|
Mike Rowlison - Oxford Partial
Knee
Partial artsImplant leaves much of ‘native
knee' intact, gains faith as long-term solution By Michael
Schroeder
Link
http://www.journalgazette.net/apps/pbcs.dll/article?AID=/20080330/BIZ/803300410
Going back and forth between his office and the
deputy clerk’s office isn’t such a big deal anymore for Mike
Rowlison.
The 61-year-old clerk-treasurer of the town of LaGrange used to
limit his walking, especially taking the stairs, because of the pain
it caused. His knee problems started when he was in his early 50s,
but he found relief last month in the form of a partial knee
implant.
As the name implies, the surgery involved only part of Rowlison’s
knee – the inner, or medial, component targeted in most partial knee
procedures. Rowlison says he feels great and will probably to have
the same operation – which was done on his left knee – performed on
the right one in October.
As more people undergo knee replacement operations, many with
isolated damage are getting partial knee implants. The surgery is
used when a complete overhaul isn’t needed and promises quicker
recovery, less pain and less bone loss than a total knee
replacement.
Partial knee implants have been around for decades, but
technological advances and the introduction of improved implants in
the U.S. market have renewed enthusiasm for the option. Those
advances and long-term study results have tested traditional
thinking about the partial implant’s place as a short-term or
late-in-life fix. Many surgeons consider it a long-lasting option
for patients of all ages.
Surgeons vary in their use of partial implants and characterizations
of whom could benefit. The American Academy of Orthopaedic Surgeons
estimates 6 percent to 8 percent of patients with arthritic knees
are good candidates for the surgery. But many surgeons – including
some academy members who presented at the 75th annual academy
meeting this month in San Francisco – think the number is
considerably higher, one-third or more. That reflects more
aggressive use of partial knee implants outside the U.S.
Dr. Steven Fisher of Fort Wayne Orthopaedics operated on Rowlison in
February. Fisher implants the Oxford partial knee system made by
Warsaw-based Biomet Inc. in about half of all his surgical patients.
He’s bullish about the implant, owing to his personal experience and
studies showing its long-term effectiveness.
The system was first implanted more than 25 years ago but didn’t
gain approval in the U.S. until about four years ago. The most
commonly used partial knee implant is also the only fully
mobile-bearing partial knee system in the U.S., according to the
company. The implant uses a moveable plastic bearing to give
patients greater range of motion.
Numerous studies show success rates easily exceeding 90 percent
after 10 and 15 years, drawing comparisons to full knee
replacements. Surgeons say it’s more technically demanding to
implant – requiring special training – compared with fixed-bearing
partial knee systems that tend to perform slightly better in the
short term. But company officials say its long-term prowess is the
reason it’s leading the partial knee market.
Fisher, who has special training to implant the Oxford, thinks
opportunities in the partial knee market go far beyond what’s
currently realized. An estimated 49,400 partial knee implant
procedures were performed in the U.S. in 2006, less than 10 percent
of all primary knee implant surgeries, according to the latest
figures from Orthopedic Network News, an industry newsletter.
The market shows that most American surgeons are generally
conservative in their use of partial knee implants, despite the
successes of their colleagues who use the technology more liberally.
Dr. Michael Lee of Fort Wayne-based Orthopaedics Northeast says
about 10 percent of the knee surgeries he performs are partial knee
implants. Like Fisher, he uses the Oxford and acknowledges the
proportion of patients considered candidates for partial knee
implants varies greatly by surgeon, depending on that surgeon’s
philosophy, training and other factors.
Overall, success with partial knee implants is highly dependent on
proper patient selection, Lee said. He considers the surgery for
patients with arthritis fairly isolated in the medial compartment of
their knee, but he doesn’t follow all traditional criteria.
The American Academy of Orthopaedic Surgeons says a partial knee
replacement “is best suited for the older, slim person with a
relatively sedentary lifestyle.” But Lee and others in the field
aren’t opposed to partial knee implants for demographics including
younger patients. With a partial implant, the patient retains more
bone and might be able to delay or avoid full knee replacement, he
said.
“It feels more like a normal knee to patients” because much of the
“native knee” is still intact, Lee said.
But conserving bone isn’t limited to knee implants.
“Overall, with joint replacement, bone conservation is where the
market is going,” said Scott Ellison, a large-joints analyst with
PearlDiver Technologies Inc., a Fort Wayne-based orthopedic data
firm. “It fits right in with the trend we’re seeing with hips.”
First approved for the U.S. market in 2006, hip resurfacing
technology provides some patients an alternative to total hip
replacement. With hip resurfacing, only the surface of the hip ball,
or femoral head, is removed; it’s then capped by smooth metal.
Warsaw’s Orthopedic Big Three – Biomet, Zimmer Holdings Inc. and
DePuy Orthopaedics Inc. – are working to get FDA approval to market
hip resurfacing technologies. DePuy got pre-market approval in
September, one of the first steps in the regulatory approval
process. Company officials declined to speculate when it might get
final FDA approval, but at least one competitor thought DePuy would
be the first of the Big Three to bring its hip resurfacing
technology to market.
Meanwhile, local advances continue to be made in partial knee
technology.
A new partial knee system developed by a Warsaw-based startup is
expected to be out the third quarter of this year. It’s the only
partial knee implant FDA-approved for use with arthroscopic surgery
(which employs a tiny camera to show the inside of a joint on a TV
monitor), according to Dr. Ron Clark, founder and chairman of VOT
Arthroscopic Solutions.
The South Bend-based surgeon developed the Solo partial knee system,
which requires a 1-inch incision to be implanted. Traditional
partial knee replacement surgery requires a 3- to 5-inch incision.
Clark expects good things for Solo and the partial knee implant
market in general. Successes in the sector are driving a growing
market, he said.
|
|