Deformation of metal-backed acetabular components and the impact of liner thickness in a cadaveric model.
Summary of "Deformation of metal-backed acetabular components and the impact of liner thickness in a cadaveric model."
Shell deformation of resurfacing and all-metal modular cups following press-fit implantation has been reported, but not for conventional metal-backed cups with polyethylene liners. The deformation of acetabular components with historical and thin polyethylene inserts after press-fit insertion was evaluated using a cadaveric model. All shells and liners deformed upon implantation. Following joint loading, shell pinch decreased from 0.32 to 0.22 mm (p = 0.019) and from 0.29 to 0.13 mm (p = 0.003) for the thin and thick liner groups, respectively. Liner pinch also decreased from 0.17 to 0.04 mm (p = 0.031) and from 0.06 to 0 mm (p = 0.103) for the thin and thick liner groups, respectively. There were no significant differences between the thin and thick liners. Liner deformation was influenced by the initial shell deformation and donor bone quality. Shell and liner pinch decreased following joint loading, suggesting a settling in effect.
Department of Orthopaedic Surgery, Providence Hospital, Southfield, MI, USA.
This article was published in the following journal.
Name: International orthopaedics
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/20625898
- DOI: http://dx.doi.org/10.1007/s00264-010-1077-6
Medical and Biotech [MESH] Definitions
Nuchal Translucency Measurement
A prenatal ultrasonic measurement of the thickness or translucent area below the SKIN in the back of the fetal NECK, or nape of the neck, during the first 11-14 weeks of gestation (PREGNANCY TRIMESTER, FIRST). Abnormal thickness or nuchal translucent measurements resulting from fluid collection, is associated with increased risks of CHROMOSOME ABNORMALITIES. (Nicolaides et al., 1992)
Neutral or negatively charged ligands bonded to metal cations or neutral atoms. The number of ligand atoms to which the metal center is directly bonded is the metal cation's coordination number, and this number is always greater than the regular valence or oxidation number of the metal. A coordination complex can be negative, neutral, or positively charged.
The measurement of subcutaneous fat located directly beneath the skin by grasping a fold of skin and subcutaneous fat between the thumb and forefinger and pulling it away from the underlying muscle tissue. The thickness of the double layer of skin and subcutaneous tissue is then read with a caliper. The five most frequently measured sites are the upper arm, below the scapula, above the hip bone, the abdomen, and the thigh. Its application is the determination of relative fatness, of changes in physical conditioning programs, and of the percentage of body fat in desirable body weight. (From McArdle, et al., Exercise Physiology, 2d ed, p496-8)
Proteases which use a metal, normally ZINC, in the catalytic mechanism. This group of enzymes is inactivated by metal CHELATORS.
The technique of washing tissue specimens with a concentrated solution of a heavy metal salt and letting it dry. The specimen will be covered with a very thin layer of the metal salt, being excluded in areas where an adsorbed macromolecule is present. The macromolecules allow electrons from the beam of an electron microscope to pass much more readily than the heavy metal; thus, a reversed or negative image of the molecule is created.
BACKGROUND: First-generation modular titanium fiber-metal-coated acetabular components had high rates of wear, pelvic osteolysis, and liner dissociation. Second-generation components were designed to...
BACKGROUND: The low wear rates of crosslinked polyethylenes provide the potential to use larger diameters to resist dislocation. However, this requires the use of thinner liners in the acetabular comp...
We identified 128 revision total hip arthroplasties from 1993 to 2005 involving a well-fixed Harris-Galante Porous (HGP)-I or HGP-II acetabular component with minimum 2-year post-revision follow-up. T...
BACKGROUND: Ceramic liner fracture is a concern in THA. However, it is unclear what factors influence the risk of facture. To study these factors under controlled conditions, we...
BACKGROUND: Press-fit acetabular components are susceptible to deformation in an underreamed socket, with excessive deformation of metal-on-metal (MOM) components potentially leading to increased tors...
The primary objective of this investigation is to evaluate the clinical and radiographic outcomes of the ASR™-XL Acetabular Cup System compared to the Pinnacle™ Acetabular Cup with a 2...
The primary objective of this investigation was to evaluate & compare the performance of the P.F.C. Sigma Knee Cruciate-retaining all-polyethylene and metal-backed tibia components using R...
The purpose of this study is to monitor the performance and compare the metal ion release of two bearing combinations, ceramic-on-metal and metal-on-metal in the treatment of patients with...
The investigators want to examine if specific acetabular liner designs can be a contributing factor to audible squeaking associated with CoC bearings. The aim of the present study is to co...
Myocardial deformation imaging allows analysis of myocardial viability in ischemic left ventricular dysfunction. This study will evaluate the predictive value of myocardial deformation ima...