Classification of Hip Fragility Fractures in Older Adults Using an Ultrasonic Device

Accurate measurement of cortical bone parameters may improve fracture risk assessment and help clinicians on the best treatment strategy. Patients at risk of fracture are currently detected using the current X-Ray gold standard DXA (Dual XRay Absorptiometry). Different alternatives, such as 3D X-Rays, Magnetic Resonance Imaging or Quantitative Ultrasound (QUS) devices, have been proposed, the latter having advantages of being portable and sensitive to mechanical and geometrical properties. The objective of this cross-sectional study was to evaluate the performance of an improved ultrasonic device (Bi-Directional Axial Transmission, BDAT) with older adults with or without hip fragility fracture. The device, positioned at one-third distal radius, provides two velocities denoted VFAS and VA0 as well as two parameters are obtained from an inverse approach: Ct.Th (cortical thickness) and Ct.Po (cortical porosity), along with their ratio Ct.Po/Ct.Th. The areal bone mineral density (aBMD) was obtained using DXA at the hip. Fifty two patients (40 women, 12 men) were included in this study, in connection with local health services. Age ranged from 51 to 98 years, while body mass index (BMI) ranged from 22 to 36 kg.m−2. Failure rate was found to be 4% (2 patients) lower than in previous studies, mainly due to the guiding interface improvement and quality monitoring. Two groups were considered: 41 patients without fragility fractures (68±11 years), 11 with fragility femoral fractures (80±9 years). Odds ratio (OR) and the area under the ROC curve (AUC) were calculated using multivariate Partial Least Square discrimination analyses with Leave-One-Out Cross-Validation (PLS-LOOCV). We found the combination of significant ultrasound parameters (VA0, Ct.Th, Ct.Po/Ct.Th) to be predictive for fragility femoral fractures (AUC=0.72), above aBMD total femur values (AUC=0.63). When adjusted with age and gender, values for significant parameters were equal to AUC=0.82. These promising results have to be confirmed with a larger sample size. The fracture risk assessment using this ultrasound device in older patients suggests the benefit of the affordable and transportable device for routine use, in particular for countries where DXA is not widely available.