The OATS procedure replaces areas of damaged cartilage with grafts of the patient’s own healthy hyaline cartilage. The procedure, also known as mosaicplasty, is performed using small instruments through incisions on the sides of the knee. The surgeon uses a small video camera called an arthroscope to see inside the joint and guide the instruments.
1. Healthy Cartilage Removed
Healthy cartilage is harvested from the collection area, a region that has little contact with the tibia. The amount of graft tissue removed is based on the size and location of the damaged cartilage. The curvature of the graft site is also taken into account.
2. Diseased Cartilage Removed
Diseased cartilage is removed in the same way, creating a socket for the graft.
3. Graft Inserted
The graft is fit firmly into the socket. The graft is tapped into place until its surface matches the level of the surrounding cartilage.
The surgeon may need to use multiple donor cores to fill a larger damaged area. Grafts are placed one at a time until the damaged area is filled. For larger lesions, allograft tissue may be used.
End of Procedure and After Care
The donor areas may be left open to heal. Or, the surgeon may use the bone removed from the damaged area to refill the donor site. After surgery, the patient undergoes rehabilitative therapy. The patient may need to walk with crutches for a few months after surgery.