ACL injuries are common in sports, but they seem to be particularly common in women’s and girls soccer. The American Medical Society for Sports Medicine says, “ACL tears occur in both genders, but female athletes are at higher risk with college basketball and soccer female athletes having a threefold higher risk than their male counterparts. The effect of this discrepancy has been amplified in the past few decades as a result of the passage of Title IX in 1972 resulting in large increases in female athletes participation and participation at higher levels of competition.”

The reasons for the discrepancy in ACL injuries varies, including hormones. “There is evidence that high levels of estrogen can increase ligament laxity, and that increased laxity is associated with ACL tears,” says Stephen Silver, MD, orthopedic surgeon at Hackensack University Medical Center, who has done research on the subject. “Another theory, after puberty women’s quadricep muscles continue to strengthen, while their hamstrings typically stay the same. This creates a muscle imbalance that leads to ACL tear.” Both theories are bolstered by the numbers that before puberty ACL tears are rare, but after puberty a women’s risk of an ACL tear increases significantly. 

The anatomy and reasoning behind injuries in female athletes hasn’t been studied the same way men’s injuries have been studied. The New York Times notes European soccer’s governing body, UEFA, has been conducting an injury surveillance study on men’s soccer for more than two decades. The women’s equivalent has been operating for only five years.

When it comes to preventing ACL tears, training is important. This involves plyometric stretching (jumping), agility, balance, and strength training. The goal is to decrease the tendency for high-risk movement patterns by teaching proper alignment of the knee and hip while landing and cutting. Core strength is also a significant piece of the puzzle. 

New Treatment for ACL Tears

ACL is the most common ruptured ligament in sports, but the surgical reconstruction, which has been performed routinely for four decades, offers a 95% success rate. While this represents an overall positive outcome, a growing body of evidence now supports making a shift to include the Lateral Extra-articular Tenodesis (LET) procedure with ACL reconstruction for a small patient subgroup, including young female athletes, with the potential to cut their ACL graft failure rates by two-thirds.

Stephen Silver, M.D., chief of the Department of Sports Medicine at Hackensack Meridian Hackensack University Medical Center, has observed in his own practice, and in literature and medical conference activity, that the significant potential of combining the LET and ACL procedures for a subgroup of patients reduces failure rates to one-third of ACL reconstruction alone for this group.

Qualifying patients include females, under age 30 in particular, who are five times more likely than men to experience failure of a reconstructed ACL. The group also includes high-level athletes and individuals with loose, unstable joints, knock knees, or a meniscus tear. A procedure such as this could have potentially prevented repeated ACL that injuries players like Megan Rapinoe suffered.

When a patient suffers an ACL tear, Hackensack Meridian Health is now also offering a new and innovative treatment. In May, orthopedic surgeons at Hackensack University Medical Center performed the Bridge Enhanced ACL Restoration (BEAR) Implant operation to reconstruct the injured knee ligament of a 15-year-old soccer player. The BEAR Implant is a treatment that promotes the body’s own healing processes to join the ends of a torn anterior cruciate ligament (ACL), one of the most common sports injuries.

“The BEAR Implant is the first device developed to help a person’s ACL to heal on its own,” explains Hackensack University Medical Center orthopedic surgeon Amit Merchant, MD, who performed this procedure as well as a second BEAR operation with orthopedic surgeon Yair David Kissin, MD. “This approach offers an alternative to conventional ACL reconstruction which uses a tendon from another part of the patient’s body. That can leave a patient with pain where the tendon was retrieved.” Such “autografts” are usually tissue taken from the patellar tendon, quadriceps tendon, or hamstring. 

The patient, Kelis Guzman, is a 10th grader from Hasbrouck Heights, New Jersey, who plays on the New Jersey Crush Girl Academy-level soccer team as well as in the Elite Clubs National League (ECNL)—a more intense level of play. At an exhibition game in February, after executing a side tackle, she felt her left knee pop and click when she stood up. “It wasn’t painful, but it felt very unstable,” she recalls. “Something was definitely wrong.” She sat out the rest of the game, believing it might be a muscle sprain. 

A visit to a local emergency room showed nothing suspicious on an x-ray, so the doctor sent her home. After a few days, it hurt to flex her leg and she had limited range of motion. Her mother, Karin—a patient access specialist at Hackensack University Medical Center—took her to see Merchant, who had treated Kelis in 2021 for a broken ankle. An MRI confirmed she had torn her ACL.

Her options included two to three months of physical therapy, but without surgical treatment, she would need to wear a brace every time she played soccer—something she was not interested in doing. Then Merchant told her about the BEAR Implant. “I thought it sounded super cool,” says Kelis. She didn’t like the idea of traditional ACL reconstruction, which would have been done using a piece of her own patellar tendon, and she wanted to do all she could to increase her chance of playing Division 1 soccer in college.

The synovial fluid that acts as a lubricant in the knee also prevents the formation of blood clots that are vital for healing, so a torn ACL will not heal by itself. BEAR is a spongy collagen implant that is infused with a patient’s blood. The surgeon positions it between the two torn ends of a ruptured ACL during arthroscopic outpatient surgery. The implant is designed to hold and protect the patient’s blood in the gap between the ends of the ACL and promotes the formation of a clot. Within eight weeks, the BEAR Implant is resorbed and replaced with a person’s natural cells, collagen, and blood vessels. The new tissue continues to rebuild itself and strengthen over time.

During Kelis’ operation, the surgical team removed a small sample of her blood while she was in the operating room. Working through very small incisions, Merchant first sutured the torn ends of her injured ACL. He then saturated the BEAR Implant with her blood and positioned it within the gap. She went home the same day using crutches and was able to put weight on her left leg. She started physical therapy a week later and within six weeks was up to three weekly sessions. Her range of motion is returning well, and she should be able to go back to playing soccer by December, having allowed her body and the BEAR Implant to heal her injured ACL. 

“I feel pretty good knowing I’ll have my own ACL back,” notes Kelis, who would like to pursue a career in healthcare. “It was really cool learning about this innovative procedure. I’m so grateful I was able to have it and that it will let me get back to my sport.”

In addition to promoting natural healing, the BEAR Implant operation does not involve removing the nerve endings in the ACL that give an athlete proprioception—the ability to feel where one is moving in space, and a critical aspect of preventing injury. Conventional ACL reconstruction using an autograft removes the original ACL nerve endings and may reduce proprioception, so leaving those nerves in place could potentially give an athlete a better sense of how to move efficiently to prevent injury.

“This technique is a way to restore a patient’s native ACL. It’s not just sewing two ends of the ligament back together, but rejuvenating the healing process and getting a patient back to 100%,” adds Merchant. “The BEAR Implant is another example of our leadership in orthopedics and our commitment to offering the most advanced treatments to the people of New Jersey and surrounding areas.”

The BEAR Implant is indicated for people with a torn ACL who are skeletally mature (bones have stopped growing).