“Hip” Definitions:A Discussion of Medical Terms Every DePuy Hip Implant Recipient Should Know
February 18, 2012
July of 2003 saw the worldwide introduction of the metal-on-metal hip replacement by DePuy, although these devices were not used for hip replacement surgeries in the United States until 2005. Johnson & Johnson, the parent company of DePuy, pushed the approval of the hip implant device through the FDA under an expedited process known as the 510(k). This process allows many medical devices to skip rigorous clinical trials when the manufacturer can show the device is substantially equivalent to another device which has already received approval. At the time of the 510(k) approval, DePuy claimed the ASR hip replacement device raised no new issues of safety or effectiveness.
Complaints Regarding the DePuy Implant
Over the next few years, the FDA began receiving a flood of complaints regarding these devices, and many of the DePuy metal-on-metal hip implants had to be removed for the health of the recipient. Although a traditional metal-on-metal hip implant device can reasonably be expected to last at least fifteen years, the DePuy devices were failing at a much higher—and earlier—rate. Even though DePuy was notified of the health issues surrounding the implant as early as 2007, they continued to market the hip implants until August 26, 2010, when DePuy and Johnson & Johnson finally issued a voluntary Depuy hip extensive recall of the implant system. Those who have undergone the hip implant surgery with a DePuy implant may be confused regarding the potential health risks and uncertain of how to proceed and should be aware that a DePuy hip replacement lawsuit is an option.
Incidence of Revision Surgery Following a DePuy Hip Implant
While not all recipients of the DePuy hip implant will require replacement surgery, it is estimated that at least 13% of the hip implantations will require revision surgery within five years of the initial implantation, and that a possible 49% of the hip implants are susceptible to failure within six years. At a medical conference in Ireland in early 2011, it was stated that as many as 1700 out of 3500 Irish hip implant recipients required revision surgery—a number substantially higher than DePuy’s own 13% estimate. As you can see, there is no definitive answer as to whether or not you will require a revision surgery following your DePuy hip implant failure, and whether that device will cause you subsequent medical issues whether minor or severe.
Why Hip Implant Replacement Surgery May Be Necessary
Some of the problems noted by physicians who have replaced the defective DePuy hip implants are loosening of the cups, dislocation, lack of bone growth into the cups and inflammation or other issues related to the metal shavings which are released into the body. Some patients experience metallosis which indicates the presence of tiny metal particles which have accumulated in the fluid surrounding the tissues of the area and are tinged with a gray color. If the fluid surrounding the tissues is yellow-tinged this is known as “serous” and means the tissues are relatively normal, with only small amounts of the metal particles present.
Should the fluid be tinged with blood, it is called “sero-sanguinous” and this typically indicates a loose component in the implant which has caused trauma and bleeding to the bone. A thick, milky or cloudy fluid may first indicate infection, and can be tied to adverse reactions to the metal-on-metal bearing surfaces. In many cases, the fluids from a failed DePuy hip replacement appear to be toxic to human tissue cells, leading to damage or an unusual appearance.
When the Tissues inside the Joint are Damaged
In certain cases, the tissue within the joint capsule can break down following the original hip replacement surgery, meaning it will not be repairable because the soft-tissue hip envelope is gone. This can be quite serious for the person who needs a replacement surgery after the removal of the DePuy implant. This breakdown of tissue can also lead to a much higher dislocation rate should revision surgery be attempted. In some cases, there can be a thickening of the synovium, or joint lining, which makes it appear as though there is a tumor or cancer in the joint. This “pseudo-tumor” is actually due to chronic inflammation of the joint as a result of the metal wear particles. These pseudo-tumors can lead to serious pain, inflammation, and popping and catching of the hip joint.
Loss of bone, or osteolysis, is generally related to joint inflammation which invades the bone and breaks it down. The body may not discriminate, eating up both the metal shavings as well as the patient’s bone. If osteolysis is present in tissues surrounding the hip socket, the socket itself may be loosened, rendering revision surgery much more difficult—or impossible—as there is less bone to work with. If osteolysis is present around the femur, it can lead to a fracture at the top of the femur which is a medical issue that can be quite problematic for the surgeon to deal with. There is an osteolysis grading system based on x-rays, however it is not considered especially useful. Your surgeon might use such terms as “radiolucencies in zones 1, 2 or 3 of the acetabulum” which indicates a loss of bone behind the components which make up the hip. In any case, this loss of bone as a result of the metal-on-metal DePuy hip replacement can make revision surgery difficult to impossible.
Deciphering the Pathologist’s Report
If you are attempting to understand the pathology report from your DePuy hip replacement device, the following terms could be helpful. Lymphocytes are white blood cells which are typically involved in a reaction that is similar to an allergy reaction. Lymphocytes can also be the body’s response to chronic inflammation in the body and in both cases is known as lymphocytic infiltration. This type of infiltration is different than a poly-morphonucleocyte inflammatory infection.
When the body responds in a certain way to the metal-on-metal hip implant, this reaction may resemble an allergic reaction when scrutinized under a microscope and is termed ALVAL or aseptic lymphocyte dominated vasculitis associated lesions. The lymphocytes are believed to be a response to the hip replacements metallic degradation and they often congregate around tiny blood vessels although they can be present in tissue as well. While there is no current grading system for the severity of ALVAL, by its presence alone the physician becomes aware of a chronic metal-on-metal problem.
Necrosis may be present in any area surrounding the hip implant where the blood supply is less rich. Any tissues which don’t have a good supply of blood are at risk for poor healing, therefore potentially severe infection. Cells which eat foreign bodies are known as either macrophages or histiocytes, and in those patients who have undergone a hip replacement surgery they can be observed in the area of the hip, attempting to eat the metal debris. Once they consume these metal shavings, however, they may form granulomas which can lead to further complications.
Don’t Sign a Release without Prior Legal Advice
As you can see, there are many potentially serious problems with the DePuy hip implant device; as part of the recall, DePuy is asking hip implant recipients to sign a medical release as well as return the faulty implant once it has been removed from the body. The indication is they will only pay costs they consider to be reasonable and directly related to the removal of the hip implant. Unfortunately, this offer is less than generous, with no compensation offered for the necessity of the replacement hip surgery, the chronic pain or the lost wages the DePuy hip replacement recipient has likely undergone, not to mention the pain and suffering.
It’s important that you not sign anything without first speaking to a knowledgeable hip recall attorney who is skilled in product liability cases and who can more fully determine your legal rights. Should you sign the DePuy release without first obtaining legal counsel, you may unknowingly be giving DePuy the right to obtain your medical records and your future rights to Medicare could be compromised as well. Signing the release generally requires that your hip implant be turned over to DePuy as soon as it is removed, which can significantly limit your future legal options and recovery.