Ankle Replacements –Growing Stepchild of Hips & Knees (Orthopedics This Week)
Although the basic technology for ankle replacements was developed about 30 years ago, widespread acceptance did not take off—as it did for hips and knees—in part because the ankle technology was not yet satisfactory. In the 1970s, “everybody gave up on them,” said James Bodsky, M.D., an orthopedic surgeon in Dallas and a clinical professor of orthopedic surgery at the University of Texas Southwestern Medical School. He is quoted October 17 by Ellyn Couvillion of the Baton Rouge Advocate.
That situation has now changed and Brodsky finds ankle replacement to be “a very exciting area. It does a huge amount of good.” The ankle joint holds different challenges for surgeons than do the hip or knee surgeries, which may account for the longer timeline in the development of successful ankle prostheses and related technology.
“The ankle joint is a very unforgiving joint; there are basically bones on three sides of it,” said Steven Haddad, M.D. a spokesperson for the American Academy of Orthopaedic Surgeons and an orthopedic surgeon in Wilmette, Illinois, who specializes in foot and ankle issues. “The ankle bone is about a quarter the size of the knee. It’s a small interface for the prosthesis to grow into the bone.”
As Couvillion explained, the ankle joint is actually formed by three separate bones: the lower end of the shinbone, the lower end of the smaller leg bone and the top of the foot bone. In an ankle replacement procedure, the surgeon removes the damaged portions of those bones and reshapes them. The parts of the new artificial joint are then attached to the bony surfaces. Recovery typically entails a partial cast or splint following surgery, followed by a hard cast, then a walking cast or boot for several weeks before physical therapy begins.
Since the ankle has the weight of the entire body on it, the forces on the ankle are greater than those on either the hips or the knees. Brodsky notes that, “It requires extensive knowledge about the biomechanics of the foot and ankle. It’s quite complicated. The foot and ankle have to be well-aligned.”
The Food and Drug Administration has approved four ankle prosthetics for use in the U.S., although there are about 50 in use throughout the world. A major benefit of ankle replacement is that the person retains movement in the ankle joint. On the negative side is the fact that the implants are not permanent; they last an average of 10 years. For that reason it is rare for people in their 20s and 30s to have the ankle replacement surgery. A further problem is that some insurance companies, according to doctors, are still calling the surgery experimental.