Was given one of these several years ago as shoulder, painfully, clicked when moved. Was like a miracle. After about five years had a further one there, did the trick, but not see brilliantly. Have also had these in my hip. Was told that the maximum number is three at any one site.
The only ones that did not do anything at all, were very carefully guided ones for my thumbs. These were the most painful injections, I think, I have ever had. Pain increased over next two or three days, wore off, and my thumbs just went back to how they had been for several years. Would NEVER try to repeat that.
All done under NHS