In adults, the radial head is wider than the radial neck; consequently, the head cannot fit through the ligaments that tightly surround the neck. However, in toddlers (about 2 to 3 years old), the radial head is no wider than the radial neck and can easily slip through these ligaments (radial head subluxation).
Subluxation results from traction on the forearm, as when a caregiver pulls a reluctant toddler forward or catches the toddler by the wrist during a fall—actions many caregivers do not remember.
(See Overview of Dislocations.)
Plain x-rays are normal and considered unnecessary by some experts when patients have a clear history of a traction injury, unless an alternate diagnosis is clinically suspected (1).
Using a reduction maneuver may be diagnostic and therapeutic.
Reduction may be done using
Neither technique requires sedation or analgesia; the child experiences pain only for a few seconds. Hyperpronation has a higher first-attempt success rate (1). (See also How To Reduce a Radial Head Subluxation.)
In supination-flexion, the elbow is completely extended and supinated, then flexed. A subtle palpable pop or click is often detected when the radial head resumes its normal position.
In hyperpronation, the practitioner supports the child's arm at the elbow and places moderate pressure with a finger on the radial head. The practitioner then grips the distal forearm with the other hand and hyperpronates the forearm. A pop can be felt at the radial head when it is reduced.
Children usually start to move the elbow after about 10 to 20 minutes. If they do not move it, x-rays of the elbow should be taken. If they do move it, x-rays and immobilization are unnecessary.
If pain or dysfunction lasts > 24 hours, incomplete reduction or an occult fracture should be suspected. Radial head subluxation recurs in 20 to 40% of children.
1. Bek D, Yildiz C, Köse O, et al: Pronation versus supination maneuvers for the reduction of 'pulled elbow': A randomized clinical trial. Eur J Emerg Med 16 (3):135–138, 2009. doi: 10.1097/MEJ.0b013e32831d796a
Radial head subluxation, common among toddlers, can occur when a caregiver pulls a reluctant toddler forward or catches the toddler by the wrist during a fall—actions many caregivers do not remember.
Most patients cannot describe their symptoms; the only indication of the injury may be unwillingness to move the affected arm.
Diagnose based on history unless an alternate diagnosis is suspected.
Treat by reducing the joint (using supination-flexion or hyperpronation); a subtle palpable pop or click is often detected when the radial head resumes its normal position.