Long-term radiographic follow-up of bisphosphonate-associated atypical femur fractures

Abstract

Objective: To evaluate the appearance of bisphosphonate-related femur insufficiency fractures on long-term follow-up radiographic studies and to describe the rate of fracture line obscuration and cortical beak healing over time.

Materials and methods: In this retrospective study, bisphosphonate-related femur fracture radiographs were reviewed by two radiologists for the presence of a fracture line, callus, and the characteristic cortical beak. Kaplan-Meier curves were used to analyze the time to first indication of healing. Femurs were also subdivided into those who underwent early versus late surgical fixation and those who underwent early versus late discontinuation of bisphosphonate. Clinical data including pain level and medication history were collected.

Results: Forty-seven femurs with a bisphosphonate-related femur fracture were identified in 28 women. Eighty-five percent took a bisphosphonate for greater than 5 years and 59 % for greater than 10 years. The median time to beak healing was 265 weeks and the median time to fracture line healing was 56 weeks in the 31 femurs with a baseline fracture. No statistically significant difference was identified between surgical fixation and conservative management.

Conclusions: Bisphosphonate-related fractures demonstrate notably prolonged healing time on long-term follow-up.

Keywords: Bisphosphonate; Femur; Fracture healing; Osteoporosis; Radiography.