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The elbow is a hinge joint consisting of three
bones. The upper part of the hinge is at the end of the upper arm
bone (humerus), and the lower part of the hinge is at the top of
the two forearm bones (radius and ulna) which are side by side.
When the elbow is bent, the ends of the two forearm bones rub
against the end of the humerus.
Bones of Elbow Joint
In a healthy elbow joint, the surfaces of these
bones are very smooth and covered with a tough protective tissue
called cartilage. Arthritis causes damage to the bone surfaces and
cartilage where the three bones rub together. These damaged
surfaces eventually become painful.
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Arthritic Elbow Joint Surfaces
There are many ways to treat the pain caused by
arthritis. One way is total elbow replacement surgery. The decision
to have total elbow replacement surgery should be made very
carefully after consulting your doctor and learning as much as you
can about the elbow joint, arthritis, and the surgery.
In total elbow replacement surgery, an
artificial hinge made of metal and a very durable plastic material
is inserted into the joint so that the elbow can move without
allowing the two forearm bones to contact the humerus. We call this
artificial hinge an "implant."
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Getting to the Joint
The patient is first taken into the operating
room and given anesthesia. After the anesthesia has taken effect,
the skin around the elbow is thoroughly scrubbed and sterilized
with an antiseptic liquid. A tourniquet is then applied to the
upper portion of the arm to help slow the flow of blood.
An incision about six inches long is then made
over the elbow joint. The incision is gradually made deeper through
muscle and other tissue until the bones of the elbow joint are
exposed.
Preparing the Bones
One of the forearm bones, the ulna, has a
projection at the end, which extends up and behind the end of the
humerus. A special power saw is used to remove part of this
projection.
This allows the two forearm bones to be rotated
out of the way so parts of the humerus can be removed with the saw.
Precision guides are used to help make sure that the cuts are made
so the bones will align properly after the implant is inserted.
The middle portion at the end of the humerus is
removed first.
The arm bones have relatively soft, porous bone
tissue in the center. This part of the bone is called the "canal."
Special instruments are used to clear some of this soft bone from
the canal of the humerus. These instruments also help shape the
canal to fit the shape of the implant.
Then, similar instruments are used to clear
some of the soft bone and shape the canal of the ulna.
Attaching the Implants
The elbow implant consists of two metal stems
that are connected by a metal locking pin. This pin passes through
the ends of both stems, which are lined with a strong plastic
material, serving as a bearing that allows the elbow to bend. The
stems are inserted into each of the two prepared canals. A special
kind of cement for bones is first injected into the canals to help
hold the stems in place.
When the cement is hard, the two implant parts
are brought together and the pin is inserted to connect them.
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Stems Locked Together
to Create
Hinge
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Closing the Wound
If necessary, the surgeon may adjust the
ligaments that surround the elbow to achieve the best possible
elbow function.
When all of the implants are in place and 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. The edges of the skin are
then sewn together, and the elbow is wrapped in a sterile bandage.
Finally, the patient is taken to the recovery room.
