Changes in cortical and trabecular bone in algodystrophy.

We studied the pattern of bone loss in the hand of 77 patients with Colles' fracture using metacarpal morphometry, single photon absorptiometry and a radiographic scoring system. Forty-four patients had post-traumatic algodystrophy and the remainder served as controls. Both groups were immobilized in the same manner and for the same period of time and both showed loss of bone during immobilization. The loss of bone 7 weeks after fracture was significantly greater in algodystrophy than in controls both at cortical (P < 0.05) and at trabecular sites (P < 0.001). Recovery of bone occurred in the control patients by 19 weeks after fracture at cortical sites and by 31 weeks in trabecular bone. In contrast, the bone loss seen in patients with algodystrophy persisted for the 6-month duration of the follow-up, and up to 1 year in all nine patients studied for longer. These findings indicate that post-traumatic algodystrophy is associated with regional skeletal losses greater than those following uncomplicated fracture and may result in irreversible changes in the structure and thus the strength of the bony architecture.