Detection and staging of patellar cartilage lesions with MR imaging: Pathologic correlations

Fourteen freshly disarticulated knee specimens were studied to assess the ability of MR imaging to enable detection and accurate staging of patellar chondral lesions. Axial and sagittal images were obtained; T1-weighted pulse sequences were found satisfactory for defining cartilage morphology. Specimens were sectioned and examined grossly for cartilage changes such as softening, blistering, fibrillation, fissuring, and frank subchondral bone exposure. In a side-by-side comparison, all lesions classified grossly as grade II (Outerbridge) or higher were demonstrated by MR imaging. Grade I changes could not be identified in disarticulated specimens. MR imaging enable accurate detection and staging of moderate and advanced patellar cartilage lesions