Congenital Radial Head Dislocation
Congenital radial head dislocation is the most common congenital anomaly of the elbow.
It is usually bilateral.
Radial head may be dislocated anteriorly, posteriorly or laterally.
The cause of congenital radial head dislocation is unknown. It occurs sporadically or familial.
Associated anomalies include congenital radioulnar synostosis, Klinefelter syndrome, Cornelia de Lange syndrome, Ehler Danlos syndrome, and Nail patella syndrome.
A delay in presentation is common.
Lack of forearm rotation is unrecognized until the complexities of daily activities amplify such as catching a ball or drinking soup.
The presenting complaints usually involve prominence, restricted elbow movements, and forearm rotation.
Elbow popping or pain with activity is uncommon before adolescence.
The anterior dislocated radial head is palpable just distal to the cubital fossa and may limit full elbow flexion.
The posterior dislocated radial head is palpable and visible lateral to the capitulum. It usually impedes the terminal extension of the elbow.
A diminished forearm rotation, both pronation, and supination are more prominent.
Infants with unossified dislocated radial head may be visualized with diagnostic ultrasound.
In older children, anteroposterior and lateral radiographic view of the elbow is diagnostic.
The radial head fails to align with the capitulum. Other findings include dysplasia of capitulum, abnormal shape of the radial head, and ulnar positive variance.
In childhood, surgical intervention is seldom necessary. Most children are asymptomatic and have minimal functional limitations.
In adolescence or adulthood, a dislocated radial head may become painful due to degenerative changes at the contact point between the radial head and distal humerus.
In such cases, radial head excision reliably relieves pain, improves appearance, and may improve range of motion.
The long term consequences are the restriction of elbow and forearm movements, instability of elbow, and early degeneration of joints.