My Orthopedic Surgery

"21-Radius/Ulna Proximal,fracture classification and diagnosis, AO North America -Comprehensive Classification of Fractures of Long Bones"

Fractures of the coronoid rarely occur in isolation. They usually occur in combination with a radial head fracture, a dislocation of the elbow, or both (terrible triad of the elbow). Large coronoid fractures often are associated with persistent elbow instability even after reduction of the dislocation; recently the increasing trend has been toward fixation of these injuries in order to restore stability and initiate an early range of motion program.
Synonyms and related keywords: fracture dislocation of the elbow, elbow fracture, broken arm, broken elbow, Monteggia fractures, elbow fracture dislocation, radial head fracture, terrible triad of the elbow
Tejwani & Thacker 2006

Classification and treatment:
- type I: fracture of the tip of the coronoid process;
- type II: fracture or comminution constitutes about half of coronoid;
- treated with early motion if no instability is present;
- type III: fracture or comminution constitutes more than half of coronoid;
- almost always involves dislocation (see below);
- fractures near the coronoid base are associated with increased instability due to loss of the stabilizing function of coronoid itself as well as loss of the insertion of the anterior band of the MCL and anterior joint capsule
Wheeless' Textbook of Orthopaedics