Comparison of Mechanical Stress and Change in Bone Mineral Density Between Two Types of Femoral Implant Using Finite Element Analysis

2013 ◽  
Vol 28 (10) ◽  
pp. 1731-1735 ◽  
Author(s):  
Yasuhide Hirata ◽  
Yutaka Inaba ◽  
Naomi Kobayashi ◽  
Hiroyuki Ike ◽  
Hiroshi Fujimaki ◽  
...  
Keyword(s):  
Bone Mineral Density ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Mechanical Stress ◽  
Bone Mineral ◽  
Mineral Density ◽  
Element Analysis

scholarly journals Elastic Modulus of Osteoporotic Mouse Femur Based on Femoral Head Compression Test

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Chang-soo Chon ◽  
Hui-suk Yun ◽  
Han Sung Kim ◽  
Cheolwoong Ko
Keyword(s):  
Bone Mineral Density ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Elastic Modulus ◽  
Femoral Head ◽  
Bone Mineral ◽  
Compression Test ◽  
Bending Test ◽  
Mineral Density ◽  
Element Analysis

A biomechanical test is a good evaluation method that describes the structural, functional, and pathological differences in the bones, such as osteoporosis and fracture. The tensile test, compression test, and bending test are generally performed to evaluate the elastic modulus of the bone using mice. In particular, the femoral head compression test is mainly used for verifying the osteoporosis change of the femoral neck. This study conducted bone mineral density analysis using in vivo microcomputed tomography (micro-CT) to observe changes in osteoporosis over time. It proposed a method of identifying the elastic modulus of the femur in the normal group (CON group) and the osteoporotic group (OVX group) through finite element analysis based on the femoral head compression test and also conducted a comparative analysis of the results. Through the femoral head compression test, it was verified that the CON group’s ultimate and yield loads were significantly higher than those of the OVX group. It was considered that this result was caused by the fact that the bone mineral density change by osteoporosis occurred in the proximal end more often than in the femur diaphysis. However, the elastic modulus derived from the finite element analysis showed no significant difference between the two groups.

scholarly journals Patient-Specific Phantomless Estimation of Bone Mineral Density and Its Effects on Finite Element Analysis Results: A Feasibility Study

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Young Han Lee ◽  
Jung Jin Kim ◽  
In Gwun Jang
Keyword(s):  
Bone Mineral Density ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Lumbar Spine ◽  
Regression Model ◽  
Proximal Femur ◽  
Strain Energy ◽  
Mineral Density ◽  
Element Analysis ◽  
Reference Phantom

Objectives. This study proposes a regression model for the phantomless Hounsfield units (HU) to bone mineral density (BMD) conversion including patient physical factors and analyzes the accuracy of the estimated BMD values. Methods. The HU values, BMDs, circumferences of the body, and cross-sectional areas of bone were measured from 39 quantitative computed tomography images of L2 vertebrae and hips. Then, the phantomless HU-to-BMD conversion was derived using a multiple linear regression model. For the statistical analysis, the correlation between the estimated BMD values and the reference BMD values was evaluated using Pearson’s correlation test. Voxelwise BMD and finite element analysis (FEA) results were analyzed in terms of root-mean-square error (RMSE) and strain energy density, respectively. Results. The HU values and circumferences were statistically significant (p<0.05) for the lumbar spine, whereas only the HU values were statistically significant (p<0.05) for the proximal femur. The BMD values estimated using the proposed HU-to-BMD conversion were significantly correlated with those measured using the reference phantom: Pearson’s correlation coefficients of 0.998 and 0.984 for the lumbar spine and proximal femur, respectively. The RMSEs of the estimated BMD values for the lumbar spine and hip were 4.26 ± 0.60 (mg/cc) and 8.35 ± 0.57 (mg/cc), respectively. The errors of total strain energy were 1.06% and 0.91%, respectively. Conclusions. The proposed phantomless HU-to-BMD conversion demonstrates the potential of precisely estimating BMD values from CT images without the reference phantom and being utilized as a viable tool for FEA-based quantitative assessment using routine CT images.

scholarly journals Skeletal Microstructure and Estimated Bone Strength Improve Following Parathyroidectomy in Primary Hyperparathyroidism

2017 ◽  
Vol 103 (1) ◽  
pp. 196-205 ◽  
Author(s):  
Natalie E Cusano ◽  
Mishaela R Rubin ◽  
Barbara C Silva ◽  
Yu-Kwang Donovan Tay ◽  
John M Williams ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Bone Density ◽  
Primary Hyperparathyroidism ◽  
Fracture Risk ◽  
Bone Strength ◽  
Failure Load ◽  
Mineral Density ◽  
Element Analysis ◽  
Volumetric Bone Density

Abstract Context High-resolution peripheral quantitative computed tomography (HRpQCT) is a noninvasive imaging technology that can provide insight into skeletal microstructure and strength. In asymptomatic primary hyperparathyroidism (PHPT), HRpQCT imaging has demonstrated both decreased cortical and trabecular indices, consistent with evidence for increased fracture risk. There are limited data regarding changes in HRpQCT parameters postparathyroidectomy. Objective To evaluate changes in skeletal microstructure by HRpQCT in subjects with PHPT after parathyroidectomy. Design We studied 29 subjects with PHPT (21 women, 8 men) with HRpQCT at baseline and 6, 12, 18, and 24 months postparathyroidectomy. Main Outcome Measures Volumetric bone mineral density, microarchitectural indices, and finite element analysis at the distal radius and tibia. Results At both the radius and tibia, there were significant improvements in total, cortical, and trabecular volumetric bone density as early as 6 months postparathyroidectomy (24-month values for total volumetric bone density, radius: +2.8 ± 4%, tibia: +4.4 ± 4%; P &lt; 0.0001 for both), cortical thickness (radius: +1.1 ± 2%, tibia: +2.0 ± 3%; P &lt; 0.01 for both), and trabecular bone volume (radius: +3.8 ± 5%, tibia: +3.2 ± 4%; P &lt; 0.0001 for both). At both sites, by finite element analysis, stiffness and failure load were improved starting at 6 months postparathyroidectomy (24-month values for failure load, radius: +6.2 ± 6%, tibia: +4.8 ± 7%; P &lt; 0.0001 for both). Conclusions These results provide information about skeletal microarchitecture in subjects with PHPT followed through 2 years after parathyroidectomy. Estimated bone strength is improved, consistent with data showing decreased fracture risk postparathyroidectomy.

scholarly journals Biomechanical Analysis of Various Reconstructive Methods for the Mandibular Body and Ramus Defect Using a Free Vascularized Fibula Flap

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Xian Li ◽  
Chao Jiang ◽  
Hui Gao ◽  
Chunjuan Wang ◽  
Chao Wang ◽  
...  
Keyword(s):  
Bone Mineral Density ◽  
Finite Element ◽  
Bone Mineral ◽  
Mineral Density ◽  
Fibula Flap ◽  
Surgical Methods ◽  
Vascularized Fibula ◽  
Mandibular Body ◽  
Reconstructive Methods

Several different methods exist for reconstructing the mandibular body and ramus defect with the use of a free vascularized fibula flap, but none have adequately addressed the long-term mechanical stability and osseointegration. The aim of this study is to compare the biomechanics of different surgical methods and to investigate the best approach for reconstructing the mandibular body and ramus defect. Five finite element models based on different reconstructive methods were simulated. Stress, strain, and displacement of connective bone sections were calculated for five models and compared. The models were printed using a 3D printer, and stiffness was measured using an electromechanical universal testing machine. The postoperative follow-up cone beam computed tomography (CBCT) was taken at different time points to analyze bone mineral density of connective bone sections. The results showed that the “double up” (DU) model was the most efficient for reconstructing a mandibular body and ramus defect by comparing the mechanical distribution of three sections under vertical and inclined loading conditions of 100 N. The stiffness detection showed that stiffness in the DU and “double down” (DD) models was higher compared with the “single up” (SU), “single down” (SD), and “distraction osteogenesis” (DO) models. We used the DU model for the surgery, and postoperative follow-up CBCT showed that bone mineral density of each fibular connective section increased gradually with time, plateauing at 12 weeks. We conclude that a free vascularized fibula flap of the DU type was the best approach for the reconstruction of the mandibular body and ramus defect. Preoperative finite element analysis and stiffness testing were shown to be very useful for maxillofacial reconstruction.

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