Application of hounsfield units of the distal fibula in evaluating bone mineral density of geriatric ankle fracture

Abstract

Objective Ankle fracture is a common type of fracture with increasing incidence in recent years. It is mainly caused by osteoporosis and has not attracted much attention. This study aimed to measure the Hounsfield units (HU) of the distal fibula by computed tomography (CT) scans, evaluate the bone mineral density (BMD) in patients with ankle fracture, and explore the correlation between BMD and ankle fracture. Methods We enrolled 74 patients with ankle fracture and divided them into osteoporosis, osteopenia, and normal groups according bone density. The examiners measured the HU of the distal fibula and we analysis calculated the best HU to distinguish group differences using the receiver operating characteristic (ROC) curve and analyzed the correlation between HU of the distal fibula and BMD, and T-score of lumbar vertebrae and the proximal femur. Results The HU of the distal fibula was significantly associated with whole parts except BMD of total lumbar, especially with BMD of L2, which had the highest correlation (r=0.555, P<0.001). The differences in HU among the groups were statistically significant. According to the ROC curve, when the HU was 157.43 HU, the area under the curve that distinguished the osteoporosis group from osteopenia group was 0.808 (P<0.001), and when the HU was 218.47 HU, the area under the curve that distinguished osteopenia from normal was 0.698 (P<0.001). Conclusions The measurement of HU of the distal fibula can accurately reflect the BMD. The HU of the distal fibula is significantly correlated with the bone mineral density and T-score of the lumbar spine and proximal femur. The cut-off value of the HU might be used effectively as an indicator of risk of osteoporosis for patients with ankle fracture.

Keywords

• ankle fracture
• hounsfield unit
• osteoporosis
• computed tomography scans
• distal fibula