Can We Really Trust MRI in Diagnosing Knee Injuries in Athletes?

This review discusses the so frequent dilemma for a sports physician or orthopaedic surgeon to stand in front of a professional soccer or rugby player with a knee injury, showing clear clinical signs of a meniscus tear or possibly chondral injury, but with an magnetic resonance imaging (MRI) which has been reported as normal. When arthroscopy finally is undertaken after a lot of discussion and delay caused by the reportedly normal MRI, the clinical suspicion is verified. The opposite situation may of course also occur. A clinician usually refers to MRI when the clinical diagnosis is unclear. However, among professional clubs in the UK the referral to a tertiary specialist is in many cases accompanied with an already undertaken MRI. In this review, we demonstrate several illustrative cases, where MRI has led to unnecessary management delays. The review focuses on meniscus and focal cartilage injuries. We suggest a range of possible solutions, which may improve the situation. There are several controversies to be addressed. First, detailed communication between the clinician and radiologist are often hampered by formal procedures. A referral is sent to the Radiology Department and a radiographer will perform a routine MRI protocol. The referral question may not always point to the correct injury, and is depending on the experience of the clinician. Usually, the radiologist is not present during scanning and instead puts together a protocol and subsequently reports on the images without having seen the injured player. Secondly, the use of different routine protocols for investigation of different structures is often not known in detail by the clinician. Thirdly, there is often a lack of standardized reporting of exact location, size and severity of focal cartilage injury in relation to the patients sporting demands. Furthermore, the quality of healed cartilage in a treated focal defect is of course of vital interest for allowing return to sport. Last but not least, inability to verify dynamic instabilities and structural behaviour during movement of the injured knee decreases the clinical value of MRI when compared with arthroscopy for a number of common sport injuries of the knee.