Influence of Prosthetic Foot Stiffness on Transtibial Osseointegrated Bone-Anchored Limb Outcomes

NIH/NICHD/NCMRR R01 1R01HD119003-01  

Bone-anchored limbs (i.e., osseointegrated prostheses) are a promising alternative for the near one-third of individuals with limb amputation who cannot use socket prostheses by providing a direct fixation of the prosthesis to the residual limb via an osseointegrated implant, which allows for the amputated limb to be loaded in a more normative fashion. Although proper loading between the bone and implant is pivotal to promote and maintain osseointegration, which is required for physiological loading and thus positive outcomes, evidence surrounding the role of how prosthetic componentry influences force transmission and functional outcomes in this population currently does not exist. By implementing a clinical trial utilizing cross-over study design in which individuals with transtibial amputation using either a bone-anchored limb or standard socket prosthesis will perform activities of daily living with varying prosthetic foot stiffness categories, the findings of this proposal will address a critical knowledge gap pertaining to the role of componentry on multi-loading domain outcomes. 

This work is supported by the National Institutes of Health.

Effect of Osseointegrated Prostheses on the Pathogenesis of Hip Osteoarthritis in Patients with Lower Limb Loss

NIH/NIAMS K01 AR080776

Osseointegrated prostheses are a novel alternative to a socket that directly mount the prosthesis to the residual limb via a bone anchored implant providing more normative load transmission between the ground and residual limb; yet its effect on the mechanical environment of the joint remains unknown. This project will be the first to rigorously investigate the longitudinal effects of osseointegrated prostheses across multiple biomechanical domains using medical imaging and computational modeling. By quantifying its effect on muscle composition, cartilage loading mechanics, and cartilage health, we can begin to determine if prosthesis osseointegration plays a positive role of osteoarthritis progression in this population differently than a socket, which has vast clinical implications including informing targeted rehabilitation and patient eligibility criteria.

This work is supported by the National Institutes of Health.

Dynamic Bone-Implant Loading in Osseointegrated Prostheses

NIH/NICHD/NCMRR R03 HD111012

Osseointegrated prostheses are a novel alternative to a socket prosthesis that directly mount the prosthesis to the residual limb femur via a bone anchored implant, which allows the amputated limb to be loaded in a more normative fashion. Early evidence is highly promising regarding the improvement in function and quality of life after osseointegration; however mechanical failure due to implant loosening or periprosthetic fracture caused by pathologic loading at the bone-implant interface exists in a small subset of this population, yet the mechanistic understanding as to why remains poorly understood. The findings of this proposal will be fundamental in the understanding of bone-implant loading mechanics and failure mechanisms, which can be used to improve the efficacy of targeted post-surgical rehabilitation by normalizing loading following prosthesis osseointegration.

This work is supported by the National Institutes of Health.

Transfemoral Osseointegrated Prosthesis Limb-Load Symmetry Training

DOD/CDMRP/OPORP OP220013

Osseointegrated (OI) prostheses are a novel alternative to a socket prosthesis that directly mount the prosthetic limb to the base of the amputated limb through a medical implant, which allows the amputated limb to be loaded more normally. Within our clinic, this new prosthesis has been met with astoundingly positive improvements in mobility and quality of life. However, our pilot evidence also demonstrates that asymmetrical joint loading caused by persistently altered movements persists in these patients one year after OI implantation. This is important because the way the limb is loaded is vital to long-term outcomes in this population. Too high of loads, either acutely or over a prolonged period, may result in bone fracture while too low of loads may not promote proper bone healing between the bone and implant. As such, the primary focus in rehabilitation is driven by tight restrictions on progressive loading in the acute rehabilitation phase to stimulate osseointegration between the bone and implant to ready the limb for activities of daily living. However, due to its novelty, current standard of care rehabilitation protocols immediately following OI prosthesis implantation are based on very limited evidence and lack validation. Furthermore, a rehabilitation paradigm that that targets the maintenance of healthy loading once acute rehabilitation has been concluded currently does not exist. Therefore, our overarching objective is to develop the first-of-its-kind Phase I clinical trial to test the feasibility of a limb-load biofeedback training intervention in patients with OI prostheses.

This work is supported by the Department of Defense.