What Makes the Stryker Rejuvenate one of the Most Dangerous Hip Implants on the Market?

It seems that one hip implant after another is being recalled as more and more potential health risks come to light. The Stryker Rejuvenate was recalled in July, 2012 after it was discovered the neck juncture could corrode, leading to the release of metal ions in the body. Prior to the Rejuvenate recall several of the metal-on-metal hip implants suffered their own issues: recalls, adverse reports and lawsuits. When the Stryker Rejuvenate gained FDA approval in June of 2008, it was hailed as a truly innovative as well as much safer alternative to the metal-on-metal implants which were constructed of a cobalt and chromium head and acetabular cup.

In the all-metal hip implants the ball and cup rubbed against one another during periods of activity, causing tiny metal particles to shear away and imbed in the surrounding tissues or travel to the bloodstream. The Rejuvenate implemented a ceramic ball, leading experts to believe it would be much safer than the all-metal implants. Surgeons initially loved the Rejuvenate because of its modular design; the surgeon was able to choose a stem, neck, ball and cup based on the size of the person as well as their activity level and how they walked. This variety of angles and lengths of the modular implant gave surgeons much more flexibility and theoretically provided the recipient with a better, longer-lasting hip implant.

Although the Rejuvenate did not have the amount of metal surface to rub together as the metal-on-metal implants, there was much more potential for metal shear than originally thought. Not only did the metal neck juncture show signs of corrosion, the metal trundles located on either end of the neck portion were also subject to corrosion as fluids became trapped underneath. While the levels of metal shear in the Rejuvenate would be unlikely to reach the levels from all-metal implants, any amount of cobalt and chromium in the body above the normal levels of 0.5 parts per billion likely mean corrosion has occurred. Once corrosion has taken place, there is the threat of tissue necrosis, bone loss, hip failure and symptoms of metal toxicity.

While the typical toxic metal levels are lower in the Rejuvenate patient than in patients with all-metal implants in their body, the Rejuvenate is much more dangerous simply because of the manner in which it must be removed during revision surgery. When an all-metal implant such as the Pinnacle fails and revision surgery is necessary, the surgeon opens up the hip area and replaces the metal liner with a plastic liner. The surgery takes less than an hour and is considered relatively safe. Should the ABG fail and revision surgery become necessary, the acetabular cup must be removed and replaced. Again, a relatively simple surgical procedure unless the bone has grown into the cup in which case the surgery becomes both more complex as well as more painful.

What is notable about either of these surgeries is that the surgeon will never touch the stem of the implant. During the original hip replacement surgery the stem of the implant is placed deeply into the femur, then after the surgery the femoral bone will grow around the stem. Because of the location of the metal trundles, should revision surgery become necessary for a Rejuvenate recipient, the stem must literally be dug out of the femur. During this procedure, the femur can shatter or fracture, leading to further problems. Even under the best circumstances, the revision surgery for a Rejuvenate can take from four to five hours a lengthy time for a patient to be on the operating table. Excessive blood loss, infection and very long recovery times are all hallmarks of the Rejuvenate revision surgery. Those who have a Rejuvenate hip implant are advised to have regular blood tests to monitor their cobalt and chromium levels as well as other tests recommended by their physician.