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Depuy Knee Joint Replacement Failure - Hip Implant Defects
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Alexander Hawes, LLP: DEPUY KNEE AND HIP PROSTHESES FAILURE?
Lawsuits
have been filed against Johnson & Johnson and Depuy
arising out of the alleged failure of the Defendants’ allegedly
defective Ultra High Molecular Weight polyethylene knee joint and hip
replacement prostheses. According to the allegations in the complaints,
the prostheses at issue have been sterilized with gamma radiation, resulting
in premature failure of the product.
If you or a member of your family has a Johnson & Johnson/Depuy Knee Prosthesis made of Ultra High Molecular Weight Polyethylene, you may have a claim.
Contact Alexander Hawes, LLP, immediately to protect your rights.
Click here to have your case evaluated at no charge to you.
Technical
Information
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Technical Information: [^]
In an article posted at http://www.cen.uiuc.edu/~kgordon/assign4.html, it is noted that:
"Ultra-high molecular weight polyethylene is a polymer. The word polymer comes from the Greek word polumeres, which means having many parts. Thus, a polymer is simply many units of atoms that are bonded together to form a long chain. In the case of Ultra-high molecular weight polyethylene (UHMWPE), many polyethylene chains that are extremely long are bound together to form one UHMWPE chain. UHMWPE has a greater toughness and wear resistance than regular polyethylene, but it can wear down in a process that is known as oxidation. During oxidation, oxygen reacts with chain ends of the polyethylene that do not have enough electrons. When the oxygen bonds to the free ends of the polyethylene chains, other molecules that would normally bond to the polyethylene chain cannnot bond to it, and thus the material is degraded or weakened. When a stress is applied to the oxidized UHMWPE, it will wear at a rate that is faster than normal.
"When UHMWPE particles are produced from the articulating motion of implant, the particles are foreign to the body, and as a result the body reacts to them in an unusual way. When the body normally reacts with a foreign material that is in the body during acute inflammation, which is short-term inflammation, phagocytosis occurs. During phagocytosis, a macrophage travels to the foreign body via the white blood cells and attempts to "eat", or dispose of the foreign material.
"When phagocytosis is not successful, and the macrophages cannot dispose of the foreign matter in the body, acute inflammation progresses to chronic, or long term inflammation. Sometimes during chronic inflammation, the white blood cells induce self-injury to the body. This is known as an autoimmune reaction."
[Emphasis added.]
Unfortunately, as stated above, the method used to sterilize these prostheses is well noted for causing oxidation. An article posted at http://www.medical-devices.gov.uk/ notes that:
"The degradative effect of irradiation on polyethylene and other polymers has been known for many years. Chapiro, in his text in 1962, described the mechanisms behind the oxidative degradation of polymers. He noted that ionising radiation interacted with long chain polymers, forming free radicals. In an example, polyethylene was shown to degrade to form a hydrogen radical and a polyethylene radical. The chain scission which was caused in this reaction led to two possible outcomes. Either cross-linking could occur between the polymeric radicals, or, in the presence of oxygen, oxidation of the polymeric chains could occur. In the former case, polymeric chains effectively became longer, and a network structure was formed. In the latter oxidation situation, the polymeric radical could be terminated through the addition of, for example, one of the hydrogen radicals or an oxidation free radical. This termination would lead to lowering of the molecular weight."
Links: [^]
Recalls
Polyethylene Information
- Orthopedics Today: Polyethylene Glossary - (free registration required).
- Orthopedics Today: Guide to Polyethylene in Joint Implants - (free registration required).
- Orthopedics: The Influence of Sterilization Method on Wear Performance of the Low Contact Stress Total Knee System - (free registration required).
Sterilization Information
- Orthopedics Today: Manufacturers work to improve polyethylene for hip prostheses - (free registration required).
- Consequences of Ultra-High Molecular Weight Polyethylene Wear on Total Joint Replacements
- Polyethylene and Polyethylene Wear
Misc.
Notice: [^]
Persons seeking to preserve any potential legal claims for allegedly defective medical products should contact an attorney promptly, since all states have mandatory time periods in which lawsuits must be filed with the courts; otherwise, they may be forever barred. For persons with DePuy implants, they should immediately contact an attorney to discuss their rights.
About Us: [^]
Alexander Hawes, LLP, an AV-rated trial firm, has concentrated its practice on the prosecution of complex Personal Injury and Class Action cases. The Firm represents individuals, governmental entities, businesses and institutional shareholders in auto accident cases, insurance claims, motorcycle injury accidents, and truck (and SUV) accidents. In addition, our law firm represents consumers in defective product, product liability, tort, negligence, mass tort, consumer, construction defect, investment fraud, price fixing and employment cases. The Firm is currently involved in complex cases pending in federal and state courts throughout the Unites States. The Firm is dedicated to quality representation of its clients and prides itself on aggressive advocacy of its clients' claims.
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