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