In a new study published in the journal Prosthetics and Orthotics International, Mayo Clinic researchers describe the direct medical costs of falls in adults with a transfemoral amputation. In this type of amputation, the leg is amputated above the knee. This work “provides a comparison for policymakers when evaluating the value of more expensive technologies,” say the authors.

Of those who receive a prosthetic leg and knee, the policies that govern insurance payments grant basic mechanical knees for most. Despite growing data that newer technology reduces falls and improves physical capabilities, only high–functioning patients (based on mobility and activity levels) are deemed eligible for a knee with microprocessor technology.

“We want to help provide the best quality of life and prosthesis for each individual,” says Benjamin Mundell, PhD, the study’s lead author. Dr. Mundell, a trained health economist who is currently a medical student at Mayo Clinic School of Medicine, says, “It is important to look beyond the initial cost differences of a microprocessor knee compared to a mechanical knee and understand what downstream costs might be avoided with a better prosthesis.”

“Microprocessor knees are designed to help improve balance and reduce falls,” he says. “The fear of falling for those with mechanical knees likely reduces their overall physical activity and if they do fall and require hospitalization, the cost of care is almost as expensive as a microprocessor knee.”

Using the Rochester Epidemiology Project, a health records linkage collaboration in Minnesota and Wisconsin, the team examined the records of 77 individuals receiving a transfemoral amputation between 2000 and 2014. They found that 46 of these patients had received a prosthetic knee. Of these, 22 individuals experienced 31 falls that resulted in an emergency department visit or hospitalization. If they fell more than once during an 18–month period, both incidents were excluded from the cost analysis to prevent misalignment of costs.

What the researchers found, using standardized Medicare cost data from the Rochester Epidemiology Project’s new Cost Data Warehouse, was that the average additional cost in the 6 months following a fall can be substantial. The additional fall cost for individuals requiring an emergency department visit was $18,000. For patients who had to be hospitalized, this extra expense was more than $25,000.

“Understanding the costs is part of basic health economics,” says Kenton Kaufman, PhD, the study’s senior author, who is a biomedical engineer and orthopedics researcher at Mayo Clinic. “This study quantifies the cost of falls that require medical attention – providing evidence that it may not be economical to withhold microprocessor knees from patients with moderate ambulatory capabilities.”

He believes the costs to patients are much higher than the study shows.

“We know our cost estimate underestimates the true cost of a fall, because we didn’t include indirect costs, such as lost wages, caregiving expenses and transportation costs,” says Dr. Kaufman.

Medicare Functional Classification Level 2, in which the patient is described as having “the ability or potential for ambulation with the ability to traverse low–level environmental barriers, such as curbs, stairs or uneven surfaces,” nets a mechanical knee.

To be considered Level 3 or 4 (on a scale 0–4), and thus eligible for the microprocessor knee, a patient needs extensive physician documentation that he or she is likely to engage in activities that would use the leg more than the normal day–to–day walking, stairs, etc., that are part of an average American adult’s lifestyle.

“We hope that our research increases understanding of the cost–benefit equation from the patient’s perspective,” Dr. Kaufman said.