Evaluating quality of life in hip and knee replacement: Psychometric properties of the World Health Organization Quality of Life short version instrument

OBJECTIVE: To evaluate the psychometric properties of the World Health Organization Quality of Life short version instrument (WHOQOL-BREF), and to determine its responsiveness in assessing early outcome after total hip or knee replacement surgery. METHODS: At baseline (entry to an orthopedic waiting list), 279 participants completed the WHOQOL-BREF instrument, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Assessment of Quality of Life (AQOL) instrument, Kessler Psychological Distress (K10) scale, and the modified Health Assessment Questionnaire (MHAQ). A total of 74 patients completed reassessments 3 months after surgery. RESULTS: The WHOQOL-BREF demonstrated acceptable internal consistency for all domains (Cronbach's alpha = 0.76-0.84) and moderate concurrent validity for the physical and psychological domains (r = 0.67 for physical versus AQOL; r = -0.71 for psychological versus K10). Minimal ceiling or floor effects were identified at baseline or 3 months, except for the social relationships domain. The disease-specific WOMAC subscales were most responsive to change (relative efficiency RE] 0.66-1.00). Apart from social relationships, all WHOQOL-BREF scores improved significantly after surgery. The physical domain was more responsive than the AQOL (RE 0.50 versus 0.42) and was similar to the MHAQ (RE 0.55 for MHAQ). The responsiveness of the psychological domain was similar to that of the K10 scale (RE 0.11 versus 0.08). CONCLUSION: The WHOQOL-BREF has good psychometric properties for use in persons with severe joint disease, and by providing complementary information, it offers clinicians and researchers an additional tool for comprehensively assessing quality of life in this patient group.