Background The use of hyaluronic acid in the form of intraarticular injections in the treatment of the patients with primary osteoarthritis (OA) of the knee leads to a rapid and time-limited effect of reducing pain and increase of joint function, and also to a functional improvement of patients.
Objectives The aim of this study was to compare the efficacy of treatment with viscosupplementation in patients with rheumatoid arthritis (RA) and secondary OA of the knee with the efficacy of the viscosupplementation therapy in patients with primary OA of the knee.
Methods The study included 44 OA patients with similar demographic (age, sex, BMI) and clinical characteristics (duration of disease, bilateral or unilateral gonarthrosis in II and III stage according to Kellgren Lawrence criteria) divided into two groups. First group included 22 patients with RA and secondary OA of the knee, in the second group were 22 patients with primary OA of knee. All patients received three intraarticular injections of hyaluronic acid of high concentration and high molecular weight, a total of 90 mg in one knee. To evaluate the effectiveness of treatment we observed severity of knee pain on visual analogue scale VAS 0-100mm, functional status of the patient through patient’s assessment of the ability to walk (VAS 0-100mm), and clinical findings of knee motion limitation through Lickert scale (0-3) before treatment, after 6, 12 and 18 months. For statistical analysis, Student t-test and Fischer test were used.
Results The severity of pain in the first group of patients was significantly lower 6 months after received injections than the value before treatment (VAS 49 vs. 82, p<0.001). This effect was most pronounced after 12 months (VAS 27, p<0.0001) and was held after 18 months (VAS 36, p<0.0001). In the second group, pain was lower after 6 months compared to the initial value but deteriorating result was obtained after 12 (VAS 68) and 18 months (VAS 71). Severity of pain in the first group was significantly lower (p<0.001) than in the second group after 12 and 18 months. Functional status of the patients in the first group was significantly higher after 6 (VAS 70 vs. 42, p<0.001), after 12 (VAS 73, p<0.001) and after 18 months (VAS 60, p<0.001) compared to the initial value. In the second group, functional ability of the patients was slightly greater after 6 months (VAS 50 vs. 46) and lower after 12 (VAS 44) and after 18 months (VAS 42). Functional status was significantly higher in the first than in the second group after 6 (p<0.001), 12 (p<0.001) and 18 months (p<0.001). The limitation of motion in the knee joint in the first group was significantly lower 6 months after the initial value (1.7 vs. 2.1, p<0.005). In the second group the limitation of motion was also lower (1.8 vs. 1.9). This effect was maintained in both groups but less pronounced after 12 (in both groups 1.8) and 18 months (1.9 or 2.0), while no significant differences between groups were observed in any of the followed periods.
Conclusions Treatment of secondary OA of the knee in patients with RA with intraarticular injections of hyaluronic acid of high concentration and high molecular weight showed significantly higher efficiency as compared to the same treatment in patients with primary OA.
Disclosure of Interest None Declared