Objectives
- Recognize the typical presentation of Radial Head Subluxation
- Understand the pathogenesis of Radial Head Subluxation
- Understand the approach to reduction techniques utilized in presentations of Radial Head Subluxation
Case Presentation
A 28 month old female presents to the Emergency department in the care of her mother. The patient’s mother reports that several hours earlier she and her daughter were holding hands on an afternoon walk. As her child stumbled toward the curb of a sidewalk, the mother quickly pulled the patient up by the hand and wrist to avoid a fall off the sidewalk and into the street. The mother admits that her daughter was momentarily lifted into the air before being placed back down onto her feet. Since the event, the patient has been unwilling to move her left arm for any reason. She resists any attempt of the mother to manipulate or move her arm. The mother is concerned that she may have injured her daughter’s wrist.
Introduction
Nursemaid’s Elbow, more accurately referred to as Radial Head Subluxation, is an injury unique to the pediatric patient. It is the most common elbow specific injury in the pediatric population. It typically occurs in children 6 months to 3 years. It has been reported up through pre-teen years but is rare past 4 years of age. Radial Head Subluxation occurs when the annular ligament slips away from the radial head, becoming entrapped within the radiohumeral joint (figure 1). The typical mechanism of injury includes axial traction on a pronated forearm as occurs during play or during common activities of daily living.
Exam
While all children with Radial Head Subluxation demonstrate limited to no movement of the affected arm, the actual position of the arm may be variable. Full extension at the elbow, a slightly flexed elbow, or an elbow flexed to 90 degrees may be observed. The extremity is held close to the body with the forearm most commonly pronated. A complete examination of the upper extremity is indicated starting proximally from the clavicle and proceeding distally to the wrist and digits. Tenderness may be produced with any manipulation and palpation over the radial head. Soft tissue swelling in any area of the extremity exam is uncommon with Radial Head Subluxation and should increase a suspicion of fracture. Any attempt to supinate the forearm will produce pain, fussiness, and anxiety as a result of the entrapped annular ligament.
Reduction
A child presenting with features typical of Radial Head Subluxation should undergo prompt reduction. Unless a fracture is suspected (as evidenced by swelling) imaging studies are not acutely indicated. The rapid and successful nature of proven reduction techniques obviates the need and risk of procedural sedation. Reduction does cause brief discomfort to the patient and it is imperative to prepare the parent or caregiver prior to any attempted manipulation of the extremity.
Two reduction techniques described and commonly utilized in clinical practice include Hyperpronation and Supination/Flexion. While there is an abundance of literature evaluating the two methods, no one technique has been proven superior over the other, indicating that both constitute a reasonable approach an initial reduction attempt.
Hyperpronation
Hyperpronation has been described with or without a flexion component. With the child ideally seated in the parents lap, facing the examiner, the radial head is located and pressure is applied with the thumb or index finger. With pressure applied to the radial head in a medial direction, the examiner’s opposite hand firmly grasps the distal forearm and applies hyperpronation. A palpable and/or audible click may be appreciated at the time of successful reduction. A variation to hyperpronation includes the additional application of flexion at the time of maximal hyperpronation. At the end of the maneuver, the elbow is extended and released.
Supination/Flexion
Similar to Hyperpronation, the Supination/Flexion technique includes placing the child in a caregivers lap facing the examiner. The radial head is located and pressure is applied with the thumb or index finger. With the examiners opposite hand, axial traction with supination and flexion of the elbow past 90 degrees is applied in one smooth motion. A palpable or audible click may be appreciated at the time of successful reduction.
Used with permission from Nationwide Children’s Hospital
Post Reduction
Response to a successful reduction is variable. A patient may resume usual activity of the affected extremity with unlimited range of motion immediately following reduction. More commonly, a patient will remain apprehensive and unwilling to demonstrate spontaneous movement, as the manipulation will have caused brief pain and heightened anxiety. As such, reassessment in a 5–20 minute interval with the caregiver encouraging use of the extremity is generally sufficient to determine reduction success. If the patient does not demonstrate spontaneous movement on reassessment, a second reduction attempt with the same or alternate technique should be trialed.
Recurrence of Radial Head Subluxation ranges between 27 and 39 percent. No long-term sequelae are associated with single or multiple presentations of this injury. Anticipatory guidance should be provided to all parents and caregivers with an emphasis on future prevention.
Case Resolution
The patient’s presentation is highly suspicious for acute Radial Head Subluxation. With no alternate injury identified on examination, a careful explanation of the child’s suspected injury along with the therapeutic solution is discussed with the mother. Hyperpronation is successfully applied resulting in a gratifying, palpable “click”.
References
- Bachman D, Orthopedic Trauma: Textbook of Pediatric Emergency Medicine, 5th, Fleisher GR, Ludwig S, Lippincott Williams and Wilkins, Philadelphia 2006. P. 1525
- Macias CG, Bothner J. A comparison of supination/flexion to hyperpronation in the reduction of radial head subluxations. Pediatrics 1998; 102, e10
- Schunk JE. Radial head subluxaton: epidemiology and treatment of 87 episodes. Annals of Emergency Medicine, 1990;19:1019
- Johnson FC, Okada PJ, Reduction of common joint dislocations and subluxations. King C, Henretig FM: Textbook of Pediatric Emergency Procedures, 2nd ed, Philadelphia, PA, Lippincott Williams and Wilkins, 2007, pp 961- 963