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Preventing Anterior Cruciate Ligament Injuries

Some people in the medical field say there are no such things as "accidents." There are always reasons why people get sick or are injured. And this idea may be very true when it comes to ruptures of the anterior cruciate ligament (ACL) of the knee.

Sure it's easy to say the ligament ruptured when the athlete was tackled and another player landed on that leg. Or when the basketball player's foot was planted on the floor and she got knocked over while trying to pivot and shoot.

But the truth is these events happen many, many times to other athletes who don't end up with an injury. So the question becomes what risk factors contribute to injuries like a ruptured ACL? And is it possible to modify those risks to avoid or prevent such disabling trauma?

In this article, athletic trainers from the University of Vermont do a literature review looking for neuromuscular and anatomic risk factors. They labeled the research as Part 1 indicating that they will continue this research and report on other types of risk factors later.

In this first part, knee geometry, alignment, and joint laxity are half the focus. Knee geometry refers to three specific measures of shape, depth, and angle that have been linked with ACL injuries. These include decreased intercondylar femoral notch size, decreased depth of concavity of the medial tibial plateau, and increased slope of the tibial plateaus.

The second area of interest (neuromuscular risk factors) included posture, landing biomechanics, ground reaction forces, core stability, trunk displacement, and active proprioceptive repositioning error. Changes in movement patterns from any one of these factors increase the strain on the ACL and seem to be contributing to the increased risk of ACL injuries.

These anatomical and biomechanical terms may not mean much to you, but surgeons examine the anatomic features for ways to reconstruct and realign the knee after injury. And Physical Therapists and athletic trainers study ways to work with athletes who may have one or more of the neuromuscular variations that could increase the risk of ACL injury. The authors do provide an in-depth discussion of each anatomic and neuromuscular risk factor mentioned here.

The benefit of research of this type is in being able to counsel athletes wisely and develop effective prevention strategies. Injuries like ACL ruptures can end an athlete's career -- or at least sideline the player for a season or more. There is a future risk of knee osteoarthritis that must be considered as well.

With proper training and good body mechanics, even athletes with nonmodifiable anatomic risk factors may be protected from such injuries. Knee geometry cannot be changed but balanced muscle strength, motor control, and neuromuscular coordination could make a difference.

Exercise programs aimed at these areas during different stages of growth and development may help. Further research is needed to fully understand all ACL risk factors and find appropriate prevention strategies. The role of skeletal and muscular maturation versus conditioning must be evaluated as well.

Reference: Helen C. Smith, MS, ATC, et al. Risk Factors for Anterior Cruciate Ligament Injury: A Review of the Literature - Part 1: Neuromuscular and Anatomic Risk. In Sports Health. January/February 2012. Vol. 4. No. 1. Pp. 69-78.