Questionnaire for Persons with a Transfemoral Amputation (Q-TFA): initial validity and reliability of a new outcome measure.

The Questionnaire for Persons with a Transfemoral Amputation (Q-TFA) is a new self-report measure developed for nonelderly transfemoral amputees using a socket- or osseointegrated prosthesis to reflect use, mobility, problems, and global health, each in a separate score (0-100). This paper describes the initial measurement properties of the Q-TFA as completed by 156 persons with a transfemoral amputation using a socket prosthesis (67% male, 92% nonvascular cases, mean age 51 years). Criterion validity was determined by associations between scores of the Q-TFA and the Short-Form 36 (SF-36)-Item Health Survey. Reliability was assessed by retest (n = 48) and by determination of the internal consistency. Correlations between Q-TFA and SF-36-Item Health Survey scales matched hypothesized patterns. Intraclass correlations were between 0.89 and 0.97, and measurement error ranged from 10 to 19 points. Cronbach's alpha revealed good internal consistency, with no values less than 0.7. This study shows that the Q-TFA, applied to persons using a transfemoral socket prosthesis, has adequate initial validity and reliability.