Association of low-energy femoral shaft fractures and bisphosphonate use.

The purpose of this study was to elaborate on the association between the use of bisphosphonates and low-energy femoral shaft fractures. A retrospective review was performed between January 2000 and January 2010 to identify patients older than 65 years who sustained femoral shaft diaphyseal fractures (Orthopaedic Trauma Association classification 32 A [extra-articular], B [partial articular/unicondylar], or C [complete articular/bicondylar]) using ICD-9 code 821.01. After exclusion criteria were applied, 77 patients remained for analysis. A total of 66 patients had no history of bisphosphonate therapy, and 11 patients had received bisphosphonate therapy for >2 years prior to admission. All 11 patients in the bisphosphonate group had sustained a low-energy fall from a standing height or lower. In 9 of 11 (82%) patients in the bisphosphonate group, radiographs resembled transverse shaft fractures with lateral cortical beaking that have been observed in patients on chronic bisphosphonate therapy.Our series echoes the findings of other authors, who found that bisphosphonate use is associated with lateral cortical beaking and low-energy, transverse fractures of the femoral shaft. Further research is needed to determine if specific medications and length of treatment are important risk factors.