Injured Your ACL? Here’s What You Need to Know.

Meet the Experts

For many athletes, the anterior cruciate ligament, or ACL, is a rubbery band of terror best known for its potential to fail under strain and ruin a season — or even end a career. Anatomically, this ligament tucks deep in the center of the knee joint and connects the thigh bone to the shin bone. It stabilizes the knee as it bends and rotates. That role, unfortunately, also makes it vulnerable to sharp pivots and sudden lateral forces that can cause it to tear or snap, leaving the knee loose and unstable.

Traditionally, most ACL injuries require reconstruction of the ligament with a tendon from a donor or the patient’s own body. Although, rapid advances are making it increasingly possible to repair a patient’s existing tendon rather than reconstructing it.

If you’ve injured your ACL, here are four things to know, according to top orthopedic surgeons within the Department of Orthopedic Surgery at NYU Langone Health, ranked No. 3 in the nation, according to the 2023–24 rankings from U.S. News & World Report.

1) For repairs, timing matters.

For reasons still not fully understood, the fluid surrounding the ACL seems to interfere with its ideal healing. If the goal is to repair your existing ACL, the sooner you fix it the better. “Within two to three weeks, the tissue may be repairable,” says NYU Langone orthopedic surgeon Guillem Gonzalez-Lomas, MD. “But not long after that, the ligament will retract and scar.”

In Gonzalez-Lomas’s practice, less than 10 percent of ACL injuries qualify for a repair, where the existing ligament is physically reattached to the bone it tore from and reinforced with high tensile-strength sutures. Tears directly off the femur are better candidates for repairs since the ligament can be more securely reattached to the bone.

A new biological implant approved by the FDA in 2022 called the BEAR — Bridge Enhanced ACL Repair — may augment the healing environment. The implant is a spongy cylinder of collagen derived from cows. About the size of two stacked marshmallows, it’s saturated with the patient’s own blood prior to implantation; this, in theory, primes the fluid surrounding the ACL for healing. “There are a lot of benefits to being able to keep your own tissue, but the implant isn’t a slam dunk just yet,” notes Gonzalez-Lomas, who has performed several repair procedures using the BEAR.

The strength of the repaired ligament over time is still unknown. “We’re waiting to see the long-term data,” he says.

In some cases, the early recovery period after a BEAR implant can be more restrictive than it is for an ACL reconstruction, with patients typically required to avoid any weight-bearing on the knee for at least four weeks. “The implant is currently marketed for any kind of ACL tear, but I’m very judicious in my selection process,” notes Gonzalez-Lomas. “For me, the ideal patient has recently torn their ACL, specifically off the femur bone, with ample remaining ligament tissue. And they’re fully committed to scrupulously following their rehabilitation regimen.”

2) Your ACL may be beyond repair, but a reconstruction is often more durable.

Most serious ACL injuries that cause knee instability and pain require reconstruction surgery, but it all depends on the patient. Orthopedic surgeons at NYU Langone consider the severity of the injury, its location, any collateral damage within the knee, your age, your overall health, and your activity level, among other factors. “We often see full ruptures in which the ligament gets overstretched like a rubber band and eventually pops,” explains orthopedic surgeon Abigail L. Campbell, MD, director of the Center for Women’s Sports Medicine.

“In these cases, the standard approach is a reconstruction surgery, where the ligament is replaced,” she says. “An overstretched ligament will be permanently deformed.” During a reconstruction procedure, the surgeon makes a small incision in the knee to remove the injured ligament.

Typically, if you’re under 30 years old, the surgeon will replace your damaged ligament with a tendon graft taken from your patellar tendon, hamstring, or quadriceps tendon. The new tendon is then threaded through holes tunneled in your thigh and shin bones and secured in place with screws.

An estimated 90 percent of athletes who’ve undergone an ACL reconstruction at NYU Langone and adhered to the physical therapy regimen heal well enough to return to their sport.

3) Find a surgeon who treats you, not just your MRI.

Every ACL injury is unique. “Not every patient has the exact same injury or the exact same goals,” says Campbell. “When we evaluate a patient, we’re examining the knee, yes, but we’re also trying to understand the patient’s goals and lifestyle, rather than just looking at an MRI and applying the same surgery every time.”

Is your goal to garden and walk without pain? Or is to return to playing professional soccer or hockey? Your personal demographics and ambitions are critical in helping a physician assess your treatment options.

For example, female athletes are up to eight times more likely to injure their ACL due to a combination of mechanical and hormonal differences that can make the ligament more vulnerable. “I treat bones and joints, but these are attached to a whole-body human being,” says Campbell. “There are specific factors you need to consider when treating female patients in general — things like hormonal changes at any age, menopause, bone density, and the risk of osteoporosis. Being connected to other specialists at the Center for Women’s Sports Medicine, a multidisciplinary hub, can make all the difference.”

4) Your physical therapist will be your new best friend.

Your rehab regimen is one of the biggest predictors of a successful outcome. “The relationship that the patient has with their physical therapist is arguably more important than the one they have with their surgeon,” notes Campbell. “I see a patient once every three months, but a physical therapist can see the patient for 12 months straight.”

Orthopedic patients at NYU Langone are referred to NYU Langone’s Rusk Rehabilitation, consistently ranked the No. 1 rehabilitation program in New York and one of the top five in the country by U.S. News & World Report. At Rusk, patients have the benefit of top-trained physical therapists and state-of- the-art technology at the Sports Performance Center, where they receive the highest quality evaluation for returning to sport.

“There’s a very specific set of criteria involving qualitative and quantitative factors for assessing an athlete’s readiness to return to sport,” notes Campbell. “It can be difficult to find a center that offers this comprehensive return-to-play testing, but this is available with the sports-trained physiotherapists at Rusk.”

UPDATED: The Sports Health experts at NYU Langone have the multi-specialty expertise to provide coordinated, comprehensive care for all types of athletes. As an official healthcare partner, Life Time can offer its members exclusive direct and easy access to NYU Langone’s world-class orthopedic specialists and performance experts, who can help you meet your health and fitness goals. To schedule an in-person appointment or video visit with a Sports Health expert, visit https://nyulangone.org/care-services/sports-health/request-appointment-lifetime.