Associations between terminal device shape and prosthesis weight and key outcomes differ for body-powered and myoelectric prosthesis users: An observational study.

BACKGROUND

Anthropomorphic terminal device shape (shape) and prosthesis weight may affect key patient-centered outcomes. No studies have quantified these relationships or examined whether shape and weight affect body-powered and myoelectric prosthesis users differentially.

OBJECTIVE

Explore the associations between prosthesis weight, shape, and a variety of outcomes.

STUDY

DESIGN

Multisite observational study of 232 individuals with transradial and transhumeral amputation using upper limb prosthetic devices.

METHODS

Shape was classified as anthropomorphic (yes/no). Prosthesis weight was categorized as light (<1 kg), moderate (1-1.6 kg), and heavy (1.6+ kg). Primary outcomes included prosthesis satisfaction, hours of prosthesis use/day, self-reported disability, and health-related quality of life. Data were stratified by prosthesis type (body-powered (BP) and myoelectric) and bivariate comparisons examined outcomes by weight and shape. Separate multivariable linear and logistic regressions examined associations between shape and weight and outcomes, controlling for potential confounders.

RESULTS

In BP users, after controlling for amputation level and other factors, heavy prostheses was associated with a 0.5 point decrease in TAPES satisfaction scores and greater odds of back (OR 25.7), neck (OR 6.4), residual limb (OR 4.2), and contralateral limb pain (OR 8.3) as compared with light prostheses. Anthropomorphic shape was associated with a 1.0 point decrease in TAPES satisfaction. In myoelectric device users, heavier weight was associated with greater odds of back pain (OR 9.9).

CONCLUSIONS

Heavier prostheses are associated with negative outcomes and affect BP and myoelectric users differentially. Efforts to decrease prosthesis weight may improve satisfaction and decrease prevalence of painful conditions, particularly in body-powered prosthesis users.