Patellofemoral joint: kinematic MR imaging to assess tracking abnormalities.

Abstract
The patellofemoral joint was imaged with magnetic resonance (MR) in the axial plane while the knee was positioned from 0.degree. to 32.degree. of flexion (nine positions). These multiple sequential images obtained within the early phases of flexion of the knee were viewed in a "cine-loop" format, producing a kinematic study that clearly demonstrated the relationships of the patella to the trochlear groove. Four healthy subjects and one patient with known bilateral subluxing patellae were studied. The preliminary results suggest that kinematic MR imaging of the patellofemoral joint is potentially useful for the evaluation of patellar tracking abnormalities.