A 76 yo female presents after a fall on an outstretched right arm.  She has right elbow pain, tenderness, and swelling.  An xray is shown.  What's the diagnosis?  Scroll down for answer.

Answer:  Supracondylar fracture of the distal humerus

Mechanism

• Most commonaly, a fall on an outstretched arm

Types

• Type I: undisplaced
• Type II: displaced with intact posterior cortex
• Type IIa: no rotational deformity
• Type IIb: rotational deformity
• Type III: complete displacement

Diagnosis

• Clinical signs/symptoms
• Pain on passive extension of elbow
• Usually a forearm held in pronation
• Imaging
• Sail sign: anterior fat pad is elevated by a joint effusion, appears as a lucent triangle on the lateral projection
• Posterior fat pad sign, a lucency in the olecranon fossa on the true lateral elbow xray with elbow flexed at 90 degrees
• Anterior humeral line should intersect the middle third of the capitellum on the ture lateral xray.

Management

• Type I: stable, immobilization and prompt out patient orthopedic follow up
• Type IIa: immobilization flexed at 120 degrees vs surgical pinning
• Type IIb: reduction +/- fixation
• Type III: Closed reduction and percutaneous pinning vs open reduction

Complications 

• Volkmann ischemic contracture: forearm compartment syndrome due to damage/occlusion of the brachial artery
• damage to the ulnar, median or radial nerves
• most commonly anterior interosseous nerve (branch of the median nerve) causing weakness of hand flexors (difficulty making the OK sign) and abduction of the thumb

References

Tintinalli, JE. Tintinalli's Emergency Medicine: A Comprehensive Study Guide. 8th ed. New York, NY: McGraw-Hill Education LLC, 2016.