Imaging of the knee.

MR imaging has become the primary imaging modality of the knee. Its advantages include its noninvasive nature, multiplanar imaging capability, excellent soft-tissue contrast, and high resolution. The need for multiple imaging modalities is obviated, as the menisci, cruciate ligaments, synovium, articular cartilage, marrow, and periarticular soft tissues can be simultaneously evaluated. Other imaging modalities may occasionally be helpful in the evaluation of specific problems including CT in tibial plateau fractures, real-time ultrasound for the confirmation of a popliteal cyst or popliteal artery aneurysm, and arthrography for the detection of prosthetic joint loosening.