Economic benefits of microprocessor controlled prosthetic knees: a modeling study

Abstract

Background: Advanced prosthetic knees allow for more dynamic movements and improved quality of life, but payers have recently started questioning their value. To answer this question, the differential clinical outcomes and cost of microprocessor-controlled knees (MPK) compared to non-microprocessor controlled knees (NMPK) were assessed.

Methods: We conducted a literature review of the clinical and economic impacts of prosthetic knees, convened technical expert panel meetings, and implemented a simulation model over a 10-year time period for unilateral transfemoral Medicare amputees with a Medicare Functional Classification Level of 3 and 4 using estimates from the published literature and expert input. The results are summarized as an incremental cost effectiveness ratio (ICER) from a societal perspective, i.e., the incremental cost of MPK compared to NMPK for each quality-adjusted life-year gained. All costs were adjusted to 2016 U.S. dollars and discounted using a 3% rate to the present time.

Results: The results demonstrated that compared to NMPK over a 10-year time period: for every 100 persons, MPK results in 82 fewer major injurious falls, 62 fewer minor injurious falls, 16 fewer incidences of osteoarthritis, and 11 lives saved; on a per person per year basis, MPK reduces direct healthcare cost by $3676 and indirect cost by $909, but increases device acquisition and repair cost by $6287 and total cost by $1702; on a per person basis, MPK is associated with an incremental total cost of $10,604 and increases the number of life years by 0.11 and quality adjusted life years by 0.91. MPK has an ICER ratio of $11,606 per quality adjusted life year, and the economic benefits of MPK are robust in various sensitivity analyses.

Conclusions: Advanced prosthetics for transfemoral amputees, specifically MPKs, are associated with improved clinical benefits compared to non-MPKs. The economic benefits of MPKs are similar to or even greater than those of other medical technologies currently reimbursed by U.S. payers.

Keywords: Amputee; Economic analysis; Incremental cost effectiveness ratio; Microprocessor controlled knee; Transfemoral amputation.

Fig. 1

Injurious Falls and Fall-related Deaths Among MPK and NMPK Users, Note: MPK: microprocessor-controlled knees; NMPK: non-microprocessor controlled knees

Fig. 2

Quality of Life Among MPK and NMPK Users, Note: MPK: microprocessor-controlled knees; NMPK: non-microprocessor controlled knees. Source: [, , , –40]

Fig. 3

Savings Derived From the Use of MPK in Direct Healthcare Cost and Indirect Cost, Note: MPK: microprocessor-controlled knees; NMPK: non-microprocessor controlled knees. Results are reported on a per person per year basis. All costs are in 2016 U.S. dollars

Fig. 4

Incremental Cost and Effectiveness of MPK in Comparison to NMPK in K3/K4 Amputees, Note: MPK: microprocessor-controlled knees; NMPK: non-microprocessor controlled knees. QALY: quality adjusted life year. All costs are in 2016 U.S. dollars