I would really appreciate any comments related to knee replacement or similar surgery. My Father has PD. He had a knee replaced one month ago, with two major negative consequences: 1) his leg's tremors and involuntary movements have caused the replacement to "unhinge" twice already, requiring additional surgery. Now the doctor is considering replacing the new knee replacement with a different model, which only bends to 90 degrees. Of course this means again, surgery and all that it implies. 2) after two surgeries under general anesthesia, he experienced extreme disorientation for about two weeks. Has anyone had similar experiences? My Mother cares for him, and she shows some of the symptoms mentioned by Alan Bonander in a previous message. I can not help very much, because both my parents live in Guatemala. But I can keep them updated with useful information that I am gathering from this list. With thanks for any experiences you can share with us, Grete.