Experts say there's an epidemic of these knee injuries among girls.
[Ads /]
They are getting increasing attention by doctors, and research is underway on surgery that could change treatment for all ACL tears.
Basketball season is in full swing, but Glennyce "Chi Chi" James won't be on the court.
This summer, Chi Chi landed after a rebound during a summer conditioning session...
"I came down on it and I turn, and I heard a pop. And then I kept playing because I didn't care," says James.
That "pop" was actually heard across the gym. Tests later showed James had torn her ACL, the ligament which stabilizes the knee during sudden direction changes.
Dr. Alfred Atanda, Jr., an orthopedic surgeon at Nemours duPont Hospital, says several factors are contributing to the boom in female ACL injuries.
Girls' knees tend to point in more, putting more stress on the joint. They're also playing a lot more sports, more of the year, and at higher levels.
Hormones also play a role and so does age.
[Ads /]
"The peak is probably around 13-14 years of age," says Dr. Atanda.
He says virtually every ACL tear needs surgery.
"We take tissue from somewhere else in your knee, somewhere else in your body or from someone else. And we use that to make a new ACL," says Dr. Atanda.
In James' case, it came from her hamstring.
After surgery, recovery is slow, taking nine months to one year.
"That has to heal into where the old ACL was," says Dr. Atanda.
Boston Children's Hospital is working on a new technique - Bridge-Enhanced ACL Repair - or BEAR.
[Ads /]
A sponge-like implant, saturated with the patient's own blood, is placed between the torn ends, to jump-start healing of the ligament.
"You'll get back in about three months as opposed to nine months," says Dr. Atanda. "It has the potential to completely revolutionize how we treat ACL tears surgically."
So far, the technique has been used in 75 patients, but is still in the testing phase.
Dr. Atanda says to minimize the risk of ACL tears, young athletes should strengthen muscles around the knee and take breaks during the year to let muscles, ligaments, and tendons rest.
He empathizes with athletes with ACL injuries, since he suffered one at age 34.
"I was playing soccer, and I was doing nothing in particular, no different from what I'd done 10,000 times before and then, boom, my ACL tore" said Dr. Atanda.
"I actually gave up sports," he says. "I never played soccer again since that day."