What's the Diagnosis? By Dr. Michael Tom

A 19 yo M presents to the ED complaining of elbow pain after running into a wall with an outstretched arm. His elbow is swollen, tender and ROM testing elicits pain. An xray is obtained. What's the diagnosis?  (scroll down for answer)


Diagnosis:  Radial Head Fracture

  • Can be subtle on plain films
  • On xray above:
    • large anterior fat pad (sail sign);  small anterior fat pad can be physiologic
    • posterior fat pad (always pathologic, suggests fracture)
    • malalignment of the radiocapitellar line
  • Of note: in adults, these fat pads are suggestive of radial head fracture while in pediatrics, they suggest supracondylar fracture
  • Radial head fracture is the most commonly seen elbow fracture
  • Exam often reveals pain to palpation of the lateral elbow, pain worse w/ supination and pronation
  • Common mechanism is FOOSH
  • If no or minimal displacement, can be treated conservatively with immobilization and orthopedic follow up
  • When associated with concurrent disruption of the interosseous membrane of distal radio-ulnar joint= Essex Lopresti Fracture