Background: The Nottingham Adjustment Scale-Japanese version (hereinafter referred to as NAS-J) was developed to measure psychological adaptation to visually impairment. Several disease-specific modified versions have been developed in Japan. The purpose of this study was to develop and test the reliability, validity, and responsiveness of the NAS-J for hip osteoarthritis patients.
Methods: Patients with osteoarthritis of the hip managed as outpatients at the Department of Orthopaedic Surgery of one university hospital gave informed written consent to be enrolled in this study. Subjects were asked to complete a questionnaire consisting of the NAS-J--Hip edition (hereinafter referred to as NAS-J-HIP), health-related QOL (Short Form 36). Subjects' medical and treatment histories, and the Japanese Hip Society's Evaluation Chart of Hip Joint Functions (hereinafter referred to as the JOA score) were also collected from their medical records. Psychometric analyses were conducted to test reliability, validity, and responsiveness.
Results: A total of 231 patients agreed to participate in the survey, and responses were obtained from 168 (72.7%). Their mean +/- SD age was 52.5 +/- 12.4 years, and the mean JOA score was 80.9 points. By factor analysis using the principal factor method, seven factors were extracted: (1) anxiety/depression, (2) self-esteem, (3) attitude, (4) locus of control, (5) acceptance, (6) self-efficacy, and (7) attributional style. Concurrent validity was the result according to the near hypothesis. Cronbach's alpha-coefficient ranged from 0.68 to 0.83, indicating high internal consistency.
Conclusions: For hip osteoarthritis patients, construct validity was confirmed for NAS-J-HIP. Furthermore, seven factors comprising 27 items with high internal consistency were incorporated into NAS-J-HIP. This scale can be used to assess the psychological adaptation of hip osteoarthritis patients.