OLECRANON FRACTURES

EPIDEMIOLOGY

Bimodal distribution, with younger individuals sustaining an olecranon fracture as a result of high-energy trauma and older individuals as a result of a simple fall.

Incidence in the adult population is 11.5 per 100,000 population per year.

Accounts for 8% to 10% of all elbow fractures.

ANATOMY

The coronoid process delineates the distal border of the greater sigmoid (semilunar) notch of the ulna, which articulates with the trochlea. This articulation allows motion only about the flexion-extension axis, thus providing intrinsic stability to the elbow joint.

The articular cartilage surface is interrupted by a transverse ridge known as the “bare area.”

The triceps tendon posteriorly envelops the articular capsule before it inserts onto the olecranon. A fracture of the olecranon with displacement represents a functional disruption of the triceps mechanism, resulting in loss of active elbow extension.

The ossification center for the olecranon appears at age 10 years and is fused by about age 16 years. There can be persistent epiphyseal plates in adults; these are usually bilateral and demonstrate familial inheritance.

The subcutaneous position of the olecranon makes it vulnerable to direct trauma.

MECHANISM OF INJURY

Two common mechanisms are seen, each resulting in a predictable fracture pattern:

Direct: A fall on the point of the elbow or direct trauma to the olecranon typically results in a comminuted olecranon fracture (less common).

Indirect: A strong, sudden eccentric contraction of the triceps upon a flexed elbow typically

results in a transverse or oblique fracture (more common).

A combination of these may produce displaced, comminuted fractures, or, in cases of extreme violence, fracture-dislocation with anterior displacement of the distal ulnar fragment and radial head.

CLINICAL EVALUATION

Patients typically present with the upper extremity supported by the contralateral hand with the elbow in relative flexion. Abrasions over the olecranon or hand may be indicative of the mechanism of injury.

Physical examination may demonstrate a palpable defect at the fracture site. An inability to extend the elbow actively against gravity indicates discontinuity of the triceps mechanism.

A careful neurosensory evaluation should be performed, because associated ulnar nerve injury is possible, especially with comminuted fractures resulting from high-energy injury.

RADIOGRAPHIC EVALUATION

Standard anteroposterior and lateral radiographs of the elbow should be obtained. A true lateral radiograph is imperative because this will demonstrate the fracture extent, the degree of comminution, the amount of articular surface involvement, and displacement of the radial head, if present.

The anteroposterior view should be evaluated to exclude associated fractures or dislocations. However, the distal humerus may obscure osseous details of the olecranon fracture.

CLASSIFICATION

Mayo Classification (Fig. 19.1)

This distinguishes three factors that have a direct influence on treatment: (1) fracture displacement,

(2) comminution, and (3) ulnohumeral stability.

Type I fractures are nondisplaced or minimally displaced and are subclassified as either noncomminuted (type 1A) or comminuted (type 1B). Treatment is nonoperative.

Type II fractures have displacement of the proximal fragment without elbow instability; these fractures require operative treatment.

• Type IIA fractures, which are noncomminuted, can be treated by tension band wire fixation.

• Type IIB fractures are comminuted and require plate fixation.

Type III fractures feature instability of the ulnohumeral joint and require surgical treatment.

Schatzker (Based on Fracture Pattern) (Fig. 19.2)

Transverse: Occurs at the apex of the sigmoid notch and represents an avulsion fracture from a sudden, violent pull of both triceps and brachialis and uncommonly from direct trauma.

Transverse-impacted: A direct force leads to comminution and depression of the articular surface.

Oblique: Results from hyperextension injury; it begins at midpoint of the sigmoid notch and runs distally.

Comminuted fractures with associated injuries: Result from direct high-energy trauma; fractures of the coronoid process may lead to instability.

Oblique-distal: Fracture extends distal to the coronoid and compromises elbow stability.

Fracture-dislocation: Usually associated with severe trauma.

Orthopaedic Trauma Association Classification of Proximal Radius/Ulna Fractures

See Fracture and Dislocation Compendium at http://ota.org/compendium/index.htm.

TREATMENT OBJECTIVES

Restoration of the articular surface

Restoration and preservation of the elbow extensor mechanism

Restoration of elbow motion and prevention of stiffness

Prevention of complications

TREATMENT

Nonoperative

Reserved for minimally displaced fractures and some displaced fractures in low-functioning older individuals.

Immobilization in a long arm cast or splint with the elbow in 45 to 90 degrees of flexion is favored by many authors, although in reliable patients, a posterior splint or orthosis with gradual initiation of range of motion after 5 to 7 days may be used.

Follow-up radiographs should be obtained within 5 to 7 days after treatment to rule out fracture displacement. Osseous union is usually not complete until 6 to 8 weeks.

In general, there is adequate fracture stability at 3 weeks to remove the cast and to allow protected range-of-motion exercises, avoiding active extension and flexion past 90 degrees.

Operative

Indications for surgery

• Disruption of extensor mechanism (any displaced fracture)

• Articular incongruity

Patient positioning

• Supine on a radiolucent table with arm over chest

  • Quick and easy setup

  • Good for patients with multiple extremity fractures

  • Requires assistant to hold arm during procedure

• Lateral

  • Allows good access to posterior elbow without need for additional assistant

• Prone

  • Allows good access to posterior elbow without need for additional assistant

Image positioning

• Image intensifier can be placed on same or opposite side of the injured extremity.

Surgical approaches

• Olecranon is subcutaneous and can be approached through a direct posterior incision.

Types of operative treatment:

• Tension band wiring or cable in combination with two parallel Kirschner wires place down the medullary canal or into the anterior cortex:

  • Tension band counteracts the tensile forces and converts them to compressive forces and is

    indicated for avulsion-type olecranon fractures (Fig. 19.3). A double- or single-knot technique can be used.

  • Placement of the wires into the anterior cortex helps to prevent wire backout and soft tissue irritation. However, wires protruding beyond the anterior cortex can cause a block to forearm rotation or irritate the anterior interosseous nerve.

  • Tension band fixation is usually reserved for concomminuted fractures proximal to the coronoid.

     

     

     

• Intramedullary (IM) fixation:

  • 6.5-mm cancellous lag screw fixation: The screw must be of sufficient length to engage the distal IM canal for adequate fixation. This may be used in conjunction with tension band wiring.

    • With IM screw techniques, beware of bowing of the ulna IM canal that may shift the fracture with screw advancement.

  • IM nail: Good results have been recently reported using a locked nail, inserted through the tip

    of the olecranon to stabilize olecranon fractures.

• Plate and screw fixation:

  • Can be used for all proximal ulna fracture types including comminuted fractures, Monteggia fractures, and olecranon fracture-dislocations. A plate should also be used for fractures that extend distal to the coronoid.

  • No mechanical difference exists between posterior or lateral placement.

  • Contoured proximal ulna plates with locking capability have gained in popularity and provide better metaphyseal fixation than conventional plates with nonlocked screws.

  • Advocates of precontoured plates with locking capability propose that these plates may

    provide better fixation in poor-quality bone.

• Excision (with repair of the triceps tendon):

  • Indicated for nonunited fractures, extensively comminuted fractures, fractures in elderly individuals with severe osteopenia and low functional requirements, and extra-articular fractures.

  • Wolfgang et al. reported that excision of as much as 50% of the olecranon is effective in treating comminuted fractures.

  • Morrey et al. demonstrated decreasing elbow stability with increasingly larger fragment

    excision and that aligning the triceps tendon with the anterior surface of the sigmoid notch increases elbow stability.

  • Excision is contraindicated in fracture-dislocations of the elbow or fractures of the radial head because excision results in compromised elbow stability.

Postoperative management: The patient should be placed in a posterior elbow splint. With a

stable repair, one should initiate early range-of-motion exercises.

COMPLICATIONS

Symptomatic hardware may occur in up to 80% of patients.

• Hardware removal may be required in 34% to 66% of patients.

• May be lower incidence with use of precontoured locked plates and IM nails.

Hardware failure occurs in 1% to 5%.

Infection occurs in 0% to 6%.

Pin migration occurs in 15%.

Ulnar neuritis occurs in 2% to 12%.

Heterotopic ossification occurs in 2% to 13%.

Nonunion occurs in 5%.

Decreased range of elbow motion: This may complicate up to 50% of cases, particularly loss of elbow extension, although most patients note little if any functional limitation.