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A novel sideways fall simulator to study hip fractures ex vivo.

ABSTRACT: Falls to the side are the leading cause of hip fractures in the elderly. The load that a person experiences during a fall cannot be measured with volunteers for ethical reasons. To evaluate injurious loads, while considering relevant energy input and body posture for a sideways fall, a subject-specific cadaveric impact experiment was developed. Full cadaveric femur-pelvis constructs (N = 2) were embedded in surrogate soft tissue material and attached to metallic surrogate lower limbs. The specimens were then subjected to an inverted pendulum motion, simulating a fall to the side with an impact to the greater trochanter. The load at the ground and the deformation of the pelvis were evaluated using a 6-axis force transducer and two high-speed cameras. Post-test, a trauma surgeon (PG) evaluated specimen injuries. Peak ground contact forces were 7132 N and 5641 N for the fractured and non-fractured specimen, respectively. We observed a cervical fracture of the femur in one specimen and no injuries in a second specimen, showing that the developed protocol can be used to differentiate between specimens at high and low fracture risk.

SUBMITTER: Fleps I

PROVIDER: S-EPMC6057661 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

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A novel sideways fall simulator to study hip fractures ex vivo.

Fleps Ingmar I Vuille Muriel M Melnyk Angela A Ferguson Stephen J SJ Guy Pierre P Helgason Benedikt B Cripton Peter A PA

PloS one 20180724 7

Falls to the side are the leading cause of hip fractures in the elderly. The load that a person experiences during a fall cannot be measured with volunteers for ethical reasons. To evaluate injurious loads, while considering relevant energy input and body posture for a sideways fall, a subject-specific cadaveric impact experiment was developed. Full cadaveric femur-pelvis constructs (N = 2) were embedded in surrogate soft tissue material and attached to metallic surrogate lower limbs. The specim ...[more]

PMID: 30040858

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Project description:In this large population-based matched cohort study, patients with primary aldosteronism were at increased risk of hip fracture, particularly subgroups traditionally considered at higher risk of osteoporosis such as women, patients older than 56 years at diagnosis, patients with established cardiovascular disease at diagnosis, and patients treated with MRA.PurposePrevious studies suggest that primary aldosteronism (PA) is associated with dysregulated bone homeostasis. The aim of this study was to evaluate the incidence of hip fractures in patients with PA.MethodsWe studied a nationwide cohort of 2419 patients with PA (1997-2019) and 24 187 age and sex matched controls from the general population. Hip fractures were identified by ICD codes in the Swedish National Patient Register. We estimated hazard ratios (HRs) for incident hip fractures, adjusted for prior fractures, socioeconomic factors, diabetes, osteoporosis, hyperparathyroidism, and cardiovascular disease (CVD). Pairwise subgroup comparisons were performed by age (18-56 and > 56 years), sex, CVD at baseline, and treatment for PA.ResultsDuring a mean follow up of 8 ± 5 years, 64 (2.6%) patients had a hip fracture after being diagnosed with PA, compared to 401 (1.7%) controls. After adjustments, PA was associated with a 55% increased risk of hip fracture compared to controls (HR 1.55 [1.18-2.03]). HRs were increased in women (HR 1.76 [95% CI 1.24-2.52]), patients aged > 56 years (HR 1.62 [95% CI 1.21-2.17]), and patients with CVD at diagnosis (HR 2.15 [95% CI 1.37-3.37]). PA patients treated with adrenalectomy did not have higher risk than controls (HR 0.84 [95% CI 0.35-2.0]), while patients treated with mineralocorticoid receptor antagonists (MRA) retained a greater risk (HR 1.84 [95% CI 1.20-2.83]).ConclusionPA is associated with increased hip fracture risk, especially in women, patients diagnosed after the age of 56 years and patients with established CVD at diagnosis. Also, patients treated with MRA seem to have an increased risk of hip fractures, while adrenalectomy may be protective.

Project description:Perivascular adipose tissue (PVAT) is increasingly recognized as an essential layer of the functional vasculature, being responsible for producing vasoactive substances and assisting arterial stress relaxation. Here, we test the hypothesis that PVAT reduces aortic stiffness. Our model was the thoracic aorta of the male Sprague-Dawley rat. Uniaxial mechanical tests for three groups of tissue were performed: aorta with PVAT attached (+PVAT) or removed (-PVAT), and isolated PVAT (PVAT only). The output of the mechanical test is reported in the form of a Cauchy stress-stretch curve. This work presents a novel, physiologically relevant approach to measure mechanical stiffness ex vivo in isolated PVAT. Low-stress stiffness (E0), high-stress stiffness (E1), and the stress corresponding to a stretch of 1.2 (σ1.2) were measured as metrics of distensibility. The low-stress stiffness was largest in the -PVAT samples and smallest in PVAT only samples. Both the high-stress stiffness and the stress at 1.2 stretch were significantly higher in -PVAT samples when compared with +PVAT samples. Taken together, these results suggest that -PVAT samples are stiffer (less distensible) both at low stress (not significant) as well as at high stress (significant) when compared with +PVAT samples. These conclusions are supported by the results of the continuum mechanics material model that we also used to interpret the same experimental data. Thus, tissue stiffness is significantly lower when considering PVAT as part of the aortic wall. As such, PVAT should be considered as a target for improving vascular function in diseases with elevated aortic stiffness, including hypertension.NEW & NOTEWORTHY We introduce a novel and physiologically relevant way of measuring perivascular adipose tissue (PVAT) mechanical stiffness which shows that PVAT's low, yet measurable, stiffness is linearly correlated with the amount of collagen fibers present within the tissue. Including PVAT in the measurement of the aortic wall's mechanical behavior is important, and it significantly affects the resulting metrics by decreasing aortic stiffness.

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A novel sideways fall simulator to study hip fractures ex vivo.

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A novel sideways fall simulator to study hip fractures ex vivo.

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