Decreased fracture incidence after 1 year of pamidronate treatment in children with spastic quadriplegic cerebral palsy

Aim: The aim of this study was to assess the rate of fracture before and after a 1-year course of intravenous pamidronate in children with spastic quadriplegic cerebral palsy (CP) who had previously experienced fractures. Method: Twenty-five children (nine males, 16 females) with quadriplegic CP in Gross Motor Function Classification System (GMFCS) level IV or V who were treated with intravenous pamidronate for approximately 1 year were identified. All participants had previously experienced at least one non-traumatic fracture. Each received 15 doses of pamidronate over a mean of 13.6 months. Post-treatment observation ranged from 1 to 10 years 6 months (mean 4y 1mo). The fracture rate before and after commencement of treatment was calculated using the person-years method. Results: The participants had experienced a total of 86 fractures before treatment began, occurring over 280.6 person-years, giving a fracture rate of 30.6% per year. During the post-treatment observation period, totalling 107.5 person-years, 8 of the 25 children experienced a total of 14 fractures. This fracture rate of 13.0% per year is a statistically significant decrease (p=0.02). Interpretation: Pamidronate treatment lowered the rate of fracture, and a 1-year course appears to provide a protective effect after treatment ends. For the majority of participants, this effect lasted 4 years or longer. However, a subset of children suffered a fracture soon after the drug was discontinued. In these children, a longer course of treatment appears to have been necessary.