Association between bone mineral density and ulnar styloid fracture in older Japanese adults with low-energy distal radius fracture.

Abstract

The pathogenesis of ulnar styloid fracture (USF), which often occurs with distal radius fracture (DRF), is unclear. This study aimed to investigate whether USF concomitant with low-energy DRF was associated with the bone mineral status and the degree of radiographically observed pretreatment radius displacement in Japanese adults above 50years of age. The study subjects were 45 (44 female, 1 male) consecutive patients aged > 50years with DRF caused by falls from June 2015 to May 2016. Fractures due to high-energy injuries were excluded. Patients were divided into two groups according to the presence or absence of USF. Radius displacement was assessed on anteroposterior and lateral radiographs by measuring ulnar variance, radial inclination, and volar tilt at initial examination before manual reduction of the bone. Bone mineral density (BMD) of the lumbar spine, femoral neck, and distal radius was also measured by dual-energy X-ray absorptiometry within 1week of injury. Significant differences in the BMD values of femoral neck, ulnar variance, radial inclination, and volar tilt were found between patients with USF and those without USF (all comparisons, p < 0.05). Logistic regression analysis of all subject data identified that volar tilt was significantly associated with the presence of USF (p = 0.048). The presence of USF in low-energy DRF correlates with the decreased BMD of femoral neck and severe displacement of radius in elderly patients. These findings are helpful for the treatment of osteoporosis to prevent subsequent fragility fracture.