Increased movement pain in osteoarthritis of the hands is associated with Aβ-mediated cutaneous mechanical sensitivity

The relationship between joint pain and hyperalgesia has been explored in animal models of articular inflammation, but is yet to be shown in the most common rheumatologic condition: osteoarthritis. In this study, cutaneous thermal and mechanical pain thresholds were measured over the thumb of patients with osteoarthritis of the hands. In symptomatic patients, pain was manipulated through resisted active movement of the thumb. Provocation of movement pain (MP) was associated with a sustained fall in mechanical pain thresholds. Thermal pain thresholds remained stable during increases in joint pain. Increased mechanical sensitivity after exacerbation of MP was alleviated by Aβ fiber blockade. It appears that superficial tenderness over the osteoarthritic thumb fluctuates with pain arising from movement of the joint. It is concluded that dorsal horn mechanisms contribute to MP-related hyperalgesia in osteoarthritis of the hands.