The Case

A four year old male fell awkwardly in a trampoline, with his right wrist flexed, landing on the dorsum of his hand. He felt immediate pain and cried for a solid 30-minutes following the injury. Pain is most significant with palpation at the location of the radial physis and when he supinates.

AP and lateral plain radiograph of the right wrist. Courtesy of Brad Sobolewski (me)

The X-Ray is read as normal, but the young man was splinted because of ongoing pain. Over the next few days he was hesitant to use the arm and continued to be in pain at the physis and was placed in a short arm cast upon Orthopedic follow up.

The Diagnosis

A normal X-Ray does not necessarily mean that there’s not a fracture. In fact, at the 3 week mark during follow up a subsequent X-Ray was done, and it was also normal. But given the age of the patient and the persistent pain at the physis the diagnosis of a Salter Harris I fracture of the right radius was made.

Discussion

Recall that Salter-Harris is the main classification system for pediatric growth plate fractures. Read this recent post for a detailed description of the different types. Salter Harris type I fractures extend through the entirety of the growth plate (physis). The mechanism of injury is shearing across the entirety of the growth plate.

They are often NOT visible on x-ray, so a physical exam is key. In general if there is tenderness along the entirety of the physis then you should assume that there is a fracture present. If there is asymmetry at the growth plate then this is a more significant version of the Salter-Harris type I and the risk of later growth arrest is non-zero.

If there is minimal displacement or the X-ray appears normal splint and refer to Pediatric Orthopedics within 1 week for casting if pain persists. Younger patients like this one will heal quickly and may only need to be casted for 3-4 weeks.