New hip replacement surgery helping keep some active

More than three-quarters of a million people will have a hip replaced this year. But some may be a little gun shy after a large FDA recall of metal-on-metal devices.

They caused inflammation, tissue death, heart and nervous system problems. Now, a new implant is replacing the metal with something safer.

Doctor Steven Harwin has been helping people for 30 years. He has replaced 15 hips a week.

Gilbert Ramirez talked to us a few minutes before he was going to meet up with Doctor Harwin in the OR. As a New York City Tour Guide, he rides all day long.

"You figure there are 20 stops, you're constantly going up and down the stairs,” says Gilbert Rameriz who had a hip replacement. “That's when I noticed my hip started to give me a lot of pressure."

His right hip was wearing bone on bone.

"It stops you dead in your tracks," says Rameriz.

Gilbert is getting a new type of hip replacement called modular dual mobility hip or MDM.

"This is what a contemporary hip replacement looks like," says Dr. Steven Harwin, MD, Chief of Adult Reconstructive Surgery at Beth Israel Medical Center.

A metal shell, a plastic insert and the implant attaches it to the thigh bone.

"The plastic can wear out," describes Dr. Harwin.

The new MDM replacement uses a porus titanium socket that allows bone to grow into it.

"The range of motion is quite large, and the bearings move in conjunction with each other," explains Dr. Harwin.

Tony Renteria had the MDM replacement a month ago. Getting around on foot in the city was a must.

"I could not walk at all," Tony Renteria says about himself before he had a hip replacement.

Now, 30 days after surgery, he's walking without a cane.

"From the next day, I felt absolutely fine,” explains Renteria. “It was like I had no pain whatsoever."

Tony's path to recovery continues. And he's practically pain free, each step of the way.

While it's relatively new in the U.S., the MDM has been used in Europe for decades. Doctor Harwin is one of 30 surgeons worldwide who helped improve the design and update it with more modern, longer lasting materials.

He says about 90 percent of traditional hip replacements last 15 years or longer. He hopes the MDM will give patients even better outcomes by helping reduce dislocation of the implant.


REPORT: MB # 3491

BACKGROUND: The hip is one of the body's largest joints. It is a ball-and-socket joint. The socket is formed by the acetabulum, which is part of the large pelvis bone. The ball is the femoral head, which is the upper end of the femur (thighbone). The bone surfaces of the ball and socket are covered with articular cartilage, a smooth tissue that cushions the ends of the bones and enables them to move easily. A thin tissue called synovial membrane surrounds the hip joint. In a healthy hip, this membrane makes a small amount of fluid that lubricates the cartilage and eliminates almost all friction during hip movement. Bands of tissue called ligaments (the hip capsule) connect the ball to the socket and provide stability to the joint.
COMMON CAUSES: The five most common causes for hip pain are:
• Osteoarthritis. This is an age-related "wear and tear" type of arthritis. It usually occurs in people 50 years of age and older and often in individuals with a family history of arthritis. The cartilage cushioning the bones of the hip wears away. The bones then rub against each other, causing hip pain and stiffness. Osteoarthritis may also be caused or accelerated by subtle irregularities in how the hip developed in childhood.
• Rheumatoid arthritis. This is an autoimmune disease in which the synovial membrane becomes inflamed and thickened. This chronic inflammation can damage the cartilage, leading to pain and stiffness. Rheumatoid arthritis is the most common type of a group of disorders termed "inflammatory arthritis."
• Post-traumatic arthritis. This can follow a serious hip injury or fracture. The cartilage may become damaged and lead to hip pain and stiffness over time.
• Avascular necrosis. An injury to the hip, such as a dislocation or fracture, may limit the blood supply to the femoral head. This is called avascular necrosis. The lack of blood may cause the surface of the bone to collapse, and arthritis will result. Some diseases can also cause avascular necrosis.
• Childhood hip disease. Some infants and children have hip problems. Even though the problems are successfully treated during childhood, they may still cause arthritis later on in life. This happens because the hip may not grow normally, and the joint surfaces are affected.

WIPING OUT PAIN: The Modular Dual Mobility (MDM) hip replacement uses a small metal or ceramic head that fits into a larger high- tech plastic head. The large plastic head then fits inside a smooth metal cup. Because of the large plastic head, the MDM renders the joint extremely stable so that active patients can engage in recreational and sports activities. The large head also allows a greater, more normal range of motion than standard implants. The small head moves within the plastic large head, and it in turn moves in the socket. This design is called a "dual mobility" cup.
• Materials: Using a combination of high-tech, new-generation plastics, ultra- smooth metals, ceramics and porous metals, the wear rate has been reduced over 97% and a long-lasting natural adherence to the bone occurs
• Surgical Technique: Minimally invasive surgical techniques use smaller incisions, cause less muscle damage and allow patients to recover faster.
• Recovery: After less-invasive MDM hip replacement, patients recover faster with no precautions after surgery. Patients can sit, stand, walk and move their hip without fear of it coming out of place. Most patients are recovered in three to four weeks and can drive, travel and return to normal activities. Patients have an excellent chance that their replaced hip will provide them a high quality of life for decades to come. (Source:


Vera Ricciardi, Practice Administrator
Denise M. Mazza, Office Manager
(212) (861) 9800

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