Do alternative implants offer compelling data regarding their use in ACL treatment?
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Data are on the way
There are two questions here. The first is the term “implant” and the second is compelling data.
If implants are considered, these are only temporary since the ACL torn ligament or ACL graft reconstruction must heal for function and stability of the knee. There is litany in history of failed implants alone or as augmentation when assessed at 5 to 10 years. In attempts at repair of a torn ACL, the BEAR implant has demonstrated functional healing of the ACL in a randomized controlled clinical trial at 2 years.
By compelling data, this means randomized controlled trials and prospective cohorts to document efficacy, safety and the personalized treatment based on individual patient and injury factors. Therefore, when a surgeon is confronted with options for new implants for ACL repair, they should ask themselves three questions:
- What is the best evidenced-based literature?
- What are the patient’s expectations and risk tolerance?
- What is your personal experience or experience of trusted colleagues with patients like them and a particular implant technique?
To my knowledge, there are compelling data in ACL reconstruction in the high school- and college-age group by avoiding use of allograft, adding an extraarticular procedure in hamstring ACL reconstructions and a risk calculator in choosing between patellar tendon vs. hamstring graft. If the patient with an ACL injury is in their mid-twenties and no longer competing aggressively as a competitive athlete, then all autografts and even allografts provide similar patient-reported outcomes and failure rates within a few percent of each other.
I am unaware of randomized controlled trials or prospective cohorts for most implants for ACL tears. Perhaps at the American Orthopaedic Society for Sports Medicine Annual Meeting some compelling data will be presented. Thus, BEAR meets the expectations of evidence for use in patients with an ACL injury, in my opinion, in an age group where graft choice has not been shown to be a differentiator of outcome. Currently, we are running a noninferiority randomized controlled trial (BEAR-MOON) between autograft patellar tendon vs. the BEAR implant at six centers where a comprehensive evaluation can be made between these two options. The evidence will ideally be more generalizable to the ACL tear population and provide data for the individual surgeon and patient for shared decision-making.
- Reference:
- Murray MM, et al. Am J Sports Med. 2020;doi:10.1177/0363546520913532.
Kurt P. Spindler, MD, is the director of research and outcomes at Cleveland Clinic Florida in Port St. Lucie, Florida.
Repair is not ready
ACL injuries in athletes are a common and potentially debilitating problem. The incidence of these injuries follows a pattern of clustering in different cycles. At the moment, there is significant cluster, especially in female athletes, with respect to noncontact injuries. In recent years, the surgical approaches, with respect to autograft reconstruction, have been successful when returning high-level athletes to competitive sport in the short-term. That said, the potential of OA in the long-term remains.
In recent years the concept of ACL repair has been developed and studied by Martha Murray, MD, and others with respect to the BEAR procedure, a biologic enhancement of an ACL repair. Although this technique has gained popularity, the published rate of re-rupture at 14% in relationship to 6% for ACL reconstruction is too high and unacceptable, in my view, in an athletic population. Furthermore, Gregory S. DiFelice, MD, has presented and published a 37% re-rupture rate in the re-rupture rate in athleteic patients younger than 22 years. In addition, Riley J. Williams III, MD, and colleagues have published a 33% reoperation rate for ACL repair in Arthroscopy.
As sports physicians, our goal should be prevention of ACL injury, prevention of subsequent ACL re-rupture and OA. The concepts and utilization of ACL repair has been shown to be inferior to autograft reconstructive options with respect to re-rupture rate. In the future, in a stepwise fashion, there may be further refinements and additional adjunctive interventions that may facilitate ACL repair. These may include concomitant anterolateral ligament reconstruction or hybrid techniques that utilize autograft or allograft to facilitate repair. At this moment, based on current evidence-based studies, ACL repair techniques are not ready for use in the athlete, but can and should be utilized in low-level recreational and older populations in which risk rates and consequences are lower.
- References:
- Meister M, et al. Knee Surg Sports Traumatol Arthrosc. 2018;doi:10.1007/s00167-017-4726-0.
- Murray MM, et al. Am J Sports Med. 2020;doi:10.1177/0363546520913532.
- Nwachukwu BU, et al. Arthroscopy. 2019;doi:10.1016/j.arthro.2019.04.005.
Bert R. Mandelbaum, MD, is a professor in the department of orthopedic surgery at Cedars Sinai in Santa Monica, California.
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