with more severe disturbance of the epiphysis on radiographs have a poorer prognosis ANNULAR LIGAMENT DISPLACEMENT (RADIAL HEAD SUBLUXATION) Current Evidence “Nursemaid’s elbow” is the most common joint injury in pediatric patients, usually occurring in children between months and years of age The term annular ligament displacement (ALD) is replacing radial head subluxation for this entity because it is more anatomically correct Displacement of the annular ligament occurs as a result of traction on a pronated hand or wrist, causing the ligament to slide over the radial head and become interposed between the radius and capitellum The absence of a history of traction on the arm in children with ALD suggests there may be alternative mechanisms Except for a very slight increase in the distance between the radial head and capitellum that can be seen on ultrasound, the relationship between radial head and capitellum remains essentially unchanged, and radiographs are normal in patients with ALD The radial head is not abnormal and the annular ligament does not necessarily tear when this injury occurs The left elbow is more often affected because adult caregivers tend to hold the child’s left hand with their dominant right hand Clinical Considerations Clinical Recognition ALD can be strongly suspected from across the examining room The child generally holds the arm slightly flexed, against his or her body with the forearm pronated When left alone, the child does not appear to be in significant pain Parents may report a problem with the wrist or shoulder because, in their attempts to assess these joints, inadvertent movement of the elbow causes pain Physicians can be similarly fooled, especially when a classic history of traction is not obtained Initial Assessment/H&P In up to half of the cases, a history of traction on the arm is not obtained, which may suggest another mechanism for this injury or perhaps caregivers who are reluctant to volunteer self-incriminating information Astute clinicians should suspect this injury even in the absence of the typical history