The pair had the prosthetic made with a laser sintering process. This technique is considered an additive manufacturing technique not unlike 3D printing that builds a product layer by layer.
An athlete all his life, Howard was a distance runner for the University of California, Irvine cross-country team before a diagnosis of osteosarcoma and amputation of his left leg just below the knee. He was fitted with a prosthesis, and went on to set amputee world records in several events. So, Mr. Howard is probably not considered your average amputee, but may serve to raise the bar on what amputees everywhere can and will do in the future.
When Ott introduced him to climbing in 2008, standard prosthetic shapes didn’t work well with his specialized footwear. Ott got out her laptop, opened an engineering CAD program and, on-the-spot, created what Howard described: an aggressive climbing shoe with a downturned toe—like a banana.
How best to manufacture the new prosthesis? Ott immediately thought of an additive manufacturing process called direct metal laser sintering (DMLS) that she had encountered in her work at a major aerospace company. The technology is often used to build one-of-a-kind prototypes and end-use parts with a turnaround time of just a few hours. Using traditional machining techniques would have left nuts and bolts sticking out of the prosthetic. Not conducive to climbing, of course.
Morris Technologies, an Ohio firm that specializes in additive manufacturing and is the largest deployer of DMLS in the world, did the job. Ms. Ott says they completed the prosthesis in time for Mr. Howard’s Christmas present: His smile was priceless, she adds.
Fabricating the approximately 6-by-3-by-2-inch, smooth-edged foot out of commercial-grade titanium (Ti64) took about forty hours on a system manufactured by German-based EOS GmbH, developer of DMLS technology. The finished five-pound foot was a single-piece construction, hollow (to minimize weight) and with no seams or fasteners. A separate vendor coated it with a rubber used for climbing shoe soles.
As designs go, Howard’s climbing prosthesis was fairly simple, the team explains. Specialized prostheses (replacements) and orthoses (braces) for competitive disabled athletes who run, ski, and cycle can be more complex. Warden points out that the DMLS process is also perfect for producing medical products with even more critical geometries. This could include orthopedic implants for hips, knees, shoulders, ankles, and even spines, as well as patient-specific surgical instruments. A growing list of materials—including biocompatible plastics and metals—is enabling Morris engineers to consider laser sintering for a number of cutting-edge medical applications.
Climbing as much as three times a week when he can get away, Mr. Howard has now had a number of opportunities to try out his new prosthesis in the field. His northern California test sites have included the granite of Tahoe’s Lover’s Leap, the single-pitch trad routes of Phantom Spires, sport climbing at Luther Spires, and the crevice and chimney systems of nearby Sugarloaf. He has also climbed with it on dome and crack routes in Yosemite.
They plan to design one shaped like a triangle for pure crack climbing and another with less downturn for more slabby conditions. Mr. Howard adds: “It’s like changing tires on a race car. You would just switch your leg for different climbs.”
You can read the full detailed news release at BusinessWire. Image provided by BusinessWire.
