Courtesy: Prof Nabil Ebraheim, University of Toledo, Ohio, USA

Supracondylar Fracture of the Humerus

Types

Extension type

• Most common, accounting for approximately 95 percent of cases.

Flexion type

• Uncommon.

Mechanism of Injury

Extension type

• Fall on an outstretched hand.

Flexion type

• Fall on a flexed elbow.

Nerve Injuries

Extension type

• The anterior interosseous nerve, a branch of the median nerve, is the most commonly injured.
• Inability to make the “OK” sign due to pinch grip weakness.
• Most injuries are neuropraxias and recover with conservative treatment.

Flexion type

• The ulnar nerve is the most commonly injured.
• Sensory loss over the medial one and a half fingers.
• Weakness of the interosseous muscles.

Iatrogenic injury

• Ulnar nerve injury may occur during medial pin insertion.

Management

Standard treatment

• Closed reduction and percutaneous pinning (CRPP).

Preoperative assessment

• Assess brachial artery pulse.
• Assess capillary refill.
• Perform a complete neurological examination.

Pin Configuration

Lateral pinning

• Two or three divergent lateral pins.
• Lower risk of ulnar nerve injury.

Cross pinning

• One medial and one lateral pin.
• Greater mechanical stability.
• Increased risk of ulnar nerve injury.

Medial pin technique

• Insert the medial pin through a small incision under direct vision to protect the ulnar nerve.

Implant Removal

• K wires are usually removed after approximately 3 weeks.

Complications

Cubitus varus

• Most common complication.
• Caused by malunion.
• Primarily a cosmetic deformity.
• Functional impairment is usually minimal.
• Corrective osteotomy may be required for severe deformity.

Volkmann ischemic contracture

• Most serious complication.
• Results from brachial artery compression.
• Tight casting and excessive elbow hyperflexion are common causes.
• Muscle ischemia leads to fibrosis and fixed flexion deformity of the hand.

Exam Pearls

• Extension type is the most common supracondylar fracture.
• The anterior interosseous nerve is the most commonly injured nerve.
• Volkmann ischemic contracture is the most serious complication.
• Cubitus varus is the most common late deformity.
• Closed reduction and percutaneous pinning is the treatment of choice for displaced fractures.