The Clinical Application Of Femur Strength Index Measured By DXA

Aim:To compare the difference of the bilateral proximal femoral strength,to assess the correlations between the femur strength and the strength index(SI) of the heel in Chinese,and to provide theory basis for the clinical application of HSA system.Method:We measured the bone mineral density(BMD) of the bilateral proximal femurs(i.e.,total hip,femoral neck,Ward's triangular area and trochanter) using dual energy X-ray absorptiometry(DXA) in 1637 Chinese(1164 females aged 20～93years,473 males aged 20～86 years),and speed of sound(SOS),broadband ultrasound attenuation(BUA),and a calculated SI of the left os calcis using QUS in 90 Chinese females aged 20～71 years.A series of structural variables,including femoral neck cross-sectional area(CSA),cross-sectional moment of inertia(CMSI), HAL(hip axel length),section modulus(Z) and FSI(femur strength index) were assessed automatically with hip strength analysis(HSA) DXA software.Results:①The precision for each variables of the bilateral proximal femoral strength was 1.7%～4.2%.The precision for SI,SOS and BUA was 1.8%,0.4%and 2.9%, respectively.②No significant differences(P＞0.05) in each variables of strength between bilateral femoral were found no matter in males,nor in females,nor in pre-menopausal females,nor in postmenopausal.③Moderate correlations were found between the bone mineral density(BMD) of left femur and left heel stiffness in females(r=0.34～0.61,P＜0.001).To some extent,correlations were observed between CSA,CSMI,Z of femur neck and BUA,SOS,SI of calcaneal bone(r=0.24～0.59,P＜0.05).Nevertheless,there was no correlation between HAL,FSI assessed by DXA and heel strength calculated by QUS in this research(P＞0.05).Conclusion:No significant differences in each variables of strength between bilateral femoral were found in Chinese,which provide theory basis for assessing the dangerous of bone fracture in osteoporosis(OP);the reasons of no-correlation between HAL,FSI of femur and SI,BUA,SOS of heel will need further research.