BACKGROUND: Although hip replacements have been performed for decades, the newest generation of joint replacements involves small bones in the elbow and wrist. Conditions that often lead to a need for replacement are severe fractures and osteoarthritis.

Osteoarthritis is a condition that slowly destroys the cartilage covering the ends of bones. This causes bare bones to rub against each other, such as in the wrist and elbow, resulting in pain, stiffness and weakness.

The condition can develop from normal wear and tear or traumatic injury.

The American Academy of Orthopedic Surgeons (AAOS) says 70 million people in the United States, or one in three, suffer from arthritis.

REPLACING THE WRIST: If arthritis of the wrist becomes so severe that a person cannot conduct their daily activities, a joint replacement may be advised.

The joint of the wrist is formed where the radius and ulna meet the first row of carpals in the hand. Although wrist implants come in many different designs, most have two components: one for each side of the joint.

One component fits into the radius of the forearm while the other fits into a carpal bone in the hand. A spacer fits into the two portions of the implant, enabling a rocking motion. It also allows natural movement of the wrist.

REPLACING THE ELBOW:> The AAOS says osteoarthritis of the elbow is rare since the joint can tolerate large forces without becoming unstable. When the condition does occur, it's usually caused by previous fractures or dislocations.

A common elbow fracture occurs on the radial head, or the portion of the radius near the elbow. These injuries occur in 20 percent of all acute elbow injuries and 10 percent of all elbow dislocations.

A fracture like this increases a patient's chance of developing osteoarthritis down the road.

If arthritis eventually causes the joint surface of the elbow to wear away completely, replacement is often the only measure that can bring pain relief. With an experienced surgeon, results for elbow replacement are typically as favorable as those for hip and knee replacement.

A NEW GENERATION OF IMPLANTS: In a Mayo Clinic study from earlier this year, William Cooney III, M.D., wrote that replacement of the radial head is recommended when the bone is fractured beyond reconstruction.

He recommends it over removing the broken area, since that eventually causes instability of the forearm, even though he concedes that new radial head replacements are short on clinical results.

Joining that group of new replacements are custom-fit radial head and wrist implants designed by William Seitz, M.D., an orthopaedic surgeon at the Cleveland Clinic Lerner College of Medicine in Cleveland, Ohio. His implants are available in a wide variety of standard sizes, but if those sizes don't fit a patient's wrist or elbow, the company will manufacture a custom implant for that patient and send it back within five days.

"The anatomy in that area is very restrictive, and to try to make one-size-fits-everybody doesn't really work," Dr. Seitz said.

A surgeon working on a patient who needs a custom implant would send their X-rays. They are then magnified and used to "fit" the implant, which is made of stainless steel, to that person's anatomy.

The real benefit of Dr. Seitz's implants is the cost. Traditional implants cost between $4,000 and $5,000, Dr. Seitz said, but his cost about half as much.

FOR MORE INFORMATION, PLEASE CONTACT:
Cleveland Clinic Orthopaedic & Rheumatology Institute
(216) 839-3700
http://my.clevelandclinic.org/ortho/default.aspx