Case Report - Short-term Bisphosphonate Use Associated Stress Fractures

Abstract

Introduction: Long-term bisphosphonate use has been linked to an increased risk of pathological neck of femur fractures.

Case report: We write concerning a patient who presented with the left hip pain following a low impact fall, which was diagnosed as a pathological left neck of femur fracture. This was a subtrochanteric stress fracture most frequently seen in patients who take bisphosphonate medications. A key point of difference in our patient is the length of time of bisphosphonate use. A further interesting point was the method of imaging used to diagnose this fracture whereby plain radiographs and computerized tomography imaging both did not show any acute fracture whereas only a magnetic resonance imaging (MRI) hip demonstrated this fracture. Surgical insertion of a prophylactic intramedullary nail was done to stabilize the fracture and reduce the risk of progression to a complete fracture.

Conclusion: This case brings up multiple key points not reviewed previously such as the fact a fracture developed only 1 month after bisphosphonate use rather than months or years. These points suggest that there should be a low threshold for investigation (including MRI scanning) into potential pathological fractures and that bisphosphonate use should be a red flag to initiate these investigations regardless of length of use.

Keywords: Atypical stress fractures; bisphosphonate use; magnetic resonance imaging.

Figure 1

Blood tests result on admission.

Figure 2

Plain radiographs of pelvis and left femur.

Figure 3

Coronal images of CT hip.

Figure 4

Coronal image of MRI hip showing left lateral femur fracture.

Figure 5

X-ray image of left femur following insertion of IM nail.