Discrimination of bone fractures by low-frequency axial transmission velocity in the radius and tibia.

Abstract

Low-frequency axial transmission velocity of the first arriving signal (VLF, 0.4 MHz) has a wavelength (8–10 mm) sufficient to probe osteoporotic changes in subcortical bone. Purpose of the present study was to evaluate VLF on retrospective fracture discrimination, using a custom-made ultrasonometer in the midshaft radius and tibia. Preliminary data for 49 non-fractured (NF; 45–87 years) and 16 fractured (F; 56–81 years) postmenopausal females were analyzed. The fractures included were caused by low or moderate trauma and mostly occurred in the forearms or lower legs. Subjects with disease or medication affecting bone metabolism were excluded. Areas under receiver operating characteristic curve were 0.76 for the radius and 0.60 for the tibia VLF. When adjusted for age and BMI, odds ratio for the radius VLF was 1.97 (95% CI: 1.11–3.48), while that for the tibia VLF was not statistically significant. In the contrary, dual-energy x-ray absorptiometry (DXA; whole-body, femoral neck, and L2–L4) was unable to differentiate between the F and NF groups. Despite the small study population, these results suggest that V𝔏𝔉 in the radius discriminates osteoporotic fractures in cases of peripheral fractures, in particular, for which DXA has a limited sensitivity.