Atypical Femoral Fracture in a Patient without Bisphosphonate or Denosumab Exposure-A Case Report

Abstract

Introduction: Atypical femoral fractures (AFF) are associated with the use of bisphosphonates (BPs) or denosumab. However, few cases that meet the characteristics of these fractures, as established by the American Society of Bone and Mineral Research, have occurred in patients who have never used antiresorptive drugs.

Case report: We report a case of AFF in a 67-year-old woman who had never used antiresorptive medications. The history and comorbidities of the patient, the characteristics of the fracture, and the subsequent treatment are presented.

Conclusion: AFFs may occur even in patients who have never been exposed to BPs or denosumab. The absence of antiresorptive osteoporosis therapy and the lack of radiographic focal periosteal reaction in the lateral femoral cortex, as in our case, can make it difficult to detect and prevent the disorder. Prolonged use of proton pump inhibitors and Vitamin D deficiency-related osteomalacia may contribute to the occurrence of these fractures. Further studies are required to accurately understand all inciting factors contributing to the development of AFFs.

Keywords: Atypical femoral fractures; antiresorptive drugs; bisphosphonates; denosumab; subtrochanteric fractures.

Figure 1

Pelvis radiograph, 2 months before the fracture, showing subtle minimal endosteal thickening in the lateral cortex of the right subtrochanteric femur (arrow) without localized periosteal thickening.

Figure 2

Plain radiograph of the right femur (upon arrival of the patient), showing progression to complete transverse atypical femoral fracture leading medially to a medial spike (arrow).

Figure 3

Coronal reformatted computed tomography image of the right femur (upon arrival of the patient), showing complete atypical femoral fracture associated with medial spike.

Figure 4

Plain radiograph, 2 days after surgery, showing intramedullary nail fixation of the right femur.

Figure 5

Sagittal reformatted computed tomography image of the right femur, 6 months after intramedullary nailing, showing delayed union of the atypical femoral fracture.

Figure 6

(a and b) Radiographs of the pelvis (a) and the right hip – lateral view (b), 13 months after the initial operation, showing atypical femoral fracture healing.