Knee joint replacement
Definition
Knee joint replacement is surgery
to replace a knee joint with an artificial joint. The artificial
joint is called a prosthesis.
Alternative Names
Total knee replacement; Knee
arthroplasty; Knee replacement - total; Tricompartmental knee
replacement
Description
You may receive general anesthesia before this surgery. This means
you will be unconscious and unable to feel pain. Or, you may have a
spinal or epidural anesthesia. In this kind of anesthesia, medicine
is put into your back to make you numb below your waist.
After you receive anesthesia,
your surgeon will make an incision (cut) over your knee to open it
up. Then your surgeon will:
- Move your kneecap (patella) out
of the way, then shape the ends of your thigh bone and shin bone to
fit the prosthesis. Your surgeon will also cut the underside of
your kneecap to prepare it for the artificial pieces that will be
attached there.
- Fasten the two parts of the
prosthesis to your bones. One part will be attached to the end of
your thigh bone and the other part will be attached to your shin
bone. Both parts will then be attached to the underside of your
kneecap. Your surgeon will use a special bone cement to attach
these parts.
Usually, artificial knees have
metal parts. Now, though, some surgeons are using some different
materials, including metal on metal, ceramic on ceramic, or ceramic
on plastic.
Why the Procedure Is Performed
Knee joint replacement may be
recommended for:
- Severe arthritis (osteoarthritis
or rheumatoid arthritis) of the knee that has not gotten better
with medicine, injections, and physical therapy after 6 months or
more of treatment. Your doctor may recommend knee replacement for
these problems:
- Inability to sleep through the
night because of knee pain
- Knee pain that has not improved
with other treatment
- Knee pain that limits or keeps
you from being able to do your normal activities, especially your
daily activities such as bathing, preparing meals, household
chores, and other things.
- Some tumors that affect the
knee
Even when a knee replacement is
needed, some medical problems may lead your doctor to recommend
that you not have it done. Some of these problems are:
- A knee infection
- Morbid obesity (weighing over
300 pounds)
- Very weak quadriceps, the
muscles in the front of your thigh. Weak quadriceps could make it
very hard for you to walk and use your knee.
- Unhealthy skin around your
knee
- Severe mental dysfunction
- Poor blood flow in the leg from
peripheral vascular disease. This
could keep the incision from healing.
- A terminal disease, such as
cancer, that has spread
Risks
Risks for any surgery
are:
The risks of this surgery
are:
Before the Procedure
Always tell your doctor or nurse
what drugs you are taking, even drugs, supplements, or herbs you
bought without a prescription
During the 2 weeks before your
surgery:
- Prepare your home.
- Two weeks before surgery you may
be asked to stop taking drugs that make it harder for your blood to
clot. These include aspirin, ibuprofen (Advil, Motrin), naproxen
(Naprosyn, Aleve), and other drugs.
- Ask your doctor which drugs you
should still take on the day of your surgery.
- If you have diabetes, heart
disease, or other medical conditions, your surgeon will ask you to
see your doctor who treats you for these conditions.
- Tell your doctor if you have
been drinking a lot of alcohol, more than 1 or 2 drinks a
day.
- If you smoke, you need to stop.
Ask your doctor or nurse for help. Smoking will slow down wound and
bone healing. Your recovery overall may not be as good if you keep
smoking.
- Always let your doctor know
about any cold, flu, fever, herpes breakout, or other illness you
may have before your surgery.
- You may want to visit a physical
therapist to learn some exercises to do before surgery and to
practice using crutches or a walker.
On the day of your
surgery:
- You will usually be asked not to
drink or eat anything for 6 to 12 hours before the
procedure.
- Take your drugs your doctor told
you to take with a small sip of water.
- Your doctor or nurse will tell
you when to arrive at the hospital.
After the Procedure
You will stay in the hospital for
3 to 5 days, But full recovery will take from 2 to 3 months to a
year.
After surgery:
- You will have a large dressing
(bandage) over your knee. A small drainage tube will be placed
during surgery to help drain fluids that build up in your knee
joint after surgery. It will be removed when you no longer need
it.
- You will have an IV (a catheter,
or tube, that is inserted into a vein, usually in your
arm).
- You may have a Foley catheter inserted into your bladder to
drain urine. Usually it is removed 2 or 3 days after
surgery.
- You will wear special
compression stockings on your legs. These stockings improve blood
flow and reduce your risk of getting blood clots.
- Most people will also receive
blood-thinning medicine to reduce the risk of blood clots
more.
- You may be taught how to use a
device called a spirometer and do
deep breathing and coughing exercises. Doing these exercises will
help prevent pneumonia.
- Your doctor will prescribe pain
medicines to control your pain. Your doctor may also prescribe
antibiotics to prevent infection.
You will be encouraged to start
moving and walking as soon as the first day after
surgery.
- You will be helped out of bed to
a chair on the first day after surgery. When you are in bed, bend
and straighten your ankles often to prevent blood
clots.
- You will be encouraged to do as
much you can for yourself as possible by the second day. This
includes going to the bathroom or taking walks in the hallways,
always with someone helping you.
- Some surgeons recommend using a
continuous passive motion machine (CPM) while you are in bed. The
CPM bends your knee for you. Over time, the rate and amount of
bending will increase. If you are using one, always keep your leg
in the CPM when you are in bed. It will help speed your recovery
and reduce pain, bleeding, and risk of infection.
Some people need a short stay in
a rehabilitation center after they leave the hospital and before
they go home. At a rehab center, you will learn how to safely do
your daily activities on your own.
Outlook (Prognosis)
The results of a total knee
replacement are often excellent. The operation relieves pain for
most people, and most people do not need help walking after they
fully recover. Most artificial knee joints last 10 to 15 years.
Some last as long as 20 years before they loosen and need to be
replaced again.
References
Crockarell JR, Guyton JL.
Arthroplasty of the knee. In: Canale ST, Beatty JH, eds.
Campbell's Operative Orthopaedics. 11th ed.
Philadelphia, Pa: Mosby Elsevier; 2007:chap 6.
Jones CA, Beaupre LA, Johnston
DW, Suarez-Almazor ME. Total joint arthroplasties: current concepts
of patient outcomes after surgery. Rheum Dis Clin North
Am. 2007; 33(1): 71-86.
Review Date: 2/9/2009
Reviewed By: C. Benjamin Ma, MD, Assistant Professor, Chief, Sports
Medicine and Shoulder Service, UCSF Dept of Orthopaedic Surgery.
Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M.,
Inc.
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