (WOMAC) before surgery and were included in the analysis of changes; 120 with OA of the hip and 50 of the knee. We analyzed changes in WOMAC scores using the paired t test and determinants of the changes using multiple linear regression.
Results: Patients with OA of the hip did not change on any WOMAC scale before surgery. Knee patients deteriorated with time on the WOMAC stiffness and total scales, but not on the pain or physical function subscales. In both patient categories, higher baseline WOMAC scores were associated with smaller changes on all subscales and the total score, and female sex was associated with deterioration on the pain subscale.
Conclusions: Patients with OA of the hip reported no change in pain, stiffness or physical function while waiting for joint replacement surgery, whereas patients with OA of the knee deteriorated on the stiffness and total scales of the WOMAC. This suggests a difference in patient selection, referral pattern or disease development between the patient categories.