A mosaicplasty uses cartilage from undamaged areas of the joint, and moves this cartilage to a damaged area. This type of procedure is only useful for the treatment of focal cartilage damage. This means the widespread damage of cartilage seen in conditions like osteoarthritis cannot be treated with mosaicplasty. This treatment is only used for isolated areas of cartilage damage, usually limited to 10-20 mm in size. This type of damage is usually seen in younger patients (less than 50 years old) who experience a trauma to their joint.
The OATS procedure, developed by the Arthrex corporation, is one type of mosaicplasty. Small "plugs" of cartilage and removed from areas of the joint where the body can do without the cartilage, and these are moved to the damaged area of the joint.
Often the surgeon will consider this type of procedure, but if x-rays or arthroscopic examination show evidence of more widespread cartilage damage, the OATS procedure will not be performed. The reason is that the OATS procedure will not benefit these patients.