When examining a patient who fails his or her first ACL reconstruction, it is important to determine if the cause of failure could be malalignment of the knee joint. Patients who have a varus deformity, also known as “bowlegged,” are more likely to have failure of ACL reconstruction. Due to an imbalance of forces, the inside of the knee has more weight placed upon it, and consequently the knee starts to turn inwards and wear down the joint cartilage unevenly, causing pain and osteoarthritis. Additionally, this unnatural alignment can place stress on the reconstructed ACL, making it more likely to tear when playing sports or performing other high-intensity activities. The below x-ray is from a patient with varus deformity of the left knee. Compared to the right, the patient’s left shinbone (tibia) shifts inward, placing unbalanced forces on the knee.
Recently, Clinical Orthopedics and Related Research published a study that examined the linkage between failed ACL reconstructions and the need for an osteotomy prior to revision surgery. An osteotomy, specifically, a high tibial osteotomy, is a surgical procedure that realigns the knee joint, taking the stress off the inside of the knee and redistributing weight on the joint. The study determined that there is a higher incidence of varus deformity in ACL revision patients compared to patients undergoing their first ACL reconstruction.
Surgically, an osteotomy involves making a vertical incision along the inside of the knee, exposing the shinbone, or tibia. A specialized saw is used to make a cut along the tibia, and this cut is opened to create a triangular wedge of space inside the tibia. The exact size of the wedge will be determined by your surgeon prior to surgery, using standing x-rays that will determine the degree to which the joint needs to be realigned. A bone graft or bone graft substitute is inserted into the wedge-shaped gap and secured with surgical plates and screws. Recovery from high tibial osteotomy typically involves the use of crutches for six or more weeks and the use of a brace to protect the joint. Below, the same patient’s knee is shown on x-ray after having undergone a high tibial osteotomy. Compared to the prior x-ray, the left knee shows much better alignment and there is less stress on the inside of the knee.
After a successful osteotomy, a patient can then have his or her ACL reconstructed. Although the recovery from an osteotomy can be arduous, fixing a varus deformity by osteotomy gives a patient the best possible chance for a successful ACL reconstruction later. If you or someone you know is contemplating revision ACL surgery, schedule a consultation today with Dr. Eric Millstein to find out if an osteotomy could help you have a more successful ACL reconstruction.