COPYRIGHT © 2002 BY THE JOURNAL OF BONE AND JOINT SURGERY, INCORPORATED Comparison of Patient and Doctor Responses to a

Background: Surgeons traditionally undertake a prospective evaluation of patients undergoing total hip arthro-plasty in order to determine outcomes. The validity of doctor-derived data is questionable because of the poten-tial for interobserver error, reporting bias, and differences between the perceptions of doctors and patients. Also, the use of doctor-derived data necessitates the use of costly outpatient services. Consequently, there are likely to be benefits associated with the use of patient-derived clinical evaluation data. However, few studies have focused on whether data obtained from the patient and doctor differ. Methods: The agreement between patient and doctor responses on a sixteen-item total hip arthroplasty clinical evaluation questionnaire completed at more than 2900 clinical assessments was determined. Data from re-peated assessments performed preoperatively and postoperatively enabled stratified analyses that were used to examine reasons for disagreement and factors influencing agreement. Agreement was measured with use of the kappa coefficient. Results: For twelve of the sixteen items, the patient responses had acceptable agreement with the doctor re-sponses. Some important differences between patient-derived and doctor-derived data were found. If the pa-tient had other joint or health problems, had a revision total hip arthroplasty, or reported mild or moderate pain, there was a greater chance of reduced agreement on the pain items. Younger patients demonstrated bette