A new method for the simulation of the mass distribution of cancellous bone is presented on the basis of finite element analysis (FEA). In this method,the process of bone remodelling is considered as a process of the topology optimization of a corresponding continuum structure. Fabric tensor is used to express the microstructure and the constitutive properties of cancellous bone. The effective volume fraction or the relative density of a point in the design domain is expressed by the invariables of the fabric tensor. A reference strain interval, which is corresponding to the strain dead zone of a bone in biomechanics, is applied to detect the the final topology of the structure. By the present approach, several numerical results are given, i. e., the simulation on the shape of the coronal plane of vertebrae, the predictions of the mass distributions of the two-dimensional and the three-dimensional proximal femurs. The validity and feasibility of this new method are verified by the comparison between the results of the present work and those in the published literatures.
Adaptation, Physiological ; Algorithms ; Biomechanical Phenomena ; Bone Density ; physiology ; Bone Remodeling ; physiology ; Bone and Bones ; physiology ; Computer Simulation ; Femur Head ; physiology ; Finite Element Analysis ; Humans ; Models, Biological ; Stress, Mechanical

In this paper, combined with the finite element (FE) method and optimization theory, a strain energy criterion is used to simulate and predict the bone remodeling. The strain energy density is taken as the mechanical stimulus. The bone remodeling is described as the changes of material distribution, which can represent the process of bone remodeling. By remodeling simulation of a two-dimensional proximal femur, a three-dimensional proximal femur and bone fracture healing plastic process, we demonstrate that this criterion can produce a realistic apparent density distribution in the proximal femur, and this criterion can well illuminate the mechanism of bone fracture healing plastic process.
Adaptation, Physiological ; physiology ; Biomechanical Phenomena ; Bone Remodeling ; physiology ; Bone and Bones ; physiology ; Computer Simulation ; Femur ; physiology ; Finite Element Analysis ; Humans ; Models, Biological ; Stress, Mechanical

At present, the numerical model of bone remodeling is inadequate to copy the physiological process of bone remodeling. According to the physiological mechanism of bone remodeling and the anisotropy of bone mechanics properties, an anisotropic bone modeling model with mechanostat was developed, and then was applied to a study on the remodeling evolution of 2D squareplate model. Good results were obtained. The model can be used in the study of implant, osteoporosis and other bone diseases.
Anisotropy ; Biomechanical Phenomena ; Bone Remodeling ; physiology ; Bone and Bones ; physiology ; Models, Biological ; Osteoporosis ; physiopathology

From the visual angle of mechanics, bone remodelling plays an important role in adapting to load environment and repairing microcracks. In order to describe the process of bone remodelling explicitly, we introduced a bone remodelling model representing the biological features of damage/repair in bone. Based on Basic Multicellular Units (BMUs), the model embodies not only the mechano-transduction of osteocytes' response to mechanical stimuli, but also the biological process of the randomly ocurring microcracks that are resorbed by osteoclasts and then refilled by osteoblasts. A 2-D trabecular bone finite element model was used as an initial configuration in the research. The developments in bone microstructure and material properties have been monitored in the course of 10 simulated years. The conclusions are: (1) Initially, trabecular bone changes prominently, but it tends to be stable later on; (2) The material properties of trabecular bone in compression are much better than in tension.
Biomechanical Phenomena ; Bone Remodeling ; physiology ; Bone and Bones ; injuries ; pathology ; physiology ; Humans ; Models, Biological ; Stress, Mechanical ; Wound Healing

Abstract The processs of female Osteoporosis and its prevention by Physical activity were simulated using anisotropic bone remodelling model with mechanostat combining with finite element method. The results show that bone mass declines slowly at the beginning, bone loss accelerates in postmenopause and bone mass declines 25. 84%-28.63% at the age of 60 and 38.50%-40.44% at the age of 80. Bone mass increases 3.05%-10.26% by an increase of 10%-20% in physical activity. The above results are consistent with clinical observations,which proves that declination of mechanical usage is the primary factor leading to osteoporosis, menopause quickens the process of female osteoporosis, physical activity can decelerate it.
Aged ; Biomechanical Phenomena ; Bone Remodeling ; Computer Simulation ; Exercise ; physiology ; Female ; Humans ; Middle Aged ; Models, Biological ; Osteoporosis, Postmenopausal ; prevention & control

Implant success is achieved by the synergistic combination of numerous biomechanical factors. This report examines the mechanical aspect of implants. In particular, it is focused on macrodesign such as thread shape, pitch, width and depth, and crestal module of implants. This study reviews the literature regarding the effect of implant thread geometry on primary stability and osseointegration under immediate loading. The search strategy included both in vitro and in vivo studies published in the MEDLINE database from January 2000 to June 2014. Various geometrical parameters are analyzed to evaluate their significance for optimal stress distribution, implant surface area, and bone remodeling responses during the process of osseointegration.
Bone Remodeling ; Dental Implants ; Osseointegration*

OBJECTIVETo discuss the primary stability of the fixed interface between the cementless prosthesis and femur, and its influence on bone ingrowth and secondary stability under the roughened surface and press fit of different prostheses by finite element analysis.

METHODS:A three-dimensional finite element module of total hip arthroplasty (THA) was developed with Mimics software. There was a collection of data when simulating hip arthroplasty. The frictional coefficient between the fixed interface was 0,0.15,0.40 and 1.00 representing the roughness of prosthesis surface. The press fit was 0, 0.01,0.05 and 0.10 mm according to the operation. The Vion Mises stress distribution and the contact pressure,friction stress and relative sliding displacement between the interface were analysed and compared when simulating the maneuver of climbing stairs.

RESULTSAt a fixed press fit of 0.05 mm,the contact pressure between the interface was 230 , 231, 222 and 275 MN under four different frictional coefficient (0,0. 15,0.40 and 1.00) with little change; the relative sliding displacement was 0.529, 0.129, 0.107 and 0.087 mm with a consistent and obvious decline. As the fixed frictional coefficient was 0.40,the contact pressure between the interface were 56.0,67.7 ,60.4 and 49.6 MN under four different press fit (0, 0.01, 0.05 and 0.10 mm) with a reduction; the relative sliding displacement was 0.064,0.062,0.043 and 0.042 mm with an obvious decline, and there was a maximal friction stress when press fit of 0.01 mm.

CONCLUSIONThere is a dynamic process of the bone remodeling and bone integration between the interface after hip replacement, determining the long-term outcome. The interface clearance and the frictional coefficient are the key factors of the bone integration.

Arthroplasty, Replacement, Hip ; Biomechanical Phenomena ; Bone Remodeling ; Bone and Bones ; chemistry ; physiopathology ; surgery ; Elasticity ; Finite Element Analysis ; Humans ; Models, Biological ; Stress, Mechanical

This paper presents an investigation on the effect of external force on internal bone remodeling by adopting the internal bone remodeling theory in conjunction with finite element method. After the border data are picked from a tomogram, a two-dimensional bone model is formed. The bone remodeling results are obtained by use of the finite element software Ansys. The results agree well with the real structure of bone in some degree, thus demonstrating the validity of the proposed method.
Biomechanical Phenomena ; Bone Density ; physiology ; Bone Remodeling ; physiology ; Finite Element Analysis ; Humans ; Models, Biological ; Stress, Mechanical ; Tibia ; diagnostic imaging ; physiology ; Tomography, X-Ray Computed

Presented is a method to set up a quantification model of bone growing and remodeling adaptation, which integrates animal experiments, parameter identification of mathematical functions and technique of computer simulation. By designing a new animal experiment, we investigate the effects of growing and remodeling of the rat femurs in different stress environments, gather the bone mineral density (BMD) of proximal femur in the same interval for the unknown parameter (B and K) inversion of bone growing and remodeling equation and create the femur three-dimensional geometrical model based on CT images. The model in this paper can not only numerically measure the relation between outer stimulus and the femur BMD variation of rapid growing rats, but also predict the growth trend of rat femur under different stress environments in its whole lifecycle. The thought and method of creating the model in this paper can be used for reference to modeling human bone growth and remodeling.
Adaptation, Physiological ; Animals ; Biomechanical Phenomena ; Bone Density ; Female ; Femur ; physiology ; Models, Biological ; Rats ; Rats, Sprague-Dawley ; Stress, Mechanical

Eight species belonging to two genera of the Laboulbeniales, parasitic on the family Carabidae and Staphylinidae of the order Coleoptera, were collected from Upo natural swamp in 1996-2001. They are as follows; Laboulbenia anoplogenii parasitic on Platynus daimio, L. cristata on Paederus parallelus, L. egens on Tachys laetifica, L. flagellata on Platynus daimio, L. pedicellata on Bembidion morawitzi, L. philonthi on Philonthus wuesthoffi, L. stenolophi on Acupalpus inornatus and Philonthus longicornis, and Peyritschiella biformis on Philonthus micaticollis. Among these species, the genus Platynus as the host of L. anoplogenii and the genus Acupalpus as the host of L. stenolophi are new to science. Bembidion morawitzi as the host of Laboulbenia pedicellata and Philonthus micanticollis as the host of Peyritschiella biformis are new to Korea.
Beetles ; Humans ; Korea ; Wetlands*