Study goals: The aim of this study is to determine the quality of life of patients with stage 4 of osteoarthritis of the knee joints according to the Outbridge classification and regarding patients older than 60 years of age. The specific objective of the research is to, by using a standard questionnaire, assess three domains: pain in the joints, assessment of mobility, and difficulties in performing physical activities. Study drafting: A retrospective study was conducted at the Department of Traumatology and Orthopedics, at the General County Hospital in Pozega. Methods and participants: The study group consisted of 51 patients with degenerative changes in the knee joints, and who were fitted with a total endoprosthesis of the knee joint, and were treated at the Department of Traumatology and Orthopedics at the General County Hospital Pozega. The survey was conducted in March and April 2016. The study included patients over 60 years of age with stage 4 of osteoarthritis of the knee joints. Results: according to a scale of 0-100; the level of the intensity of pain was 80, the level of mobility 88, the level of discomfort while performing physical activity 79, and the level of quality of life showed as 77. Conclusion: According to the analysis of the results obtained using a standardized questionnaire, the majority of patients presented with severe pain, great immobility and increased discomfort when performing physical activity. In conclusion, bad quality of life of respondents is confirmed.