Abstract
Objective: To determine the efficacy and safety of pamidronate combined with intramedullary rodding in improving bone mineralisation and reducing fracture incidence in children with osteogenesis imperfecta (O.I.).
Methods: A prospective pilot, open study was performed in which intravenous pamidronate was administered at 1.5 mg/kg bi-monthly to 12 children with O.I., over 18 – 28 months. The children were serially monitored for symptoms, anthropometric measurements, fracture incidence, biochemical assessments of calcium metabolism, bone mineral density (BMD), serum alkaline phosphatase (ALP), urinary N-telopeptides, and spine X-rays. Intra-medullary rodding of fractures were performed with when there was definite angulation of bones.
Results: The number of fractures decreased from 4 to 0.85 fractures/year during pamidronate therapy (p< 0.05). After 18 months of treatment, there was significant improvement in Areal BMD z scores of the lumbar spine from −2.38 to −1.76 (p < 0.05) and in the Volumetric BMD, which increased from 0.06 to 0.09 g/cm3 (p < 0.05). At 18 months, urine N-telopeptide levels (bone resorption marker), decreased from 439.7 to 222.3 BCE/Cr (p < 0.05), and serum ALP (bone formation marker) from 225.0 to 143.5 U/L (p < 0.05), reflecting reduced bone turnover. This may represent a net reduction in bone resorption, and provides a biochemical explanation for the increase in bone mineralisation. Height standard deviation scores were not affected, and there were no significant adverse effects.
Conclusion: 18 months cyclical pamidronate is effective in improving bone mineralisation, and reducing fracture incidence in O.I. Pamidronate therapy, which was safe, and when combined with intra-medullary rodding, can potentially improve the quality of life by improving mobility and preventing post-fracture deformities, thus offering new hope for children afflicted with OI.
The abstracts were prepared by Professor Jegan Krishnan. Correspondence should be addressed to him at the Flinders Medical Centre, Bedford Park 5047, Australia.
