Clinical features of atypical femur fracture

OBJECTIVES: We aim to elucidate the clinical outcomes of bisphosphonate-associated atypical femoral fracture and the clinical results depending on the bisphosphonate therapy period. METHODS: Twenty cases involving 15 patients who had been diagnosed with atypical femoral facture between 2004 and 2014 and who had been followed up for at least 12 months were retrospectively analyzed. The control group was composed of 15 typical femoral facture patients. We used plain radiography and physical examinations to determine the period of time required for fracture healing as well as complication occurrence. We investigated the bisphosphonate administration status and duration and the names of its components, bilateral fracture occurrence status, the period of time required for bone union, and reoperation or bone graft status due to nonunion. RESULTS: Revision surgery involving a bone graft was performed due to nonunion in 1 out of 15 cases. Except in one revision case, the duration of the union was 11.9 months on average in 14 cases of atypical fracture patients, and 4.3 months on average in the control group. This difference was statistically significant (p < 0.05). The bisphosphonate administration duration was positively correlated with the union period (p < 0.05). In contrast, there was no statistically significant correlation between the bisphosphonate administration duration and the incidence of bilateral atypical fractures (p > 0.05). CONCLUSIONS: Atypical femoral fractures required more time for bone union than typical ones and prolonged bisphosphonate administration led to a longer period of time required for bone union.