Track topics on Twitter Track topics that are important to you
Vitamin E incorporated highly cross linked polyethylene (E-XLPE) was developed to increase oxidative resistance of highly cross-linked polyethylene (XLPE) without affecting mechanical properties. The investigators evaluated this type of polyethylene in a randomized clinical study, using Radiostereometric Analysis (RSA). The objective of this study was to compare the early-term wear of E-XLPE to a compression annealed polyethylene liner (C-XLPE, ArComXL®). The clinical outcome at two years was not expected to be affected by the choice of polyethylene.
First generation of modern highly cross-linked polyethylene (XLPE) was clinically introduced in 1998 and has in most countries become standard as bearing surface in total hip arthroplasty. Studies of these materials have shown significantly reduced femoral head penetration when compared to gamma sterilized conventional polyethylene.
Thermaly treating (melting or annealing) is often a part of the manufacturing process of highly cross-linked polyethylenes. The polyethylene is exposed to irradiation to achieve cross-linking and improve wear resistance. Cross-linking by irradiation increases the amount of free radicals in the material.These radicals must be eliminated or stabilized to avoid oxidative degradation over time.Thermal treatment improves oxidation resistance but potentially changes the mechanical properties of the polyethylene.
By annealing i.e. heat treatment under the melt temperature the material maintains better mechanical properties, but elimination of free radicals is suboptimal, which can lead to oxidation in vivo.Heat treatment of the polyethylene above the melt temperature will more effectively reduce or eliminate the amount of residual free radicals. This will increase oxidation resistance, but will negatively influence the mechanical properties of the material.
Due to these limitations new generations of cross-linked polyethylene materials have been developed. Introducing Vitamin E (α-tocopherol), a natural antioxidant into the material prevents oxidative degradation and stabilizes the free radicals found in irradiated polyethylene plastic. In laboratory tests, polyethylene liners with incorporated vitamin-E have demonstrated similar wear, greater strength and better resistance to oxidation compared with the first generation cross-linked polyethylene. Currently, there are only laboratory studies on vitamin E diffused polyethylene available.
The hypothesis in this study is that the early-term E-XLPE wear is low and comparable to a heat-treated XLPE. The investigators also hypothesize that implant fixation and clinical outcome at two years will be unaffected by the choice of polyethylene.
The investigators therefore evaluated the early bedding in and wear in an uncemented arthroplasty supplied with liners made of vitamin E diffusion doped XLPE (E1®, Biomet, Warsaw, IN, USA). In the control group the investigators used the same uncemented hip prosthesis with polyethylene liners manufactured to achieve high levels of crosslinking without sacrificing the mechanical strength and extinguish residual free radicals (ArComXL® , Biomet, Warzaw, IN, USA).
Allocation: Randomized, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Investigator), Primary Purpose: Supportive Care
Sahlgrenska University Hospital, Sweden
Published on BioPortfolio: 2016-06-15T17:53:22-0400
The purpose of this data collection is to determine long term survival rate of ArComXL® highly cross-linked polyethylene
The purpose of this study is to evaluate FluMist with and without Ampligen in healthy volunteers.
The purpose of this study is to determine what side effects CP 870,893 may cause when given with an immune stimulant called Oncovir poly IC:LC along with a melanoma vaccine. The CP 870,893...
The purpose of this study is to test an approach of stimulating the body's immune system to attack prostate cancer. This study will test injection of a substance polylysine and carboxymeth...
RATIONALE: Biological therapies such as poly-ICLC use different ways to stimulate the immune system and stop tumor cells from growing. PURPOSE: This phase II trial is studying how poly-IC...
Hyperuricemia is a common condition, and in a subset of patients leads to gout, the most common inflammatory arthritis. Osteoarthritis is the most common form of arthritis overall, and gout and osteoa...
To examine the effect of the circadian gene Clock on posttranscriptional function and pro-inflammatory mechanisms in osteoarthritis.
Introduction: Medico-social significance of osteoarthritis is due to a number of factors, one of which is associated with the need for long-term anti-inflammatory therapy, which is associated with und...
The aim of this narrative review is to summarize important findings from biochemical marker studies relevant to osteoarthritis (OA) in the context of new discoveries and clinical and scientific need.
To estimate cause-specific mortality in osteoarthritis patients compared to the general population.
A poly(A) binding protein that is involved in promoting the extension of the poly A tails of MRNA. The protein requires a minimum of ten ADENOSINE nucleotides in order for binding to mRNA. Once bound it works in conjunction with CLEAVAGE AND POLYADENYLATION SPECIFICITY FACTOR to stimulate the rate of poly A synthesis by POLY A POLYMERASE. Once poly-A tails reach around 250 nucleotides in length poly(A) binding protein II no longer stimulates POLYADENYLATION. Mutations within a GCG repeat region in the gene for poly(A) binding protein II have been shown to cause the disease MUSCULAR DYSTROPHY, OCULOPHARYNGEAL.
A poly(ADP-ribose) polymerase that contains two ZINC FINGERS in its N-terminal DNA-binding region. It modifies NUCLEAR PROTEINS involved in chromatin architecture and BASE EXCISION REPAIR with POLY ADENOSINE DIPHOSPHATE RIBOSE.
A poly(A) binding protein that has a variety of functions such as mRNA stabilization and protection of RNA from nuclease activity. Although poly(A) binding protein I is considered a major cytoplasmic RNA-binding protein it is also found in the CELL NUCLEUS and may be involved in transport of mRNP particles.
Post-translational modification of proteins with POLY ADENOSINE DIPHOSPHATE RIBOSE.
The addition of a tail of polyadenylic acid (POLY A) to the 3' end of mRNA (RNA, MESSENGER). Polyadenylation involves recognizing the processing site signal, (AAUAAA), and cleaving of the mRNA to create a 3' OH terminal end to which poly A polymerase (POLYNUCLEOTIDE ADENYLYLTRANSFERASE) adds 60-200 adenylate residues. The 3' end processing of some messenger RNAs, such as histone mRNA, is carried out by a different process that does not include the addition of poly A as described here.
Within medicine, nutrition (the study of food and the effect of its components on the body) has many different roles. Appropriate nutrition can help prevent certain diseases, or treat others. In critically ill patients, artificial feeding by tubes need t...
A joint is where two or more bones come together, like the knee, hip, elbow, or shoulder. Joints can be damaged by many types of injuries or diseases, including Arthritis - inflammation of a joint causes pain, stiffness, and swelling with ...
Arthroplasty is a surgical procedure to restore the integrity and function of a joint. A joint can be restored by resurfacing the bones. An artificial joint (called a prosthesis) may also be used. Various types of arthritis may affect the joints. Osteo...