Leg amputees who receive bone-anchored prosthetics report high levels of satisfaction compared with those who receive conventional devices, according to new study findings published in JBJS Open Access by researchers at Hospital for Special Surgery (HSS) in New York City.

Osseointegration prostheses are a relatively new form of prosthetic technology. The approach involves surgically installing a titanium rod into a patient’s remaining bone—such as the tibia or femur in the leg—which in turn attaches to a prosthesis that allows ambulation. The technology avoids the need for traditional sockets against which limb stumps rest, an interface that produces friction that can generate significant pain and discomfort for amputees and frequently requires repair or revision. 

Although osseointegration devices are available to patients in Europe and elsewhere, the US Food and Drug Administration has yet to approve the technology. But the agency allows a limited number of patients to receive the implants through humanitarian exceptions.

“This is a disruptive technology to improve the life quality of amputees. With a direct skeletal connection of the prosthetic limb, amputees report big improvements in function, comfort, balance, proprioception and even emotional connection with their limb.”

— study co-author S. Robert Rozbruch, MD, Chief of the Limb Lengthening and Complex Reconstruction Service and Director of the Limb Salvage and Amputation Reconstruction Center at HSS

Reviewed Medical Records

For the new study, Taylor J. Reif, MD, an orthopedic surgeon and a member of the Limb Lengthening and Complex Reconstruction Service, Dr. Rozbruch and their colleagues reviewed the medical records of 31 men and women who underwent osseointegration procedures at HSS starting in October 2017 under compassionate use exceptions. Of those, 18 had implants in the femur, or thigh bone, and 13 had implants in the tibia, the bone below the knee.

The primary outcome of the study assessed changes in the Questionnaire for Persons with a Transfemoral Amputation (QTFA), which patients complete before and after surgery. The researchers used the same questionnaire for patients with tibial amputations. They also gathered data on a range of quality-of-life measures including patient-reported functional activity, mental health, pain and self-image, as well as adverse events such as serious infections, fractures at the site of the implant and other complications of the procedure.

Researchers found that scores across all domains of the QTFA improved significantly throughout the study period. Prosthetic mobility rose from 49.7 to 81.4, while prosthetic problems fell from 46.4 to 9.1. Patients also experienced substantial gains in function with the implants, as measured by 2- and 6-minute walking tests.

The benefits of the devices extend beyond the raw numbers, Reif says.

“The scores going up is great, but that doesn’t necessarily capture what we’re seeing in the clinic, which is smiles on people’s faces and the expressions of gratitude for how much their lives have changed. It’s totally life-altering.”

Although some patients did experience early complications, nearly all (93%) were managed without removing the implant. Encouragingly, while some patients developed minor infections where the titanium post exits the skin (an opening called a stoma), most of these resolved with the use of oral antibiotics. Only one patient had an infection in the bone itself leading to removal.

The bond between the titanium implant and the bone is so strong that patients are able to rapidly resume physical activity. In some cases, patients can return to vigorous, weight-bearing exercise such as running within 6 months to 1 year after the procedure.

Patients Tend to Be Young, with Traumatic Injuries

As the data showed, patients who seek osseointegration prostheses tend to be young, and most had sustained catastrophic injuries to their legs in vehicular accidents or other traumatic events.

“The older population of patients have become accustomed to their sockets or using a wheelchair,” Reif says. “But as this technology expands and more surgeons start to employ it, I think the age that these are implanted also will expand in both directions.”

“No implant has a perfect track record,” he adds, “but when you combine the functional gains that these patients are experiencing with improvements in their quality of life, a small risk of infection or fracture is acceptable to them, as well as to the orthopedic community.”

[Source(s): Hospital for Special Surgery, PR Newswire]

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