What is a intra articular fusion mean in the knee? what causes the knee not to straighten? please help

Fused joints: Hi Nancy, The knee joint is an example of a joint, which is where your bones come together, or articulate. A joint fusion is usually a surgical procedure performed to achieve a pain-free knee when other surgical procedures are not indicated. Some patients have bony ankylosis where the bones are fused due to trauma or other disease. Your Orthopaedic Surgeon is the specialist to properly treat you.