Bone loss following tibial osteotomy: A model for evaluating posttraumaticosteopenia

The reduced bone mineral density (BMD) found in patients with fractures may , in part, follow rather than precede the fracture. We studied the magnitud e and reversibility of bone loss in the 15 months following osteotomy in 21 men and 5 women with localized medial arthritis of the knee. BMD (mean +/- SD), measured using dual-energy X-ray absorptiometry, decreased by a maxim um of 35 +/- 21% in the mid-diaphysis of the affected tibia at 9 months aft er surgery (p<0.001). At 15 months, reversal of bone loss in nonfractured h ones was incomplete; the remaining deficit was 20 +/- 27% relative to basel ine (p<0.001). Maximum bone loss occurred at 9 months at the total body (5 +/- 2%), spine (15 +/- 17%) and at Ward's triangle of the proximal femur of the unoperated limb (10 +/- 17%) tall p<0.01). In summary, post-traumatic bone loss is region-specific with incomplete reversibility, at least after about 15 months. Deficits in BMD in cross-sectional studies of patients wit h fractures, held to be responsible for the bone fragility, may, in part, f ollow rather than precede the fracture.