Partial articular olecranon fractures are classified as 2U1B1 fractures.
This fracture has the following qualifiers:
• d – Simple (illustrated)
• e – Multifragmentary
Pure olecranon fractures usually represent a disruption of the extensor (triceps) mechanism, with a bending moment over the distal end of the humerus. More direct forces generate fragmentation and impaction of the central portion of the articular surface of the olecranon and often more complex fragmentation involving the coronoid.
Sometimes, the humerus is driven through the olecranon with anterior dislocation of the forearm. These fractures are covered in the section on transolecranon fracture-dislocations.