Olecranon Fractures

Articulations of the Elbow Joint (teachmeanatomy.info)

Definition: Fracture of proximal ulna at the level of articulation with humerus

Mechanism

• Most commonly  secondary to direct trauma to olecranon
• Fall on outstretched hand with flexed elbow
• Low-energy  fractures are due to abrupt contraction of both the triceps and brachialis muscles
• Stress fracture is less common and seen predominantly in throwing athletes (e.g. baseball) with a gradual onset of pain worse with repeated throwing motions

Epidemiology

• Represent 10-20% of upper extremity fractures (Schwartz 2008)
• Olecranon fractures in younger patients are often due to high-energy direct trauma
• Elderly patients can sustain olecranon fractures from low-energy mechanisms such as a fall from standing

Physical Exam

• Palpable defect may be appreciated with displaced  or comminuted fractures
• Posterior elbow tenderness to palpation with associated joint swelling
• Forearm Extension
  • Triceps inserts into the posterior proximal ulna
  • Commonly associated with a displaced olecranon fracture
  • Loss of forearm extension by the triceps muscle
  • Test forearm extension against resistance. Loss of extension mechanism can be masked if patient simply allows arm to drop with gravity
• Perform full neurovascular exam
  • Confirm presence and strength of circulation distal to injury at both ulnar and radial arteries. 
  • Look for signs of hypoperfusion such as a pale limb, prolonged capillary refill, and decreased limb temperature
  • The ulnar nerve runs posterior to the medial epicondyle into the cubital tunnel and can be injured with olecranon fractures.
  • Check for sensory deficits  over the palmar surface of the fifth digit and motor weakness in interossei muscles of the hand. Abnormalities indicates ulnar nerve injury
• Closely examine  for lacerations,  which could suggest open fracture given close proximity of olecranon and overlying skin
• Test elbow instability and for ligament injury
  • Apply varus and valgus stress with elbow flexed at 30 degrees
  • Instability with varus stress indicates medial collateral ligament injury
  • Instability with valgus stress indicated ulnar collateral ligament injury.
• Assess for evolving compartment syndrome

Comminuted Olecranon Fracture (accessemergencymedicine.mhmedical.com)

X-Ray Findings

• Images required: AP, Oblique and True Lateral
• Importance of True Lateral
  • Shoulder, elbow and wrist must be in the same plane to assess the anterior humeral, radiocapitellar line, and olecranon.  Elbow in 90 degrees flexion
  • Normal: Proximal radial lines meets anterior humeral line approximately center of capitulum.  Supracondylar ridge is in hourglass or figure 8 at distal humerus. 
  • Without a true lateral elbow film it is difficult to accurately determine amount of fracture displacement and intra-articular involvement (both are needed for classification and management)
• Unopposed tricep muscle action after fracture can cause wide displacement of fracture.
• Look for associated fractures or dislocations of coronoid process, radial head, and distal humerus
• CT may be needed for surgical planning

AO Classification (http://musculoskeletalkey.com/)

Classification Systems

• Unstable Fractures
  • Significant displacement (> 1-2 mm)
  • Loss of extension at the elbow
  • Elbow instability on exam
  • Evidence of neurovascular compromise
  • Open fractures
• AO Classification System 
  • Simplest and most commonly used
  • Combines proximal ulna and radius fractures into one group
  • AO Classification
    • Type A: extra-articular
    • Type B: Intra-articular
    • Type C: Intra-articular fractures of both the radial head and olecranon
• Mayo Classification System
  • Based on stability and displacement/comminution of the fracture
  • Mayo Classification
    • Type 1: Non-displaced with non-comminution (subtype A) or comminution (subtype B)
    • Type II: Displaced > 3 mm but collateral ligaments are intact, considered stable. Can be non comminuted (subtype A) or comminuted (subtype B)
    • Type III: Displaced and unstable, forearm unstable in relation to humerus, assumes ligamental compromise, can be either non-comminuted (subtype A) or comminuted (subtype B)

Mayo Classification (http://image.slidesharecdn.com/)

ED Management

• Unstable fractures, as detailed above, require emergent orthopedic consultation for operative fixation.
  • Apply splint at 50-90% flexion and analgesia.
  • Intravenous antibiotics for open or suspected fractures.
• Stable, nondisplaced fractures with intact extensor function
  • Immobilized in a long arm posterior splint with 90 degrees of flexion, neutral forearm
  • Orthopedic follow up within 1-2 days.

Prognosis

• High rate of union with appropriate treatment >90% (Chow 2006)
• Nondisplaced fractures can begin range of motion exercises at 1 week.
• The most frequently patient-reported complication after surgery is painful hardware.  After fracture is healed hardware can be removed. 
• Depending on surgical technique more than 20% of patients require a second surgery for hardware removal (Wheeless 2013)
• Patients may have a permanent 10-15 degree loss of extension (Wheeless 2013)

Take Home Points

• Appreciation of loss of elbow extension mechanism or elbow instability on physical can help determine need for surgical intervention
• Olecranon fractures can be associated with injury to the ulnar nerve, which runs posterior to the medial epicondyle into the cubital tunnel
• Posterior elbow lacerations should raise concern for open fracture
• Frequent reevaluations and high suspicion for compartment syndrome
• Low-energy mechanism of injury can cause olecranon fractures in elderly patients, maintain a  low threshold for imaging

Read more

Radiopedia: Olecranon fractures

Radiopedia: Lateral elbow x-rays

Orthobulltes: Olecranon fractures

References

Chow YC. Elbow and Forearm Injuries. In: Tintinalli JE, Stapczynski J, Ma O, Yealy DM, Meckler GD, Cline DM. eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 8e. New York, NY: McGraw-Hill; 2016.  Link

Germann CA. Elbow. In: Sherman SC. eds. Simon’s Emergency Orthopedics, 7e. New York, NY: McGraw-Hill; 2014.  Link.

Greenberg MI. Greenberg’s text-atlas of emergency medicine. Philadelphia : Lippincott Williams & Wilkins, c2005. (2005) ISBN:0781745861

Jordanov MI et al. .Chapter 9. Upper Extremity. In: Block J, Jordanov MI, Stack LB, Thurman R. Block J, Jordanov M.I., Stack L.B., Thurman R Eds. Jake Block, et al.eds. The Atlas of Emergency Radiology. New York, NY: McGraw-Hill; 2013.  Link

Schwartz DT. Chapter III-1. Elbow Fat Pad—Monteggia Fracture. In: Schwartz DT. eds. Emergency Radiology: Case Studies. New York, NY: McGraw-Hill; 2008.  Link

Wheeless, C. R. “Fractures of the Olecranon Duke Orthopaedics Wheeless’ Textbook of Orthopaedics.” (2013).  Link