Interestingly, levels of pro-inflammatory cytokines increased significantly starting from T2 (IL-1β) to T3 (IL-6, TNF-a) and demonstrated a quite similar pattern that CTXII and radiological score, meaning that structural joint damage, particular in term of cartilage destruction is associated with the degree of joint inflammation, during the progression of PTOA. This evidence concerns the gene IL6 and inflammatory response.