Objective: Bisphosphonates (BPs) are widely used in treatment of pediatric patients with osteogenesis imperfecta (OI) and their beneficial effect on bone density and fracture rates has been well reported. Atypical femoral fracture is a potential complication of bisphosphonates, usually occurring after several years of BP treatment in postmenopausal women. Some evidence suggests increased proportion of subtrochanteric femoral fractures in children with OI after prolonged use of bisphosphonates. The purpose of the present study was to assess whether BP treatment modifies the characteristics of femoral fractures in pediatric patients with OI.
Methods: This retrospective study included pediatric OI patients born between 1990 and 2012 and followed at Childrens Hospital, Helsinki University Hospital, Finland. Altogether 93 patients were identified; all their femoral fractures that occurred before 31.12.2012 were analyzed using medical records. Radiographs were re-evaluated and the fractures were categorized by position and morphology and compared with the status of BP treatment.
Results: In total 168 femoral fractures had occurred in 32 patients (16 had OI type I, 8 type III, and 8 type IV); hospital records for 145 fractures were available. Of the fractures 46 had occurred during BP treatment, 20 during drug holiday and 79 in a patient naïve to BPs. At the time of fracture the mean age of patients was 6.7 years, range from week to 18.5 years and the mean duration of the BP treatment (if present) was 1.1 years, range from 1 day to 3.15 years. The level of fracture was proximal in 5.5%, subtrochanteric in 26.2%, mid or distal shaft in 49.7% and distal in 18.6% of the cases. The morphology was transverse in 61.8%, oblique in 31.3%, and other (for example spiral or comminuted) in 6.9%. There were no correlation with former or present bisphosphonate treatment and fracture position or morphology.
Conclusion: Based on our findings BP treatment does not change the characteristics of femoral fractures in children with OI.
Disclosure: The authors declared no competing interests.
27 - 30 Jun 2015