Focal periphyseal edema (FOPE) revisited: does injury severity predict presence and frequency of FOPE lesions?

Background Focal periphyseal edema (FOPE) is a MRI finding identified in long bones in children nearing skeletal maturity. Existing literature is conflicting, with the majority suggesting that FOPEs are potential pain generators related to supraphysiologic sporting activities and some reports suggesting that FOPE’s represent normal physiologic physeal maturation. Objective The purpose of this study is to investigate the incidence of knee FOPE lesions in adolescent boys with ACL tears compared with a negative cohort. Materials and methods 104 knee MRI’s with ACL tears and 108 normal knee MRI records between the ages of 12 to 15 were identified from a major children’s hospital. These MRIs were then randomized and reviewed in consensus by two pediatric MSK radiologists for location and number of FOPE lesions in the proximal tibia and distal femur. Results There is no statistical difference between the presence of FOPE in the ACL tear cohort compared with our negative control (40% vs 41%) ( p  = 0.913). When comparing the location of lesions in the proximal tibia vs the distal femur between ACL tear group and control group, there is no statistical difference ( p  = 0.906). A transphyseal vessel was identified in 47% of all FOPE lesions, independent of ACL tear status. Conclusion The results of this study reinforce the idea that FOPE is a frequent incidental finding in adolescent knee MRIs, irrespective of predisposing supraphysiologic activity. Our findings question previous reports that suggest FOPE lesions are associated with supraphysiologic stress. FOPE lesions are frequently associated with transphyseal vessels.