Mechanical failure of cemented femoral total hip replacement

A review, with 17 refs. Factors which affect mech. failure of cemented femoral total hip replacement, i.e., external load, materials, geometry, and interfaces, are discussed

Fixation of the Cemented Stem: Clinical Relevance of the Porosity and Thickness of the Cement Mantle

The aim of this review paper is to define the fixation of the cemented stem. Polymethyl methacrylate, otherwise known as “bone cement”, has been used in the fixation of hip implants since the early 1960s. Sir John Charnley, the pioneer of modern hip replacement, incorporated the use of cement in the development of low frictional torque hip arthroplasty. In this paper, the concepts of femoral stem design and fixation, clinical results, and advances in understanding of the optimal use of cement are reviewed. The purpose of this paper is to help understanding and discussions on the thickness and the porosity of the cement mantle in total hip arthroplasty. Cement does not act as an adhesive, as sometimes thought, but relies on an interlocking fit to provide mechanical stability at the cement–bone interface, while at the prosthesis– cement interface it achieves stability by optimizing the fit of the implant in the cement mantle, such as in a tapered femoral stem

Polo kinase recruitment via the constitutive centromere-associated network at the kinetochore elevates centromeric RNA

The kinetochore, a multi-protein complex assembled on centromeres, is essential to segregate chromosomes during cell division. Deficiencies in kinetochore function can lead to chromosomal instability and aneuploidy-a hallmark of cancer cells. Kinetochore function is controlled by recruitment of regulatory proteins, many of which have been documented, however their function often remains uncharacterized and many are yet to be identified. To identify candidates of kinetochore regulation we used a proteome-wide protein association strategy in budding yeast and detected many proteins that are involved in post-translational modifications such as kinases, phosphatases and histone modifiers. We focused on the Polo-like kinase, Cdc5, and interrogated which cellular components were sensitive to constitutive Cdc5 localization. The kinetochore is particularly sensitive to constitutive Cdc5 kinase activity. Targeting Cdc5 to different kinetochore subcomplexes produced diverse phenotypes, consistent with multiple distinct functions at the kinetochore. We show that targeting Cdc5 to the inner kinetochore, the constitutive centromere-associated network (CCAN), increases the levels of centromeric RNA via an SPT4 dependent mechanism

Annual research review: harms experienced by child users of online and mobile technologies: the nature, prevalence and management of sexual and aggressive risks in the digital age

Aims and scope: The usage of mobile phones and the internet by young people has increased rapidly in the past decade, approaching saturation by middle childhood in developed countries. Besides many benefits, online content, contact or conduct can be associated with risk of harm; most research has examined whether aggressive or sexual harms result from this. We examine the nature and prevalence of such risks, and evaluate the evidence regarding the factors that increase or protect against harm resulting from such risks, so as to inform the academic and practitioner knowledge base. We also identify the conceptual and methodological challenges encountered in this relatively new body of research, and highlight the pressing research gaps. Methods: Given the pace of change in the market for communication technologies, we review research published since 2008. Following a thorough bibliographic search of literature from the key disciplines (psychology, sociology, education, media studies and computing sciences), the review concentrates on recent, high quality empirical studies, contextualizing these within an overview of the field. Findings: Risks of cyberbullying, contact with strangers, sexual messaging (‘sexting’) and pornography generally affect fewer than one in five adolescents. Prevalence estimates vary according to definition and measurement, but do not appear to be rising substantially with increasing access to mobile and online technologies, possibly because these technologies pose no additional risk to offline behaviour, or because any risks are offset by a commensurate growth in safety awareness and initiatives. While not all online risks result in self-reported harm, a range of adverse emotional and psychosocial consequences is revealed by longitudinal studies. Useful for identifying which children are more vulnerable than others, evidence reveals several risk factors: personality factors (sensation-seeking, low self-esteem, psychological difficulties), social factors (lack of parental support, peer norms) and digital factors (online practices, digital skills, specific online sites). Conclusions: Mobile and online risks are increasingly intertwined with pre-existing (offline) risks in children's lives. Research gaps, as well as implications for practitioners, are identified. The challenge is now to examine the relations among different risks, and to build on the risk and protective factors identified to design effective interventions

Impaction bone grafting of the glenoid in revision shoulder arthroplasty : classification, technical description and early results

Background Glenoid component fixation remains an issue in the long-term survival of total shoulder arthroplasty. As a consequence revision of the glenoid component is becoming increasingly more common and reconstructive techniques to preserve and restore bone stock are becoming more important.Methods In this article we describe the combined technique of impaction grafting and glenoid component exchange together with a classification of the glenoid defect with a report on four sequential cases in patients with rheumatoid arthritis with an average age of 56 years. The minimum follow-up was 34 months (range 34 months to 62 months).Results Patients reported excellent pain relief and some improvement in motion and function. The complication rate remains low. Radiological assessment using tomograms showed good incorporation of the bone graft and minimal signs of glenoid loosening.Conclusion The results of this study confirm that at least in the short term impaction grafting techniques used to reconstitute the glenoid in revision surgery can be successful.<br /