Convergent construct validity of the Brazilian version of the Houghton scale

Abstract

Background: After lower limb amputations, a decrease in gait capacity, even with prostheses, is common and persistent. Functional ability involves multiple constructs; therefore, several outcome measures, such as performance tests or self-report questionnaires, should be used to evaluate people with amputation who use prostheses. Objective: To analyze the convergent construct validity of the Brazilian version of the Houghton scale in a sample of lower limb prosthesis users. Methods: Volunteers selected were older than 18 years with any level of lower limb amputation and prosthesis use for at least 6 months. In this study, evidence of construct validity of the Houghton scale was established by the Spearman rho correlation with the Brazilian translation of the Prosthetic Limb Users Survey of Mobility and with the Physical Function (PF) and Emotional Well-being subdomains of the Medical Outcomes Study 36-Short Form Health Survey. Results: Seventy-one volunteers were recruited for the study. The sample consisted mainly of men (70.4%) with a mean age of 50 ± 12 years. The primary cause of amputation was traumatic (53.5%), and most participants (54.9%) had a transtibial amputation. The Houghton questionnaire correlated strongly with the Brazilian translation of the Prosthetic Limb Users Survey of Mobility questionnaire (rho: 0.74, p < 0.01) and weakly with the PF and Emotional Well-being of the 36-Short Form Health Survey (rho: 0.06 and rho: 0.22, respectively, p > 0.05). Conclusion: This study showed evidence of convergent construct validity of the Houghton questionnaire to measure and classify functional use of lower limb prostheses, with great value to clinical practice. Additional work is needed to assess other measurement properties in different samples.