OATS is an abbreviation for a procedure where a core of healthy cartilage and bone is taken from an unimportant area of the knee to replace a more important damaged area.
Page updated January 2024 by Dr Sheila Strover (Clinical Editor)
A plug of healthy bone and cartilage is taken from elsewhere in the body and press-fitted into the defect, where it will heal.
What does OATS stand for?
OATS stands for 'Osteochondral Autograft Transfer System' - which means a bit of joint cartilage and underlying bone is taken from the patient and transferred from a relatively unimportant healthy bit of the joint to replace a damaged area in a more important area.
Indications for OATS
The OATS procedure is indicated in the younger symptomatic patient who has a chondral defect of 2 cm or less on the condyle of the femur, and who has other surgical and conservative efforts to relieve symptoms, and where other factors are normal such as the mechanical alignment, and there are no problems with the ligaments or menisci.
By transferring a core of healthy cartilage together with the underlying bone, the area should heal well and be covered by true cartilage, rather than fibroscartilage, which often is the result of other repair procedures such as ACI.
What sort of rehabilitation is required after OATS surgery?
For the first three weeks after surgery the patient needs to be non-weight-bearing. From weeks 4-6 toe touchdown is allowed but weight-bearing is limited to 25% of the body weight of the patient, measured by the physiotherapist.
This is a useful reference.
- Re: Hugh's microfracture diary
A patient jumps into a good discussion about cartilage repair.
"Without purposeful intervention, chondral lesions within the knee joint can be functionally debilitating, predispose to early osteoarthritis, and limit return to sports and daily activities....The osteochondral autograft transfer system (OATS) procedure is at the forefront of cartilage restoration surgeries of the knee...."
Citation: Guzman AJ, Dela Rueda T, Rayos Del Sol SM, Bryant SA, Jenkins S, Gardner B, McGahan PJ, Chen JL. Arthroscopic Osteochondral Autograft Transfer System Procedure of the Lateral Femoral Condyle with Donor-Site Backfill Using Osteochondral Allograft Plug. Arthrosc Tech. 2021 Nov 9;10(12):e2683-e2689. doi: 10.1016/j.eats.2021.08.012. PMID: 35004149; PMCID: PMC8719136.