Bone Abstracts

The authors present own group of 4213 patients treated with bisphosphonates (BFs) and development of atypical fractures (AF) after 2 years follow up. At the beginning 2147 patients were treated with alendronate and 2066 with ibandronate. Totally 15 fractures were found in the alendronate group (two in adult patients with osteogenesis imperfecta) and 14 in the ibandronate group (one in adult patients with osteogenesis imperfecta). All radiographic examinations were subjected to the retrospective analysis of fracture type including fractures of femur and humerus.

Results: In the alendronate group four pertrochanteric, six diaphysis of femur, two subtrochanteric and two periprothetic fractures were identified. No fracture of femur was found in this group. Based on radiography analysis after trauma or surgery three fractures met the criteria for an atypical fracture in the alendronate group. In the ibandronate group four pertrochanteric, two subtrochanteric, five fractures of femur diaphysis and two periprosthetic fractures in patients with endoprothesis were identified. There was no fracture of femur found and only 1 fracture met the criteria for AF in the ibandronate group.

After 2 years most of the patients were activelly treated, the part stopped or took a drug holiday. 2460 patients on alendronate (2166 actively treated, 294 newly initiated) and 2169 on ibandronate (1911 actively treated, 258 newly initiated) were checked for atypical fracture development with the same methodology like 2 years ago. There was only one patient with a new atypical fracture of femur identified.

The authors discuss identification of risk factors for future AF development at the beginning of therapy, especially proximal femur curvature. Atypical fractures are usually very rare when diagnosis, indication of therapy and carefull follow up is done properly.