The knee: MR imaging of uniquely pediatric disorders

The knee is one of the joints most commonly injured during sport-related activities in the pediatric population. Although physical examination and conventional radiography remain the most important tools for determining the extent of the injury, clinical assessment of the knee may be limited in patients with pain, swelling, and effusion, and conventional radiology may overlook serious injuries. MR imaging is an excellent modality for pediatric knee disorders given its lack of ionizing radiation, multiplanar capabilities, and high resolution, which provides accurate assessment of bone, cartilage, menisci, ligaments, and adjacent soft tissues. This article describes MR imaging findings of unique disorders of the pediatric knee, common traumatic injuries, frequent developmental abnormalities, and benign incidental findings.