Bert R. Mandelbaum, MD, DHL (Hon)
Osteochondral Autograft and Particulate Autograft
Another approach to repairing smaller cartilage defects is osteochondral autograft, in which we take a bone plug graft from the same patient’s knee from an area that is non–weight bearing. In those scenarios, there have been several studies around the world showing significant efficacy.[3,4]
Each of these procedures works only in patients whose defects are smaller than 2 cm2. There isn’t one procedure size that fits all. For example, for an 8-mm defect, osteochondral autograft would work well, because you can just take one plug. On the other hand, osteochondral autograft doesn’t seem to work well in patients over 30 years of age. And if you’re treating athletes who do a lot of jumping, it’s not the best bet because you have to take graft material from the trochlea, which may require a rehabilitation period of longer than 9 months prior to full return to play.Next is another group of procedures, called the “particulate autograft,” where some of the patient’s own cartilage is harvested from another site of the knee, mixed, ground up, and placed into the defect. Typically we take cartilage from a non–weight-bearing surface, such as the notch inside the knee. These procedures are also works in progress. 
Some of the allograft procurement companies have been offering allograft plugs that are 10 mm in size. This development has made this type of allograft more available; previously, one had to wait until a whole condyle became available. Partly for that reason, we’ve been using osteochondral allograft more frequently for these smaller defects in recent years.