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What
is a Total Hip Replacement?
A hip joint consists of two bones - the
femoral head (the ball) and the acetabulum (the socket). Usually
the joint is well lubricated and the one bone can slide against
the other bone with minimal friction. However, with diseased hips,
the cartilage covering the surface of the bone is worn away and
we now have a situation in which the bones are rubbing against
each other, causing pain and limiting movement. Joints can be
destroyed for a variety of reasons, but arthritis is the most
common. Total Hip Replacement is a surgical procedure which
involves the removal of the diseased bone and the reconstruction
of the anatomy with an artificial joint called a total hip prosthesis.
The components of the prosthesis are designed to act like the
normal joint. There is a femoral stem - a metal component that
is placed into the thigh bone, and an acetabular cup- a plastic
and metal component that is placed where the socket was. There
are two goals with Total Hip Replacement:
- Reduce
or eliminate pain.
- To
restore function by improving the movement of the joint.
What
should you expect?
Blood
Transfusion.
If you are donating blood for your surgery, you will be asked
to donate at least 2 or 3 units of your own blood within 35 days
prior to your surgery date. This will involve scheduling an appointment
with the blood bank of the hospital, or if necessary, a blood
donation facility recommended by your insurance carrier or one
closer to where you live (out-of -state patients). Only one unit
of blood can be donated at a time, so you will need to come in
for at least two visits. The blood is then stored until your operation.
If
you are unable to donate blood, for whatever reason, donor blood
will be used in your case, if necessary. People have expressed
some concern about blood transfusion because of the risk of transmitting
diseases. Donor blood is carefully screened for communicable diseases.
With the new technology, the risk of hepatitis and HIV infection
is extremely low. To our knowledge, disease transmission through
use of donated blood has never occurred in any of our patients.
However, there is no question that your own blood is the safest.
Therefore, if you are able, we recommend that you donate blood
for your surgery. If you're coming a long way, arrangements can
be made to have you give blood locally and have it transported
here for your surgery. Please be assured that blood that you give
will be given back to you, if needed.
Pre-admission
Testing.
Within two weeks prior to your surgery,
you will be asked to undergo several laboratory tests and possibly
an electrocardiogram and chest x-ray. This is called pre-admission
testing. This will help us to tell whether there are any conditions
which might increase the risk of surgery. A physical examination,
performed by your own medical doctor or hospital staff here, is
also a part of pre-admission testing.
Just
Before Surgery.
You will not be allowed to drink or eat
anything after midnight and on the morning of the surgery. In
some cases, you may be allowed to take a medication you normally
take in the morning with a minimal amount of water. If
instructed to do so, you will need to let the admitting nurse
know that you have done this.
When
you come into the hospital on the day of surgery, you may have
some additional x-rays that might not have been taken previously
and have a physical examination by your surgeon or resident. If
you have not already done so, you will be asked to sign an operative
consent form to state that you understand what is being proposed
and that you are in agreement that we may proceed with the operation.
Just prior to surgery, an intravenous line will be started and
you will be taken into the operating suite.
Anesthesia.
You will be seen by an anesthesiologist
on the morning of surgery. Most of our surgeries are performed
under spinal anesthesia. This is a very safe form of anesthesia.
It is safer than general anesthesia, which is one of the reasons
why we recommend it. Spinal anesthesia disturbs the major body
functions a lot less than general anesthesia. Unless there are
some specific reasons why a spinal anesthetic should not be used
in your case, this is our preferred method of anesthesia.
The
anesthesiologist will give you some medication to make you sleepy
so that you're not really aware of what's going on in the operating
room. You will not be totally asleep either. However, the area
that will be operated on will be totally numb throughout the operation
and for several hours after the surgery.
Surgery.
As stated before, the surgery involves the
removal of all of the damaged bone and cartilage. This is done
with saws and drills much like a carpenter uses. The next step
is to prepare the bone for the prosthesis. This involves using
specialized tools to make precise cuts and to shape the bone so
that the prosthesis will fit properly. The artificial joint is
then placed into the bone with or without bone cement. The surgery
itself takes between two to three hours, depending on the complexity
of your case.
Total
hip prostheses can be attached to the bone using a material called
methylmethacrylate or, more simply, bone cement. With proper technique,
this gives an immediate fixation of the prosthesis to the bone.
Another method is called biologic fixation. This method requires
that the surface of the prosthesis next to the bone is porous.
With time, bone grows into the pores and the prosthesis becomes
an integrated part of the joint. There are advantages and disadvantages
to each type of fixation. Furthermore, the type of fixation recommended
to you will depend on your age, weight, and activity level.
Recovery
Room. When
your surgery is completed you will go to the recovery room where
you will be closely monitored until the effects of the anesthesia
and intra-operative medicines are decreased and you are relatively
awake and comfortable.
Orthopaedic
Unit. When
you have completed your stay in the recovery room, you will be
transferred to your hospital room in the orthopaedic nursing unit.
You will be lying on your back in a comfortable position with
a pillow between your legs. The pillow between your legs is designed
so that you will not run the risk of dislocating the hip replacement
in the initial postoperative period. If you have surgery early
in the morning, you may sit up on the edge of the bed that evening.
In general, all patients are out of bed within twenty-four hours
and attending physical and occupational therapy. The therapists
will instruct you in learning how to use crutches or a walker
and being taught some of the precautions that are necessary in
the immediate post-operative period. The physical therapist will
answer any of your questions and will go over all of the details.
Risks.
It is important that you understand that there are risks associated
with any major surgical procedure and total hip replacement is
no exception. These risks include the risk of death. That's true
of any major surgical procedure requiring anesthesia and blood
transfusion. The risk of death in our hospital for total hip replacement
is in the order of 1 per 750 or 1,000 cases so that you can see
that the risk is very small, but it's not 0. The specific risk
for you will depend upon your general medical condition, your
age, and the difficulty of the surgical procedure, but the risk
of death itself is really very small.
There
are, however, some other risks which are a little bit larger.
For example, there is about a 1% risk that your hip will dislocate
in the immediate post-operative period. This may come from an
inadvertent false movement in which the socket of the hip prosthesis
becomes disengaged from the ball (femoral head). In the vast majority
of these cases, this can be treated by manipulation and would
not require another surgical procedure. It might require some
relaxation, it might even require a short anesthetic. But again,
this risk is relatively small, being about 1% of all the cases
that are operated on.
A
major potential risk is the risk of infection. Again, in this
hospital, the risk of infection is in the order of 1 per 200 cases
and we do many things to keep this risk very low. You will be
receiving an antibiotic on the morning of surgery and this will
be continued for 24-36 hours after surgery. There are other preventive
measures that will also be undertaken to reduce the possibility
of infection. Inspite of the measures, a very small percentage
of patients will develop an infection and that generally can be
treated by antibiotics and cured. But occasionally, rarely, it
might result in the hip prosthesis having to be removed. There
is also some risk of an infection elsewhere in your body after
the surgery settling in the hip and therefore we strongly recommend
that patients who have total joint replacement take antibiotics
whenever they have infections in another area. Antibiotics should
also be taken prior to procedures such as sigmoidoscopy, cystoscopy
and routine dental work for the first two years after surgery.
For more information regarding infections and total joints click
here.
There
are a host of other possible complications. If you review series
of several thousand you will see literally dozens of possible
complications that could take place. However, these complications
take place with exceeding rarity. Things
such as muscle ruptures, pulling off of the tendon, injuries to
nerves and blood vessels, superficial infection and opening of
the wound, and other things of this nature may occur. They don't
occur very often, but they can occur.
One
of the things that could occur is the loosening of the prosthesis.
This loosening would not happen suddenly, but it would be a gradual
process and it would be characterized by discomfort. In most instances,
if a prosthesis becomes loose, it can be corrected but that usually
means further surgery. Now what is the nature of this risk? That
depends on several circumstances. We think in general, it's probably
a cumulative risk of about 1% per year, so that if you have your
prosthesis for 20 years, the possibility of loosening over that
20 years could be as high as 1 in 5. If you have your prosthesis
for 10 years, it could be 10%.
Activity.
To a certain extent, what the patient needs
to realize is that an artificial hip can never be as good as a
normal hip. There is always the potential that it may get infected
at some date in the future. It will not tolerate the same kinds
of physical stresses that the normal hip will tolerate. We strongly
recommend against physical activity such as tennis, running, contact
sports, things that can contribute to loosening of the hip through
a physical process and the physical force applied to the hip that
results in motion between the prosthesis and the bone and loosening
and pain. But this is the reason that one has to be cautious about
actually performing a total hip replacement and why it should
only be applied tothose
patients who have severe symptoms.
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