Articular cartilage covers the
ends of bones in joints throughout the body. Normal cartilage is smooth
allowing easy gliding of the joint. When cartilage is injured, the smooth
surface can become rough. Cartilage is unable to heal or replace itself.
Occasionally the cartilage injury is severe and there is complete loss of
cartilage resulting in exposed bone. Sometimes called OATS or Mosaicplasty osteochondral
grafting is a method of treating cartilage injuries that expose underlying
bone. Osteochondral grafts 
The injured area of cartilage is
identified and a core of the injured cartilage and the underlying bone is
removed in a method similar to coring an apple. A replacement core made up of
cartilage and bone from another site in the knee (autograft) or a tissue donor
knee (allograft) is then made to fit into the hole. The replacement core is gently
tapped into place until it lines up with the surrounding tissue. It acts as a
pressfit. No screws or other devices are typically needed to hold the
replacement core in place since it fits tightly. Frequently it can be performed
all arthroscopically.
Patients can usually start to
bear weight within 4-6 weeks of surgery. Activity is gradually increased with
return to sport typically occurring after 6-9 months.
Patients often recover very well from
both of these procedures. One advantage of these techniques is the ability to
replace both cartilage and bone with similar tissue. There are limitations to
the amount of tissue that can be taken from within a patient’s own knee so
larger areas of cartilage loss may not be best for this approach. A potential
concern with the use of donor tissue is the very low risk of disease
transmission (like a blood transfusion). Although these techniques are new to
have data on how well patients recover in the long term, it has been seen that
these patients frequently do very well.
