Total Hip Arthroplasty
Every year approximately 200,000 hip replacement surgeries are
performed in the United States and the success rate appears to
be about 90 percent. The most common reason for hip
replacement is osteoarthritis of the hip joint; however,
surgery is not a “quick fix” for every person with chronic hip
pain. Surgery, in this instance is used only after medication
and other, less-aggressive treatments have failed.
More than 21 million people in the United States have
degenerative osteoarthritis, and it is the leading cause of
chronic disability. The number of arthritis related hospital
admissions doubled between 1993 and 2006.
Most people undergo hip replacement as a result of
osteoarthritis of the hip joint. But you might also consider
hip replacement if you experience severe pain, loss of motion
or deformity of your hip joint. Hip replacement is also used
in people with hip injuries, rheumatoid arthritis, impaired
nerves, loss of muscle strength surrounding the joint, and
other medical conditions, such as a bone tumor or bone loss
due to insufficient blood supply (avascular necrosis).
Symptoms that may lead to the decision to undergo hip
replacement include severe pain and loss of motion or
stiffness in the joint. Pain that keeps you awake at night,
little or no relief from pain medications, difficulty walking
up or down stairs, trouble standing from a seated position, or
having to stop activities because of pain are additional
considerations that can lead to interference in everyday
living.
Today’s hip prosthetics can be expected to last up to 20
years. Usually hip replacement has been an option for adults
older than age 60. Because the newer technology has brought
about stronger and longer lasting artificial joints, younger
and more active people are choosing this surgery.
Hip replacement may be the only choice after failure of other
less invasive therapy fails to relive increasing pain. While
hip replacement, or total hip arthroplasty, can relieve pain
and improve range of motion, it is not without risk.
The current rate of obesity is of major concern to surgeons
who provide this type of orthopedic surgery. Only recently has
this data been made available through the Mayo Clinic.
Researchers have found that there is a 50 percent increase in
complications when obesity and super obesity is present. In
order to be considered a “best candidate” for hip replacement
surgery, there must first be significant joint and cartilage
damage shown on X-ray, severe and deep pain, no relief from
medication for pain and inflammation, and interference in
daily activities of living.
Usually if a patient has disabling heart disease, uncontrolled
high blood pressure, infection or very poor overall health,
this surgery will not be scheduled.
Currently either metal-metal or ceramic-metal hip prostheses
are used in replacement surgery.
A third type of prosthetic hip joint was in use from 2003
until 2008. In July 2008, the “Zimmer
Durom Acetabular Cup,” a metal-polyethylene prosthetic
device, was removed from the market. At that time the
manufacturer began a significant effort to provide new
training to orthopedic and general surgeons and began to
develop new educational support materials.
Considered by surgeons for at least 30 years to be highly
durable, the Metal-on-Polyethylene prostheses had been the
leading artificial hip component material and had been
approved.
The
Zimmer Durom hip replacement device is made with a cobalt
chrome molybdenum alloy metal ball with a polyethylene liner.
Polyethylene is the most understood and had been the most used
of all liner materials, which offered surgeons a range of
stability options while the operation was underway.
The ability of polyethylene to be adaptively customized during
surgery is considered important; however it is the least
expensive bearing.
Since all implants, including the
Zimmer Durom hip implant device, are subject to wear and
tear, they shed debris. After about 10 to 15 years of use the
debris shows up with symptoms of inflammation and bone loss.
The wear rate of Metal-on-Polyethylene implants, such as the
Zimmer Durom hip replacement device, is about 0.1 millimeters
a year.
To overcome the issue of “debris” manufacturers chose to treat
the polyethylene liners with radiation to create new wear
resistant polyethylene. This new substance is called “highly
cross linked polyethylene.”
In July 2008, after reviewing data on more than 3,000 cases,
Zimmer, the world's largest manufacturer of hip replacement
parts, suspended sales of the Zimmer Durom Acetabular
Component (Durom Cup).
The Indiana-based manufacturer states that it was unaware of
any design or manufacturing defects and a Zimmer Durom hip
recall was not issued. Zimmer has plans to place the Durom Cup
back on the market on completion of its training and education
projects.
Several
Zimmer Durom hip implant lawsuits have been filed against
Zimmer Holdings Inc., claiming it failed to provide proper
warnings, instructions and training to surgeons.
In early 2008, one prominent orthopedic surgeon wrote openly
about problems he experienced with
Zimmer Durom hip replacements. His data showed that out of
165 implants, 14 were "revised or required revision" within
the first two years after surgery. The surgeon added that he
believed the Zimmer Durom hip replacement device was defective
and there were seating problems with the surface where
fixation in the natural joint was to occur.
Zimmer advised that people who have received the Durom Cup to
contact their doctor if they experience pain more than three
months after surgery.
This article is part of a consumer health education series
written by Gayle Eversole, DHom, PhD, MH, NP, ND, of Creating
Health Institute, in collaboration with
Bernstein Liebhard, LLP.
The views expressed in this article are solely those of the
author, Gayle Eversole.
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