2005, 20(1):1-4. DOI: 10.3871/j.1004-7220.2005.1.4.
Abstract:Objective This study evaluated the effects of sectioning the different scapholunate interosseous ligament(SLIL)subregions sequentially on the scapholunate interval, through which we can evaluate the role of different subregion of SLIL in maintain the normal scapholunate space, and provide a reference for the diagnosis of scapholunate dissociation. Method Twelve fresh cadaver upper extremities were used in this study. The wrist x-rays were taken in the intact state, after the proximal subregion of SLIL were cut, after the proximal and dorsal subregion of SLIL were cut, after the proximal and palmar subregion of SLIL were cut, after all of the SLIL were cut. Each x-rays were taken at neutral and ulnar deviation position, at rest and under stress. Scapholunate interval measurements were made at the mid-scapholunate joint. Comparison of the data was performed using one-way ANOVA. The level of significance was attributed to P<0.05. Results Sectioning of the proximal subregion of the SLIL did not change the scapholunate interval from the intact stage. Furthermore, additional sectioning of the dorsal or palmar subregion did not change scapholunate interval too. When the SLIL was sectioned completely, a small but statistically significant scapholunate interval change was noted. However, when the x-rays were taken at loaded wrist, the scapholunate intervals have significant changes compared with non-loaded wrist. The scapholunate interval has no significant difference between the neutral and ulnar position in all groups. Conclusions This study demonstrated that the proximal subregion of SLIL has no significant effect in maintaining the normal scapholunate relationship. When the SLIL was damaged severely, the abnormal scapholunate interval could be found more easily on wrist stress x-ray than non-stress x-ray. Thus, the x-ray taken at stress position was useful in the diagnosis of scaphoid lunate dissociation, especially when the SLIL was not damaged completely.
2005, 20(1):5-10. DOI: 10.3871/j.1004-7220.2005.01.10.
Abstract:Objectives To determine compressive force on anterior and posterior wall of the dura under posterior compression by ligamentum flavum with incremental compression ratios and different compression shapes in all posture. Methods Round bone window was drilled between C4 and C5 vertebral body of five fresh C2-C7 cervical spines. A compression-inducing pole (CIP) was made and slided into the bone window to simulate the hernia of ligamentum falvum. The compression ratio ranged from 10% to 60% of the canal diameter, a force record pole (FRP) and an anterior window were also made to record the compressive force caused by posterior compression. Results When the compression ratio is low (10%-20%), the compressive force is the biggest in left bending (30°). When the compression ratio is high (50%-60%), the compressive force is the biggest in flexion (30°). The compressive force on anterior wall of the dura is around 27.8% of that on posterior wall in all compression ratios, which enlarged with increase of the diameter of the CIP. Conclusion The force induced on the dura relate strongly with the compression ratio, the diameter of CIP and the posture of the cervical spine. Compressed spinal cords are easy to be deteriorated in full flexion and full extension.
2005, 20(1):11-13. DOI: 10.3871/j.1004-7220.2005.01.13.
Abstract:Objective The purpose of this study is to evaluate biomechanical character of continuous carbon-fiber reinforced polyolefin composites as hard tissue repair material. Methods Twenty-five rods of continuous carbon-fiber reinforced polyolefin were subjected to the tests of anti-bending, compressive strength, shear strength and flexural strength. The result included elastic modulus, tensile strength, Compressive strength, anti-bending strength, shear strength and poisson' s ratio. Results Elastic modulus: (43.33±1.17) GPa,tensile strength: (561.11±14.24) MPa,shear strength: (58.20±15.28) MPa,flexural strength: (715.86±19.26) MPa,Poisson' s ratio: 314±0.005, Elongation: (18.20±0.55) %, Compressive strength: (0.341.91±1.71) MPa. Conclusion This work revealed that the continuous carbon-fiber reinforced polyolefin composites have more ideal biomechanical Properties. It meet the biomechanical demends of hard tissue repair.
2005, 20(1):14-17. DOI: 10.3871/j.1004-7220.2005.01.17.
Abstract:Objective The model of base membrane of human cochlea is founded with the finite element analysis(ANSYS), there is certain scope of travel wave and largest amplitude of vibration on the base membrane of human cochlea among every frequency, so that the dynamical response has been researched. Methods This paper discribe the model of human cochlea with the Finite Element which named ANSYS. Results The different frequency is obtained under different situation of the model and different position of human cochlea. Conclusion The different frequency sound cause travel waves from the bottom of the base membrane of human cochlea to the top of the base membrane of human cochlea. The lower vibration frequency is, the further the travel wave transfers, the largest travel wave appears near the top of the base membrane of human cochlea.
2005, 20(1):18-24. DOI: 10.3871/j.1004-7220.2005.01.24.
Abstract:Objective To investigate from biomechanics the effect of acetabular coverage level on the osteoarthritis secondary affected by dysplasia. Methods The three dimensional finite element hip models of normal, dysplastic and over-covered were established to observe the regularity of stress distribution and the areas of stress concentration in dysplastic hip by nonlinear contact analysis. Results It was found that the pressure concentrated at the superior dome in all models, and some redundant high pressure occurred at the area near posterior-superior rim only in the dysplastic hip models. With the decreasing of the CE angle, contact pressure and peak stress increased remarkably, and the contact area decreased as well. But the changes of the pressure distribution and contact pressure were not significant when the CE angle was larger than 30°. Conclusion The biomechanics changes owing to decreasing of acetabular coverage level plays an important role in the osteoarthritis secondary affected by dysplasia.
2005, 20(1):25-27. DOI: 10.3871/j.1004-7220.2005.01.27.
Abstract:Objective Study on the mechanical properties of the normal and osteoarthritis knee joint cartilage of ordinary person. Methods Make the tensile test of one dimension on the normal and the morbid knee joint cartilage with Shimadzu AUTOGRAPH electronic universal testing machine. Results Got the data of the maximum load, the tensile ratio, the stress, the strain and the elastic modulu. To deal with the data of stress and strain by least-squares fit, the stress-strain formula and the curves were got. Conclusion The experimental results show that all the mechanical property indexes of the morbid group are obviously lower than those of the normal group.
2005, 20(1):28-31. DOI: 10.3871/j.1004-7220.2005.01.31.
Abstract:Objective To evaluate the biomechanics and clinical effects of phoenix-bitailed plate in treating thoracolumbar vertebrae burst fracture. Methods 8 burst fracture models in thoracolumbar vertebrae were made up from adult cadaver spinal specimens (T12～L2 ). Phoenix-bitailed plates were implanted into the models as actual operation. And they were tested under the axial and torsional load. Phoenix-bitailed plates were used to treat the thoracolumbar vertebrae burst fractures. And the curative effects were observed. Results The strain value of each tested point changed linearly according as the axial or torsional load changed even if the axial load increased to 600N or the torsion reached to 600N·cm. There is linear relation between the torsion and the torsion angle. The latter was only 6.26° when the former reached to 600N·cm. The clinical observation shows that the fixation with phoenix-bitailed plate is reliable. Conclusion The clinical application of phoenix-bitailed plate is worth generalizing for the fixation with it is very fastness and has high elasticity.
2005, 20(1):32-36. DOI: 10.3871/j.1004-7220.2005.1.36.
Abstract:Objective By biomechanical study about the stability of using 5 different types of pedicle screws (U1,U2,RF,SF1,SF2) on spinal specimen, to discuss the relationship between design parameter of screw,insertion torque,BMD and provide the theoretical foundation for clinical application of pedicle screw on osteoporotic patients; Method Six fixed lumbar cadaver specimens were used and divided into: normal group(ρ>1.00g/cm2, low BMD group (0.90g/cm2<ρ<1.00g/cm2)and osteoporosis group(ρ<0.90g/cm2). To determine the effects of the design parameter and the insertion torque of different screws on their fixation stability under various BMD by using WD-10A testing machine; Result There is a significant difference on the pullout strength of 5 different screws (U1,U2,RF,SF1,SF2) (P<0.05) . BMD of bone directly affect the intensity of fixation(according to the measured pullout strength). There is a significant difference among group of normal, low BMD and osteoporosis (P<0.05); The fixation intensity is in positive relation with insertion torque, the bigger the torque, the greater the fastness. And it is also in positive relation with BMD(r=0.936); Among specimens of low BMD, U2 has the greatest pullout strength among the 5 screws. Conclusion There is a close relationship between the type of screw, BMD and stability. BMD is in the positive relationship with pullout strength and insertion torque. In this study, the "U"-type screw displays the best fixation effect on specimen of low BMD
2005, 20(1):37-41. DOI: 10.3871/j.1004-7220.2005.01.41.
Abstract:Objective To predict the stress distribution of atlas under different pre-trauma postures by finite element method, and to deduce the sites of atlas fracture accordingly. Methods To set up the three-dimensional geometrically and mechanically finite element model and analyze the stress distribution of atlas under three different pre-trauma postures. Results In neutral posture, the high stress distribution occur at anterior arch and the junction between the posterior and lateral mass; in flexion posture, the high stress distribution occur at anterior arch;in extension posture, the high stress distribution occur at anterior arch and the junction between the posterior and lateral mass. Conclusion Since the high stress usually occur at the junction between the anterior arch and anterior nods, the junction between the anterior arch and lateral mass, and the junction between the posterior and lateral mass, these sites of atlas are likely to be the fracture sites. The type and sites of atlas fractures are highly dependent on the force vector applied to head, head posture at the time of trauma, atlas geometry and physical properties.
2005, 20(1):42-44. DOI: 10.3871/j.1004-7220.2005.1.44.
Abstract:Objective To set up three-dimentional reconstruction of acetabulum bone structure from CT scanned image in computer with sofeware of CAD. Methods CT images of 40 normal adult boney acetabula were obtained and processed with the algorithm of histogram-threshold segmenting and Kirsh boundary detection to get a binary contour image.The contour of scanned acetabulum were then used for three-dimentional reconstruction with CAD software. Results The computerized 3-Dreconstuction of acetabulum bone structure appeared to mimic the real anatomy of acetabulum. Conclusion Methods proposed in this paper can be used with high accuracy and reliability for further scientific study.
2005, 20(1):45-54. DOI: 10.3871/j.1004-7220.2005.01.54.
Abstract:Advances in computer-aided technology and its integration with biology, engineering, and information technology to tissue engineering application have developed a new field of computer-aided tissue engineering(CATE).This emerging field encompasses computer-aided design,imaging process, manufacturing, and solid freeform fabrication for modeling, designing, simulation, and manufacturing of biological tissue and organ substitutes. This paper presents some salient advances in this field, particularly in computer-aided tissue modeling, computer-aided tissue informatics, and computer-aided tissue scaffold design and fabrication. Methodologies of development of CATE modeling from high resolution non-invasive imaging and image-based 3D reconstruction, and various reconstructive techniques for CAD based tissue modeling generation will be described. The latest development in solid freeform fabrication to tissue engineering and a framework of bio-blueprint modeling for 3D cell and organ printing will also be introduced.
2005, 20(1):55-58. DOI: 10.3871/j.1004-7220.2005.01.58.
Abstract:The anatomy of the posterolateral structure of knee is complicated and includes the static and dynamic contribution of a number of ligamentous structures, such as the lateral collateral ligament,the popliteus tendon and the popliteofibular ligament ect, posterolateral structure injury can lead to posterolateral rotatory instability of tibia. This review summarizes the progression of the popliteofibular ligament in development of anatomy,macroscopic anatomy and biomechanics.
2005, 20(1):59-64. DOI: 10.3871/j.1004-7220.2005.1.64.
Abstract:Biomechanics of ligament of knee joint is a hotspot in recent years. Mechanical stimulus plays an important role in modulating ligament functions and in the healing and reconstruction of ligament. This paper has reviewed some recently advance focusing on the structure, features of mechanics and biochemistry, healing and reconstruction, effect of stress applying and immobilization of ligaments, and also on the cell differentiation by stress and contrast study between anterior cruciate ligament(ACL)and medial collateral ligament (MCL)