You are correct. One technique that doctors can use to repair cartilage in the knee is called microfractures. To do this procedure, the surgeon makes a small incision in your knee and inserts an awl to drill tiny holes into the bone, as close as possible to the tear or hole in the cartilage.

When the holes have been drilled, some bone marrow will seep out of the holes and then begin to clot. This allows cartilage-building cells to form and the hole or tear will be repaired.