Manufactured Parts and Hip Replacements

Total Hip Arthroplasty

Every year approximately 200,000 hip replacement surgeries are performed in the United States and the success rate appears to be about 90 percent. The most common reason for hip replacement is osteoarthritis of the hip joint; however, surgery is not a “quick fix” for every person with chronic hip pain. Surgery, in this instance is used only after medication and other, less-aggressive treatments have failed.
More than 21 million people in the United States have degenerative osteoarthritis, and it is the leading cause of chronic disability. The number of arthritis related hospital admissions doubled between 1993 and 2006.

Most people undergo hip replacement as a result of osteoarthritis of the hip joint. But you might also consider hip replacement if you experience severe pain, loss of motion or deformity of your hip joint. Hip replacement is also used in people with hip injuries, rheumatoid arthritis, impaired nerves, loss of muscle strength surrounding the joint, and other medical conditions, such as a bone tumor or bone loss due to insufficient blood supply (avascular necrosis).

Symptoms that may lead to the decision to undergo hip replacement include severe pain and loss of motion or stiffness in the joint. Pain that keeps you awake at night, little or no relief from pain medications, difficulty walking up or down stairs, trouble standing from a seated position, or having to stop activities because of pain are additional considerations that can lead to interference in everyday living.

Today’s hip prosthetics can be expected to last up to 20 years. Usually hip replacement has been an option for adults older than age 60. Because the newer technology has brought about stronger and longer lasting artificial joints, younger and more active people are choosing this surgery.

Hip replacement may be the only choice after failure of other less invasive therapy fails to relive increasing pain. While hip replacement, or total hip arthroplasty, can relieve pain and improve range of motion, it is not without risk.

The current rate of obesity is of major concern to surgeons who provide this type of orthopedic surgery. Only recently has this data been made available through the Mayo Clinic.

Researchers have found that there is a 50 percent increase in complications when obesity and super obesity is present. In order to be considered a “best candidate” for hip replacement surgery, there must first be significant joint and cartilage damage shown on X-ray, severe and deep pain, no relief from medication for pain and inflammation, and interference in daily activities of living.

Usually if a patient has disabling heart disease, uncontrolled high blood pressure, infection or very poor overall health, this surgery will not be scheduled.
Currently either metal-metal or ceramic-metal hip prostheses are used in replacement surgery.

A third type of prosthetic hip joint was in use from 2003 until 2008. In July 2008, the “Zimmer Durom Acetabular Cup,” a metal-polyethylene prosthetic device, was removed from the market. At that time the manufacturer began a significant effort to provide new training to orthopedic and general surgeons and began to develop new educational support materials.

Considered by surgeons for at least 30 years to be highly durable, the Metal-on-Polyethylene prostheses had been the leading artificial hip component material and had been approved.

The Zimmer Durom hip replacement device is made with a cobalt chrome molybdenum alloy metal ball with a polyethylene liner. Polyethylene is the most understood and had been the most used of all liner materials, which offered surgeons a range of stability options while the operation was underway.

The ability of polyethylene to be adaptively customized during surgery is considered important; however it is the least expensive bearing.

Since all implants, including the Zimmer Durom hip implant device, are subject to wear and tear, they shed debris. After about 10 to 15 years of use the debris shows up with symptoms of inflammation and bone loss. The wear rate of Metal-on-Polyethylene implants, such as the Zimmer Durom hip replacement device, is about 0.1 millimeters a year.

To overcome the issue of “debris” manufacturers chose to treat the polyethylene liners with radiation to create new wear resistant polyethylene. This new substance is called “highly cross linked polyethylene.”

In July 2008, after reviewing data on more than 3,000 cases, Zimmer, the world's largest manufacturer of hip replacement parts, suspended sales of the Zimmer Durom Acetabular Component (Durom Cup).

The Indiana-based manufacturer states that it was unaware of any design or manufacturing defects and a Zimmer Durom hip recall was not issued. Zimmer has plans to place the Durom Cup back on the market on completion of its training and education projects.

Several Zimmer Durom hip implant lawsuits have been filed against Zimmer Holdings Inc., claiming it failed to provide proper warnings, instructions and training to surgeons.

In early 2008, one prominent orthopedic surgeon wrote openly about problems he experienced with Zimmer Durom hip replacements. His data showed that out of 165 implants, 14 were "revised or required revision" within the first two years after surgery. The surgeon added that he believed the Zimmer Durom hip replacement device was defective and there were seating problems with the surface where fixation in the natural joint was to occur.

Zimmer advised that people who have received the Durom Cup to contact their doctor if they experience pain more than three months after surgery.

This article is part of a consumer health education series written by Gayle Eversole, DHom, PhD, MH, NP, ND, of Creating Health Institute, in collaboration with Bernstein Liebhard, LLP.

The views expressed in this article are solely those of the author, Gayle Eversole.

Posted in: avascular necrosis. consumer injury lawyers,hip arthroplasty,hip replacement,natural health news,Zimmer Durom Acetabular Cup