Olecranon fractures

Invalid License

License is not configured.

Introduction

Olecranon fractures exhibit a bimodal distribution: low-energy injuries in the older age group and higher-energy mechanisms in the younger population. The mechanism of injury often dictates the fracture pattern. An indirect injury results from a fall onto an outstretched hand. As the hand touches the ground, a forceful contraction of the triceps muscle pulls a portion of the olecranon off in an avulsion or oblique fashion. This is in contrast to a direct mechanism in which a force is applied directly to the olecranon, leading to a more comminuted fracture pattern. Less commonly, the olecranon may fracture when the elbow is hyperextended, as the bone is impacted against the olecranon fossa of the distal humerus.

Anatomy

The olecranon is the region of the proximal ulna that extends from the tip of the ulna to the coronoid process.

The ossification center of the olecranon appears around age 10 and fuses at about age 16.

The olecranon position lends itself to fracture, as it is a subcutaneous bony prominence. It represents the posterior aspect of the elbow joint.

The semilunar notch is defined as the area between the tip of the olecranon and the tip of the coronoid process; it hold the trochlea of the distal humerus. The trochlea has a groove in its center that coincides with an edge in the center of the semilunar notch (aka, greater sigmoid notch) of the ulna.

The articulation between the trochlea and the anteromedial facet of the coronoid, along with the radiocapitellar joint, account for the intrinsic osseous stability of the elbow joint. There is a transverse ridge on the semilunar notch known as the bare area, which is devoid of articular cartilage.

The posterior process of the olecranon prevents posterior translation of the humerus and the coronoid process prevents anterior translation.

Figure 1a.

On the olecranon, the triceps tendon inserts and surrounds the joint capsule. In similar fashion to the patella, an olecranon fracture often corresponds to a functional disruption of the extensor mechanism of the elbow joint.

Clinical Presentation

The typical presentation of a patient with an olecranon fracture is elbow pain, swelling, and an inability to extend the elbow against gravity. Diagnosis of any upper extremity injury begins with a thorough physical examination of the entire extremity, including observation, palpation, and a complete neurovascular exam. A palpable defect can be appreciated if there is significant displacement of the fracture. It is extremely important to closely examine the skin for any openings given the subcutaneous location of the ulna.

Due to proximity to the fracture site and zone of injury, pay close attention to the ulnar nerve during neurovascular exam; it is affected approximately 10% of the time. The anterior interosseus nerve injury may be involved in Monteggia injuries

In low-energy falls, especially in older patients, the mechanism of injury should be thoroughly evaluated to ensure that there is no underlying medical cause (eg, syncope). Associated injuries such as distal radius fractures, cervical spine injuries, and hip fractures should also be considered in this population

Post-manipulation radiographs or a CT scan may provide additional information for fracture-dislocations or when radial head or coronoid process fractures are suspected.

Imaging and Diagnostic Studies

Standard anterioposterior and lateral radiographs are adequate for routine diagnosis and surgical planning. It is essential to obtain a true lateral radiograph of the elbow to evaluate the extent of the fracture, degree of displacement and comminution, and the degree of articular surface involvement. A CT scan is recommended if the fracture is comminuted or if there is concerns about associated radial head or coronoid process fractures.

Classification

There are several classifications systems used for olecranon, proximal ulna, and radial fractures. No one classification is universally used.

AO Classification

Type A: Extra-articualar fractures at the metadiaphysis level
Type B: Intra-articular fractures of either the radius or ulna
Type C: Complex fractures of both the proximal radius and ulna

Schatzker Classification

Transverse fracture through the deepest point of the trochlear notch, usually resulting from sudden pull of the tricep
Complex transverse fracture with comminution or central, articular impaction from a direct force
Oblique fracture usually from hyperextension
Comminuted fractures with associated fracture of the coronoid process
Oblique fracture distal to the midpoint of trochlear notch (tension band fixation is inadequate)
Olecranon fracture with associated radial head fracture and possibly medial collateral ligament injury

Mayo classification

Type I: Non-displaced fractures. The fracture may be either non-comminuted (Type IA) or comminuted (Type IB).
Type II: Displaced, stable fractures. The proximal fracture fragment is displaced more than 3 mm, but the collateral ligaments are intact and there is no elbow instability. The fracture may be either non-comminuted (Type IIA) or comminuted (Type IIB).
Type III: Displaced, unstable fractures. The proximal fracture fragment is displaced and the forearm is unstable in relation to the humerus. This is a fracture-dislocation. It also may be either non-comminuted (Type IIIA) or comminuted (Type IIIB).

Treatment

Non-operative treatment

Non-displaced fractures in which the extensor mechanism is intact may be treated without surgery.
The elbow should be immobilized in 30 degrees of flexion for at least 6 weeks. However, some authors recommend gradual, protected range of motion to begin at 7-21 days, avoiding flexion past 90 degrees.¹
Repeat radiographs should be obtained at 1 week to assess for displacement of the fracture.
It is rare to treat an olecranon fracture non-operatively because of the length of time needed for immobilization and the risk of stiffness.

Operative treatment

Surgical Planning

The patient can be positioned either supine with the arm across the chest or lateral decubitus/prone with the arm draped over a padded support.
Either a sterile or non-sterile tourniquet applied at the upper arm can be used.
General or regional anesthesia (eg, axillary block) can be utilized.
A midline posterior skin incision is utilized, incorporating open wounds if present. A curvilinear approach that does not pass directly over the olecranon can be used, but it may cross more cutaneous nerves.
The ulnar nerve usually does not need to be isolated.

Surgical Techniques

Tension band wiring (Figure 2)

This technique is used for simple fractures at the level of the transverse groove.
Failure to recognize distal extension or more complex injury will lead to fixation failure.
After inspection to rule out more extensive comminution and after reduction, two parallel 0.062- or 0.045-inch Kirschner wires are passed through the fracture site and through the anterior cortex distal to coronoid process.
One or two holes are drilled transversely across the ulna distal to fracture site.
One 18-gauge or two 22-gauge stainless steel wires are passed through the holes and placed in a figure-of-eight configuration. The proximal part of the wire is passed through the insertion of the tricep. The wires are tensioned with two loops on both sides of the figure-of-eight configuration.
This technique converts tension forces into compression forces at the fracture site.

Intramedullary screw technique

This technique can be used in lieu of tension band wiring for simple fractures.
A large 6.5-mm cancellous screw is placed down the shaft of the ulna to grab the distal cortex.
Complications include malreduction and distal ulna fracture.
A tension band can supplement screw fixation.

Plate and screw fixation

This technique is used for comminuted fractures, Monteggia fractures and olecranon fracture-dislocations (discussed in the next section).
Dynamic compression plates are used. One-third tubular plates are not adequate for fixation.
Plates can be placed dorsally, medially, or laterally.
The plate should contour around the proximal ulna to increase the number of screws that can be placed proximally.
The triceps insertion can be incised longitudinally to place the plate directly on bone.
Anatomic restoration of the coronoid and olecranon process is critical and the remaining comminution can be bridged.

Excision and tricep advancement

This technique is rarely indicated as primary treatment.
It may be used in significantly comminuted, osteopenic bone for infirm, older patients with low functional demands.
This technique is contraindicated with collateral ligament, radial head, or coronoid process injury.
After excision of the fragments, the triceps is attached with large grasping sutures through drill holes just below the articular margin.
Excision of larger pieces has greater potential for elbow instability.

Postoperative Management

Active range of motion should be initiated the day after surgery.
Resistive exercises should be delayed until early healing is seen at 6-8 weeks.
Tenuous fixation or excision and triceps advancement should be immobilized for 4-6 weeks before exercises are started.

Outcome

Olecranon fractures heal well in most instances. Functional outcome is dependant on fracture severity, length of immobilization, and host factors.

Complications

1. Hardware Failure

This complication occurs in up to 5% of patients.
Tension bands will fail if they ar eused for comminuted or complex fractures.
Plates may fail if they are not properly contoured or placed either medially or laterally.

2. Hardware prominence

Symptoms from hardware prominence have been reported as high as 80%.
Hardware prominence can be prevented by seating the Kirschner wires in the olecranon, positioning the twisted wire loops away from the skin, and longitudinally incising the triceps tendon to place a plate directly on bone.
Between 34% and 66% of patients may require hardware removal.¹

3. Infection

Infections are unusual and occur in more complex injuries.

4. Nonunion

Nonunions are unusual, especially for simple fractures.

5. Ulnar Neuropathy

This complication may occur in up to 5% of cases.
Ulnar neuropathy usually resolves with conservative management.
Symptoms may develop as late as 4-6 weeks after the procedure, in which case the neuropathy may benefit from a release. If a patient presents with medial elbow pain and loss of range of motion after making good initial progress, consider delayed onset ulnar neuropathy.

6. Heterotopic ossification and stiffness

Stiffness is common is elbow injuries, but it is uncommon in olecranon fractures.
Stiffness increases with the complexity of the fracture.
Heterotopic ossification may occur and has been reported in up to 13% of cases of olecranon fracture.

7. Arthrosis

Severe arthrosis is uncommon with olecranon fracture, although some level of arthrosis may be seen in up to 20% of patients.

Pearls and Pitfalls

When using an anatomic olecranon plate for open reduction internal fixation of comminuted olecranon fractures, it is important to know whether the anatomic plate has the PUDA incorporated into the design. If the PUDA is not taken into consideration, then the radial head can sublux anteriorly.

Controversies

Hardware irritation is very common; it is reported in up to 71% of cases in which tension band is used. K-wires may also back out, although this is less likely to occur if the wires are engaging the volar cortex of the ulna rather than passing down the canal.

Biomechanical studies have shown braided cable to be stronger than stainless steel wire.

References

1. Bucholz RW, Heckman JD, Court-Brown CM, Tornetta P, Koval KJ. Rockwood and Green's Fractures in Adults: Rockwood, Green, and Wilkins' Fractures, 2 Volume Set. Sixth Edition. Lippincott Williams & Wilkins; 2005