Fracture load for short versus standard cemented hip stems : an experimental in vitro study

Introduction: In an attempt to reduce stress shielding in the proximal femur multiple new shorter stem design have become available. We investigated the load to fracture of a new polished tapered cemented short stem in comparison to the conventional polished tapered Exeter stem. Method: A total of forty-two stems, twenty-one short stems and twenty-one conventional stems both with three different offsets were cemented in a composite sawbone model and loaded to fracture. Results: study showed that femurs will break at a significantly lower load to failure with a shorter compared to conventional length Exeter stem. Conclusion: This Both standard and short stem design are safe to use as the torque to failure is 7–10 times as much as the torques seen in activities of daily living.

Investigating the effect of internal fixation stiffness on metaphyseal fracture healing in a mouse model

This project examined the differences in healing of metaphyseal bone, when the implants of variable stiffness are used for fracture fixation. This knowledge is important in development of novel orthopaedic implants, used in orthopaedic surgery to stabilise the fractures. Dr Koval used a mouse model to create a fracture, and then assessed its healing with a combination of mechanical testing, microcomputed tomography and histomorphometric examination.

Clinically-based automatic implant fitting for shape optimization of fracture fixation plates

Complex bone contour and anatomical variations between individual bones complicate the process of deriving an implant shape that fits majority of the population. This thesis proposes an automatic fitting method for anatomically-precontoured plates based on clinical requirements, and investigated if 100% anatomical fit for a group of bone is achievable through manual bending of one plate shape. It was found that, for the plate used, 100% fit is impossible to achieve through manual bending alone. Rather, newly-developed shapes are also required to obtain anatomical fit in areas with more complex bone contour.

Development and validation of the ankle fracture outcome of rehabilitation measure (A-FORM)

Study Design Delphi panel and cohort study. Objective To develop and refine a condition-specific, patient-reported outcome measure, the Ankle Fracture Outcome of Rehabilitation Measure (A-FORM), and to examine its psychometric properties, including factor structure, reliability, and validity, by assessing item fit with the Rasch model. Background To our knowledge, there is no patient-reported outcome measure specific to ankle fracture with a robust content foundation. Methods A 2-stage research design was implemented. First, a Delphi panel that included patients and health professionals developed the items and refined the item wording. Second, a cohort study (n = 45) with 2 assessment points was conducted to permit preliminary maximum-likelihood exploratory factor analysis and Rasch analysis. Results The Delphi panel reached consensus on 53 potential items that were carried forward to the cohort phase. From the 2 time points, 81 questionnaires were completed and analyzed; 38 potential items were eliminated on account of greater than 10% missing data, factor loadings, and uniqueness. The 15 unidimensional items retained in the scale demonstrated appropriate person and item reliability after (and before) removal of 1 item (anxious about footwear) that had a higher-than-ideal outfit statistic (1.75). The “anxious about footwear” item was retained in the instrument, but only the 14 items with acceptable infit and outfit statistics (range, 0.5–1.5) were included in the summary score. Conclusion This investigation developed and refined the A-FORM (Version 1.0). The A-FORM items demonstrated favorable psychometric properties and are suitable for conversion to a single summary score. Further studies utilizing the A-FORM instrument are warranted. J Orthop Sports Phys Ther 2014;44(7):488–499. Epub 22 May 2014. doi:10.2519/jospt.2014.4980

Multiple criteria-based real-time decision making by autonomous city vehicles

This paper addresses the topic of real-time decision making for autonomous city vehicles, i.e. the autonomous vehicles’ ability to make appropriate driving decisions in city road traffic situations. After decomposing the problem into two consecutive decision making stages, and giving a short overview about previous work, the paper explains how Multiple Criteria Decision Making (MCDM) can be used in the process of selecting the most appropriate driving maneuver.

Expanded review criteria : the case of nonpharmacological interventions in dementia

This paper challenges the assumptions underlying many reviews and offers alternative criteria for examining evidence for nonpharmacological interventions. We evaluated 27 reviews examining interventions for persons with dementia as they relate to the issues of selection based on randomized controlled trial (RCT) design. Reviews were described by type of intervention, level of cognitive function, and criteria for inclusion. Of the 27 reviews, 46% required RCTs for inclusion and most had stringent inclusion criteria. This resulted in poor utilization of the literature and low ecological validity. Eliminating most of the available data poses a critical problem to clinical and research development. Studies meeting strict methodological criteria may not generalize to the greater population or may exclude sub-populations and interventions. Limitations of double-blind RCTs and potential design solutions are set forth based on appropriate populations, problems, interventions, and settings characteristics.

Temperature and strain-rate dependent fracture strength of graphynes

Graphyne is an allotrope of graphene. The mechanical properties of graphynes (α-, β-, γ- and 6,6,12-graphynes) under uniaxial tension deformation at different temperatures and strain rates are studied using molecular dynamics simulations. It is found that graphynes are more sensitive to temperature changes than graphene in terms of fracture strength and Young's modulus. The temperature sensitivity of the different graphynes is proportionally related to the percentage of acetylenic linkages in their structures, with the α-graphyne (having 100% of acetylenic linkages) being most sensitive to temperature. For the same graphyne, temperature exerts a more pronounced effect on the Young's modulus than fracture strength, which is different from that of graphene. The mechanical properties of graphynes are also sensitive to strain rate, in particular at higher temperatures.

Improving criteria and feedback in student assessment in law

Spurred on by both the 1987 Pearce Report1 and the general changes to higher education spawned by the “Dawkins revolution” from 1988, there has been much critical self-evaluation leading to profound improvements to the quality of teaching in Australian law schools.2 Despite the changes there are still areas of general law teaching practice which have lagged behind recent developments in our understanding of what constitutes high quality teaching. One such area is assessment criteria and feedback. The project Improving Feedback in Student Assessment in Law is an attempt to remedy this. It aims to produce a manual containing key principles for the design of assessment and the provision of feedback, with practical yet flexible ideas and illustrations which law teachers may adopt or modify. Most of the examples have been developed by teachers at the University of Melbourne Law School. The project was supported in 1996 by a Committee for the Advancement of University Teaching grant and the manual will be published late in 1997.3 This note summarises the core principles which are elaborated further in the manual.

Mathematical modelling of intramembranous bone formation during fracture healing

During fracture healing, many complex and cryptic interactions occur between cells and bio-chemical molecules to bring about repair of damaged bone. In this thesis two mathematical models were developed, concerning the cellular differentiation of osteoblasts (bone forming cells) and the mineralisation of new bone tissue, allowing new insights into these processes. These models were mathematically analysed and simulated numerically, yielding results consistent with experimental data and highlighting the underlying pattern formation structure in these aspects of fracture healing.

A systematic review of prescribing criteria to evaluate appropriateness of medications in frail older people

This study systematically reviews the published literature regarding inappropriate prescribing in frail individuals aged at least 65 years. Twenty-five of 466 identified studies met the inclusion criteria. All papers measured some surrogate indicators of frailty, such as performance-based tests, cognitive function and functional dependency. Beers criteria were used in 20 studies (74%) to evaluate inappropriate medication use and 36% (9/25) studies used more than one criterion. The prevalence of inappropriate medications ranged widely from 11 to 92%. Only a few studies reported the relationship between potentially inappropriate medication use and surrogate measures of frailty. These diverse findings indicate the need for a standardized measure for assessing appropriateness of medication in frail older individuals. Prescribing tools should address both medication and patient-related factors such as life expectancy and functional status to minimize inappropriate prescribing in frail individuals.

Investigating how designers collaborate and respond to sustainable design criteria

This research provides a critical link to ensure designers remain at the forefront of developing safe, sustainable and innovative products and services in the future. The four key findings of this research contribute to the advancement of knowledge and provide an understanding of the relationships between designers' co-evolution approach and their use of analogy. The behavioural relationships between sketching and gesture were investigated. The outcome of this research is a Design Activity Framework. This framework demonstrates a novel understanding how designers design by concentrating on co-evolution, problem-framing and solution seeking.

A method for optimal fit of patient-specific fracture fixation plates

Anatomically pre-contoured fracture fixation plates are a treatment option for bone fractures. A well-fitting plate can be used as a tool for anatomical reduction of the fractured bone. However, recent studies showed that some plates fit poorly for many patients due to considerable shape variations between bones of the same anatomical site. Therefore, the plates have to be manually fitted and deformed by surgeons to fit each patient optimally. The process is time-intensive and labor-intensive, and could lead to adverse clinical implications such as wound infection or plate failure. This paper proposes a new iterative method to simulate the patient-specific deformation of an optimally fitting plate for pre-operative planning purposes. We further demonstrate the validation of the method through a case study. The proposed method involves the integration of four commercially available software tools, Matlab, Rapidform2006, SolidWorks, and ANSYS, each performing specific tasks to obtain a plate shape that fits optimally for an individual tibia and is mechanically safe. A typical challenge when crossing multiple platforms is to ensure correct data transfer. We present an example of the implementation of the proposed method to demonstrate successful data transfer between the four platforms and the feasibility of the method.

Investigation of the effects of the fatty acid profile on fuel properties using a Multi-Criteria Decision Analysis

The structural features of fatty acids in biodiesel, including degree of unsaturation, percentage of saturated fatty acids and average chain length, influence important fuel properties such as cetane number, iodine value, density, kinematic viscosity, higher heating value and oxidation stability. The composition of fatty acid esters within the fuel should therefore be in the correct ratio to ensure fuel properties are within international biodiesel standards such as ASTM 6751 or EN 14214. This study scrutinises the influence of fatty acid composition and individual fatty acids on fuel properties. Fuel properties were estimated based on published equations, and measured according to standard procedure ASTM D6751 and EN 14214 to confirm the influences of the fatty acid profile. Based on fatty acid profile-derived calculations, the cetane number of the microalgal biodiesel was estimated to be 11.6, but measured 46.5, which emphasises the uncertainty of the method used for cetane number calculation. Multi-criteria decision analysis (MCDA), PROMETHEE-GAIA, was used to determine the influence of individual fatty acids on fuel properties in the GAIA plane. Polyunsaturated fatty acids increased the iodine value and had a negative influence on cetane number. Kinematic viscosity was negatively influenced by some long chain polyunsaturated fatty acids such as C20:5 and C22:6 and some of the more common saturated fatty acids C14:0 and C18:0. The positive impact of average chain length on higher heating value was also confirmed in the GAIA plane

Effects of anticoagulants on outcome of femoral neck fracture surgery

PURPOSE To review records of 330 patients who underwent surgery for femoral neck fractures with or without preoperative anticoagulation therapy. METHODS Medical records of 235 women and 95 men aged 48 to 103 years (mean, 81.6; standard deviation [SD], 13.1) who underwent surgery for femoral neck fractures with or without preoperative anticoagulation therapy were reviewed. 30 patients were on warfarin, 105 on aspirin, 28 on clopidogrel, and 167 were controls. The latter 3 groups were combined as the non-warfarin group and compared with the warfarin group. Hospital mortality, time from admission to surgery, length of hospital stay, return to theatre, and postoperative complications (wound infection, deep vein thrombosis, and pulmonary embolism) were assessed. RESULTS The warfarin and control groups were significantly younger than the clopidogrel and aspirin groups (80.8 vs. 80.0 vs. 84.2 vs. 83.7 years, respectively, p<0.05). 81% of the patients underwent surgery within 48 hours of admission. The overall mean time from admission to surgery was 1.8 days; it was longer in the warfarin than the aspirin, clopidogrel, and control groups (3.3 vs. 1.8 vs. 1.6 vs. 1.6 days, respectively, p<0.001). The mean length of hospital stay was 17.5 (SD, 9.6; range, 3-54) days. The overall hospital mortality was 3.9%; it was 6.7% in the warfarin group, 3.8% in the aspirin group, 3.6% in the clopidogrel group, and 3.6% in the control group (p=0.80). Four patients returned to theatre for surgery: one in the warfarin group for washout of a haematoma, 2 in the aspirin group for repositioning of a mal-fixation and for debridement of wound infection, and one in the control group for debridement of wound infection. The warfarin group did not differ significantly from non-warfarin group in terms of postoperative complication rate (6.7% vs. 2.7%, p=0.228) and the rate of return to theatre (3.3% vs. 1%, p=0.318). CONCLUSION It is safe to continue aspirin and clopidogrel prior to surgical treatment for femoral neck fracture. The risk of delaying surgery outweighs the peri-operative bleeding risk.