1. Ten patients with acute slipped capital femoral epiphysis were treated by early gentle manipulation under general anesthesia and followed from two to twentyfour years, or for an average of eleven years. Good results were obtained in all of the nine patients in whom reduction was maintained by two or three partially threaded pins. In the only patient in whom immobilization in a plaster spica was used, there was moderate flattening and cystic change in the lateral portion of the head twenty-four years after reduction, but the functional result was satisfactory.
2. Reduction by early gentle manipulation and extra-articular fixation with two or three partially threaded pins is the preferred method of treatment in acute slipped capital femoral epiphysis.
3. Acute slipping may occasionally be present in the absence of a history of precipitating injury.
4. In the absence of roentgenographic evidence of narrowing of the articularcartilage space, avascular necrosis, or marginal proliferative changes on the femoral head two or three years after operation, a long-term favorable outcome can be anticipated.