Can neck fractures in proximal humeri be predicted by CT-based FEA?

Background: Proximal humeri fractures at anatomical and surgical neck (∼5% and ∼50% incidence respectively) are frequent in elderly population. Yet, neither in-vitro experiments nor CT-based finite element analyses (CTFEA) have investigated these in depth. Herein we enhance (Dahan et al.

Attachment and task persistence: attachment orientations, perception of teacher's responsiveness, and adolescents' persistence in academic tasks.

The goal of the two studies reported here was to examine the contribution of adolescents' attachment orientations (anxiety, avoidance) and their perception of teacher's responsiveness to persistence in academic tasks. In Study 1 ( = 160), we assessed self-reports of persistence in schoolwork. In Study 2 ( = 240), we manipulated the symbolic presence of participants' teacher () and assessed their actual persistence in a cognitive task.

Finite element analyses for predicting anatomical neck fractures in the proximal humerus.

Background: Proximal humerus fractures which occur as a result of a fall on an outstretched arm are frequent among the elderly population. The necessity of stabilizing such fractures by surgical procedures is a controversial matter among surgeons. Validating a personalized FE analysis by ex-vivo experiments of humeri and mimicking such fractures by experiments is the first step along the path to determine the necessity of such surgeries.

A novel phase field method for modeling the fracture of long bones.

A proximal humerus fracture is an injury to the shoulder joint that necessitates medical attention. While it is one of the most common fracture injuries impacting the elder community and those who suffer from traumatic falls or forceful collisions, there are almost no validated computational methods that can accurately model these fractures. This could be due to the complex, inhomogeneous bone microstructure, complex geometries, and the limitations of current fracture mechanics methods.

Scanner influence on the mechanical response of QCT-based finite element analysis of long bones.

Patient-specific QCT-based finite element (QCTFE) analyses enable highly accurate quantification of bone strength. We evaluated CT scanner influence on QCTFE models of long bones. A femur, humerus, and proximal femur without the head were scanned with KHPO phantoms by seven CT scanners (four models) using typical clinical protocols.

Verified and validated finite element analyses of humeri.

Background: Although ~200,000 emergency room visits per year in the US alone are associated with fractures of the proximal humerus, only limited studies exist on their mechanical response. We hypothesise that for the proximal humeri (a) the mechanical response can be well predicted by using inhomogeneous isotropic material properties, (b) the relation between bone elastic modulus and ash density (E(ρash)) is similar for the humerus and the femur, and may be general for long bones, and (c) it is possible to replicate a proximal humerus fracture in vitro by applying uniaxial compression on humerus׳ head at a prescribed angle.

Methods: Four fresh frozen proximal humeri were CT-scanned, instrumented by strain-gauges and loaded at three inclination angles.

Predicting the stiffness and strength of human femurs with real metastatic tumors.

Background: Predicting patient specific risk of fracture in femurs with metastatic tumors and the need for surgical intervention are of major clinical importance. Recent patient-specific high-order finite element methods (p-FEMs) based on CT-scans demonstrated accurate results for healthy femurs, so that their application to metastatic affected femurs is considered herein.

Methods: Radiographs of fresh frozen proximal femur specimens from donors that died of cancer were examined, and seven pairs with metastatic tumor were identified.