A second replacement has to be larger for surgeons to be able to fuse it to healthy bone. And the larger implant then reduces the patient's mobility even further. With the aid of a viewing device inserted through a periscope-like arthroscope, Rodrigo removes any remnants of cartilage and debrides the bone with a sharp blade. He then uses a second arthroscope to insert needlelike awls with a diameter no thicker than the width of a dime. He uses the awls, which look like tiny ice picks, to poke holes into the bone down to the marrow.
Rehabilitation begins the next day.
It grows by itself, said Rodrigo, from precursor cells that ooze from the bone marrow onto the scraped bone surface. The advantages of the procedure are simple. The success rate for this procedure, which is performed around the country, is about 80 percent. Success is defined as a return of function to within 10 percent to 20 percent of what it was before injury. Compared to the typical 50 percent reduction of function in patients when they come for treatment, it is a significant improvement.