Bisphosphonates and atypical femoral fractures: Is the location of the fracture associated with the time of consolidation?

Introduction: Bisphosphonates are commonly prescribed to mitigate the effects of osteoporosis, a condition associated with an increased risk of fracture. However, despite their success, there has been growing concern regarding the long-term use of bisphosphonates because of the increased risk of atypical subtrochanteric fractures of the femur (AFFs). The objective of this study was to describe a cohort of patients with AFFs and evaluate the risk of evolving to nonunion, the time of consolidation associated with the location of the fracture, the time of use of the drug, and the implant involved in its treatment. Methods: This retrospective study recruited patients between June 2008 and May 2018. We identified patients with AFFs according to the task force criteria and a history of bisphosphonate use. We included all patients older than 65 years, with long-term use of bisphosphonates, AFF criteria according to the task force, and a follow-up of 12 months or longer. We studied the following variables: the time of use of bisphosphonates, localization of the fracture according to Hyodo et al., implant use, and fracture healing time, considering the presence of bone callus observed in two radiologic projections, which were measured in weeks. Results: Between June 2008 and May 2018, 72 patients met the task force criteria for AFFs. A total of 67 patients were included in this study. From this total, 37 were in the proximal region of the femur and 31 corresponded to the diaphyseal region. Univariate and multivariate analyses showed statistical significance in the time of bone healing compared with the different locations of the fracture along the femur. Conclusion: According to our study, the localization of AFFs in patients with a history of bisphosphonate use influences the duration of bone healing.