Neuropathic pain in Egyptian patients with primary knee osteoarthritis: Relationship with functional status and radiological severity

Abstract

Aim of the workThe present study was conducted to identify the frequency of neuropathic pain (NP) and its relationship with functional status and radiological severity in a series of Egyptian patients with primary knee osteoarthritis (OA). Patients and methodsThe study included 165 patients with primary KOA. Visual analogue scale (VAS)-pain was estimated and the Western Ontario and McMaster (WOMAC) Universities osteoarthritis index was used for assessment of pain, stiffness and physical function, Douleur Neuropathique in 4 questions (DN4) questionnaire was used to assess NP and Kellgren-Lawrence (KL) radiological grading was used to assess OA severity. ResultsThe mean age of the patients was 53.08 ± 6.95 years, were 144 females and 21 males, 23 were employed, body mass index was 24.87 ± 1.91 and total WOMAC was 44.24 ± 16.52. The mean DN4 score was 2.81 ± 1.27. 29 (17.6%) patients had NP. The mean symptom duration was significantly longer in patients with NP (50.9 ± 14.58 months) compared to those without (36.53 ± 25.25 months) (p = 0.008). The VAS-pain and WOMAC score were significantly increased in patients with NP compared to those without (p < 0.001) while the KL was comparable. The DN4 questionnaire significantly correlated with VAS-pain at rest (r = 0.56, p = 0.002); and with WOMAC pain subscale (r = 0.38, p = 0.043). ConclusionA relevant proportion of KOA patients have NP and is remarkably related to the disease duration. Functional capacity is adversely affected in these patients. However, no relation was found between DN4 questionnaire and the radiological severity. Once detected, suitable treatment options for NP should be included in the management of primary KOA.