ACL Injury Prevention: What Does Research Tell Us?
How big is the problem?
There are an estimated 350,000 ACL surgeries annually in the USA
Approximately 79% of those individuals develop knee osteoarthritis
One in four youths who suffer an ACL injury will suffer a second ACL injury in their athletic career
Competitive and recreational athletes between the ages of 15 and 25 are at the greatest risk of injury.
Athletes who suffer a knee injury prior to participation in D1 career have an eightfold increased risk of suffering another knee injury during their D1 career and spend 50% more time on the disabled list.
Who is most susceptible?
Female athletes are at risk four to six times greater than their male counterparts.
Female high school athletes had a ninefold increase injury risk and fivefold in collegiate sports and those that competed at a higher level of play had a five times higher risk than their male counterpart.
Why do ACL injuries occur and in which sports?
Injury to the ACL occurs during dynamic activities that primarily involve cutting and pivoting and can occur during landing after a jump.
Sports that require high dynamic loading of the knee and report a high incidence of injury include soccer, volleyball, handball, and basketball.
Six Principles of a Prevention Program
Age: It is recommended that ACL prevention programs be implemented at an early age (before age 14). Fewer ACL injuries were documented in younger athletes who performed a neuromuscular training program compared to older athletes who performed the same program.
Biomechanics: Faulty biomechanics (body position, especially upon landing from a jump) correlated with increased strain on the ACL. Bucking in of the knee is one of the strongest indicators of increased ACL injury risk.
Compliance: Compliance of performance of an ACL prevention program is vital to the ability of the program to be successful at reducing injury rates. Compliance greater than 66% resulted in an ACL injury reduction rate of 82%. However, when compliance rate dropped to less than 66%, ACL injury reduction rate dropped to 44%.
Dosage: Frequent participation in an ACL prevention program decreases risk for ACL injury. Most studies agree that each session should be between 20 and 30 min and should be performed several times per week. Optimally, they should be initiated in the pre-season and continued throughout the season to attain the full effectiveness of the program.
Feedback: Many studies included some type of feedback, and whether verbal or visual, a decrease in ACL injuries has been shown. Feedback can be in the form of verbal cueing from a coach or a training partner, but can also be visual as in a training video.
Exercise: Exercises focus on three different components: plyometrics (jumping and landing), neuromuscular training (agility and balance), and strength training. Goals are increased core strength (truck stability) and increased endurance.
