Osteoarthritis (OA) is the most prevalent form of arthritis, characterized by structural and functional changes in synovial joints. It is a multifactorial process with mechanical factors playing a central role. The disease is not curable, and current treatments focus on reducing pain and improving joint function. OA affects the entire joint, including subchondral bone, menisci, ligaments, periarticular muscles, capsule, and synovium. The prevalence of OA varies, but about 6% of adults aged ≥30 have frequent knee pain and radiographic OA. Risk factors include age, sex, obesity, and nutritional deficiencies. Diagnosis is based on clinical presentation and radiography, with symptoms such as pain, stiffness, reduced movement, swelling, and crepitus. Treatment aims to educate patients, control pain, improve function, and alter the disease process. Non-pharmacological treatments, such as education, weight loss, exercise, and physical therapy, are recommended first. Pharmacological treatments include analgesics, intra-articular steroids, and hyaluronan. Surgery is considered when other treatments fail, particularly for severe pain and functional limitations. Osteotomy and joint replacement are effective options, with joint replacement being irreversible and suitable for those who do not respond to other treatments. The aging population and increasing obesity will further increase the societal burden of OA. Research is ongoing to develop new treatments to slow disease progression.Osteoarthritis (OA) is the most prevalent form of arthritis, characterized by structural and functional changes in synovial joints. It is a multifactorial process with mechanical factors playing a central role. The disease is not curable, and current treatments focus on reducing pain and improving joint function. OA affects the entire joint, including subchondral bone, menisci, ligaments, periarticular muscles, capsule, and synovium. The prevalence of OA varies, but about 6% of adults aged ≥30 have frequent knee pain and radiographic OA. Risk factors include age, sex, obesity, and nutritional deficiencies. Diagnosis is based on clinical presentation and radiography, with symptoms such as pain, stiffness, reduced movement, swelling, and crepitus. Treatment aims to educate patients, control pain, improve function, and alter the disease process. Non-pharmacological treatments, such as education, weight loss, exercise, and physical therapy, are recommended first. Pharmacological treatments include analgesics, intra-articular steroids, and hyaluronan. Surgery is considered when other treatments fail, particularly for severe pain and functional limitations. Osteotomy and joint replacement are effective options, with joint replacement being irreversible and suitable for those who do not respond to other treatments. The aging population and increasing obesity will further increase the societal burden of OA. Research is ongoing to develop new treatments to slow disease progression.