This Physician's View opinion piece is written by Sean Keyes, DO, AdventHealth for Children pediatric orthopedic surgeon.
The incidence of anterior cruciate ligament (ACL) tears, one of the most common sports injuries in pediatric patients, has increased during the last 20 years with females at higher risk, and most injuries occurring during the high school years. In the natural knee environment, the ACL is not able to heal itself because of enzymes present in the synovial fluid. As a result, the standard of care has been to try to replace the ACL through reconstruction or replacement by taking a graft either from another portion of the knee, contralateral knee, or cadaver to make a new ligament. Despite our best efforts, the results of this approach are suboptimal with re-tear rates of around 20% in children, with only 69 percent of pediatric patients able to return to sport and only 55.2 percent able to return to their previous level of play.
A Paradigm Shift — Repair of the Native ACL
After years of research and development to address the synovial fluid and enzyme limitations, we now have the first significant new treatment option for ACL tears in more than 30 years — the Bridge-Enhanced® ACL Restoration (BEAR®) Implant, a bio-engineered implant that facilitates healing of the patient’s native torn ACL. The U.S. Food and Drug Administration (FDA) granted De Novo approval of the BEAR Implant in December 2020, and it became commercially available in January 2022. AdventHealth for Children adopted this right away and became the first in Central Florida and the second in the state of Florida to perform a pediatric BEAR implant procedure.
Since then, I have completed more than 30 cases and am also actively involved in training and educating other surgeons throughout the country to use this new approach. Recently, AdventHealth was recognized for being the first center to perform 50 BEAR procedures to all ages. We remain one of only a few in the country currently offering this ACL repair option to our pediatric patients and are pleased to provide them an alternative to traditional reconstruction or replacement.
How BEAR Works — Facilitating a Healing Environment
The BEAR implant is a bovine collagen sponge that starts off hardened and when injected with autologous whole blood, softens, and forms a stable blood clot. Using a minimally invasive, single-site surgical procedure, the clot is inserted between the torn ends of the ACL, creating an environment that facilitates the body’s own healing of the native ACL by supporting cell migration and proliferation while maintaining the ACL’s original attachments to the femur and tibia. Over 6-8 weeks, the stable clot is resorbed and replaced with native cells, collagen, and blood vessels, leaving a restored, healed ACL.
BEAR is currently indicated for skeletally mature patients at least 14 years of age with a complete rupture of the ACL, as confirmed by magnetic resonance imaging (MRI). Patients must have an ACL stump of at least 1 cm attached to the tibia to facilitate the restoration. It is recommended that the BEAR device be implanted within 50 days of injury.
Benefits of BEAR ACL Repair in Pediatric Patients
There are four primary goals to ACL repair using the BEAR Implant:
- Provide a stable knee.
- Preserve and heal the native ACL.
- Prevent repeat knee injury (ACL or meniscus).
- Prevent arthritis, which is estimated to occur in 78% of people with ACL tears.
A recent study comparing the BEAR procedure to standard ACL techniques demonstrated that BEAR patients experienced the following:
- Earlier resolution of symptoms, including pain
- Increased satisfaction and confidence in their knee function as measured through International Knee Documentation Committee (IKDC) scores -- 86 points vs. 78 points at 6 months post-surgery
- Improved resolution of hamstring muscle strength
Another study comparing the two approaches found that two years after surgery, the BEAR group had a significantly higher mean hamstring muscle strength index (98.2%) compared to the traditional repair group (63.2%). Females in particular recover strength in their hamstrings and quadriceps more quickly than their male counterparts.
In addition, pre-clinical studies suggest that the BEAR Implant may reduce the rate of osteoarthritis. However, this has not yet been confirmed in human trials and is something we will continue to explore in the coming years.
By helping the native ACL heal itself, we can preserve the patient’s normal anatomy, which should provide for more natural motion and function of the knee. In addition, we do not have to create a second surgical wound site to harvest a healthy tendon from the patient, avoiding the additional insult and pain that causes. BEAR also eliminates the need for a donor tendon — another factor that can complicate healing. So far, the overall recovery time using BEAR seems to be about the same as traditional techniques — about 9 months.
As we gain more experience with BEAR, we will closely monitor the ACL re-injury rate. Currently, it appears to be in line with standard ACL techniques.
Returning Student Athletes to Sports
As a team physician for several local high schools and a father of four active, athletic kids, I know first-hand the physical, psychological and social importance of getting an injured kid back to the sport they love. With the BEAR Implant, we’re able to offer young athletes with torn ACLs a more natural solution that works with their bodies as they continue growing. In one of the most recent studies completed on a group of patients ages 13 to 35 with torn ACLs, approximately 88% of those treated with the BEAR implant had been cleared for return to sport at 1 year after surgery compared to 76% in the standard ACL repair group.
The best part of my job is seeing adolescent athletes get back on the field with a smile on their face. When they come in for their follow-up visit with a video of them scoring a goal, that’s what it’s all about.
Looking Ahead — Research on the BEAR Implant Continues
Additional research studies on BEAR continue, including the following:
- The BEAR III Trial for Bridge-Enhanced ACL (Anterior Cruciate Ligament) Restoration — exploring use of the BEAR implant for partial tear repair as well as the potential to expand the criteria down to age 12
- A Comparison of ACL Repair with BEAR Device vs. Autograft Patellar Tendon ACL Reconstruction (BEAR-MOON) — further evaluating the effectiveness of the BEAR implant, including for higher-level athletes
- BRIDGE Registry – ongoing monitoring of the BEAR implant for outcomes and surgical variations
I truly believe this revolutionary approach could be a game-changer in the worlds of pediatric orthopedic care and sports medicine. The National Football League Players Association (NFLPA) is just one of many professional sports organizations interested in the effectiveness of the BEAR implant in treating ACL injuries and has sponsored many of the clinical trials.
To refer a pediatric patient consideration for BEAR ACL repair, click here.
