[M T]

The Utah Women's basketball team's website's article update before their C.al game, dated Saturday, does not state it is an ACL injury

Taryn Wicijowski left the Stanford game midway through the first half with a knee injury. She will be reevaluated before Sunday's game.

I continue to hope that the injury was minor and she can surprise their next opponent.  I will note that I saw no ice on the knee during the second half and I saw her stand and (stiffly) move around on the knee with no crutches.  I would be very surprised if they thought she had an ACL injury but didn't put her on crutches or ice the knee, which appear to be part of the recommended first aid until it is evaluated.  But I am no physician!

I remember watching one Stanford player tear her ACL as she was headed into the step to elevate to the basket.  I don't remember an awkward landing where her knee obviously was inside her ankle (but that could be just my memory).  But it made me wonder whether the article here was the best theory out there.  Here are different perspectives on the injury:

A theory of compressive forces triggering the injury (and, as I read it, causes an internal rotation ("crumple"), perhaps exacerbated by the knee not being above the foot):
http://www.smartplanet.com/blog/big-stor...knees/101  (25 Sep 2012)

Around the time that Sheehan-Gavelli was working on her thesis at Stanford, using the cardiac MRI to image moving bones, Dr. Barry Boden, now an orthopedic surgeon outside Washington, D.C., was at Duke University, starting to look at how ACL injures occur. “Seventy percent of these are non-contact injuries,” he said, “so I thought if we had a better understanding of how they happened, we could prevent some of these injuries.”

Several years ago, he began looking at videotapes of NBA and WNBA games during which athletes were tearing their ACLs and comparing them to videos of similar movements that weren’t causing injuries. When he slowed the tapes, Boden was able to classify dangerous and safe landing positions. He could see that the injured athletes landed on their heel or flat-footed, and all the non-injured athletes landed on the ball of their foot.

The faulty position was causing a compression injury. It’s like jamming your finger into a basketball. Or, to use a different metaphor, it’s like the crumple zone of a car, which absorbs the impact of a collision so the driver doesn’t have to. Similarly, the human calf muscles are designed to absorb the force of a jump when, say, you dunk a basketball and land on your toes. If you land flat-footed, the impact goes directly to your knees. The theory was that landing flat-footed causes the knee to jam and the femur snaps the ACL.

Boden teamed up with Sheehan-Gavelli to further study these injuries; he provided the gruesome videos of the injuries, and she offered an understanding of the knee mechanics, took measurements and provided statistics. They looked at patients in a standing MRI machine — in both the safe and dangerous positions — which offered insight into how the leg is aligned and how gravity affects someone in a fall. Combining that data with the videos, the duo was able to determine how the injury occurs.
...
“We know from a biomechanical standpoint that we can train these athletes to keep their legs from internally rotating when they jump and land,” Mandelbaum said, taking a break from watching soccer at the Olympic Games last month. “There is a learning to it — not only for the knee and hip but for the brain –neuroplasticity. It’s like playing the piano. After six weeks, we can change the biomechanical variables and change the brain waves.”
...
“The concept is simple,” Beutler said. “Teaching people to land softly, toe to heel, not heel to toe. Use your body as God intended you to use it — keep your knees over your toes and use your knees as hinges. We like things to bend straight, not like corkscrews.”

Sheehan-Gavelli said for all the research findings, there are still various camps when it comes to the cause of ACL tears, and there are still people who question the effectiveness of prevention exercises. Dr. Kevin Shea, an orthopedic surgeon in Boise, Idaho, has conducted a study looking at female high school athletes and found that retraining them doesn’t reduce the risk of injury; he said if it’s possible, the retraining may take years, not weeks.

(Sep 2009) Seemingly different theory, based on similar evidence, suggesting more pressure on the knee from dynamics of the body at the time of impact.
http://well.blogs.nytimes.com/2009/09/09...-in-girls/

They solicited videos from surgeons and coaches showing the exact moment when athletes, male and female, suffered an ACL tear. They also gathered videos of female basketball players performing similar movements — foot plants, pivots, and so on — without tearing their ACLs. Using computer software, they marked and triangulated exactly how the athletes were positioned. What they found, according to the results made available online in April in the British Journal of Sports Medicine, was that young women whose ACLs had popped exhibited more trunk sway than the men or the uninjured women; when they landed, or planted a knee to switch directions, their upper bodies wobbled to one side. This placed great pressure on their planted knee, collapsing it inward and overloading the ACL. “Our research suggests that the issue in injured female athletes,” Hewett says, “is a lack of high-level ability to control deceleration and acceleration at the center of their mass in three-dimensional space.”

In that same article, another experiment is mentioned.

In the meantime, McLean, at the University of Michigan wonders whether all of the current theories about ACL injuries in girls are reductionist. For a study made available online in May in the journal The Knee, he attached ACL-damaged knees from male and female cadavers to a machine that applied loads similar to those experienced during various athletic movements and found that, “really, no two knees respond alike,” he says. Some ACLs from male cadavers readily tore; some from women held fast under every tension.

However, the article linked to was a Dec. 2009 article (with McLean as an author) and appears to be different than that description.  Based on cadaver experiments, the team created models of the ACL strain (I presume they mean stretching) through a range of forces on knees of both sexes.  Per those models, the female ACL experiences significantly greater strain than male for almost all situations.  The stated suggestion is that the female ACL will be injured by a smaller force on the knee than the male ACL.  I believe the reason for the disparity is solely in the structure of the knee itself.
http://www.sciencedirect.com/science/art...6009000751

While gender-based differences in knee joint anatomies/laxities are well documented, the potential for them to precipitate gender-dimorphic ACL loading and resultant injury risk has not been considered. To this end, we generated gender-specific models of ACL strain as a function of any six degrees of freedom (6DOF) knee joint load state via a combined cadaveric and analytical approach. ...
Predicted female ACL strains were also significantly larger than respective male values for both simulated 6 DOF load scenarios. Outcomes suggest that the female ACL will rupture in response to comparatively smaller external load applications. Future work must address the underlying anatomical/laxity contributions to knee joint mechanical and resultant ACL loading, ultimately affording prevention strategies that may cater to individual joint vulnerabilities.

[M T]

The Utah Women's basketball team's website's article update before their C.al game, dated Saturday, does not state it is an ACL injury

Taryn Wicijowski left the Stanford game midway through the first half with a knee injury. She will be reevaluated before Sunday's game.

I continue to hope that the injury was minor and she can surprise their next opponent.  I will note that I saw no ice on the knee during the second half and I saw her stand and (stiffly) move around on the knee with no crutches.  I would be very surprised if they thought she had an ACL injury but didn't put her on crutches or ice the knee, which appear to be part of the recommended first aid until it is evaluated.  But I am no physician!

I remember watching one Stanford player tear her ACL as she was headed into the step to elevate to the basket.  I don't remember an awkward landing where her knee obviously was inside her ankle (but that could be just my memory).  But it made me wonder whether the article here was the best theory out there.  Here are different perspectives on the injury:

A theory of compressive forces triggering the injury (and, as I read it, causes an internal rotation ("crumple"), perhaps exacerbated by the knee not being above the foot):
http://www.smartplanet.com/blog/big-stor...knees/101  (25 Sep 2012)

Around the time that Sheehan-Gavelli was working on her thesis at Stanford, using the cardiac MRI to image moving bones, Dr. Barry Boden, now an orthopedic surgeon outside Washington, D.C., was at Duke University, starting to look at how ACL injures occur. “Seventy percent of these are non-contact injuries,” he said, “so I thought if we had a better understanding of how they happened, we could prevent some of these injuries.”

Several years ago, he began looking at videotapes of NBA and WNBA games during which athletes were tearing their ACLs and comparing them to videos of similar movements that weren’t causing injuries. When he slowed the tapes, Boden was able to classify dangerous and safe landing positions. He could see that the injured athletes landed on their heel or flat-footed, and all the non-injured athletes landed on the ball of their foot.

The faulty position was causing a compression injury. It’s like jamming your finger into a basketball. Or, to use a different metaphor, it’s like the crumple zone of a car, which absorbs the impact of a collision so the driver doesn’t have to. Similarly, the human calf muscles are designed to absorb the force of a jump when, say, you dunk a basketball and land on your toes. If you land flat-footed, the impact goes directly to your knees. The theory was that landing flat-footed causes the knee to jam and the femur snaps the ACL.

Boden teamed up with Sheehan-Gavelli to further study these injuries; he provided the gruesome videos of the injuries, and she offered an understanding of the knee mechanics, took measurements and provided statistics. They looked at patients in a standing MRI machine — in both the safe and dangerous positions — which offered insight into how the leg is aligned and how gravity affects someone in a fall. Combining that data with the videos, the duo was able to determine how the injury occurs.
...
“We know from a biomechanical standpoint that we can train these athletes to keep their legs from internally rotating when they jump and land,” Mandelbaum said, taking a break from watching soccer at the Olympic Games last month. “There is a learning to it — not only for the knee and hip but for the brain –neuroplasticity. It’s like playing the piano. After six weeks, we can change the biomechanical variables and change the brain waves.”
...
“The concept is simple,” Beutler said. “Teaching people to land softly, toe to heel, not heel to toe. Use your body as God intended you to use it — keep your knees over your toes and use your knees as hinges. We like things to bend straight, not like corkscrews.”

Sheehan-Gavelli said for all the research findings, there are still various camps when it comes to the cause of ACL tears, and there are still people who question the effectiveness of prevention exercises. Dr. Kevin Shea, an orthopedic surgeon in Boise, Idaho, has conducted a study looking at female high school athletes and found that retraining them doesn’t reduce the risk of injury; he said if it’s possible, the retraining may take years, not weeks.

(Sep 2009) Seemingly different theory, based on similar evidence, suggesting more pressure on the knee from dynamics of the body at the time of impact.
http://well.blogs.nytimes.com/2009/09/09...-in-girls/

They solicited videos from surgeons and coaches showing the exact moment when athletes, male and female, suffered an ACL tear. They also gathered videos of female basketball players performing similar movements — foot plants, pivots, and so on — without tearing their ACLs. Using computer software, they marked and triangulated exactly how the athletes were positioned. What they found, according to the results made available online in April in the British Journal of Sports Medicine, was that young women whose ACLs had popped exhibited more trunk sway than the men or the uninjured women; when they landed, or planted a knee to switch directions, their upper bodies wobbled to one side. This placed great pressure on their planted knee, collapsing it inward and overloading the ACL. “Our research suggests that the issue in injured female athletes,” Hewett says, “is a lack of high-level ability to control deceleration and acceleration at the center of their mass in three-dimensional space.”

In that same article, another experiment is mentioned.

In the meantime, McLean, at the University of Michigan wonders whether all of the current theories about ACL injuries in girls are reductionist. For a study made available online in May in the journal The Knee, he attached ACL-damaged knees from male and female cadavers to a machine that applied loads similar to those experienced during various athletic movements and found that, “really, no two knees respond alike,” he says. Some ACLs from male cadavers readily tore; some from women held fast under every tension.

However, the article linked to was a Dec. 2009 article (with McLean as an author) and appears to be different than that description.  Based on cadaver experiments, the team created models of the ACL strain (I presume they mean stretching) through a range of forces on knees of both sexes.  Per those models, the female ACL experiences significantly greater strain than male for almost all situations.  The stated suggestion is that the female ACL will be injured by a smaller force on the knee than the male ACL.  I believe the reason for the disparity is solely in the structure of the knee itself.
http://www.sciencedirect.com/science/art...6009000751

While gender-based differences in knee joint anatomies/laxities are well documented, the potential for them to precipitate gender-dimorphic ACL loading and resultant injury risk has not been considered. To this end, we generated gender-specific models of ACL strain as a function of any six degrees of freedom (6DOF) knee joint load state via a combined cadaveric and analytical approach. ...
Predicted female ACL strains were also significantly larger than respective male values for both simulated 6 DOF load scenarios. Outcomes suggest that the female ACL will rupture in response to comparatively smaller external load applications. Future work must address the underlying anatomical/laxity contributions to knee joint mechanical and resultant ACL loading, ultimately affording prevention strategies that may cater to individual joint vulnerabilities.