ACL Preservation Q&A with Gregory S. DiFelice, MD

Dr.DiFeliceQ: It has been about a year since your last blog entry, what is the update with regard to ACL Preservation?

A: There are a number of interesting things that have occurred since we last spoke in this forum. First of all, my patients continue to grow in numbers and in successful outcomes. I have performed 38 arthroscopic ACL Primary Preservations for isolated ACL injured patients to date, and probably closer to 50 if you include those patients with ACL avulsions in the multiple ligament injured knee (MLIK) setting. I continue to run at right around the 90% clinical success mark. The failures, except for one of the early patients who failed at around 3 months, occurred after repeat trauma at more than a year postoperatively playing soccer and rugby.

Secondly, I have modified the technique slightly after considering the basic science research of four separate papers that showed that adding a suture construct connecting the femur to the tibia in parallel with the repair improves the early biomechanics (1-4), potentially protecting the early repair. This is essentially the InternalBrace® concept that has been gaining popularity throughout the body since Dr. Mackay introduced it several years ago for the knee MCL. I have used this technique, in various forms, in over half of my ACL Primary Preservation patients.

Finally, I presented the two- to six-year (avg. 3.5 years) clinical results of my first 11 patients as an ePoster (5) at the April 2015 Arthroscopy Association of North America (AANA) conference that was held in Los Angeles. In addition, I presented the findings of a bench study comparing my suture anchor primary repair to a conventional transosseous button repair in a simulated active motion cadaveric model as an ePoster (6) at the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) meeting in Lyon, France in June. I also anticipate publishing a series of papers later this year in a high impact factor, peer-reviewed journal; one as a systematic review of ACL repair literature over the last decade and the other as a clinical paper detailing my experience with my first 11 arthroscopic ACL Primary Preservation patients. Hopefully, this will catapult arthroscopic ACL Primary Preservation into the mainstream ACL discussion.

Q: What has the response been to your latest research and presentations?

A: Since Arthrex released my 2014 Faculty Forum presentation on ACL Primary Preservation, and the subsequent surgical technique video, I have been contacted multiple times by other surgeons who are intrigued by the idea or have tried a few themselves with good results. Arthrex’s global reach certainly ignited a buzz regarding this topic. However, let’s not forget that the worldwide ACL surgeon community effectively gave up on this concept over 30 years ago. In reality, aside from long-term follow-ups of the original open ACL repair cohorts, there hasn’t been a single publication regarding new techniques for ACL Primary Preservation or ACL Primary Preservation outcomes in human beings in over 30 years. Thus, I am excited about the recent ePosters and the forthcoming publications.

Q: Do you think this will become a mainstream technique for ACL patients?

A: It is unrealistic for me to argue that my early to mid-term results on less than 50 patients will change the mainstream thinking regarding ACL surgery. However, that was never my goal. My goal, first of all, was to do what I felt was right for my patients in my hands. Next, my goal was to share my concept and my experiences in order to start a discussion that, in time, might possibly change our collective approach as groupthink kicks in. It is hard for me to imagine that surgeons will not adopt such a minimally morbid procedure for select patients seeing that no bridges are burned if the repair fails. This cannot be said for modern day ACL reconstruction that has far from perfect results. Admittedly, my numbers are rather low thus far, and there are several things at play here. First of all, I have been very meticulous in my indications by trying to limit the application of the procedure to only those with the perfect Type 1 proximal avulsion type tears. These tears may only represent 5-25% of the tears depending on the practice mix that the surgeon sees. Furthermore, my practice is rather broad in focus, and not limited to only ligamentous injuries of the knee. 

Q: Even though only a small percentage of patients seem to meet the indications for ACL Primary Preservation in your practice, has your experience thus far changed the way that you approach all patients with ACL injuries?

A: Absolutely. First of all, the great majority of my ACL Preservation patients have recovered quickly, and with good outcomes, that I wish that more of my patients met the criteria for repair. I recently saw a patient, my 37th repair, back at one-month post-op who illustrates this point well. He detailed that he had full range of motion within one week, and that since one-week post-op, he had been commuting an hour and 15 minutes each way to work via train with a lot of standing and walking. He explained that he didn’t have any significant swelling or discomfort after the first week despite these long hours on his feet. Interestingly, he had undergone an autograft BTB on the other leg eight years earlier so he had his own internal control. Needless to say, thus far, he is a believer.

Seeing my patients doing so well after Primary ACL Preservation, I became more frustrated when I encountered ACL remnant tissue that wasn’t quite long enough to reach the wall. You see, once you get in the habit of saving the ligament if possible, then resecting significant portions of ligament remnant doesn’t seem like the right thing to do. It seems that I am not alone in this sentiment as numerous authors, mostly from Europe and Asia, have published on remnant preserving or sparing ACL reconstruction. After seeing Dr. van der Merwe’s presentation on “Biologic ACL Reconstruction,” at ArthroLondon in 2012, I realized that augmenting the ligament remnant with a hamstrings graft had significant theoretical biologic benefit. However, to avoid cyclops lesions that tend to be common when augmenting the remnant, I developed a technique to combine my ACL Primary Preservation technique with his Biologic Augmentation. Arthrex released the surgical technique video last year that describes what I call ACL Preservation with Central Augmentation.

In my clinical practice, I have adopted an ACL Preservation approach. Essentially, I attempt “Preservation,” or “Preservation and Augment,” in as many torn ACLs as I can so as to customize the surgical approach to the injury pattern. Since I have adopted this approach in September 2012, I have evolved to the current day where I am able to save all or most of the ligament in nearly 50% of patients.



1. Fleming BC, Carey JL, Spindler KP, Murray MM. Can suture repair of ACL transection restore normal anteroposterior laxity of the knee? An ex-vivo study. J Orthop Res. 2008;26(11):1500-1505. doi: 10.1002/jor.20690.

2. Murray MM, Magarian E, Zurakowski D, Fleming BC. Bone-to-bone fixation enhances functional healing of the porcine anterior cruciate ligament using a collagen-platelet composite [Published online ahead of print June 11, 2010]. Arthroscopy. 2010;26(9 Suppl):S49-S57. doi: 10.1016/j.arthro.2009.12.017. 

3. Fisher MB, Jung HJ, McMahon PJ, Woo SL. Evaluation of bone tunnel placement for suture augmentation of an injured anterior cruciate ligament: effects on joint stability in a goat model. J Orthop Res. 2010;28(10):1373-1379. doi: 10.1002/jor.21141.

4. Fisher MB, Jung HJ, McMahon PJ, Woo SL. Suture augmentation following ACL injury to restore the function of the ACL, MCL, and medial meniscus in the goat stifle joint [ published online ahead of print April 6, 2011]. J Biomech. 2011;44(8):1530-1535. doi: 10.1016/j.jbiomech.2011.02.141.

5. DiFelice GS, Villegas C. ACL preservation: early results of a novel arthroscopic technique of suture anchor primary ACL repair. Presented at: AANA 2015 Annual Conference; April 23-25, 2015; Los Angeles, CA. Accessed July 14, 2015.

6.DiFelice GS, DeLong JM, Villegas C. Suture Anchor vs. drill tunnel primary ACL repair: an in vitro comparison of gap formation. Presented at: ISAKOS 2015 Annual Conference; June 7-9, 2015; Lyon, France. Accessed July 14, 2015.



The views expressed in this post reflect the experience and opinions of the presenting surgeon and do not necessarily reflect those of Arthrex Inc. This technique may not be applicable to all patients.

Category: Arthrex Blog

The views expressed in these posts reflect the experience and opinions of the presenting surgeons and do not necessarily reflect those of Arthrex, Inc. This is not medical advice and Arthrex recommends that surgeons be trained in the use of any particular product before using it in surgery. A surgeon must always rely on his or her own professional clinical judgment when deciding whether to use a particular product when treating a particular patient. A surgeon must always refer to the package insert, product label and/or instructions for use before using any Arthrex product. Products may not be available in all markets because product availability is subject to the regulatory and/or medical practices in individual markets. Please contact your Arthrex representative if you have questions about availability of products in your area.