RESUMO
BACKGROUND:Impact mechanics properties of thoracic vertebra cancellous bone should be understood in treating osteoporosis,bone remodeling,bone reconstruction,as well as fixator selection for thoracic vertebral fracture.Most of previous studies concerning youth and the elderly bodies alone,reports regarding impact of thoracic vertebra cancellous bone mechanical properties are few.OBJECTIVE:To perform impact experiment to the normal people youth and the elderly fresh corpse thoracic vertebra cancellous bone to survey the impact mechanical properties,and to definite whether the impact mechanical properties of thoracic vertebra trabecular bone have difference between youth and the elderly people.METHODS:Experimental samples were from 4 normal fresh corpse,aged 20,25,70 and 75 years,were provided by Department of Anatomy,Norman Bethune Medical University.Spinal column thoracic vertebra T_(3-12) specimen were obtained from corpse within 1 hours and cut into 40 mm×6 mm×6 mm pieces,with 20 test pieces in each group.The impact experiment was performed using energy liberation method at room temperature under 28 ℃.After experiment,the impact energy was displayed automatic on testing machine,and the impact toughness was calculated by mechanical formula,and the morphology of fracture surface was observed.RESULTS AND CONCLUSION:The impact energy and impact toughness of the youth group was obviously greater than that of the elderly group (P＜0.05).Majority of the fracture surfaces were comminuted,minority were transverse or oblique fracture.The macroscopic observation showed that trabecular arranged compact in the thoracic vertebra cancellous bone of the youth group,which was sparse arrangement and presented with senile osteoporosis in the elderly group.It demonstrated that the impact mechanics properties of thoracic vertebra cancellous bone are different between the youth and elderly groups,and osteoporosis changes impact mechanics properties in the elderly people.
RESUMO
Objective To compare the mechanical properties of animal knee lateral collateral ligament tensile between the normal and atherosclerotic animal model of osteoarthritis,and to identify if there are effects of osteoarthritis on the animal knee lateral collateral ligament tensile mechanical properties.Methods The experimental rats were provided by the Changchun High Medical Center for animal experiments.The 6-month-old male rats were the copying model of osteoarthritis.The tensile experiments at electron Shimadzu universal testing machine was carried out on ten of normal and pathological specimens.The speed of the tensile experiments was 5mm/min.Experimental data were processed by polynomial least square method.Results The tensile maximum load of normal control group was(26.12?4.00)N,maximum stress was(40.93?6.71)MPa,maximum displacement was(3.08?0.77)mm,and maximum strain was(9.51?2.36)%.The tensile maximum load of model group was(12.05?2.07)N,maximum stress was(21.28?4.17)MPa,maximum displacement was(2.32?0.56)mm,and maximum strain was(7.04?1.79)%.Conclusion The tensile performance of normal control group was significantly greater than that of the model group(P