Center for Limb Loss and MoBility

About the Center

Overview and Mission

The primary mission of the Department of Veterans Affairs Rehabilitation Research and Development (VA RR&D) Center for Limb Loss and MoBility is to improve the quality of life and functional status of Veterans who are at risk for lower extremity amputation and Veterans and service members who have undergone lower extremity amputation. To accomplish this mission, our investigative team includes orthopedic surgeons, physiatrists, engineers, psychologists, human motion biomechanists, foot/ankle biomechanists, epidemiologists, and prosthetists who work collaboratively to address research questions of importance to Veterans and the Veterans Health Administration.

An important secondary mission of our Center is to develop the next generation of investigators, which enables VA to continuously enhance the care it provides to Veterans. Lower extremity impairment, dysvascular amputation, and combat-related amputation will continue to be priority areas of rehabilitation within VA. To accomplish this secondary mission, we recruit trainees to participate in our research program from a breadth of academic fields including engineering, prosthetics, orthopedics, and rehabilitation medicine.

Our Center’s Limb Loss Prevention research aims to reduce functional and anatomical limb loss by exploring the disease processes that lead to aberrant limb function and by developing novel, state-of-the-art technologies for studying the foot. Our research focuses on two Veteran populations: those with musculoskeletal impairment at the foot and ankle, where pain and limitations in mobility are the key issues; and those at risk of lower limb amputation due to diabetes and foot ulceration, where loss of the foot or leg is a major concern. The goals of our research include: (1) quantitative comparison of different treatment options for foot deformities that can lead to loss of limb function, (2) insight into the pathomechanics of diabetic foot ulcer formation, and (3) novel research tools that can be employed in a wide range of clinical studies.

Our Center’s Prosthetic Engineering research focuses on reducing limitations in mobility and discomfort experienced by all major cohorts of Veterans with lower limb amputation, including those with amputation secondary to peripheral vascular disease and diabetes, the aging combat-injured Vietnam Veteran, and the young, active Operation Iraqi Freedom (OIF)/Operation Enduring Freedom (OEF) combat-injured amputee. Our research compares existing prosthetic technologies and develops innovative new approaches. The goals of our research include: (1) determining the efficacy of currently-prescribed prosthetic interventions and treatments and (2) investigating novel approaches that offer breakthrough advances to the current standard-of-care.

Our Center’s Translational Research focuses on issues that may impact clinical care in the near term to enhance function in Veteran amputees. These efforts are focused on two key areas: (1) evaluation of patient activation and self-management tools that improve and sustain functional outcome after lower extremity amputation with dysvascular etiology, and (2) development of outcome prediction models for both mobility at one year after amputation, and residual limb healing and mortality after incident amputation in this population. The goals of our research are to: (1) determine the effectiveness of patient tools to inform clinical care recommendations for the VA Amputation System of Care and (2) develop amputation prediction models that can be used as clinical tools to aid in the formulation of patient-specific decisions regarding the probable outcomes at each major amputation level with the aim of enhancing patient-centric decision making, reducing variability in care, enhancing outcomes, and reducing costs of care.

Key Impacts

During FY 2014, our Center’s key impacts included:

• Our team’s work on ankle arthritis involves a large, multi-site prospective clinical trial comparing the outcomes of patients who receive ankle fusion (arthrodesis) and patients who receive total joint replacement (arthroplasty). We are working with research groups from Seattle, WA; Grand Rapids, MI; Portland, OR; Edina, MN; and Fort Collins, CO. To date, 478 participants have enrolled in the study. We are comparing surgical outcomes by asking patients to complete research interviews before surgery and at 3, 6, 12, and 24 months after surgery. The interviews assess overall physical function, ankle-specific function, ankle pain intensity and interference with activities, and general health. The study also examines pre- and postoperative activity levels using a StepWatch Activity Monitor. Patients wear the monitor for up to 14 days before surgery and at 6, 12, and 24 months after surgery. Recruitment and follow-up are ongoing; we expect to enroll over 500 participants by the end of the enrollment period in 2015.
• Preventing limb loss is a major focus of our Center’s research. In the last year, we have completed a longtime collaboration with the Seattle Diabetic Foot Study that explored the relationship between plantar pressure and ulcer development. Our study, published in the Journal of Diabetes and Its Complications in November 2013, showed prospectively that baseline plantar pressure at a specific location is not predictive of ulcer occurrence at that location. However, when we analyzed the metatarsal heads separately, we found that subjects who ulcerated had higher baseline plantar pressure. This research demonstrated that pressure and plantar location have a complex relationship that clinicians must carefully consider; patients with high pressure beneath the metatarsals should be monitored closely.
• Over the last 5 years, our Center has developed a biplane fluoroscopy system for studying foot and ankle kinematics. This system uses an a priori computed tomography (CT) scan and dual X-rays to accurately and precisely track the motion of the bones of the foot. Sub-millimeter and sub-degree errors have been demonstrated in careful validation studies. We have begun to use the biplane system to better understand the implications of foot reconstructive surgeries for both severe flat feet and severe high arched feet.
• Our team has developed several new prosthetic limbs intended to improve the ability of lower limb amputees to walk on unpredictable terrain and maneuver in an architecturally-constrained environment. Existing, commercially-available prostheses provide a very narrow range of coronal and transverse plane stiffnesses, and once prescribed, cannot be adjusted. We have constructed two prototype prostheses in which either the coronal or transverse plane stiffness can be controlled over a wide range of values while worn by the amputee. Veteran amputees have walked on these prototype limbs in the laboratory environment, and we are using the lessons learned to improve the devices so they can wear them at home. To protect VA intellectual property and encourage commercial licensing, we have filed disclosure documents that have resulted in a US Provisional Patent.
• Many Veteran lower limb amputees complain about the accumulation of sweat inside their prosthesis. To address this comfort-related quality of life problem, we have built a novel prosthesis that expels perspiration. Our first field tests with five lower limb amputees have led to improvements in the design. With new Department of Defense funding, we are testing how well the improved device works under extreme environmental conditions (i.e., up to 95 °F). The results from these experiments, if the device works as well as we anticipate, are expected to lead to commercial partnerships and widespread implementation.
• Our team has completed the development of a novel single item mobility outcome measure (AMPSIMM) for use in quantifying mobility in dysvascular amputees. We have also completed an extensive psychometric analysis which reveals very strong psychometric properties including construct and predictive validity, responsiveness, and floor/ceiling effects. This novel measure will enhance the armamentarium of outcome measures available to clinicians and researchers because of its brevity, minimal caregiver and patient burden, and language that enables clear communication of functional mobility. The manuscript has been submitted to the Archives of Physical Medicine and Rehabilitation for review.

Key Services

• In July 2013, Dr. Bruce Sangeorzan assumed the role of Deputy Editor for The Journal of Bone and Joint Surgery, the world’s preeminent clinical orthopedic journal. The deputy editor is responsible for triaging, sending for review, and analyzing and editing manuscripts related to foot and ankle function, injury, deformity and salvage or reconstruction.
• Dr. Bruce Sangeorzan was named president-elect of the 2,100-member American Orthopaedic Foot & Ankle Society (AOFAS) in September 2014. His 12-month term will focus heavily on the strategic development of the AOFAS, whose members specialize in the diagnosis and treatment of disorders of the foot and ankle. In addition to serving on the AOFAS board for the last three years, he has participated in symposia, courses, and committees and presented research at the annual meetings. He has also previously won the prestigious AOFAS Roger A. Mann Award for Best Clinical Paper.
• Dr. William Ledoux serves on the executive board of the American Society of Biomechanics (ASB). He is the newsletter editor and is responsible for biannual newsletters, as well as the social media presence of the ASB both on Facebook and Twitter. The executive board meets biannually and is responsible for the governance of the largest biomechanics group in North America. He is also a member of the editorial board of the Department of Veterans Affairs Journal of Rehabilitation Research and Development, a premiere rehabilitation journal. Further, he serves on the editorial board of Foot and Ankle International, the preeminent orthopaedic foot and ankle journal and was recently asked to join the reconstituted editorial board of the Journal of Orthopaedic Research, considered one of the top 2 or 3 general orthopaedic journals.
• Our Center is a resource of expertise on the state-of-the-art of prostheses and the needs of lower limb amputees. Dr. Joseph Czerniecki demonstrates this through his service on the Scientific and Medical Advisory Committee (SciMAC) of the Amputee Coalition. His role on the SciMAC involves contributing clinical and scientific expertise for the development, implementation, and evaluation of programs, research, and policy initiatives. Because of his expertise, he was invited to participate in a consensus panel formed by the International Society of Prosthetics and Orthotics to develop International Clinical Practice Guidelines for the care of dysvascular amputees. He is also a member of the US Army Medical Research and Materiel Command (USAMRMC) Clinical and Rehabilitative Medicine Research Program’s (CRMRP) Scientific Steering Committee for Neuromusculoskeletal Research.
• Our Center provides expertise on review panels within the VA RR&D, DOD, and NIH. Drs. Czerniecki and Klute serve on the VA RR&D Research Career Scientist panel. Drs. Czerniecki, Klute and Ledoux serve on the VA RR&D Career Development Award panel. Dr. Ledoux serves as an ad-hoc reviewer for the RR&D Musculoskeletal/Orthopedic Rehabilitation panel and is an ad-hoc reviewer for the NIH National Institute of Nursing Research (NINR). Dr. Sangeorzan is an ad hoc reviewer for the NIH National Institute of Arthritis, Musculoskeletal and Skin (NIAMS) diseases panel. All of the investigators contribute to the review of manuscripts submitted for publication in a wide variety of engineering, biomechanics, and clinical journals.
• Our Center is a nationally-known training ground for the next generation of rehabilitation researchers. Nearly one hundred interested applicants pursue less than a dozen assistantships, fellowships, and internships within our Center. To highlight their work to the local community, our Center hosts a Young Investigator Symposium and organizes the Northwest Biomechanics Symposium to provide a nurturing environment where mentoring by Center Investigators can produce scholarship at the highest levels.
• Mr. Wesley Edmundson serves as the Western Division Administrative Officer Representative for the VA Field Research Advisory Committee (FRAC). In this role, he represents the interests of 15 VA hospitals in the western U.S. Through monthly meetings with the FRAC, he has helped identify issues of concern as well as critical barriers to success for the clinical and research arms of VA hospitals. In February 2014, after learning of shortfalls in IT funding and concerns about data storage capabilities for large research datasets, he surveyed the IT funding needs of six VA hospitals in the West. His report has received numerous compliments from stakeholders and laid the groundwork for future progress in this area.

External Advisory Board Members

External Advisory Board Overview

The Center’s external advisory board consists of clinical and research leaders from our local VA and the University of Washington. As a Center we are privileged to have an advisory board that provides an incredible base of experience in research, research administration and clinical practice. The current advisory board consists of: Edward Boyko, MD, MPH, Professor of Medicine, University of Washington, who has a long history of investigation into diabetes and its effect on foot ulceration and amputation, as well as obesity and its relationship to co-morbidities in diabetes; Howard Chizeck, PhD, Professor, Electrical Engineering, University of Washington, whose expertise lies in the area of control engineering theory and its application to biomedical problems; David Eyre PhD, Professor, Orthopaedics and Sports Medicine, University of Washington who has extensive research expertise in the development and treatment of bone and cartilage diseases (e.g., arthritis, osteoporosis); Sigvard T. Hansen, MD, Professor, Orthopaedics and Sports Medicine, University of Washington, who has an international reputation as a foot ankle surgeon; Fredrick A. Matson, III, MD, Professor, Orthopaedics and Sports Medicine, University of Washington, whose expertise is in the area of identifying better approaches to restoring comfort and function to joints damaged by arthritis, injury, or surgery; and Lawrence Robinson, MD, Vice Dean of Clinical Affairs and Graduate Medical Education and Professor, Rehabilitation Medicine, University of Washington. The advisory board meets annually with the Center leadership and executive committee to review the programmatic function, funding, research priorities and directions of the Center. Through this mechanism they have an opportunity to provide critical input regarding operational issues of the research center and to provide input on specific research programs that align with their areas of expertise. This fiscal year the meeting was held virtually on March 7, 2013.

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