In August 2010, the DePuy Orthopaedic division of Johnson & Johnson recalled the ASR XL Acetabular and Hip Resurfacing Systems due to a high failure rate compared to traditional hip implants. Patients fitted with the DePuy implants were advised to meet with their orthopedic surgeons to determine if they might require a hip “revision” or the replacement of their hip prosthesis.
The DePuy hip implants were touted by the company as the device that should be used in younger and active patients because the metal-on-metal design would have a longer life and the design would allow the patient to remain active.
Unfortunately, studies have shown that the metal-on-metal design of the hip implant caused cobalt and chromium ions, or metal artifacts, to be released into the patient’s tissue which caused a number of complications.
One complication is that metal released in a patient’s system can cause pseudo-tumors or granulomas. A granulomatous reaction can occur when immune cells called macrophages wall off foreign substances that the body is unable to eliminate. In the case of the metal-on-metal hip implants, the masses can form as an immune reaction to metal debris. These pseudo-tumors can also contain necrosis, or dead cells.
If a pseudo-tumor grows large, it can cause loosening of the hip joint and it can eat away at the bone.
What tests can determine the presence of a pseudo-tumor?
Doctors have several tests which they can use to determine what is causing a patient’s symptoms or to see how the hip implant is doing.
Sonograms is a diagnostic tool that is non-invasive and uses sound waves to generate an image that a medical profession can uses to assess and diagnose. It can be used to look at soft tissue masses and bone surfaces. It is often used as an initial screening tool as it is inexpensive and easy to perform.
Magnetic resonance imaging (MRI)
MRI’s can be costly exams but they are able to provide detailed visualizations of internal structures. They can show reactive masses such as pseudotumors because they can show contrast of the different soft tissues of the body.
A CT scan can also be a useful tool with its 3-D imaging to show pseudo-tumors. However, the MRI provides a greater contrast between the various soft tissue.
DePuy hip implant replacement patients are also advised to have a blood test which can determine whether there is an excess of metal in the bloodstream. Some patients with the DePuy hip implant have been found to have cobalt and chromium levels at more than 100 times a normal level. Metal at high levels is known to be a cancer causing agent.
This information is provided by Washington Injury Attorney blog, a service of The Farber Law Group. We represents patients throughout western Washington and the Pacific Northwest who have had their DePuy artificial hip recalled.
British orthopedics group estimates DePuy ASR hip implant failure may reach 49%
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