Abstract
Plain films are adequate for most cases of uncomplicated arthropathies and trauma. For suspected internal derangement, MRI is the optimum technique. Routine plain films are not indicated. Ultrasound is ideal for initial examination of periarticular swellings and tendon disorders. MRI or CT arthrography is the best method for assessing the post-operative meniscus. Imaging plays a major role in the management of knee disorders. In acute trauma with suspected internal derangement, MRI is an excellent technique for differentiating cases of true locking requiring arthroscopy from non-surgical cases. MRI is nearly always diagnostic for acute patellar dislocation. In chronic knee disorders, MRI is also shown to be sensitive and specific for a wide range of meniscal, ligamentous, bony and synovial pathologies. Plain films are rarely needed in addition to MRI, and should be generally reserved for suspected osteoarthritis and acute bony trauma. Ultrasound is a useful and cheap first-line investigation for soft-tissue masses and tendon pathology. Imaging, including MRI dynamic studies, is useful in the assessment of the common problem of anterior knee pain. In the post-operative knee, MRI is still useful but less accurate. MR arthrography and CT arthrography are useful for assessing the post-surgical meniscus.