Femoral head density on CT scans of patients following hip fracture fixation by expandable proximal peg or dynamic screw

Computed tomography (CT) is currently considered to be an accurate method for evaluating bone density. We evaluated the CT measurements of bone density using the Hounsfield units (HUs) in 23 patients who had been operated in the past for an extra-capsular hip fracture. Twelve patients were treated with a dynamic hip screw and 11 with a proximal femoral expandable hip nail. All the CTs had been performed for non-orthopedic purposes. Bone density with a region of interest (ROI) could be assessed for both hips. We compared the bone density between the operated versus the non-operated sides as well as between the two surgical groups.Bone density was higher in the hip peg (the femoral component of the expandable nail) side 262.5 (range, 169–351) HU, compared to the opposite non-operated side and to the hip screw group 194 (range, 99–283) HU. The hip screw side had decreased bone density compared to the opposite non-operated side. We were able to define a density index and a difference index: both were higher in the hip peg group. These findings persisted over time. It would be interesting to speculate that increased bone density around an expandable peg provides better fracture stabilization and probably faster healing than a dynamic hip screw.