Willingness to go through surgery again validated the WOMAC clinically important difference from THR/TKR surgery.
OBJECTIVE
The objective was to determine the clinically important difference (CID) from primary total hip replacement (THR) and total knee replacement (TKR) surgeries using the Western Ontario McMaster University (WOMAC) osteoarthritis index.


METHODS
WOMAC scores were collected at decision for and 1 year after surgery (n=2,709). Transition ratings (15-point scale) were obtained at 1 year for pain and function, as well as a global assessment of willingness to go through surgery again. A "good deal better" defined the positive CID. WOMAC change scores for transition ratings and willingness to go through surgery again were evaluated using receiver operating characteristic curves. Patient characteristics within transition rating categories were examined.


RESULTS
For THR, the positive CIDs were 41 of 100 for pain and 34 of 100 for function. The negative CIDs were 35 and 33, respectively. For TKR, the positive CIDs were 36 for pain and 33 for function. The negative CIDs were 30 and 25, respectively. Change scores for willingness to go through surgery again validated CID values. Postoperative complications decreased the likelihood of a positive CID.


CONCLUSIONS
Improvement that is "a good deal better" is an appropriate threshold for the THR/TKR positive CID. Attaining a positive CID is negatively related to postoperative complications.
Chesworth
Bert M
BM
School of Physical Therapy, Faculty of Health Sciences, University of Western Ontario, Elborn College, 1201 Western Road, London, Ontario, Canada. bcheswor@uwo.ca
Mahomed
Nizar N
NN
Bourne
Robert B
RB
Davis
Aileen M
AM
D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000523:psychology / Q000534:rehabilitation*; D019645:Arthroplasty, Replacement, Knee / Q000523:psychology / Q000534:rehabilitation*; D005260:Female; D006304:Health Status; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D009864:Ontario / Q000453:epidemiology; D010003:Osteoarthritis / Q000453:epidemiology / Q000523:psychology / Q000534:rehabilitation*; D010147:Pain Measurement / Q000379:methods; D010149:Postoperative Pain / Q000523:psychology; D017060:Patient Satisfaction; D011336:Probability; D011788:Quality of Life / Q000523:psychology*; D012086:Reoperation / Q000523:psychology; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires