Analysis of fracture healing process by HR-pQCT in patients with distal radius fracture

High-resolution peripheral quantitative computed tomography (HR-pQCT) has enabled us to observe the changes in bone microarchitecture over time in vivo. In this study, the process of fracture healing was analyzed using HR-pQCT in patients with distal radius fracture who underwent osteosynthesis.

A total of 10 fracture sites identified from four patients with a distal radius fracture who underwent internal fixation with a volar locking plate (mean age 68.8 years, all women) were investigated. HR-pQCT was performed within a week (baseline) 4, 12, and 24 weeks after fracture. Rectangular region of interest (ROI) was established in the fracture site, inner callus, and external callus area, and the changes in bone mineral density (BMD) in each region were analyzed.

From baseline to 24 weeks post-fracture, the BMD changed from 105.5 (95% CI 98.6-113) to 428.0 (331-554) mgHA/ccm at the fracture site, from 111.0 (104-119) to 375.3 (290-486) mgHA/ccm at the inner callus area, and from 98.5 (91.6-106) to 171.6 (132-222) mgHA/ccm at the external callus area. The BMD increased at the fracture site and inner callus area, but increased only slightly at the external callus area. At 24 weeks post-fracture, the BMD at the fracture site and inner callus area was significantly higher than the external callus area.

In the healing process of postoperative distal radius fractures, increased BMD at the inner surface of the fracture site was confirmed in all fractures. Bone formation on the endosteal side may be a necessary condition for bone union of distal radius fractures.