Define osteoarthritis and describe its epidemiology and pathophysiology. Identify key clinical features of osteoarthritis, including history and physical examination findings. Interpret relevant investigations, including X-ray findings and when advanced imaging is needed. Classify osteoarthritis severity using common grading systems (e.g., Kellgren–Lawrence). Develop a systematic approach to diagnosis, differentiating osteoarthritis from other causes of joint pain. Explain evidence-based management principles, including lifestyle modification, pharmacologic treatment, and intra-articular therapies. Outline indications for surgical intervention, including arthroscopy, osteotomy, and joint replacement. Discuss complications and prognosis, emphasizing long-term follow-up and patient education.