Objective This study aims to evaluate the applicability of World Health Organization fracture risk assessment tool(FRAX) in Chinese postmenopausal women,and to assess the reliability of FRAX calculated without BMD.Methods This study was a retrospective cohort analysis of 2 314 postmenopausal Chinese women.All risk factors were collected from subjects requested in the FRAX assessment.Then FRAX was applied,retrospectively,with femoral neck T-score,to estimate 10-year probability of fracture of subjects.Moreover,the statistical correlation analysis pertaining to the application of FRAX and BMD when predicting fracture risk of Chinese postmenopausal women was also performed.The correlation between the fracture risk assessed by FRAX and the risk calculated by logistic regression algorithm was statistically evaluated in this Chinese population.Finally,the correlation among BMD,FRAX calculated with and without BMD was compared.Results There were significant differences between the FRAX results of each group divided by risk factors,except for drinking and smoking groups.Previous history fracture was the most influential factor.In the correlation analysis,both of the probability of major osteoporotic and hip fracture increased with the decline of BMD T-score.In addition,the assessment result of hip fracture generated by Logistic regression equation was consistent with the result by FRAX.For both major osteoporotic and hip fracture,FRAX measured without BMD was negatively correlated with BMD,and positively correlated with FRAX measured with BMD.Conclusion FRAX had practicability and effectiveness in the assessment of fracture risk for Chinese postmenopausal women.FRAX measured without BMD was consistent with FRAX measured with BMD.

Objective To develop an injective mixture of bone cement made with polymethylmethacrylate cement(PMMA) and calcium phosphate cement(CPC) and to become an ideal filling material for vertebroplasty and kyphoplasty based on the advantages of each material.Methods The experimental materials were injective bone cement PMMA and CPC.Firstly,the combined bone cement was made using the different mass ratio of PMMA and CPC,1∶2,1∶1,or 2∶1.Secondly,the standard test pieces with 6mm in diameter and 12mm in hight were made using the combined bone cement.Finally,a preliminary evaluation of physical and chemical properties of the mixed bone cement was carried out,i.e.,mechanical property,solidification temperature,solidification time,electron microscope scanning,X-ray diffraction,and animal muscle implantation experiment.Results The mixed bone cement(1∶1) had better physical and chemical properties than other proportions.Its compressive strength increased by about 120% higher than that of CPC.The solidification temperature was lower than 45 ℃,and solidification time was about 12-14 min.The microscopic structure of this mixed bone cement(1∶1) was similar to that of CPC.Seventy percent of the total pores were between 100-300μm and eyelet penetrations between the pores was mainly 10-20μm.The results of animal intramuscular implantation experiment demonstrated that the mixed bone cement(1∶1) had good biocompatibility,but the degeneration speed was slow.Conclusion The mixed bone cement(1∶1) can overcome the shortcomings of PMMA and CPC and have the advantage of each material.So this mixed bone cement is an ideal filling material for vertebroplasty and kyphoplasty.

To observe the microstructure of osteoporosis and normal trabecular bone and its effect on bone biomechanics. 4-month Lewis rats were randomly divided into OVX or sham group,each group has 6 animals,respectively. After 6 months of operation,all rats were sacrificed.The caudal vertebral were harvested and reconstructed by Micro-CT. In biomechanical evaluation,the axial failure test was accomplished on the caudal vertebrae.The volumetric BMD (vBMD) and tBMD of OVX group decreased significantly than that of sham group(P < 0.01).The bone volume fraction (BV/TV) and trabecular number(Tb.N) in OVX group also decreased significantly,while the bone area density (BS/BV),structure model index(SMI) and trabecular space(Tb.SP) significantly increased(P<0.05).Furthermore, the trabecular thickness(Tb.Th) had no significant difference in two groups.In biomechanical test,the maximum compressing strength and stiffness of trabecular bone in OVX group were lower than that in Sham group.The BV/TV and Tb.N were positive correlated with the strength and stiffness.Furthermore,SMI and Tb.SP were negative correlated with the strength and stiffness.The microstructure of trabecular bone affected its biomechanical properties.There are some correlations between microstructure and biomechanical properties.

*St. Joseph Hospital and the Maine Center for Osteoporosis Research and Education, 360 Broadway, Bangor, ME 00401, USA †The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04769, USA.