It can happen in an instant: you land the wrong way on the soccer field or even while stepping off the curb, and — pop! — the ligament inside your knee tears. An injury to the anterior cruciate ligament, or ACL as it’s more commonly known, can cause lifelong knee instability if not corrected.
Women are much more likely to tear their ACLs: About one in 29 female athletes and one in 50 male athletes will injure their ACL at some point, said Dan Enz, PT, LAT, SCS, a physical therapist with UW Health Sports Rehabilitation. The risk is even higher for those who participate in multi-directional sports, including basketball, soccer, football, lacrosse and downhill skiing.
“ACL tears are very common, and you can injure your ACL doing any number of things,” said Andrea Spiker, MD, a UW Health orthopedic surgeon. “It happens when you plant the foot and pivot the leg, so your foot stays put but your body twists around it. That puts tension on the ACL and tears it. So people can even tear their ACL getting up from the couch or stepping off a curb — that little jolt can be enough to do it. But usually we see ACL injuries with younger, active people who play higher-energy sports.”
Caring for your ACL before and after injury
Here’s what to know about how to care for your ACL before and after an injury:
If you have knee pain, get it checked out
“Sometimes we see patients who’ve had a chronic ACL tear and they never knew it,” Spiker said. That’s especially common when the injury occurred during an everyday, low-impact activity.
Women face higher risk
“Women and girls are much more likely to tear their ACLs, especially in high-risk sports like soccer," Spiker said. "We don’t know exactly why, but we think it’s because females have a broader pelvis, so their knees are in different alignment. And because of hormonal fluctuations, we think that ligaments are more at risk of rupture at certain times of the month."
Consider a prevention program
Agility and strength training, particularly strengthening the hip abductor and quadriceps muscles, can help prevent ACL injuries.
“We’re finding that there are more modifiable risk factors that can lead to ACL injuries,” Enz said. “It’s been shown in research that if you train athletes to move in a certain way, you can reduce their risk for ACL tears. You can learn to land, cut and pivot while keeping the knee in line with the hip and ankle, and also absorb force correctly by bending at the ankle, knee and hip, because that’s putting force through the muscular system instead of the bone system.”
Understand your surgical options
Surgeons can’t just sew a torn ACL back together, so they reconstruct it using different tissue from either a cadaver or the patient’s own tendon. “Through arthroscopy and a small incision, we insert and fix the graft in place with screws or tension buttons,” Spiker said.
But not every torn ACL requires surgery. Patients who tear their ACL during low-impact activities and aren’t looking to resume high-impact athletics can be good candidates for non-operative treatment.
“In some patients, ACL tissue can tear and heal in a position that’s almost anatomic, and that scar tissue provides enough stability for their knee that their knee function is near normal,” Spiker said. “It depends on the mechanism of the tear, the patient’s level of activity and what they want to go back to and the findings of the clinical examination. If I see that their knee is not that loose and they can do the things they want to do, like run or bike, with no episodes of instability, then they may not need surgery.”
Know the risks of postponing surgery
“The reasons we suggest patients get an ACL reconstruction is because we know it’s a very important stabilizer of the knee,” Spiker said. “Abnormal movement after an injury can shear off cartilage and lead to arthritis, and that can cause pain and dysfunction and ultimately the need for a total knee replacement.”
Once you’ve lost too much cartilage, it’s irreversible and ACL reconstruction is no longer an option.
Start PT early and stick with it
If you do need surgery, physical therapy starts even before surgery to decrease swelling, which improves stiffness and complications afterward.
“Better strength before surgery equals better outcomes after surgery. We’re trying to restore motion and strength as much as possible,” Enz said.
After surgery, you’ll resume physical therapy to reduce swelling again, then work on motion and mobility, building your way up from walking without a knee brace to eventually running, cutting and pivoting. If you decide not to have surgery, your physical therapist will also help you work on mobility, strength and neuromuscular control.
“Ligaments are rich in receptors that communicate to the brain about where you are in space, and when you lose the ligaments, it can affect your neuromuscular control,” Enz said.
Your physical therapist will also teach you injury prevention techniques.
Be patient during recovery
You might feel good early on after surgery, but that doesn’t mean that your knee is ready for high-impact activities.
“The rehab process has evolved over the years,” Spiker said. “We used to send patients back to sports after six months, but then people were returning with injuries not only on the operative side but also the non-operative side. The healing process takes months and months longer than we expected.”
Recent research shows that waiting nine months before returning to a sport after surgery instead of just six months can dramatically reduce your chances of re-injury — decreasing your risk by 51 percent, Enz said.
But everyone’s recovery is different, and it’s not just a matter of time on the calendar. “We do post-operative progressive testing, so time after surgery matters but how you’re functioning matters as well,” he said.
Prepare for the possibility of future injuries
“If you tore your ACL once, you already have some inherited risk, whether it’s movement patterns or your anatomy or the sport you do, so the art of the therapy is figuring out which risks are modifiable and how can we reduce them,” Enz said.
Even two years after surgery, some patients still aren’t fully recovered and tend to put more force on the non-injured leg. “They’re much more likely to tear their other side because they’re still favoring their injured leg,” he said.
But if you take it slow and do what you can to lower your modifiable risks, you can safely get back to an active lifestyle.