I haven’t had a mechanical sound- but I was having a bumping feeling in my left knee. I’ve had both knees replaced. One about 3 years ago and the second about 2 1/2 years. The bumping started about 1 1/2 after the surgery and stopped after about 9 months later after Doctor did an in office cleanup. The doctor thought it could be scar tissue. It was a weird feeling.
Lately, the same knee feels tight. Our knees are so aggravating! They never stop.