If you've been told you have "bone on bone" in your knee, you're dealing with an advanced stage of osteoarthritis where the cartilage that normally cushions the joint has worn down significantly. In some cases, the protective cartilage is nearly or completely gone, meaning the bones of the joint are in direct contact during movement.
This condition affects millions of Americans, particularly adults over 50. Understanding what's happening inside your knee — and what options are available — is an important first step in making informed decisions about your care.