Case 13 - Child With a Sprained Wrist

A ten year old boy fell during a soccer game, injuring his right wrist. He reportedly tripped when trying to kick the ball and landed backwards on his outstretched right hand. After the patient complained of pain and swelling in the right wrist, ice was placed on his wrist and he was brought to the ED.

Exam: The right distal wrist is tender with mild swelling. There is point tenderness over the volar lateral aspect of the distal radius. There is a mild amount of loss of range of motion of the right wrist in flexion, extension, abduction, and adduction. Deformity and ecchymosis are not present. No tenderness or deformities are present in the fingers, hand, mid and proximal forearm, elbow, humerus, shoulder, or clavicle. Full range of motion is present in the hand, elbow, and shoulder. There is no tenderness in the anatomic snuff box. Radiographs of the right wrist are taken.

View radiographs of wrist. 

Clinically, he appears to have a fracture over the distal radius where there is point tenderness and mild swelling. Do you see the fracture?

This is normal. No fracture is seen. The growth plate is not widened, nor is there any displacement of the epiphysis from the metatphysis. However, this does not mean that a fracture is ruled out.

Teaching Points:

1. 1. Salter-Harris Type I injuries are based on clinical suspicion. This is often a clinical diagnosis rather than a radiographic diagnosis. Tenderness and/or edema at the growth plate are more diagnostic than normal radiographic findings. Type I fractures are only visible radiographically if the segments are displaced; however, this is uncommon.
   
   View example of displaced SH Type I fracture. 
   
   
   In this radiograph, the AP view of the wrist looks normal except for a small chip fracture of the ulnar styloid. In examining the lateral view, describe the position of the radial epiphysis in relation to the metaphysis. Note that the epiphysis is not centered over the metaphysis. The epiphysis is displaced dorsally relative to the metaphysis indicating radiographically, a displaced Salter-Harris Type I fracture. See Case 18 (Salter-Harris) for more information.
2. SH Type I fractures of the distal radius are common. Ulnar involvement is not common.
3. The fall on the outstretched hand is the mechanism of injury most commonly associated with fractures of the distal radius and ulna.
4. A sprained wrist is a diagnostic pitfall that should be avoided. The patient in this case does NOT have a sprained wrist. Tenderness over the physis region of any bone, especially at the wrist, is a Salter-Harris I fracture until proven otherwise by special studies or long term follow-up, even if initial radiographs are normal. 5. What might appear to be an ankle sprain may also turn out to be a SH type I fracture of the distal fibula. The patient's history may not be very helpful, since both an ankle sprain and a fibula fracture may be difficult to distinguish. On examination, a Salter Harris type I fracture will be tender directly over the distal fibular physis. An ankle sprain may be tender more distally where the ligaments/syndesmosis attach the fibula to the talus. This is a clinical diagnosis as well. Sometimes, there is evidence of rotation or displacement of the distal fibular epiphysis, but the absence of this does not rule out a non-displaced type I fracture.

View ankle SH-I example.

This patient presented with an ankle injury. He was noted to have only mild swelling over the lateral malleolus, but he refused to bear weight on the foot, preferring to hop instead. He was not tender over the distal tip of the fibula, but he was very tender more proximally, over the fibular physis. He was placed in a splint for a suspected Salter Harris Type I fracture of the distal fibula. At orthopedic follow-up, he was placed in a short leg cast for 17 days. Upon removal of the cast, he had no pain, and he could bear weight without problems. It is difficult to say with certainty whether this truly was an SH-I fracture of the distal fibula; however, this diagnosis should be considered when examination findings suggest it.

Reference:

1. Lawton LS. Fractures of the Distal Radius and Ulna. In: Letts RM (ed). Management of Pediatric Fractures. New York, Churchill Livingstone, Inc., 1994, pp.345-368.
2. Rang M. Children's Fractures. Philadelphia, J.B. Lippincott Co., 1983.
3. Anderson AC. Injury-Ankle. In: Fleisher GR, Ludwig S (eds). Textbook of Pediatric Emergency Medicine, third edition. Baltimore, Williams & WIlkins, 1993, pp. 259-267.