Assessment of patellofemoral relationships using kinematic MRI: Comparison between qualitative and quantitative methods
Article first published online: 26 JUN 2002
Copyright © 2002 Wiley-Liss, Inc.
Journal of Magnetic Resonance Imaging
Volume 16, Issue 1, pages 69–74, July 2002
How to Cite
Ward, S. R., Shellock, F. G., Terk, M. R., Salsich, G. B. and Powers, C. M. (2002), Assessment of patellofemoral relationships using kinematic MRI: Comparison between qualitative and quantitative methods. J. Magn. Reson. Imaging, 16: 69–74. doi: 10.1002/jmri.10124
- Issue published online: 26 JUN 2002
- Article first published online: 26 JUN 2002
- Manuscript Accepted: 19 MAR 2002
- Manuscript Received: 14 NOV 2001
- magnetic resonance imaging;
- patellofemoral joint;
To compare the level of agreement between quantitative and qualitative methods in determining patellofemoral relationships, since controversy exists regarding the use of quantitative vs. qualitative criteria to interpret images of the patellofemoral joint (PFJ) obtained using kinematic magnetic resonance (MR) imaging.
Materials and Methods
One hundred twenty mid-patellar axial plane images obtained using kinematic MR imaging from fifteen subjects were randomly selected for analysis. MR images represented various knee flexion angles ranging from 0 to 60 degrees. Quantitative analysis (bisect offset and patellar tilt angle) was performed by two examiners using a computer-assisted software program. Based on data from previously published literature, MR images were characterized as demonstrating normal, medial, or lateral patellar subluxation, and/or normal, medial, or lateral tilt. Using similar categories, two different examiners experienced in reading MR images of the PFJ then applied qualitative criteria to the same images.
The average agreement between the quantitative and qualitative assessments of horizontal patellar displacement and patellar tilt ranged from poor to moderate (Kappa coefficient values of 0.27 and 0.45, respectively). Quantitative and qualitative techniques demonstrated acceptable intra- and inter-observer reliability.
These findings indicate that the use of quantitative criteria does not compare well to qualitative criteriain the analysis of kinematic MR images of the PFJ. One explanation for this discrepancy relates to the fundamental difference between the techniques. That is, quantitative measurements are based on the use of osseous landmarks, while the qualitative assessments tend to rely on a description of patellofemoral relationships based on joint surfaces. J. Magn. Reson. Imaging 2002;16:69–74. © 2002 Wiley-Liss, Inc.