The purpose of this study is to investigate the relationship between the clinical and radiographic severity of knee osteoarthritis (OA) and the serum levels of specific biomarkers, namely Fetuin-A and Cartilage Oligomeric Matrix Protein (COMP). Osteoarthritis is a degenerative joint disease characterized by cartilage breakdown and low-grade inflammation. Investigating these biomarkers may help healthcare providers better understand the disease pathology, potentially leading to earlier diagnosis and improved tracking of disease progression. The study will compare two distinct groups: a patient group consisting of 120 individuals diagnosed with Grade 2-4 knee osteoarthritis, and a control group of 60 age- and sex-matched healthy volunteers with no history of joint disorders. Participants will undergo radiographic evaluations using the Kellgren-Lawrence classification system, alongside clinical and functional assessments, including pain severity scales, mobility metrics, and functional questionnaires. Fasting blood samples will be collected from all participants to measure serum Fetuin-A and COMP levels via laboratory analysis, and the Systemic Inflammation Response Index (SIRI) will be calculated. The collected data will be statistically analyzed to determine if biomarker levels significantly correlate with the severity of knee joint degeneration and functional impairment.