Classification of the AO-ASIF Group for Fractures of the Proximal Radius and Ulna

Extra-Articular Fracture

Type of Fracture

Fracture Code

fracture ulna, radius intact

avulsion of the triceps insertion from the olecranon

A1.1

metaphyseal simple

A1.2

metaphyseal multi-fragmentary

A1.3

fracture radius, ulna intact

avulsion of the bicipital tuberosity of the radius

A2.1

neck, simple

A2.2

neck, multi-fragmentary

A2.3

fractures both bones

simple in both bones

A3.1

simple in one, multi-fragmentary in other

A3.2

multi-fragmentary in both

A3.3

Articular Fracture of One Bone

Type of Fracture

Fracture Code

fracture ulna, radius intact

unifocal

B1.1

bifocal, simple

B1.2

bifocal, multifragmentary

B1.3

fracture radius, ulna intact

simple

B2.1

multi-fragmentary, without depression

B2.2

multi-fragmentary, with depression

B2.3

articular fracture one bone, extra-articular fracture other bone

ulna, articular simple

B3.1

radius, articular simple

B3.2

articular multi-fragmentary

B3.3

Articular Fracture of Both Bones

Type of Fracture

Fracture Code

both simple

olecranon and head of radius

C1.1

coronoid process and head of radius

C1.2

NA

NA

one simple and other multi-fragmentary

olecranon multi-fragmentary, radial head simple

C2.1

olecranon simple, radial head multi-fragmentary

C2.2

coronoid process simple, radial head multi-fragmentary

C2.3

both multi-fragmentary

three fragments of each bone

C3.1

ulna with more than 3 fragments

C3.2

radius, more than 3 fragments

C3.3