Transhumeral patients who underwent osseointegration presented a 5-year survivorship of 80% and a 38% 5-year incidence of infectious complications related to the skin penetration site, according to study results. However, infections were easily managed with nonoperative treatment, making osseointegration a potential alternative to conventional socket arm prostheses.
“Every implant, such as hip prosthesis, tooth implants, that doctors put in a patient’s body is a foreign body. This is unnatural, which is the reason why the human body reacts and eventually rejects the implant after some time,” Georgios Tsikandylakis, MD, FEBOT, of the Department of Orthopaedics at the Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden, told O&P Business News. “In the case of bone-anchored amputation, we still do not know how long these prostheses last or what kind of complications are associated with them. The purpose behind this study was to report on how long these remain well fixed in the arm and to identify and document the various complications that have occurred in upper arm amputees who have been treated with this method during the past 20 years. Moreover, we looked at how the skeleton changes with time around the implant.”
Osseointegration survival, complication rate
Researchers performed 18 primary osseointegrated percutaneous implants and two implant revisions between 1995 and 2010. Of these patients, 16 patients were available for follow-up at a minimum of 2 years and 13 patients at 5 years, including all transhumeral amputees who received osseointegrated prostheses and represented approximately 20% of all transhumeral amputees evaluated for potential osseointegration during the time period. Patients included in the study had amputations resulting from trauma or tumor, inability to wear or severe problems wearing a conventional socket prosthesis and compliance. Researchers retrospectively evaluated medical charts and radiographs.
Overall, study results showed a 2-year survival rate of 83% and a 5-year survival rate of 80%. Early loosening was the cause of two primary and one revised implant failure and removal, while ipsilateral shoulder osteoarthritis and subsequent arthrodesis was the cause of a fourth implant being partially removed. Researchers found superficial infection of the skin penetration site was the most common adverse event. This was followed by skin reactions at the penetration site, incomplete fracture at the first surgery, defective bony canal at the second surgery, avascular skin flap necrosis and deep implant infection. According to study results, the most common radiologic finding was proximal trabecular buttressing followed by endosteal bone resorption and cancellization, cortical thinning and distal bone resorption.
“The results showed that osseointegrated implants could be considered as an alternative to conventional socket arm prostheses especially in the case of very proximal amputations where the suspension of a socket prosthesis is problematic and their harness causes discomfort,” Tsikandylakis, who is also involved in the Department of Orthopaedics at Sahlgrenska University Hospital, Gothenburg, Sweden, said. “Further studies should focus on the quality of life and prosthetic usage that osseointegrated amputation prostheses provide transhumeral amputees in comparison to conventional socket prostheses. Moreover, the long-term significance of bone remodeling around the implants should be studied.”
Osseointegration vs. socket
Through patient feedback, researchers found that use of an osseointegrated prosthesis made it easier for amputees to put on and take off their prosthetic limbs, and also allowed amputees with short residual limbs to wear a prosthesis comfortably. Amputees also reported perceiving vibrations of the prosthesis through their skeleton, which allowed them to feel like they had a leg again.
While osseointegration has positive outcomes, as an invasive surgery there is also the risk for complications, Tsikandylakis said.
“Since the implant penetrates the skin, it comes in direct contact with the outer environment and bacteria that naturally live in the skin. This causes a local inflammation in the skin penetration area such as redness and discharge that may lead to infections,” Tsikandylakis said. “The amputee has to take great care of the skin penetration area by cleaning it twice a day.”
However, even with the risk of infection, patients have reported better outcomes after undergoing osseointegration, he said.
“Transfemoral amputees with osseointegrated prosthesis have reported better sitting comfort and fewer office visits for adjustment of their prosthesis compared to amputees with socket prosthesis. Prosthetic using and hip range of motion is also increased,” Tsikandylakis said. “In transhumeral amputees, there are still no comparative studies available.” — by Casey Tingle
Disclosure: Tsikandylakis received funding from the LUA project, University of Gothenburg and from the Johan Janssons Foundation, Karlskoga, Sweden.