At 56 (and counting), the old knees do pop every now and then, especially following any period of inactivity (like sitting in a treestand).
My bow arm, wrist and hand were kinda put back together after having a horse roll over on me (as they say; if you have horses, you are going to get hurt!). I ended up with a compression fracture that left everything about 3 inches shorter than normal. Basically all the bones pretty much disintegrated.
The orthopedic surgeon that put everything back together said I would have severe arthritis in that arm(/wrist/hand) within 5 years. This was over 17 years ago. I thank my lucky stars that arthritis hasn't reared its ugly head, but, I will admit to somewhat creaky elbows in both arms.
Creaks, pops, etc. are all part of getting older. Go with the flow, keep shooting, and hope that the animals don't ID you by hearing those noises.