CONTACT: CLANCY CHAMPANOIS
Joint Office for Planning, Marketing and Communications
8798 John Pappajohn Pavilion
Iowa City IA 52242
Release: Oct. 24, 2002
Photo: Nicole M. Grosland, left; Brian D. Adams
New total wrist replacement device created at UI Orthopaedic Biomechanics
of Iowa Health Care researchers, working with San Diego-based biotechnology
company Kinetikos Medical, Inc. (KMI), have developed a new total wrist prosthesis
for patients with severe wrist arthritis. The Universal 2 total wrist system,
developed by Brian D. Adams, M.D., professor of orthopaedic surgery, and Nicole
M. Grosland, Ph.D., assistant professor of biomedical engineering and orthopaedic
surgery, was designed at the UI Orthopaedic Biomechanics Laboratory.
Although attempts at total wrist replacement have historically been fraught
with complications, early indications are that the Universal 2's unique design,
which closely mimics the normal wrist anatomy, will overcome past obstacles.
The prosthesis, which uses the same materials and some of the same mechanical
concepts as in total hip and total knee replacement, is engineered for both
performance and longevity.
"The best patient for the Universal 2 prosthesis is an individual with
severe wrist arthritis who is not routinely involved in activities that place
high demands on the hand and wrist," said Adams, who performs between
15 and 20 wrist replacements per year.
Since the Universal 2 device was cleared to market by the FDA earlier this
year, approximately 30 of the new prostheses have been implanted.
"The long-term prognosis for these patients is excellent for both function
and durability," Adams said.
Each phase of development of the Universal 2 included both laboratory testing
and computer modeling. This work was completed in the UI Orthopaedic Biomechanics
Lab, which has been actively involved in research of the hand and wrist and
the development of implants since the 1960s. The research team consists of
faculty and professional engineers who work collaboratively with faculty orthopaedic
"The computer model allowed information to be gathered that is not
readily available through experimental testing alone," Grosland said.
"For example, the model depicted how the components move relative to
each other, how loads transfer through the prosthesis and into the surrounding
bone, and how the materials may deform under high stress."
Laboratory experiments were used to test motion at the articulating surfaces
to determine the strength of the connections between the plastic and metal
parts and to assess the durability of the metal stems that fix into the bone.
Adams and his colleagues evaluated other wrist replacement devices in developing
their new design.
"Our first goal was to improve the shapes of the articulating surfaces.
By changing these shapes, stresses on bone and the prosthesis, as well as
the risk of dislocation, were greatly reduced," he said.
Additional enhancements in the Universal 2 include the option to implant
the prosthesis without cement when indicated by the physician, preservation
of more bone, an offset position of the prosthesis within the bone to increase
wrist motion and power, and precise instrumentation for accurate insertion
of the prosthesis.
University of Iowa Health Care describes the partnership between the UI Roy
J. and Lucille A. Carver College of Medicine and UI Hospitals and Clinics
and the patient care, medical education and research programs and services
they provide. Visit UI Health Care online at www.uihealthcare.com.