What is an Osteochondral Autograft Transfer (OATS)?

Our joints are lined with cartilage, a smooth, strong material that helps joints move easily without pain. As we age, or due to activities like sports, this cartilage can wear down and get damaged. When this happens, it can cause pain, swelling, and stiffness in the knee.

One way to fix cartilage damage is with a procedure called an osteochondral autograft transfer (OATS). This surgery involves taking a small piece of bone and cartilage from a less important area of the knee (where it doesn’t bear as much weight) and moving it to the damaged area. This helps repair the cartilage and reduce pain. The procedure is usually done using arthroscopy, a minimally invasive procedure using a camera and small incisions.

The damaged area that needs the graft is usually around 1 cm in size or smaller. This size helps reduce problems at the site where the tissue was taken from.

While microfracture surgery was historically used for smaller defects, OATS may be recommended when microfracture isn’t ideal. For example, OATS is better for patients who are on blood thinners, have a cyst under the damaged cartilage, or need to get back to their activities faster after surgery.

During surgery, the doctor might make a small open incision to help place the bone and cartilage plug exactly where it needs to go. This ensures that the new cartilage fits well and matches the surrounding cartilage.

Post-Surgery Recovery for OATS

After an OATS surgery, patients are usually non-weight-bearing (not allowed to put weight on the knee) for the first 6 weeks. During this time, they will work on daily range of motion exercises to regain their knee mobility.

At 6 weeks, patients can start to put weight on the knee slowly, use a stationary bike, and gradually increase their activity. However, they should not return to full activities until they are fully recovered. This includes getting back to full strength, having no pain or swelling, and being able to move the knee normally. Recovery usually takes about 6 months before patients can safely return to all their regular activities.