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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.

2R1A Radius, extraarticular fracture

2R1A1 Avulsion of bicipital tuberosity

2R1A2 Neck, simple

2R1A3 Neck, multifragmentary

2U1A Ulna, extraarticular fracture

2U1A1 Avulsion of triceps insertion

2U1A2 Metaphyseal simple fracture

2U1A3 Metaphyseal multifragmentary fracture

2R1B Radius, partial articular fracture

2R1B1 Simple fracture

2R1B3 Fragmentary fracture

2U1B Ulna, partial articular fracture

2U1B1* Olecranon fracture

d - Simple
e - Multifragmentary

2U1B2* Coronoid fracture

n - Involving sublime facet
o - Tip (avulsion)
p - <50%
q - ≥50%

2R1C Radius, complete articular fracture

2R1C1 Simple fracture

2R1C3 Multifragmentary fracture

2U1C Ulna, complete articular fracture

2U1C3* Olecranon and coronoid fracture

d - Simple
e - Multifragmentary olecranon
s - Multifragmentary involving coronoid process

Executive Editor: Peter Trafton

Authors: Kodi Kojima, Steve Velkes

Additional credits

Proximal forearm



Elbow dislocations with associated fractures may be unstable.

Warning signs: One or more fractures involving coronoid, radial head/ neck, olecranon, or distal humerus.

Elbow dislocations should be reduced promptly with manual traction. If fractures are present, redislocation is possible. If instability is present, look for a hidden fracture.

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Evidence summary

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Additional material

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v1.0 2007-10-14