Chapter 83. Radial Head Subluxation ("Nursemaid's Elbow") Reduction

Subluxation of the radial head is one of the most common pediatric orthopedic injuries. This can occur in children whose age ranges from less than 6 months to the preteens. The majority of radial head subluxations occur between 1 and 3 years of age.1 It is a rare injury before 1 year of age and after 8 years of age.

Historically, the classic mechanism involves axial or longitudinal traction on an extended elbow with the forearm pronated. This often occurs while someone is holding onto the child by the hand or wrist. While being held, the child is then pulled or the child falls and is suspended by the arm. The subluxation is seen more often in the left arm than the right. This is due to more people being right-handed and holding the child's left hand or wrist while walking. It is not uncommon, however, for the child to present with a history of a fall or rolling over in bed.1

This orthopedic injury involves the region of the elbow (Figure 83-1). The annular ligament is a thick band that wraps around the upper radial neck and radial head (Figure 83-1A). It guides the radial head as the forearm moves through pronation and supination. The injury causes the radial head to become partially dislocated from its articulation with the ulna and the capitellum of the humerus while the forearm is in a pronated state. The annular ligament then slips proximally and its lateral end becomes entrapped between the radial head and the capitellum (Figure 83-1B). The forearm becomes locked in pronation due to the entrapped annular ligament. This condition is painless as long as the forearm is held in pronation. Supination of the forearm causes pain, so the child holds the extremity in pronation. The act of supination would also spontaneously return the annular ligament to its anatomic position and reduce the subluxation.

Children will present in no apparent distress.2 They are usually resting comfortably and have some reservation in using the affected extremity. The arm will be held with slight flexion of the elbow and pronation of the forearm (Figure 83-2A). The child may point to an area of pain, but this is not often the case. A child may be much more comfortable with the parent examining and questioning areas of tenderness as opposed to the unknown and sometimes intimidating Emergency Physician.

Radiographs are not required unless other trauma or diagnoses are suspected. If radiographs are obtained, the child often returns from the radiology suite using the affected extremity. Radial head subluxations often reduce spontaneously during positioning for radiographs (Figure 83-2B).

Any child presenting with the inability to utilize the partially flexed elbow, the forearm pronated and adducted, and a mechanism for a radial head subluxation should be reduced. Many Emergency Physicians may be hesitant to repeat the procedure multiple times if a child was not utilizing the arm normally within 15 to 30 minutes after a clinically successful reduction. However, if the radiographs appear normal and a repeat history and physical examination are consistent with the original diagnosis, a decision to repeat the reduction should be considered.

The presence of edema, ecchymoses, tenderness other than over the radial head, suspicion of a fracture, or a mechanism of injury not consistent with a radial head subluxation should first be evaluated radiographically.2,8 The presence of any distal neurologic or vascular compromise excludes the diagnosis of a radial head subluxation.

No equipment is required for the reduction of a radial head subluxation.

Explain the risks, benefits, potential complications, and aftercare of the procedure to the child and their representative. Obtain a signed consent to perform the reduction. Place the patient sitting in the parent's lap or supine on an examination table or gurney. No premedication is required.

Supination and Flexion

Place one hand on the child's elbow with the thumb over the radial head (Figure 83-3A). This will aid in palpation of the traditional “click” of reduction. Gently grasp the child's wrist with the other hand (Figure 83-3A). Perform the following maneuvers in one smooth motion to reduce the subluxation. Apply distal traction while supinating the forearm (Figure 83-3B), followed by flexion of the elbow (Figure 83-3C). A click may be felt as the radial head is reduced.1,4 If not, flex the forearm until the hand is upright. Other methods of reduction are often compared to this method.3,5

If you feel the traditional click or feel satisfied with the attempted reduction, allow 5 to 15 minutes to pass and return for a repeat examination. Children may cry at the end of the procedure but will generally only do so for a moment. As the child feels more comfortable, they will proceed to use the arm (Figure 83-2C). This freedom of use can be accelerated by the caregiver or physician stimulating the patient to use the arm with an incentive (e.g., by offering candy, a pen, or a popsicle for the child to grab).

Hyperpronation

Position the patient as described above. There are two variations on this technique. The first holds the child's elbow at 90° of flexion and hyperpronates the forearm without any additional flexion at the elbow (Figure 83-4).5 The second holds the child's elbow at 90° of flexion and hyperpronates the forearm while simultaneously fully flexing the elbow (Figure 83-5).9 Both of these techniques can successfully reduce a radial head subluxation. Some feel that hyperpronation causes less pain to the child than the supination technique.5,9–11 This is because the arm is already being held in pronation and the additional pronation (hyperpronation) requires less force and motion than the supination technique.

The child should have uninhibited use of the forearm within 30 minutes. If not, reconsider the diagnosis. Alternative diagnoses include clavicular fractures, distal humeral fractures, osteomyelitis, radial head fractures, septic arthritis, and stress fractures. Reevaluate the elbow joint for signs of trauma. Obtain plain radiographs if not done previously. Full recovery may take 24 to 48 hours if the reduction is delayed for more than 8 hours from the time of injury.

Radiographs, immobilization, splinting, analgesics, and orthopedic follow-up are not necessary if the subluxation is reduced and the child is using their arm. Educate the caregiver regarding the mechanism of injury and prevention of future subluxations.6,7

Phone consultation with an Orthopedic Surgeon is recommended if the reduction is unsuccessful. It is not unusual to have a spontaneous reduction on repeat examination and follow-up. Immobilize the arm until the child is evaluated by an Orthopedic Surgeon. Immobilization will aid in pain relief. Consider the use of nonsteroidal anti-inflammatory drugs.

There are no complications associated with the reduction of a radial head subluxation.

A radial head subluxation is one of the more common orthopedic injuries of childhood. Children present with the inability to utilize the affected upper extremity. They hold the forearm flexed, pronated, and adducted. The reduction technique is quick and simple. It is important to educate the caregivers regarding the mechanism of injury and prevention of future subluxations.