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Objective To investigate the structure and biomechanical property differences in different regions of the femoral head for elderly patients with femoral neck fractures,and to study its influence on internal fixation for fracture.Methods Twenty femoral head specimens were collected from elderly patients with femoral neck fracture after joint replacement.The femoral head was divided into 3 parts (lateral,inferior and medial region) with reference to anatomical markers on surface of the femoral head.After the position and drilling direction of the ring drill were determined,a circular drill was used to obtain the cylindrical cancellous bone columns with 10 mm in diameter and 10 mm in height.The data of cancellous bone columns in different regions were analyzed by Micro-CT scanning system,including bone volume fraction (BVF),trabecular space (Tb.Sp),trabecular thickness (Tb.Th),the number of trabecular number (Tb.N),the bone surface volume ratio (bone surface/bone volume,BS/BV),structural model index (SMI).Mechanical property differences of bone tissues in different regions were calculated by micro-finite element analysis.Results Bone mass in the elderly osteoporotic femoral head decreased,and there were significant differences in bone microstructure and mechanical properties in different regions of the femoral head.Bone microstructure and mechanical properties in medial region were obviously superior to those in lateral and interior region.Conclusions The bone structure and mechanical strength in medial region of the femoral head are obvious superior to those in lateral and inferior regions.The position for internal fixation should be fully considered during treatment of osteoporotic femoral neck fracture in clinic.
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Objective To investigate the structure and biomechanical property differences in different regions of the femoral head for elderly patients with femoral neck fractures,and to study its influence on internal fixation for fracture.Methods Twenty femoral head specimens were collected from elderly patients with femoral neck fracture after joint replacement.The femoral head was divided into 3 parts (lateral,inferior and medial region) with reference to anatomical markers on surface of the femoral head.After the position and drilling direction of the ring drill were determined,a circular drill was used to obtain the cylindrical cancellous bone columns with 10 mm in diameter and 10 mm in height.The data of cancellous bone columns in different regions were analyzed by Micro-CT scanning system,including bone volume fraction (BVF),trabecular space (Tb.Sp),trabecular thickness (Tb.Th),the number of trabecular number (Tb.N),the bone surface volume ratio (bone surface/bone volume,BS/BV),structural model index (SMI).Mechanical property differences of bone tissues in different regions were calculated by micro-finite element analysis.Results Bone mass in the elderly osteoporotic femoral head decreased,and there were significant differences in bone microstructure and mechanical properties in different regions of the femoral head.Bone microstructure and mechanical properties in medial region were obviously superior to those in lateral and interior region.Conclusions The bone structure and mechanical strength in medial region of the femoral head are obvious superior to those in lateral and inferior regions.The position for internal fixation should be fully considered during treatment of osteoporotic femoral neck fracture in clinic.
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Objective To investigate the structure and biomechanical property differences in different regions of the femoral head for elderly patients with femoral neck fractures, and to study its influence on internal fixation for fracture. Methods Twenty femoral head specimens were collected from elderly patients with femoral neck fracture after joint replacement. The femoral head was divided into 3 parts (lateral, inferior and medial region) with reference to anatomical markers on surface of the femoral head. After the position and drilling direction of the ring drill were determined, a circular drill was used to obtain the cylindrical cancellous bone columns with 10 mm in diameter and 10 mm in height. The data of cancellous bone columns in different regions were analyzed by Micro-CT scanning system, including bone volume fraction (BVF), trabecular space (Tb.Sp), trabecular thickness (Tb.Th), the number of trabecular number (Tb.N), the bone surface volume ratio (bone surface/bone volume, BS/BV), structural model index (SMI). Mechanical property differences of bone tissues in different regions were calculated by micro-finite element analysis. ResultsBone mass in the elderly osteoporotic femoral head decreased, and there were significant differences in bone microstructure and mechanical properties in different regions of the femoral head. Bone microstructure and mechanical properties in medial region were obviously superior to those in lateral and interior region. Conclusions The bone structure and mechanical strength in medial region of the femoral head are obvious superior to those in lateral and inferior regions. The position for internal fixation should be fully considered during treatment of osteoporotic femoral neck fracture in clinic.
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Journal of Medical Biomechanics was founded in 1986. As a technical periodical, the journal aims at reflecting the latest scientific and clinical achievement and progress in the field of biomechanics, and promoting academic exchange of biomechanics both in China and abroad. By June 2016, the journal has officially published a total of 31 volumes and 124 issues, and great progress has been achieved in its publishing quality and academic influence. In this article, the 30-year development of the journal is reviewed, and future work is prospected in the aspect of improving quality, digitalization and internationalization of the journal.
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With the increase of elderly population, more and more implant operations need to be performed in osteoporotic bone, while different forms of microdamage will be produced in peri-implant bone intraoperatively, including high- and low-density diffuse damages, as well as linear cracks. The length and location of the microcracks are the main factors in affecting the biomechanical performance of bone. Suppression of bone remodeling by bisphosphonates may lead to microdamage accumulation, which is often accompanied with the decrease of bone strength and the increase of bone fragility. Microdamage can be repaired by bone remodeling or mineralization to maintain the strength and structural integrity. Both remo- deling and mineralization can affect the bone quality and long-term implant stability. In this paper, we make a brief summary of some important issues and research progresses in this field.
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Humans , Bone RemodelingABSTRACT
Objective To evaluate the role of simvastatin in preventing and curing osteoporosis vertebrae by examining the effect from simvastatin on osteogenesis of the lumbar vertebrae in aging rats. Methods Sixty 15-month-old male SD rats were divided into six groups: the control group (injected with normal saline for three month), the baseline group (executed upon the gastric irrigation), the simavastatin-treated group (gastric irrigation with simavastatin at the dose of 5, 10, 20 and 40 mg/kg/d, respectively, for three month). L4 vertebrae were checked by Dual-Energy X-ray Absorptionmetry (DXA), Peri-quantiy CT (pQCT) and mineral apposition rates test. L5 vertebrae were checked by mechanical compression test. Results The value of DXA, pQCT and mineral apposition rate of 10 mg simvastatin group were slightly higher than that of the control group, but no significant differences were found between the two groups. The bone material properties of 10 mg and 20 mg simvastatin group were better than those of the control group, with no significant differences. Conclusions Although 10 mg simvastatin group (equivalent to 12~24 mg/d for human) seemed to have better properties than the other simvastatin groups, but there were no significant differences among these simvastatin-treated group. It is indicated that simvastatin doesn't play a positive role in promoting osteogenesis of the lumbar vertebrae in aging rats, so it may have no preventing or curative effect for osteoporosis of the lumbar vertebrae.
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Objective To investigate the effect of different perfusion flow rates on proliferation and osteoblastic differentiation of human mesenchymal stem cells (hMSCs) in large scale β-TCP (tricalcium phosphate) scaffold at perfusion bioreactor. Methods hMSCs isolated from iliac bone marrow aspiration were loaded into large scale β-TCP scaffold and cultured in perfusion bioreactor at the perfusion flow rate of 3, 6 or 9 mL/min for 15 days. The culture media were collected for D-glucose consumption assay every 3 days. After perfusion culture for 15 days, the cell-scaffold composites were harvested for assessment of cell viability by MTT colorimetric method, SEM observation and osteogenic gene expression by real-time PCR. Results The proliferation of hMSCs assayed by daily glucose consumption showed that at early stage of culture, cells proliferated faster at flow rate of 9 mL/min than at 3 or 6 mL/min (P<0.001); while at late stage of culture, cells proliferated faster at flow rate of 6 mL/min (P<0.05). The cell viability indicated that the cell-scaffold composites at flow rate of 6 mL/min exhibited the most viable cells (P<0.001). SEM indicated that all the macropores of the scaffold at different flow rates were filled with cellular layers. All cellular layers at flow rate of 3 mL/min were incompact, but that at 9 mL/min were compact; at flow rate of 6 mL/min, the cellular layers were either compact or incompact. Real-time PCR revealed that after perfusion culture for 15 days, the mRNA expression of osteobalstic genes including ALP and OP, were enhanced significantly at flow rate of 6 and 9 mL/min as compared to that at 3 mL/min (P<0.01); however, the 9 mL/min group presented the higher OC expression than 3 and 6 mL/min group (P<0.001). Conclusions At early stage of perfusion culture, the proliferation of hMSCs was promoted at flow rate of 9 mL/min, while at late stage, there was more viable cells in scaffolds at flow rate of 6 mL/min. The osteoblastic differentiation of hMSCs was facilitated with the increase of perfusion flow rate, which was attributed to the increased flow shear stress.
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Objective To study the repairing mechanism of mechanical microdamage around implants in the cortical bone of rats. Methods Thirty rats were divided into the ovariectomy group (OVX) and the sham group. At three months after the ovariectomy, a hole was drilled in the right tibial diaphysis by a metal pin. The rats were executed at 1, 2 and 4 weeks, respectively, after the hole drilling. The tetracycline and calcein labeling were performed before the execution. Bone segments containing the hole were stained with the basic fuchsin, embedded in the methylmethacrylate and cut into sections with thickness of 50 μm. Histomorphometric measurement was conducted on bone sections using Bioquant image analysis system. Results Bone resporpion cavities related to the microdamage occurred in both the OVX rats and the sham operated rats. The bone porosity and the number of bone resorption cavities were both greater in the OVX rats than that in the sham operated rats (P<0.05). In addition, the number of bone resorption cavities significantly increased with time after the surgery (P<0.05). Conclusions Increased bone porosity and resorption cavities in OVX rats may be related to the crack formation and the estrogen deficiency, which made the bone remodeling in the cortical bone of OVX rats more active. However, remarkably increased resorption cavities would reduce the bone strength and increase the risk of bone fracture.
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Bisphosphates as a first line preferred drug for curing osteoporosis has been used for a long time in clinic since it can inhibit the bone remodeling to decrease the risk of bone fracture and increase the bone density. But recent studies show that bisphosphates could cause the accumulation of microdamage to decrease bone quality. The long term use of bisphosphates may reduce the bone toughness and weaken the mechanical properties of bone. Some clinical reports have indicated that patients with osteoporosis tend to have non traumatic fractures after their use of bisphosphates. This article will review the effect of bisphosphates on the microdamage and mechanical properties of bone.
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<p><b>OBJECTIVE</b>To investigatre appropriate macroporous resins and the optimal technological parameters of the purification process of tartary buckwheat total flavonoids.</p><p><b>METHOD</b>Static and dynamic adsorption-desorption methods were adopted, and evaluated for separating efficiency by macroporous resins absorption rates, desorption rates.</p><p><b>RESULT</b>The DM -2 macroporous resin had the best separating efficiency. The best absorbed condition is H2O as solvent of extracts, diameter vs height: 1: 10, pH 3 - 4, absorption power: 3.0 mL x min(-1). The optimum adsorption condition is the volume of 50% ethanol 80 mL (approximately 5 BV (resin bed volume) as eluting solvent, pH 8, the desorption power: 3.0 mL x min(-1).</p><p><b>CONCLUSION</b>This technology is simple, quick and cost-effective, which is suitable for industrialization.</p>
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Fagopyrum , Chemistry , Flavonoids , Plants, Medicinal , Chemistry , Resins, Synthetic , Chemistry , Seeds , Chemistry , Technology, Pharmaceutical , MethodsABSTRACT
<p><b>OBJECTIVE</b>To clarify whether the acupoints of Zusanli (ST36) and Sanyinjiao (SP6) have specific actions other than non-acupoints to bone.</p><p><b>METHODS</b>Forty Sprague-Dawley female rats were divided into five groups: Sham operated (sham) group; Ovariectomized (OVX, model) group; non-acupuncture group; OVX, needling on Zusanli and Sanyinjiao (Acp-A) group; OVX, needling on the reverse sides of Zusanli and Sanyinjiao (Acp-B) group; OVX, periostineal stimulation on the same height as points of Zusanli and Sanyinjiao (Acp-C) group. The experiment was continued for 23 weeks and then all animals were sacrificed.</p><p><b>RESULTS</b>OVX had a significantly higher body weight and lower bone mineral density (BMD) on the lumbar vertebrae, total femora and tibiae than sham rats, however, Acp-A showed a higher BMD compared with the other OVX groups. On the other hand, bone weights, bone strength and bone morphometry such as trabecular volume, trabecular separation, labeled width and bone formation rate also showed the same improvements in Acp-A as compared to the other OVX rats.</p><p><b>CONCLUSION</b>The stimulation on Zusanli and Sanyinjiao specifically prevented the development of osteopenic rats compared with non-acupoints.</p>