A 7-year-old girl is brought to the emergency department due to a right arm injury. While jumping on a trampoline, she slipped and fell onto her outstretched right hand. The patient had immediate pain and would not move her arm. She did not hit her head or lose consciousness. On examination, the patient is crying in pain, with significant ecchymosis and swelling just above the elbow. She is holding the right arm in flexion and winces when it is moved. X-ray reveals a supracondylar fracture with posterior displacement of the distal humerus fragment, as shown in the image below. Which of the following is at greatest risk of injury in this patient?

Question

A 7-year-old girl is brought to the emergency department due to a right arm injury.  While jumping on a trampoline, she slipped and fell onto her outstretched right hand.  The patient had immediate pain and would not move her arm.  She did not hit her head or lose consciousness.  On examination, the patient is crying in pain, with significant ecchymosis and swelling just above the elbow.  She is holding the right arm in flexion and winces when it is moved.  X-ray reveals a supracondylar fracture with posterior displacement of the distal humerus fragment, as shown in the image below.  Which of the following is at greatest risk of injury in this patient?

Quizplus · Accepted Answer

11ec25c8_d97b_83bd_bc81_c9846012fe2c_MD0003_00 Supracondylar fractures of the humerus are the most common elbow fractures in children. The mechanism typically involves a fall onto an outstretched hand with a hyperextended elbow. The supracondylar area is relatively thin and weak due to physiologic remodeling during childhood, and a supracondylar fracture most commonly results in posterior displacement of the distal humerus fragment, as seen in this patient. The anteriorly displaced proximal fragment can entrap the median nerve and brachial artery, which are located anterior to the humerus. Distal perfusion should be monitored closely because brachial artery injury results in diminished brachial and radial pulses. Motor and sensory function should also be assessed due to the risk of median nerve injury that can present with a weak "OK" sign (ie, inability to approximate tip of thumb and index finger). Diagnosis is based on x-ray, which reveals a fracture line and often a posterior fat pad indicative of elbow effusion. Treatment involves analgesia and immobilization. Neurovascular injury often resolves after orthopedic alignment and immobilization. Patients who are treated promptly have a good prognosis. x-ray (Choices A and B) The axillary artery and nerve can be injured during proximal humerus fractures but not with supracondylar fractures. (Choice D) Brachial plexus compression is a complication of neonatal clavicle fracture or high-impact trauma to the neck and shoulder area, not the elbow. (Choice E) Ulnar nerve injury is a complication of a rare type of supracondylar fracture that occurs upon impact of a flexed (rather than hyperextended) elbow. This mechanism of injury causes anterior displacement of the distal humerus fragment, which can impinge on the ulnar nerve located posterior to the medial epicondyle of the humerus. Educational objective: Displaced supracondylar fractures of the humerus most commonly present after a fall onto an outstretched hand with posterior displacement of the distal humerus fragment. The anteriorly displaced proximal humerus fragment can entrap the brachial artery and median nerve, which pass anterior to the humerus. References: Elbow fractures overview. (http://www.ncbi.nlm.nih.gov/pubmed/28723005) Analysis of early neurovascular complications of pediatric supracondylar humerus fractures: a long-term observation. (http://www.ncbi.nlm.nih.gov/pubmed/28367440)

A 7-Year-Old Girl Is Brought to the Emergency Department Due