RESUMEN
PURPOSE: To evaluate the efficacy of sagittal fat-suppressed 3D SPGR MR imaging of the osteoarthritic medial femoral condyle in terms of extent and degree of a focal articular cartilage defect of the knee. MATERIALS AND METHODS: The MRI findings (Disler scale) of normal and osteoarthritic medial femoral condyles from 112 knees were prospectively compared with the arthroscopic findings (Jackson staging). The arthroscopic findings were normal in 10 cases, stage I in 26 cases, stage II in 36 cases, stage III in 21 cases and stage IV in 19 cases on arthroscopy. RESULTS: All 10 cases arthroscopy findings were grade 0 in MRI. Among the 26 knees in arthroscopic stage I, only 11 knees (42.3%) showed surface irregularities on MRI that were consistent with grade 1, otherwise grade 2. All cases of arthroscopic stage II showed grade 2 or grade 3. Stage III was grade 3 in all cases on MRI. Among the 19 knees in arthroscopic stage IV, 16 knees (84.2%) with a large defect showed grade 4 on MRI. The sensitivity, specificity and accuracy of the MRI compared with the arthroscopic findings was 97%, 100% and 97.3%, respectively. The weighted kappa index was 0.7194 and the SE (standard error) was 0.053, suggesting significant consistency. CONCLUSION: The sagittal fat-suppressed 3D SPGR MR imaging is valuable for determining the extent and degree of the articular cartilage lesion of the medial femoral condyle in an osteoarthritic knee.