Osteochondral (Bone/Cartilage) Transfer Procedure In The Knee              The knee is subjected to many types of trauma in everyday living or sports that can cause damage to the surface of the rounded upper portion of the knee joint. Sometimes these damaged areas can be seen on plain x-rays. Sometimes they are better seen on MRI x-rays or even at the time of arthroscopic surgery in which the knee joint is being viewed directly. If the area affected is not extensive it, in many cases, lends itself to a special procedure that has been developed to try to recover the damaged area of the joint. This is done by harvesting good bone and cartilage from another area of the knee joint and transferring it to the damaged area.     The procedure is sometimes called mosaicplasty. It was first done in the early 1980 by Dr. Laszlo Hangody in Hungary. It has become popular to do this procedure in the United States in the last few years.     Instrumentation has been developed to take small plugs of bone, between five and ten millimeters, from a somewhat out of the way, unaffected area of the knee and transfer these plugs to the damaged area.     In a way, it could be compared with what dermatologists have been doing for many years in their hair transplant work.     Specialized instruments have been developed which consist of thin walled cutting tubes that are used to harvest plugs of bone capped with healthy cartilage that can be transferred to the damaged area. Plugs of bone are removed from the damaged area to then receive the transferred plugs from the good area of the knee.     In some cases this can be done by arthroscopic technique, but it often requires an open incision component to complete the surgery.     The donor areas are routinely left open after harvesting and have been shown to fill in with bone and fibrocartilage within two or three months.     While this technique is a newer one in the United States, it shows great promise in those conditions of the knee in which damage is somewhat localized. It is not something that can be used on generalized damage or arthritis changes in the knee in which a larger area of the knee has been affected.     It does have a limited application and does not apply to every knee problem by any means, but we have found it to be an extremely valuable addition to our program to repair damaged knees. The early results with the technique have been very promising and we have great hopes that in the future even more patients will be helped by this interesting, but demanding technique.     Dr. Hangody recently presented his work in this area at the American Academy of Orthopaedic Surgeons annual meeting in Orlando, Florida and I was fascinated to learn how he developed this surgical treatment of damaged knees as I listened to this lecture.     The technique is sometimes referred to as the OATS procedure, which is an abbreviation for Osteochondral Autograph Transfer System.