Dual Mobility Hip: New Option in Hip Replacement Doubly Advantageous
Studies Show Newer Implant Offers Lower Risk of Dislocation, Better Range of Motion
(New York, N.Y. April 15, 2015.) Fifty-five year old Allan DeCastro says he “hobbled around” and had serious pain in his hip for five years before making an appointment with Dr. Geoffrey Westrich, an orthopedic surgeon at Hospital for Special Surgery (HSS) in Manhattan. Mr. DeCastro opted for a total hip replacement to alleviate his pain and return to activities he had given up.
Mr. DeCastro, who owns a roofing company, says he’s ecstatic he had the surgery. “It’s an amazing procedure. I’m back to climbing ladders and going up on rooftops,” he said. Feeling better than ever, he has started working out and goes bike riding with his wife.
The New Jersey resident has excellent range of motion and is hoping the implant lasts a long time. And there’s a good chance it will, thanks to a relatively new type of prosthesis he received called a “dual mobility” hip replacement.
“Hip simulator studies have shown that there is reduced wear with this type of implant, which means it should last longer,” said Dr. Westrich, research director, Adult Reconstruction and Joint Replacement at Hospital for Special Surgery.
Reduced wear isn’t the only advantage to the dual mobility hip, according to Dr. Westrich, who has studied the implant and published reports in the American Journal of Orthopedics, the Journal of Arthroplasty, and Hip International.
More than 330,000 total hip replacements are performed in the United States each year. Overall, it is a highly successful procedure. But, as with all surgeries, there is a risk for complications after the procedure.
“With the traditional implant we have had to worry about dislocation, instability, impingement and long-term wear on the plastic part of the prosthesis,” Dr. Westrich said. “The new technology has essentially eliminated most of these issues, including dislocation, the most common complication following hip replacement,” he says.
Although the concept of dual mobility was originally developed in France in the 1970s, the technology is relatively new in the United States. “Dual mobility” refers to the bearing surface of the implant—where the joint surfaces come together to support one’s body weight.
A hip replacement implant is a ball-in-socket mechanism, designed to simulate a human hip joint. Typical components include a stem that inserts into the femur (thigh bone), a ball that replaces the head of the thigh bone, and a shell that lines the hip socket.
Dual-mobility hip components provide an additional bearing surface. “A large polyethylene plastic head fits inside a polished metal hip socket component, and an additional smaller metal or ceramic head is snap-fit within the polyethylene head,” Dr. Westrich explains. “Dual mobility means that there are two areas of motion and therefore less wear. The design virtually eliminates the threat of dislocation as well.”
He adds that patients are greatly relieved when they learn that the risk of dislocation with these newer dual mobility hip replacements is much lower than one percent.
“With improved stability, reduced risk of dislocation and better range of motion, dual mobility implants may ultimately become the prosthesis of choice for younger, more active patients,” Dr. Westrich said. “However, longer term follow-up and additional studies are needed to fully evaluate the current design.”