While total joint replacement (TJR) is the most effective treatment for end-stage osteoarthritis (OA), one-third of patients do not experience clinically important improvement in pain or function following the surgery. Thus, it is important to identify factors for nonresponders and develop strategies to improve TJR outcomes.
Study participants were patients who underwent TJR (hip/knee) due to OA and completed the WOMAC before and on average 4 years after surgery. Nonresponders (pain nonresponders, function nonresponders, pain and function nonresponders) were determined using the WOMAC change score from baseline to follow-up under two previously reported criteria. Eighty-eight self-reported factors collected by a general health questionnaire were examined for associations with nonresponders.
A total of 601 patients (30.8% hip and 69.2% knee replacement) were included; 18% of them were found to be either pain or function nonresponders. Nine factors were identified in the univariable analyses to be associated with nonresponders, and 5 of them (clinical depression, multisite musculoskeletal pain [MSMP], younger age, golfer's elbow, and driving more than 4 hours on average per working day) remained significant in the multivariable analyses in at least one of six categories. Clinical depression, having MSMP, and younger age were the major factors to be independently associated with nonresponders across five categories. In addition, two factors (age at menopause and age at hysterectomy) were significantly associated with female nonresponders.
Our data suggested potential roles of pain perception, widespread pain sensitization, patient expectations, and early menopause in females in TJR outcomes, warranting further investigation.