ACL Revision Surgery
Although infrequent in nature, there are certain situations that require a reconstructed Anterior Cruciate Ligament (ACL) to be repaired yet again. Dr. Cunningham has experience and expertise in ACL revision procedures.
Knee Pain Treatment in the Vail Valley
ACL reconstruction surgery has proven to be a successful procedure as reported in hundreds of orthopaedic studies. However, failures do occur. The most common reasons for ACL graft failure are:
- Incorrect placement of the bone tunnels drilled in the femur and/or tibia such that the ACL graft is not in the correct position, leading to abnormally high stresses on the tendon graft, possible graft impingment on the surrounding edges of bone, and premature failure.
- Trauma or new injury.
- Failure of fixation of the graft where it is held to the bone in the early post-operative period.
- Arthrofibrosis or development of scar tissue leading to stiffness, pain, and swelling.
Revision (or redo) ACL reconstruction is a procedure that Dr. Cunningham commonly performs as patients are referred to him when surgery elsewhere has failed.
In order to successfully revise an ACL, the tunnel position has to be perfectly anatomic thus matching the normal origin and insertion points of the ACL for that particular patient. In the majority of cases Dr. Cunningham has to alter the position of the ACL tunnels. This is accomplished in either one or two surgeries depending on the position and diameter of the existing tunnels and whether bone grafting of the tunnels is required.
If Dr. Cunningham can work around the existing tunnels to perfectly place the new tunnels, then the revision ACL can be completed in one surgery. However, at other times, the tunnels in the femur and tibia have expanded and are big, vacuous holes that first need to be bone grafted in an initial surgery. Then, 3–4 months later when the bone graft has solidly filled in these bone defects, Dr. Cunningham can redrill the tunnels and place the new ACL graft in the proper position in the knee.
When bone grafting of tunnels is required, Dr. Cunningham usually utilizes cadaver bone, but the patients own bone can also be used. Using cadaver bone is usually adequate and less painful. However, there are circumstances where it is best to use the patient's own bone. When harvesting bone from the patient, the bone graft is typically taken from the top of the tibia (shinbone), just below the knee, but sometimes it is taken from the pelvis bone, if the defect to be grafted is especially large. After taking this bone graft from the patient, the defect that was created is filled with cadaver bone, which acts as a scaffold allowing the patients own bone to replace it over time.
Results in orthopaedic studies of revision ACL reconstruction have not been quite as successful as first time ACL reconstruction, but Dr. Cunningham has enjoyed very good success in his cohort of revision ACL patients. However, rehabilitation after revision ACL progresses more slowly than primary ACL reconstruction.
ACL Repair or “Healing Response”
For decades, orthopaedic surgeons have attempted to repair a torn ACL back to the femur, which is the usual site of failure. Various techniques have been tried including picking the bone to generate a “healing response”, and at times using suture material and anchors to attempt to sew the ligament back to the femur.
Some surgeons have touted the benefits of adding a “super clot,” which is simply blood from the bone marrow that has a low concentration of repair cells or adding platelet rich plasma, which has a somewhat higher concentration of growth factors.
Although these repair techniques are fairly simple for a skilled arthroscopic surgeon, the long-term results are poor for full thickness ACL tears, and currently, Dr. Cunningham does not recommend these repair approaches. In his opinion, any ACL tear that is amenable to this sort of repair is truly only a partial tear and would heal on its own without the need for surgery in the first place.