Stresses in the Growth Plate of the Developing Proximal Femur

2001 ◽  
Vol 17 (2) ◽  
pp. 129-141 ◽  
Author(s):  
Thomas G. Ribble ◽  
Michael H. Santare ◽  
Freeman Miller
Keyword(s):  
Finite Element ◽  
Growth Plate ◽  
Proximal Femur ◽  
Normal Development ◽  
Normal Activity ◽  
Shear Stresses ◽  
Finite Element Models ◽  
Loading Conditions ◽  
Neck Shaft Angle ◽  
Shaft Angle

Finite element models of the proximal femur at birth, 2 years of age, and at 8 years of age were constructed to investigate stress patterns under different loading conditions. These loading conditions represent typical activities of a normal developing child and abnormal activity associated with muscle spasticity. The hypothesis is that the shear stresses in the growth plate correlate with the neckshaft angle as associated with valgus and normal development. Loads for the finite element models were derived from a separate muscle model used to calculate the forces across the hip joint for an arbitrary subject and activity. Results show there is an inverse relationship between the relative magnitude of the shear stress in the growth plate and the developing neck-shaft angle. The relatively high shear stresses generated by normal activity in the 2-year-old’s growth plate correlate with the decrease in neck-shaft angle that accompanies normal development. Alternatively, lower shear stresses are generated in the growth plate by loading conditions representing spasticity. These lower magnitude shear stresses correlate with a valgus deformity, which is often observed clinically.

scholarly journals The effects of femoral metaphyseal morphology on growth plate biomechanics in juvenile chimpanzees and humans

2021 ◽  
Vol 11 (5) ◽  
pp. 20200092
Author(s):  
Peter A. Stamos ◽  
Michael A. Berthaume
Keyword(s):  
Finite Element ◽  
Surface Morphology ◽  
Growth Plate ◽  
Finite Element Models ◽  
Loading Conditions ◽  
Locomotor Behaviour ◽  
Knee Loading ◽  
Subject Specific ◽  
Von Mises ◽  
Von Mises Stresses

The distal femoral metaphyseal surface presents dramatically different morphologies in juvenile extant hominoids—humans have relatively flat metaphyseal surfaces when compared with the more complex metaphyseal surfaces of apes. It has long been speculated that these different morphologies reflect different biomechanical demands placed on the growth plate during locomotor behaviour, with the more complex metaphyseal surfaces of apes acting to protect the growth plate during flexed-knee behaviours like squatting and climbing. To test this hypothesis, we built subject-specific parametric finite-element models from the surface scans of the femora of five Pan and six Homo juveniles. We then simulated the loading conditions of either a straight-leg or flexed-knee gait and measured the resulting stresses at the growth plate. When subjected to the simulated flexed-knee loading conditions, both the maximum and mean von Mises stresses were significantly lower in the Pan models than in the Homo models. Further, during these loading conditions, von Mises stresses were strongly negatively correlated with ariaDNE, a measure of complexity of the metaphyseal surface. These results indicate that metaphyseal surface morphology has a robust effect on growth plate mechanics.

Effect of Combined Shear Stresses on the Ultimate Axial Response of the Double Bottom of a Containership

2016 ◽  
Author(s):  
Marco Gaiotti ◽  
Riccardo Bacoccoli ◽  
Masahiko Fujikubo ◽  
Cesare Mario Rizzo
Keyword(s):  
Finite Element ◽  
Ultimate Strength ◽  
International Association ◽  
Shear Stresses ◽  
Finite Element Models ◽  
Loading Conditions ◽  
Significant Issue ◽  
Hull Girder ◽  
Longitudinal Strength ◽  
Axial Response

Ultimate strength of the hull girder of containerships became a significant issue in the last years in view of recent accidents and related investigations. Actually, larger and larger ships were put into service and still are designed and built. Recognizing such an issue, investigations were carried out and led to the issuance of a specific longitudinal strength standard for containerships by the International Association of Classification Societies [1]. Loading conditions become more and more challenging and especially combinations of various actions were found to impair the hull girder ultimate strength. In the attempt to better understand the influence of load combinations onto the ultimate strength of the hull girder, investigations were carried out. In this paper, the effects of the shear is considered using rather refined and accurate finite element models of a typical containership double bottom.

Fracture Prediction for the Proximal Femur Using Finite Element Models: Part I—Linear Analysis

1991 ◽  
Vol 113 (4) ◽  
pp. 353-360 ◽  
Author(s):  
J. C. Lotz ◽  
E. J. Cheal ◽  
W. C. Hayes
Keyword(s):  
Finite Element ◽  
Fracture Risk ◽  
Strain Gage ◽  
Proximal Femur ◽  
Material Properties ◽  
The United States ◽  
Nonlinear Material ◽  
Finite Element Models ◽  
Model Predictions

Over 90 percent of the more than 250,000 hip fractures that occur annually in the United States are the result of falls from standing height. Despite this, the stresses associated with femoral fracture from a fall have not been investigated previously. Our objectives were to use three-dimensional finite element models of the proximal femur (with geometries and material properties based directly on quantitative computed tomography) to compare predicted stress distributions for one-legged stance and for a fall to the lateral greater trochanter. We also wished to test the correspondence between model predictions and in vitro strain gage data and failure loads for cadaveric femora subjected to these loading conditions. An additional goal was to use the model predictions to compare the sensitivity of several imaging sites in the proximal femur which are used for the in vivo prediction of hip fracture risk. In this first of two parts, linear finite element models of two unpaired human cadaveric femora were generated. In Part II, the models were extended to include nonlinear material properties for the cortical and trabecular bone. While there was poor correspondence between strain gage data and model predictions, there was excellent agreement between the in vitro failure data and the linear model, especially using a von Mises effective strain failure criterion. Both the onset of structural yielding (within 22 and 4 percent) and the load at fracture (within 8 and 5 percent) were predicted accurately for the two femora tested. For the simulation of one-legged stance, the peak stresses occurred in the primary compressive trabeculae of the subcapital region. However, for a simulated fall, the peak stresses were in the intertrochanteric region. The Ward’s triangle (basicervical) site commonly used for the clinical assessment of osteoporosis was not heavily loaded in either situation. These findings suggest that the intertrochanteric region may be the most sensitive site for the assessment of fracture risk due to a fall and the subcapital region for fracture risk due to repetitive activities such as walking.

Development of Simplified Spot Weld Models: Stiffness Prediction and Computational Performance Evaluation

2010 ◽  
Author(s):  
Noman Khandoker ◽  
Monir Takla ◽  
Thomas Ting
Keyword(s):  
Finite Element ◽  
Spot Weld ◽  
Finite Element Models ◽  
Suitable Model ◽  
Loading Conditions ◽  
Computational Costs ◽  
Automotive Body ◽  
Simple Strategy ◽  
Pull Out ◽  
Computational Performance

Simple spot weld connection models are desirable in huge and complicated finite element models of automotive body-in-white structures which generally contains thousands of spot weld joints. Hence, in this paper six different individual spot weld joint finite element models simplified in terms of their geometric and constitutive representations were developed including the one that is currently used in automotive industries. The stiffness characteristics of these developed models were compared with the experimental results obtained following a simple strategy to design the welded joint based on the desired mode of nugget pull out failure. It was found that the current spot weld modeling practice in automotive industry under predict the maximum joint strength nearly by 50% for different loading conditions. The computational costs incurred by the developed models in different loading conditions were also compared. Hence, a suitable model for spot welded joints is established which is very simple to develop but relatively cheap in terms of computational costs.

scholarly journals A MORPHOMETRIC STUDY OF THE PROXIMAL END OF DRY ADULT FEMORA

2020 ◽  
Vol 8 (4.2) ◽  
pp. 7799-7804
Author(s):  
Ishita Sengupta ◽  
◽  
Madhumita Mahato ◽  
Gairik Sengupta ◽  
Jadab Chandra Chattopadhyay ◽  
...  
Keyword(s):  
Proximal Femur ◽  
Indian Population ◽  
Traumatic Injury ◽  
Morphometric Study ◽  
Neck Of Femur ◽  
Posterior Aspect ◽  
Neck Shaft Angle ◽  
East Indian ◽  
Fracture Neck Femur ◽  
Shaft Angle

Background: A good understanding of morphometric measurements of the proximal femur is essential in order to decrease the risk of complications associated with orthopedic surgeries performed in the proximal femur due to traumatic injury, metabolic or vascular causes, and to achieve proper alignment of prosthesis to be implanted. The purpose of this study is to evaluate morphometry of neck of femur in Eastern Indian population. Materials and Methods: The study was conducted on 50 dry adult femora [30 Right(R) and 20 Left(L)] available in the department of Anatomy of Medical College Kolkata, India. Results: a) Mean and Standard Deviation (SD) of Vertical length of Head of femur was Right side: 38.56±2.50mm and Left side: 38.07±3.43mm. b) Mean and SD of Width of neck of femur was Right side: 28.84±2.71mm and Left side:28.09±2.29mm. c) Mean and SD of length of Neck of femur on anterior aspect was Right side:26.37±2.92mm and Left side:26.12±3.42mm. d) Mean and SD of length of Neck of femur on posterior aspect was Right side:31.65±2.75mm and Left side:26.69±3.11mm. e) Neck-shaft angle on both sides were calculated. Conclusion: Indian dimensions of proximal end of femur are different as compared to that of the values in other parts of the world. Present study will be useful for crafting suitable implants used for surgical correction of fracture neck femur in East Indian population. KEYWORDS: Morphometry, Neck-shaft angle, Implant, Prosthesis, Width of neck, Vertical length of head of femur, Length of neck.

scholarly journals Three-dimensional morphological study of the proximal femur in Crowe type IV developmental dysplasia of the hip

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Yuhui Yang ◽  
Weihong Liao ◽  
Weiqun Yi ◽  
Hai Jiang ◽  
Guangtao Fu ◽  
...  
Keyword(s):  
Femoral Neck ◽  
Proximal Femur ◽  
Three Dimensional ◽  
Developmental Dysplasia ◽  
Medullary Canal ◽  
Femoral Offset ◽  
Neck Shaft Angle ◽  
Type Iv ◽  
Shaft Angle ◽  
Dysplasia Of The Hip

Abstract Background When performing femoral reconstruction in patients with Crowe type IV developmental dysplasia of the hip (DDH), anatomical deformity presents many technical challenges to orthopedic surgeons. The false acetabulum is suggested to influence load transmission and femoral development. The aim of this study was to describe the morphological features of dysplastic femurs in Crowe type IV DDH and further evaluate the potential effect of the false acetabulum on morphological features and medullary canal of Crowe type IV femurs. Methods We analyzed preoperative computed tomography scans from 45 patients with 51 hips (25 hips without false acetabulum in the IVa group and 26 hips with false acetabulum in the IVb group) who were diagnosed with Crowe type IV DDH and 30 normal hips in our hospital between January 2009 and January 2019. Three-dimensional reconstruction was performed using Mimics software, and the coronal femoral plane was determined to evaluate the following parameters: dislocation height, dislocation ratio, height of the femoral head (FH), height of the greater trochanter (GT), GT–FH height discrepancy, height of the isthmus, neck-shaft angle, femoral offset and anteversion of the femoral neck. The mediolateral (ML) width, anterolateral (AP) width and diameter of medullary canal of the proximal femur were measured on the axial sections. Further, canal flare index (CFI), metaphyseal-CFI and diaphyseal-CFI were also calculated. Results Compared with the normal femurs, the Crowe type IV DDH femurs had a higher femoral head, larger GT–FH height discrepancy, larger femoral neck anteversion, higher isthmus position and smaller femoral offset. Dislocation height and dislocation rate were significantly larger in the IVa DDH group (65.34 ± 9.83 mm vs. 52.24 ± 11.42 mm). Further, the IVb femurs had a significantly lower isthmus position, larger neck-shaft angle and smaller femoral neck anteversion than IVa femurs. The ML, AP canal widths and the diameter of medullary canal in both DDH groups were significantly smaller than the normal group. Dimensional parameters of IVa femurs were also narrower than IVb femurs in most sections, but with no difference at the level of isthmus. According to the CFIs, the variation of proximal medullary canal in IVb femurs was mainly located in the diaphyseal region, while that in IVa femurs was located in the whole proximal femur. Conclusions High dislocated femurs are associated with more anteverted femoral neck, smaller femoral offset and narrower medullary canal. Without stimulation of the false acetabulum, IVa DDH femurs were associated with higher dislocation and notably narrower medullary canal, whose variation of medullary canal was located in the whole proximal femur.

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