Orthopaedic Basic Science Journal Scan

Related Articles

MOSHFIT: Algorithms for occlusion-tolerant mean shape and rigid motion from 3D movement data.

J Biomech. 2013 Jul 23;

Authors: Mitchelson JR

Abstract

Related Articles

The effects of core muscle activation on dynamic trunk position and knee abduction moments: Implications for ACL injury.

J Biomech. 2013 Jul 23;

Authors: Jamison ST, McNally MP, Schmitt LC, Chaudhari AM

Abstract

Related Articles

Newtonian and non-Newtonian blood flow in coiled cerebral aneurysms.

J Biomech. 2013 Jul 23;

Authors: Morales HG, Larrabide I, Geers AJ, Aguilar ML, Frangi AF

Abstract
Endovascular coiling aims to isolate the aneurysm from blood circulation by altering hemodynamics inside the aneurysm and triggering blood coagulation. Computational fluid dynamics (CFD) techniques have the potential to predict the post-operative hemodynamics and to investigate the complex interaction between blood flow and coils. The purpose of this work is to study the influence of blood viscosity on hemodynamics in coiled aneurysms. Three image-based aneurysm models were used. Each case was virtually coiled with a packing density of around 30%. CFD simulations were performed in coiled and untreated aneurysm geometries using a Newtonian and a Non-Newtonian fluid models. Newtonian fluid slightly overestimates the intra-aneurysmal velocity inside the aneurysm before and after coiling. There were numerical differences between fluid models on velocity magnitudes in coiled simulations. Moreover, the non-Newtonian fluid model produces high viscosity (>0.007 [Pas]) at aneurysm fundus after coiling. Nonetheless, these local differences and high-viscous regions were not sufficient to alter the main flow patterns and velocity magnitudes before and after coiling. To evaluate the influence of coiling on intra-aneurysmal hemodynamics, the assumption of a Newtonian fluid can be used.

Related Articles

Estimation of external contact loads using an inverse dynamics and optimization approach: General method and application to sit-to-stand maneuvers.

J Biomech. 2013 Jul 23;

Authors: Robert T, Causse J, Monnier G

Abstract

Related Articles

Influence of weak hip abductor muscles on joint contact forces during normal walking: probabilistic modeling analysis.

J Biomech. 2013 Jul 24;

Authors: Valente G, Taddei F, Jonkers I

Abstract

Related Articles

Development of a general method for designing microvascular networks using distribution of wall shear stress.

J Biomech. 2013 Jul 24;

Authors: Sayed Razavi M, Shirani E

Abstract

Kinetic sensitivity of a new lumbo-pelvic model to variation in segment parameter input.

J Appl Biomech. 2013 Jun;29(3):354-9

Authors: Crewe H, Campbell A, Elliott B, Alderson J

Abstract
This study aimed to assess variability in lumbo-pelvic forces and moments during a dynamic high-impact activity (cricket fast bowling) when calculated using different body segment parameters (BSPs). The first three BSPs were estimated using methods where the trunk was divided into segments according to nonspinal anatomical landmarks. The final approach defined segment boundaries according to vertebral level. Three-dimensional motion analysis data from nine male cricketers' bowling trials were processed using the four BSPs. A repeated-measures analysis of variance revealed no significant effect on peak lumbo-pelvic forces. However, the segmentation approach based on vertebral level resulted in significantly larger peak flexion and lateral flexion moments than the other BSP data sets. This has implications for comparisons between studies using different BSPs. Further, given that a method defined with reference to vertebral level more closely corresponds with relevant anatomical structures, this approach may more accurately reflect lumbar moments.

PMID: 23887979 [PubMed - in process]

Read more... http://www.ncbi.nlm.nih.gov/pubmed/23887979?dopt=Abstract

The influence of task frequency and force direction on psychophysically acceptable forces in the context of the biomechanically weakest links.

J Appl Biomech. 2013 Jun;29(3):285-91

Authors: Cudlip AC, Fischer SL, Wells R, Dickerson CR

Abstract
This study examined the influence of frequency and direction of force application on psychophysically acceptable forces for simulated work tasks. Fifteen male participants exerted psychophysically acceptable forces on a force transducer at 1, 3, or 5 repetitions per minute by performing both a downward press and a pull toward the body. These exertions were shown previously to be strength and balance limited, respectively. Workers chose acceptable forces at a lower percentage of their maximum voluntary force capacity during downward (strength-limited) exertions than during pulling (balance-limited) exertions at all frequencies (4% to 11%, P = .035). Frequency modulated acceptable hand force only during downward exertions, where forces at five repetitions per minute were 13% less (P = .005) than those at one exertion per minute. This study provides insight into the relationship between biomechanically limiting factors and the selection of acceptable forces for unilateral manual tasks.

PMID: 23887978 [PubMed - in process]

Read more... http://www.ncbi.nlm.nih.gov/pubmed/23887978?dopt=Abstract

Related Articles

Tibial subchondral bone mineral density: sources of variability and reproducibility.

Osteoarthritis Cartilage. 2013 Jul 22;

Authors: Boudenot A, Pallu S, Toumi H, Loiseau Peres S, Dolleans E, Lespessailles E

Abstract
OBJECTIVES: It has been shown that subchondral bone mineral density (sBMD) measurement may be a relevant parameter of osteoarthritis progression. However, factors implicating the reproducibility and contributing to the variability of the measurement have not been fully described. Thus, the aim of this study was to explore the reproducibility of sBMD by Dual energy X-ray Absorptiometry (DXA) and to further examine its sources of variability.
METHODS: In this study, short-term, intra and inter-observer reproducibility of sBMD was examined on knee images obtained on DXA scans. The influence of software (lumbar spine and forearm modes), knee positioning (flexion or extension), site and size of regions of interest (ROI) and use of rice, on both lateral and medial tibial sBMD, were assessed. Root mean square coefficient of variation (RMS CV) and least significant changes (LSC) were calculated.