DEXA测量松质骨BMD与其生物力学相关性

Relationship between BMD and biomechanics of femoral head in human

目的研究人股骨头主要承重区骨密度(Bone Mineral Density,BMD)与骨生物力学相关性;探讨双能X线骨密度仪(Dual Energy X-Ray Absorptiometry,DEXA)对股骨颈骨折治疗的临床参考价值。方法收集2002年11月至2004年12月收治的股骨颈骨折患者行假体置换术取下的股骨头共42例。采用双能X线骨密度仪(Dual Energy X-Ray Absorptiometry,DEXA)测量离体股骨头主要承重区BMD值;在股骨头主要承重区取柱状试件,行纵向压缩力学试验,记录极限应力、极限能量和弹性模量。利用SPSS12.0软件对数据进行正态分布检验后,采用双变量相关性分析法(Pearson相关分析法或Spearman相关分析法)判定BMD与极限应力、极限能量和弹性模量的相关性。结果(1)BMD测量值在0.39～1.05g/cm2之间,呈正态分布,为0.71±0.17g/cm2;(2)极限应力在2.09～23.49MPa范围之间,呈非正态分布,为9.69±6.36MPa;(3)极限能量在2.04～11.76J范围之间,呈非正态分布,为5.45±2.80J;(4)弹性模量在16.59～218.58MPa之间,呈非正态分布,为88.89±48.45MPa;(5)人股骨头主要承重区BMD与极限应力具有线性正相关性,rs=0.765,P<0.001;(6)人股骨头主要承重区BMD与极限能量具有线性正相关性,rs=0.717,P<0.001;(7)人股骨头主要承重区BMD与弹性模量具有线性正相关性,rs=0.669,P<0.001;结论BMD与极限应力、极限能量和弹性模量具有线性正相关性,通过测量股骨头的BMD可以初步预测骨的抗压强度和硬度。

Objective 1 . To explore the relation between bone mineral density （BMD） and bone biomechanics of femoral head （FH）. 2.To discuss the clinical value of BMD in the treatment of FNF.Methods All the samples were collected from patients suffering from femoral neck fracture and receiving operation of total hip replacement （THR）. All the 42 samples were frozen immediately after extraction from patients who accepted THR. The BMD was measured by Dual Energy X-Ray Absorptiometry（DEXA）. Then fourty-two bone blocks which resected from the primary bearing area of femoral head were measured by mechanical test to obtain the ultimate stress, ultimate energy and elastic modulus. All the data of BMD and bone biomechanics were expressed in x± s. The correlation of them was analysed by Bivariate Correlation after normal deviation test by spss 12. Results The results of BMD were between 0.39-1.05 g/cm^2 ,x±s was 0.71 ± 0.17 g/cm^2 ;the results of ultimate stress were between 2.09- 23.49 MPa,x ± s was 9.69 ± 6.36 MPa; the results of ultimate energy were between 2.04-11.76 J, x ±s was 5.45±2.80 J;the results of Modulus of elasticity were between 16.59-218.58 MPa, x ± s was 88.89 ± 48.45 MPa;the positive linear correlation between BMD and ultimate stress was significant, r, = 0.765, P 〈 0.001 ;the positive linear correlation between BMD and uhimate energy was significant, r, = 0.717, P 〈 0.001 ;the positive linear correlation between BMD and Modulus of elasticity was significant, r = 0.669, P 〈 0.001 ; Meanwhile, As the BMD value decreased,trabecular pattern of the samples became fragile and porous and the bone collagen fiber became loose and ruptured finally. Conclusions There is a significant positive linear correlation between BMD and ultimate stress,ultimate energy and EM. The properties of biomechanics can be obtained by measuring BMD.