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Atypical Femoral Fracture — RACP Adult Medicine MCQ

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HardEndocrinologyAtypical Femoral FractureRACP Adult Medicine

A 68-year-old woman on alendronate for 7 years presents with mid-thigh pain. X-ray shows cortical thickening of the lateral femoral diaphysis with a transverse lucent line (stress fracture). She has been compliant with bisphosphonate therapy. What is the most likely diagnosis?

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Correct answer: A — Atypical femoral fracture

Lateral femoral cortical thickening with a transverse stress fracture after prolonged bisphosphonate use (>5 years) is an atypical femoral fracture (AFF). These are associated with oversuppression of bone turnover. Bisphosphonate should be ceased. Prophylactic IM nailing may be required for incomplete fractures. Drug holiday or switch to anabolic agent should be considered.

Reference: ASBMR – 2024 – AFF Task Force Report; ANZBMS 2024