Changes of bone mineral density and structural parameters of femoral neck in fragile femoral neck fracture / 中华老年医学杂志

ABSTRACT

Objective To study the changes of bone mineral density (BMD) and structural parameters of femoral neck in fragile femoral neckfracture,and to investigate the relationship between the changes and occurrence of fragile fracture of femoral neck.Methods 102 patients were divided into fracture group (n=59) and non-fracture group (n=43).There were 18 males and 41 females [[mean age (74.0±9.3) yrs,ranged 53-88 yrs] in fracture group and 16 males and 27 females [mean age (64.3±9.9)] yrs,ranged 50-82 yrs in non-fracture group.CT scan and BMD in the femoral neck were collected in all patients.The structural parameters of the femoral neck in CT scan were measured with medical image analysis software.Results BMD was lower,cortical thickness of femoral neck (FNCT) was thinner and the ratio (FNCT/FNW) of cortical thickness (FNCT) over femoral neck width (FNW) was lower in fracture group than in non-fracture group (all P＜0.001),but there were no statistically significant differences in femoral neck width (FNW) and femoral medullary cavity width (FMCW) between the two groups (both P＞0.05).The BMD of femoral neck was markedly decreased in the fracture group as compared with the non-fracture group in patients aged 50-64 yrs (P ＜0.05),and there were no statistically significant differences in the changes of the femoral neck BMD between the two groups in patients aged over 65 yrs (P＜0.05).In both of patients aged 50-64 yrs and more than 65 yrs,FNCT was thinner and ratio of FNCT/FNW was lower in the fracture group than in the non-fracture group (both P＜0.05).The patients with osteopenia and osteoporosis had thinner FNCT and lower ratio of FNCT/FNW in the fracture group than in the non-fracture group of the patients with osteopenia and osteoporosis (both P＜ 0.01).Conclusions Lower BMD and thinner cortical thickness of femoral neck are closely related to the fragile fracture of femoral neck.The phase of femoral neck BMD rapid decline is mainly in the age of 50-65 yrs,which is consistent with the risk assessment for fragile fracture in femoral neck.The decrease of cortical thickness of femoral neck on FNCT is the main factor for the decreased femoral neck strength in patients aged over 65 yrs,which is also an important factor for the fragile fracture of femoral neck in the elderly aged over 65 yrs.