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Research Advances Have Enormously Improved Hip Repair

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Duke Health News 919-660-1306

The hip replacement surgery of Duke basketball coach Mike
Krzyzewski has emphasized the critical role of clinical and
basic research in the rapid advance of the surgery since its
development in the 1960's.

Current research includes efforts to improve the materials
and design of the hip joint prostheses, and even to avoid the
surgery by rejuvenating deteriorating hip joint bone and
cartilage.

For example, at Duke University Medical Center, Associate
Professor of Surgery Thomas Parker Vail, with funding by the
National Institutes of Health (NIH), is studying new implant
designs -- including more flexible hip stems and improved
plastics and ceramics for bearing surfaces. Vail and his
colleagues also are exploring the clinical effects of bone
compaction and the use of smaller, more conservative incisions
for hip replacements. And the physicians are conducting
clinical trials to evaluate cemented and cementless implant
designs and methods to prevent surgical complications.

In a pioneering advance that enables young people to avoid
hip replacement, Dr. James Urbaniak, Duke medical center chief
of orthopedic surgery, has developed techniques to surgically
implant new bone to rejuvenate deteriorating hip joints.

The process, called free vascularized fibular graft,
involves transplanting a short length of the fibula, the
smaller of the two leg bones, into a hole drilled up into the
center of the ball of the hip joint. Surgeons then pack the
space around the bone graft with bone shavings and route a
blood vessel into the graft to nourish new bone growth.

In NIH-funded clinical trials, Urbaniak and his colleagues
have performed some 1,300 of the implant operations on patients
with osteonecrosis, or dying bone, restoring a healthy joint in
more than 80 percent of cases.

Growing new cartilage to help restore hip and other joints,
reducing the need for replacement surgery, is the objective of
other promising federally funded basic research.

For example, Duke research includes efforts to measure the
basic mechanical and chemical factors that affect cartilage
growth. In research sponsored by the National Science
Foundation and the NIH, Assistant Professor of Orthopedic
Surgery Farshid Guilak is working with colleagues including
Lori Setton, assistant professor of biomedical engineering in
the Center for Cellular and Biosurface Engineering, to
understand the mechanical forces that cartilage cells, called
chondrocytes, undergo in the spinal cord and other joints.

And Associate Professor of Orthopedic Surgery Sean Scully is
exploring the chemical signals that trigger chondrocytes to
divide and to synthesize the matrix that makes up
cartilage.

Such research advances in treating joint disease have
depended critically on adequate research funding -- both
internal institutional research funds and federal basic
research funds -- emphasized Dr. Ralph Snyderman, chancellor
for health affairs at Duke.

"Internal institutional research support at Duke has played
an essential role in funding clinical research that has
improved hip prostheses materials and designs to the point
where they last for decades," Snyderman said.

"Such institutional support is critical to enable medical
researchers to explore revolutionary ideas that can lead to
important clinical advances. This internal support also
provides seed funding that can attract additional federal
grants, as well as help launch the careers of promising new
faculty who will make important future advances in treating
disease."

Despite the importance of such internal resources, Snyderman
emphasized that academic health centers are having great
difficulty maintaining research funding levels.

"The current highly competitive managed care market is
endangering the ability of academic health centers to continue
to provide that support to their researchers," he said.

Snyderman cited, for example, a survey of 2,000 medical
school faculty reported in the March 24-31 Journal of the
American Medical Association, that showed that academic health
centers in highly competitive health care markets devoted a
smaller portion of their budgets to institutional research
support.

The survey, by researchers at Massachusetts General Hospital
and Harvard Medical School, found that the amount of
institutional support as a proportion of total funding was more
than twice as high in less competitive markets (6.1 percent)
compared with the most competitive markets (2.5 percent).

"Certainly, academic health centers must make every effort
to remain competitive, which is why Duke has created a
comprehensive Duke University Health System," Snyderman said.
"However, the critical role of internal research funding must
be recognized in developing federal policies for supporting
academic health centers."

Also, despite recent increases in federal funding, this
important source of research support remains inadequate,
Snyderman warned.

"Future advances in hip replacement surgery and in treatment
of bone disease depend critically on basic and clinical
research funding by such agencies as the National Science
Foundation and the National Institutes of Health," he
emphasized.

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