Memphis (Tenn.) Daily News—April 9, 2009
Every Wednesday “the bad elbow club” meets at Hospital for Special Surgery in New York, joked Timothy Wright, Ph.D.
The comment was a rare moment of levity in a speech this week in Memphis about a very serious subject. Wright, who is also the hospital’s chair of orthopedic biomechanics, spoke at the University of Memphis’ FedEx Institute of Technology about the difficulties with total elbow replacements. The lecture is one of a series sponsored each year by the InMotion Musculoskeletal Institute.
Loss of the use of an elbow can be especially debilitating, he said, and prevent people from doing the most basic daily tasks without help.
The failure rate for total elbow replacements is much higher.
“The elbow, even at five years, a third of them have already failed,” Wright said. “If I take those numbers and I carry them out to 10 years, they get even worse. Only half of them are surviving at 10 years. So think about it. If you are 70, you have only a 50-50 chance that your elbow replacement is going to last until you are 80.”
The elbow is a very complicated hinge joint that allows a wide range of movements. Besides the difficulty of mimicking these functions, designers of replacement joints also have the added challenge of inserting a flange (a type of rod) into the ulna, a small bone in the lower arm that is prone to osteolysis or dissolving.
Wright’s research focuses on friction and wear issues. The wear can cause very small particles to break loose that are about 200 times smaller than a grain of sand, Wright noted in a history he wrote of joint replacement implant materials.
“The body mounts a cellular reaction to try to deal with the wear debris, a reaction that unfortunately often leads to unwanted destruction of bone (called osteolysis) around the implant,” he wrote in the report. “When osteolysis becomes severe, it can cause pain and loosening of the implant and the need for revision surgery to replace the components. One way to relieve the ostelysis problem and thus increase the longevity of joint replacements is to improve the wear resistance of the bearing materials.”
Surgeons have had some better results with custom-made implants, he said, pointing out that one replacement has lasted as long as 24 years.
People who live with rheumatoid arthritis are among those who need total elbow replacements. Wright called for further research into improving medical devices and decreasing complications.
“These are devastating failures,” he said. “Sure if your hip or knee hurts or you lose function in the lower extremity that is devastating, but if your upper extremity still works you can go to the bathroom, you can feed yourself, you can comb your hair, you can get in and out of a car. If you don’t have the function of your elbow, you can’t.”