Orthopedics

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.

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.

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."

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.

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.

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.

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.