Coronoid Process Fracture

BackgroundClassification Coronoid Fractures

 

The coronoid is the most important portion of ulno-humeral articulation

 

Reasons

1.  Provides anterior buttress

2.  Anterior capsule and brachialis attach to coronoid

2.  Anterior band of the MCL attaches to it

- distally and medially on sublime tubercle

 

Instability rises and prognosis deteriorates according to the amount of coronoid process that is fractured

 

Fracture patterns

 

Transverse

Anteromedial facet fragment

 

Mechanism

 

Most commonly associated with elbow dislocations

Anteromedial facet fractures may be caused by varus / rotational force

 

Regan and Morrey Classification

 

Coronoid Process Classification

 

Type I 

- usually stable

- shear fracture not avulsion fracture

- may rarely cause residual instability in elbow dislocation

 

Coronoid Fracture Type 1Coronoid Fracture Type 1 CT

 

Type II 

- 50% coronoid

- elbow usually unstable

- lose attachment of capsule

- ORIF screws or sutures

- any ? about stability use hinged fixator

 

Coronoid Fracture Type 2

 

Type III

- > 50% coronoid

- Uncommon

- unstable as lose capsule +/- MCL with anteromedial fragment

- ORIF with screw / sutures / anteromedial buttress plate

- again may need hinged fixator

 

Type 3 Coronoid FractureCoronoid Fracture Type 3

 

Operative Management

 

Surgical approach

 

1.  Universal posterior approach

- if performing surgery for complex dislocation

- allows medial and lateral access to joint

 

2.  Lateral approach through radial head

- if excising radial head, then replacing

 

3.  Medial approach

- isolate and protect ulna nerve  

- elevation of ulna origin of flexor pronator group anterior to FCU

- important if fracture is anteromedial

 

4.  Approach through fractured olecranon

 

Options

 

Type 1

- capsular suture repair

 

Type 2 / 3

A.  Screws (AP or PA)

B.  Pass sutures through capsule and tie over drill holes in ulna

 

Anteromedial fragment

- medial approach / buttress plate

 

Coronoid Process Buttress Plate

 

Unrepairable / unstable

- reconstruct with radial head, iliac crest, or allograft