Review Question - QID 210231

This patient sustained a flexion-type supracondylar injury. The most common nerve injured with this fracture pattern is the ulnar nerve, which should initially be observed.

Supracondylar fractures of the distal humerus are common injuries in children and represent a medical urgency because of the possible associated neurological and vascular injuries. The incidence of neural injuries associated with this fracture pattern have been reported to range from 5% to 19%. In extension-type fractures, displacement occurring posteromedially is associated with radial nerve injuries, whereas posterolateral displacement is more likely to cause a median nerve injury. The ulnar nerve is more commonly injured in flexion-type injuries. Nerve injuries should initially be observed unless they represent an acute change postoperatively. In the flexion-type injury, it is important to be aware that open reduction may be needed more frequently than extension type injuries and especially when a nerve injury is also present.

Valencia et al. performed a review of 448 children with supracondylar humerus fractures. 6.5% of patients had a nerve injury. The median nerve was injured in 13 patients, the radial nerve in 14 patients, and the ulnar nerve in 9 patients. At final follow-up, 100% of the radial nerve injuries and 87.5% of the median nerve injuries were fully recovered, however, only 25% of the ulnar nerve injuries had recovered.

Abzug et al. performed a review of supracondylar humerus fractures in children. They report that a change in the patient's neurologic examination postoperatively is more concerning than a pre-operative deficit. This may indicate that the affected nerve was injured during manipulation or pinning and may be trapped in the fracture site. They conclude that, in this situation, exploration of the nerve may be required to prevent ongoing nerve injury.

Flynn et al. performed a study of flexion-type supracondylar humeral fractures and ulnar nerve injury. They found ulnar nerve injury in 10% of fractures. They found that nearly 23% of flexion-type injuries required open reduction, and open reduction was even more likely with ulnar nerve injury. They conclude that the flexion-type injury pattern was associated with a 15.4-fold increase in the odds of open reduction. The presence of an ulnar nerve injury at presentation resulted in an additional 6.7-fold higher risk of open reduction among flexion-type supracondylar humeral fractures.

Figures A & B are AP and lateral elbow radiographs demonstrating a flexion-type supracondylar fracture.

Incorrect Answers:
Answers 1, 2, & 4: AIN palsies are most commonly seen in extension-type injuries. They should be treated with observation in most cases.
Answer 3: Ulnar nerve injuries should initially be treated with observation.