Osteochondral fractures are breaks in the joint lining where a piece of the articular cartilage (the cartilage overlying the end of the bones) breaks off with a piece of underlying bone. They have a traumatic cause and result in a rapid swelling of the knee. The fragment that breaks off can act as a loose body in the knee and lead to pain and mechanical symptoms.
If the diagnosis is made acutely and the fragment is of a reasonable size, the fragment can be fixed back on to the joint surface. If the diagnosis is delayed the fragment may need to be removed and the defect filled with a cartilage graft.