Sports’ No. 1 Nemesis: ACL Injuries

May 18, 2009
Share this story:
Girls' soccer is a sport beset by ACL injuries because of all the twisting, darting and cutting that the sport demands.

Girls’ soccer is a sport beset by ACL injuries because of all the twisting, darting and cutting that the sport demands.

“It’s the No. 1 nemesis of an athlete,” said La Verne’s Rick Rossman, MS, PT, and Administrative Director of Pomona Valley Medical Center’s Sports Medicine Center. “Except for catastrophic injuries to head and spine, an ACL tear is the injury athlete’s greatest fear because in spite of all the technological advances, it still puts them on the bench for six to 12 months, and they lose a entire sports season, which when you’re a young athlete is a lifetime.”

Tearing the anterior cruciate ligament, or ACL, has ended the athletic careers of great NFL players like Gayle Sayers and Joe Namath. More recently, ACL injuries to Tiger Woods and New England Patriots quarterback Tom Brady have kept this particular sports scourge in the news. Just as often, if not more so, ACL victims are children, some as young as 10, robbed of competing during their Little League, National Junior Basketball or AYSO soccer seasons.

The psychological impact of an ACL injury can be just as devastating as the physical trauma. “Imagine you’re a high school athlete taken out of your social circle,” Rossman said. “Now you’re no longer traveling with your team. You’re no longer part of the rallies. What do you do in the afternoons? Sports have been your whole life, and now you’re on the sidelines watching.

“That’s tough because you don’t hang with the guys in your chemistry class; you hang out with your teammates. That’s just the way it is.”

In the four part series that begins today, LaVerneOnline looks at 1) how and why ACL injuries occur; 2) what treatment options are available (Surgery, yes or no?); 3) rehabilitation and recovery; and 4) prevention.

With Rossman’s and the Sports Medicine Center’s long experience and expertise in this field, we’ll try to guide you and get you the facts about ACL injuries, treatment options, rehab regimens and prevention strategies.

“Can you return to your sport and make a full recovery,” Rossman asked rhetorically. “Yes, 100%,” he said.

“Is your knee the way it was when you were born?


Part I: How and why do ACL injuries occur?

To understand an ACL injury, it helps to know a little about how the knee works.

The knee is the large joint where the shinbone (tibia) meets the thighbone (femur).  Two ligaments run along either side of the knee. The medial collateral ligament (MCL) is on the inside and keeps the knee from bending in. The lateral collateral ligament (LCL) is on the outside and keeps the knee from bending out.

Two other ligaments — the ACL and the posterior cruciate ligament (PCL) — cross each other in the middle of the knee. They work together to keep the shinbone attached to the thighbone.

The ACL connects the front part of the shinbone to the back part of the thighbone so that the shinbone does not slide in front of the thighbone. “The ACL is the main stabilizing ligament of the knee,” Rossman explained. “It prevents your shin bone from sliding out from under your knee bone.”

This critical stabilizing ligament is not flexible. “It’s like a leather strap,” Rossman said. “It doesn’t have a lot of give.”

When the knee is forced into an abnormal position – from extensive pivoting, darting, cutting, weaving, twisting or jumping and landing awkwardly — the ACL and other ligaments can tear, partially or all the way. Stop-and-go sports like football, soccer, basketball, baseball and volleyball where the athlete plants and pivots, jumps and lands, and accelerates and decelerates in short explosive bursts, inordinately tax the knee and stress the ligament.

A Non-Contact Injury

“About 80% of the time the injury is actually a non-collision event,” Rossman said. “You always think of a big blow out – somebody receiving a nasty blow to the side of the knee, where you tear multiple knee ligaments and cartilage. These occur, but rarely compared to the non-contact tears. Typically, the athlete hears and feels a pop, and because the ACL has a blood vessel that runs through it, the blood starts leaking inside the knee joint causing immediate and dramatic swelling,” Rossman said.

When an ACL injury occurs, the knee becomes less stable. When the knee is unstable, patients often complain of a sensation of excess movement in the knee and a feeling it will “give out” from under them, that is, it buckles unexpectedly. Sometimes the extent of the injury isn’t appreciated at first. “This happens a lot on the ski slopes,” Rossman said. “A skier tumbles and flips and their bindings don’t release. Their knee gets torqued, but once sitting still, they think that maybe they just ‘tweaked’ it. So they put their skis back on, and when they make their first cut, their knee buckles, and now they find themselves coming down the mountain on the rescue sled.”

ACL injuries have both short- and long-term consequences. Short-term, the player or athlete is sidelined for a substantial period, six months or longer, (and that’s often with surgery and rehabilitation), and long-term, should the athlete, continue to stress the wobbly joint through continued athletic activity, the risk of developing osteoarthritis increases later in life.

The Gender Difference

Why ACL injuries occur is more difficult to pinpoint than how they occur. ACL injuries can strike anyone, but there are certainly some individuals more prone to ACL injury. Some of the sports listed above can cause high forces on the ACL. Participants in these sports are especially susceptible to ACL injury. Another factor that contributes to ACL injuries is the gender of the patient. Multiple international research studies have shown female athletes are two to eight times more likely than their male counterparts to sustain an ACL injury. There are multiple theories as to why women are especially susceptible to ACL injury.

“About 15 years ago, physicians, physical therapists and athletic trainers noticed this tremendous discrepancy between genders and the frequency of ACL injuries,” Rossman noted. “A premier program, the Cincinnati Sports Medicine Center and their Director, Orthopedist Dr. Frank Noyes, MD, started tracking this trend. He hired a bio-mechanist to start researching what’s different about boys’ and girls’ knees. Why might females be more vulnerable?”

Noyes and his team, as well as other researchers around the country, scientifically ruled out a series of possible factors. Maybe all the good coaches coached only boys’ sports. Maybe girls just weren’t as athletic as boys. Maybe girls played on inferior fields and courts. Maybe their shoes were not as well designed as the boys. They dispelled and disproved all of these theories quickly.

“What they did find,” Rossman said, “is that girls’ hips and legs are aligned differently than the boys’. The girls typically have a wider pelvis, which mean their hips come from a wider angle to a knock- knee position. If you watch a lot of girls’ sports, you’ll note that when girls jump, their knees kind of bump together when they leave the ground and land. Or if you watch them run, there is often a kind of sashay motion, where their feet rotate in a circle during their stride instead of churning straight up and down with the hip, knee and ankle staying in a straight line.

“This isn’t every girl, of course,” Rossman added. “There are Mia Hamm’s out there that are more athletic and talented than 99.9% of all males, but in general when you look at girls, you see that they are more likely to have a flat foot and a knocked knee. And when their knee and thigh rolls inward, they are in what’s called the ‘danger position,’ and it is this position that puts the ACL at risk.”

In the danger position, just a slight bump or nudge can further put tension on the ligament. “They don’t have to be hit in the knee,” Rossman said. “Their knee is too often already in a bad alignment from cutting and landing from a jump.”

Hormonal Differences

Hormones also come into play. Boys simply have more muscle mass than girls. They’re stronger, especially in the hamstrings, which are critical for pulling the shin backward and protecting the ACL. Conversely, girls whose quadriceps muscles are stronger than their hamstrings risk an imbalance that tends to pull the shin forward and tear the ACL. Rossman notes that, “Weakness in the leg muscles also result in the athlete jumping and cutting with straighter hips and knees, as opposed to the more athletic ‘ready position’ and this too puts the ACL at risk.”

With an estimated 250,000 ACL ruptures every year in the United States, patients and their doctors have decisions to make regarding treatment options, regardless of how or why the injury occurred. On the one hand, victims can take relief that treatment options and surgical procedures have greatly improved over the last two decades, prompting this recent headline and article in USA Today, “Better repairs mean ACL tear is no longer a game-stopper.”

That’s true, but it doesn’t lessen the injury’s severity or seriousness. “Even though things are better now than they were years ago,” Rossman admitted, “and the best athletes can come back from it, you are not better off following an ACL tear.”

Next up: Treatment Options (Surgery reconstruction or conservative management?)

One Response to “Sports’ No. 1 Nemesis: ACL Injuries”


  1. ACL Injuries: The Road to Recovery — Part 3 in LaVerneOnline’s Exclusive 4-Part Series

Leave a Reply