Fractures and dislocations of the forearm
In this question we will consider proximal and mid shaft fractures, as question 6 deals with distal fractures of the forearm. So, fractures of the forearm, let's start first with the proximal fractures of the Ulna and radius, we can best classify these based on anatomy:
- Coronoid fractures
- Olecranon fractures
- Radial head fractures
- Terrible Triad injury of Elbow
After this we’ll look at fracture dislocations and elbow dislocations (Monteggia and Galeazzi).
Coronoid fractures
The coronoid is an intraarticular structure that projects from the anterior part of the ulna, articulating with the coronoid fossa of the humerus. It is important for varus stability and provides insertion for the medial ulnar collateral ligament, while functioning as an anterior buttress for the olecranon. It is the primary resistor of elbow subluxation or luxation.
Fractures may be isolated or associated with elbow dislocation (more common). The most common mechanism is that the distal humerus is driven against the coronoid in an episode of severe varus stress or posterior subluxation. Fractures of the coronoid account for 15% of all elbow injuries.
Fractures can be classified into three types:
- Type I - tip fracture
- Type II - 50% or less of height fractured
- Type III - More than 50% of the height fractured
The patient will present with elbow pain and varus or valgus deformity. Range of motion will be decreased, and it is important to do a neurovascular exam. Do AP and lateral elbow view. Treatment for stable, minimally displaced forms is brief immobilization followed by early range of motion. Displaced fractured with persistent elbow instability should be treated with ORIF.
Olecranon fractures
The olecranon, together with the coronoid process, form the greater sigmoid notch which articulates with the trochlea providing flexion-extension of the elbow joint. The triceps insert onto the posterior portion while the anconeus inserts on the lateral portion.
Fractures are generally the result of a direct blow (resulting in a comminuted fracture) or an indirect blow, falling onto outstretched upper extremity resulting in transverse or oblique fracture.
The simplest classification is the Colton classification
- Nondisplaced
- Avulsion (displaced)
- Oblique and transverse (displaced)
- Comminuted (displaced)
- Fracture dislocation