Patients who need a total knee replacement or have recently had a total knee replacement with the Smith and Nephew Porous Total Knee System will be enrolled into the study. Before surgery X-rays will be collected and questionnaires will be administered which ask the patient about knee pain, activities of daily living, quality of life and how they feel about their knee. The same X-rays and questionnaires will be asked before surgery and then after surgery at various intervals up to 10 years post-surgery.