Describing pain to doctors is beyond frustrating. They only understand basic pain. Chronic pain is a whole different thing. Your pain meds obviously aren't helping, so why take them? I know how it is when the pain is more than you can handle. I also know how it affects your mind. I swear there is nothing louder than the sound of overwhelming pain. Especially when you can't stop the pain even when you try to rest. Marijuana will help, but you obviously need a more permanent relief.
First you have to change doctors. I found a very progressive surgeon in Dunmore, PA USA. I know there is an experimental surgeon in Seattle, WA USA. I don't know what there is in Istanbul. You may need to travel. Ask your family doctor where the closest world renowned joint replacement center is in Europe. The next few surgeons probably won't know what to do for you, so ask them where they would go if THEY needed the latest technology. I don't like fusion, I think it is a bad surgery. If they suggest that, I think you can dismiss them as under qualified for your situation.
Joint replacement worked for me. Before surgery my mind had turned to mush. So much of my mind was focused on trying to deal with the pain that I couldn't think of much else. Occasionally I am a little sore, but I haven't had overwhelming pain even once since surgery. If you want someone to talk to, you can e-mail me at bsanva@yahoo.com. I may not have all of the answers you need, but I do understand your current situation. If you think you want to consult with a doctor in the USA I can give you a couple of suggestions. I am sure there are many in Europe as well, I just don't know who any of them are.