1. Lower humeral epiphysiolysis with dislocation of the epiphysis (of the capitellum and trochlea, or of the capitellar portion alone) is a relatively common injury in the first decade of life.
2. This compression injury is sustained by direct violence,—falling on the flexed elbow.
3. As the epiphysis separates and the force continues, the capitellar epiphysis is forced through the anterior capsule and dislocation occurs. The capitellar epiphysis alone may separate, or the capitellum with the trochlear epiphysis may subluxate.
4. Closed reduction may occasionally be successful. Reduction when incomplete is followed by extreme loss of function; therefore, operative reduction is warranted in every case in which reduction by manipulative methods is incomplete.