Defects Associated with DePuy ASR XL Acetabular Hip Implant System
In response to numerous complaints and new clinical data on the increased rate of defects associated with DePuy ASR XL Acetabular hip implant systems, DePuy Orthopedics voluntarily recalled all of its ASR XL Acetabular hip replacement devices, as announced by the company in August 2010.
The Depuy ASR XL Acetabular Hip Replacement system became available worldwide in July 2003. This medical device was used as the total hip replacement implant for patients with rheumatoid arthritis or otherwise damaged hip bones. Most of the hip replacement surgeries were successful. However, in 2010, new unpublished data from the National Joint Registry of England and Wales appeared, showing an increased failure rate of DePuy total hip implants. Per the DePuy Surgeon Recall Pack, the five year revision rate for DePuy ASR XL Acetabular System is about 13 percent, which is twice the average industry rate. In other words, approximately 1 of 8 patients with DePuy hip implant will need a revision surgery. The highest risk was indicated among female recipients and those, who received ASR head sizes below 50 mm in diameter.
What is the DePuy ASR XL Acetabular Hip Implant System?
DePuy ASR XL Acetabular hip implant system is a medical device, used for hip replacement surgery. During this procedure damaged socket and ball are removed and an implant is inserted instead of a natural hip joint. A hip implant system consists of two parts – socket, which is attached to the cup-shaped bone of the pelvis, called acetabulum, and metal ball with stem, which is inserted into the femur bone. The ball moves in the socket imitating the natural functioning of the hip joint. Images below illustrate the hip replacement procedure and DePuy ASR XL Acetabular system.
Defects Associated with DePuy ASR XL Acetabular Hip Implant System
According to Dr. Kevin J. Bozic, MD, an orthopedic surgeon at San Francisco Medical Center, in reference to DePuy hip implants recall: “It was a design failure that frankly was not picked up until they were implanted in thousands of patients.” The DePuy ASR Surgeon Recall Pack contains a detailed listing of defects associated with the ASR XL Acetabular hip implants. These defects include component loosing and malalignment, dislocation of the elements, infection, fracture of the bone, metal sensitivity, and pain.
Depuy Implants and Genotoxicity
British Orthopedic Association advised the Medicines and Healthcare products Regulatory Agency (MHRA) of the UK, that over time metal debris may affect the performance of a hip implant and cause painful complications. Furthermore, the same expert group links metal hip implants, such as DePuy AST to genotoxicity. The local exposure to metal debris causes the chromosomes of bone marrow or white blood cells to breakdown. Genotoxic effects may result in cancer or even heritable defects, if reproductive cells are affected. However, “These effects indicate that exposure to a genotoxic agent has occurred but do not necessarily mean that cancer or heritable defects will result.”
The Depuy Hip Defects are Not A Surprise
Finally, orthopedic surgeons around the US noticed defects associated with DePuy ASR XL Acetabular hip implants long before the official products were recalled. According to Dr. Joshua J. Jacobs from the Rush University Medical Center, “Most major medical centers have seen issues with this device. This does not come as a surprise.”