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Revised AO/OTA classification (Jan 2018)


A revision of the AO/OTA Fracture and Dislocation Classification was published in the January 2018 issue of the Journal of Orthopaedic Trauma (Compendium and support material). This module is organized according to the 2007 version. Please read through its revised classification (below) before returning to the AO Surgery Reference.

31A1 Trochanteric region, simple pertrochanteric fracture

31A1.1* Isolated single trochanter fracture

n - Greater trochanter
o - Lesser trochanter

31A1.2 Two-part fracture

31A1.3 Lateral wall intact (>20.5 mm) fracture

31A2 Trochanteric region, multifragmentary pertrochanteric, lateral wall incompetent (≤ 20.5 mm) fracture

31A2.2 With 1 intermediate fragment

31A2.3 With 2 or more intermediate fragments

31A3 Trochanteric region, intertrochanteric (reverse obliquity) fracture

31A3.1 Simple oblique fracture

31A3.2 Simple transverse fracture

31A3.3 Wedge or multifragmentary fracture

31B1 Femoral neck, subcapital fracture

31B1.1 Valgus impacted fracture

31B1.2 Nondisplaced fracture

31B1.3 Displaced fracture

31B2 Femoral neck, transcervical fracture

31B2.1* Simple fracture

p - Pauwels 1 (<30°)
q - Pauwels 2 (30-70°)
r - Pauwels 3 (>70°)

31B2.2* Multifragmentary fracture

p - Pauwels 1 (<30°)
q - Pauwels 2 (30-70°)
r - Pauwels 3 (>70°)

31B2.3* Shear fracture

p - Pauwels 1 (<30°)
q - Pauwels 2 (30-70°)
r - Pauwels 3 (>70°)

31B3 Femoral neck, basicervical fracture

31B3 Femoral neck, basicervical fracture

31C1 Femoral head, split fracture

31C1.1 Avulsion of ligamentum teres fracture

31C1.2 Split, infrafoveal fracture

31C1.3 Split, suprafoveal fracture

31C2 Femoral head, depression fracture

31C2.1 Chondral lesion

31C2.2 Depression impaction fracture

31C2.3 Split depression fracture

Executive Editor: Joseph Schatzker, Peter Trafton

Authors: Ernst Raaymakers, Inger Schipper, Rogier Simmermacher, Chris van der Werken

Additional credits

Proximal femur



Medical assessment and care
Elderly hip fracture patients need comprehensive evaluation and management, often involving multiple specialties, because of their frequent comorbidities and complications. However, surgery should not be unnecessarily delayed.

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Evidence summary

Decision support

Additional material

Further reading

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v2.0 2010-11-14