Page 105 - The value of total hip and knee arthroplasties for patients

Patients’ pre-operative general and specific outcome expectations predict postoperative pain and function after total knee and total hip arthroplasties
the CEQ expectancy score.The R2 values of the final models were then compared to assess the differences between predictive ability of the models with generic CEQ expectancy subscale and the models with the more specific HSS expectation survey score. All analyses were performed with IBM SPSS Statistics 20 and were done separately for TKA and THA.
Results
Flow of patients and characteristics of the sample.
Between July 2011 to September 2012 189 THA and 186 TKA patients were
enrolled in the study and completed the additional questions on outcome
expectations. In the current study the patients from this subgroup that returned the
follow-up questionnaires (146 TKA patients and 148 THA patients) are included.
TKA patients included in this study had a mean age of 66.9 years (SD 9.2) and 69% 6 was female,THA patients included in this study had a mean age 67.2 (SD 9.5) and
57% was female. Both the characteristics of the total sample and the subsample included in the current analyses are described in Table 1. The characteristics (age, gender, baseline HOOS and KOOS scores) of the subsample of patients included in current analyses did not differ from those of the total study sample.
The predictive value of outcome expectations for Total Knee Arthroplasty
Multivariate linear regression models identified BMI, better mental health (SF-36 mental component summary) baseline function (baseline KOOS ADL subscale) and patients’ general expectations of outcome (CEQ expectancy) as significant predictors of a better (function) KOOS ADL score 12 months post TKA (Table 2). Higher (more positive) scores on the expectation measures predicted more favorable outcomes.The final model explained 30.3% (R2 0.303) of the variance in outcome.When the CEQ expectancy score was replaced by the more specific expectations measure HSS expectation function subscale the explained variance decreased to 25.2% (R2 0.252).
For the outcome pain 12 months after TKA, BMI, mental health and patients’ general expectations of outcome (CEQ expectancy) were identified as significant predictors (table 3).The final model explained 17% (R2 0.170) of the variance of the postoperative pain. When the CEQ expectancy score was replaced by the more specific HSS expectation pain subscale the variance explained slightly improved to 17.7% (R2 0.177).
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