Complications of patellofemoral arthroplasty often occur soon after implantation and, as well as other factors, can be due to the design of the implant or its surgical positioning. A number of studies have previously considered the wear of ultra-high-molecular-weight polyethylene patellae following suboptimal implantation; however, studies have primarily been carried out under a limited number ...

A friction energy formalism is considered and adapted to formalize the fretting wear responses of adhesive wear and non-adhesive wear interfaces. It is shown that for non-adhesive wear tribocouples like hard coatings (TiN, TiC, etc.) the wear kinetics can be formalized using the accumulated friction dissipated energy. By contrast, adhesive wear contacts involving aluminium and titanium alloys d...

This paper proposes two new classes of imperfect repair models. The failure process without repair is supposed to be a Non Homogeneous Poisson Process (NHPP). The repair e ect is characterized by the change induced on the failure intensity before and after failure. In the rst class of models, repair e ect is expressed by a reduction of failure intensity. In the second class, repair e ect is exp...

BACKGROUND The number of primary total knee replacement procedures has rapidly increased worldwide because of the high success rates. The incidence of failure of total knee replacements has concurrently increased. Determining the causes of failure is very important for devising treatment and plan for future prevention strategies. MATERIAL AND METHOD A retrospective study was done with patient...

The Articular Surface Replacement (ASR) hip resurfacing arthroplasty has a failure rate of 12.0% at five years, compared with 4.3% for the Birmingham Hip Resurfacing (BHR). We analysed 66 ASR and 64 BHR explanted metal-on-metal hip replacements with the aim of understanding their mechanisms of failure. We measured the linear wear rates of the acetabular and femoral components and analysed the c...

Wear particle-induced biological responses are the major factors resulting in the loosening and then failure of total joint arthroplasties. It is feasible to improve the lubrication and reduce the wear of artificial joint system. Polyetheretherketone (PEEK) is considered as a potential bearing material due to its mechanical characteristics of resistance to fatigue strain. The PEEK wear particle...

background: the interim restorative materials should have certain mechanical properties to withstand in oral cavity. the aim of this study was to evaluate the hardness and wear resistance ofinterim restorative materials. materials and methods: fifteen identical rectangular shape specimens with dimensions of 2 mm × 10 mm × 30 mm were made from 7 interim materials (tempspan, protemp 3 garant, rev...

We sought to establish the incidence of joint failure secondary to adverse reaction to metal debris (ARMD) following metal-on-metal hip resurfacing in a large, three surgeon, multicentre study involving 4226 hips with a follow-up of 10 to 142 months. Three implants were studied: the Articular Surface Replacement; the Birmingham Hip Resurfacing; and the Conserve Plus. Retrieved implants underwen...

The current paper aims to review tooling life span, failure modes and models in cold microforming processes. As there is nearly no information available on tool-life for microforming the starting point was conventional cold forming. In cold forming common failures are (1) over stressing of the tool; (2) abrasive wear; (3) galling or adhesive wear, and (4) fatigue failure. The large variation in...

The wear of atomic force microscope (AFM) tips is a critical issue in the performance of probe-based metrology and nanomanufacturing processes. In this work, diamond-like carbon (DLC) was coated on Si AFM tips using a plasma ion implantation and deposition process. The mechanical integrity of these DLC-coated tips was compared to that of uncoated silicon tips through systematic nanoscale wear t...