Knee joints injury in rheumatoid arthritis patients appear in 70 % cases. This is the most common cause of loss of work capacity, the ability to self-care. Patients become severely disabled, in that the disease is accompanied by deformations with the development of discordant positions of the lower limbs, which lead to a partial or complete loss of the function of support and walking, so this problem needs to be studied. Objective. To make an analysis of orthopedic treatment of secondary arthrosis of knee joints in RA patients, complicated by deformities depending on the age and gender of the patient, stage, duration of the disease and activity of the inflammatory process. Methods. In this work we have analyzed the orthopedic treatment of 66 RA patients with secondary arthrosis with axial deformities, who underwent 75 total endoprosthetics between 2013 and 2020. Anamnestic data, clinical, biomechanical and statistical research methods were used. The obtained data were evaluated using the scale of Joseph J., Kaufman E. E. Results. The analysis of the results of knee joint replacement was followed in the period from 6 months to 5 years. The results were carried out according to the 100-point scale Joseph J., Kaufman E. E. (1990). Thus, the analysis of the results of total knee arthroplasty in patients with RA according to the scale of Joseph J., Kaufman E. E. showed that good results were obtained in 46 (79.31 %) patients, satisfactory results in 11 (18.97 %) and unsatisfactory results obtained in 1 (1.72 %) patients. The reliable relationship of the level of joint deformation with the level of disease activity and with the scale of Joseph J., Kaufman E. E. was researched. Other indicators are not reliably correlated with the level of joint deformation. As a result of pairwise comparisons of groups with each other using the Duncan test, a significant increase in the degree of joint deformation was found in the group with activity 3 compared to the group with activity 1. The use of basic or complex therapy does not reliably affect the degree of joint deformation. Conclusions. Total knee joint replacement need patients with II stage of the 2nd phase of the disease and higher. In our opinion, this is the most optimal time for surgical treatment, which allows patients with RA to fully use the possibilities of an implanted endoprosthesis.