Radial neck fractures occur most often from the ages of 4 to 14 years and are often associated with elbow injuries. Together, these injuries often cause outcomes that are less satisfactory than most pediatric fractures.
The child will have swelling over the proximal radius. Radiographs usually show the fracture. Be aware that to grade the severity accurately, the radiograph should show the fracture displacement in profile. The grade often is higher than expected from routine views. Undisplaced fractures can be imaged by ultrasound or MRI.
Classify the severity based on both displacement and angulation. Grade 4 injuries include those with the radial head displaced to a position to the proximal radius.
Manage based on severity.
Grade 1 These fractures require only resting in an arm sling until the pain has subsided.
Grades 2 and 3 These fractures may reduce with manipulation. With satisfactory anesthesia, rotate the forearm until the displaced radial head is most prominent. Apply thumb pressure while rotating the forearm to reduce the radial head. If reduction to a grade 1 level is not achieved, then percutaneous reduction is indicated. See next page.
Grade 4 This type requires open reduction. Internal fixation with a suture or pins may be necessary.
Complications include stiffness, avascular necrosis, growth arrest, overgrowth, malunion, nonunion, cross union, posterior interosseous nerve injury, and compartment syndromes.
Radial Neck Fracture Reduction and Fixation
Under fluroscopy, rotate the forearm while observing the fracture to show maximum displacement and tilt. If this displacement exceeds about 10% and the tilt 30°, reduction is necessary. Reduction of radial neck fractures can sometimes be successful by manipulation. Apply firm thumb pressure on the skin overlying the edge of the displaced fragment while rotating the forearm. If this is not successful, percutaneous reduction will be necessary. The simplest method involves levering the fragment back into place with a K wire. The more sophisticated method achieves reduction using an intramedullary pin.
Technique – K Wire Leverage Method of Steele and Graham
Under general anesthesia, prep and drape the arm free. Under fluoroscopic guidance, bring the fracture into profile. Place a 1.5–2 mm smooth K wire on a T handle chuck. Under fluoroscopy, position the entry point as far proximal as possible to avoid injury to the interosseous nerve. Move the K wire proximal to lever the head onto the radial neck. Overcorrection is prevented by the capitellum. To improve apposition, move the radial head with the K wire. Assess stability and motion by rotating the forearm. Rotation of 60° should be possible in both directions. If the fracture is unstable, transfix with a single oblique percutaneous K wire left out through the skin. Avoid transcapitellar fixation. Remove the optional fixation and allow gradual return to full activity.
Technique – Closed Intramedullary Fixation of Metaizeau
Make a short lateral incision about 1 cm proximal to the distal radial growth plate while avoiding injury to the cutaneous branch of the radial nerve. Perforate the cortex with a drill and insert a curved K wire 1.2–2 mm (depending upon the child’s age) with the terminal 3 mm bent more sharply. Hammer the pin into the medullary canal and manipulate to enter the displaced radial head. Advance the pin, moving the radial head against the capitellum. Position the radial head against the capitellum with the periosteum (green) as a tether correcting the tilt of the articular surface. Rotate the handle to medially displace the radial head to correct apposition and stabilize the reduction. The pin may be cut off under the skin or left protruding to facilitate removal. Apply a splint for 2–3 weeks. Remove the K wire at 2 months.
Avascular necrosis This complication is likely the result of the injury.
Malunion The risk of this complication is reduced by an accurate reduction.
Nonunion This is an uncommon complication.