ACL Primary Repair with Central Augmentation Q&A with Gregory S. DiFelice, MD
Q: At the last Faculty Forum meeting, you presented on your concept of ACL Preservation. Can you discuss what you mean by this?
A: ACL Preservation refers to my approach to the treatment of ACL injuries. It is a novel and progressive approach that focuses on trying to save as much of the native ligament remnant as possible. The current standard of care is reconstruction that generally resects the ligament remnant and reconstructs the ligament with one of multiple graft choices. With my approach, I use reconstruction as a last resort. For many of my patients I am able to save most, or all, of their native ligament with several techniques that I have developed in collaboration with Arthrex. (1, 2)
Q: In your last blog entry you updated us on your ACL Primary Repair technique. Can you discuss the augmentation technique that you use?
A: My approach of preserving the native ACL tissue started with my work on ACL Primary Repair (1) for proximal avulsion tears. As my skills and results improved, I became frustrated that I couldn’t repair more tears. Far more tears are proximal 20% tears, than are avulsion tears, and after attending ArthroLondon in 2012 and hearing Dr. van der Merwe’s lecture on Biologic ACL Reconstruction, I had an epiphany. It dawned on me that I could combine his technique of augmenting the ligament with my technique of repairing the remnant to avoid the rather high rate of Cyclops lesions (a ball of scar tissue created by the sagging ligament remnant that blocks knee extension and can cause pain) that can complicate standard augmentation techniques. The resultant technique is called ACL Primary Repair with Central Augmentation and the technique video can be viewed on Arthrex.com (2).
Q: Are there any differences between augmentation and reconstruction besides preserving the remnant?
A: Yes, augmentation is a more conservative approach than reconstruction in many ways. Preserving the remnant maintains the native ligament tissue, nerve endings and blood supply with obvious benefit. Thus, it is not necessary to use such a large graft like is used in the typical reconstruction. Typical reconstructions create 10 mm tunnels in the femur and tibia to place the graft into. Using a 7 or 8 mm graft in a reconstruction generally makes the surgeon somewhat nervous about the graft not being strong enough, however, this is routine in an augmentation. Maintaining the remnant obviates the need to use such a large graft and conserves bone.
Q: For what percentage of your patients are you able to use your ACL Preservation approach?
A: Currently, my ACL Preservation approach encompasses ACL Primary Repair and ACL Repair with Central Augmentation as mentioned. Using this approach, I am able to save most, or all, of the native ligament for approximately 50% of my patients. This, to me, is a tremendous advantage over the standard reconstructive approach in that native tissues are preserved with all of the concomitant benefits. At the same time, very few surgical bridges are burned, such that revision surgery, when needed, is almost like performing a primary reconstruction.
Q: Have you noticed a difference in the postoperative course and rehab with augmentation versus reconstructions?
A: Interestingly, I have. At first, I didn’t think that there would be much of a difference between the two techniques since tunnels were being drilled in both cases. However, anecdotally, I have definitely noticed that the augmentations seem to have less pain and swelling and a more stable/normal knee subjectively and objectively in follow-up. I explain to my patients that instead of having a “one size fits all” approach to ACL surgery that is currently the standard of care in my mind, I offer a customized approach to ACL injury. I utilize small (repair), medium (augmentation) and large (reconstruction) surgeries, depending on the nature of the ligament injury and the quality of the remnant tissue. For each patient, the final decision as to which procedure is best suited for them is made on the table when the tear type and tissue quality are determined intraoperatively.
Q: As ACL Preservation seems like a rather intuitive approach to ACL injury, why do you think such an approach wasn’t adopted historically?
A: The answer to that question is best summed up by the old saying “hindsight is 20/20.” Original attempts at repair were performed open, on all injury types and heterogeneous patient populations that yielded mixed results, at best. This led some authors to move towards augmentations that actually had somewhat more predictable results, even when done open. However, at right about the same time, arthroscopy was coming to the forefront, and in the early days of arthroscopy the technology, the instruments and the surgical skills were not sophisticated enough to preserve the remnant. I like to say that the first surgeon to look good performing an arthroscopic ACL reconstruction was the first surgeon to resect the entire ligament so that they could see what they were doing. Once that bridge was burned there was very little discussion about remnant preservation in the literature for the ensuing 25 years or so. Current imaging technology, anatomic and biologic understanding, and both surgical technology, and skill, have enabled us to reinvigorate the discussion of what was, in my mind, the right idea at the wrong time.