Zimmer Hip Replacements

Section Guide

Total hip replacement, called total hip arthroplasty by doctors, is a surgical procedure that relieves pain and restores range of motion in hips that are damaged either by injury or diseases. There are multiple ways this type of damage can occur.

Osteoarthritis, a medical condition in which cartilage that provides a cushion for the hip wears away. When this happens, bones rub against each other, and friction causes pain and stiffness.

Rheumatoid arthritis, a disease in which too much of the lubricating fluid in the hip joint is produced and damages the cushioning cartilage.

Traumatic arthritis, a type of arthritis caused when cushioning cartilage is injured.

Zimmer Holdings, Inc. manufactures a number of hip replacement devices and parts. The variety is intentional, designed to give orthopedic surgeons as many options as possible when choosing the right prosthesis for a patient.

Total Hip Replacement Success

When orthopedic surgeons perform hip replacement surgery, they have to make decisions about the type of prosthesis to use. They must pick the medical device to replace the non-functioning joint. They have a number of choices to make, including:

Whether to perform a standard operation, in which the incision is between five to eight inches in length, or a inimically invasive procedure using an incision that is only four inches long.
What type of prosthesis fabrication to use, such as metal-on-metal, metal-on-ceramic, or ceramic-on-ceramic. That means that the stem that is implanted is typically made of metal, but in some instances it can be ceramic. The replacement for the ball or head of the thigh bone can be either, and the shell that fits over the ball is usually made of metal.
Whether to use prosthesis whose surface is treated with a coating, something to prevent corrosion.
Whether the prosthesis will be cemented in place.

Zimmer Makes Many Hip Replacement Products

Hip replacement devices manufactured by Zimmer include the Zimmer® M/L Taper Hip Prosthesis, and the company believes it uses special technology to make the devices sound and also cutting-edge.

Zimmer M/L Taper Hip Prosthesis

Previous hip replacement devices were limited in size and shape. Surgeons had to make the hip bone fit the implant. Zimmer devices use what the company calls Zimmer Kinectiv Technology, which has four parts instead of three, so the surgeon can choose each component of the replacement prosthesis in a size and shape that best matches the patient’s actual hip.

The Fitmore Hip Stem: The Fitmore Hip Stem is designed to be used in minimally invasive procedures, providing a number of benefits:

Quicker recovery time and less postoperative pain because the surrounding muscles, tendons, and nerves are not as traumatized as in standard hip replacement surgery.
Less scarring because the incision is smaller than with standard hip replacement.
Quicker stabilizing of the implant because muscle function isn’t interrupted during the procedure. Lack of muscle disruption also means less time spent in rehabilitation after surgery.

Continuum Acetabular system: The Trabecular Metal Technology used in this device is a three-dimensional material that is supposed to simulate the body’s spongy bone. It should provide a high level of friction allowing the hip joint to quickly stabilize after being implanted. It should also allow ingrowth into the hip implant.

Metasul Metal-on-Metal articulation: The type of hip joint is forged metal, instead of cast like traditional hip replacements. This is supposed to make it harder and smoother, which should make it more durable.

FDA Asks for More Hip Replacement Studies

In May 2011, the Food and Drug Administration (FDA) sent letters to Zimmer and 19 other manufacturers of hip replacement devices requesting more study of the levels of cobalt and chromium in patients who receive all metal replacements. The FDA asked for information for eight years following the implanting of a device. An FDA’s investigation is focused on all-metal devices with high failure rates that were subject to recalls.

These devices came under more intense scrutiny by regulators because of public concern about their safety. There is not enough clinical evidence to determine the concentration of metal ions that will not cause adverse reactions in patients.

The FDA began investigating metal-on-metal hip replacement devices because of recent studies that found that “a small number of patients in which high levels of metal ions in the bloodstream may have caused other types of symptoms or illnesses elsewhere in the body, including effects on the heart, nervous system, and thyroid gland.”

It is also believed that high blood levels of these metals may also be associated with increased pain, damage to tissue and additional surgeries to repair hip replacement devices that are not working properly.

Problems with Zimmer’s Durom Cup Discovered in 2008

Zimmer Holdings, Inc. manufacturers the Durom Cup, a hip socket constructed from metal. In 2007, Lawrence Dorr, M.D., a nationally recognized orthopedic surgeon and a paid consultant for Zimmer, reported his problems with the Durom Cup. He said that within a few months after implanting the Durom Cup in patients, the device failed and caused a great pain. In some cases, he performed corrective surgery to replace the hip replacement device. Zimmer blamed the problems on Dorr’s technique and not on its Durom Cup.

Dorr in 2008 told colleagues in a professional association about his experiences with the Durom Cup. He then discovered other doctors had similar experiences.

Zimmer Hip Replacement Lawsuits

Many patients who received metal-on-metal hips manufactured by Zimmer have filed lawsuits against the company because they had to have the devices removed after they failed in only a few years. A hip replacement prostheses should last at least 15 years.

In 2008, Zimmer Holdings, Inc. put $47.5 million in reserve to pay claims won by defendants who sued over the failure of the Durom Cup. Zimmer noted that the money was not being reserved for all surgical revisions but only for revisions resulting from procedures that occurred before the company’s voluntary suspension of the product and which were performed within two years of the original surgery.