(A.) Score plot of Principal component analysis on MMP protein expression within the synovial fluid of all samples collected (n = 69). 3 groupings of samples are visible along the axis of component 1, normal control (CTRL) and early OA patients appear grouped together while RA and advanced OA (OA) patients appear to form separate groups. Along the axis of component 2 there is a less distinct separation of treatment groups, however RA and OA appear to be separated with overlap form the normal and early OA. (B.) K-Means clusters to verify the 3 potential groupings of patients. Cluster 1 contains 25 normal, 10 early OA, and 2 OA patients. Cluster 2 contains 14 RA, 2 early OA, and 6 OA patients. Finally, Cluster 3 contains 9 OA and 1 RA patients. (C.) Score plot of Principal component analysis on MMP protein expression within the synovial fluid of only normal and early OA samples.