Pretest

Introduction

Distal humeral physeal fractures are most common when the epiphysis is largely cartilaginous. Therefore they occur most often in the very young child but may be seen in children up to 6 years of age. Physeal fractures may occur in the process of a difficult childbirth. If they occur in the infant or toddler, child abuse must be considered.

Clinical and Radiographic Features

Both clinically and radiographically, a physeal fracture inthis region resembles an elbow dislocation. In the child whose capitellum hasnot yet ossified (Slide 1A and Slide 1B), there may be no osseousevidence that the distal humeral epiphysis is displaced. Elbow dislocations areextremely rare in children younger than 6 years of age (Slide 1C).¹ The distal humeral physealfracture may be a Salter I (Slide 2A) or II (Slide 2B) injury. In a Salter II injury, the metaphysealfragment is most often lateral. Therefore, the capitellum and the metaphysealfragment are laterally based and may resemble a lateral condyle fracture onradiograph. The distinction may be made on physical exam, however, by the morecircumferential swelling seen in the Salter II injury, and presence of medial,as well as lateral tenderness. There is a subtle radiographic difference, forin a Salter II injury the radius and ulna are translated as a unit with theentire distal humeral fragment, whereas in a lateral condyle fracture the ulnashould not shift because it remains articulated with the trochlea. If thediagnosis is in question, a magnetic resonance imaging (MRI) scan, ultrasound,or an arthrogram may assist in making the correct diagnosis. If an MRI isobtained, the elbow must be splinted in extension to allow the extremity to bepositioned for the most interpretable image.²

SLIDE 1A		SLIDE 1B		SLIDE 1C

SLIDE 2A		SLIDE 2B

Treatment

Treatment of the newborn or older child with a minimallydisplaced physeal fracture should be by closed reduction and immobilization ofthe elbow in flexion to allow the thick periosteal hinge to hold reduction. Inthe child of any age with significant displacement, the fracture must bereduced and held with percutaneous pins (Slide 3, Slide 4A and Slide 4B).³ Because the medial epicondyle is not ossified at this young age, its location must beassessed by palpation. If it is difficult to locate because of swelling, aminimal incision may be made over it or else the pins may both be placedlaterally. These physeal fractures are more stable than supracondylar fracturessince they occur through the broader physeal surface, not the thinsupracondylar bone. Immobilization for 4 weeks is sufficient. Avascularnecrosis of the trochlea may occur rarely, presumably due to interruption ofthe lateral trochlear transphyseal vessels. In follow-up of a series ofchildren under age 3, varus deformity was seen in the majority of cases. It wasfelt to be due to a combination of incomplete reduction and avascular necrosisof the trochlea. The results were best with those treated by closed reductionand percutaneous pin fixation.

SLIDE 3		SLIDE 4A		SLIDE 4B

References

1. Beaty JH, Wilkins KE. Fractures involving the entire distalhumeral physis. In: Rockwood C, Wilkins KE, Beaty JH, eds. Fractures inChildren. Philadelphia, Pa: Lippincott-Raven, 1996:790-895.



2. Sponseller PD. Problem elbow fractures in children. Hand Clinics 1994; 10:495-505.



3. Oh CW, Park BC, Ihn JC, Kyung HS. Fracture-separation ofthe distal humeral epiphysis in children younger than three years old. J Pediatr Orthop. 2000; 20:173-176.