Thursday, January 3, 2008

A New Epidemic: Women's Knee Injuries

More women atheletes are tearing their ACLs

By Jamie Callahan

Re-watching the game on film was the hardest. She knew what half, what minute, and what play her season ending-injury occurred, and she sat with fear and anticipation- preparing herself to relive it.
And then it came.
There was no one around her.
She just dropped.
“Ugh, I hated watching myself tear my ACL,” Kelsey Nickles, a 21 year-old student athlete at the University of Pennsylvania, recalled. “It just looked… so preventable, you know? There wasn’t even anyone around me. No one pushed me. No one twisted my knee the wrong way. It was just me.”
The disappointment of tearing her anterior cruciate ligament—also known as the ACL -- brought on the larger disappointment of not being able to play field hockey for at least a year. Her ACL would heal after surgery, but she would never be able to get back the time she missed on the field.
Nickles is just one of the number of women athletes that has to feel this disappointment – and recent research has discovered that female athletes are much more prone to this injury than men. The research says that5 are anywhere from 3 to 10 times more likely to tear their (ACLs) than men.
Elizabeth Arendt, MD, Associate Professor at the Department of Orthopaedic Surgery at the University of Minnesota, said in a medical forum that the rates of ACL tears for male and female athletes in similar sports in the NCAA are unequal.
She reported the findings of a research project in which the injuries of both male and female NCAA soccer players from the years 1989 to 2001were examined:
“The rates for ACL injuries in male soccer players went down significantly over time, while the rate in female athletes rose,” said Arendt.

Many reasons
So what are these reasons that make women more prone to tearing their ACLs?
Researchers admit that all of the reasons are not fully known. There are certain factors, however -- anatomic, hormonal and neuromuscular -- that have proven to play a role in the injury.
These factors are in addition to common reasons that men and women tear their ACL’s. In high impact sports, such as soccer, basketball, skiing, ice and field hockey, lacrosse, and volleyball, the ACL allows for common maneuvers that athletes use during competition: cutting, pivoting, and sudden turns.
Stable knee joints are critical to these actions. The anterior cruciate ligament, which runs up the center of the knee, is the primary ligament that allows the knee to bend in the correct direction: where the leg from the knee down bends backwards.
However, if the ACL becomes weak, it becomes harder to keep the knee bending in a backwards direction, and therefore easier for an athlete to dislocate his or her knee. When an ACL weakens, the leg from the knee down is more prone to sliding into an incorrect position forward, and the ligament tears.
Women, however, have to worry about more than just a weakened ACL when considering their chances of injury.
In the same forum, Bruce D. Beynnon, the director of research in orthopaedics at University of Vermont, said that there are physical differences between men and women that can cause women to be more prone to tearing their ACLs.
This theory, medically referred to as “the narrower femoral intercondylar notch theory” is based on the fact that women tend to be smaller in physique than men. They have smaller muscles and therefore, less strength. This lack of strength in their ACLs is seen as a possible cause for a higher increase of injury in females.
“It appears that the increased rate of noncontact ACLs seen in patients with narrower notches may simply be a manifestation of a smaller ACL,” Dr. Arendt confirms.
There are other factors that join with this intercondylar notch theory in assisting the injury among women.

Hormone levels
The menstrual cycle may also have additional effects on female athletes and their performances. In the forum, Dr. Beynnon described a study in which researchers found an increase in the prevalence of injuries during the menstrual phase. The studies showed that certain hormone regimens associated with menstruation weaken the ligament, leaving women more vulnerable during specific cycles.
Finally, in addition to the size of the ACL and the hormone levels, women show a difference in neuromuscular control of their knee joints.
“Three neuromuscular control imbalances are common in women athletes: ligament dominance, quadriceps dominance and leg dominance,” said Timothy E. Hewett, director at The Sports Medicine Biodynamics Center at Cincinnati Children's Hospital.
Ligament dominance, according to Dr. Hewett, refers to the way women’s bodies hit the ground and the effect it has on their ligaments.
“The lack of dynamic muscular control of the joint leads to increased valgus motion, increased force and high torque that can stress the passive restraints of the knee joint,” he said
In other words, when a woman lands, her knees cannot handle the pressure that occurs when she hits the ground.
In addition, a woman’s thigh muscles are stronger than the other muscles in her legs. This dominance can cause the knee to have a tendency to stay bent at a low angle during sporting events.
“ACL injury nearly always occurs when the knee is near full extension, where quadriceps dominance may put the ligament at increased risk,” Dr. Hewett said.
Lastly, leg dominance --in which there is an imbalance between muscular strength and coordination on opposite limbs -- is seen to be a cause. Not only is the weaker limb at increased risk of ACL injury, but the dominant one is as well.
“The weaker limb is compromised in its ability to manage even average forces [on the knee],” said Dr. Hewett, “… and the stronger limb may experience exceptionally high forces [on the knee] due to increased dependence on that side.”

Finding the cure
The increase in the amount of ACL injuries in female athletes have spurred researchers and doctors, such as Arendt, Beynnon, and Hewett, into finding answers to the problem
But the answers they found posed an even more important question: Can anything be done to prevent this injury?
Dr. Hewett said he was successful at discovering a form of prevention.
He led a study to evaluate the effect that a neuromuscular training program, which trained women more than once a week for a minimum of 6 weeks.
He found that women that trained in the program by participating in mobile stretching, balance, and strengthening exercises had a 72% lower incidence of ACL injury than untrained women.
In the study, he said, “trained women were not different than untrained men.” By incorporating mobile stretching -- or plyometrics -- balancing exercises and weight lifting, Dr. Hewitt found a program that placed women on an equal playing field with men, and the results indicated a decrease in injury risk in female athletes.
The existence of a training program that is proven to prevent injury leads to a question on why all female athletes aren’t asked to participate in such training?
“I had no idea [training programs] even existed prior to my conversation with a sports trainers after I already tore my ACL,” said Allison Ambrozy, a senior on the University of Pennsylvania women’s lacrosse team.
In her opinion, Penn’s athletic department is remiss in its duties of injury prevention.
“There are a lot of weaknesses with our athletic department… it’s frustrating, I don't expect that from them either. There are people on every level that could help change this, trainers, coaches, strength coaches, but no one seems to have enough incentive to change things, and that’s a shame,” said Ambrozy.

No training here
When asked about whether or not he was aware of any program that could limit the tendency for women to tear their ACLs, Mitch Biunno, head athletic trainer at the University of Pennsylvania responded, “I don’t know much about it.”
Biuno did, however, add that, “I’ve heard of ACL prevention programs that involve different types of stretching, but I don’t know to much about the research and if it is in fact legitimate and effective.”
Ten female athletes at Penn were informally asked if they were aware that they are 3 to 10 times more likely to tear their ACLs, and 9 out of the ten were unaware.
“The only reason I do know that is because I tore my ACL in high-school, no one at Penn told me,” Lauralynn Drury, captain of the Penn women’s squash team, replied to the question.
This could be due to the fact that the University athletic department is not educating athletes on this problem, but as Biunno has pointed out in his statement, the athletic department itself is not fully aware of the issues.
In addition to the relationship between prevention programs and university athletics, there could also possibly be a budding relationship between a different ACL program and athletic recruitment.
When asked whether or not, within the female athlete population, there is a way to find out if certain women are more prone to tearing them, Dr. Hewett responded, “yes.”
“Knee motion and knee loading during a landing task are predictors of anterior ligament injury risk in female athletes,” he said.
In a study he conducted in which there were 205 female athletes that played the high-risk sports of soccer, basketball, and volleyball, Hewett studied the way the athletes’ knees dealt with forces of landing.
He predicted that the prescreened athletes with previous ACL injuries would have less control over their knees when they landed, which would predict ACL injury risk.
At the end of the study, Hewett’s results showed that the methods he developed could be used to monitor neuromuscular control of the knee joint, or how the knee deals with impact, and possibly indicate the need for intervention.
“ [The methods] could help develop simpler measures of neuromuscular control that can be used to direct female athletes to targeted interventions,” he said.
So now, not only are the causes of ACL tears in women known, but there are also ways to decrease the risk of injury, as well as ways of assessing the risk.

Testing can tell
A new test that can assess the risk of a female athlete injuring her ACL by examining how she jumps and lands could cause a lot of problems with athletic recruitment.
What if colleges started asking recruits to have their risk of injury assessed before he or she could be considered for admission? The idea does sound logical from a recruitment standpoint, but is it fair?
“I honestly don't know how I feel about this test, in terms of its accuracy, my mental capacity to deal with knowing I'm at a higher risk, and how they would use it to judge incoming athletes,” said Ambrozy.
The risk-assessment program, or test, could potentially be threatening for high-school athletes and their futures in athletics, but it could also be helpful in indicating which athletes would benefit from the prevention programs.
Since collegiate athletes are more familiar with their bodies due to their experiences in strength training, conditioning, and playing, they have the ability to be more in tuned with their physical limitations. High-school athletes, however, are less experienced and lack strength and conditioning trainings. Collegiate level athletic departments may not have caught on to prevention and risk assessment programs because it is the high-school athletes that can more so benefit from them.
“I feel that many collegiate athletes have a strong intuition and understanding of their bodies. The program may be helpful for incoming freshman and I would like to see that program here at Penn,” said Nickles, who is now recovering from her second torn ACL surgery. She began to consider how things could be different:
“I mean, the fact that I could have known I was more inclined to injure myself, and then taken steps as a freshman to prepare my body… I would do anything to be able to get those years back and play hockey again.”
It’s impossible to regain that time, but if female athletes were more educated on the injury, it could prevent the disappointment and regret that many female athletes now deal with.

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