Brian Hafner, Ph.D. & Doug Smith, M.D.
Prosthetics Research Study (PRS), Seattle, WA
"Osseointegrated prosthetic limbs: challenges in next-generation prosthetic design"


ABSTRACT

Recovery from a transfemoral (or above-knee) amputation is a long and complex process, often producing less-than-desirable results.  Even a "successful" rehabilitation often involves complications such as residual limb skin breakdown, pain, and poor control of the prosthetic limb.  These problems are often amplified for those amputees with very short residual limbs or those with non load-tolerant skin.  A proposed solution to such difficulties is the use of "osseointegration," or direct skeletal attachment, to connect the prosthetic limb directly to the residual femur. 

While this osseointegration technique has been successful in a small number of candidates, there remain several significant challenges in the long-term acceptance of an osseointegrated, lower-limb prosthesis.  Biomechanically, the success of an osseointegrated prosthesis is highly dependent upon integration of both a bone-implant interface and a skin-implant interface.  Furthermore, osseointegrated prostheses produce abnormal gait patterns, require strict adherence to hygiene regimens, and limit amputee activity to lower-impact levels.  However, successful patients reap the rewards of reduced residual limb skin problems, simplified prosthesis donning and doffing, and increased perception of the prosthetic limb (termed "osseoperception").

Despite the advantages offered by an osseointegrated prosthetic limb, there remain significant challenges to the success of this system.  These are personal, clinical, and biomechanical in nature and require the efforts of the amputee, the surgeon, the bioengineer, and the rehabilitation team to overcome.  We will present a brief history of osseointegration, illustrate the current device and medical procedure for transfemoral prosthetic limbs, and discuss the current limitations and key challenges in furthering the development of this technology."

Dr. Hafner is a 2003 graduate of the University of Washington Bioengineering Department.  His research activities included mathematical modeling and clinical gait analysis of transtibial (below-knee) amputees in bouncing gait.  Dr. Hafner is a research engineer for Prosthetics Research Study (PRS), a Seattle non-profit corporation specializing in amputee education, charity care, and research.

Dr. Smith is an Associate Professor of Orthopedic Surgery at the University of Washington, the Director of Prosthetics Research Study, and the Medical Director of the Amputee Coalition of America (ACA).  He also runs the amputee clinic at Harborview Medical Center Trauma Center.