Patellofemoral joint motion: evaluation by ultrafast computed tomography.

Patellofemoral maltracking is a recognized cause of peripatellar pain. Measurements of the patellofemoral relationships during active motion are not available, and clinicians currently rely on observation, palpation, and static radiographic images to evaluate the symptomatic patient. Ultrafast computed tomography (ultrafast CT) offers objective observations of the dynamic influences of muscle contraction on the patellofemoral joint as the knee is actively moved through a range of motion from 90 degrees flexion to full extension. This study reports our initial observations and establishes a range of normal values so that patients with a clinical suspicion of patellar maltracking may be evaluated.