Wonder what people come up with on how this problem is caused; My first idea would be the Thick oil like lube that is Covered by the Tough Layer of Ligaments Maybe the Layer of Ligaments is Damaged some how releasing all the oil lube that protects the joints Poping Fingers, Cracking Knuckles, Sleeping on your hand in a wrong position or songihtme. I think it be helpful if people post there thoughts on what causes this i dont have this but im afraid in the future a family member will or myself