Patellofemoral joint abnormalities in athletes: evaluation by kinematic magnetic resonance imaging.

The patellofemoral joint is one of the most common sources of painful symptoms encountered by athletes and is one of the most frequently injured joints. Patellar incongruency is the primary pathologic condition that affects the patellofemoral joint and has been reported to be associated with patellar subluxation, patellar dislocation, chondromalacia, and arthrosis. The diagnosis of patellofemoral incongruency by physical examination alone is extremely difficult because the clinical signs may stimulate other types of internal derangements of the knee, and there is a high incidence of combined abnormalities. In consideration of these issues, a kinematic MRI technique was developed to identify and characterize abnormal anatomic and functional aspects of the patellofemoral joint. Because the patellofemoral joint is often injured in athletes and patellofemoral incongruency is a common site of their pain, this article will discuss the use of kinematic MRI to assess the anatomy and function of the patellofemoral joint, with an emphasis toward special problems that may be found in relation to sports-related activities.