Introduction          

Olecranon fractures are relatively common injuries, accounting for approximately 10% of upper extremity fractures in adults [18]. These fractures may result from a direct blow to the proximal ulna, or indirectly, via the forceful contraction of the triceps against resistance (typically, during a fall onto an outstretched hand). Less commonly, the olecranon may fracture when the elbow is hyperextended, as the bone is impacted against the olecranon fossa of the distal humerus.  For unstable injuries, operative fixation is typically required.  Even after recovery, loss of range of motion is not uncommon.

Structure and Function         

The olecranon is the region of the proximal ulna that extends from the tip of the ulna to the coronoid process. Three main anatomic features must be recalled when treating fractures of the olecranon. First, the olecranon is the site of insertion of the triceps—a muscle whose action would tend to displace a fracture. Second, the trochlear notch of the olecranon forms a cavity in which the distal humerus sits [9] and thus all olecranon fractures, by definition, are intra-articular injuries. Last, the posterior process of the olecranon prevents posterior translation of the humerus (just as the coronoid process prevents anterior translation) and thus displacement can lead to elbow instability.

Injury Considerations

Olecranon fractures are typically seen in young individuals after high-energy trauma or in the elderly after low energy falls. Although olecranon fractures most commonly occur as isolated injuries, it is essential to evaluate all patients for other injuries. Specifically, injuries to the ipsilateral extremity must be identified, including elbow fracture-dislocations, as these injuries may alter the treatment plan and impact clinical outcome.  

Diagnosis and Classification          

The typical presentation of a patient with an olecranon fracture is elbow pain and 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.

Isolated olecranon fractures can be appropriately identified with standard anteroposterior and lateral radiographs of the elbow. 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. Radiographs should be carefully examined for evidence of coronoid process fracture, dislocation of the elbow, and radial head injury. More advanced imaging is rarely indicated for isolated olecranon fractures.

Several classification systems have been described but none has been universally accepted. The Mayo classification [2], based on displacement and ulnohumeral joint stability, is our preferred choice as it can be used to guide treatment:

  • Type I: nondisplaced fractures, treated non-operatively;
  • Type II displaced, stable fractures that require operative fixation;
  • Type III displaced, unstable fractures that require surgical fixation.

The Schatzker classification [20] subdivides fractures based on their pattern into transverse, transverse-impacted, oblique, comminuted with associated injuries, oblique-distal, and fracture-dislocation. The AO classification of proximal radius and ulna fractures tends to be used more frequently for research purposes.

Treatment

The goals of treating olecranon fractures are anatomic restoration of the articular surface, repair of the elbow extensor mechanism, restoration of elbow joint stability and motion, and prevention of stiffness and other complications. Treatment options include imobilization, surgical reduction and fixation with tension-band wiring or plate osteosynthesis, and excision of the proximal fragment with triceps advancement.

Non-operative treatment is rarely indicated, but may be considered for patients with a non-displaced fracture that does not displace at 90 degrees of elbow flexion and has an intact extensor mechanism or for partial avulsions of the triceps insertion with intact extensor mechanism. It may also be considered for poorly functioning older adults who would not tolerate surgery. Treatment involves immobilization of the elbow in a posterior splint, orthosis, or long-arm cast in approximately 90 degrees of flexion for approximately 3 weeks, followed by progressive active elbow range of motion and strengthening [16].

Surgical fixation should be performed when there is articular incongruity or disruption of the extensor mechanism. Tension-band wiring [22] has been shown to provide stable fixation and good clinical results for simple transverse olecranon fractures [5,23]. This technique involves the insertion of two parallel Kirschner wires or an intramedullary cancellous screw from the tip of the olecranon aiming distally across the fracture site, with placement of a metal wire (or heavy suture) in a figure-of-eight pattern. A tension band construct converts the tensile distraction force of the triceps into a compressive force at the articular surface [11]. Cadaveric studies have shown that tension band fixation with a cancellous screw provides better fixation than tension band fixation with Kirschner wires or a cancellous screw fixation without a tension band for transverse olecranon fractures [7].

Plate fixation is the best treatment for olecranon fractures that are not amenable to tension-band fixation, specifically comminuted fractures, oblique fractures distal to the midpoint of the trochlear notch, fractures involving the coronoid process, and fractures associated with fracture-dislocations of the elbow. Plate fixation of olecranon fractures has been shown to provide stable fixation and good clinical outcomes [1,3-4,21]. Many surgeons may elect to perform plate fixation for the majority of olecranon fractures as this provides more stable fixation (especially in rotation), reserving tension band wiring for simple, transverse, non-comminuted fractures [19]. Plates are typically placed on the dorsal surface of the proximal ulna (see Figure 1). Several different types of plates can be used, including one-third tubular, limited contact dynamic compression, hook and pre-contoured locking plates. Specific plate preference and fixation are dictated by the fracture pattern, bone quality, and surgeon preference.

Excision of the proximal bony fragment and triceps advancement [8] is rarely used in the setting of primary treatment of olecranon fractures. It should only be considered for isolated olecranon fractures in debilitated older adults with limited functional demands [16].

Anatomic restoration of the articular surface and stable fixation of olecranon fractures are required to allow early elbow range of motion to prevent stiffness and maximize the patient’s functional outcome.

Future directions include the continued development of lower profile and contoured plates, in addition to new implants such as intramedullary nails [14,10] for the treatment of olecranon fractures.

Outcomes

Olecranon fractures heal well in most instances. Functional outcome is dependant on fracture severity, length of immobilization, and host factors. The main complication following surgical management of olecranon fractures is symptomatic hardware, with tension band wiring having a higher incidence than plate fixation [6,23]. Painful hardware can be removed after fracture healing is complete. Tension band wiring has a higher reoperation rate because of the frequent need for hardware removal due to the subcutaneous placement of K wires and a higher resultant risk of pain, skin breakdown, and infection [17]. Loss of terminal extension is frequently seen — and patients should be advised of this — but is rarely clinically significant in the setting of isolated olecranon fractures. Nonunion of olecranon fractures is rare [15]. Additional complications include hardware failure, infection, ulnar neuritis, heterotopic bone formation, and elbow stiffness.

Five Pearls

1.     A true lateral radiograph of the elbow is the most important imaging study for the identification of the extent of articular displacement, comminution and fracture pattern.

2.     Olecranon fractures are, by their very nature, intra-articular injuries (which should be reduced anatomically) and require the restoration of congruency for proper joint function.

3.     Tension band wiring has excellent outcomes for simple transverse fracture patterns but often requires hardware removal; plate fixation should be considered for fractures and injury patterns where greater rotational stability is desired.  

4.    A patient with an olecranon fracture may seem to be able to actively extend the elbow, by using gravity for this action. Always check extension against gravity or mild resistance.

5.     There are soft tissue retinacula on either side of the olecranon, so with some non-displaced fractures the extensor mechanism may be intact and conducive to non-operative treatment.

References

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17. Romero JM, Miran A, Jensen CJ. Complications and reoperation rate after tension-band wiring of olecranon fractures. J Orthop Sci. 2000;5:318-320.

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19. Sahajpal D, Wright TW. Proximal ulna fractures. J Hand Surg. 2009;34A:357-362.

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21. Simpson NS, Goodman LA, Jupiter JB. Contoured LCDC plating of the proximal ulna. Injury. 1996;27:411-417.

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