I have had knee problems for quite sometime now. Last year I had a shot of cortisone which really helped when I developed a baker's cyst. Since my ankles also ache and crack, I have just blamed the imbruvica which I have been on for 25 months (and doing fantastically). Yesterday I returned to my orthopedic doctor because now both my knees have been quite bad. He gave me another shot of cortisone, and I will return in two weeks for a shot for my other knee. I expected to hear that yes, it was the imbruvica, but the doctor said I had severe arthritis and that most in my condition would be having two knee replacements. Since that is not be possible, I will just hope to be able to make it as long as possible, and then return for another shot as needed. Strange as it may seem, it was actually a relief to hear that it was arthritis. I have done some research and not been able to find imbruvica as a cause of arthritis. To be fair, I had some arthritis before ever even being diagnosed, and it does run in my family. For those wondering why they have joint and muscle pain, you might want to check in with an orthopedist.