Women's Knee-Injury Mystery Unsolved

(WebMD)  It's still a mystery why women suffer more knee injuries than men do. And an elaborate new study fails to link ACL rupture to menstrual cycle.

The ACL, the anterior cruciate ligament, helps keep the knee stable. When overloaded, the ACL ruptures. This is extremely painful, as sport fans know from the familiar sight of athletes collapsing in agony. It also takes a long time to heal.

Female athletes suffer ACL rupture much more often than do male athletes. In soccer and basketball, women suffer ACL injuries three times more often than men do. While running obstacle courses during military training, female recruits suffer 11 times more ACL injuries than do male recruits, note the researchers.

Why? There's some evidence that ACL injuries are more common during certain phases of the menstrual cycle, although studies differ as to exactly which phase is to blame.

To settle the question, Ohio State University researcher Ajit M.W. Chaudhari, PhD, and colleagues used video tapes to analyze men and women as they performed various exercises that stressed their knees, their ACLs in particular.

The study enrolled 12 men and 25 women. Thirteen of the women were taking oral contraceptives. Each woman underwent testing at different phases of her menstrual cycle.

The result: Regardless of their menstrual phase or contraceptive use, women put no more strain on their ACLs or related muscles than did men.

"Hormone cycling in women does not appear to affect either knee joint or hip joint loading," Chaudhari and colleagues report. "Women do not appear to have significantly different loads than men during any phase of the menstrual cycle. Moreover, the use of an oral contraceptive does not appear to affect joint loading."

If there is an effect of sex hormones on knee injury, the researchers suggest, it must be part of a complex interaction between hormones, ligament structure, fatigue, and "neuromuscular control."

The study appears in the May issue of The American Journal of Sports Medicine.

By Daniel DeNoon
Reviewed by Louise Chang
©2007 WebMD, Inc. All rights reserved

[fatherteresa]

I know why my knees hurt and it has nothing to do with the above report. My neighbours are using some sort of instruments to zap people and animals. All you people out there that have unexplainable pains - you are being zapped by your unfriendly neighbours.

[fatherteresa]

I know why my knees hurt and it has nothing to do with the above report. My neighbours are using some sort of instruments to zap people and animals. All you people out there that have unexplainable pains - you are being zapped by your unfriendly neighbours.

[goddesspryzm]

why do women screw up their knees more.. let me see.. we carry a child up to an add'l 50 lbs. our bodies produce a chemical called relaxin that on purpose makes our joints, body parts soft in order to let a baby come out naturally. that hormone is released the last month of pregnancy..who's to say that hormone doesn't make not only the hips but other joints looser and easier to mess up. then we crawl around on knees with baby, scrub floors, vacuum, dust, crawl around on knees to find things under furniture. Women with children by far do more physical activity in one day than 3 men do in a gym in one. We screw up our knees because we use them more, in different ways than some stupid money wasting study will ever figure out.

[phantmqueen]

I have an extensive background in statistics, this study is seriously underpowered. Power is the ability to see differences between groups when there is a difference to be seen. It is largely based on sample size: 12 men and 25 women, almost half of which were on birth control, is not nearly enough people to see a real difference among groups.

[jimbo505]

I think the comments system works great!

[cnjcc]

GrammaWhamma:

Their IT people are asleep. What is causing it is, when you click on Publish and your comment doesn't appear immediately, and you get a message that the publish button has been temporarily disabled ... this makes you think that your comment didn't get published, so when the publish button comes back to life you hit it again. What's happening is that the original comment is just being delayed, but gets posted sometime later. I emailed the Web site people about it, but never got a reply.

[grammawhamma]

Looked like first post didn't work. Sorry...hate double posting but I see it's been happening alot lately on this site. CBS you need to fix this problem.

[grammawhamma]

It's from women kneeing men in the groin!! No seriously...sigh, yet another useless expensive study.

[grammawhamma]

Sigh.....yet another useless expensive study. Maybe it's caused by women kneeing men in the groin?? Sorry...I'm over tired and just had to say it. Maybe its because women carry kids around during pregnancy and afterwards, scrub floors, cook, clean and wait on their husbands. All this after coming home from a full time job to help make ends meet.