Surgeons dissect the changing face of ACL treatment
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In ACL treatment, ACL reconstruction has long been the gold standard. However, recent innovations and research regarding ACL repair have surgeons wondering if a changing of the guard could be on the horizon.
In an interview with Healio | Orthopedics Today, Brett D. Owens, MD, professor and vice chair of academic affairs in the department of orthopedic surgery at the Warren Alpert Medical School of Brown University, said primary repair research “is the ‘holy grail’ of sports medicine.”
Source: Kevin Shinsako, MS, PA-C
“To be able to repair the ACL successfully, avoiding the need for a graft, is something that we have all been striving for, for half a century,” Owens, who is a Healio | Orthopedics Today Editorial Board Member, said. “We continue to make significant gains in this regard, and it is exciting.”
According to Rachel M. Frank, MD, associate professor in the department of orthopedic surgery and the director of the Joint Preservation Program at the University of Colorado School of Medicine, “recent interest is namely due to the fact that we have recognized which tear patterns are most appropriate for repair, and we have narrowed down how to do the repair from a technical and biologic aspect.”
Renewed interest in ACL repair
Recent interest in ACL repair also has grown due to the elimination of donor-site morbidity from harvesting grafts, according to Owens.
“The primary advantage is the avoidance of the morbidity of a graft harvest,” Owens said. “That is half the surgery, but that is half the pain and recovery from an ACL surgery. Whether it is a hamstring graft, a patellar tendon graft or a quad graft, there is significant donor site morbidity associated with that: temporary pain, weakness and a whole host of complications. Avoiding that is huge.”
Aaron J. Krych, MD, professor of orthopedic surgery at the Mayo Clinic, said there are additional theoretical benefits related to ACL repair, including maintaining proprioception, avoiding socket placements and a potentially quicker rehabilitation process.
In addition, Seth L. Sherman, MD, associate professor of orthopedic surgery and fellowship director in the division of sports medicine at Stanford University, said ACL repair is intriguing, particularly if proven to mitigate both short- and long-term sequalae of ACL injury and graft reconstruction.
“By preserving native tissue and proprioception, the goal ultimately would be not only a safe and expedient return to sport, but reduction of the relative risk over time of knee osteoarthritis, which is an unsolved issue,” Sherman, who is a Healio | Orthopedics Today Editorial Board Member, said.
Alternative treatment methods
Another reason for the recent reevaluation of ACL repair is the development of alternative treatment methods, like the Bridge Enhanced ACL Repair (BEAR) procedure.
The procedure involves placing a denatured collagen-based sponge (Miach Orthopaedics) from a xenograft source between the ACL stump and the femoral footprint.
Researchers are conducting the BEAR-MOON trial, which is a multicenter, randomized controlled trial comparing the BEAR procedure to traditional ACL reconstruction with a patellar tendon graft in 200 patients aged 18 to 55 years with an ACL tear.
Owens, who is a researcher involved in the trial, said the trial will hopefully provide surgeons who treat ACL injuries with more research and another potential avenue for ACL repair.
“[The BEAR-MOON trial] will be a huge indicator as to how [the BEAR procedure] is received in the general population,” Owens said. “Right now, it is still being utilized among early adopters, and a lot of people are on the sidelines waiting to see how it works out.”
Krych said he believes emerging data, like those coming from the BEAR-MOON trial, could serve as a catalyst for ACL repair.
“When orthopedic surgeons assess the outcomes of well-performed studies, they have the potential to immediately change their clinical practice,” Krych said. “All eyes are on the BEAR-MOON trial, which is one of those well-designed studies ... I think the orthopedic community is looking forward to what those results will be because the earlier studies on ACL repair were designed to assess noninferiority, but any significantly positive outcomes could generate more momentum for ACL repair overall, not just with the BEAR implant procedure.”
More questions than answers
However, while there is growing optimism about the future of ACL repair, Sherman told Healio | Orthopedics Today that recent ACL repair data leave more questions than answers, and surgeons should remain cautious.
“I think we have more tools in the toolbox and some real promise for the future,” Sherman said. “But I do not think that we should [implement repair] just because we are hopeful that these biologic and biomechanical tools can fill gaps. That is not sufficient. I think we need to practice evidence-based medicine and prove that they are the same or better before we advocate for mass adoption.”
In addition, Frank said that surgeons should be cautious of new products, as well as the general push from industry to adopt alternative treatment methods.
“Surgeons need to be appropriately cautious with using novel products to repair ACL tears,” Frank told Healio | Orthopedics Today. “This is an area where industry is pushing the limits of what can be repaired and it becomes attractive to both surgeons and patients to go ahead and push those limits too, but we have to be cautious.”
Likewise, Jorge Chahla, MD, PhD, associate professor of orthopedics, director of biomechanics research and director of the International Fellowship Program at Rush University Medical Center, said there remains to be a great deal of skepticism about ACL repair due to a lack of comparative data.
“There have not been any large, randomized clinical trials comparing repairs vs. reconstruction in a blinded fashion,” Chahla said. “The data that we have so far are not fully conclusive, mainly on the long-term success of this technique and if there is a specific subset of people in which this should be indicated.”
In addition, Frank said more “self-critical” data will need to be published before ACL repair can be more widely adopted.
“We have to be willing to report on failures, so that we can educate ourselves, our colleagues and the product teams on the industry side on what is working and what is not working,” Frank said. “Ultimately, we want to do what is in the best interest of our patients, and not every ACL tear is amenable to primary repair.”
Treatment of high-level athletes
According to Owens, one major hurdle to the implementation of ACL repair on a wider scale and range of populations is the risk associated with higher-level athletes.
“Certainly, one population that remains to be seen with some of these newer techniques is the high-level college and professional cutting and collision athlete,” Owens said. “That remains to be seen, but like many new technologies, all it sometimes can take is that one high-profile professional athlete, and then everyone wants it.”
Chahla said there is not enough evidence that ACL repair can reconstitute the tissue and last for extended periods of time.
“Therefore, attempting these repairs that have a higher likelihood of failing than an ACL reconstruction in the highest-risk population is maybe too much to ask,” Chahla told Healio | Orthopedics Today.
Sherman also said outcomes with ACL repair would have to prove to be superior to ACL reconstruction for it to be adopted in the treatment of higher-level athletes.
“I think in scenarios where the stakes are extraordinarily high, it is going to take superiority,” Sherman said. “If it is equivalence, then it has to be as easy or easier and as cheap or cheaper. If it is superior, then it can be whatever it needs to be to get the job done.”
Listen to the athlete
Another barrier to the widespread implementation of ACL repair is the risk associated with performing a new procedure on higher-level athletes.
“Until a consortium of surgeons who treat high activity and/or elite athletes study this in comparison to our gold standard, I cannot take a leap of faith and say to my elite athletes that I can predictably and reliably repair your ACL, cut your time, get you back faster with lower risk of recurrence and no significant risk of OA,” Sherman said.
In the end, surgeons should listen to athletes for which treatment they would like to undergo, and not treat them any differently than any other patient, according to Frank.
“The way I handle this, and the way I recommend handling this, is to try to treat your athletes, whether they are professional, collegiate, high school, weekend-warrior or anyone in between, all the same,” Frank, who is a Healio | Orthopedics Today Editorial Board Member, said. “Try to not do anything special for the professional athlete because that is when you stretch your indications. That is when mistakes get made. Try to do the best possible job for every athlete in front of you.”
Reconstruction remains the standard
Despite recent trials and developments regarding ACL repair, Sherman said ACL reconstruction remains the gold standard.
Source: Rachel M. Frank, MD
“ACL reconstruction, in my mind, still is the gold standard when you require surgical management of the ligament,” Sherman said.
However, there are several gaps in ACL reconstruction that could potentially be rectified with an improved ACL treatment option, according to Sherman.
“We do not think that we have solved arthritis and we do not think that we can get these people back quickly,” Sherman said. “There are gaps here in what ACL reconstruction, even the best type in the best hands, can do. We are trying to exploit that gap by harnessing the power of biology and biomechanics to achieve things that we have not achieved.”
Although Chahla said recent biological and mechanical research for ACL repair may improve outcomes and lead to better selection of patients, he added it could be difficult to persuade surgeons to step away from ACL reconstruction in favor of a new treatment method.
“[ACL repair] has been studied in the past, and the results have been less than optimal with high failure rates,” Chahla said. “In order to leave something that is working already, you have to show compelling data from multiple groups that have validated the data and shown that it is a viable, long-term operation.”
Combination of biologics, mechanics
According to Frank, neither a singular biological nor mechanical component alone can produce the most successful version of ACL treatment. Instead, she said the future of ACL treatment will have to be more nuanced.
“The next wave of all sports medicine repair and reconstructive procedures is likely going to rely on a scaffold or tissue engineering construct combined with a biologic construct,” Frank said. “The key is trying to figure out how to convince the body’s tissue to heal as an appropriate tissue.”
In addition, Frank said the combination of biological and mechanical advancements could improve specific musculoskeletal tissue, which is another hole in current ACL treatment.
“This is where concepts such as scaffolding, tissue engineering and regenerative constructs come into play. If we can marry all of that together combined with appropriate surgical indications, that is when we are going to have the ‘holy grail’ of sports medicine,” Frank said. “It will not just be applicable to the ACL. It will be applicable to the rotator cuff, meniscus, tendons, ligaments, bones, cartilage, etc. It will be applicable everywhere around the body.”
Individualize treatment
Regardless of repair optimism levels, the dynamic nature of ACL treatment seems to be acknowledged by nearly every surgeon, according to Krych.
“Gone are the days of a one-size-fits-all approach to every patient,” Krych told Healio | Orthopedics Today. “An ACL surgeon today needs to make evidence-based decisions for each individual athlete they treat, and that requires having an entire toolbox at their disposal, including ACL repair, and be able to perform [surgery with] multiple grafts: hamstring, quadriceps and patellar tendon.”
Frank said orthopedic surgeons need to continue to individualize the ACL treatment process and choose the correct patients for the correct treatment methods to ensure future success.
“I think over the next 10 to 15 years, what we are going to see is an explosion of biologic and regenerative abilities where we can tailor the treatment to the patient and their specific ACL tear pattern,” Frank said. “That is going to require not only improvements in our materials, in our implants, but also in our regenerative and biologic treatments. We are well on our way to doing that.”
Frank continued, “When it comes to picking the right patient for repair vs. reconstruction, no matter what, making sure your patients are aware that both are possibilities and making the right decision for your patient is of the utmost importance.”
Sherman added that individualizing ACL treatment will require a more holistic approach to the treatment process.
“The key point for individualized ACL surgery is that it is not just about the ACL. It is about the patient, their demands and the other structures in the knee,” Sherman said. “It is about the meniscus, it is about the alignment, it is about the tibial slope, it is about their underlying joint laxity and it is about the secondary restraints. We cannot tunnel vision on graft choice or on repair vs. reconstruction. We need to broaden and treat the whole patient to achieve the optimal outcomes that we want in the future.”
- References:
- Cao, Y, et al. Orthop Traumatol Surg Res. 2022; doi:10.1016/j.otsr.2022.103227.
- Murray MM, et al. J Orthop Res. 2007; doi:10.1002/jor.20367.
- Murray MM, et al. Am J Sports Med. 2020; doi:10.1177/0363546520913532.
- What is BEAR-MOON? https://bearmoon.org/trial.php. Accessed June 16, 2023.
- For more information:
- Jorge Chahla, MD, PhD, of Rush University Medical Center, can be reached at jorge.chahla@rushortho.com; Website: jorgechahlamd.com.
- Rachel M. Frank, MD, of the University of Colorado School of Medicine, can be reached at rachel.frank@cuanschutz.edu.
- Aaron J. Krych, MD, of the Mayo Clinic, can be reached at madson.rhoda@mayo.edu.
- Brett D. Owens, MD, of the Warren Alpert Medical School of Brown University, can be reached at owensbrett@gmail.com.
- Seth L. Sherman, MD, of Stanford University, can be reached at dr.seth.sherman@gmail.com.
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