Claude Rieker

Zimmer Biomet

Trunnionosis, defined as wear and corrosion at the head-neck taper connection, is a cause of failure in hip arthroplasty. Trunnionosis is linked to a synergistic combination of factors related to the prosthesis, the patient, and the surgeon. This review presents analytical models that allow for the quantification of the impact of these factors, wit...

We present a model to estimate the osteolysis-free life of total hip arthroplasty, depending on linear wear rate and femoral head size. An estimate of the radiologic osteolysis threshold was calculated, which was based on volumetric wear. The osteolysis-free life of the cup was estimated from the quotient of the osteolysis threshold and volumetric...

Articulating components should minimise the generation of wear particles in order to optimize long-term survival of the prosthesis. A good understanding of tribological properties helps the orthopaedic surgeon to choose the most suitable bearing for each individual patient. Conventional and highly cross-linked polyethylene articulating either with...

Generell müssen Hüftprothesen so gestaltet sein, dass sie sich auf sichere Art implantieren lassen und als lasttragende Bauteile ihre Funktion wahrnehmen können. Dahingehend sind sie auf die jeweilig vorliegende Indikation abgestimmt, in die Operationstechnik eingebunden, planbar und entsprechend instrumentiert. Sie erlauben die gewünschte Rekonstr...

The purpose of this review is to examine alternative bearings used in total hip arthroplasty (THA) and discuss the specific tribologic needs of the "New Orthopaedic Patient". As orthopaedic patients today are younger and more active, there is a clear need for hip joint implants and articulations minimising the amount of wear and guarantying better...

Six metacarpophalangeal prostheses were each wear tested to five million cycles. Each prosthesis consisted of a metacarpal component with an approximately hemispherical shell on a titanium body, articulating against a titanium phalangeal component. Four prostheses had a shell made from ultra-high molecular weight polyethylene (UHMWPE) and two had a...

The transient elastohydrodynamic lubrication (EHL) analysis was performed in this study for a typical metal-on-metal bearing employing a polyethylene backing underneath a metallic cup inlay under dynamic operating conditions of load and speed representative of normal walking. A ball-in-socket configuration was adopted to represent the articulation...

The purpose of this review is to examine alternative bearings used in total hip arthroplasty (THA) and discuss the specific tribologic needs of the “New Orthopaedic Patient”. As orthopaedic patients today are younger and more active, there is a clear need for hip joint implants and articulations minimising the amount of wear and guarantying better...

The effect of geometry change of the bearing surfaces owing to wear on the elastohydrodynamic lubrication (EHL) of metal-on-metal (MOM) hip bearings has been investigated theoretically in the present study. A particular MOM Metasul bearing (Zimmer GmbH) was considered, and was tested in a hip simulator using diluted bovine serum. The geometry of th...

The finite element method was employed in this study to compare the contact mechanics at the bearing surfaces between a metal-on-metal hip resurfacing prosthesis and a total hip replacement with a similar bearing combination. The hip resurfacing prosthesis was implanted and modelled in a full three-dimensional pelvic and femoral bone. A significant...

Large-diameter metal-on-metal articulations may provide an opportunity for wear reduction in total hip implants because earlier studies have shown that the formation of a fluid film that completely separates the bearing surfaces is theoretically possible. In such a lubrication mode and under ideal conditions, there is theoretically no amount of wea...

Wear of total joint replacements is determined gravimetrically in simulator studies. A mix of bovine serum, distilled water, and additives is intended to replicate the lubrication conditions in-vivo. Weight gain due to fluid absorption during testing of UHMWPE components is corrected using a load soak station. In this study six sets of UHMWPE pins...

This paper summarizes hip simulator and retrieval studies that were done to optimize 1 design of a second-generation metal-on-metal hip replacement. It was determined that clearance is the first key parameter controlling wear behaviour. The clearance should be as small as possible while as large as necessary to avoid any equatorial contact leading...

This paper summarizes hip simulator and retrieval studies that were done to optimize 1 design of a second-generation metal-on-metal hip replacement. It was determined that clearance is the first key parameter controlling wear behaviour. The clearance should be as small as possible while as large as necessary to avoid any equatorial contact leading...

The elastohydrodynamic lubrication (EHL) analysis was carried out in this study for a 28 mm diameter metal-on-metal hip prosthesis employing a metallic cup with an ultra-high molecular weight polyethylene (UHMWPE) backing under a simple steady state rotation representing the flexion/extension during walking. Both Reynolds and elasticity equations w...

The OXINIUM technology, developed by Smith & Nephew, is designed to oxidize a wrought 97.5% zirconium – 2.5% niobium alloy by means of thermal diffusion and so create a zirconia surface about 5 μm thick [1], as shown in Figure 1 [1]. Figure 1 The OXINIUM technology.

The purpose of this study was to investigate the influence of a dose of e-beam irradiation on the mechanical and tribological properties of crosslinked UHMWPE. Specimens of UHMWPE were irradiated at different dose levels between 0 and 110 kGy using the WIAM e-beam process. Irradiation was followed by melt annealing and slow cooling. In general, the...

Highly cross-linked ultra high molecular weight polyethylenes (UHMWPEs) were developed to reduce UHMWPE wear in arthroplasty. These UHMWPEs have manifested a significant improvement in the in-vitro adhesive-abrasive wear resistance of total joint prostheses. As such, the ripples with micro-fissures observed on the surface of clinically retrieved co...

Highly cross-linked, ultrahigh-molecular-weight polyethylenes (UHMWPEs) were developed to reduce UHMWPE wear in arthroplasty. These UHMWPEs have manifested an improvement in the wear resistance. Examination of the first retrievals revealed surface features not usually observed on conventional retrievals. A flattening of the machining marks is evide...

It is the goal of this paper to introduce modern tribological investigations into the development of a new finger prosthesis, with the particular aim of optimising the material component.A new, unconstrained metacarpophalangeal prosthesis restoring the anatomy of the joint has been developed in two versions (UHMWPE-metal and PEEK-metal). In order t...

An improvement in tribology of bearing surfaces is an effective means of increasing the longevity of total hip replacement (THR). Currently, 3 approaches are available to achieve this aim: first, use of highly cross-linked UHMWPE; second, aluminum oxide ceramic bearings, and third, metal-on-metal bearings. Cross-linking reduces the wear resistance...

The contact mechanics in metal-on-metal hip implants employing a cobalt chromium acetabular cup with an ultra-high molecular weight polyethylene (UHMWPE) backing were analysed in the present study using the finite element method. A general modelling methodology was developed to examine the effects of the interfacial boundary conditions between the...

Die Arbeit soll aufzeigen, welche modernen Untersuchungsverfahren eingesetzt werden knnen, um die Entwicklung einer neuen Fingerprothese, v. a. hinsichtlich der Materialwahl optimieren zu knnen.In Anlehnung an die ursprngliche Gelenkanatomie wurden 2 Versionen einer neuen, nicht gekoppelten, metakarpophalangealen Prothese entwickelt, die sich ledig...

The wear of ultra high molecular weight polyethylene (UHMWPE) is the major cause of aseptic loosening in total joint prostheses (6).

231 cobalt-chromium metal-on-metal (METASUL design) retrieved articulations (297 retrieved components) were examined for their in vivo wear behaviour. A running-in period of about one year is observed where the in vivo wear rate for the whole articulation is approximately 35 μm/year. After this running-in period, the measured in vivo wear rate of t...

231 cobalt-chromium metal-on-metal (METASUL design) retrieved articulations (297 retrieved components) were examined for their in vivo wear behaviour. A running-in period of about one year is observed where the in vivo wear rate for the whole articulation is approximately 35 μm/year. After this running-in period, the measured in vivo wear rate of t...

The first generation, metal-on-metal articulation from cobalt-chromium-molybdenum alloy produced by Sulzer Ltd. has been in use for 40 years. Former drawbacks concerning geometry, tolerance or metallurgy have been eliminated in the second generation METASUL components used since 1988. These are also free of disadvantages, such as potential fracture...

Polyethylene particle disease is one of the major causes of late aseptic loosening of total hip replacement. Two hard-hard articulations (alumina-on-alumina and metal-on-metal) have been developed in Europe as an alternative to the ultra-high molecular weight polyethylene (UHMWPE) articulations. Even though these hard-hard articulations are on the...

Osteolysis is due to particulate wear debris and is responsible for the long-term failure of total hip replacements. It has stimulated the development of alternative joint surfaces such as metal-on-metal or ceramic-on-ceramic implants. Since 1988 the second-generation metal-on-metal implant Metasul has been used in over 60 000 hips. Analysis of 118...

Osteolysis is due to particulate wear debris and is responsible for the long-term failure of total hip replacements. It has stimulated the development of alternative joint surfaces such as metal-on-metal or ceramic-on-ceramic implants. Since 1988 the second-generation metal-on-metal implant Metasul has been used in over 60 000 hips. Analysis of 118...

Description Although in widespread use in certain centers abroad, alternative bearing surfaces are currently in the developmental or early clinical stage in the United States. There are numerous manufacturing, regulatory, scientific, and clinical issues that need to be carefully examined prior to the widespread introduction of these devices. STP 13...

As wear is inevitable with artificial joint replacement, it has to be minimized to avoid possible aseptic loosening following osteolysis due to particle-initiated foreign body reaction. Co-Cr-Mo-C alloys have a long history with only minimum wear when articulating with themselves. This investigation shows that the choice of the alloy has an effect...

Two stainless steel alloys with molybdenum and boron were rapidly solidified by laser melting or by melt spinning. According to the composition of the steel, two types of microstructure, either a columnar epitaxial structure or an equiaxed microcrystalline structure, were observed. Two conditions have to be fulfilled to ensure the equiaxed microstr...

Crystal nucleation during rapid solidification generally occurs rather slowly except at active heterogeneities or unless very large undercoolings are achieved. Many typical microstructures are then essentially of columnar morphology, for example from the bottom surface of a melt-spun ribbon or from a heterigeneity on the surface of a powder particl...

One possibility for surface treatment using lasers is to cause significant changes in surface composition and microstructure. However, techniques for changing composition remain poorly developed and the mechanisms controlling final microstructure are still not fully understood. A very simple technique for supplying alloying additions has been used...

Laser alloying has been used to create hard surface layers on a ferritic stainless steel. Alloying elements were introduced very simply by painting the steel surface with a suitably charged paint. The materials obtained were examined by electron metallographic techniques and analysed by energy-dispersive spectroscopy and diffraction. Suitable contr...

Elastohydrodynamic lubrication of metal-on-metal (MOM) hip implants was investigated theoretically under transient operating conditions representing a typical in-vitro simulator testing. A standard 28mm diameter Metasul TM MOM bearing (Centerpulse Orthopedics, A Zimmer Company) with a nominal radial clearance of 60µm was considered. The transient v...