Interpretations of the clinical outcomes of the nonresponders to mail surveys in patients after total knee arthroplasty.

This study examined whether or not nonresponders to mail survey have poorer clinical outcomes than responders. A postal questionnaire, which was designed to evaluate the functional disability and patient's satisfaction, was mailed to 387 patients whose 1-year clinical outcomes were available. Of the 270 patients (69.8%) who responded, 247 (91.4%) reported that they were satisfied with their replaced knees. The knees of the nonresponders showed significantly poorer results in terms of the function-related scales (American Knee Society score function, Western Ontario McMaster University Osteoarthritis Index scale function, Short-Form 36 physical and functional scores) than the knees of the responders, whereas there were no significant differences in the pain-related scales. The clinical results of the nonresponders were poorer in most of the clinical outcome scales than those of the satisfied subgroup of responders but better than those of the dissatisfied subgroup. The results of the pain-related scales were similar to the satisfied subgroup but the function-related scales were similar to the dissatisfied subgroup. 2010 Elsevier Inc. All rights reserved.