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Overview
The hip is a ball and socket joint. The ball portion of the joint is called
the femoral head, and is part of the upper leg bone (femur). The socket
portion is called the acetabulum, and is part of the pelvic bone. The
femoral head (ball) fits into the acetabulum (socket) and moves within
its natural fluid, called synovial fluid, which helps to lubricate the
joint during motion.


In a
healthy hip joint, the surfaces of these bones where the ball and socket
rub together are very smooth and covered with a tough protective tissue
called cartilage. Arthritis causes damage to the bone surfaces and cartilage.
These damaged surfaces eventually become painful as they wear.
There are many ways to treat the pain caused by arthritis. One way is
total hip replacement surgery. The decision to have total hip replacement
surgery should be made very carefully after consulting your doctor and
learning as much as you can about the hip joint, arthritis, and the surgery.
In total
hip replacement surgery, the ball and socket that have been damaged by
arthritis are removed and replaced with artificial parts made of metal
and a durable plastic material. We call these artificial parts "implants,"
or "prostheses."
Two Types of Hip Fixation
There are two main types of fixation philosophies-cemented and porous.
Both can be effective in the replacement of hip joints. The physician
(and the patient) will choose the best solution that is specific to the
patient's needs. (back
to top)
Cemented Hip Implants
The cemented hip implant is designed to be implanted using bone cement
(a grout that helps position the implant within the bone). Bone cement
is injected into the prepared femoral canal. The surgeon then positions
the implant within the canal and the grout helps to hold it in the desired
position. (back
to top)
Porous Hip Implants
The porous hip implant is designed to be inserted into he prepared femoral
canal without the use of bone cement. Initially, the femoral canal is
prepared so that the implant fits tightly within it. The porous surfaces
on the hip implant are designed to engage the bone within the canal and
permit bone to grow into the porous surface. Eventually, this bone ingrowth
can provide additional fixation to hold the implant in the desired position.

(back
to top)
What
to Bring to the Hospital
Below is a list of things you may want to bring with you to the hospital
in preparation for your surgery. Talk with your physician, as he/she may
have additional information about preparing for your hospital stay.
· Your personal belongings should be left in the car until after
surgery. Tell your family that your room will be assigned when you are
in surgery or in recovery, at which point they can bring your personal
items to your room.
· Personal grooming items that you may want to pack include a toothbrush,
toothpaste, hairbrush, eyeglasses/contacts, comb, deodorant, shaving cream/electric
razor, shampoo, lotion, undergarments, and a robe.
· Bring slippers or flat rubber-soled shoes for walking in the
hallways.
· Bring loose-fitting clothing for your trip home.
· Bring any medications you are currently taking. You should also
write down your medication information to be given to the hospital staff.
Be sure to include the name, strength, and how often you take the medications.
Please communicate any allergies you might have to your doctors and the
nursing staff.
· If you use a breathing exerciser (IBE), be sure to bring it with
you from home, as you will probably need this right after surgery.
· Leave jewelry, credit cards, car and house keys, checkbooks,
and items of personal value at home. Bring only enough pocket money for
items such as newspapers, magazines, etc. (back
to top)
During
Surgery
The patient is first taken into the operating room and given anesthesia.
After the anesthesia has taken effect, the skin around the upper thigh
is thoroughly scrubbed with an antiseptic liquid. An incision of appropriate
size is then made over the hip joint.

(back
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Replacing
the Socket Portion of the Joint
One type of implant that replaces the socket consists of a metal shell
that is lined with a strong plastic liner.

(back
to top)
Removing
the Surface of the Socket
The leg is maneuvered until the femoral head is dislocated from the socket.
A special reamer is then used to remove the damaged cartilage and bone
surface from the acetabulum, and to shape the socket so it will match
the shape of the implant that will be inserted.

(back
to top)
Inserting
the Implant
The shell portion of the socket implant may be attached either by using
a special kind of epoxy cement for bones, or by pressing the implant into
the socket so that it fits very tightly and is held in place by friction.
Some implants may have special surfaces with pores that allow bone to
grow into them to help hold the implant in place. Depending on the condition
of the patient's bone, the surgeon may also decide to use screws to help
hold the implant in place. When the shell portion of the socket implant
is in place, the plastic liner is locked into place inside the shell.
(back to top)
Replacing
the Ball Portion of the Joint
The implant that replaces the ball consists of a long metal stem that
fits down into the femur. The metal ball is mounted on top of this stem.

(back
to top)
Removing
the Ball
A special power saw is used to remove the damaged femoral head.

(back
to top)
Clearing
and Shaping the Canal
The upper leg bone has relatively soft, porous bone tissue around the
center. This part of the bone is called cancellous bone. It surrounds
the canal, which mainly contains blood vessels and fatty tissue.
Special instruments are used to clear some of the cancellous bone from
the canal, and then to mold the inside walls of the canal to fit the shape
of the implant stem.

(back
to top)
Inserting
the Implant
The stem implant may be held in place by either using the special cement
for bones, or by making it fit very tightly in the canal. If cement is
used, it is injected into the canal first, and then the implant is inserted
into the canal. If cement is not used, the implant is simply inserted
into the canal. Like the socket implant, the stem implant may have a special
surface with pores that allow bone to grow into them.
On some implants, the stem and ball are one piece. On others, they may
be two separate pieces. If the ball is a separate piece, it is usually
secured to the top of the stem after the stem has been inserted.

(back
to top)
Closing
the Wound
When all the implants are in place, the surgeon places the new ball that
is now part of the upper leg bone into the new socket that is secure within
the pelvic bone. If necessary, the surgeon may adjust the ligaments that
surround the hip to achieve the best possible hip function.
When
the ligaments are properly adjusted, the surgeon sews the layers of tissue
back into their proper position. A plastic tube may be inserted into the
wound to allow liquids to drain from the site during the first few hours
after surgery. After the tube is inserted, the edges of the skin are sewn
together, and a sterile bandage is applied to the hip. Finally, the patient
is taken to the recovery room. (back to
top)
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