Summary: The authors studied the density of the proximal fragments of 16 scaphoid fractures using plain radiographs and dual energy X-ray absorptiometry (DEXA). All fractures were treated with cast immobilization. At 6 to 12 weeks post injury, median reductions of 9% and 10% were observed in bone mineral density in the proximal scaphoid fragment and distal radius, respectively. A greater median reduction in bone mineral density (27%) was observed in the distal scaphoid fracture fragment. The DEXA scan changes did not correlate with the visualized radiographic density of the proximal pole. The authors hypothesized that the increase in radiographic density of the proximal scaphoid fragment might be due to an increase in bone loss from the distal fragment rather than impaired blood flow to the proximal fragment.
Increased radiographic density of the proximal pole of an acute scaphoid has been historically attributed to reduced proximal fragment blood flow. However, intraoperative observations of bleeding from the proximal pole (Green, JH, 1985), and MRI studies of scaphoid vascularity (Downing et al, JHS, 2002; Sakuma et al, JHS, 1995) have demonstrated no clear relationship between decreased blood flow and increased proximal fragment radiopacity. The findings from the present study suggest a relative increase in radiographic density of the proximal fragment from an increase in blood flow to the distal fragment and focal osteoporosis.
Scaphoid, Fracture, Density, Proximal, Pole, Vascularity
Journal of Hand Surgery