Prevention of postoperative osteopenia using IV pamidronate: a pilot study.

BACKGROUND

Postoperative bone mineral density (BMD) loss, especially after cast immobilization and/or non-weight-bearing, is a well-known phenomenon in children that can cause fracture. Children with marginal bone density are at greatest risk. This prospective randomized control trial compared the effect of single-dose intravenous (IV) pamidronate versus placebo to prevent postoperative BMD loss.

METHODS

Children between the ages of 4 and 18 were included in the study; inclusion criteria included a predisposition to low bone density and hip or lower extremity surgery that would require cast immobilization or non-weight-bearing for at least 4 weeks. Dual-energy x-ray absorptiometry (DXA) scans of the lumbar spine and bilateral distal femora were performed preoperatively and at least 4 weeks postoperatively. Subjects were randomized to receive either a single, low dose of IV pamidronate (1 mg/kg) or placebo, given during the immediate postoperative period. Changes in the BMD were compared using the Mann-Whitney test for significance in the lumbar spine. A multivariate general linear model was used to compare the effect of surgery, DXA region, and treatment on BMD.

RESULTS

A total of 24 subjects were included in the study, and 20 completed the protocol. Pamidronate-treated subjects showed a statistically significant difference with a median gain in BMD of 0.029 gm/cm in the lumbar spine compared with the control group, which showed a median loss of 0.025 gm/cm. Treatment did not have a statistically significant effect on BMD loss in the distal femur but trended toward decreased BMD loss (treatment=0.0331 gm/cm, control=0.0416 gm/cm). There were no complications or adverse reactions.

CONCLUSIONS

This small pilot study shows that single-dose postoperative pamidronate mitigated postoperative BMD loss in at-risk children, which may in turn decrease postoperative fracture risk. Further investigation into the use of IV pamidronate in postoperative patients is warranted.

LEVEL OF EVIDENCE: Level 1 double-blinded randomized control trial.