Association of Low-energy Femoral Shaft Fractures and Bisphosphonate Use

Abstract

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.

Prophylactic Intramedullary Fixation for Bisphosphonate-related Subtrochanteric Stress Fracture

“…Atypical femur fractures associated with bisphosphonate use have been defined by the following radiographic parameters: simple transverse or short oblique fracture in areas of thickened cortices with lateral unicortical beaking. 7,[9][10][11][12][13]15,16,18 Population-based studies have attempted to demonstrate that the incidence of subtrochanteric and diaphyseal femur fractures are equivalent in patients taking bisphosphonates and those who are not. 15,17 These studies have failed to recognize that atypical femur fractures due to bisphosphonate use are a specific subset of subtrochanteric and diaphyseal fractures identified by radiographic examination rather than raw incidence of fracture location.…”

“…Other authors have reported the incidence of these atypical fractures to account for 69% to 100% of fractures. 9,10,16 The true incidence of atypical fractures in patients on bisphosphonate therapy is unknown due to the large number of patients taking this class of medications compared with the relative few who sustain these fractures.…”

“…This radiographic finding has been documented in multiple reports to be associated with chronic bisphosphonate use. 13,15,16 The lateral cortical thickening is presumed to be a result of the inability of osteoclasts to remodel bone secondary to inhibition by bisphosphonates. 16 Although cortical thickening in the subtrochanteric femur could be indicative of a stress fracture, this pattern in association with bisphosphonate use is nearly pathognomonic for a bisphosphonate-related stress fracture.…”

Treatment and Prognosis of Femoral Insufficiency Fracture Associated with Prolonged Bisphosphonate Use

“…골다골증 치료제 중 비스포스포네이트 제제는 지난 20년 동안 골다공증의 치료에 성공적인 역할을 맡아왔으며 치료의 표준으로 자리 잡아가고 있다 5) . 비스포스포네이트 제제는 파골세포의 작 용을 억제하고 세포사멸을 증진시켜 골밀도를 증가시키는 작용을 한다 17) .…”