Micro-CT evaluation of femoral head samples' trabecular structure with femoral neck fracture

[Objective]To evaluate the trabecular three-dimensional structure of the femoral head specimens in neck fracture patients and non-fracture persons with series three-dimensional parameters based upon Micro-CT(micro-computed tomography) images.[Method]Fifteen cylindrical femoral bead's trabecular bone samples(diameter 15 mm,length 22～28 mm),six from normal person(27～36 years of age,normal group) and nine from femoral neck fracture patients(70～78 years of age,fracture group),were harvested from load-bearing region of fresh-frozen femoral head according to the roentgenograph.BMD were all measured by DEXA in these samples.After determining the resolution and threshold for the binary image,the two-dimensional and three-dimensional data of the trabecular structures were obtained in these femoral head's samples by using microcomputed tomography(micro-CT).And then,the upper 5 mm height parts(2 mm depth from the subchondral bone) of these samples were evaluated by three-dimensional parameters.These parameters included bone volume fraction(BVF,BV/TV),bone surface/bone volume(BS/BV) ratio,trabecular thickness(Tb.Th),trabecular number(Tb.N),trabecular separation(Tb.Sp),structure model index(SMI) and trabecular pattern factor(Tb.Pf).[Result]We obtained clear three-dimensional model of trabecular specimen.There was significant difference between fracture group and normal group in BV/TV(P=0.001),BS/BV(P=0.001),Tb.Th(P=0.01),Tb.Sp(P=0.025).The former had lower value in BV/TV(26.49%),BS/BV(39.73%),Tb.Th(15.43%) and higher value in Tb.Sp(25.27%) than that of the latter,whereas there was no significant difference in SMI,Tb.Pf and Tb.N between the two groups.The BMD values in each group were 0.154±0.04 g/cm~2 in normal group and 0.152±0.06 g/cm~2 in fracture group.And there was no significant difference between them(P0.05).[Conclusion]The values of three-dimensional parameters in old femoral neck fracture patient are different with that of normal persons in the loading region of the femoral head although there is no difference in BMD values between them.This may provide new evidence to predict osteoporotic femoral neck fracture.