“Starburst” Edema of the Closing Distal Femoral Physis: A New Explanation for Adolescent Knee Pain

The goals of this study are (1) to introduce the MRI phenomenon of "FOPE" -- focal periphyseal edema -- to the orthopaedic community and (2) to describe the characteristic features, natural history, and clinical outcomes of a series of athletic adolescent patients presenting with atraumatic knee pain and MRI-demonstrated periphyseal edema. This is an IRB-approved retrospective chart review of five skeletally immature adolescent patients who presented for evaluation of activity-related knee pain. Each patient was evaluated by a fellowship-trained pediatric orthopaedist and subsequently underwent noncontrast MRI evaluation of the affected joint. Patients selected for inclusion in this study had a "starburst" pattern of edema surrounding the closing growth plate on T2 MR imaging. Exclusion criteria included skeletal maturity and a history of traumatic knee injury. Patient age, sex, presenting symptoms, physical exam findings and treatment plans were extracted from each chart.