A 78-year-old woman on long-term bisphosphonate therapy (8 years of alendronate) presents with a complete transverse fracture of the subtrochanteric region with a medial spike (beaking), lateral cortical thickening seen on prior X-rays. This pattern of fracture is best classified as:

• A Classic intertrochanteric hip fracture requiring DHS fixation
• B Atypical femoral fracture (AFF) associated with long-term bisphosphonate use ✓
• C Pathological fracture through a metastatic deposit
• D Stress fracture from early osteoporosis

Explanation

Atypical femoral fractures (AFFs) are a recognised complication of long-term bisphosphonate therapy (typically >3–5 years). The ASBMR Task Force criteria define AFFs as: (1) subtrochanteric or diaphyseal location, (2) transverse or short oblique fracture configuration, (3) minimal trauma, (4) medial spike (beak/flare), (5) lateral cortical thickening on the endosteal surface (stress reaction). The mechanism is accumulation of microdamage due to suppressed bone remodelling. Treatment is intramedullary nailing (IMN) for complete fractures; bisphosphonate holiday and teriparatide therapy for prodromal incomplete fractures.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

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Written and medically reviewed by the StethoPrep medical team.