Surgical Video: Surgical Treatment of Anteromedial Coronoid Process Fractures

I. Classification of Coronoid Process Fractures

Coronoid process fractures are classified using the Regan‑Morrey classification and the O’Driscoll classification.

In 1989, Regan and Morrey classified coronoid fractures based on the height of the fractured fragment into three types:

- Type I: fracture involving the coronoid tip

- Type II: fracture involving up to 50% or less of the coronoid height

- Type III: fracture involving more than 50% of the coronoid height

Each type is further divided into two subtypes (A and B) depending on whether the fracture is associated with elbow dislocation or not.

In 2003, O’Driscoll et al. proposed a more detailed classification based on the location, size, and mechanism of injury:

- Type I: Coronoid tip fracture, subdivided into:

 - Subtype 1: tip fragment ≤ 2 mm in height

 - Subtype 2: tip fragment > 2 mm in height

- Type II: Fracture of the anteromedial facet of the coronoid, subdivided into:

 - Subtype 1: fracture of the anteromedial rim

 - Subtype 2: fracture of the anteromedial rim and coronoid tip

 - Subtype 3: fracture of the anteromedial rim and the sublime tubercle, with or without involvement of the coronoid tip

- Type III: Fracture of the coronoid base, subdivided into:

 - Subtype 1: fracture of the coronoid base

 - Subtype 2: fracture of the coronoid base through the olecranon

The key to the O’Driscoll classification is the identification of anteromedial facet fractures of the coronoid.

II. Approach Selection for Anteromedial Coronoid Process Fractures

For anteromedial coronoid fractures, the approach between the humeral head and the ulnar head of the flexor carpi ulnaris muscle can be used. The incision is placed more posteriorly to avoid injury to the posterior branch of the medial antebrachial cutaneous nerve.

Title:Open Repair of Unstable Elbow with Anteromedial Coronoid Facet Fracture  

Author: Team of Dr. Jeffrey Stone