The document discusses joint replacement surgery, focusing on which joints are most commonly replaced and when a patient should consider having the surgery. It notes that hip and knee replacements are most common, performed on over 100,000 people annually in the UK. It then explores the views and behaviors of various parties involved in the joint replacement process, including patients, general practitioners, and orthopedic surgeons. Based on research involving patients, it concludes that pain and disability level should be the main criteria for considering surgery, rather than a doctor's focus on age, weight or x-ray findings alone. It recommends developing local appropriateness criteria involving patients, doctors and other staff to help make decisions more consistent and fair.