Osteochondritis Dissecans is a condition where a fragment of bone that helps support the joint surface loosens. This can occur in the knee and usually affects the end of the thigh bone or femur. This is often first discovered in the teenage years. The exact cause is unknown. If the piece of bone is becoming loose, it can cause pain or discomfort. As it loosens more, the piece or pieces of bone with their overlying joint surface (cartilage) can fall into the joint and become “loose bodies”. These can then move about the knee occasionally getting caught between the bones as the knee bends and straightens. The divot or defect left from the piece falling out can cause trouble as well.
The treatment for Osteochondritis Dissecans depends on how loose (unstable) the piece or pieces are, how large the area involved is, and how critical the location is. Options include protecting the area from stress hoping for healing, arthroscopic surgery to remove a loose body, or bone grafting and using screws to stabilize the fragment to allow it to heal to the rest of the bone. If the piece cannot be salvaged and it is large enough and in a critical location, there are techniques that can resurface the joint. Two of these borrow a piece of bone with its overlying cartilage from either a less critical part of the knee (osteochondral autograft) if smaller in size, or from a cadaver tissue donor (osteochondral autograft) if larger in size.