Atypical femoral fracture

Case contributed by Dr Samir Benoudina


Building worker; carrying heavy loads daily. Fell down while carrying a 50 kg cement bag (without trauma). No medical history or medication reported. He complained from aching pain in the groin and thigh the last few weeks.

Patient Data

Age: 30 years
Gender: Male

Characteristic appearance of a complete atypical subtrochanteric fracture on the left:

  • a transverse or slightly oblique (<30°) fracture line in an area of cortical thickening (beaking)
  • medial spike.

There is also evidence of insufficiency reaction on the right subtrochanteric region with lateral cortical thickening.

Annotated image
  • oblique fracture line (yellow dotted line)
  • cortical thickening, beaking (red arrow)
  • medial spike (blue arrow)
  • Insufficiency reaction on the contralateral side (purple arrow)

Case Discussion

Atypical femoral stress fractures are often seen in patients treated with bisphosphates, but can also occur in other patients who were never put on bisphosphonates 1, as in this case.

They have distinctive radiographic characteristics 2:

  • located in the proximal third of the femoral diaphysis, inferior to the lesser trochanter
  • incomplete or complete
  • if complete: transverse or short oblique (<30°) configuration with medial spike, without comminution
  • associated focal or diffuse cortical thickening (beaking)

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