Evaluation of patellar cartilage with 3D/WATS/C3f MR imaging and the comparison of the findings with arthroscopy

SUMMARYEVALUATION OF PATELLAR CARTILAGE WITH 3D/WATS/C3f MRIMAGING AND THE COMPARISON OF THE FINDINGS WITHARTHROSCOPYDr. Kartal UlusoyPurpose: To assess the accuracy of 3D/WATS/C3f MR imaging for theevaluation of chondromalacia of the patella.Materials and Methods: Thirty-four patients (34 knees) with pain in the anteriorpart of the knee were prospectively examined with magnetic resonance (MR) imagingand subsequent arthroscopy. Axial images were obtained by using 3D/WATS/C3fMR Imaging (TR: 20 msec, TE: 8 msec, flip angle: 50º, 150 mm field of view, 3 mmthickness, 196 x 256 matrix, NEX: 2) with a 1.5-T MR machine. The sensitivity,specifisity and accuracy of the imaging technique in the diagnosis of each stage ofpatellar chondromalacia were determined and compared by using the Mc Nemar two-tailed analysis.Results: A total of 68 facets were evaluated with MR imaging and arthroscopy.Arthroscopy showed that 42 (61.7%) facets were normal. Sensitivity, specifisity andaccuracy in early grade (grade 1 and 2) of chondromalacia patella were 67% and100%, 81% and 95%, 80% and 96%, respectively. In advanced grade (grade 3 and4), all results for sensitivity, specifisity and accuracy were 100%. There was statisticaldifference only in Grade 1 lesions (p< 0.05). In this group false negative rate andfalse positive rate were 1.4% and 14.7%, respectively.Conclusion: 3D/WATS/C3f MR Imaging of knee revealed higher sensitivity,specifisity and accuracy in the advanced grade of patellar chondromalacia comparedto the early grade. In our opinion, the reason of low sensitivity in Grade 1 lesions wasthe superiority of MR imaging in showing the early changes in the cartilage withoutsurface changes which could not be detected with arthroscopy.