Magnetic Resonance Imaging of the Knee: a Review

In the past 15 years, magnetic resonance imaging (MRI) of the knee has become available as an alternative to diagnostic arthroscopy. MRI has proven to be accurate for the diagnosis of intra- and peri-articular pathology, especially for meniscal pathology (accounting for 86% of the indications for arthroscopy) and ligamentous injuries. It is good enough, especially when using the concept of composite injury (sensitivity of 87.3% and specificity of 88.4%), to appropriately identify patients, who require arthroscopic therapy. In playing this role MRI has diagnostic and therapeutic impact. MRI, when used in all patients with high clinical suspicion of intra-articular knee pathology instead of direct arthroscopy, can avoid 35% of arthroscopies. By influencing the therapy received by a patient, MRI also has the ability to influence patient outcome and societal costs. In patients with sub-acute and chronic knee complaints and with high clinical suspicion of intra-articular knee pathology MRI of the knee can be used to select patients for arthroscopy without additional societal costs and without disadvantageous effect on patient outcome.