Physeal stress injury in youth athletes: upper extremity imaging findings

Sports participation among children predisposes the immature skeleton to unique patterns of injury. In contrast to the mature skeleton, the growth plates of the immature skeleton are biomechanically vulnerable sites of weakness, susceptible to not only acute traumatic but also repetitive overuse injuries. This latter pattern of injury, better known as physeal stress injuries (PSIs), has received increased attention, because undiagnosed and untreated injuries can result in long-term morbidity and risk for future growth disturbance, particularly when involving the physis underlying the epiphysis. This article reviews the anatomy and physiology of the primary epiphyseal growth plate complex, focusing on how injuries centered at the metaphyseal osteochondral junction can disrupt the final step of endochondral ossification. In the second half of this article stereotypical patterns of PSI in three distinct groups of youth athletes are reviewed: the proximal humerus in baseball players, the distal radius in gymnasts, and the phalanges in rock climbers. For each group, sport-specific epidemiologic data, clinical presentation, and characteristic imaging findings are discussed. Multimodality imaging features are discussed, prioritizing the capability of MRI to characterize the spectrum of injury ranging from patterns of ongoing stress to irreversible growth disturbance. By synthesizing the current literature and consolidating imaging characteristics, this article seeks to guide clinicians and radiologists in the timely diagnosis of epiphyseal PSI, ensuring early intervention where treatment is less invasive and often more effective.