These is a beautiful example of the tibial bone at the knee joint showing what arthritis looks like. The arrow points to where the padding of the joint, or articular cartilage has rubbed off exposing the underlying bone (as compared to the other side with the articular cartilage still intact). This causes bone on bone pain. This disease process is also referred to as wear and tear on the joints, osteoarthritis or degenerative joint disease (DJD).
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