Background Knee osteoarthritis (OA) is a common and progressive joint disease with an estimated incidence rate of 240 per 100000 person-years. Pain from Knee OA is generally classified as nociceptive; however, a neuropathic component is possible.
Objectives The objective of this study was to determine the prevalence of neuropathic pain (NP) in patients with painful knee OA using the DN4 questionnaire and to evaluate the relationship between NP, pain intensity, WOMAC function and stage of OA.
Methods We included in this study patients with knee osteoarthritis according to ACR criteria. Pain score using Visual Analogue Scales (VAS), Western Ontario and McMaster Universities Osteo-arthritis Index (WOMAC), DN4 score, duration of symptoms, severity of OA using the Kellgren-Lawrence (KL) system, were evaluated using a Pearson's correlation coefficient. p<0.05 was considered statistically significant.
Results One hundred patients (96 females, 4 males) with a mean±SD age of 59.4±10.4 years were included in the study. Mean±SD duration of symptoms was 72±54 months. The mean ± SD VAS was 5.2±2 and the total WOMAC 50±19. The prevalence of neuropathic pain was 26%. DN4 score was significantly correlated with the VAS (r=0.6, p=0.0001) and the WOMAC (r=0.53, p=0.0001). However, there was no significant correlation between DN4 score and KL grade.
Conclusions DN4 score classified 26% of pain from knee OA as NP. Patients with severe pain and disability may have a NP component in their knee OA pain. It is important to be aware of considering the existence of NP in the treatment of knee OA pain.
Disclosure of Interest None declared