Stryker Hip Replacements
The Stryker Orthopaedics manufactures medical devices for joint and bone replacement procedures as well as other products for the surgical profession. They hold over 5,300 patents for products ranging from hip replacement and bone prosthetic devices to blood clot removal devices and data analytic programs. Stryker operates in over 100 countries around the globe and has yearly sales of over $9 billion.
Some of Stryker’s best-selling products have included their hip replacement devices used for total or partial hip replacement surgeries. Several of these devices have come under fire and required recalls to mitigate a risk for early failure, serious injury and requirement for revision surgery.
Stryker hip replacement devices which have been particularly problematic include:
- Stryker Rejuvenate modular-neck stem
- Stryker ABG-II modular-neck stem
- Stryker LFIT V40 (metal) Femoral head
Stryker Rejuvenate and ABG-II Modular Neck Stem Devices
The Stryker Rejuvenate modular-neck stem for use in hip replacement surgery was approved by the U.S. Food and Drug Administration (FDA) in June of 2008 and the Stryker ABG-II modular-neck stem device was approved in November of 2009. Both products were marketed for “younger” patients and advertised as “high performance” devices which were intended to be more durable and longer-lasting. The Rejuvenate system included 6 stems and 16 necks, while the ABG-II system had 8 right stems, 8 left stems and 10 necks for a variety of configurations.
The devices were designed to more closely model the biomechanics and anatomy of the human hip and to provide enhanced stability. The were both also engineered as a modular unit to make implantation easier for the physician who could choose components to best fit a particular patient. The Rejuvenate and ABG-II systems were not designed as strictly metal-on-metal implants which had already been shown to be problematic but were supposed to resist metal fatigue and corrosion. Unfortunately, patients were still exposed to significant risks caused by the devices and their construction of titanium, zirconium, molybdenum and iron.
Both the Rejuvenate and ABG-II hip replacement devices were recalled in 2012 and discontinued within three years of introduction due to an abnormally high number of cases of metallosis and other side effects were shown to be caused by corrosion and fritting of the modular-neck stems.
Stryker LFIT V40 Femoral Head
The Stryker LFIT V40 Femoral Head is a part of Stryker’s modular system which is used in replacement surgery to replace the top portion of the large leg bone, or femur. It was approved in 2001 and was designed to be used as a component with other Stryker components. The LFIT V40 device is constructed of the metals cobalt and chromium which were believed to be exceedingly durable and quite safe. The design was intended to match patient anatomy and mimic natural biomechanics to provide increased range of motion and reduce dislocation events.
Unfortunately, in 2016, Stryker was forced to recall multiple model numbers of the LFIT V40 (CoCr) Femoral Head devices due to a high risk of taper lock failure. Failure of the femoral head could lead to hip dislocation, unseating of the head from the leg bone, fracture of the hip and/or leg, increased metallic debris and other complications. In 2017, the LFIT recall was expanded to include additional devices from the same line.
Stryker Hip Replacement Side Effects
Stryker hip replacement devices can cause serious adverse events and severe side effects. Many of these side effects are a result of metal fragments and ions which are shed from the implant into surrounding tissue.
Severe side effects include:
- Metallosis – poisoning of the surrounding tissue by metal fragments which have been released through grating of the implant surfaces on one another
- Necrosis – tissue death in surrounding areas, likely due to metallosis toxicity
- Osteolysis – dissolution of bone tissue from contact with metal fragments and toxicity
- Pseudotumors – formation of “false” tumors which are large collections of solid or semi-solid mass around the implant.
Revision surgery is usually required to replace a failed implant. Many patients who require revision surgery also require one or more reconstructive surgeries.
The FDA 510(k) approval process
Normally, the Food and Drug Administration requires that new medical devices undergo the Premarket Approval (PMA) process. Similar to new drug approvals, the PMA requires that a new medical device undergoes clinical testing in human patients according to stringent guidelines and that sufficient valid scientific evidence is presented that provides reasonable assurance that the device is safe and effective for its intended use.
The Stryker hip replacement products which have caused a greater-than-expected number of serious injuries were approved under the FDA 510(k) process. This is a “fast-track” process which allows manufactures to skip clinical testing by claiming that a device is similar to other products which are already on the market.
Because the Stryker products were approved under the 510(k) and not the PMA, Stryker hip replacement devices were never tested in humans. The failure to conduct suitable clinical testing may have been responsible for many of the injuries which could have been prevented if problems had been identified.
Stryker Hip Replacement Lawsuits
Many patients who have been injured by a Stryker hip replacement device have filed lawsuits against the company. Some lawsuits have already been settled but thousands more remain in federal, state and local courts and more may be expected.