Our findings indicate altered meniscal position and shape (i.e., more bulging) in both compartments in medial compartment knee OA. These changes may be important features of OA pathogenesis and/or disease consequences.

These data suggest a relationship between extrusion of the meniscal body, as measured with quantitative MRI, and knee pain in subjects with knee OA. Further studies need to confirm these findings and their clinical relevance.

The objective of this study was to determine the inter-observer reproducibility (IOR) of quantitative measures of meniscus size and position, and to compare the IOR and agreement between a double echo steady state (DESS) water excitation and an intermediately-weighted turbo spin-echo (IWTSE) sequence. Eight knees (4 healthy, 4 with radiographic knee OA) from the Osteoarthritis Initiative cohort were studied. Manual segmentation of the menisci was performed by 3 observers and quantitative measures of meniscus size and position (i.e. extrusion) computed using image analysis software. The root mean square IOR error (e.g. 5.4% for medial meniscus volume with DESS and 8.4% with IWTSE) was found considerably smaller than the inter-subject variability (average ratio approximately 1:3). The lowest IOR error for meniscus extrusion was obtained for the central 5 coronal slices across the tibial surface. Quantitative meniscus measures from DESS and IWTSE were highly correlated (r=0.71 to 0.99 for the medial meniscus).

Expansile hydrogel devices have led to increased progressive occlusion, while degradable polymer devices led to an increased rate of thrombus organization compared with platinum coils.