Technical improvements of MRI have significantly improved the visualization of joints. New sequences and experience with MRI has lead to increased sensitivity and specificity of internal joint lesions. For the first time, contusions of the subchondral bone which are prognostically significant for the developing of chondral lesions can be identified. To date, no other tests are available to identify such lesions. This review article outlines the current value of MRI for evaluating post-traumatic knee joint injuries.