Active baby boomers consider knee
and hip replacements... well, hip
Those under 55 are replacing joints
at an unprecedented rate.
Will they outlive their artificial parts?
BY JANET BAINE
NIH confirms effectiveness
of total knee replacement, but more study is needed
BY MAIRI McKINNON
More than 20 years
of research show that, for most people suffering
from severe knee pain and disability that doesn't
respond to nonsurgical therapies, total knee replacement
(TKR) is a safe, cost-effective treatment for
restoring physical function and mobility and relieving
discomfort.
Despite advances in
TKR technology since its first use in the late
1950s, questions remain about which materials,
implant designs and surgical approach give the
best outcome for specific patient groups. Surgical
technique, choice of prosthesis as well as volume
of procedures performed by the surgeon and hospital
affect both short- and long-term success. Skill
appears to increase the more the technique is
done. Other factors that contribute to positive
outcomes are pre- and postoperative risk assessment,
antibiotic prophylaxis, pain management and treatment
of medical conditions.
While knee prostheses
are generally durable, revisions are sometimes
necessary, especially due to loosening of the
prosthesis. Patient risk factors include age younger
than 55, male gender, diagnosis of osteoarthritis,
obesity and presence of comorbid conditions.
Clear evidence exists
for racial, ethnic and gender differences in the
provision of TKR, but the reasons aren't well
understood. Patients' mistrust of the healthcare
system and lack of familiarity with the procedure,
and physicians' beliefs about patients may each
play a role. These are among the findings of a
recent consensus report. The final version of
the panel's statement will be available at www.consensus.nih.gov.
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When her doctor saw the condition
of Janet Wright-Smit's joints he didn't hesitate to
recommend a knee replacement. The operation on one knee
was done last March. A second is scheduled for early
this month.
It was "pretty traumatic,"
says Ms Wright-Smit, but she would "strongly encourage
someone to face and embrace" joint replacement surgery.
At age 57, she is one of a growing number of baby boomers
getting new hips and knees at an earlier age than their
parents did.
Although 70% of these procedures
in Canada are performed on people 65 years of age and
older, the 45-54 age group experienced an increase of
90% for knee and 30% for hip replacement, according
to a report on joint replacement compiled using information
from the Canadian Joint Replacement Registry (CJRR)
that was released by the Canadian Institute for Health
Information (CIHI).
The risk of surgery was worth
taking for nurse Wright-Smit, who lives in Guelph, Ont.
She lived an active life until seven years ago when
arthritis and chronic fatigue syndrome forced her to
stop working as a nurse and eventually landed her in
a wheelchair. One knee
was replaced last April and she expects the second to
be done this month.
Liberating
operation
"It is amazing how
liberating this is and I feel grateful and blessed to
live in Canada," she says. Osteoarthritis runs in her
family. She recalls that her grandmother could do little
more than move between her bed and rocking chair and
kept a bottle of what her grandchildren were told was
lemon juice at her side. It was actually alcohol, the
only way she had of coping with the pain.
"Total hip and knee replacements
traditionally have depended on a metal-plastic articulation
which wears and creates minute particles which stimulate
bone resorption," says Dr Robert Bourne, an orthopedic
surgeon at the London Health Sciences Centre in London,
Ont and Chair of the CJRR advisory. This is particularly
worrisome in young, active patients, but there are many
new technologies emerging that look promising to keep
younger patients on the ski hills and golf courses.
"These include ceramics,
metal-on-metal, oxidized zirconium metal and cross-linked
polyethylenes, which seem promising in allowing total
joint replacements in younger people," Dr
Bourne says. He also points out that few long-term studies
are available, and the CJRR will
gather more data to help health professionals know which
patients do best, which surgical techniques work best
and which implants provide the most durable results,
requiring less revision. It will also keep track of
the waiting period and the impact this has on the results
of surgery.
Sweden is leading the way
in collecting data, with a joint registry that was started
in the 1970s. At that time, revision rates were about
what they are today in North America, but now the Swedish
revision rates have been cut in half.
Revision
surgery
The cost of hip or
knee replacement is about $10,000 and the revision is
a more difficult surgery.
"The results are not as good
as after a first-time knee replacement," says Dr Nazir
Mohamed, an orthopedic surgeon at the Toronto Western
Hospital and Chair
of the Research Committee for the Ontario Joint Replacement
Registry. "There is the potential at some point that
the joint may not be reconstructable, therefore in very
young individuals we try to defer doing joint replacement
surgery until they are older so that the number of revisions
they may require in their lifetime is no more than one
or two."
The age group getting joint
replacement surgery will get younger as technology,
information and experience with implants increases,
according to the doctor. Joint replacements are expected
to double over the next two decades as the population
ages.
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