• 제목/요약/키워드: bone strength

검색결과 499건 처리시간 0.028초

저강도 타이치 운동이 시설거주노인의 체력, 골밀도 및 골절위험도에 미치는 효과 (Effects of Tai Chi Exercise on Physical Fitness, Bone Mineral Density, and Fracture Risk in Institutionalized Elderly)

  • 김현리;소희영;송라윤
    • 기본간호학회지
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    • 제17권3호
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    • pp.334-342
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    • 2010
  • Purpose: The purpose of this study was to examine the effects of Tai Chi exercise on flexibility, balance, walking ability, muscle strength, bone mineral density, and fracture risk in institutionalized elders. Method: A quasi-experimental pretest-posttest design with a nonequivalent comparison group was utilized, and 53 older adults living in one institution were recruited and assigned to one of two groups, experimental group (18) or comparison (20). Both groups completed posttest measures at 6 months. There was a 31% rate of dropouts. Tai Chi exercise was provided twice a week for 24 weeks. Outcome measurements were conducted by a physiotherapist at a university hospital health promotion center who did not know the group assignment. Results: At 6 months, the experimental group had significantly greater grip strength(t=2.12, p=.04), back muscle strength (t=2.42, p=.02), balance (t=5.31, p<001), and flexibility (t=3.57, p<.001). They also showed significantly greater bone mineral density of lumbar spine and femur, and reduced fracture risk. Conclusion: Tai Chi exercise was safely and effectively used with institutionalized elders for 6 months and significantly improved physical fitness, bone mineral density along with a reduction in fracture risk. Whether Tai Chi exercise would lead to prevention of fall episodes and fall related fractures in this population will require further study.

Performance analysis of bone scaffolds with carbon nanotubes, barium titanate particles, hydroxyapatite and polycaprolactone

  • Osfooria, Ali;Selahi, Ehsan
    • Biomaterials and Biomechanics in Bioengineering
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    • 제4권1호
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    • pp.33-44
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    • 2019
  • This paper presents a novel structural composition for artificial bone scaffolds with an appropriate biocompatibility and biodegradability capability. To achieve this aim, carbon nanotubes, due to their prominent mechanical properties, high biocompatibility with the body and its structural similarities with the natural bone structure are selected in component of the artificial bone structure. Also, according to the piezoelectric properties of natural bone tissue, the barium titanate, which is one of the biocompatible material with body and has piezoelectric property, is used to create self-healing ability. Furthermore, due to the fact that, most of the bone tissue is consists of hydroxyapatite, this material is also added to the artificial bone structure. Finally, polycaprolactone is used in synthetic bone composition as a proper substrate for bone growth and repair. To demonstrate, performance of the presented composition, the mechanical behaviour of the bone scaffold is simulated using ANSYS Workbench software and three dimensional finite element modelling. The obtained results are compared with mechanical behaviour of the natural bone and the previous bone scaffold compositions. The results indicated that, the modulus of elasticity, strength and toughness of the proposed composition of bone scaffold is very close to the natural bone behaviour with respect to the previous bone scaffold compositions and this composition can be employed as an appropriate replacement for bone implants.

역학적 강도 분석을 이용한 저강도 초음파의 조사 부위의 골다공증 골절 방지 효과 평가 (In vivo Evaluation of Osteoporotic Fracture Prevention of the site to which low Intensity Ultrasound is Irradiated using Mechanical Strength Simulations)

  • 우대곤;김치훈;박지형;고창용;김한성;김진만;김상희;임도형
    • 대한의용생체공학회:의공학회지
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    • 제30권2호
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    • pp.135-141
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    • 2009
  • Purpose: The aim of present study is to evaluate a possibility of clinical application for the effect of low intensity ultrasound stimulation (LIUS) in mechanical characteristics of bone on osteoporotic fractures prevention. Materials and Methods: Eight virgin ICR mice (14 weeks old, approximate weight 25g) were ovariectomized (OVX) to induce osteoporosis. The right hind limbs were then stimulated with LIDS (US Group), whereas left hind limbs were not stimulated (CON Group). Both hind limbs of all mice were scanned by in-vivo micro-CT to acquire two-dimensional (2D) images at 0 week before stimulation and 3 weeks and 6 weeks after stimulation. Three-dimensional (3D) finite element (FE) models generated by scanned 2D images were used to determine quantitatively the effect of LIUS on strength related to bone structure. Additionally, distributions of Hounsfield units and elastic moduli, which are related to the bone quality, for the bones in the US and CON groups were determined to analyze quantitatively a degree of improvement of bone qualities achieved by LIUS. Results: The result of FE analysis showed that the structural strength in US Group was significantly increased over time (p<0.05), while that in CON Group was statistically constant over time (p>0.05). High values of Hounsfield units obtained from voxels on micro-CT images and high values of elastic moduli converted from the Hounsfield units were dominantly appeared in US Group compared with those in CON Group. Conclusion: These finding indicated that LIUS would improve the mechanical characteristics of osteoporotic bone via the effects of bone structure (bone strength) and quality (Hounsfield unit and elastic modulus). Therefore, the LIUS may decrease effectively the risk of osteoporotic fracture in clinics.

An Experimental Study on the Biomechanical Effectiveness of Bone Cement-Augmented Pedicle Screw Fixation with Various Types of Fenestrations

  • Yoon, Sang Hoon;Lee, Sang Hyung;Jahng, Tae-Ahn
    • Journal of Korean Neurosurgical Society
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    • 제65권6호
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    • pp.779-789
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    • 2022
  • Objective : To analyze the effects of the number and shape of fenestrations on the mechanical strength of pedicle screws and the effects of bone cement augmentation (BCA) on the pull-out strength (POS) of screws used in conventional BCA. Methods : For the control group, a conventional screw was defined as C1, a screw with cannulated end-holes was defined as C2, a C2 screw with six pinholes was defined as C3, and the control group type was set. Among the experimental screws, T1 was designed using symmetrically placed thru-hole type fenestrations with an elliptical shape, while T2 was designed with half-moon (HM)-shaped asymmetrical fenestrations. T3 and T4 were designed with single HM-shaped fenestrations covering three pitches and five pitches, respectively. T5 and T6 were designed with 0.6-mm and 1-mm wider fenestrations than T3. BCA was performed by injecting 3 mL of commercial bone cement in the screw, and mechanical strength and POS tests were performed according to ASTM F1717 and ASTM F543 standards. Synthetic bone (model #1522-505) made of polyurethane foam was used as a model of osteoporotic bone, and radiographic examinations were performed using computed tomography and fluoroscopy. Results : In the fatigue test, at 75% ultimate load, fractures occurred 7781 and 9189 times; at 50%, they occurred 36122 and 82067 times; and at 25%, no fractures occurred. The mean ultimate load for each screw type was 219.1±52.39 N for T1, 234.74±15.9 N for T2, 220.70±59.23 N for T3, 216.45±32.4 N for T4, 181.55±54.78 N for T5, and 216.47±29.25 N for T6. In comparison with C1, T1, T2, T3, T4, and T6 showed significantly different ultimate load values (p<0.05). However, when the values for C2 and the fenestrated screws were evaluated with an unpaired t test, the ultimate load value of C2 significantly differed only from that of T2 (p=0.025). The ultimate load value of C3 differed significantly from those of T1 and T2 (C3 vs. T1 : p=0.048; C3 vs. T2 : p<0.001). Linear correlation analysis revealed a significant correlation between the fenestration area and the volume of bone cement (Pearson's correlation coefficient r=0.288, p=0.036). The bone cement volume and ultimate load significantly correlated with each other in linear correlation analysis (r=0.403, p=0.003). Conclusion : Fenestration yielded a superior ultimate load in comparison with standard BCA using a conventional screw. In T2 screws with asymmetrical two-way fenestrations showed the maximal increase in ultimate load. The fenestrated screws can be expected to show a stable position for the formation of the cement mass.

생체골의 열전도성 및 열처리된 골의 염전력 변화에 대한 실험적 연구 (Experimental Studies on Heat Conductivity of Human Bone and Torsional Strength of Pasteurized Porcine Tibia)

  • 박일형;김신근;신동규;인주철
    • 대한골관절종양학회지
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    • 제1권1호
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    • pp.7-16
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    • 1995
  • 인체골 4 시편(specimen)과 돼지 경골 25쌍을 이용하여, 생체골의 열전도성 측정과 열처리후 열처리온도와 시간에 따른 골의 염전력을 실험한 결과를 요약하면 다음과 같다. 인체골에 있어서 골수강을 제거하지 않고 $60^{\circ}C$의 항온식염수에서 열처리하면, 골심부의 온도가 $20^{\circ}C$에서 $58^{\circ}C$에 도달하는데 소요된 시간은 경골근위부가 32분 50초, 대퇴골 원위부가 30.분, $80^{\circ}C$ 항온조에서는 경골근위부가 12분 50초, 대퇴골 원위부가 11분 10초 소요되었다. 돼지 경골간부의 피질골내부(endosteum)에 열전대를 부착하고 뼈 양끝을 밀봉하여 같은 실험을 행한 결과 $50^{\circ}C$까지는 시간에 비례해서 일정한 비율로 온도상승이 이루어 졌으며, $20^{\circ}C$에서 $58^{\circ}C$에 이르는 시간이 $60^{\circ}C$ 항온조에서는 7분, $70^{\circ}C$에서는 3분 30초, $80^{\circ}C$에서는 2분이었다. 따라서 임상에서 골수강을 제거 후 장골의 간부(shaft) 만을 항온조에 달굴때는 골구강내에도 데워진 심염수로 가득차게 되므로 상기 시간의 절반이 못되는 짧은 시간내에 피질골의 내부가 $58^{\circ}C$에 이르리라고 판단되었다. 골수강을 소파하지 않은 돼지 경골을 각각 4쌍씩 우측만을 $60^{\circ}C$ 35분, $80^{\circ}C$ 15분 열처리한 후 실험군의 최대염전력은 대조군과 비교할 때 +7.0%, -5.1%, -3.2%, -4.2%의 변화가 있었고, $80^{\circ}C$ 15분 열처리후는 -4.3%, -3.8%, -1.4%(1예는 실험 오류로 제외됨)의 변화가 있었다. 골수강을 완전 제거한 되재 경골을 각각 4쌍씩 우측만을 $60^{\circ}C$, $70^{\circ}C$, $80^{\circ}C$에서 15분 열처리 후 실험군의 최대염전력은 대조군과 비교할 때 -3.4%, -4.2%, -0.7%, +2.7%의 변화가 있었고, $70^{\circ}C$ 15분 열처리후는 -2.8%, -3.9%, -2.1%(1예는 실험 오류로 제외됨)의 변화가 있었으며, $80^{\circ}C$ 15분 열처리후는 +5.2%, -4.4%, -2.9%, -0.3%의 염전력 변화가 있었다. 그러므로 골수강을 제거하지 않고 $80^{\circ}C$ 35분, $60^{\circ}C$ 15분 열처리 하거나, 골수강을 완전소파 후 $60^{\circ}C$ 15분, $70^{\circ}C$ 15분, $80^{\circ}C$ 15분 열처리해서는 각군사이에 염전력의 유의한 차이는없었다. 이상의 결과로 돼지 경골의 경우 $60^{\circ}C$ 항온에서는 35분까지, $80^{\circ}C$이하의 항온에서는 15분까지 열처리하여도 골강도에는 거의 영향이 없는 것으로 나타났다.

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돼지 뼈를 이용한 Bone Ash 제조 및 청자 Bone 소지에 관한 연구 (A Study on the Preparation of Bone Ash and Celadon Bone Body Using Pig Bone)

  • 정재진;이상희;이용석;이병하
    • 한국세라믹학회지
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    • 제44권1호
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    • pp.12-17
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    • 2007
  • Recently, Korean food culture has westernized and the consumption of meat has been increased. As a result an enormous amount of disposal of bone is generated and most of them are buried without reutilization. By making bone ash using pig bone, the possibilities of application are examined. The purpose of this study is to establish a manufacturing process of bone ash for the celadon bone body using pig bone. The calcination of the pig bone was mostly to change to the calcium phosphate hydroxide $(Ca_5(PO_4)_3OH)$. The celadon body mixed with pig bone ash 8%, $CaCO_3$ 9%, when fired at $1240^{\circ}C$ under reduction atmosphere, shows 0.1% of water absorption, 65.23 MPa of bending strength.

Assessment of Xenogenic Bone Plate and Screw using Finite Element Analysis

  • Heo, Su-young;Lee, Dong-bin;Kim, Nam-soo
    • 한국임상수의학회지
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    • 제35권3호
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    • pp.83-87
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    • 2018
  • The aim of this study was to evaluate the biomechanical behavior of xenogenic bone plate system (equine bone) using a three-dimensional finite element ulna fracture model. The model was used to calculate the Von Mises stress (VMS) and stress distribution in fracture healing periods with metallic bone plate and xenogenic bone plate systems, which are installed while the canine patient is standing. Bone healing rate (BHR) (0%) and maximum VMS of the xenogenic plate was similar to the yield strength of equine bone (125 MPa). VMS at the ulna and fracture zones were higher with the xenogenic bone plate than with the metallic bone plate at BHRs of 0% and 1%. Stress distributions in fracture zone were higher with the xenogenic bone plate than the metallic bone plate. This study results indicate that the xenogenic bone plate may be considered more beneficial for callus formation and bone healing than the metallic bon plate. Xeonogenic bone plate and screw applied in clinical treatment of canines may provide reduced stress shielding of fractures during healing.

Bone mineral density deficits in childhood cancer survivors: Pathophysiology, prevalence, screening, and management

  • Kang, Min Jae;Lim, Jung Sub
    • Clinical and Experimental Pediatrics
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    • 제56권2호
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    • pp.60-67
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    • 2013
  • As chemotherapy and other sophisticated treatment strategies evolve and the number of survivors of long-term childhood cancer grows, the long-term complications of treatment and the cancer itself are becoming ever more important. One of the most important but often neglected complications is osteoporosis and increased risk of fracture during and after cancer treatment. Acquisition of optimal peak bone mass and strength during childhood and adolescence is critical to preventing osteoporosis later in life. However, most childhood cancer patients have multiple risk factors for bone mineral loss. Cancer itself, malnutrition, decreased physical activity during treatment, chemotherapeutic agents such as steroids, and radiotherapy cause bone mineral deficit. Furthermore, complications such as growth hormone deficiency and musculoskeletal deformity have negative effects on bone metabolism. Low bone mineral density is associated with fractures, skeletal deformity, pain, and substantial financial burden not only for childhood cancer survivors but also for public health care systems. Thus, it is important to monitor bone health in these patients and minimize their risk of developing osteoporosis and fragility fractures later in life.

Fabrication and Characterization of Novel Electrospun PVPA/PVA Nanofiber Matrix for Bone Tissue Engineering

  • Franco, Rose-Ann;Nguyen, Thi Hiep;Lee, Byong-Taek
    • 한국재료학회:학술대회논문집
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    • 한국재료학회 2011년도 춘계학술발표대회
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    • pp.51.2-51.2
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    • 2011
  • A novel electrospun nanofiber membrane was fabricated using combined poly (vinylphosphonic acid) (PVPA) and polyvinyl alcohol (PVA) intended for bone tissue engineering applications. PVPA is a proton-conducting polymer used as primer for bone implants and dental cements to prevent corrosion and brush abrasion. The phosphonate groups of PVPA have the ability to crosslink and attach itself to the hydroxyapatite surface facilitating faster integration of the biomaterial to the bone matrix. PVA was combined with PVPA to provide hydrophilicity, biocompatibility and improve its spinnability. To improve its mechanical strength, PVPA/PVA and neat PVA mixtures were combined to produce a multilayer scaffold. The physical and chemical properties of the of the fabricated matrix was investigated by SEM and TEM morphological analyses, tensile strength test, XRD, FT-IR spectra, swelling behavior and biodegradation rates, porosity and contact angle measurements. Biocompatibility was also examined in vitro by cytotoxicity and cell proliferation studies with MTT assay and cell adhesion behavior by SEM and confocal microscopy.

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