Psychometric Properties of Functional, Ambulatory, and Quality of Life Instruments in Lower Limb Amputees: A Systematic Review

Abstract

Objective: Summarize the psychometric properties of functional, ambulatory, and quality of life instruments among adult lower limb amputees, highlighting evidence deemed generalizable to the United States Medicare population.

Data sources: Six databases and existing systematic reviews through October 30, 2017. Searches included terms for lower limb amputation or prostheses and outcome measures in humans, without language restriction.

Study selection: We included peer-reviewed studies of at least 20 adults (≥18 years) with lower limb amputation. Eligible studies reported on psychometric properties of functional, ambulatory, or quality of life instruments. Fifty-three of 425 retrieved articles (12%) met criteria.

Data extraction: Study characteristics and psychometric property data (validity, reliability, responsiveness, minimum detectable change, minimal important difference, or floor or ceiling effect) were extracted into a customized form based on standardized criteria. All extracted data were confirmed by 2 experts in systematic review and rehabilitation outcome measurement. Instruments were categorized regarding having been validated and found reliable. Other reported psychometric properties were recorded. Studies were also assessed for applicability to the Medicare population based on age and amputation etiology (dysvascular).

Data synthesis: Fifty-six studies (in 53 articles) reported psychometric properties of 50 instruments. There is evidence for both validity and reliability for 30 instruments, 17 of which have evidence that was deemed generalizable to the Medicare population. Most of the remaining instruments have evidence of either validity or reliability, but not both. Twelve instruments have been assessed specifically among lower limb amputees prior to prosthesis prescription. Thirteen instruments have been assessed regarding their predictive properties for future outcomes.

Conclusions: Numerous instruments assessing ambulation, function, quality of life, and other patient-centered outcomes have evidence of validity and reliability for adults with lower limb amputations. Researchers and clinicians should use validated, reliable instruments when feasible. Many existing and new instruments require validation for use with lower limb amputees.

Keywords: Amputation; Artificial limbs; Disability evaluation; Lower extremity; Psychometrics; Rehabilitation; Reproducibility of results; Systematic review; Validation studies.