American Academy of Orthopedic Surgeons classification of periprosthetic hip fractures

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The American Academy of Orthopedic Surgeons classification of periprosthetic hip fractures divides the femur into three separate regions:

  • level I: proximal femur distally to the lower extent of the lesser trochanter 
  • level II: 10 cm of femur distal to level I 
  • level III: femur distal to level II 

Fractures are classified accordingly:

  • type I: fractures proximal to the intertrochanteric line; usually occur during dislocation of the hip
  • type II: vertical or spiral fractures that do not extend past lower extent of the lesser trochanter
  • type III: vertical or spiral fractures that extend past lower extent of lesser trochanter, but not beyond level II; usually at the junction of middle and distal thirds of the femoral stem
  • type IV: fractures that traverse femoral stem in level III or lie within that area
    • type IV-A: spiral fractures around the tip of the stem
    • type IV-B: simple transverse or short oblique fractures 
  • type V: severely comminuted fractures around the stem in level III 
  • type VI: fractures distal to the tip of the stem in level III

See also