ACL injuries in young athletes who are still growing has become a rising clinical problem in recent years. While it is widely known that teenage athletes have a high rate of re-tearing their ACL, researchers from Hospital for Special Surgery (HSS) set out to determine if there is a specific age group more at risk within this population.

Over 300 HSS patients were assessed in three groups based on the amount of skeletal growth remaining:

• Group 1 patients were mainly comprised of elementary and middle school athletes up to 7th grade (3-6 years left of growth).
• Group 2 patients were predominantly 8th and 9th graders (2-3 years left of growth).
• Group 3 patients included high school and young collegiate athletes (fully grown).

This prospective study evaluated two year clinical outcomes from these adolescent patients who underwent primary ACL reconstruction. It found that the rate of revision ACL reconstruction was higher and the return to sport rate was lower in Group 2.

The successful Group 1 cohort saw a 6 percent rate of revision and a perfect 100 percent return to sport. The Group 3 numbers were similar (6 percent revision rate, 94 percent return to sport) while the Group 2 segment saw a much higher 20 percent revision rate and only a 86 percent return to sport rate.

"There could be multiple factors associated with the less successful outcomes we observed in the Group 2 athletes," said Frank Cordasco, MD, MS, sports medicine surgeon at HSS and senior study author. "This Group 2 cohort bridges the divide between middle school and high school. At this age, when you miss a season and re-join your teammates in a competitive high school athletic environment, you have not developed the same sports-specific skills that this non-injured group did during the gap year, which can lead to another injury."

The ACL reconstructions in Groups 1 and 2 used the same hamstring graft, while Groups 2 and 3 utilized the same surgical technique. One size does not fit all for ACL injuries, and different techniques and materials are used based on age and type of tear. There has not been one widely-agreed upon method for patients who aren’t yet fully grown.

"We are continually evaluating our techniques to improve our outcomes and lower this revision rate for Group 2 patients. They are too young to use the traditional patella tendon graft that we prefer with athletic young adults," said Dr. Cordasco. "We are assessing modifications in our technique which include the addition of a lateral ligament augmentation performed at the time of the ACL reconstruction, changing the graft choice from hamstring to quadriceps tendon which we believe may be a better choice for this high risk cohort of young athletes, and utilizing implant mediated guided growth when indicated."

Group 1 patients underwent an all-epiphyseal hamstring autograft ACL reconstruction, which was developed by Dr. Cordasco and Daniel Green, MD, MS, FAAP, FACS. This technique uses sockets instead of tunnels and provides improved graft incorporation and tendon-to-bone healing as a safer alternative for young patients.

"This study shows that our all-epiphyseal technique is successful in treating young athletes who are not yet skeletally mature," said Dr. Green, pediatric orthopedic surgeon at HSS and senior study author. "These patients used to be denied surgery because of their age, but we have developed an effective reconstruction technique to get them back in the game."

This study also illustrates the need for stronger communication to parents, coaches, PTs and athletic trainers about the risk of ACL injuries in this age group.

"If an 8th or 9th grader walks into a doctor’s office with a torn ACL, the high risk needs to be communicated to the family," said Dr. Green. "Conversely, if it’s a younger middle school athlete, the success rate is pretty good."

The recovery period is just as important when looking at preventing re-tears and returning to sport.

"To achieve optimal results after surgery, we counsel our patients to complete an ACL prevention injury program," added Dr. Green. "It’s very important that these athletes only return to sports after they have regained great physical shape and learned prevention techniques."

HSS established the HSS Sports Safety Program in 2015 which launched the first ACL program customizable by skill level and sport type in 2016.

This study was presented today at this year’s annual meeting for the American Academy of Orthopaedic Surgeons (AAOS).