Can ‘Microprocessor’ Knees Reduce Amputee Falls?

Can a “Microprocessor” knee implant reduce the rate of falling for active amputee patients?

A research team from the Hanger Clinic in Texas along with researchers from the University of Nebraska, University of Utah, and University of North Carolina tackled that question and designed a study to collect data from patients who’d been implanted with a “microprocessor knee” after undergoing lower limb amputations. As a patient population, this group tends to have a high incidence of falls. Further, above-the-knee amputations and diabetes/vascular disease are also risk factors for falls in amputees.

Microprocessor knees are a subset of the “smart” knee category—one of the fastest growing and most interesting new forms of knee implant. All types of “smart” knees have sensors which detect movement, process that data and, often, communicate automatically with an internet based network. The microprocessor knees which were the subject of this study employ sensors within the implanted knee to constantly gather movement and timing data, which the knees then interpret to make any necessary adjustments. The sensors detect stumbles in real time, automatically adjusting the knee’s stiffness and allowing the user to catch themselves to avoid a fall.

The paper that resulted from that study, “Stability and Falls Evaluations in AMPutees (SAFE-AMP 1): Microprocessor knee technology reduces odds of incurring an injurious fall for individuals with diabetic/dysvascular amputation,” was published in the January 13, 2022, edition of Assistive Technology.

The research team included 881 amputee patients in the study, 744 of whom did not receive a microprocessor-controlled knee. The team found that 16.3% of non-microprocessor-controlled knee users experienced an injurious fall compared to 7.3% of those who did have that technology. In short, the research team found that a microprocessor-controlled knee can decrease the risk of a fall by 250% for individuals with amputation due to diabetes or vascular disease. Interesting, the team also found that not giving a diabetic patient a microprocessor-controlled knee increases their risk of falling, more than the risk associated with aging.

Source: Hangar Clinic

James Campbell, PhD, who serves as Senior Vice President & Chief Clinical Officer for the study sponsor and supplier of the “smart” knee, Hanger, Inc., told OTW, “Our SAFE-AMP findings illustrate that further work is warranted to better understand how all possible orthotic and prosthetic care solutions can help improve clinical outcomes and quality of life for the diabetic patient population. Going forward, future research will examine the need for greater access to appropriate rehabilitation solutions for below and above-knee amputees in patients with diabetes.”