Atypical femoral fractures in a Mexican cohort of children and adolescents with osteogenesis imperfecta. Analysis of trajectories.

INTRODUCTION

osteogenesis imperfecta (OI) is a rare inherited bone disorder resulting from defects in type I collagen synthesis or structure. It is characterized by increased bone fragility, recurrent fractures, and early-onset hearing loss. Management requires a multidisciplinary approach aimed at reducing fracture incidence, enhancing mobility, and promoting functional independence. Since 1998, bisphosphonates (BPs) have been used as compassionate therapy in OI.

OBJECTIVE

to characterize children with osteogenesis imperfecta (OI) and report the incidence of atypical femoral fractures (AFFs) in relation to the duration of zoledronic acid treatment.

MATERIAL AND

METHODS

a single group ambispective cohort study of pediatric patients diagnosed with osteogenesis imperfecta according to the Sillence criteria and treated with zoledronic acid (0.1 mg/kg/year); the retrospective period spanned from January 2008 to July 2017, while the prospective period extended from October 2017 to March 2024.

RESULTS

a total of 68 patients were included, with 24 fractures identified in 21 patients (31%). Fractures were more frequent in males (67%), adolescents (76%) and those receiving continuous treatment (76%). The duration of treatment before developing an AFF was also shorter in males (69 months) compared to females (77 months). Cox regression analysis showed that male patients with OI had a hazard ratio (HR) 3.13 (95% CI 1.18-8.26, p = 0.021) indicating a significantly higher risk of developing an AFF compared to female patients.

CONCLUSION

there may be an association between prolonged use of zoledronic acid and the occurrence of AFFs. Male and adolescents exhibited a higher risk of AFFs (HR 3.13, 95% CI 1.18-8.26) These fractures may not be limited to the femur, as other long bones could also be affected. Larger cohorts and longer follow-up periods, including control groups not exposed to zoledronic acid, are needed to establish causation.