Knee Osteoarthritis (OA) lead to chronic disability in the older population. Latest evidence revealed that oxidative stress is one of the triggering factors of OA. It was hypothesised that a sustained duration of vitamin E administration would reduce the oxidative stress, inflammatory process and develop symptoms in patients with end-stage knee OA. Consequently, this study was done with the purpose to assess the antioxidative and anti-inflammatory impacts of Vit. E on oxidative stress in the plasma, synovial tissue and synovial fluid of subjects with knee osteoarthritis.

This randomised controlled study enrolled 72 patients who were at late-stage knee osteoarthritis planned for total knee arthroplasty. They were randomised and provided with either oral placebo (Group A) or 400 IU of vitamin E (Group B) once a day for two months before undergoing surgery. Specific parameters were compared before and after the intervention between the two groups. These are like blood levels of endpoints indicating oxidative stress or antioxidant capacity, Knee Society Score (KSS), Western Ontario and McMaster Universities Osteoarthritis Index score (WOMAC), and adverse effects. At surgery, these redox endpoints and histological findings were compared between the synovial fluid and synovial tissue. It was found that in blood samples, the pre-intervention of oxidative stress and antioxidative capacity were not altered between Group A and Group B. In post-intervention blood samples, the Malondialdehyde (Group A 1.34 ± 0.10, Group B 1.00 ± 0.09, p < 0.02), Alpha-tocopherol (Group A 15.92 ± 1.08, Group B 24.65 ± 1.47, p < 0.01) and Trolox equivalent antioxidant capacity (Group A 4.22 ± 0.10, Group B 5.04 ± 0.10, 0 < 0.01) were significantly varied between Group A and Group B. In synovial fluid samples, the Malondialdehyde (Group A 1.42 ± 0.12, Group B 1.06 ± 1.08, p 0.01), Alpha-tocopherol (Group A 4.51, Group B 7.03, p < 0.01), Trolox equivalent antioxidant capacity (Group A, 1.89 ± 0.06, Group B 2.19 ± 0.10) were significantly varied between Group A and Group B. The pre-intervention WOMAC score and KSS score were not different between Group A and Group B. The post-intervention WOMAC score was significantly increased in all categories in Group B (Pain: Group A 27.26 ± 0.89, Group B 19.19 ± 1.43, p < 0.01; Stiffness: Group A 8.23 ± 0.79, Group B 5.45 ± 0.73, p 0.01; Function: Group A 94.77 ± 4.22, Group B 72.74 ± 6.55, p < 0.01). The post-intervention KSS score was significantly increased in all categories in Group B (Clinical: Group A 25.31 ± 14.33, Group B 33.52 ± 16.96, p < 0.01; Functional: Group A 41.43 ± 16.11, Group B 51.6 ± 19.60, p<0.02). Significantly fewer synovial tissue cells were stained with nitrotyrosine and hematoxylin-eosin in Group B than in Group A. There were no variations in adverse effects or surgical complications between the groups.

It was demonstrated that in patients with late-stage knee osteoarthritis, Vitamin E is an effective antioxidant that can improve clinical symptoms and lower oxidative stress conditions.