Neuropathic-like symptoms and central sensitization related signs and symptoms negatively affect the functional performance of patients with knee osteoarthritis - a cross-sectional study

Objective: This study aimed to compare the functional performance among participants with a neuropathic-like symptoms (NS) and central sensitization related signs and symptoms (CS), and their knee osteoarthritis (OA) counterparts. Methods: A cross-sectional observational study was conducted with 125 participants with knee OA (94 females, mean age 63.1 +/- 7.4 years). Participants completed a self-reported questionnaire with personal and clinical features and musculoskeletal pain characteristics, including NS (PainDETECT), CS (Central Sensitization Inventory, CSI), and conditioned pain modulation. Self-reported functional disability (Western Ontario and McMaster Universities Osteoarthritis Index, WOMAC) and functional mobility (Timed Up and Go, TUG) were compared among patients with NS, CS, and their knee OA counterparts using the one-way analysis of variance (ANOVA). Results: Thirty-three (26.4%) participants had NS and CS, eighteen (14.4%) had NS, twenty-seven (21.6%) participants had CS, and 47 (37.6%) had knee OA with no NS or CS. A one-way ANOVA revealed greater functional limitation in the group with NS and CS (mean = 67.5 +/- 12.0) or NS (mean = 56.7 +/- 17.5) than the group without these symptoms (mean = 32.0 +/- 20.7) with a statistical significance difference [F(3, 121) = 29.434, p < 0.001] in the WOMAC Total score. The group with NS and CS (mean = 19.2 +/- 7.4) or NS (mean = 16.3 +/- 6.3) had slower velocity than the group without these symptoms (mean = 11.6 +/- 3.5) with a statistical significance difference [F(3,121) = 10.045, p < 0.001] in the TUG test. Conclusion: Participants with knee osteoarthritis and NS or CS pain phenotype have greater functional limitations than their counterparts.