Causes / typical injury mechanism: The typical mechanism for coronoid fractures involves a fall onto an outstretched hand (FOOSH), where in addition to the presence of an axial force driving the distal humerus into the coronoid, a severe medial-to-lateral varus stress or posterior subluxation of the elbow occurs.

Coronoid fractures rarely occur in isolation and are typically associated with elbow dislocations, which is indicative of high-energy episodes associated with severe soft tissue injury, occurring during sports or heavy activities. Motor vehicle accidents may also be a cause, as well as a FOOSH at least from standing height or higher.

Classic history and presentation: Patients will present after a traumatic fall or traumatic incident such as a vehicular accident. They will be endorsing severe elbow pain with inability to move the elbow.

Prevalence: Coronoid process fractures are seen more often in younger adults due to their higher propensity for traumatic injuries and risk-taking behavior.

Pathophysiology: Commonly seen in conjunction with an elbow dislocation. A significant shearing force is necessary.

Grade / classification system:
Regan and Morrey classification system

• Type 1 – Coronoid process tip avulsion.
• Type 2 – Fracture of 50% or less of the coronoid process height. Commonly involves the anteromedial facet, which is a primary stabilizing portion to varus stress.
• Type 3 – Fracture of greater than 50% of the coronoid process height.