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Assessment of patellofemoral relationships using kinematic MRI: Comparison between qualitative and quantitative methods
Author(s) -
Ward Samuel R.,
Shellock Frank G.,
Terk Michael R.,
Salsich Gretchen B.,
Powers Christopher M.
Publication year - 2002
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.10124
Subject(s) - kinematics , orthodontics , magnetic resonance imaging , quantitative assessment , qualitative analysis , patellofemoral joint , medicine , patella , radiology , qualitative research , physics , social science , classical mechanics , sociology , risk analysis (engineering)
Purpose 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. Results 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. Conclusion 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.