Olympic athletes share heartbreak and comeback after ACL injury

When Angel City Football Club’s Jun Endo moved to get away from a defender at a preseason training camp in February, her left cleat got stuck in the grass, but her knee kept turning.

“It was very painful,” Endo later told USA TODAY. She had injured other parts of her knee in the past, but she knew this time was different.

Endo started playing soccer when she was 2 years old and had dreamed of playing in the Olympics almost as long. She competed for Japan in the 2020 Tokyo Olympics, where her team finished eighth out of 12. She was looking forward to redemption for her country in 2024.

But MRI results in February showed she had torn her ACL, one of four ligaments that holds the knee together. It attaches to the top of the shinbone (tibia) to the bottom of the thighbone (femur) in the knee.

The 24-year-old was in for a long year. She underwent surgery for the first time and faced a nine-to-12-month recovery, foiling her chance at a second Olympic run and forcing her to miss the entire 2024 season with Los Angeles’ Angel City.

Hundreds of thousands of ACL reconstructions are performed each year in the United States, according to research published in StatPearls.

At least 15 athletes, mostly women and half of them female soccer players, have been sidelined from the Paris Olympics because of it.

Various studies have shown female athletes are at a higher risk of injuring their ACL compared to male athletes, including a statistical survey by the National Collegiate Athletic Association that found risk was up to eight times higher for females.

A common injury and a long road back

A 23-player squad can expect to see three ACL injuries over four years, according to a study by the Union of European Football Associations. In less than six months between November 2023 and April 2024, Australia’s national women’s team lost Sam Kerr, Amy Sayer and Holly McNamara. Kerr's most recent ACL injury is a career second. Her first happened in her other leg and forced her to miss the 2012 London Olympics.

This year, WNBA rookie Cameron Brink injured her ACL a month before she was going to make her Olympic debut on the U.S. women’s basketball 3x3 team. She was replaced by Los Angeles Sparks teammate Dearica Hamby.

Research published in 2020 in the Journal of Orthopaedic & Sports Physical Therapy, concluded that athletes who return to sport before nine months have a higher risk of sustaining another ACL injury.

Just a few weeks before the Paris Olympics, Kawhi Leonard of the L.A. Clippers was replaced on Team USA after USA Basketball, the Clippers and Leonard's representation decided it would be best if he didn't play in the 2024 Paris Olympics. The 33-year-old reported inflammation in his right knee, the same knee that he tore his ACL in 2021 and tissue called the meniscus in 2023.

The day before leaving Team USA in Las Vegas, Leonard told USA TODAY his advice to others dealing with this injury: “Make sure you don’t skip days on your rehab, stay patient, and that’s all you can do. Whatever happens, happens. Don’t leave no regrets throughout your rehab. Make sure you take care of yourself.”

For Endo, soccer is her identity, and living without it has proved challenging both physically and mentally. She had her surgery in California, thousands of miles from her home and family and had to relearn how to walk by regaining range of motion, reactivating her quad and rebuilding the muscle lost from surgery in her left leg.

The strain of it all led her to another first: meeting with a clinical psychologist.

Researchers have found that patients can suffer mental health challenges like depression after ACL surgery, with one study reporting 42% of patients were diagnosed with depression after ACL reconstruction.

Holly Silvers-Granelli, a physical therapist who was part of the research group that developed the Prevent Injury, Enhance Performance program and FIFA 11+ warm up program for injury prevention, said half of healing from ACL injury is physical – rebuilding biomechanics and strength, and the other half is psychological. “The brain is a critical component to the return to training," said Silvers-Granelli, who explained that if the brain is “preoccupied”  with the injury, then it could potentially increase secondary injury risk.

An epidemic in women’s sports

Jo Hannafin who has been a team physician for professional sports teams and at the Olympics, said the ACL is important for controlling rotation of the knee.

“Any time you plant and turn what keeps your knee from coming apart when you twist is your ACL, and that's the reason why that ligament is so commonly injured in planting and pivoting sports and activities,” said Hannafin, who retired from clinical practice as an orthopedic surgeon in 2021 and serves as the vice chair of the Institutional Review Board at the Hospital for Special Surgery in New York City.

In Hannafin’s 31 years as an orthopedic surgeon, she said she performed 10 to 12 ACL surgeries a month, calling the injury an “epidemic” in women’s sports. She suffered the injury herself, which inspired her career as an orthopedic surgeon. Three years after she tore her left ACL, she competed in the 1984 World Championships for rowing.

Experts have suggested multiple reasons why girls and women injure their ACL more than boys and men, including anatomy, hormones and even genetics.

“Research has shown that women have wider hips, which can affect their knee joint alignment when they're landing, and they tend to land in a more upright position, which puts their knees in a straighter position, and they engage their core less,” said Christy Collins, president of the Datalys Center for Sports Injury Research and Prevention. “And we've also seen in previous studies that elasticity of collagen in the knee can change during the menstrual cycle.”

Options for surgery

There are different ways to reconstruct an ACL. Hannafin's was sown back together in a procedure called a primary repair. Although hers remained intact, she said this method has fallen out of favor after studies showed increasing failure rates over time.

Other options for ACL reconstruction include autograft or allograft. An autograft uses the patient’s own tissue, taken from elsewhere in their body, typically their patellar tendon, quad or hamstring. Endo's ACL was reconstructed using part of her quad tendon.

An allograft is tissue from a deceased donor.

Autografts are usually the graft of choice for young people, generally those under 40, because the risk of reinjury is lower than with allografts. The use of quadriceps tendon have gained popularity because there’s less risk of donor-site morbidity, such as general pain, discomfort or decreased function like loss of range of motion.

A newer technique called the Bridge-Enhanced ACL Repair (BEAR) uses an implant to help a torn ACL heal itself by bridging the gap between the torn ends of the ligament. Although Hannafin thinks BEAR could be a great option, she still thinks more long-term studies are needed.

Making a comeback

When WNBA star and Olympian Kia Nurse wakes up in the morning, she knows her right knee is not like the other. Some days it’s sorer after practice or stiffer after traveling than her other knee.

She tore her ACL while playing for the Phoenix Mercury after planting her right foot on a layup attempt in the first 40 seconds of a playoff game against the Las Vegas Aces on Oct. 6, 2021. She fell to the ground in agony, clutching her right knee, before being picked up and assisted off the court. MRI results showed she also had two small meniscus tears, which is cartilage in the knee that acts as a shock absorber.

Nurse spoke with USA TODAY about her ACL injury just days before watching Los Angeles Sparks teammate Cameron Brink injure her ACL on June 18 in a similar way – a noncontact fall to the ground while driving to the basket.

Nurse decided to have part of her quad tendon used to reconstruct her ACL.

She received plenty of advice heading into her long recovery, including from former NBA player Jarrett Jack, who underwent ACL surgery as a player in 2016.

“He said every day is your game day,’” Nurse said. “And that kind of stuck with me because every day that you're in ACL rehab, like you don't get to play games. So at the end of each day, what did you accomplish?”

Early in rehab sometimes that meant something as simple as extending her leg and bringing it back in.

“It's really boring and it's not something you want to do for three sets, but you do it and you kind of treat that like it's your game and then you've accomplished something that day,” she said.

After 11 months of physical therapy six days a week, Nurse was cleared to return to playing basketball. She competed in the World Championships for Team Canada in 2022, which finished in fourth place. She ranked second on the team in scoring with 11 points per game.

“The first year, though, physically, it felt pretty good, mentally was kind of like the biggest hurdle of kind of feeling like you didn't really feel like yourself,” Nurse said of her 2023 WNBA season where she averaged 6 points and 20 minutes per game. She had averaged 10, 12 and 14 points in nearly 30 minutes per game in 2019, 2020 and 2021, respectively.

In 2024, Nurse was traded to the Los Angeles Sparks, and the 28-year-old said this season has been a flip of the switch for her, averaging 8 points per game halfway through the season. Her training is different than it was prior to her injury, and she also works with a nutritionist to maintain a diet that reduces inflammation.

“I can't just go on the court anymore like I used to when I was younger,” she said. “I'm very intentional about activation and mobility and in terms of what I need to activate prior to a game.”

Injury prevention can help but not solve the problem

Injury prevention programs, like FIFA 11+ warm up, have been shown to reduce the risk of ACL injury. “Neuromuscular training really improves lower body strength and control, so they can change that speed and direction safely,” Collins said.

Hannafin also noted that jump-landing training can be highly effective for ACL injury prevention. Neuromuscular training programs have been found to reduce a first ACL injury by between 44% and 73%.

But when it comes to sports that see high rates of ACL injuries like basketball and soccer, “ultimately, injuries are going to happen to everybody, even if they're very well trained, because it's a sport that requires aggressive cutting and pivoting,” Hannafin said.

While Endo is expected to return to soccer next season with Angel City, Nurse is competing in her third Olympics, her first with this new ACL.

This article originally appeared on USA TODAY: Olympic athletes share heartbreak and comeback after ACL injury