Radiographic Evaluation Of The Risk Assessment Of Hip Fragility Fractures

Part I Imaging study on the changes of hip bone mineral density and bone strength with gender and age in normal subjectsObjective: To investigate the relationship between femoral neck bone mineral density,bone cortical medulla ratio,bone marrow fat content with age and gender.Methods: A retrospective analysis was made of the imaging data of subjects with hip(pelvis)CT and dual-energy X-ray(DEXA)bone mineral density(BMD)examination in our hospital from November 2017 to February 2019.Subjects with hip fracture caused by severe violence,patients with pathological fracture caused by tumors and history of using chemoradiotherapy drugs should be excluded.The imaging data consisted of two parts:(I)298 subjects with femoral neck bone mineral density(FN-BMD)measured by DEXA,femoral neck cortical medullary ratio(FN-CMR)measured by CT;(II)MR scans were performed in 192 subjects for femoral neck bone marrow fat content(FN-BMF).These subjects are divided into five groups by age: ≤ 44,45-54,55-64,65-74,≥ 75 years old.Statistical analyses were performed using SPSS 22.0 software.The correlations between FN-BMD,FN-CMR and FN-BMF,the differences between different genders,same gender different age groups and same age group different gender were analyzed.P<0.05 was considered statistically significant.Results: 1.FN-BMD and FN-CMR are decreased with age,and the correlation coefficient r was-0.652,-0.599;FN-BMD and FN-CMR were higher in men than in women,but women’s decline rate with age is significantly higher than that of men.what’s more the age at which female FN-CMR began to decrease was earlier than that of males;2.FN-BMF increased with age,and the correlation coefficient r = 0.784;Before the age of 65,FN-BMF in Male are higher than in female,but significantly lower than female after it;however,the growth rate of females’ FN-BMF is higher than that of males.Conclusion: In normal people,FN-BMD and FN-CMR are decreased with age,while FN-BMF show an upward trend,and the growth/decution rate of female is higher than that of male.To understand the changes of FN-BMD,FN-CMR and FN-BMF with gender and age in normal people,has reference value for the quantitative assessment of hip fragility risk.Part II: Correlation analysis between fragility fracture of hip joint and bone cortical medulla ratio and bone mineral densityObjective: To investigate the relationship between hip brittle fracture and bone cortical medulla ratio and bone mineral density.Methods: A retrospective analysis of patients’ hip(pelvic)CT,and dual-energy X-ray(DEXA)bone mineral density.All patients aged ≥45 years were hospitalized in our hospital from2017.11 to 2019.2.Patients with hip fractures should be excluded from patients with hip fractures due to severe violence and those with pathological fractures such as tumors and history of radiotherapy.A total of 338 patients were enrolled.The femoral neck cortical medulla ratio(FN-CMR)was measured by CT in the contralateral femoral neck region of all fracture patients as an indicator of cortical thickness.The femoral neck bone mineral density(FN-BMD)was measured with DEXA to understand the degree of osteoporosis.I.According to the fracture history,they were divided into fracture group(n=107),non-fracture group/control group(n=231),and divided into four age groups(group 1~4): 45-54,55-64,65~74,≥75 years old.The difference of FN-BMD and FN-CMR between the two groups was compared by one-way ANOVA or rank sum test(P<0.05 was considered statistically significant),and the chi-square test was used to compare the gender distribution and age group composition ratio between the two groups.The difference of FN-BMD and FN-CMR between the fracture group and the control group of same sex different age groups 、same age group different sex was compared by one-way ANOVA or rank sum test,P<0.05 was considered statistically significant.II.Statistically significant variables were used for logistic regression analysis to analyze the risk factors of hip fracture at age ≥ 45,compare the relative importance of different factors,establish a corresponding prediction model,and then perform ROC curve analysis based on the analysis results.Results: 1.The ratio of age group compositionn between fracture group and control group is not exactly the same(p<0.001).In fracture group,the proportion of women was significantly higher than that of the male(p=0.007),and FN-BMD 、FN-CMR of the patients with hip fracture were significant lower than non-fracture group(p<0.001,0.002);2.FN-BMD has limitations on the risk assessment of hip brittle fracture in ≥45 years old men and ≥65years old women(p>0.05);FN-CMR was statistically different between the fracture group and the non-fracture group at all ages(p<0.05),except for men aged 65-74.3.By logistic regression analysis,age and FN-CMR are Risk factors for hip fragility fractures in people over 45 years old(area under the ROC curve of the prediction equation is 0.868);FN-CMR is more valuable than FN-BMD for predicting the risk of hip fragility fractures in people over45 years of age(The area under the ROC curve is 0.817,0.599).Conclusion: The bone cortical medulla ratio of the femoral neck can better reflect the change of femoral neck cortical thickness.The decrease of bone strength caused by the decrease of bone cortical medulla ratio is an important factor for the femoral neck fracture,and FN-CMR is an effective index for predicting the risk of brittle fracture of the hip joint.