Epiphyseal Physeal Stress Injury (PSI): An Overview

Year-round participation in youth sport that involves high levels of repetitive movement cultivates an environment in which overuse injuries are likely to occur. Overuse injuries of the epiphyseal primary physis, unique to skeletally immature athletes, are a particular concern given their potential for growth disturbance. Initially observed in Little League baseball players, these injuries are now known to affect the long bones around the shoulder, elbow, wrist, hand, knee, ankle, and foot of skeletally immature athletes involved in a variety of sport activities. This chapter reviews a novel framework for understanding the pathophysiologic mechanisms causing these injuries. Additionally, it provides an epidemiological and radiologic overview on what is known about the extent and distribution of these injuries, including those that progress to growth disturbance.