A new five-year grant is funding research into why women are more prone to ACL injuries than men. Duke's Louis DeFrate leads the study with a focus on knee shapes, movement and biological factors that contribute to the disparity.

A new grant is helping Duke researchers unlock mysteries that surround ACL injuries, especially among younger women.

The $3.9 million five-year grant looks to determine why females are more prone to ACL injuries compared to males.

Louis DeFrate is a Laszlo Ormandy distinguished professor of orthopedic surgery with Duke. He is spearheading the new research alongside orthopedic surgeon Dr. Jocelyn Wittstein.

DeFrate explained the disparities between ACL injury risks are extremely prevalent when comparing college-aged females and males.

"Women are something like 10 times more likely to have an ACL tear compared to men," DeFrate said. "Some of the things we're looking at are the shapes of the knees, how women move versus how men move, as well as factors in the blood, biological factors."

DeFrate shared most ALC injuries are non-contact injuries and can have "devastating consequences" down the line.

"Not only can you not play your sports but in terms of osteoarthritis burden, whether you have your ACL reconstructed or not, it's been estimated to age your knee by about 30 years," DeFrate said. "If you've had a prior ACL tear, you're very likely to get another one either in your reconstructed knee or your other knee."

The research will challenge the status quo used to diagnose and subsequently treat injuries.

Unique imaging technology takes multiple scans of an individual's knee as they undergo various physical movements, such as jumping or swatting, to show how the ACL is stretching and what movements could increase injury risk.

"There are some controversies in the literature as to what motions lead to an ACL injury. Some people think it's landing on a straight knee, other people thing it's this valgus collapse or inward buckling of your knee," DeFrate said. "If we can't understand what's causing it to happen, it's a little bit harder to prevent."

Researchers are also questioning if fatigue could be a factor.

The study aims to enroll about 200 adults under the age of 40 and will include both participants with uninjured and without a history of ACL injury.

DeFrate shared the median age of ACL injury is around 17 for males and slightly lower for females.

It's a statistic 17-year-old Addison Pepitone found herself a part of this year after suffering an injury during a fall at a rock-climbing gym.

"I was trying this climb I had been trying to do for a long time and I was very determined to do it," Pepitone said. "I was on the last move, which I hadn't gotten there before, and when I went up, I didn't get all the way there and so I fell."

The competitive rock climber shared she felt like she was falling normally, until pain overcame her right leg.

"Suddenly, I hit the ground and I just felt pain in my knee," Addison said. "It was kind of just a weird sensation because I had fallen like that a million times."

Pepitone's fall was captured on video. In the immediate aftermath, people were slow to come to her as her fall didn't immediately stand out as anything severe.

"Looking in the video, it didn't look like a bad fall so everyone around me was like, 'Are you okay? What's wrong?" she said. "I was just screaming 'My knee! My knee!' They didn't really think anything was wrong."

The teen recalled the athletic trainer on-site even reassuring her that the way she fell wasn't consistent with an ACL tear. But, Pepitone's MRI showed she injured both her ACL and meniscus and would need surgery and physical therapy.

"Obviously we were just hoping, but I think she knew it was more," shared Addison's mother, Katie Pepitone. "We kept trying to hope it wasn't more, but you could tell by the pain she was in that it was more."

The family recalled the initial diagnosis was devastating but meeting Wittstein gave Addison hope of getting back to the sport she loved.

"She said it was very normal for a girl, especially my age, for this to happen," Addison said.

The statement was further underscored by Addison's experience in the waiting room.

"I remember sitting in the waiting room and just girl after girl with the same brace after me," Addison said. "I was like 'Wow.' It's very interesting this is all happening to people like me too."

Wittstein has worked with Addison to find ways to regain her strength after surgery.

Katie Pepitone shared watching her daughter refuse to give up was inspiring.

"It was tough at first obviously watching her go through it and the pain of the surgery, but we've actually never been more proud of her of how she's pushed through," Katie Pepitone said. "Not only the injury, but finding other ways to still climb."

Addison Pepitone noted she also felt "very proud" in her ability to overcome both the mental and physical challenges that have come in the wake of her injury. She hoped DeFrate and Wittstein's research will help prevent other athletes from undergoing the same trauma.

"If through this research we're able to find ways to prevent it, I'd just be very glad we'd be able to help," the teen shared. "Dr. Wittstein has been so helpful. Especially just bringing this issue to light and continuing to fight for why this is happening."

The athlete continued, "I'm excited to continue to have her help me through this and hopefully in the future that she's able to find an answer to help people like me."

Those with previous ACL injuries are encouraged to reach out to DeFrate to discuss how to get involved in the research.