[Magnetic resonance arthrography indications and technique (II). Lower limb]

Magnetic resonance (MR) is the imaging technique of election in the evaluation of the articular pathology. MR arthrography (MRA) consists of the direct punction of the joint with intraarticular injection of diluted gadolinium or saline solution. MRA produces distention of the capsular recess, delineates the intraarticular structures and separates annexed structures of difficult evaluation, with which it is able to improve the reliability diagnoses of the articular and periarticular pathology. MRA allows to solve some of the diagnostic problems of conventional MR imaging in the evaluation of the articular pathology, avoiding to make unnecessary diagnostic arthroscopy and allowing a better therapeutic plan. In the greater joints of the inferior extremity (hip, knee and ankle) MRA has established indications standing out the evaluation of the injuries of the acetabular labrum of the hip, the operated meniscus of the knee and the study of the "impingement" syndromes of the ankle. This article reviews the present utility of the MRA in the hip, knee and ankle joints. The more relevant anatomical aspects, the technique and the applications are reviewed. Finally, the value of this technique in pathologies that can affect any joint of the organism such as osteochondral injuries, loose intraarticular bodies and synovial pathology is reviewed.