INTRODUCTION Catastrophic polyethylene failure is a rare complication of ceramic-on-polyethylene total hip arthroplasty due to the favorable tribological characteristics of ceramic. Failure of the polyethylene liner can be disastrous, increasing periprosthetic osteolysis, metallosis, and risk of dislocation. Complications associated with ceramic-on-polyethylene articulations have been studied e...

BACKGROUND Wear cannot be completely prevented after total hip arthroplasty. If severe polyethylene (PE) liner wear develops, the so-called catastrophic failure occurs and metallosis develops. We postulated that longevity of the new implant may be affected after revision surgery for metallosis following a catastrophic failure of a PE liner due to the substantial amount of PE wear particles and ...

We examined radiographic polyethylene wear in 233 cemented total hip arthroplasties (201 patients) with either a metal-backed or a non-metal-backed acetabular cup. All patients had identical cemented one-piece titanium femoral stems with a femoral head diameter of 28 mm. The mean linear wear rate was 0.11 mm/yr in metal-backed sockets and 0.08 mm/yr in non-metal-backed sockets (p = 0.0002). The...

Abstract: The detection of tool failure is crucial point in intelligent manufacturing. The lifetime of large cutting tools can be forecasted but the failure of small sized tools is nearly unpredictable. A number of signatures accompanying excess wear or emerging failure are investigated. The application of sensor fusion by means of neural networks to the monitoring of small drills is described ...

juanita hernandez is an 18-month-old hispanic, the younger of two children. juanita was at the 25th percentile for height and weight at birth, but both measurements fell to just below the 5th percentile during her first year. for the last 6 months however, her rate of growth has been normal and her height and weight curves lie parallel to just below the 5th percentile. juanita appears quite sma...

Steel composites reinforced with alumina nanoparticles were prepared by powder metallurgy process. Samples containing two different amounts of carbon (0.35 and 0.55 wt.%) and 0-5 wt.% Al2O3 nanoparticles were fabricated by mixing, compacting and sintering of diffusion bonded Distaloy AE powder. The density, hardness and wear tests were performed on the prepared samples. Fu...

During the last two decades, improvements in hip and knee designs, bearing materials, sterilisation techniques, oxidation stabilisation, and articulating surface treatments have led to superior performance of total hip and knee arthroplasties by reducing the prevalence of wear, delamination, and structural material fatigue. These advances are expected to show substantial benefits in decreasing ...

There is widespread concern regarding the incidence of adverse soft-tissue reactions after metal-on-metal (MoM) hip replacement. Recent National Joint Registry data have shown clear differences in the rates of failure of different designs of hip resurfacing. Our aim was to update the failure rates related to metal debris for the Articular Surface Replacement (ASR). A total of 505 of these were ...

  Background and Objective: Failure to thrive (FTT) is a sign that describes a particular problem rather than a diagnosis and explain growth failure or more advanced failure to gain weight appropriately. The aim of this study was to determine the prevalence and type of chromosomal abnormalities in patients presented with FTT. Materials and Method: One hundred FTT cases with clinical impressio...

In gears running under conditions of high load and low circumferential speed the lubricant film thickness is often not sufficient to fully separate the mating surfaces. Wear of the gear flanks can occur and can even result in total gear failure. For a given gear geometry the main influencing parameters are load, circumferential speed and lubricant. The wear characteristics of lubricants depend ...