To The Editor:
I read with interest the article "Patients Can Provide a Valid Assessment of Quality of Life, Functional Status, and General Health on the Day They Undergo Knee Surgery" (2008;90:264-70), by Bryant et al. As a psychologist, it seems likely to me that the demand characteristics of the situation on the day of surgery would overwhelm a patient's judgment about quality of life, functional status, and general health. Demand characteristics include concern about the surgeon's opinion, wanting to please the surgeon, and wanting to be seen as a "good" patient. Factors like these have been demonstrated to influence responses and were first reported by Rosenthal as early as 19761.
Additionally, I agree with the Commentary and Perspective by Elizabeth A. Lingard2. There is wide variance in the degree of anxiety experienced by patients on the occasion of surgery. These differences should be measured and reported for the sake of accuracy. The use of partial tests affects the validity of these measures and cannot be considered reliable.
Furthermore, a patient's perception of arthroscopy and arthroplasty are not comparable. Arthroplasty is substantially more invasive than arthroscopy and patients understand the difference, so the results, even if valid, cannot be generalized to patients having an arthroplasty.
Finally, there are substantial problems with the patient-reporting measures; the addition of same-day surgery assessment makes accurate outcome very unlikely.