Quantification of patellar tracking using kinematic MRI

✍ Scribed by Christopher M. Powers; Frank G. Shellock; Martin Pfaff

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 971 KB
• Volume: 8
• Category: Article
• ISSN: 1053-1807
• DOI: 10.1002/jmri.1880080332

✦ Synopsis

Abstract

The purpose of this study was to describe a method to quantify dynamic patellar tracking using kinematic MRI (KMRI). Twelve normal females and three patients with patellofemoral pain participated. Imaging was performed with a 1.5‐T/64‐MHz MR system using a fast spoiled gradient‐recalled acquisition in the steady state (GRASS) pulse sequence. A nonferromagnetic positioning device permitted active, bilateral knee extension against resistance (15% bwt) from 45° knee flexion to full extension. Subjects were instructed to extend their knees at a rate of 9° per second, which allowed images to be obtained at 45°, 36°, 27°, 18°, 9°, and 0°. All images were assessed for medial/lateral patellar displacement, patellar tilt, and sulcus angle using a computer‐aided system. Normal patellar motion was characterized by medial movement from 45° to 18°, followed by a reversal toward lateral displacement from 18° to full extension. The results for patellar tilt revealed a tendency toward decreasing lateral tilt as the knee extended. Sulcus angle measurements indicated that the patella was moving to a more shallow portion of the trochlear groove (superiorly) during extension.