Figure 2From: Levels of neuropeptide Y in synovial fluid relate to pain in patients with knee osteoarthritis The correlation between synovial fluid NPY concentration and pain of KOA patients. (1 = Healthy control group, 2 = No pain group, 3 = Mild pain group, 4 = Moderate pain group, 5 = Strong pain group, 6 = Severe pain group).Back to article page