The Stryker ABG II Modular-Neck Hip Stems were designed to provide patients with an improved fit when receiving hip replacement surgeries. These hip replacement systems included eight left and eight right stems as well as ten modular style necks that were designed to accommodate individual fitting needs. The system was designed to minimize stress on the surrounding bone and increase stability. The ABG II was made with stems of iron, titanium, zirconium and molybdenum, which made up Stryker’s proprietary titanium alloy. This particular combination of metals was used due to the company’s claims that the blend resisted corrosion and flaking off of the metals into the body. Stryker further argued that the combination was stronger than other available titanium alloys and was a closer match to the bone as well. The stems were used along with cobalt and chromium necks.
Problems with Metal Components
Soon after the ABG II began to be widely used, it was discovered that fretting, which is the flaking off of small pieces of metal was indeed a problem with these systems. The release of these metals resulted in a variety of health issues, including:
- Metal ions entering the tissues surrounding the implant, resulting in metallosis, pain, and bone and tissue death
- Severe allergic reactions due to metal sensitivity, requiring surgery
- Bone loss resulting from metal debris collecting in the joint space around the hip
- The implant loosening after insertion
Each of these conditions required revision surgery to correct the problem. Additionally, there are some studies that indicate that the increased metal ions in the body could lead to additional health problems, including:
- Heart problems
- Neurological problems
- Damage to the spleen, liver, kidneys and lymph nodes
In light of these serious complications and the high number of revision surgeries needed for these implants, Stryker issued a recall on the ABG II in 2012.
FDA 510(k) Approval
The sheer number of issues related to these Stryker implants has led many to wonder how they received FDA approval. The ABG II system was granted approval under the FDA’s Premarket Notification Process (510k). This program allows for the release of a medical drug or device without undergoing clinical trials, providing the product in question is substantially similar to another product that has already been FDA approved. Based on this program, the ABG II, which was similar to other types of hip replacement systems, was granted the approval with the stipulation that Stryker conduct post-market surveillance on patients who received the implants.
The problem with this method of approval for these systems is that the only way to determine any potential problems is after they have been inserted in patients. Additionally, the systems to which these implants were compared were already suspected of potentially having design flaws that led to bone and tissue damage.
The difference between these hip replacements and the ones to which they were compared were due to the other systems using a metal ball and socket. The Stryker model did not use that system, but the same compounds were used in the neck stems, producing the same metal on metal issues related to the previous devices.
Since the voluntary recall, Stryker has been subject to some lawsuits and has agreed to settle some these cases via a single settlement agreement. However, this deal does come with numerous requirements and stipulations.
If you or someone you love has been affected by a Stryker ABG II hip replacement, you are urged to contact an attorney to ensure you receive appropriate compensation for your pain and suffering while dealing with the problems and revisions associated with these hip replacements.