If the triple pelvic osteotomy sounds like a back flip by a trapeze artist, it does have similarities. The procedure, designed for the 20-to-40-year-old patient with a severely degenerated and misshapen hip, called developmental hip dysplasia, is complex and risky. Indeed, only a handful of orthopedic surgeons around the world attempt it. "You’re operating fairly deep in the body around structures like the femoral artery and the sciatic nerve that can be injured with drastic results," says orthopedic surgeon Marc Hungerford. "Most surgeons don’t feel comfortable with this procedure." 
| Using anatomical models and computer illustrations, orthopedic surgeon Marc Hungerford explains how he performs his complex procedure for young patients with hip dysplasia. |
But Hungerford, who learned the procedure in Dortmund, Germany, prefers it to the traditional treatment, total hip replacement, in almost all of his dysplasia patients. A new artificial hip relieves the pain caused by friction in an abnormal hip, he says, but it may cause infections, fall out of place or wear out over time, requiring a second operation. "For younger, more active patients, wearing out and dislocation are even more likely," says Hungerford, noting that the average age for hip replacement in the United States is 65. With the triple pelvic osteotomy, natural bone is realigned and restored, reducing the risk of displacement, infection, and wear and tear. But pulling the procedure off is no easy trick. Hungerford first makes three small incisions over the buttock, hip and pubic areas, then cuts the pelvis in each place to free the hip socket, or acetabulum, from the pelvis. Using X-ray guidance, he rotates and repositions the socket fragment, fixing it with screws and wires. Correct rotation of the acetabulum is critical, as the newly positioned socket has to be able to hold the ball-like head of the thigh bone. "You can rotate both laterally and forward to get the bone to cover the top of the ball part of the socket joint," Hungerford explains. "The cartilage has to be in a weight-bearing position and not off to the side." Dysplasia patients’ sockets don’t adequately cover the ball of the femur, which results in the early degeneration. All this must be done while deftly feeling for hidden underlying arteries and nerves. "You have to be careful to cut the bone and not anything else," stresses Hungerford. Cut the femoral artery and you could permanently weaken quadriceps muscles in the leg or, worse, trigger uncontrolled bleeding. Just nick the sciatic nerve and the patient may experience lifelong weakness in the lower legs. Damage the pudendal nerve and numbness in the groin could result. Once the hip fragment is rotated into place, it will heal—and eventually function—naturally. "It’s a durable, natural hip that has a normal distribution of forces across the joint," Hungerford says. After the surgery, patients participate in sports and walk as far as they’d like to. And unlike some hip replacement patients, they don’t worry about dislocation. "It may be the only hip procedure they’ll ever need," the surgeon says. — Gary Logan
Hopkins Medical News, Fall 2001 |
