Introduction and purpose: Osteogenesis imperfecta is a congenital disorder of the connective tissue, osteoporosis being the main complication with multiple fractures. Different therapy models have been tried in order to decrease bone resorption. Bisphosphanates are a group of drugs which suppress osteoclast mediated bone resorption thus reducing bone turnover. The aim of this study is to examine the improvement of bone mineralization with IV Pamidronate treatment and to determine the mobilization ability of the patients achieved during therapy with a new scoring system which was developed by these authors.

Methods: Sixteen osteogenesis imperfecta patients (9 female, 7 male) were treated with cyclic intravenous infusions of Pamidronate therapy for a period ranging from 12 to 40 months (mean 20.5±8.5 months). Pamidronate disodium was given in a dose of 20mg/m2/monthly at the beginning. The treatment regimen was changed after minor traumatic femur fractures of two patients where the bones showed peroperatively the characteristics of OSTEOPETROSIS, to cyclical therapy with 3 months intervals with the same dose. The patients’ calcium intake was evaluated regularly and was maintained with 800 mg/d oral calcium and vitamin D intake was 1000 IU at the beginning but then tapered to 500 IU according to laboratory changes. The mobilization scores of the patients were determined during treatment period with our scoring system in which scores changed from 0–40, every six months.

Results: A clinical response was shown with a reduction in fracture rate and improvement in mobilization scores. Median ambulation score was 11 and increased to 25 and to 20 in the first and the second year (p=0.001 and 0.026). Fracture rates decreased from a mean of 5.14±7.6/year before treatment to 1.4±2.3/year during treatment (p=0.018). Bone mineral density increased by, 13.6 % for the first year (p=0.29) improving from 0.219±0.103 to 0.249±0.085 g/cm2. Mean BMD increased by 34.4 % for the first 18 months from 0.219±0.1.3 to 0.294±0.07 g/cm2 (p=0.001). No adverse effects were seen with pamidronate infusions of 20/mg/m2/monthly and 3 monthly.

Conclusion: Cyclical pamidronate infusions significantly increased bone density and decreased bone fracture rate with time. According to our scoring system, IV pamidronate therapy reduces pain after initial therapy; improves the ability and the desire for sitting and walking in children. It helps them to sit and walk without any assistance.