Hip-specific quality of life survey for patients with hip osteoarthritis - development and preliminary validity assessment.

BACKGROUND: Many various surveys are used to assess quality of life of patients with hip osteoarthritis, but none of them evaluates quality of life dependent on a single joint in bilateral disease. Aim. Development and preliminary validation of hip-specific quality of life survey (HSS) of patients with hip osteoarthritis. MATERIAL AND METHODS: A group of experts developed the final version of HSS questionnaire in 4 stages. Statistical analysis was conducted on 181 preoperative and postoperative HSS questionnaires completed by patients undergoing hip replacement surgery due to hip osteoarthritis. Discrimination index for each item, questionnaire internal consistency, proportion and dispersion of unanswered items, questionnaire filling time, ceiling effect and floor effect values as well as correlation between each item and subscale score were subject to statistical analysis. RESULTS: Final version of the questionnaire is characterized by good discriminant power (CR >3 for each item except for one). Cronbach alpha coefficient for each subscale of preoperative as well as postoperative questionnaire reached a value over 0.8 and point value for each item correlated significantly with the sum of points in each HSS subscale. CONCLUSIONS: No floor effect was observed in any of the cases, while ceiling effect was demonstrated in 1.1% of preoperative HSS questionnaires.