Topical Nigella Sativa oil versus diclofenac gel for knee osteoarthritis: A randomized open-labeled active-controlled clinical trial

Osteoarthritis (OA) is the most common cause of pain and disability among older adults. This study aims to compare the effect of topical use of Nigella Sativa (NS) oil and diclofenac gel on pain and function in knee OA (KOA). This randomized clinical trial was performed in a rheumatology clinic. Patients who fulfilled the American College of Rheumatology criteria for OA were selected. The subjects were randomly assigned to apply NS oil or diclofenac gel on the knee joint 4 times a day for 3 weeks. The outcomes, including pain and physical activity, were measured with a visual analog scale and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Of the initial 200 KOA patients who were assessed for eligibility, data from 60 patients (30 in each group) were analyzed. The two groups had no significant difference regarding age, sex, and body mass index. Both interventions showed statistically significant within-group differences in terms of the WOMAC subscales of pain, stiffness, function and VAS of pain (P < 0.001). However, there was no significant difference between the groups. Our findings suggested that topical use of NS oil could be as effective as diclofenac gel in reducing pain and stiffness and improving function in KOA.