Fig. 7
From: Stress fracture of the pelvis and lower limbs including atypical femoral fractures—a review
An elderly female on long-term bisphosphonates for osteoporosis had suffered a sudden fracture of the right femoral shaft after a period of niggling right thigh pain. This had been treated with an intramedullary nail. Then similar pain developed on the left side. A radiograph (a) shows subtle cortical thickening of the lateral aspect of the femoral shaft (see arrow). Bone scintigraphy (b) and MRI performed 1 month later (coronal T1w c, coronal STIR d) show mild uptake of the left femoral shaft and a minor bone reaction of the left lateral femoral shaft (see arrows). Marked uptake of the right femoral shaft on the bone scan is due to previous fracture; an intramedullary nail is in situ resulting in increased uptake in the proximal femur (see arrowhead). This is a so-called atypical femoral fracture. An AP radiograph of the hips performed for right hip/groin pain in another elderly female patient shows a more advanced case with a fracture through the lateral subtrochanteric femoral shaft cortex with a minor bone reaction; only a small bony spike is seen (e, arrow). Atypical femoral shaft fractures often affect elderly patients on long-term bisphosphonates. The lateral femoral cortex is affected first, bone reaction is minor, and the fracture lines are fairly horizontal