Patellofemoral joint: evaluation during active flexion with ultrafast spoiled GRASS MR imaging.

An ultrafast spoiled gradient-recalled acquisition in the steady state pulse sequence was developed that permits multiple images to be obtained at a temporal resolution suitable for examining the patellofemoral joint during active flexion. This pulse sequence was used to perform kinematic magnetic resonance imaging of patellar alignment and tracking in five healthy subjects and seven patients with a provisional clinical diagnosis of abnormal patellofemoral joints.