Olecranon Fracture

An olecranon fracture is an intra articular fracture of the proximal ulna involving the trochlear notch and insertion of the triceps mechanism.

The olecranon performs three major functions:

• Forms the proximal trochlear articulation
• Provides a posterior buttress preventing anterior translation of the ulna
• Serves as the insertion of the triceps tendon

Treatment therefore depends on both articular congruity and integrity of the extensor mechanism.

Mechanisms include:

• Direct impact onto the posterior elbow, commonly producing comminution
• Indirect injury from sudden triceps contraction, commonly producing a transverse fracture
• High energy fracture dislocation

Mayo classification

The Mayo classification is based on displacement, comminution and ulnohumeral stability.

Type I: Nondisplaced

Displacement below approximately 2 to 3 mm and a stable elbow.

IA

Nondisplaced, noncomminuted.

IB

Nondisplaced, comminuted.

Type II: Displaced but stable

The fracture is displaced, but the ulnohumeral articulation remains stable.

IIA

Displaced, noncomminuted.

IIB

Displaced and comminuted.

Type III: Displaced and unstable

The fracture is associated with ulnohumeral instability or fracture dislocation.

IIIA

Unstable, noncomminuted.

IIIB

Unstable and comminuted.

Mayo IIA is the classical simple displaced transverse fracture suitable for compression or tension band principles, whereas IIB and III injuries generally require plate fixation.

Associated injuries

Look for:

• Radial head fracture
• Coronoid fracture
• Monteggia type injury
• Elbow dislocation
• Collateral ligament injury

A transolecranon fracture dislocation is different from a Monteggia injury. The proximal radioulnar relationship remains intact, but the forearm translates through the comminuted trochlear notch.

Patients present with posterior elbow pain, swelling and haemarthrosis.

A palpable gap may be present.

Assess active elbow extension.

Loss of active extension suggests disruption of the extensor mechanism, although pain can make examination unreliable.

Inspect carefully for an open wound because the olecranon has minimal posterior soft tissue coverage.

Document:

• Ulnar nerve function
• Median nerve function
• Radial nerve function
• Radial and ulnar pulses

AP and lateral elbow radiographs: usually establish the diagnosis and degree of displacement.

CT is useful for:

• Major comminution
• Fracture dislocation
• Coronoid involvement
• Complex proximal ulna reconstruction

Nonoperative treatment

Appropriate for:

• Mayo type I fractures
• Intact extensor mechanism
• Stable elbow

Selected frail, low demand older patients with displaced but stable fractures may also be treated nonoperatively when the morbidity of fixation outweighs the benefit. Functional outcomes can remain acceptable despite a fibrous nonunion.

Use brief posterior splint immobilisation followed by early range of motion.

Avoid prolonged immobilisation because the elbow develops stiffness rapidly.

Operative indications

Operate for:

• Displaced fracture in an active patient
• Loss of active extension
• Articular incongruity
• Unstable fracture
• Open fracture
• Fracture dislocation
• Failure of nonoperative treatment

Simple transverse fracture

Mayo IIA fractures can be treated with:

• Tension band fixation
• Intramedullary screw with tension band augmentation
• Plate fixation

Tension band constructs rely on an intact anterior cortex and a simple fracture that can be compressed.

Do not use tension band wiring for severe comminution, distal extension or unstable fracture dislocation.

Classic K wire tension bands are effective but frequently produce symptomatic posterior metalwork. Plate fixation has lower rates of hardware related reoperation in several comparative series.

Comminuted fracture

Mayo IIB and most type III fractures require precontoured proximal ulna plate fixation.

Reconstruct:

• Trochlear notch
• Olecranon length
• Proximal ulna alignment
• Coronoid where involved

Avoid narrowing or distortion of the trochlear notch.

Small depressed articular fragments may require elevation and support.

Fragment excision

Excision of the proximal fragment with triceps advancement has a limited role.

Consider only when:

• Elderly low demand patient
• Severe osteoporotic comminution cannot be reconstructed
• Less than approximately 50% of the olecranon articular surface would be removed
• Elbow remains stable

Avoid this strategy in young or active patients and in fracture dislocations because removal reduces posterior elbow stability.

Postoperative care

Stable fixation should permit early elbow motion.

Protect active resisted extension initially while the fracture heals.

Major complications include:

• Symptomatic hardware
• Elbow stiffness
• Loss of extension
• Ulnar nerve symptoms
• Post traumatic arthritis
• Infection
• Nonunion
• Fixation failure