Clinical phenotypes of neuropathic pain and central sensitization in patients with knee osteoarthritis: demographic data, radiographic severity, and pain intensity.

BACKGROUND: We aimed to simultaneously assess neuropathic pain (NP) and central sensitization (CS) in patients with knee osteoarthritis to determine their prevalence and identify patient characteristics associated with NP and CS based on demographic data, pain intensity, and radiographic severity commonly assessed in routine clinical practice. METHODS: Patients with knee osteoarthritis (136) were evaluated. NP was assessed using the painDETECT questionnaire, with scores ≥ 13 categorized as NP( +). CS was assessed using the Central Sensitization Inventory (CSI), with scores ≥ 30 classified as CS( +). Pain intensity was measured at rest and during exercise using the visual analogue scale. Patients were grouped into low-pain and high-pain categories based on the average visual analogue scale score of pain at rest. Radiographic severity was assessed using the Kellgren-Lawrence grading system, classifying patients into low-grade (II–III) and high-grade (IV) categories. Demographic data, pain intensity, radiographic severity, painDETECT, and CSI scores were compared between the low- and high-pain intensity, low- and high-grade severity, NP( +) and NP( −), and CS( +) and CS( −) groups. RESULTS: NP and CS were identified in 15.4% and 16.2% of patients, respectively, and either NP or CS mechanisms were observed in 25.6%. CSI scores were higher in the high-pain group, and pain at rest was significantly higher in NP( +) and CS( +) groups. CONCLUSIONS: Either NP or CS mechanisms were identified in 25.6% of patients with knee OA. Higher pain at rest was associated with NP and CS, particularly CS, in this cohort.