A 5 y/o M presents to the ED w/ severe L arm pain following a fall off a jungle gym. On exam, he has a noted deformity of his L elbow and a small bruise just above his AC fossa. His radial pulse is diminished. An xray is obtained and shown below. What's the diagnosis? (scroll down for answer)

Answer: Supracondylar fracture

• Most common pediatric fracture
• Uncommon in adults
• Usually seen in kids 5-7 yrs old; mechanism= FOOSH
• On exam, patients with pain, refuse to move elbow
• Diagnosis can be made w/ elbow XR alone, no further imaging necessary
• Gartland Classification of Supracondylar Fractures:
• Type 1: nondisplaced, can be difficult to visualize on XR (may only see anterior or posterior fat pad, or displacement of anterior humeral line- which should intersect the middle 3rd of capitellum). Treatment= immobilization w cast, nonsurgical
• Type 2: displaced in sagittal plane only, fracture seen on XR, but posterior cortex humerus intact. Treatment= closed reduction, percutaneous pinning 
• Type 3: displaced in 2-3 planes, posterior cortex of humerus is not intact. Treatment = closed reduction, percutaneous pinning
• Type 4: complete periosteal disruption, humerus fracture is usually significantly displaced in multiple planes, rotated. Unstable flexion/extension of elbow. Treatment = closed or open reduction, percutaneous pinning
• Supracondylar fractures, especially when displaced, are at risk of causing vascular injury and possible nerve injury 
• "Brachialis sign" (also known as "pucker sign"):  exam w/ ecchymosis over AC fossa= indicates that humeral fragment penetrated through brachialis muscle w possible brachial artery injury
• On exam: be sure to assess radial pulses, color of hand, cap refill time! 
• Also be sure to assess function of anterior interosseus nerve (AIN = branch of median nerve)-- this is most common associated nerve injury and can be tested by asking patient to make OK sign w/ thumb and index finger
• Outcome: This patient had Type 4 supracondylar fracture w positive brachialis sign and vascular compromise noted by weak L radial pulse--> taken emergently to OR for open reduction/pinning