Osteochondral autograft transfer

Osteochondral autograft transfer system  (OATS) ( also known as mosaicplasty) is a surgical procedure in which damaged areas of  weight bearing articular cartilage are replaced by healthy cartilage from non-weight bearing  sites in the same  knee.

It is done in patients below the age of 50 years in which there is damage to a small area of cartilage, usually limited to 10-20 mm in size e.g. a small traumatic ulcer. It is not a treatment of knee osteoarthritis.

How is the procedure done:

  • An arthroscope is used to visualized the ulcer and evaluate the condition of the rest of the knee. Any cartilage remnant over the ulcer is removed exposing the underlying bone.

  • Drill holes are made in the underlying bone

  • The drill holes are made vertical to the surface of the joint

  • A special hollow sharp tube is used to obtain cylindrical plugs containing bone covered by cartilage. These are taken from non-weight bearing areas of the knee joint.

  • The plugs are pushed in the drill holes previously drilled in the ulcer.

  • Thus, the ulcer become filled with normal articular cartilage.