Widespread pressure pain hypersensitivity in elderly subjects with unilateral thumb carpometacarpal osteoarthritis

Widespread pressure hypersensitivity is one of the signs that characterize central pain sensitization in subjects with knee and hip osteoarthritis (OA). The purpose of this study was to evaluate whether widespread pressure pain hyperalgesia is a feature of individuals with unilateral symptomatic thumb carpometacarpal (CMC) OA.A total of 16 patients with unilateral symptomatic thumb CMC OA and 16 healthy sex- and age-matched controls were recruited. Pressure pain thresholds (PPTs) were assessed bilaterally over the first CMC joint; the C5-C6 zygapophyseal joint; the median, ulnar, and radial nerves; and tibialis anterior muscle. Grip and key strength, intensity of pain, and function QuickDASH were also measured.The analyses showed that patients with thumb CMC OA present bilaterally decreased PPTs over the first CMC joint, the C5-C6 zygapophyseal joint, and the tibialis anterior, median, ulnar and radial nerve as compared to controls (all, P < 0.01). Patients with thumb CMC OA also exhibited a bilateral reduction in pinch and grip strength than controls (P < 0.05). A significant correlation was found between PPT over the radial nerve and QuickDASH (r = 0.546, P = 0.029).This study revealed bilateral widespread pressure pain hypersensitivity in individuals with unilateral symptomatic thumb CMC OA, suggesting that central pain processing mechanisms might be a feature of this pain population. These results should be taken into consideration when addressing future treatment approaches.