A subluxation is a partial dislocation, so patients with Nursemaidâs elbow have a partial dislocation of head of the radius. The head of the radius normally articulates with the lateral side of the humerus at the capitulum, and is held in place with the radial notch of the ulna by the annular ligament. Particularly in children, if the hand is pulled on with enough force, it can cause the head of the radius to be displaced underneath the annular ligament, resulting in the inability to supinate the arm and experience pain.
If a patient with Nursemaidâs elbow is standing in anatomical position, the proximal head of the radius will be inferiorly displaced, or âbelowâ the annular ligament. It is also not uncommon for the radial head to be subluxed (partially dislocated) downward, and then for the radial head to move to the side (laterally) next to the annular ligament, resulting in a subluxation and a dislocation.
Axial traction refers to outward movement away from the body. Any type of pulling force on the hand or distal arm, such as forcefully tugging a childâs hand, may cause this injury.
Any type of pulling force on the distal arm, such as pulling a child up by the hands, forcefully pulling or jerking a childâs hand, or playfully swinging the child by their arms, may cause this injury.
This injury occurs most commonly in children of preschool age, which is usually one to four years old. Older children are at a decreased risk because their joints, and the ligaments surrounding them are stronger, and older children are less likely to be in a situation where this injury might occur.
Radial articulation with the humerus allows for forearm supination and flexion; thus, when the radial head is displaced, the child will be unable to perform these motions, and their arm will be extended and pronated.
Bending of the elbow may generate pain, so patients may hold their arm to their side. However, nursemaidâs elbow does not commonly cause localized swelling or deformity unlike other forms of trauma to the elbow joint.
There are two techniques that can be performed by a provider to manually reduce the dislocated joint: supination of the elbow at 90 degrees flexion and hyperpronation of the forearm.
While applying direct pressure with one finger on one hand on the radial head, the provider grips the childâs forearm with his other hand, and hyperpronates the forearm until the radial head clicks back into place.
Using the thumb on one hand to hold the elbow and apply pressure on the radial head, the provider then supinates the patientâs hand and forearm, and then flexes the elbow to 90 degrees. This supination, followed by 90 degree flexion, aims to guide the radial head back in the annular ligament in its proper position.
If nursemaidâs elbow can be successfully reduced, further treatment is not needed. The child often experiences immediate pain relief after manual reduction, and normal activity can be resumed shortly after.
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