Surgical site infection prevention following total hip arthroplasty in Australia : a cost-effectiveness analysis

Background: Surgical site infection (SSI) is associated with substantial costs for health services, reduced quality of life, and functional outcomes. The aim of this study was to evaluate the cost-effectiveness of strategies claiming to reduce the risk of SSI in hip arthroplasty in Australia. Methods: Baseline use of antibiotic prophylaxis (AP) was compared with no antibiotic prophylaxis (no AP), antibiotic-impregnated cement (AP þ ABC), and laminar air operating rooms (AP þ LOR). A Markov model was used to simulate long-term health and cost outcomes of a hypothetical cohort of 30,000 total hip arthroplasty patients from a health services perspective. Model parameters were informed by the best available evidence. Uncertainty was explored in probabilistic sensitivity and scenario analyses. Results: Stopping the routine use of AP resulted in over Australian dollars (AUD) $1.5 million extra costs and a loss of 163 quality-adjusted life years (QALYs). Using antibiotic cement in addition to AP (AP þ ABC)generated an extra 32 QALYs while saving over AUD $123,000. The use of laminar air operating rooms combined with routine AP (AP þ LOR) resulted in an AUD $4.59 million cost increase and 127 QALYs lost compared with the baseline comparator. Conclusion: Preventing deep SSI with antibiotic prophylaxis and antibiotic-impregnated cement has shown to improve health outcomes among hospitalized patients, save lives, and enhance resource allocation. Based on this evidence, the use of laminar air operating rooms is not recommended.

The results of acetabular impaction grafting in 129 primary cemented total hip arthroplasties

Between 1995 and 2003, 129 cemented primary THRs were performed using full acetabular impaction grafting to reconstruct acetabular deficiencies. These were classified as cavitary in 74 and segmental in 55 hips. Eighty-one patients were reviewed at mean 9.1 (6.2-14.3) years post-operatively. There were seven acetabular component revisions due to aseptic loosening, and a further 11 cases that had migrated >5mm or tilted >5° on radiological review - ten of which reported no symptoms. Kaplan-Meier analysis of revisions for aseptic loosening demonstrates 100% survival at nine years for cavitary defects compared to 82.6% for segmental defects. Our results suggest that the medium-term survival of this technique is excellent when used for purely cavitary defects but less predictable when used with large rim meshes in segmental defects.

Varianza analitica y aproximada del costo total de un proyecto

La varianza estadística del costo total de un proyecto usualmente se estima por medio de la simulación de Monte Carlo, bajo el supuesto de que los acercamientos analíticos son demasiado complicados. Este artículo analiza este supuesto y muestra que, contrario a lo esperado, la solución analítica es relativamente directa. También se muestra que el coeficiente de variación no se ve afectado por el tamaño (área superficial) del proyecto cuando se usan los costos de los componentes estandarizados. Se provee un caso de estudio en el cual se analizan los costos reales de los componentes para obtener la varianza del costo total requerida. Los resultados confirman trabajos previos al mostrar que la aproximación del segundo momento (varianza) bajo el supuesto de independencia subestima considerablemente el valor exacto. El análisis continua examinando los efectos del juicio profesional y con los datos simulados utilizados, la aproximación resulta razonablemente exacta - el juicio profesional absorbe la mayor parte de las intercorrelaciones involucradas. También se da un ejemplo en el cual las cantidades de los componentes unitarios son valoradas por sus costos unitarios promedios y muestra, una vez más, que la aproximación es cercana al valor real. Finalmente, el trabajo se extiende mostrando cómo obtener, para cada proyecto, las varianzas exactas del costo total.

Rapid quantification of methamphetamine: using Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Chemometrics

In Australia and increasingly worldwide, methamphetamine is one of the most commonly seized drugs analysed by forensic chemists. The current well-established GC/MS methods used to identify and quantify methamphetamine are lengthy, expensive processes, but often rapid analysis is requested by undercover police leading to an interest in developing this new analytical technique. Ninety six illicit drug seizures containing methamphetamine (0.1% - 78.6%) were analysed using Fourier Transform Infrared Spectroscopy with an Attenuated Total Reflectance attachment and Chemometrics. Two Partial Least Squares models were developed, one using the principal Infrared Spectroscopy peaks of methamphetamine and the other a Hierarchical Partial Least Squares model. Both of these models were refined to choose the variables that were most closely associated with the methamphetamine % vector. Both of the models were excellent, with the principal peaks in the Partial Least Squares model having Root Mean Square Error of Prediction 3.8, R2 0.9779 and lower limit of quantification 7% methamphetamine. The Hierarchical Partial Least Squares model had lower limit of quantification 0.3% methamphetamine, Root Mean Square Error of Prediction 5.2 and R2 0.9637. Such models offer rapid and effective methods for screening illicit drug samples to determine the percentage of methamphetamine they contain.

Metal ion levels post unilateral primary Exeter total hip replacement

There has been much discussion and controversy in the media recently regarding metal toxicity following large head metal on metal (MoM) total hip replacement (THR). Patients have been reported as having hugely elevated levels of metal ions with, at times, devastating systemic, neurolgical and/or orthopaedic sequelae. However, no direct correlation between metal ion level and severity of metallosis has yet been defined. Normative levels of metal ions in well functioning, non Cobalt-Chrome hips have also not been defined to date. The Exeter total hip replacement contains no Cobalt-Chrome (Co-Cr) as it is made entirely from stainless steel. However, small levels of these metals may be present in the modular head of the prosthesis, and their effect on metal ion levels in the well functioning patient has not been investigated. We proposed to define the “normal” levels of metal ions detected by blood test in 20 well functioning patients at a minimum 1 year post primary Exeter total hip replacement, where the patient had had only one joint replaced. Presently, accepted normal levels of blood Chromium are 10–100 nmol/L and plasma Cobalt are 0–20 nmol/L. The UK Modern Humanities Research Association (MHRA) has suggested that levels of either Cobalt or Chromium above 7 ppb (equivalent to 135 nmol/L for Chromium and 120 nmol/L for Cobalt) may be significant. Below this level it is indicated that significant soft tissue reaction and tissue damage is less likely and the risk of implant failure is reduced. Hips were a mixture of cemented and hybrid procedures performed by two experienced orthopaedic consultants. Seventy percent were female, with a mixture of head sizes used. In our cohort, there were no cases where the blood Chromium levels were above the normal range, and in more than 70% of cases, levels were below recordable levels. There were also no cases of elevated plasma Cobalt levels, and in 35% of cases, levels were negligible. We conclude that the implantation with an Exeter total hip replacement does not lead to elevation of blood metal ion levels.

The Imperial War Museum's social interpretation project

This report represents the output from research undertaken by University of Salford and MTM London as part of the joint Digital R&D Fund for Arts and Culture, operated by Nesta, Arts Council England and the AHRC. University of Salford and MTM London received funding from the programme to act as researchers on the Social Interpretation (SI) project, which was led by the Imperial War Museum (IWM) and their technical partners, The Centre for Digital Humanities, University College London, Knowledge Integration, and Gooii. The project was carried out between October 2011 and October 2012.

Most relevant strategies for preventing surgical site infection after total hip arthroplasty : guideline recommendations and expert opinion

BACKGROUND: Numerous strategies are available to prevent surgical site infections in hip arthroplasty, but there is no consensus on which might be the best. This study examined infection prevention strategies currently recommended for patients undergoing hip arthroplasty. METHODS: Four clinical guidelines on infection prevention/orthopedics were reviewed. Infection control practitioners, infectious disease physicians, and orthopedic surgeons were consulted through structured interviews and an online survey. Strategies were classified as "highly important" if they were recommended by at least one guideline and ranked as significantly or critically important by >/=75% of the experts. RESULTS: The guideline review yielded 28 infection prevention measures, with 7 identified by experts as being highly important in this context: antibiotic prophylaxis, antiseptic skin preparation of patients, hand/forearm antisepsis by surgical staff, sterile gowns/surgical attire, ultraclean/laminar air operating theatres, antibiotic-impregnated cement, and surveillance. Controversial measures included antibiotic-impregnated cement and, considering recent literature, laminar air operating theatres. CONCLUSIONS: Some of these measures may already be accepted as routine clinical practice, whereas others are controversial. Whether these practices should be continued for this patient group will be informed by modeling the cost-effectiveness of infection prevention strategies. This will allow predictions of long-term health and cost outcomes and thus inform decisions on how to best use scarce health care resources for infection control.

The use of navigation to achieve soft tissue balance in total knee arthroplasty : a randomised clinical study

Background: Achieving soft tissue balance is an operative goal in total knee arthroplasty. This randomised, prospective study compared computer navigation to conventional techniques in achieving soft tissue balance. Methods: Forty one consecutive knee arthroplasties were randomised to either a non-navigated or navigated group. In the non-navigated group, balancing was carried out using surgeon judgement. In the navigated group, balancing was carried out using navigation software. In both groups, the navigation software was used as a measuring tool. Results: Balancing of the mediolateral extension gap was superior in the navigation group (p=0.001). No significant difference was found between the two groups in balancing the mediolateral flexion gap or in achieving equal flexion and extension gaps. Conclusions: Computer navigation offered little advantage over experienced surgeon judgement in achieving soft tissue balance in knee replacement. However, the method employed in the navigated group did provide a reproducible and objective assessment of flexion and extension gaps and may therefore benefit surgeons in training.

Industrial land price and its impact on urban growth : a Chinese case study

China is experiencing rapid progress in industrialization, with its own rationale toward industrial land development based on a deliberate change from an extensive to intensive form of urban land use. One result has been concerted attempts by local government to attract foreign investment by a low industrial land price strategy, which has resulted in a disproportionally large amount of industrial land within the total urban land use structure at the expense of the urban sprawl of many cities. This paper first examines “Comparable Benchmark Price as Residential land use” (CBPR) as the theoretical basis of the low industrial land price phenomenon. Empirical findings are presented from a case study based on data from Jinyun County, China. These data are analyzed to reveal the rationale of industrial land price from 2000 to 2010 concerning the CBPR model. We then explore the causes of low industrial land prices in the form of a “Centipede Game Model”, involving two neighborhood regions as “major players” to make a set of moves (or strategies). When one of the players unilaterally reduces the land price to attract investment with the aim to maximize profits arising from the revenues generated from foreign investment and land premiums, a two-player price war begins in the form of a dynamic game, the effect of which is to produce a downward spiral of prices. In this context, the paradox of maximizing profits for each of the two players are not accomplished due to the inter-regional competition of attracted investment leading to a lose-lose situation for both sides’ in competing for land premium revenues. A short-term solution to the problem is offered involving the establishment of inter-regional cooperative partnerships. For the longer term, however, a comprehensive reform of the local financial system, more adroit regional planning and an improved means of evaluating government performance is needed to ensure the government's role in securing pubic goods is not abandoned in favor of one solely concerned with revenue generation.

NSAM-derived total surface area vs. SMPS-derived "mobility equivalent" surface area for different environmentally relevant aerosols

The surface area of inhaled particles deposited in the alveolar region, as reported by the TSI nanoparticle surface area monitor (NSAM), was compared with the corresponding value estimated by a TSI scanning mobility particle sizer (SMPS) for a range of environmentally relevant aerosols, including petrol emissions, ETS, laser printer emissions, cooking emissions and ambient aerosols. The SMPS values were based on a mobility size distribution assuming spherical particles using the appropriate size-dependent alveolar-deposition factors provided by the ICRP. In most cases, the two instruments showed good linear agreement. With petrol emissions and ETS, the linearity extended to over 103 μm2 cm-3. With printer emissions, there was good linearity up to about 300 μm2 cm-3 while the NSAM increasingly overestimated the surface area at higher concentrations. The presence of a nucleation event in ambient air caused the NSAM to over-estimate the surface area by a factor of 2. We summarize these results and conclude that the maximum number concentration up to which the NSAM is accurate clearly depends on the type of aerosol being sampled and provide guidance for the use of the instrument.

Postprandial total and HMW adiponectin following a high-fat meal in lean, obese and diabetic men

BACKGROUND/OBJECTIVES: Recent work suggests that macronutrients are pro-inflammatory and promote oxidative stress. Reports of postprandial regulation of total adiponectin have been mixed, and there is limited information regarding postprandial changes in high molecular weight (HMW) adiponectin. The aim of this study was to assess the effect of a standardised high-fat meal on metabolic variables, adiponectin (total and HMW), and markers of inflammation and oxidative stress in: (i) lean, (ii) obese non-diabetic and (iii) men with type 2 diabetes mellitus (T2DM). SUBJECTS/METHODS: Male subjects: lean (n=10), obese (n=10) and T2DM (n=10) were studied for 6 h following both a high-fat meal and water control. Metabolic variables (glucose, insulin, triglycerides), inflammatory markers (interleukin-6 (IL6), tumour necrosis factor (TNF)α, high-sensitivity C-reactive protein (hsCRP), nuclear factor (NF)κB expression in peripheral blood mononuclear cells (p65)), indicators of oxidative stress (oxidised low density lipoprotein (oxLDL), protein carbonyl) and adiponectin (total and HMW) were measured. RESULTS: No significant changes in TNFα, p65, oxLDL or protein carbonyl concentrations were observed. Overall, postprandial IL6 decreased in subjects with T2DM but increased in lean subjects, whereas hsCRP decreased in the lean cohort and increased in obese subjects. There was no overall postprandial change in total or HMW adiponectin in any group. Total adiponectin concentrations changed over time following the water control, and the response was significantly different in lean subjects compared with subjects with T2DM (P=0.04). CONCLUSIONS: No consistent significant postprandial inflammation, oxidative stress or regulation of adiponectin was observed in this study. Findings from the water control suggest differential basal regulation of total adiponectin in T2DM compared with lean controls.

Complications of perioperative warfarin therapy in total knee arthroplasty

Patients presenting for knee replacement on warfarin for medical reasons often require higher levels of anticoagulation peri-operatively than primary thromboprophylaxis and may require bridging therapy with heparin. We performed a retrospective case control study on 149 consecutive primary knee arthroplasty patients to investigate whether anti-coagulation affected short-term outcomes. Specific outcome measures indicated significant increases in prolonged wound drainage (26.8% of cases vs 7.3% of controls, p<0.001); superficial infection (16.8% vs 3.3%, p<0.001); deep infection (6.0% vs 0%, p<0.001); return-to-theatre for washout (4.7% vs 0.7%, p=0.004); and revision (4.7% vs 0.3%, p=0.001). Management of patients on long-term warfarin therapy following TKR is particularly challenging, as the surgeon must balance risk of thromboembolism against post-operative complications on an individual patient basis in order to optimise outcomes.

Anatomic fitting of total artificial hearts for in vivo evaluation

Successful anatomic fitting of a total artificial heart (TAH) is vital to achieve optimal pump hemodynamics after device implantation. Although many anatomic fitting studies have been completed in humans prior to clinical trials, few reports exist that detail the experience in animals for in vivo device evaluation. Optimal hemodynamics are crucial throughout the in vivo phase to direct design iterations and ultimately validate device performance prior to pivotal human trials. In vivo evaluation in a sheep model allows a realistically sized representation of a smaller patient, for which smaller third-generation TAHs have the potential to treat. Our study aimed to assess the anatomic fit of a single device rotary TAH in sheep prior to animal trials and to use the data to develop a threedimensional, computer-aided design (CAD)-operated anatomic fitting tool for future TAH development. Following excision of the native ventricles above the atrio-ventricular groove, a prototype TAH was inserted within the chest cavity of six sheep (28–40 kg).Adjustable rods representing inlet and outlet conduits were oriented toward the center of each atrial chamber and the great vessels, with conduit lengths and angles recorded for future analysis. A threedimensional, CAD-operated anatomic fitting tool was then developed, based on the results of this study, and used to determine the inflow and outflow conduit orientation of the TAH. The mean diameters of the sheep left atrium, right atrium, aorta, and pulmonary artery were 39, 33, 12, and 11 mm, respectively. The center-to-center distance and outer-edge-to-outer-edge distance between the atria, found to be 39 ± 9 mm and 72 ± 17 mm in this study, were identified as the most critical geometries for successful TAH connection. This geometric constraint restricts the maximum separation allowable between left and right inlet ports of a TAH to ensure successful alignment within the available atrial circumference.

Using technology to change adult sedentary behaviour, physical activity levels and total wellness

This thesis studied technology’s role in promoting and supporting active lifestyles through behavioural strategies to reduce sedentary time and increase physical activity. The five studies included (1) development of a self-report instrument quantifying daily sedentary behaviour and light-intensity physical activity; (2) establishment of instrument validity and reliability; (3) use of an online personal activity monitor to successfully reduce sedentary time and increase physical activity; (4) identification of positive differences in total wellness as related to high/low levels of sitting time combined with insufficient/sufficient physical activity; and (5) improvement of total wellness through positive changes in sedentary behaviour and physical activity.

Physical activity, sedentary behavior and total wellness changes among sedentary adults : a 4-week randomized controlled trial

Background The construct of total wellness includes a holistic approach to the body, mind and spirit components of life. While the health benefits of reducing sedentary behavior and increasing physical activity are well documented, little is known about the influence on total wellness of an internet-based physical activity monitor designed to help people to achieve higher physical activity levels. Purpose The purpose of this four-week, personal activity monitor-based intervention program was to reduce sedentary behavior and increase physical activity levels in daily living for sedentary adults and to determine if these changes would also be associated with improvement in total wellness. Methods Twenty-two men and 11 women (27 years ± 4.0) were randomly assigned to either an intervention (n = 18) or control group (n = 15). The intervention group interacted with an online personal activity monitor (Gruve Solution™) designed to reduce sedentary time and increase physical activity during activities of daily living. The control group did not interact with the monitor, as they were asked to follow their normal daily physical activities and sedentary behavior routines. The Wellness Evaluation of Lifestyle (WEL) inventory was used to assess total wellness. Sedentary time, light, walking, moderate and vigorous intensity physical activities were assessed for both intervention and control groups at baseline and at week-4 by the 7-day Sedentary and Light Intensity Physical Activity Log (7-day SLIPA Log) and the International Physical Activity Questionnaire (IPAQ). Results Significant increases in pre-post total wellness scores (from 64% ± 5.7 to 75% ± 8.5) (t (17) = -6.5, p < 0.001) were observed in the intervention group by the end of week four. Intervention participants decreased their sedentary time (21%, 2.3 hours/day) and increased their light (36.7%, 2.5 hours/day), walking (65%, 1057 MET-min/week), moderate (67%, 455 MET-min/week) and vigorous intensity (60%, 442 MET-min/week) physical activity (all p < 0.001). No significant differences for total wellness were observed between the groups at baseline and no pre-post significant differences were observed for any outcome variable in the control group. Conclusion Total wellness is improved when sedentary, but sufficiently physically active adults, reduce sedentary time and increase physical activity levels (i.e. light, walking, moderate and vigorous).