Eyewitness News reporter Sandra Bookman shows us what that means for injured children.
Walking around is getting easier for 14-year-old Steven Polanco. A few months ago, he tore his anterior cruciate ligament, or ACL, playing football on his high school team.
He says this past season was tough to sit out.
"Watching football on Sundays kind a makes me feel sad because I can't play next weekend or whatever," said Steven Polanco.
The ACL stabilizes the knee. A torn ligament is a common sports injury, typically seen in adults.
Dr. Samara Friedman, at Morristown Memorial Hospital, says these tears are striking little kids' knees, as well.
"Children are participating year round in sports," said Dr. Samara Friedman. "They don't just have one sport that they love, but they have three sports that they are doing it all year round."
Steven will need surgery to fix his ACL, but it's a risky procedure for kids because the growth plate is close to ACL.
Doctors would have to drill into the growth plate, which is an area of developing tissue that determines bone length. Simply put, the bone could stop growing.
Instead, Steven could have surgery where the ligament is wrapped around the knee joint, avoiding the growth plate.
Doctors say it's a promising procedure, but it is still pretty new.
"We don't have any long term follow-up, yet," said Dr. Samara Friedman.
There are no easy answers for children with ACL tears.
For now, Steven will wait and see.
His knee is holding up because of physical therapy, and he's come to terms with putting his football dreams on hold.
