Psychological Factors Affect Knee Arthroplasty Outcome

New findings suggest treatment effect may be greater if researchers control for response shift

THURSDAY, Dec. 7 (HealthDay News) -- Knee arthroplasty patients may perceive themselves as having been in worse condition before undergoing surgery than they actually were, according to a report in the December issue of the Journal of Bone & Joint Surgery, which suggests that response shift may play a role in outcome assessment among these patients.

Helen Razmjou, M.Sc., P.T., Ph.D., of the Sunnybrook Health Sciences Centre in Toronto, Canada, and colleagues examined whether response shift -- the psychological change in a person's perception of their quality of life following a change in health status -- was a factor in outcome assessment among 125 patients with knee osteoarthritis undergoing arthroplasty. Patients completed quality-of-life questionnaires before surgery and then six months afterward.

Patients believed their disability prior to surgery was worse than it really was and showed a response shift in pain, physical function and total Western Ontario and McMaster Universities Osteoarthritis score six months after surgery. The response shift did not affect the interpretation of clinical results, but it is an important part in determining the success or failure of a surgery as quantified with self-administered quality-of-life measures.

"The present study demonstrated that response shift occurs at six months in association with outcome assessments performed with the use of self-administered questionnaires for patients undergoing total knee replacement," the authors conclude.

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