Three studies challenge who benefits from bone-anchored prosthetics after amputation

AAOS 2026 Annual Meeting, March 2026

The conventional wisdom in prosthetics has been straightforward: if you lose a leg above the knee, you will probably struggle with a socket prosthesis. If you lose it below the knee, you will manage reasonably well. Osseointegration, the surgical attachment of a prosthetic limb directly to bone, was developed primarily for the first group.

Three new studies from Hospital for Special Surgery (HSS), presented at the 2026 American Academy of Orthopaedic Surgeons meeting in New Orleans, challenge that narrative on multiple fronts.

Below-knee patients benefit just as much

The first study compared safety and outcomes between 83 femur-level (above-knee) and 64 tibia-level (below-knee) osseointegration procedures. Both groups showed substantial improvements in mobility and overall satisfaction. Adverse event rates did not differ significantly between the two groups.

Taylor Reif, an orthopedic surgeon at HSS who presented the research, noted that the results directly contradicted widely held assumptions. The belief that below-knee amputees do well enough with socket prostheses to make osseointegration unnecessary was not supported by the data. Both groups had comparable gains.

Jason Hoellwarth, director of research in the Osseointegration Limb Replacement Center, provided context: HSS has performed more osseointegration surgeries than any other hospital in the United States, treating more than 300 patients since 2017. That volume gives the institution an unusually large dataset to draw from.

Skipping the socket altogether

The second study tackled another entrenched assumption: that patients should first try a conventional socket prosthesis before considering osseointegration. Researchers compared 15 patients who had osseointegration performed simultaneously with their amputation against 124 patients who had osseointegration after living with an established amputation.

Both groups achieved comparable gains in mobility and quality of life. Adverse events did not differ significantly. The finding suggests that for well-informed patients who prefer to bypass the trial of a socket prosthesis, simultaneous amputation and osseointegration is a reasonable option.

This challenges the current clinical paradigm, which treats socket prosthetics as the default first step and osseointegration as a fallback for those who cannot tolerate conventional prostheses.

Custom 3D-printed implants avoid fracture complications

The third study examined 19 patients who received custom osseointegration implants manufactured using electron beam melting (EBM), a form of 3D printing. These implants were designed from preoperative CT scans to match each patient's specific anatomy. Standard press-fit implants have fixed curvatures that do not always accommodate the shape of the residual bone, which can lead to intraoperative chip fractures during insertion.

The custom implants avoided that problem entirely. No distal chip fractures occurred, and no implant loosening was observed. Patient-reported outcome scores showed large, statistically significant improvements, and prosthetic use increased among patients who had previously used socket prostheses.

Short-term functional outcomes were similar to those achieved with standard osseointegration implants. Longer-term data on durability and outcomes are still needed.

What remains uncertain

All three studies come from a single institution, which limits generalizability. HSS has unusually high surgical volume and experience in osseointegration, and results may not be replicated at centers with less experience.

The studies also focus on safety and functional outcomes over relatively short follow-up periods. Osseointegration carries specific long-term risks, including infection at the site where the implant exits through the skin, and these risks need to be evaluated over years, not months.

Cost and access remain practical barriers. Osseointegration surgery is more complex and expensive than socket fitting, and is available at only a limited number of centers. Whether these findings will change insurance coverage or referral patterns remains to be seen.