Patellofemoral Instability: Evaluation by Magnetic Resonance Imaging.

Objective: To determine the contribution of magnetic resonance imaging (MRI) in evaluating patelofemoral instability.

Methods: 39 patients (45 knees) with patellar instability underwent knee magnetic resonance images between October 2009 and July 2011, at the Rede Lab's D'Or, in the city of Rio de Janeiro, State of Rio de Janeiro, were included. MRI were analyzed for the presence of bone, hyaline cartilage and soft-tissue abnormalities, as well as anatomic variants that may contribute to chronic patellar instability.