Common knee ligament injury can be game-changer
The knee is a marvel of mechanical engineering -- the most complex joint in the human body. But to an athlete, it's also extremely vulnerable to being damaged.
One type of injury involves the anterior cruciate ligament (ACL), and it can significantly alter the path of an athletic career.
"It's a fairly common injury," said Dr. Jason Reiss of Advanced Orthopedic Center. "We see it quite often with any running-and-cutting-type sport."
ACL injuries involve the strain -- or, more often, the tearing -- of the ligament.
"There are indirect and a direct causes to an ACL injury," Reiss explained. "A direct cause is usually a blow to the knee, causing it to bend in an abnormal manner. An indirect cause would be a sudden stop where the ligament gives way to the momentum of the body."
"It's pretty much situational with contact sports that sometimes the foot is planted," added Dr. David Kaler of Charlotte Orthopaedic Clinic. "If your body rotates around that planted extremity, something's got to give."
That something is usually the ACL.
'Pop' goes the knee joint
"Women are very prone to ACL injuries just because of anatomic variances between men and women that make women more susceptible," Reiss said.
Statistics indicate this is true. According to a 2009 National High School Sports-Related Injury Surveillance Study, the top three sports for ACL injury are, in descending order, girls' soccer, boys' football and girls' basketball.
Depending on the severity of the injury, some athletes will continue to play. But that's almost always due to the ligament being strained or slightly torn.
"You can have a little strain of the ligament to a partial tear to a full tear," Reiss said, "and that's where diagnosis can get a little more complicated because it may not be quite as pronounced as an acute rupture."
"Usually when you really tear or injure your cruciate, you know you did something bad because most people will tell you they heard a pop," Kaler said. "Usually with a complete tear, there's no question you've done something rather significant to your knee."
The pop is usually followed by pain so intense, the athlete is unable to walk. Any pressure put on the joint creates a feeling that it's "giving way." Also, the knee begins to swell almost immediately from bleeding caused by the tear.
For any kind of pain or instability, however, Reiss recommends the athlete receive medical attention.
"There are other issues in the knee could be a problem," he said. "There could be an injury to the bone or any of the other ligaments around the knee as well. If you do have an injury that requires you to stop playing, certainly an evaluation by a physician would be recommended at that point."
For some athletes, an ACL injury could be life-changing.
According to Kaler, most athletes who suffer an ACL injury require surgical reconstruction. This involves taking tissue -- either from another area of the athlete's body or donated from a cadaver -- in order to reconstruct the ligament. But it's not a quick fix.
"It takes about a year for your body to remodel that ligament to something that's 'you,'" he said, "so you're somewhat limited in your activity level for that year. If you play, you should play in an ACL brace."
There's another downside to reconstruction as well.
"I think that most people that have had an anterior cruciate reconstruction tell you that it's probably not quite the same as their unaffected knee," Kaler said.
What reconstruction does is attempt to reproduce part of the action of the ACL, he explained.
The cruciate ligaments are so named because they cross, like an X. As the knee goes from being straight to bending, the fibers rotate.
"Using tissue from other places, it's hard to reproduce that particular mechanism," Kaler said. "People have tried different techniques to try to reproduce it, but you still have a sense of a little bit of instability."
He noted that professional-level athletes who tear an ACL will likely never get back to the "100 percent" at which the knee was able to function prior to the injury.
While many times an ACL injury is just a case of an arbitrary blow to the leg, Reiss argues that, in some cases, there are precautions athletes can take.
Prevention and protection
"Prevention is very important," he said. "In most cases, quadriceps strength is the key to prevention of an ACL injury. Quadriceps can help protect the knee."
Reiss recommends a "good stretching and strengthening program that focuses on balancing the knee between the quadriceps and the hamstrings."
These include squatting movements and leg raises.
What an athlete doesn't want to do is ignore even a minor ACL injury.
"If you tear your anterior cruciate and for some reason you don't get treatment -- and your knee is reasonably functional for you -- you have a 25 percent chance of developing arthritic changes at an earlier age," Kaler said.
He compared it to having a car whose front end is out of alignment.
"You can still drive it but your tires wear at an increased rate," he said. "So if you don't have this ligament, you can still function -- a lot of people function reasonably well without one. But there's that little bit of instability that increases the wear rate on the knee, so they wind up with a knee replacement or at least some type of knee surgery at an earlier age than what you would anticipate just from the aging process."