Q: After a very severe ankle injury, I found out I have a hole in the ankle bone that goes clear down to through the cartilage to the bone. The surgeon is recommending something called an OAT procedure. At age 55 (and being a post-menopausal woman), will this work for me? I don't heal as well as I used to.
A: Holes referred to as "defects" in cartilage that go clear down to the bone can be treated with the technique you mentioned: osteochondral autograft transfer or OAT. Osteochondral autograft transfer (OAT) involves removing a plug of cartilage and bone from a healthy area (usually from a non-weight bearing area of the knee) and transferring it into the osteochondral lesion (i.e., hole in the surface of the same person's joint). The word "autograft" refers to the fact that the patient donates his or her own tissue for the procedure.
In a recent study from Korea, surgeons used a second arthroscopic examination a year later to evaluate the results of this procedure used on the talus (ankle bone). It is rare that a second-look arthroscopic exam is possible so the results of this study are important. Quality of bone and cartilage graft were evaluated using the second arthroscopy instead of MRI in order to get a better look at the results.
Using an analysis of many patient variables, the researchers were able to determine the most important factors affecting the final results. They investigated the role of age, gender, body mass index (BMI), duration of symptoms, severity (depth and size) and location of lesion, and presence of bone cysts as predictive factors of outcomes. They also looked at results based on patient satisfaction, pain, function, and activity level.
Ninety-five per cent (95%) of the group reported good-to-excellent outcomes. Age was not a statistically significant factor. The most important variable in the result of the OAT procedure was actually a surgical effect. The surgeon must restore the joint surface smoothly, evenly, and anatomically accurately.
Impingement (pinching) of the surrounding soft tissues must be avoided. The graft shape and size must match the defect as closely as possible. And the graft must be covered over carefully with a patch to prevent "uncovered" areas. It seems that any gaps or uncovered spots quickly fill in with fibrous cartilage. The result is an unstable defect area.
The authors of this particular study suggest longer-term studies (beyond the one-year mark) in order to evaluate changes and look for influencing factors that might not show up in the first 12-months. They also commented that their study was fairly small in terms of number of patients (52 ankles). Therefore the study should be repeated with a larger number of subjects before accepting these results as the final word on the subject.
But it does offer some evidence that your age and potentially your postmenopausal status may not make a difference. These are good questions to ask your surgeon before having this procedure. Reparative surgery is important in this condition to avoid premature arthritic changes that can cause a chronically painful and unstable ankle.
Reference: Yong Sang Kim, MD, et al. Factors Associated with the Clinical Outcomes of the Osteochondral Autograft Transfer System in Osteochondral Lesions of the Talus. Second-Look Arthroscopic Evaluation. In The American Journal of Sports Medicine. December 2012. Vol. 40. No. 12. Pp. 2709-2719.
