The incidence of a serious knee injury can be reduced dramatically if high school and college athletes are taught how best to bend, land, jump and pivot their knees, according to a study presented at the annual meeting of the American Academy of Orthopaedic Surgeons.
Researchers headed by Eric Swart, an orthopedic resident at Columbia University Medical Center in New York City, examined strategies for reducing tears of the anterior cruciate ligament, which stabilizes the knee joint.
ACL tears are one of the most common sports injuries, especially among young female athletes. Repairing a torn ACL often requires surgery and a long period of rehabilitation.
According to a mathematical model for risk and screening constructed from published data on student athletes aged 14 to 22, universal neuromuscular training can reduce the incidence of ACL tears by 63 percent (from 3 percent to 1.1 percent per season), the researchers said.
If neuromuscular training were restricted to high-risk athletes only, the incidence of ACL injuries could be reduced by 40 percent (from 3 percent to 1.8 percent), the researchers found.
Implementing a neuromuscular training program could reduce injury-related costs by about $275 per player per season, Dr. Swart and his researchers calculated.
They weren’t surprised to learn the training program would be more cost effective than no intervention at all, but “we were impressed with the magnitude of the benefit,” Dr. Swart said.
Because universal training reduces the incidence of ACL tears by more than half again as much as one limited to high-risk athletes, the universal program is also more cost-effective than the targeted program, the researchers found.
Sam Akhavan, director of the Human Motion Training Academy at Allegheny General Hospital, was skeptical of that finding. If every athlete received neuromuscular training, “the drain on the system would be a little bit too high,” he said.
Finding those at risk
AGH Sports Medicine has developed a simple test to identify athletes at greater risk, and to zero in on their problems, said Dr. Akhavan, a team physician for the Pirates and the Riverhounds. Certified athletic trainers from the sports medicine program supervise the test.
“It takes just 10 seconds,” he said. “You have them jump up and down 10 times. We can easily tell if they’re not landing appropriately, if their core is weak, which helps us target what the problem is.”
Once those at high risk and their particular problems have been identified, “we can tailor our program somewhat to fit the needs of the individual athlete,” Dr. Akhavan said.
An at-risk group that requires particular attention are athletes who have torn an ACL before, he said. They are four to five times more likely to tear their other ACL than is an athlete who has never suffered this injury.
In the spring of 2010, the Human Motion Training Academy conducted a study with players from the girls’ basketball teams at Avonworth and Northgate high schools to determine which specific exercises are most effective in reducing ACL tears.
In the initial jump test, 15 of 20 students received “at risk” scores. After 12 training sessions, all the athletes who took part were no longer judged to be at risk.
In addition, all the athletes who participated showed significant improvement in how high they could jump, in agility and explosiveness, Dr. Akhavan said.
A number of different exercises can be incorporated in a neuromuscular training program. All include warmups, exercises to strengthen the knee, jump training (plyometrics), and stretching.
Proper warmups and stretching prepare muscles and joints for exercise, which reduces the risk of injury. Strengthening the muscles around the knee joint make it more resilient and less prone to damage. Landing improperly from a jump is one of the most frequent causes of ACL injuries, especially among girls, who are about nine times more likely than boys to tear an ACL.
One of the more popular neuromuscular training programs is the PEP (Prevention Injury and Enhance Performance) program, developed at the Santa Monica Orthopaedics and Sports Medicine Research Foundation. It takes 15-20 minutes to complete, and should be done three times a week during the season, its creators say.
A universal neuromuscular training program like PEP would cost about $1.25 a day per athlete to implement, Dr. Swart’s research team estimated.
Surgeries to repair torn ACLs cost, typically, between $5,000 and $17,000.
Dr. Akhavan and his team looked at PEP and at neuromuscular training programs developed in Cincinnati and in North Carolina before designing their own, said Craig Castor, AGH Sports Medicine supervisor.
“PEP is designed as a warmup,” he said. “Ours is more of a supplement” to training programs for particular sports.
The AGH program currently consists of two 45-minute sessions a week for eight weeks, Mr. Castor said.
“We focus on forward jumping in one session, on lateral movement the next,” he said.
“We’ve made the program a little more intense,” Mr. Castor said. Athletes are more likely to jump or land improperly — and hurt themselves — when they’re tired, “so we like to test them when they’re worn out.”
AGH has trained 50 to 75 local high school athletes a year since the program began. The cost is $35 per athlete per session, or $1,000 for a team of up to 15 athletes for the entire eight-week program, Mr. Castor said.
Jack Kelly: firstname.lastname@example.org or 412-263-1476.