Comparison Between DEXA and Finite Element Studies in the Long-Term Bone Remodeling of an Anatomical Femoral Stem

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
A. Herrera ◽  
J. J. Panisello ◽  
E. Ibarz ◽  
J. Cegoñino ◽  
J. A. Puértolas ◽  
...  
Keyword(s):  
Finite Element ◽  
Bone Density ◽  
Bone Mass ◽  
Simulation Model ◽  
Load Transfer ◽  
Fe Simulation ◽  
Femoral Stem ◽  
Mineral Density ◽  
Biomechanical Behavior

The implantation of a cemented or cementless femoral stem changes the physiological load transfer on the femur producing an effect on the bone called adaptative remodeling. The patterns of this remodeling are attributed to mechanical and biological factors, and those changes in bone mineral density have been determined in long-term densitometry studies. This technique has proved to be a useful tool able to quantify small changes in bone density in different femoral areas, and it is considered to be ideal for long-term studies. On the other hand, the finite element (FE) simulation allows the study of the biomechanical changes produced in the femur after the implantation of a femoral stem. The aim of this study was to contrast the findings obtained from a 5 year follow-up densitometry study that used a newly designed femoral stem (73 patients were included in this study), with the results obtained using a finite element simulation that reproduces the pattern of load transfer that this stem causes on the femur. In this study we have obtained a good comparison between the results of stress of FE simulation and the bone mass values of the densitometry study establishing a ratio between the increases in stress (%) versus the increases in bone density (%). Hence, the changes in bone density in the long term, compared with the healthy femur, are due to different load transfers after stem implantation. It has been checked that in the Gruen zone 7 at 5 years, the most important reduction in stress (7.85%) is produced, which coincides with the highest loss of bone mass (23.89%). Furthermore, the simulation model can be used with different stems with several load conditions and at different time periods to carry out the study of biomechanical behavior in the interaction between the stem and the femur, explaining the evolution of bone density in accordance to Wolff’s law, which validates the simulation model.

Decreased Bone Density in Adolescent Girls With Anorexia Nervosa

PEDIATRICS ◽  
1990 ◽  
Vol 86 (3) ◽  
pp. 440-447 ◽  
Author(s):  
Laura K. Bachrach ◽  
David Guido ◽  
Debra Katzman ◽  
Iris F. Litt ◽  
Robert Marcus
Keyword(s):  
Bone Mineral Density ◽  
Body Mass Index ◽  
Anorexia Nervosa ◽  
Bone Density ◽  
Bone Mass ◽  
Body Mass ◽  
Bone Mineral ◽  
Whole Body ◽  
Mineral Density ◽  
Control Subjects

Osteoporosis develops in women with chronic anorexia nervosa. To determine whether bone mass is reduced in younger patients as well, bone density was studied in a group of adolescent patients with anorexia nervosa. With single- and dual-photon absorptiometry, a comparison was made of bone mineral density of midradius, lumbar spine, and whole body in 18 girls (12 to 20 years of age) with anorexia nervosa and 25 healthy control subjects of comparable age. Patients had significantly lower lumbar vertebral bone density than did control subjects (0.830 ± 0.140 vs 1.054 ± 0.139 g/cm2) and significantly lower whole body bone mass (0.700 ± 0.130 vs 0.955 ± 0.130 g/cm2). Midradius bone density was not significantly reduced. Of 18 patients, 12 had bone density greater than 2 standard deviations less than normal values for age. The diagnosis of anorexia nervosa had been made less than 1 year earlier for half of these girls. Body mass index correlated significantly with bone mass in girls who were not anorexic (P < .05, .005, and .0001 for lumbar, radius, and whole body, respectively). Bone mineral correlated significantly with body mass index in patients with anorexia nervosa as well. In addition, age at onset and duration of anorexia nervosa, but not calcium intake, activity level, or duration of amenorrhea correlated significantly with bone mineral density. It was concluded that important deficits of bone mass occur as a frequent and often early complication of anorexia nervosa in adolescence. Whole body is considerably more sensitive than midradius bone density as a measure of cortical bone loss in this illness. Low body mass index is an important predictor of this reduction in bone mass.

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 < 0.0001 for both), cortical thickness (radius: +1.1 ± 2%, tibia: +2.0 ± 3%; P < 0.01 for both), and trabecular bone volume (radius: +3.8 ± 5%, tibia: +3.2 ± 4%; P < 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 < 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 The influence of sports on indicators of mineral bone density among women descendants of migrants of KHMAO-Yugra

2016 ◽  
Vol 12 (1) ◽  
pp. 198-200
Author(s):  
Maxim V Stogov ◽  
Natalya V Chernitsyna ◽  
Roman V Kuchin
Keyword(s):  
Bone Density ◽  
Bone Mass ◽  
Bone Tissue ◽  
Preliminary Data ◽  
First Generation ◽  
Physical Culture ◽  
Mineral Density ◽  
Autonomous District ◽  
Middle Latitudes ◽  
Mineral Bone Density

The study shows that women descendants of migrants in the first generation, born and residing on the territory of KHMAO-Yugra, not engaged in physical culture and sports, according to densitometry mineral density of bone tissue shows signs of loss of bone mass, not observed in the residents of middle latitudes and the girls engaged in physical culture and sports, living in the Khanty-Mansiysk Autonomous district-Yugra. Preliminary data confirm the assumption that training in physical culture and sport contribute to the prevention of loss of bone mass in women living in the territory of KHMAO-Yugra.

Bone Density and Mineral Metabolism in Thyroidectomized Patients Treated with Long-Term l-Thyroxine

1994 ◽  
Vol 87 (5) ◽  
pp. 593-597 ◽  
Author(s):  
Sandro Giannini ◽  
Martino Nobile ◽  
Leonardo Sartori ◽  
Pierluigi Binotto ◽  
Matteo Ciuffreda ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
Bone Density ◽  
Bone Mass ◽  
Mineral Metabolism ◽  
Menopausal Status ◽  
Bone Alkaline Phosphatase ◽  
Thyroid Stimulating Hormone ◽  
Control Subjects ◽  
And Control

1. A decreased bone mass has been reported in patients with endogenous hyperthyroidism, but the effect on bone density and mineral metabolism of thyroxine administration in thyroidectomized patients is still controversial. To further contribute to this debate, we studied 25 women thyroidectomized for thyroid cancer on long-term treatment with thyroid-stimulating hormone-suppressive doses of L-thyroxine. Twenty-one sex- and age-matched normal subjects were also studied as a control group. 2. The bone density of the spine and serum calcitonin, calcitriol and parathyroid hormone concentrations were not different when the whole patient group was compared with the control subjects, nor when the patients and control subjects were compared according to their menopausal status. However, postmenopausal thyroidectomized patients showed significantly lower bone mass (P < 0.001) than premenopausal patients. 3. L-Thyroxine-treated patients showed significantly higher levels of bone alkaline phosphatase and urine hydroxyproline excretion than control subjects (P < 0.003 and P < 0.001, respectively). These differences were still present when patients and control subjects were analysed according to their menopausal status. However, bone alkaline phosphatase was significantly higher in postmenopausal than in premenopausal women only in L-thyroxine-treated patients (P < 0.05). In postmenopausal L-thyroxine-treated patients a negative correlation between time since menopause and bone mass (P < 0.05) and a positive correlation between bone alkaline phosphatase and hydroxyproline excretion (P < 0.03) were also found. 4. We conclude that long-term thyroid-stimulating hormone-suppressive treatment with L-thyroxine in thyroidectomized women is not associated with a decrease in spinal bone mass nor with calcitonin deficiency, and that L-thyroxine treatment may increase skeletal sensitivity to menopause-related bone loss.

Effect of denosumab on bone density and turnover in postmenopausal women with low bone mass after long-term continued, discontinued, and restarting of therapy: A randomized blinded phase 2 clinical trial

Bone ◽  
2008 ◽  
Vol 43 (2) ◽  
pp. 222-229 ◽  
Author(s):  
Paul D. Miller ◽  
Michael A. Bolognese ◽  
E. Michael Lewiecki ◽  
Michael R. McClung ◽  
Beiying Ding ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Bone Density ◽  
Bone Mass ◽  
Postmenopausal Women ◽  
Phase 2 ◽  
Low Bone Mass ◽  
Phase 2 Clinical Trial

Finite Element Evaluation of Biomechanical Changes of Lumbar Segment Implanted With an Anterior Disc After Subsidance

2008 ◽  
Author(s):  
A. Kiapour ◽  
V. K. Goel ◽  
C. K. Lee ◽  
J. N. Grauer ◽  
H. Serhan
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Lumbar Disc ◽  
Load Sharing ◽  
Artificial Disc ◽  
Biomechanical Behavior ◽  
Lumbar Segment ◽  
Biomechanical Changes ◽  
Vertebral Endplates

Biomechanical studies of artificial discs that quantify parameters like kinematics, the load sharing and stresses have been reported in literature for various artificial disc designs; however literature on the long term biomechanical behavior of the implant in the spine is sparse. Disc subsidence is one of the potential long term issues. In this study finite element method was used to investigate the biomechanics of Charite anterior lumbar disc (DePuy Spine, MA) following potential subsidence of the implant into vertebral endplates.

Decreased bone mass and increased bone turnover with valproate therapy in adults with epilepsy [RETRACTED]

Neurology ◽  
2001 ◽  
Vol 57 (3) ◽  
pp. 445-449 ◽  
Author(s):  
Y. Sato ◽  
I. Kondo ◽  
S. Ishida ◽  
H. Motooka ◽  
K. Takayama ◽  
...  
Keyword(s):  
Bone Resorption ◽  
Bone Mass ◽  
Calcium Metabolism ◽  
Type I Collagen ◽  
Bone Resorption Marker ◽  
Type I ◽  
Serum Concentrations ◽  
Mineral Density ◽  
Z Scores

Background: Bone loss and hypovitaminosis D are reported in patients taking antiepileptic drugs, but little is known about changes in bone and calcium metabolism from valproic acid (VPA).Objective: To assess the relationship of VPA to bone mass and calcium metabolism in 40 adults with epilepsy on long-term VPA monotherapy, 40 age- and sex-matched epileptic patients taking phenytoin (PHT), and 40 healthy control subjects. Bone mineral density (BMD) of the second metacarpal was determined as T- and Z-scores.Results: BMD reduction from control values was 14% (12% in men, 16% in women) with VPA and 13% (12% in men, 15% in women) with PHT. Among patients on VPA, nine (23%) had T-scores below −2.5 SD, suggesting osteoporosis; 15 (37%) had T-scores between −1 and −2.5 SD, suggesting osteopenia. Serum concentrations of calcium were significantly higher with VPA than in PHT or control groups. Serum concentrations of bone Gla protein (a bone formation marker) and pyridinoline cross-linked carboxy-terminal telopeptide of type I collagen (ICTP; a bone resorption marker) associated with either drug significantly exceeded control values. Z-scores for BMD in the VPA group correlated negatively with calcium and ICTP. High ICTP correlated positively with ionized calcium, implying that increased bone resorption caused the latter.Conclusion: Long-term VPA monotherapy can increase bone resorption, leading to decreased BMD.

scholarly journals Pengaruh Latihan Resisten terhadap Kepadatan Tulang

2021 ◽  
Vol 9 (2) ◽  
Author(s):  
Audy K. Bella ◽  
Hedison Polii ◽  
Herlina I. S. Wungow
Keyword(s):  
Resistance Training ◽  
Bone Density ◽  
Literature Review ◽  
Bone Mass ◽  
Resistance Exercise ◽  
Mass Density ◽  
Anaerobic Exercise ◽  
Google Scholar ◽  
Bone Mass Density ◽  
Mineral Density

Abstract : Resistance or resistance training has been recommended as a widely used treatment strategy for dealing with bone loss. Types of exercise that can be done include walking, running, weights bearing, and swimming. According to WHO in 2018, more than 80% of the adult population worldwide has less physical activity. Studies show that resistant exercise can increase bone density. This literature review aims to determine the effect of resistance training on bone density. This study was in the form of a literature review with data searches using four databases, which are ClinicalKey, Pubmed, MedLine, and Google Scholar. Resistance exercise can increase bone density. There are two types of exercise, named aerobic and anaerobic exercises. Research has shown that anaerobic exercise is more effective in increasing bone mass density compared to aerobic exercise because anaerobic exercise provides a bigger mechanical load to the bones, which triggers the bones to regenerate. The conclusion is that resistance exercise can increase bone density.Keywords : Resistance exercise, bone density.  Abstrak : Latihan tahanan atau resisten telah direkomendasikan sebagai strategi pengobatan yang banyak digunakan untuk menghadapi hilangnya massa tulang. Jenis latihan yang bisa dilakukan antara lain jalan kaki, berlari, angkat beban, dan berenang. Menurut WHO pada tahun 2018, lebih dari 80% populasi orang dewasa di seluruh dunia memiliki aktivitas fisik yang kurang. Penelitian-penelitian membuktikan bahwa latihan resisten dapat meningkatkan kepadatan tulang. Tinjauan pustaka ini bertujuan untuk mengetahui pengaruh latihan resisten terhadap kepadatan tulang. Penelitian ini berbentuk literature review dengan pencarian data menggunakan empat database yaitu ClinicalKey, Pubmed, MedLine, dan Google Scholar. Kata kunci yang digunakan yaitu physical exercise ATAU resistance exercise ATAU resistance training ATAU effect of resistance exercise ATAU latihan tahanan ATAU latihan beban DAN bone mass ATAU bone mineral density. Latihan secara resisten dapat meningkatkan kepadatan tulang. Latihan dapat dilakukan dengan dua jenis, yaitu latihan aerobik dan anaerobik. Penelitian membuktikan bahwa latihan anaerobik lebih efektif dalam menungkatkan kepadatan massa tulang dibandingkan dengan latihan aerobik karena latihan anaerobik memberikan beban mekanik yang lebih besar untuk tulang sehingga memicu tulang untuk melakukan regenerasi.  Kesimpulannya adalah latihan resisten dapat meningkatkan kepadatan tulang.Kata Kunci : Latihan resisten, kepadatan tulang

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