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.