Knee
> Arthritis
> Treatments
Unicompartmental
Knee Replacement
Preparing for Surgery
The decisions you make and the actions you take
before your surgery can be every bit as important as the
procedure itself in ensuring a healthy recovery. Getting
a second opinion from a surgeon who is as qualified as
the surgeon who gave the initial diagnosis is usually
recommended.
Make
sure you have received any equipment you will need when
you get home from the hospital. This may include a knee
brace, crutches, ice packs or coolers, or a continuous
passive motion (CPM) machine. You should receive prescriptions
for any of these from your doctor when your surgery
is scheduled.
Understand
the potential risks and benefits of the surgery, and
ask your surgeon any questions that will help you better
understand the procedure. It can also help to talk to
someone else who has undergone the same surgery.
Before
surgery, notify your physician of any physical problems
you have been experiencing, such as a fever or infection.
You should also notify your surgeon of any medication
you are taking.
Practice
walking with your crutches in case you need to use them
after surgery.
Make
sure the orthopedist performing the surgery is board-certified,
which can be determined by calling the American Board
of Orthopaedic Surgery at 919-929-7103.
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What
to ask the doctor
What
to take to the hospital
At most medical centers, you will go to "patient
admissions" to check in for your outpatient arthroscopic
surgery. After you have checked in to the hospital or
clinic, you will go to a holding area where the final
preparations are made. The paperwork is completed and
your knee area may be shaved (this is not always necessary).
You will wear a hospital gown and remove all of your
jewelry. You will meet the anesthesiologist or anesthetist
(a nurse who has done graduate training to provide anesthesia
under the supervision of an anesthesiologist). Then,
you will walk or ride on a stretcher to the operating
room. Most patients are not sedated until they go into
the operating room. Here are some important steps to
remember for the day of your surgery:
You
will probably be told not to eat or drink anything after
midnight on the night before your surgery. This will
reduce the risk of vomiting while you are under general
anesthesia.
Since
you will most likely be able to go home within a few
hours of surgery, and because the anesthetic and pain
medications may make you drowsy, arrange for someone
to drive you home when you are released.
Wear
a loose pair of shorts or sweatpants that will fit comfortably
over your knee bandage when you leave the hospital.
Take
it easy. Keeping a good frame of mind can help ease
any nerves or anxiety about undergoing surgery. Distractions
such as reading, watching television, chatting with
visitors, or talking on the telephone can also help.
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ABC’s
of anesthesia
What
to take to the hospital
During a unicompartmental knee replacement, surgeons
reshape bones on one side of your knee. Metal and polyethylene
components that mimic the shape and function of a normal
knee are then attached to the ends of your shinbone
and thighbone. The procedure usually takes about one-and-a-half
hours to perform. A unicompartmental knee replacement
requires the removal of about a quarter inch of bone,
compared to the half-inch required for a total knee
replacement. A total knee replacement can still be performed
in the future if arthritis damages the other side of
your knee.
SURGERY
After
anesthesia is administered, which may be regional, or
general, the surgical team sterilizes the leg with antibacterial
solution.
One
to three small, four-millimeter incisions may be used
for the diagnostic portion of the operation. Surgeons
can take a close look at your knee with the aid of an
arthroscope (a tiny camera about 3.5 millimeters in
diameter).
A
three-inch incision is made down the front of the knee,
exposing the ends of the shinbone and thighbone.
Rough
areas of arthritic cartilage covering the ends of the
bones are smoothed or repaired.
On
the damaged side of your knee, a quarter-inch piece
of bone is removed from the bottom of your thighbone
to expose the top of your shinbone.
Damaged
cartilage and meniscus (the main cartilage pad in the
center of your knee) are removed from the top of the
shinbone on one side of your knee.
The
top of your shinbone is flattened and reshaped to fit
the prosthetic shinbone part. The plastic shinbone component
is cemented in place.
The
damaged area on the bottom of your thighbone is removed
and reshaped to fit the metal thighbone part. The metal
piece is cemented in place over the thighbone.
Surgeons
test the function of the new prosthetic pieces by bending
the knee.
The
layers of tissue in your knee are stitched together
and you are taken to the recovery room.
Following a unicompartmental knee replacement, you
usually stay in the recovery room for at least two hours
while the anesthetic wears off. You will be given pain
medicine, either orally or through an IV (intravenous)
line, as well as instructions for what to do over the
next couple of days. Your knee will be bandaged and
may have ice on it. You may have significant pain early
on and you should take the pain medicine as directed.
Remember that it is easier to keep pain suppressed than
it is to treat pain once it becomes present, so ask
the nurse for medication when you feel pain coming on.
You should try to move your feet and ankles while you
are in the recovery room to improve circulation. Your
temperature, blood pressure, and heartbeat will be monitored
by a nurse, who, with the assistance of the doctor,
will determine when you are ready to leave the hospital
or, if necessary, be admitted for an overnight stay.
Most patients remain in the hospital for one or two
nights following a unicompartmental knee replacement.
After a unicompartmental knee replacement, you usually
are taken to a hospital room where the medical staff
can regularly monitor your recovery. To prevent the
knee joint from stiffening after surgery, your operative
knee will be placed in a continuous passive motion (CPM)
machine. The CPM machine is attached to your bed, and
moves your knee through a continuous range of motion.
There will likely be pain, and you can expect to be
given pain medication as needed. Ice also helps control
pain and swelling. If you have a heart condition, you
may be taken to the ICU (intensive care unit) for routine
cardiac monitoring. For two or three days after surgery,
you may experience night sweats and a fever of up to
101. Your physician may suggest acetaminophen, coughing,
and deep breathing to get over this. This is common
and should not alarm you. You will be given a prescription
for pain medication and schedule a series of follow-up
visits sometime around one week, one month, and three
months after surgery. The incision usually starts to
close within six days and the bandage can be removed.
Physicians commonly fit you with a hinged knee brace
that allows a limited range of movement. You may be
able to bear weight on your knee when released from
the hospital. But some patients may need to use crutches
for a few weeks until they are comfortable walking on
their new knee. Your physician and physical therapist
will help you learn to balance on the new knee and let
you practice unaided walking and going up and down stairs
before you leave the hospital.
You may feel pain or discomfort for the first week at
home after a unicompartmental knee replacement, and
you will be given a combination of pain medications
as needed. A prescription-strength painkiller is usually
prescribed and should be taken as directed on the bottle.
Taking one every four to six hours as directed is a
good idea during the first few days to suppress pain.
Swelling in your knee usually slowly decreases over
a span of two to three weeks after surgery. There may
be some minor bleeding for a few days, but by the time
you are released from the hospital, most bleeding should
have stopped. If you notice swelling or bleeding increase,
you should call your physician. Physicians generally
recommend that you avoid activities that place stress
your knee for about two weeks, so that the bones and
cartilage can heal around the implant. Light walking
and stretching can usually start immediately after surgery.
Here is what you can expect and how you can cope after
an unicompartmental knee replacement:
Icing
your knee for 20 or 30 minutes a few times a day during
the first week after surgery will help reduce pain.
Keep
your knee elevated above heart level as much as possible
to reduce swelling and pain. Place pillows under the
ankle of the operative leg while you are in bed.
Immobilize
your knee in the prescribed, hinged knee brace for about
two weeks. You may remove the brace for brief periods
to perform passive motion exercises with the aid of
a physical therapist or a CPM machine. Range of motion
exercises are important for healing. Regaining full
extension is just as important as bending your knee.
To
help speed healing, keep your incision dry for seven
to ten days. A plastic shower bag can help keep the
incision dry while bathing. You can purchase these bags
at a pharmacy or surgical supply store. Wait until you
can stand comfortably for 10 or 15 minutes at a time
before you take a shower without assistance.
Crutches
or a cane may be needed for about two weeks, depending
on the pain. Older patients may have to continue using
crutches or a cane for a longer period of time.
Most patients can resume normal daily activities, driving,
and light exercise, like swimming and cycling, within
two weeks after surgery.
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Recovery-proof
your home
When
to call the doctor after surgery
Most patients can begin physical therapy immediately
after surgery. In the first few weeks of rehabilitation,
your physical therapist usually helps you stretch the
muscles in your hamstrings, quadriceps, and calves while
flexing and extending your knee to restore a full, pain-free
range of motion.
AEROBIC EXERCISE
When pain has decreased, physicians generally recommend
at least 30 minutes of low-impact exercise a day for
patients with arthritis. You should try to cut back
on activities that place added stress on your knees,
like running and strenuous weight lifting. Cross-training
exercise programs are commonly prescribed when you have
arthritis. Depending on your preferences, your workouts
may vary each day between cycling, cross-country skiing
machines, elliptical training machines, swimming, and
other low-impact cardiovascular exercises. Walking is
usually better for arthritic knees than running, and
many patients prefer swimming, which takes your body
weight off your knees and makes movement easier. Once
your physical therapist has taught you a proper exercise
program, it is important to find time each day to perform
the prescribed exercises.
STRENGTHENING
Strength training usually focuses on moving light weights
through a complete, controlled range of motion. You
should generally avoid trying to lift as much as possible
with your quadriceps and hamstrings. Your physical therapist
typically teaches you to move slowly through the entire
movement, like bending and straightening your knee,
with enough resistance to work your muscles without
stressing the bones in your knee. Once your physical
therapist has taught you a proper exercise program,
it is important to find time each day to perform the
prescribed exercises.
RELATED TOPICS
Knee
strengthening exercises: Cartilage injuries
Most prosthetic knees can last for over twenty years
if you are careful to avoid injury and overuse. After
rehabilitation, preventing osteoarthritis is a process
of slowing the progression and spread of the disease.
Because patients remain at risk for continued pain in
their knees after treatment, it is important they are
proactive in managing their conditions. Maintaining
aerobic cardiovascular fitness has been an effective
method for preventing the progression of osteoarthritis.
Light, daily exercise is much better for an arthritic
knee than occasional, heavy exercise. When you have
arthritis in your knees, it is especially important
to avoid suffering any serious knee injuries, like torn
ligaments or fractured bones, because arthritis can
complicate knee injury treatment. You should avoid high-impact
or repetitive stress sports, like football and distance
running, that commonly cause severe knee injuries. Depending
on the severity of your arthritis, your physician may
also recommend limiting your participation in sports
that involve sprinting, twisting, or jumping. Because
osteoarthritis has multiple causes and may be related
to genetic factors, no simple prevention tactic will
help everyone avoid increased arthritic pain. To prevent
the spread of arthritis, physicians generally recommend
that you take the following precautions:
Avoid
anything that makes pain last for over an hour or two.
Perform
controlled range of motion activities that do not overload
the joint.
Avoid
heavy impact on the knees during everyday and athletic
activities.
Gently
strengthen the muscles in your thigh and lower leg to
help protect the bones and cartilage in your knee.
Non-contact activities are a great way to keeping joints
and bones healthy and maintain fitness over time. Exercise
also helps promote weight loss, which can take stress
off your knees.
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