Purpose of Review
To assess validity of instruments used in adult lower limb amputees, whether patient characteristics can predict relative effectiveness of different lower limb prosthesis (LLP) components, and long-term LLP use.
- Thirty of 50 evaluated instruments (ambulatory/functional outcomes and other measures) have evidence of validity and reliability. Many studies use nonvalidated instruments.
- Based on a small number of studies, patient characteristics do not predict who would most benefit from a given LLP component. Half of studies used nonvalidated instruments and analyses were inadequate.
- Only a few studies assessed long-term LLP use; 11 to 22 percent of patients abandon their LLP after 1 year; people with above-the-knee amputations are more likely toabandon their prostheses than people with below-the-knee amputations; 24 to 29 percent of people with LLPs use them only indoors 1 year after they first receive the prostheses. The studies, though, had important methodological issues.
Background. Lower limb prosthesis (LLP) candidates are a heterogeneous group. Many LLP options exist. How to best match an amputee with an LLP is unclear. Optimal selection of devices should be guided by evidence on which amputees would do best with which LLP component or configuration, and which evaluation instruments are valid and reliable in this population.
Methods. We addressed questions pertaining to: assessing validity, reliability, and related psychometric properties for assessment techniques, predictor tools, and outcome measures in lower limb amputees; determining which patient and other characteristics may predict which LLP configuration or component would result in better clinical and patient-centered outcomes for different lower limb amputees (i.e., heterogeneity of treatment effect); determining whether patient expectations align with outcomes; evaluating whether patients are satisfied with the process of obtaining their LLPs; and describing long-term use of LLPs. The review does not evaluate overall comparative effectiveness among LLP components, nor does it include assessment of biomechanical outcomes. We searched six databases and other sources through October 2017 for eligible studies.
Results. We found eligible studies that assessed the psychometric properties of 50 instruments (classified as assessment techniques, prediction tools, and outcome measures). Of these, 30 have evidence for both validity and reliability, but only 17 of these 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. Of 13 studies reporting data or analyses to allow assessment of heterogeneity of treatment effect, 7 used both predictor and outcome measures with evidence of validity. These studies mostly included younger men with unilateral transfemoral amputations due to trauma. Overall, studies did not identify participant characteristics that predict which lower limb amputees would benefit most or least from a given component (low strength of evidence); the studies were almost all underpowered to address this Key Question. Two studies provide low strength of evidence that people are satisfied with their encounters with their prosthetists. No eligible study addressed how study participants' preprescription expectations of ambulation align with outcomes. Based on eight eligible studies, there is low strength of evidence that (1) about 11 to 22 percent of lower limb amputees who receive an LLP prescription stop using the prosthesis at about 1 year and (2) people with unilateral transfemoral amputations are about twice as likely to abandon their LLP than those with transtibial amputations. There is low strength of evidence that 24 to 29 percent of LLP recipients use their prostheses only indoors at 1 year.
Conclusions. Numerous instruments assessing ambulation, function, quality of life, and other patient-centered outcomes have evidence of validity and reliability for people with lower limb amputations. The literature does not provide adequate evidence regarding whether specific characteristics or preprescription instruments are predictive of which specific LLP component individuals should receive to maximize ambulation, function, and quality of life, or to minimize abandonment or limited use. Further high-quality research in representative samples of people with LLPs is needed to inform optimal matching of prosthetic components to patients and to assess patient expectations and satisfaction with care.
Balk EM, Gazula A, Markozannes G, et al. Psychometric Properties of Functional, Ambulatory, and Quality of Life Instruments in Lower Limb Amputees: A Systematic Review. Arch Phys Med Rehabil. 2019 Dec;100(12);2354-2370. doi: 10.1016/j.apmr.2019.02.015. Epub 2019 Apr 12.
Suggested citation: Balk EM, Gazula A, Markozannes G, Kimmel HJ, Saldanha IJ, Resnik LJ, Trikalinos TA. Lower Limb Prostheses: Measurement Instruments, Comparison of Component Effects by Subgroups, and Long-Term Outcomes. Comparative Effectiveness Review No. 213. (Prepared by the Brown Evidence-based Practice Center under Contract No. 290-2015-00002-I.) AHRQ Publication No.18-EHC017-EF. Rockville, MD: Agency for Healthcare Research and Quality; September 2018. Posted final reports are located on the Effective Health Care Program search page. DOI: 10.23970/AHRQEPCCER213.