MR imaging findings of lesions involving cartilage and bone in the paediatric knee: a pictorial review.

The knee is the joint which is most commonly imaged by MRI in children and adolescents. With increasing participation in competitive sports, traumatic knee injuries with osteochondral lesions are increasingly common in children. However, it is also important to exclude non traumatic conditions that result in defects of the articular cartilage and/or subchondral bone plate or growth plate of the knee, since timely diagnosis and therapy may help prevent lifelong disability in these patients. Moreover, there are normal variants that occur in the ossifying knee that should not be mistaken for lesions. The aim of this essay is to review the wide range of conditions that may result in MRI signal changes of the ossifying knee in children.