Prothèse totale de hanche

thumb|Une prothèse de hanche en titane, un couple de glissement constitué d'une tête fémorale en céramique et d'un cotyle en polyéthylène. Une prothèse totale de hanche (PTH) est un dispositif articulaire interne qui vise à remplacer l'articulation de la hanche et lui permettre un fonctionnement quasi normal, en tout cas permettant la marche.

Une PTH dite de « première intention » est une prothèse posée sur une hanche en principe « vierge », par opposition à ** la « reprise de PTH » ou même ** la « PTH de reprise » d'une hanche déjà opérée, voire déjà infectée.

Histoire des prothèses 1920-1980 Prothèses de hanches 1920-1980 Du fond de la mythologie, la première endoprothèse était née. Au début du , les chirurgiens orthopédistes sont confrontés à deux types d’atteinte de la hanche: l’arthrose et la fracture du col du fémur. Les conséquences de l’arthrose sont connues. Avec l’usure, du cartilage disparaît, ce précieux revêtement qui permet le glissement h

Micromotion measurement around femoral stem for the long-term success of total hip arthroplasty

The primary stability of cementless femoral components is crucial for the long-term success of total hip arthroplasty. The mechanisms which influence this stability are not yet well understood. However, mechanical environment in peri-implant tissue is known to be a key parameter in this context. Particularly, implant loading induces local micromotions at the bone-implant interface and affects the stability of the implant. In this project we are interested to characterize these micromotions and to interpret them into clinical solutions. In the first part of the project, we propose to design a loading device which allows to apply loads on bones in-vitro and to generate these micromotions. In the second part, student will use the microCT scan system to take images of bone under different loads and finally a home-made algorithm should be developed for micromotion measurement and statistical analyses. The work uses both biomechanics and image processing principles.

2012

New/Surface-Modified Biocompatible Polymer for ICD Lead Insulation

Rubin Berek Pisarek

The average lifetime of an implanted pacemaker or defibrillator cable (lead) is approximately 10 years. One of the main lead failure mechanisms is deterioration of the insulation, which can be caused by chemical, biological, and mechanical processes. Each time lead failure occurs, an operation for its prompt replacement is required, in order to guarantee the patients' well-being. Since lead failure poses a health risk for the patients, and replacement operations are costly, this study aims at the improvement of one of the materials which is used by the cardiac pacing industry. Silicone polymers are commonly used for pacemaker and defibrillator lead insulation. Previous studies showed that some modified polyurethane polymers exhibit very different as well as favorable mechanical surface properties, as compared to their unmodified counterparts. This was due to the fact that polymeric blocs within the network can migrate to the materials' surface, and thereby act as surface-modifying end-groups (SMEs). In this study, a commercially available silicone system was modified by introducing two different SMEs and using two different approaches. In one approach the SMEs were covalently bonded to the silicone backbone, and in the second approach carrier molecules with the SMEs attached to them were admixed to the silicone. The carriers themselves had a siloxane backbone. The tensile properties, tear strength, and hardness were measured in order to describe the material as compared to commercially available mixtures, and to improve the mixing ratio of the components. Protein adhesion, water uptake, and surface wettability were evaluated to investigate the effect of the SMEs on the surface properties of the novel silicone formulations. While the mechanical properties of the silicone mixtures are comparable to but not competitive with the commercially available materials, contact angle measurement showed a significant reduction of the surface hydrophobicity: The initial contact angle of ∼114° could be reduced to ∼55°. It was concluded that the two novel SMEs can be used in order to make initially hydrophobic silicone hydrophilic.

EPFL2011

New/Surface-Modified Biocompatible Polymer for ICD Lead Insulation

Rubin Berek Pisarek

EPFL2011

Bone strain around the hip implant

Micromotion measurement around femoral stem for the long-term success of total hip arthroplasty

New/Surface-Modified Biocompatible Polymer for ICD Lead Insulation

Bone strain around the hip implant

Micromotion measurement around femoral stem for the long-term success of total hip arthroplasty

New/Surface-Modified Biocompatible Polymer for ICD Lead Insulation