Bisphosphonate Treatment and the Characteristics of Femoral Fractures in Children With Osteogenesis Imperfecta.

Context: The short-term benefits of bisphosphonates (BPs) are evident in the treatment of children with osteogenesis imperfecta (OI), but some concerns related to long-term effects remain. Objective: To elucidate the effect of BPs on characteristics of femoral fractures in children with OI. Design and Setting: Retrospective cohort study at a university hospital. Patients and Main Outcome Measure: The study included 93 patients with OI. We recorded fracture histories and analyzed all femoral fractures for location and fracture type using radiographs obtained at fracture diagnosis. Effects of BPs were evaluated by comparing fracture characteristics in three groups: patients (1) naive to BPs, (2) receiving ongoing BP treatment, and (3) whose treatment was discontinued. Results: In total, 127 femoral fractures occurred in 24 patients. Of the fractures, 63 (50%) occurred in patients naive to BPs, 44 (35%) during BP treatment, and 20 (16%) after treatment discontinuation. Mid or distal shaft fractures were most common (41%), followed by subtrochanteric (33%) and distal (20%) fractures. Almost all fractures were transverse (65%) or oblique (28%). The pattern of femoral fractures was similar in all three BP treatment groups (P = 0.78 for location; P = 0.35 for fracture type) and was not related to cumulative BP dose. Instead, OI type correlated with fracture characteristics, and distal location and transverse configuration were more common in the more severe types III and IV compared with type I OI. Conclusion: Characteristics of femoral fractures in children with OI are affected by OI type but not by BP exposure.