Issues Surrounding the Design Failure of the Stryker Rejuvenate and ABGII
Patients who were implanted with a Stryker Rejuvenate or Stryker ABGII hip implant are likely wondering just what went wrong after a recall was issued for the two devices in July, 2012. Problems with metal hip implants have been in the news often in the past few years, particularly the DePuy ASR and the Stryker Rejuvenate and ABGII. Because the Stryker recalled models are not considered “true” metal-on-metal hip implants, they were not expected to cause the fretting, corrosion and shedding of metal ion debris that other all-metal hip implants have experienced. Stryker used a ceramic ball rather than a metal ball, thus reducing the risk of friction between the ball and the neck piece. In fact, the designs of the Stryker ABGII and Rejuvenate were considered particularly innovative, in that they offered a dual modularity design which implemented a femoral head/neck Morse taper junction and a femoral neck/stem Morse taper junction.
The Stryker Rejuvenate design failure is a bit different from that of the Stryker ABGII design failure, although the design of the two recalled devices have much in common. Both the ABGII and the Rejuvenate offer surgeons a wide range of components in different lengths and angles which allows for a more custom fit. The Rejuvenate implements a longer stem which is placed more deeply into the femur during surgery—and can be more difficult to remove in the event a revision surgery becomes necessary. The ABGII stem is shorter, thus easier to remove. In both models the metal neck piece can rub against the metal stem, thus the array of hip implant components offered by Stryker—although offering greater range of motion—also resulted in serious medical problems among implant recipients.
Problems with the Coating on the Stryker Rejuvenate and ABGII
Stryker Rejuvenate coating problems came to light after the recall was issued; Stryker ABGII coating problems and Stryker Rejuvenate coating problems actually began as selling points for the Stryker design. Stryker sprayed their hip implant components with a proprietary blend of titanium, molybdenum, zirconium and iron (TMZF) as a means of dealing with mismatched components. When mixing the titanium stem with a cobalt and chromium neck, there is a greater tendency for cobalt and chromium ions to shear away from the implant device. Some believe it is due to the fact that both cobalt and chromium are harder metals than titanium, but whatever the reason, Stryker felt that coating the components with this blend would decrease the amount of friction between mismatched components. Studies have shown that the Stryker ABGII and Rejuvenate actually release greater amounts of cobalt than chromium. Whether the release of excess cobalt ions relates to the TMZF coating and is a contributor to the fretting and corrosion experienced by patients is undetermined.
Problems with Fretting and Corrosion on the Stryker Rejuvenate and ABGII
The neck junction of the ABGII and Rejuvenate is more prone to fretting and corrosion than other metal hip implants leading to the shedding of excess metal ion debris. At the time Stryker recalled the two hip implants Stryker Rejuvenate fretting and Stryker ABGII fretting were primary concerns. Once fretting and corrosion occurs in the implant it is only a matter of time before cobalt and chromium ions begin to build up in the tissues and bloodstream. These metal ions can lead to metallosis as well as toxic buildup of cobalt and chromium in the bloodstream. Inflammation, chronic pain, destruction and death of tissue and bone and hip failure can result from Stryker Rejuvenate Corrosion and Stryker ABGII Corrosion. Those who have experienced serious medical issues after being implanted with a Stryker ABGII or Rejuvenate should visit with their physician as well as a knowledgeable Stryker hip recall attorney.