Radial Head Fracture

Radial head fractures are intra articular elbow injuries and range from a nondisplaced marginal fracture to complete radial head comminution associated with elbow dislocation and longitudinal forearm instability.

The radial head contributes to:

• Valgus stability
• Axial load transmission from wrist to elbow
• Stability after medial collateral ligament injury
• Longitudinal forearm stability through interaction with the interosseous membrane and distal radioulnar joint

The radial head should therefore not be excised casually in an unstable elbow or forearm.

Modified Mason classification

Mason I

• Nondisplaced or minimally displaced
• Less than approximately 2 mm displacement
• No mechanical block to rotation

Mason II

• Displaced by more than approximately 2 mm or angulated
• Partial radial head fracture
• May cause mechanical block to pronation or supination

Mason III

• Severely comminuted fracture involving most or all of the radial head
• Frequently mechanically unreconstructible

Mason IV

• Radial head fracture associated with elbow dislocation.

Associated injury patterns

Terrible triad

• Elbow dislocation
• Radial head fracture
• Coronoid fracture

This represents a highly unstable elbow.

Essex Lopresti injury

• Radial head fracture
• Interosseous membrane disruption
• Distal radioulnar joint instability

Failure to recognise this injury before radial head excision can produce proximal radial migration, chronic wrist pain and severe longitudinal instability.

Patients have lateral elbow pain and tenderness over the radial head.

Pain is reproduced by:

• Forearm pronation
• Supination
• Elbow movement

A true mechanical block to rotation is more important than radiographic displacement alone.

Examine the entire forearm.

Specifically assess:

• Distal radioulnar joint tenderness
• Wrist pain
• Interosseous membrane tenderness
• Valgus stability
• Posterolateral elbow instability

Document posterior interosseous nerve function.

Obtain AP and lateral elbow radiographs.

A radiocapitellar view can improve visualisation.

A posterior fat pad may be the only radiographic clue to an occult nondisplaced fracture.

CT: useful for:

• Mason II fractures being considered for fixation
• Mason III injury
• Associated coronoid fracture
• Fracture dislocation
• Preoperative planning

Obtain wrist radiographs when Essex Lopresti injury is suspected.

Mason I

Treat nonoperatively.

Use a sling briefly for comfort, often only several days.

Begin early elbow and forearm motion.

Avoid immobilisation beyond approximately one week unless another injury requires it because elbow stiffness develops rapidly.

Mason II

A displaced fracture without mechanical block or instability may still be managed nonoperatively.

Operate when there is:

• Mechanical block to rotation
• Significant displacement affecting joint congruity
• Associated elbow instability
• Associated forearm instability
• Failed nonoperative care

Perform ORIF when the fracture is reconstructable.

Mason III

If the radial head can be reconstructed reliably, ORIF can be attempted.

Severe comminution involving more than approximately three major fragments is less predictably reconstructable.

In an unstable elbow or Essex Lopresti type injury, replace an unreconstructible radial head with a radial head prosthesis rather than excising it.

The implant must restore native radial length.

Overstuffing the radiocapitellar joint produces:

• Lateral elbow pain
• Loss of motion
• Capitellar wear
• Altered elbow mechanics

An implant that is too short fails to restore stability.

Radial head excision

Radial head excision has a limited role.

It may be considered in an older low demand patient with an unreconstructible isolated fracture and:

• Intact interosseous membrane
• Stable distal radioulnar joint
• Stable collateral ligaments

Do not excise the radial head when there is:

• Essex Lopresti injury
• Medial collateral ligament disruption
• Elbow instability
• Coronoid fracture with instability
• Young high demand patient where replacement is feasible

Terrible triad

Treatment generally requires:

• Radial head fixation or replacement
• Coronoid fixation when clinically significant
• Lateral collateral ligament complex repair

Assess residual medial instability after reconstruction.

Rehabilitation

Stable fractures and reconstructions require early motion.

Use a hinged brace where ligament injury requires controlled movement.

Avoid prolonged immobilisation.

Major complications include:

• Elbow stiffness
• Loss of forearm rotation
• Heterotopic ossification
• Persistent instability
• Radial head nonunion
• Post traumatic arthritis
• Proximal radial migration after inappropriate excision