Right now the standard rehab after microfracture for full-thickness cartilage tears is to avoid weight-bearing and use continuous passive motion (CPM). CPM uses a device to slowly move the knee through its range of motion. It's usually used for six to eight hours a day for up to eight weeks after microfracture.
Microfracture is one way to enhance healing. Tiny holes are made in the bone just beneath the cartilage. Fibrocartilage fills in where the cartilage is torn and pulled away from the bone.
Researchers are calling the standard rehab procedure into question. Studies show no difference in results with or without the use of CPM. Likewise, putting weight on the leg isn't a problem either. Up until now the theory was that pressure through the joint would disrupt the healing process.
Ask your doctor to review the latest studies on this rehab method. With close supervision you may be able to bypass the six weeks' restriction and return to sports sooner.