ACL Injury Research Raises More Questions Than Answers

"The hurry-er I go, the behind-er I get" is a line from the old comic strip Pogo. The academic corollary to that is "the more I learn, the more confused I get."

Just when I think I have a pretty good handle on the ACL injury thing, something else comes up that muddies the water and makes it all so confusing.

Used to be that an ACL injury was potentially a career-ending injury. If you were a junior in high school and tore an ACL, the year rehab meant your high school career was over.

Then it turns out that a year's rehab isn’t needed. The rehab program now can start right away and progress so quickly that a player like Rod Woodson of the Pittsburgh Steelers can tear an ACL in the preseason and be ready for the playoffs.

OK, so the rehab can move things along real fast. Now we see that women are tearing their ACL at a faster clip than men. So the push is on prevention of ACL injuries in women.

But how do you prevent something when you don’t even know how it happens? So, you collect hundreds of videotapes of knee injuries in sport and try to see what is common about the injuries. You conduct detailed interviews of patients trying to find out how the injury occurred.

I mean, there were 11 ACL injuries in eight players in the player pool for the women’s U19 world championship team.

From tapes and interviews, it turns out that cutting, stopping, and landing from jumps are risky activities for both men and women. A long horizontal component adds to the risk. Usually the knee is near extension and hips are pretty straight, more so in women.

Easy enough, just teach women to lower their center of gravity. But how? There is a group out of Cincinnati that will tell you ... for $125 per athlete. A study in California is looking at the girls in a youth league.

Teams volunteered to participate, and those teams had a dramatic reduction in ACL injuries. But those coaches volunteered their teams. Maybe they were just more tuned into the problem, and by being attentive to the potential problem, treat their players differently. Is the reduction in injury tied to the specific exercises or the combination of ANY exercise by a concerned coach?

A Swedish project, unpublished as yet, taught female soccer players a series of exercises that should protect them from ACL injury. Those players did have a reduction in injuries. So that program works, right? More details show that only 25% of the players actually did the program. So it’s not the program, but the education that went with the activities?

What about that balance training program in Italy that showed a reduction in ACL injuries? Were you aware that some Swedes duplicated the project and found that the players who were in the balance training group actually had a higher rate of injury than the control group?

Now comes some information that maybe the ACLs that tear are just small ACLs. If the ACL is below some threshold, that player is at a greater risk of injury regardless of gender. Eighty percent of women have an ACL below that threshold, but so do 20% of men, and those people, male or female, are the ones who tear their ACL.

So, if that is the case, what can you really do to prevent those injuries? You can’t make your ACL bigger. (Well, you can. If you tear a small ACL, the new graft is bigger than the native ACL. Tear both; now the stability of the knees is really strong — so go play and don’t worry about it?).

If the ligament size is an issue, then do we focus our prevention efforts only on those with a small ligament? If so, then we need a way to figure out the size of the ligament — but an MRI is very expensive and no one has a way to estimate ligament size without expensive imaging.

Does that mean forget about estimating the ligament size, and just teach everyone to control these risky activities? But what activities? That brings us back around to learning how to refine movements the players already do … and that brings us to the compliance question.

If you are as confused as I am, then when someone knocks on your door promising a program to prevent ACL injuries, I would probably be skeptical. If a program is sold as such, then shouldn’t some players actually be tearing their ACL during the program?

I mean, the exercises are supposed to prevent the injury by teaching one how to do these risky activities, and sometimes someone is going to goof and tear their ligament.

As a coach, what do you do? First off, I would accept the fact that ACL injuries are a problem. I would make sure my players (middle, high school and college age) know which movements are problems. Some of the best studies suggest that doing these movements in an erect stance magnifies the risk, so stress doing things lower.

The old "ready position" needs to be reintroduced, or in a more soccer-related description, what the Dutch refer to as "suppleness." Will a dent be made? There is hope …

Copyright © 2002 Don Kirkendall