15 research outputs found
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
Ion homeostasis in the Chloroplast
peer reviewedThe chloroplast is an organelle of high demand for macro- and micro-nutrient ions, which are required for the maintenance of the photosynthetic process. To avoid deficiency while preventing excess, homeostasis mechanisms must be tightly regulated. Here, we describe the needs for nutrient ions in the chloroplast and briefly highlight their functions in the chloroplastidial metabolism. We further discuss the impact of nutrient deficiency on chloroplasts and the acclimation mechanisms that evolved to preserve the photosynthetic apparatus. We finally present what is known about import and export mechanisms for these ions. Whenever possible, a comparison between cyanobacteria, algae and plants is provided to add an evolutionary perspective to the description of ion homeostasis mechanisms in photosynthesis
A systematic review investigating the identification, causes, and outcomes of delays in the management of chronic limb-threatening ischemia and diabetic foot ulceration
Objectives Patients presenting with chronic limb threatening ischaemia (CLTI) and diabetic foot
ulceration (DFU) are at high risk of major lower limb amputation. Long-standing concern
exists regarding late presentation and delayed management contributing to increased
amputation rates. Despite multiple guidelines existing on the management of both conditions,
there is currently no accepted timeframe in which to enact specialist care and treatment. This
systematic review aims to investigate potential time delays in the identification, referral and
management of both CLTI and DFU. Methods A systematic review, conforming to the Preferred Reporting Items for Systematic Review of
Meta-Analysis (PRISMA) statement standards, was performed searching MEDLINE, Embase,
The Cochrane Library and CINAHL from inception to 14 13 th November 2018. All English
language qualitative and quantitative articles investigating or reporting the identification,
causes and outcomes of time delays within ‘high income’ countries (annual gross domestic
product per person >$15,000) were included. Data were extracted independently by the
investigators. Given the clinical cross-over, both conditions were investigated together. A study
protocol was designed and registered at the International Prospective Register of Systematic
Reviews (PROSPERO) (registration number: CRD42018115286). Results A total of 4780 articles were screened, of which 32 articles, involving 71,310 patients and
1,388 healthcare professionals were included. Twenty-three articles focussed predominantly
on DFU. Considerable heterogeneity was noted and only 12 articles were deemed of high
quality. Only 4 articles defined a ‘delay’ however this was not consistent between studies.
Median times from symptom onset to specialist healthcare assessment ranged from 15 to 126
days with subsequent median times from assessment to treatment ranging from 1 to 91 days.
A number of patient and healthcare factors were consistently reported as potentially causative
including, poor patient symptom recognition, inaccurate healthcare assessment and difficulties
in accessing specialist services. Twenty articles reported outcomes of delays, namely rates of
major amputation, ulcer healing and all-cause mortality. Although results were heterogeneous,
they elude to delays being associated with detrimental outcomes for patients.
Conclusions Time delays exist in all aspects of the management pathway, which are in some cases
considerable in length. The causes of these are complex but reflect poor patient health-seeking
behaviours, inaccurate healthcare assessment and barriers to referral and treatment within the
care pathway. The adoption of standardised limits for referral and treatment times, exploration
of missed opportunities for diagnosis and investigation of novel strategies for providing
specialist care are required to help reduce delays.</div