How Common Is Recurrent Radial Head Subluxation?

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Patient Presentation
A 3-year-old male came to clinic who was not using his arm after playing with his older sister about 2 hours previously. She said that she had been pulling on his left arm and then he cried and stopped moving it. The grandmother who had been taking care of the child brought the child to clinic. The parent provided history by phone and noted that the boy had had radial head subluxation of the same elbow about 10 months previously and it had been reduced in the urgent care setting. He had been normal between the 2 events. The grandmother noted that he complained of pain when putting on and taking off his jacket when coming to the clinic.

The pertinent physical exam showed an unhappy child with normal vital signs and growth parameters around the 50%. He was holding his left arm with his elbow flexed and slightly pronated and close to his body. He denied any pain with actual palpation of the arm from shoulder to fingers. There was normal range of motion in the shoulder, wrist and fingers. The child was refusing to move the arm, but then spontaneously extended the elbow to reach for a toy.

The diagnosis of a recurrent radial head subluxation was made and the physician did not feel given the mechanism, history and physical examination that radiographs were necessary at this time. After discussion with the grandmother, the physician performed a closed reduction maneuver with elbow supination and flexion. No “pop” was felt or heard, and the patient winced and pulled away. However, the patient began to spontaneously move the elbow in the room while playing with his sister as the physician was giving followup instructions to the grandmother. He also easily put on his coat without obvious pain before leaving.

Discussion
Radial head subluxation (RHS) is most commonly occurs in children 6 months – 4 years old. It occurs because of the anatomy and child development. The radius is connected to the ulna just distal to the radial head by an annular ligament that encircles the radius “neck” (i.e. radial diaphysis) and inserts into the ulnar tuberosity. However the annular ligament is relatively small and also not as fibrous in young children compared to older children and adults. Young children often have their arm extended upward to hold hands with an adult especially when they are new walkers. If the child stumbles or for some other reason has the adult place traction (i.e. pull the extended arm) on the arm, the radial head can be subluxed distally and become entrapped in the ligament. The common name is nursemaid’s elbow for this reason. The child may cry in pain or not, but refuses to use the arm, especially the elbow, properly. The adult also may be unaware of what has happened since the incident doesn’t appear to have any significant trauma associated to it. This pulling mechanism is not universal and many times the cause may be something else (e.g. fall, hit, swinging, lifting, car seat, dressing, etc.) that is witnessed or often goes unwitnessed by an adult. There is a slight increase incidence in females than males and left elbow is more commonly affected than right. It is thought that as more adults are right handed that they tend to hold the left arm of the child and therefore this arm is more at risk.

Elbow trauma can be complicated because of the multiple bones, ossification centers, and multiple ligaments of the joint. A review of the ossification centers can be found here. If there is any concern for significant trauma including potential fracture, the elbow should be stablized and radiographs obtained, before attempting RHS reduction maneuvers. A review of the reduction methods for RHS can be found here Unfortunately, the elbow is the most commonly dislocated joint and can have chronic instability although this is usually due to more significant trauma. Dislocations occurring with the radial head and fracture of the coronoid process are termed the terrible triad as they are so difficult to treat and often have acute or chronic instability. If there is a fracture or it is unclear if there is a fracture, then the elbow should be stabilized and orthopaedics consulted.

Learning Point
RHS can commonly recur. Those that recur are more likely to be male (possibly because of increased physicality), and younger (probably because this is the age when it occurs and because they have a longer time within the risk age range).

In one study from 2016 in the emergency room with a total of 246 visits for RHS, they had 47 visits (19%) in 18 patients for recurrent RHS (RRHS). Of the 18, 10 patients had 1 visit, 7 had 3 visits and 1 had 5 visits. In another study from 2019 also in pediatric clinics and the emergency room of 9827 patients, of these a total of 1195 had RRHS for an overall relapse rate of 12.2%. Most (N=76%) had one relapse, 17.8% had 2 relapses, 4.4% had 3 relapses, 0.9% had 4 relapses and 0.4% had 5 relapses. They also note that one patient had bilateral RHS and had a relapse in each arm. These studies noted that recurrence does not appear to occur after age 7, probably because of the anatomical changes. Note, that the actual RRHS rates could easily be higher with studies from 30-50 years ago noting up to 39%. Once RHS occurs, parents are counseled about the problem and may be counseled on when and how to potentially complete a closed reduction at home, thereby negating a clinic or emergency room visit. Also even during the first occurrence, some patients will also self-reduce and therefore will not come to clinic because they have improved.

Questions for Further Discussion
1. What is the usual position of the elbow when presenting for RHS?
2. What are indications for referral to orthopaedics for RRHS?
3. What are indications for radiographic imaging for elbow problems?

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com, and the Cochrane Database of Systematic Reviews.

Information prescriptions for patients can be found at MedlinePlus for this topic: Elbow Injuries and Disorders.

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

Tashjian RZ, Katarincic JA. Complex Elbow Instability. J Am Acad Orthop Surg. 2006;14(5).

Wong K, Troncoso AB, Calello DP, Salo D, Fiesseler F. Radial Head Subluxation: Factors Associated with Its Recurrence and Radiographic Evaluation in a Tertiary Pediatric Emergency Department. J Emerg Med. 2016;51(6):621-627. doi:10.1016/j.jemermed.2016.07.081

Wang YX, Zhang G, Song B, Li M. Radial head subluxation in pediatric clinics and emergency departments in China. Chin J Traumatol. 2019;22(6):340-344. doi:10.1016/j.cjtee.2019.08.004

Author
Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa

Published