Biomechanical comparison of three internal fixation configurations for low transcondylar fractures of the distal humerus

BackgroundWe aimed to evaluate the biomechanical stiffness and strength of different internal fixation configurations and find suitable treatment strategies for low transcondylar fractures of the distal humerus.Methods and materialsThirty 4^th generation composite humeri were used to create low transcondylar fracture models that were fixed by orthogonal and parallel double plates as well as posterolateral plate and medial screw (PPMS) configurations (n=10 in each group) using an anatomical locking compression plate-screw system and fully threaded medial cortical screws. Posterior bending (maximum 50 N), axial loading (maximum 200 N) and internal rotation (maximum 10 N·m) were tested, in that order, for each specimen. Stiffness under different biomechanical settings among different configurations were compared. Another 18 sets of fracture models were created using these three configurations (n=6 in each group) and the load to failure under axial loading among different configurations was compared.ResultsUnder posterior bending, the stiffness of parallel group was higher than orthogonal group (P<0.001), and orthogonal group was higher than PPMS group (P<0.001). Under axial loading, the stiffness of parallel group was higher than orthogonal group (P=0.001) and PPMS group (P<0.001); however, the difference between orthogonal and PPMS group was not statistically significant (P>0.05). Under internal rotation, the stiffness of parallel group was higher than orthogonal group (P=0.044), and orthogonal group was higher than PPMS group (P=0.029). In failure test under axial loading, the load to failure in the orthogonal group was lower than parallel group (P=0.009) and PPMS group (P=0.021), but the difference between parallel group and PPMS group was not statistically significant (P>0.05). All specimens in orthogonal group demonstrated “distal medial failure”; most specimens had “distal medial and trochlear failure” in the parallel group; most specimens exhibited “contact failure” in the PPMS group.ConclusionFor treating low transcondylar fractures, the overall stiffness and strength of the parallel configuration were superior to those of the orthogonal and PPMS configurations. Nevertheless, the PPMS configuration can provide adequate stability and stiffness comparable to double-plate configurations under axial loading. Therefore, the PPMS construct may have certain clinical value.     

The Impact of Testosterone on the QT Interval: A Systematic Review

Humans and mammals have sex-specific differences in cardiac electrophysiology, linked to the action of sex hormones in the cardiac muscle. These hormones can upregulate or downregulate the expression of ionic channels modulating the cardiac cycle through genomic and non-genomic interactions. Systematic search in PubMed, Medline and EMBASE including keywords pertaining to testosterone and QT interval. Included experimental studies and observation studies and case reports presenting the results of testosterone administration, excess or deficiency in humans and animals. Testosterone has been shown to shorten the action potential duration, by enhancing the expression of K⁺ channels and downregulating I_CaL increasing the repolarization reserve of the cardiac muscle. This effect has been observed in both genders and animals. Testosterone deficient states can promote arrhythmogenesis. The evidence in this paper may be used to guide clinical considerations, such as increased clinical surveillance of patients in testosterone deficient states using ECG.     

Bone Metabolism Discrepancy in Type 2 Diabetes Mellitus Patients With and Without Non-Alcoholic Fatty Liver Disease

To explore the distribution of several bone metabolic indicators in type 2 diabetes patients (T2DM) with and without non-alcoholic fatty liver disease (NAFLD) and to preliminarily evaluate the relationship of bone metabolism with NAFLD in patients with T2DM. The hospitalized patients with T2DM were divided into the group of T2DM complicated with NAFLD and the group of T2DM alone according to the results of ultrasonic diagnosis. The general information and laboratory test data such as bone metabolism indexes of these patients were collected and the differences of the indexes between the 2 groups were compared. Furthermore, the independent influencing factors of NAFLD in patients with T2DM were analyzed. A total of 186 patients were included in the study. Compared with patients with T2DM only, patients with T2DM combined with NAFLD were characterized with younger age (p < 0.001), higher BMI (p = 0.016), ALT (p = 0.001), TG (p = 0.005), HOMA-IR (p = 0.005), and lower HDL-C (p = 0.031). Significant discrepancy of age (OR 1.052, p = 0.001), ALT (OR 0.964, p = 0.047), HOMA-IR (OR 0.801, p = 0.005), and T-PINP (OR 1.022, p = 0.008) was found using multivariate logistic regression model. Significant discrepancy of T-PINP was found in T2DM patients with and without NAFLD. Further studies are needed to explore whether T-PINP could be used as a predictor of fatty liver disease, osteoporosis, and other related complications in patients with T2DM.     

Everyday footwear: An overview of what we know and what we should know on ill-fitting footwear and associated pain and pathology

Footwear has been used to protect feet for millennia with socially exclusive population adopting stylish and fashionable shoes with expensive materials. In terms of historic timeline, only more recently footwear has been worn by all classes in the western world as an integral part of their apparel. Traditionally, footwear has been constructed from natural materials, mainly leather, but has recently benefitted from the flexibility that technology has provided with a plethora materials and new design innovations. Although it has expanded the availability for a variety of consumers, the choice and fit continue to be problematic with many individuals wearing shoes that are ill-fitting. Provision of specific footwear advice for problem feet is poorly evidenced and is heavily practitioner dependant limiting its efficacy. There is limited understanding as to the changes that can occur from regularly wearing footwear that is unsuitable in shape, style and construction which is referred to as ill-fitting. Current research on the effect that everyday footwear has on foot function and pain focuses mainly on women’s shoes, particularly high heels. Defining what is a good fitting shoe, that does not damage the foot or mechanics of walking, may need to be individualised, but best fit is based on loose historical parameters rather than research evidence. The aim of this overview is to highlight aspects of current research, establishing what is known about the effect’s shoes have on the feet as well as exploring the mythology around footwear fit and advice that is often historical in nature.     

Infusions of Large Synthetic HDL Containing Trimeric apoA-I Stabilize Atherosclerotic Plaques in Hypercholesterolemic Rabbits

BackgroundAmong strategies to reduce the remaining risk of cardiovascular disease, interest has focused on using infusions of synthetic high-density lipoprotein (sHDL).MethodsNew Zealand rabbits underwent a perivascular injury at both carotids and were randomly allocated into 2 protocols: (1) a single-dose study, where rabbits were treated with a single infusion of sHDL containing a trimeric form of human apoA-I (TN-sHDL, 200 mg/kg) or with Placebo; (2) a multiple-dose study, where 4 groups of rabbits were treated 5 times with Placebo or TN-sHDL at different doses (8, 40, 100 mg/kg). Plaque changes were analysed in vivo by intravascular ultrasound. Blood was drawn from rabbits for biochemical analyses and cholesterol efflux capacity evaluation.ResultsIn both protocols, atheroma volume in the Placebo groups increased between the first and the second intravascular ultrasound evaluation. A stabilization or a slight regression was instead observed vs baseline in the TN-sHDL-treated groups (P < 0.005 vs Placebo after infusion). TN-sHDL treatment caused a sharp rise of plasma-free cholesterol levels and a significant increase of total cholesterol efflux capacity. Histologic analysis of carotid plaques showed a reduced macrophage accumulation in TN-sHDL-treated rabbits compared with Placebo (P < 0.05).ConclusionsOur results demonstrate that acute and subacute treatments with TN-sHDL are effective in stabilizing atherosclerotic plaques in a rabbit model. This effect appears to be related to a reduced intraplaque accumulation of inflammatory cells. Besides recent failures in proving its efficacy, sHDL treatment remains a fascinating therapeutic option for the reduction of cardiovascular risk.     

Effect of Dexmedetomidine infusion during hip fracture surgery on hemodynamic parameters and blood loss: A triple-blinded Randomized Clinical Trial

Introduction In this study, we aim to assess the intra-operative effect of dexmedetomidine administration on the hemodynamic parameters and bleeding volume during hip fracture surgery.Patients and methods we designed and implemented a triple-blinded randomized clinical trial to objectively compare the effects of 0.5 µg/kg/h infusion of dexmedetomidine with placebo (equal amount of normal saline) during hip fracture surgery. All included cases were between 30 and 70 years old and underwent surgery for fixation of a proximal femur fracture from September 26, 2020 until February 15, 2021. They were all ASA class I or II with preoperative hemoglobin levels of 10 mg/dL or higher. Surgical blood loss and hemodynamic parameters were documented.Results 76 patients were enrolled. There were no significant differences in baseline patient characteristics. The bleeding rate was 620 ± 190.0 mL for the normal saline group and 476 ± 177.98 mL in the dexmedetomidine group (P = 0.04). No significant effect on hemodynamic parameters was observed.Conclusion Based on the current study, intravenous infusion of dexmedetomidine during hip fracture surgery under general anesthesia reduced the amount of intraoperative bleeding without causing any significant hemodynamic disturbances.Registration number IRCT20191222045857N1 (Iranian Registry of Clinical Trials)     

Influenza vaccination and the endurance against air pollution among elderly with acute coronary syndrome

ObjectiveAir pollution, weather condition and influenza are known risk factors of acute coronary syndrome (ACS) among elderly people. The influenza vaccine (IV) has been shown to reduce major cardiovascular events. The purpose of this study was to compare resistance to air pollution and weather factors causing ACS between vaccinated and less-vaccinated elderly people.MethodsA case–crossover design was applied to 1835 elderly ACS patients who were obtained from the 1-million sample of Taiwan National Health Insurance Research Data with inclusion criteria: (1) the first diagnosis of ACS was in cold season and at age 68 or more, (2) had received the free IV program at least once during the period 3 years before the ACS. They were stratified into two groups: 707 had received flu vaccinations for all the 3 years and the remaining 1128 had not. The measurements of air pollutants, temperature, and humidity corresponding to each of the 3 days prior to the ACS diagnosis date were retrieved from the data banks of the Taiwan Environmental Protection Administration and Central Weather Bureau.FindingsIncreases in air pollution concentrations of CO, NO₂, PM₁₀ or PM_2.5 and decreases in temperature significantly influenced the risk of ACS for the non-continuously vaccinated elderly population; however, less significant effects were observed for the continuously vaccinated population.ConclusionConsecutive influenza vaccination may potentially offer resistance against the detrimental effects of air pollution and changes in temperature in frail elderly adults with ACS. Future studies are needed to directly assess the interaction effect between the vaccination and environmental factors on ACS.