The studies, which looked at safety and outcomes in both femur-level (above-the-knee) and tibia-level (below-the-knee) OI, were presented at the 2026 Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS) in New Orleans this week.

“Osseointegration represents a significant advancement in the field of prosthetics for patients who have had a limb amputation, and interest is building rapidly,” said Jason Hoellwarth, MD, director of research in the Limb Lengthening and Complex Reconstruction Service and the Osseointegration Limb Replacement Center. “At HSS, we have performed more OI surgeries than any other hospital in the United States, treating more than 300 patients since 2017. We have found that osseointegration provides improved mobility, comfort and quality of life for patients when compared to a standard socket prosthesis.”    

Study 1: Femur and Tibia Press-Fit Osseointegration - A Comparison of Safety and Outcomes

“There are no studies in the scientific literature focusing on differences in safety and outcomes of patients who underwent transfemoral osseointegration as compared to those who had transtibial osseointegration,” said Taylor J. Reif, MD, an orthopedic surgeon in the Osseointegration Limb Replacement Center at HSS who presented the research. Dr. Reif and colleagues set out to compare safety, clinical, and quality-of-life outcomes in these two patient groups.

Dr. Hoellwarth, co-author of the study, noted that osseointegration was originally considered primarily for patients with femur-level amputations, since they fared much worse with a socket prosthesis than individuals with tibia-level amputations. “It was widely believed that patients with a below-the-knee amputation did well enough with their socket prosthesis and therefore would not derive significant benefit from osseointegration. Our study directly challenged that perspective.”

Researchers reviewed 147 OI procedures: 83 femur-level and 64 tibia-level. Both groups experienced substantial improvements in mobility and overall patient satisfaction, and there were no significant differences in the rate of adverse events.

“Contrary to widespread assumptions, our research found that tibia osseointegration patients have as much to gain from the surgery as femur OI patients,” Dr. Reif noted. “Therefore, any individual with a lower-limb amputation who is dissatisfied with their current socket prosthesis should be evaluated for osseointegration if they would like to pursue that option.”

Study 2: Primary Amputation with Osseointegration Versus Osseointegration for Existing Amputation

HSS researchers set out to compare safety and outcomes in patients who had osseointegration performed at the same time they had an amputation versus the more commonly performed osseointegration in individuals with an existing amputation.

The study included patients who had lower-extremity osseointegration with a minimum of one-year follow-up at HSS. There were 139 OI procedures: 81 femur-level and 58 tibia-level. Fifteen patients had simultaneous amputation and OI (4 femoral and 11 tibial), while 124 patients had OI for an established amputation (77 femoral and 47 tibial). 

The researchers found that both groups of patients—those undergoing osseointegration at the time of their amputation and those who had osseointegration with an existing amputation—achieved comparable gains in mobility and quality of life. There was no significant difference in adverse events between the two groups.

“Our research challenges the current paradigm that individuals with amputations should first try conventional socket prosthetics and only consider osseointegration if they are dissatisfied with their prosthesis,” said Dr. Reif, who presented the study. “It would be reasonable to offer simultaneous amputation and osseointegration to select, well-informed patients who prefer to bypass the trial of a socket prosthesis.”

Study 3: Safety and Early Experience of Osseointegration Limb Replacement with Custom-Fit Implants

HSS researchers set out to review the early outcomes of osseointegration with custom-made 3D-printed implants, which may be required for certain patients to obtain an ideal fit.

“Some designs of press-fit osseointegration implants have standard curvatures and contours with patient-specific length, leading to difficulty fitting the shape of the residual bone in some cases,” Dr. Hoellwarth explained.

Dr. Reif, who presented the study at the AAOS meeting, noted that additive manufacturing using electron beam melting (EBM) allows the production of precision osseointegration implants to achieve an optimal fit, making it possible to reconstruct nearly any residual bone segment to meet an individual’s anatomical needs.

The HSS researchers retrospectively reviewed the records of 19 patients at HSS who underwent osseointegration with custom 3D-printed implants planned from a preoperative CT scan. Patients included those who had above-the-knee, below-the-knee and above-the-elbow osseointegration procedures between May 2024 and March 2025.

The investigators found large, statistically significant improvements in patient-reported outcome scores following OI, and a significant increase in prosthetic use was observed in those who had used a socket prosthesis before OI surgery.  

Dr. Reif noted that the custom EBM osseointegration implants avoided intraoperative distal chip fracture, which can sometimes occur when using standard OI implants, and there was no loosening of the custom implants. “We found that short-term functional outcomes were similar to standard osseointegration implants,” he added. “Further studies are warranted to assess the long-term outcomes and durability of custom implants.”

Study 1 - Femur And Tibia Press-Fit Osseointegration - A Comparison of Safety and Outcomes (Zachary Glassband BA, Taylor J. Reif MD FAAOS, S. Robert Rozbruch MD FAAOS, Jason S. Hoellwarth MD)

Study 2 - Primary Amputation with Osseointegration Versus Osseointegration for Existing Amputation (S. Robert Rozbruch MD FAAOS, Mohamed Abdelaziz Elghazy MD, Zachary Glassband BA, Taylor J. Reif MD FAAOS, Jason S. Hoellwarth MD)

Study 3 - Safety and Early Experience of Osseointegration Limb Replacement with Custom-Fit Implants (S. Robert Rozbruch MD FAAOS, Zachary Glassband BA, Jason Hoellwarth MD, Taylor Reif MD FAAOS)

The procedure provides improved mobility, comfort, and quality of life compared to a standard socket prosthesis, according to Jason Hoellwarth, MD, a highly specialized orthopedic surgeon at Hospital for Special Surgery (HSS) in NYC and at HSS Long Island.   

Nick, who is 45 and lives in Saint James, Long Island, credits Dr. Hoellwarth and the team at the HSS Osseointegration Limb Replacement Center with giving him his life back. A congenital condition that caused a leg bone deformity and a severe ankle injury when he was 11 years old led to two major reconstructive surgeries with lengthy recoveries. As time went by, he started to experience pain that got progressively worse, hindering his ability to walk, work out, and do his job. By age 40, he says it was "hard to express the level of pain." A motorcycle accident when he was 43 was the final blow that “annihilated” his left ankle.

By the time Nick found out about osseointegration, he says the pain had become almost unbearable, and he was in a “very dark place.” He had seen several specialists who ordered x-rays, CT scans and MRIs. “The doctors all said my condition would require extensive and complex reconstructive surgery with a recovery of up to two years. I didn’t want to go down that path again, and the long-term outcome could not be guaranteed,” Nick explains. 

In his online research, Nick found HSS, the most experienced hospital in the United States for osseointegration to treat people with a transtibial (below the knee) amputation, which is what he would have. After an initial meeting with a highly experienced foot and ankle specialist at HSS who also explained that multiple surgeries and lengthy recoveries would be required, Nick scheduled a second consultation – this time with Dr. Hoellwarth – to see if osseointegration would be right for him. 

“I informed Nick that a single surgery of amputation with osseointegration would provide a rapid return to all-day pain-free mobility. So Nick went forward, had the surgery, and never looked back,” Dr. Hoellwarth says.  

After his recovery and a short period of physical therapy, Nick says he regained the life he had longed for − pain-free and walking without a limp for the first time in 30 years. Some of his journey is posted on Instagram. He works out intensely at the gym and performs a physically demanding job as operations manager of a large plant nursery. And now he aims to help others with limb loss. He told a friend at his gym about osseointegration. His friend, who was struggling with a standard socket prosthesis, had never heard of it. After consulting with Dr. Hoellwarth, he decided to have the surgery.