Accelerated fracture union in association with severe head injury.

Union occurred unusually rapidly in 13 fractures of long bones in 11 patients who had sustained severe head injuries. Possible metabolic mechanisms for this are discussed and it is suggested that respiratory alkalosis associated with severe head injury or its treatment affects the rate of deposition of callus by modifying the pH at the fracture site. Fractures in patients with severe head injuries should be restored to an acceptable position early in order to avoid malunion.