Autumn Years Summer 2024

HEALTH & WELFARE

3D Printing Transforms Joint Replacement Surgery By Robin Frank

A 3D printer at HSS produces custom joint replacement implants for complex cases.

I s the excitement over 3D printing war ranted? As the number of products cre ated with 3D printers continues to grow, its value is hard to deny. A process that uses computer-aided design to create solid three-dimensional objects, the technol ogy is expected to grow exponentially in coming years. Also known as additive manufactur ing—objects are created by adding material one layer at a time—3D print ers are used to make jewelry, tools, car parts and even houses. In health care, 3D printing has enabled solutions for some of the most challenging medical problems, according to Dr. Michael Ast, chief medical innovation officer at Hospital for Special Surgery (HSS) in New York City. In orthopedics, sophisticated 3D print ers are now manufacturing custom-made joint replacements with a high degree of precision and speed when a standard “off the shelf” implant won’t work, says Dr. Ast, a hip and knee surgeon who sees patients at HSS Paramus. For most people needing joint replacement surgery, tradi tional implants, which come in a variety of sizes, will fit. However, widely available implants do not work for everyone, and that is where the extraordinary capabilities of 3D print ing come in. For patients requiring highly complex reconstructive surgery, the ability to customize a joint replacement has been a game-changer, according to Dr. Mathias Bostrom, associate surgeon-in-chief at HSS. “For highly specialized hip and knee reconstructions, custom implants have transformed the way we can treat patients with debilitating orthopedic problems,” he says.

From model to actual implant Dr. Bostrom and his colleagues initially began using a 3D printer that HSS acquired more than a decade ago to quickly manufacture a plastic model—an exact replica of a patient’s knee, hip, shoulder or elbow—prior to per forming a highly complex joint replacement. “We get a CT scan and from that we can create an actual model of the patient’s joint to help with planning the surgery before we go into the operating room,” explains Dr. Mark Figgie, chief emeritus of the Surgical Arthritis Service at HSS. “Having the model before surgery has revolutionized the plan ning process of these difficult cases, helping us make sure we’re doing the right thing and getting the right fit.” Fast forward 10 years, and the technol ogy has advanced to where 3D printers are now producing the titanium implant that goes into the patient. Often used for complex or re-do hip replacement surgeries, the specially designed implants may also be the last and best hope for patients need ing a complicated knee, shoulder or elbow replacement. By the time patients come to the Com plex Joint Reconstruction Center, they know they have a complicated problem, accord ing to Dr. Bostrom. “Sometimes the center is thought of as being the ‘the end of the line’ for these patients,” he says. They are grateful when they learn that a solution is in sight. Because all new medical devices require approval by the Food and Drug Administra tion, gaining permission to use a patient specific 3D-printed implant can be a slow process. A waiver known as “compassionate use” must be obtained. Although it may take weeks or sometimes months, patients say it is worth the wait.

In 2021, HSS, in collaboration with LimaCorporate (recently acquired by Eno vis), became the first hospital in the Unit ed States to house a 3D printing facility onsite for custom joint replacements. The FDA-regulated center, owned and oper ated by Enovis, has enabled the hospital’s orthopedic surgeons and design engineers to work closely with Enovis engineers to develop patient-specific prostheses for the most challenging orthopedic condi tions. “Compared to traditional implant manufacturing, the magic of 3D printing is the ability to produce so many more complex shapes and designs in a fraction of the time,” explains Douglas Leach, vice president of Device Innovation at the HSS Innovation Institute. At the Complex Joint Reconstruction Center at HSS, orthopedic surgeons see patients with severe deformities, massive bone loss or failed joint replacements that need to be redone. For these patients, a custom-made 3D-printed implant could restore function and mobility or even save their limb. Implants made for specific patients have relieved relentless pain. They have enabled wheelchair-bound patients to walk again, Dr. Bostrom says. Made of titanium, the implant is manu factured from very fine metal powder, which is poured onto a platform and leveled carefully. A laser or electron beam heats the powder layer and melts the material, which fuses to the layer below. Material is added layer by layer to create the implant. To date, the hospital has designed or manufactured more than 150 custom implants, not only for patients of HSS doctors, but for those of orthopedic surgeons around the country.

20 AUTUMN YEARS I SUMMER 2024