Impact of neuropathic symptoms and signs and symptoms of central sensitization on functionality of patients with knee osteoarthritis - cross-sectional study

Abstract

Introduction: Knee Osteoarthritis (OA) is one of the leading causes of disability in the elderly. OA pain has nociceptive and neuropathic mechanisms at the local and central levels. However, the impact of neuropathic pain or central sensitization on functional performance of patients with knee OA is unclear. Methods: A cross-sectional observational study with participants aged 50 and over, diagnosed with knee OA were conducted. Participants filled a self-reported questionnaire including clinical history,
sociodemographic variables, and musculoskeletal pain characteristics. Neuropathic pain (PainDETECT), symptoms of central sensitization (Central Sensitization Inventory, CSI), conditioned pain modulation (Cold Pressor Test, CPT), self-reported functional disability (Western Ontario and McMaster Universities Osteoarthritis Index, WOMAC), and functional mobility (Timed Up and Go, TUG) were also investigated. The comparison of functional performance among patients with a neuropathic component, sign and symptoms of CS, and their knee OA counterparts was performed using the one-way ANOVA. Results: Thirty-three (26.4%) participants had NP and CS, eighteen (14.4%) had NP, twenty-seven (21.6%) participants had CS, and 47 (37.6%) had knee OA with no NP or CS. A one-way ANOVA revealed greater functional limitation in the group with NP and CS (mean = 67.5, SD = 12.0) or NP (mean = 56.7, SD = 17.5) than the group without these symptoms (mean = 32.0, SD = 20.7) with a statistical significance difference [F(3, 121) = 29.434, p < 0.001] in the WOMAC Total score. The group with NP and CS (mean = 19.2, SD = 7.4) or NP (mean = 16.3, SD = 6.3) had slower velocity than the group without these symptoms (mean = 11.6, SD = 3.5) with a statistical significance difference [F(3,121) = 10.045, p < 0.001] in the TUG test. Participants with CS without NP had significantly higher self-reported functional limitation measured by the WOMAC but a non-significant difference in the speed during the TUG test than those with knee OA without neuropathic or central component. Discussion: Neuropathic components and signs and symptoms of CS impact the functionality of patients with knee. Measuring the factors that affect the functionality in patients waiting for knee replacement may contribute to assertive decision-making. Conclusion: Participants with knee osteoarthritis and neuropathic symptoms or central pain phenotype have greater functional limitations compared to their counterparts.