Each year, hundreds of patients visit the Amputee Clinic at UAB Spain Rehabilitation Center to be fit for prostheses after complications of diabetes, motor vehicle accidents and a wide range of other conditions. A new grant from UAB’s Health Services Foundation-General Endowment Fund awards program is funding the purchase of an advanced 3D printer that will allow those patients to receive their prostheses faster, at lower cost and with an even better fit, says the clinic’s director, Conley Carr, M.D. The printer will also produce custom orthoses for UAB patients needing braces after a stroke or other condition, he adds.
This will be the first clinic in Alabama, and one of the few nationwide, to offer 3D-printed sockets for prosthetics, says Carr, an assistant professor in the Department of Physical Medicine and Rehabilitation and medical director of the department’s Orthotics and Prosthetics Lab. “If you look in the literature, it’s hard to find people doing this kind of work,” he said. But the benefits are so great that he predicts this will change rapidly in the coming years, especially at larger medical centers such as UAB. Investing in this kind of pioneering technology to improve patient care is one of the main motivators for the HSF-GEF program, which has invested nearly $60 million in internal grants since its founding in 1996.
Nationwide, the demand for prostheses is growing fast. According to a study published in 2024, the number of people living with limb loss in the United States will double by 2050, largely driven by predicted increases in vascular disease and diabetes.
Photo: Andrea Mabry
Those national trends are reflected in the Amputee Clinic’s patient volume, Carr says. Around 70 percent of the clinic’s patients have lost a limb due to vascular/circulatory disease or diabetes, he notes. These inter-related diagnoses are closely tied to aging. “We’re getting busier over time,” Carr said. “We are hiring and growing rapidly.”
Once their new 3D printer is installed in the coming months, Carr and Brian Mueller, certified prosthetist and clinic director of the Orthotics and Prosthetics Lab, expect to cut production times by nearly 60 percent. Costs will be lower, for both patients and the department, and patients can look forward to even better fit for their prostheses. “With 3D scanning and printing, we can create devices that are tailored to the patient’s unique physiology, minimizing medical complications such as skin breakdown or poor fit,” Mueller said. “The technology also allows for customized features, such as breathability and a mix of flexible and stiff design elements to enhance mobility, safety and comfort.”
Photos: Andrea Mabry
How prosthetics have been made
The traditional method for creating a prosthesis starts by making a plaster mold of the patient’s residual limb, Mueller explains. After the plaster hardens, a certified prosthetist such as Mueller would modify that mold by hand. “We remove material in areas where we want a tighter fit and add material where we want the patient to have more space,” Mueller said. The customized mold would then be covered with plastic that has been heated in an oven to create flexibility. Alternatively, a prosthetist might do a hand lamination with strips of resinous material. “It is very labor-intensive,” Mueller said. It is also limited to working hours, and because specialists such as Mueller and his team are in short supply, they are limited in how many prostheses they can create each week.
Several years ago, Carr and Mueller received an HSF-GEF grant to purchase a 3D scanner and carving machine for the Orthotics and Prosthetics Lab. They use the scanner to create a digital file of the patient’s limb, then send it to the carver to transform that file into a shaped piece of foam, which can be cast in fiberglass. “That took us halfway to our goal” of a fully digital operation, Carr said. At the time, 3D printing was so expensive and slow, and the quality was so inferior, that it was not suitable for regular clinic use, Carr says.
Now we can “go right to plastic”
Technology improvements in the past few years mean that, with their new grant, Carr and Mueller will complete their original vision. The 3D printer will turn digital files from the 3D scanner directly into a finished prosthesis. “We can create the shape digitally and go right to plastic,” Carr said. Each prosthesis will take several hours to print, but the 3D printer can be left to run overnight or on the weekends, Mueller says.
Another advantage of combining 3D scanning and 3D printing is reproducibility. Although the plastics used for prostheses are extremely durable, they can eventually wear out or be damaged. Having digital files created for each patient means that replacements can be made quickly and can be a perfect replica each time, Carr notes. “We have patients who have used the same socket for years and years,” he said, “and they want the exact same thing. We can pull up the file and reproduce it exactly.”
3D printing for orthoses, too
Carr and Mueller say the 3D printer will also help create customized braces for patients who need orthoses. “These can come from all over the hospital,” Carr said. “Someone who has had a stroke and has foot drop may need bracing for that foot, while patients from neurosurgery might require a spinal brace.” Not all of these patients will require custom bracing, because off-the-shelf options are available; but Mueller estimates that around a third of patients will receive 3D-printed braces.
The one downside to industrial-scale 3D printing is that it involves a “very large piece of equipment,” Mueller said. The new machine will take up a sizeable portion of the Orthotics and Prosthetics Lab. Carr and Mueller are hoping to expand their space to keep up with demand as other clinical services move from the existing Spain Rehabilitation Center to the new UAB Rehabilitation Pavilion, which is set to open later this year. “We often have more practitioners available than exam rooms,” Carr said. “Additional space will allow us to meet the needs of more patients.”