Articulations of the Elbow Joint (

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


  • 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


  • 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 (

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 (

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 (

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.


  • 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


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