That dreaded pop, followed by searing pain is the tell-tale sign of a torn ACL, the anterior cruciate ligament, which helps control the back and forth motion of the knee.
"It was during a soccer game and I was running to get the ball, and a girl from behind pushed into me and I twisted my leg and heard it pop, my knee, it hurt really badly," said 15-year-old Nicole Svantner.
"Twenty years ago, we saw maybe one child a year under 12 years old with an ACL tear. It was really a rare event, an uncommon event," said Dr. Daniel Green, Pediatric Orthopedic Surgeon at Hospital for Special Surgery.
Green said he now sees pre-teen and teen patients with ACL tears weekly.
In New York, the rate of pediatric reconstruction surgeries has more than doubled over 20 years.
"The younger athletes are getting more opportunity to play sports at a higher level, more opportunities in terms of hours per week, month per year, sports specific camps," said Green. “Their neuromuscular skills are still in development. They cannot run, jump, even squat as effectively and safely as they can when they are 18, 19.”
Historically an ACL tear would often end a young player's athletic career, because surgeons would wait for their bodies to mature to operate.
"Then they are having their surgery three years later with a new MRI, and there was just really devastating long term injuries to the knee that happened during that waiting period," added Green.
In a paper Green published in the American Journal of Sports Medicine, he found that operating shortly after injury was better for kids.
"It is a really high rate of success of getting kids back to the sport they want to. It is over 90 percent," he said. "Nicole had her surgery and a year later she's taken up golf, but has no plans to return to soccer.
"It was painful. I don't want to go through it again," Svantner said.
There is a five to 10 percent chance of re-tear with kids who return to high pivot sports like soccer, basketball, skiing and lacrosse, post-surgery.
Green said better prevention is needed, something Nicole's mom Josephine Svantner wants to see happen more in schools and traveling teams.