Frequency of neuropathic pain and its impact on functional status in primary knee osteoarthritis patients

This is the authors' abstract. We don't add key points for this paper.

Background: Neuropathic mechanisms are considered to play a role in development of pain in knee osteoarthritis (OA). Some OA patients developed sensitized central nociceptive circuits that enhance pain during various states of peripheral tissue insult. Method: 70 patients with primary knee OA were enrolled in this study. Antero-posterior knee radiographs were done using the Kellgren Lawrence scale. Pain severity was assessed by Numerical rating scale (NRS), neuropathic pain was assessed by Douleur Neuropathique en 4 (DN4) questionnaire and functional status was assessed by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scale. Results: 52.9% of the patients had neuropathic pain according to DN4 scale. The mean pain WOMAC score and WOMAC physical function score were significantly higher in patients with neuropathic pain when compared to patients with nonneuropathic pain; 9.86 ± 2.1 versus 6.79 ± 3.59, P <0.0001 and 44.24 ± 5.43 versus 39.39 ± 10.36, P =0.015 respectively. DN4 score had a significant positive correlation with WOMAC pain (r=0.459,P<0.001), stiffness (r=0.258, P=0.031) and physical function (r=0.307, P=0.01). Conclusion: Chronic pain with OA has neuropathic components. Neuropathic pain is a factor that increases pain and disability and disrupts functional status in osteoarthritis patients.