The objective of the proposed research is to evaluate outcomes associated with use of a promising new prosthetic technology for Service members and Veterans with lower limb amputation. Over the past 30 years, increasingly sophisticated prosthetic foot designs have been developed for people with lower limb amputation. The current standard-of-care for active individuals is an energy storing foot (ESF), a J-shaped foot made from carbon fiber that is generally suitable for walking and low-to-moderate impact activities. People with lower limb amputation who engage in high-impact activities like running may require a specialized prosthesis with a running-specific foot (RSF). RSF, while ideal for running, are not suited to walking because they lack a heel. Thus, people with lower limb amputation may need multiple prostheses, one with a high-performance RSF (for running) and one traditional ESF (for walking) in order to achieve optimal outcomes across a range of activities. Acquiring and maintaining multiple prostheses may not be ideal for many people with lower limb amputation, especially Service members who seek return to active duty.

Our clinical collaborator has developed a novel, modified prosthetic foot that integrates the features of both ESF and RSF designs. This modified running-specific foot (mRSF) is based on the RSF used by Paralympic and Olympic athletes around the world, but it has been extensively modified for daily use (walking) as well as high-impact activities (jogging, running, and sports). The mRSF therefore meets the need for a simple, robust, high-performance prosthesis that can be used for a wide range of functional activities. Initial feedback from users has been promising, as they have reported walking faster, farther, and with less energy with the mRSF compared to their previous ESF prostheses. Preliminary data we have collected support these perceptions, but research is needed to objectively evaluate this technology and assess its potential application among Service members, Veterans, and civilians with lower limb amputation secondary to trauma.

The proposed research is intended to address the need for objective, high-quality evidence of the functional outcomes that may be expected with use of this novel technology. We will conduct a rigorous study to compare outcomes achieved with the mRSF to those achieved with a traditional ESF in 30 people with lower limb amputation secondary to trauma. We will measure objective, performance-based outcomes important to Service members and Veterans with lower limb amputation, including gait quality, endurance, energy expenditure, and daily activity. We will similarly evaluate subjective, self-report outcomes that reflect users' experience, including perceived mobility, balance confidence, fatigue, activity restrictions, and satisfaction. Study results will ultimately produce quality evidence that can be used to guide clinical prescription of the mRSF.

The potential benefits of this research are increased knowledge of and access to a promising prosthetic technology that may improve users' functional performance, endurance, activity level, health, and quality of life. Evidence produced by this study will further translation efforts and help make this technology available to the more than 100,000 people in the United States with lower limb amputation secondary to trauma. Risks of using the mRSF in this study are minimal and do not exceed those encountered when walking with an ESF prosthesis in daily life.

We expect the results of this research will rapidly contribute to improved patient outcomes for Service members, Veterans, and civilians with lower limb amputation. By partnering with the mRSF developer and a global leader in prosthetics manufacturing in this research effort, we will be able to rapidly and effectively apply these research findings. We anticipate the mRSF technology will reach commercialization within the 2-year study period and the results of this research will be available to support clinical selection and prescription practices within the first 1-2 years following completion of the proposed research.

The proposed research will further our knowledge of a promising prosthetic technology and its ability to improve important functional and health-related outcomes in Service members, Veterans, and civilians with lower limb amputation. If successful, this research will help make this state-of-the-art technology available to those Service members and Veterans who have sacrificed much in service to our country.