United States Eventing Association

In many ways, 12-year-old Adelaide “Addie” Singleton (Arden, North Carolina) is just like any other horse-crazy young girl. She spends every spare second at the barn where she rides, Wren Song Equestrian, which thankfully is right in her backyard.

“She just could not get enough of the horses,” said mom Emily Singleton. “She would go work at the barn every day and was working towards learning to jump with a horse named Lyric and preparing to event, and then she was diagnosed with cancer.”

Addie was 11 when a sore knee led her to a doctor’s appointment that had every opportunity to shape her life in various ways, but the one thing Addie wasn’t going to let it do was stop her from riding.

“I was at a student camp, and I stood up and felt a pop in my knee,” said Addie. “And from then on, I had really bad pain, but we just thought it was a sprain, so we iced it and took Ibuprofen. It was hurting so bad that we went to an emergency orthopedic, and he took some X-rays and looked a little worried, so he sent me off for an MRI.”

“They found a tumor in the top of her left tibia,” Emily recalled. “She was diagnosed with a rare bone cancer, osteosarcoma, and within one week, she started chemotherapy. Overnight, her world shifted from riding lessons and horse dreams to chemotherapy, hospital stays, surgeries, and months of rehabilitation.”

While Addie couldn’t ride until after her tumor was removed, she spent every day that she felt well enough at the barn just being around the horses there. Emily said watching the way she interacted with the horses, and how they responded to her, brought a lot of light to a very dark time.

“It was so incredible to watch. When you have a relationship with these horses, they know exactly what’s going on with you, because they see you day in and day out. There was one who was very affectionate towards her, and we actually have a photo of him licking her left knee right before she had surgery, right in the same spot as her tumor,” she noted.

“It just gave me a lot of peace going to the barn,” Addie reflected. “Like the smell of the horses and the barn, and being around all of the horses and miniature donkeys, it felt so good to be with them.”

And then came one of the most difficult decisions following her diagnosis: deciding what sort of surgical procedure she wanted to undergo.

“We had a few options,” said Emily. “But if I am being honest with you, they all sucked. There wasn’t one easy decision."

Addie opted to do a very rare surgery that is only executed in the United States 20 to 25 times a year called a rotationplasty. During the procedure, surgeons removed the portion of her leg containing the cancer, including her knee joint. Her lower leg was then rotated 180 degrees and reattached, allowing her ankle to function as a new knee joint within a prosthetic leg.

While rotationplasty is uncommon, it offered Addie something incredibly important to her: the potential for an active life. She chose this surgery with the hope that she could not only walk again, but return to riding horses, jumping, and pursuing the dreams she had before cancer entered her life.

After surgery, Addie was fitted with a specially designed prosthetic that fits over her rotated foot and leg. Because her ankle now functions as her knee joint, she is able to bend and control the prosthetic in a way that provides remarkable mobility and function. Compared with an above-knee amputation, rotationplasty can offer greater control of a prosthetic and the potential to return to a highly active lifestyle.

For Addie, that meant the possibility of getting back to the things she loved most—especially riding horses. Some of the unexpected challenges have been surprisingly ordinary ones, like finding boots that that work with her prosthetic and figuring out how to adapt her stirrups for riding.

“My knees are uneven now, so we had to work to figure out what stirrup length was right for me,” Addie noted.

Her operation took place on Nov. 28, 2025, and by Jan. 9 of this year, Addie was back on that same horse, Lyric, who she had been learning to jump with just prior to her diagnosis. But just riding around couldn’t scratch the itch for Addie. She wanted more.

In May of 2026, after nine months of chemotherapy, Addie completed her treatment and has no evidence of disease. She was connected with the Make-A-Wish Central & Western North Carolina chapter, and while other kids might wish for a vacation or a chance to meet their favorite celebrity, Addie’s wish was the wish of a true equestrian.

“She wished for a horse of her own,” said Addie’s mom. “While Make-A-Wish doesn't buy horses for kids, they were willing to help lease a horse."

That dream came true as of Aug. 1 through a six-month lease with a very special horse.

"Lyric’s owner has been with our family through this entire process," shared Emily. "She was so gracious to allow Addie to have jumping lessons on Lyric, and she was the first horse she rode after surgery. She just had this relationship with her, so in June, the week Addie went to have her port taken out, Lyric’s owner, Leslie, came to us and said that she was thinking it was time for her to move on to another horse and would Addie be interested in leasing Lyric. We never imagined that the lease would be with Lyric!"

Addie has already been making the most of her time with Lyric, riding two to three times a week, and getting stronger with each ride. While learning to ride with her new prosthetic has posed its own challenges, Addie hasn’t let that slow her down—she resumed jumping in early July.

Trainer Eugenia “Bean” Adams has been with Addie every step of the way.

“No child should have to go through what Addie has been through. She is the sweetest kid and works her butt off at the barn," she said. "Through the chemo and the surgery, nothing dimmed her light. She has been so inspiring to be around. She is so determined and so much fun to teach. She has this natural instinct, plus this resilience, determination, and inner strength that has helped her through this.

“Bean’s been wonderful,” said Addie. “I love her so much. I am her first adaptive rider, but she has helped me a lot through finding what’s comfortable for me so that I can still ride.”

When Addie’s best barn friend Nora Baumeister qualified for this year’s USEA American Eventing Championships (AEC) presented by Nutrena Feeds, she knew she wanted to tag along. The USEA was beyond proud to gift her a non-compete number and a stall so that she and Lyric could join in on the AEC fun. The girls are spending their week hacking around the beautiful Kentucky Horse Park together when Addie isn’t busy cheering Nora on.

“Being here at the [USEA] American Eventing Championships means more than words can express,” said Emily. “Eventing has always been Addie's dream, and although she isn't competing yet, she's here surrounded by the community that has inspired her through every step of her journey. Her story is a reminder that sometimes healing comes in unexpected ways, and for Addie, horses have been far more than a sport—they've been hope, healing, and the promise of a future she once feared she might lose.”

The USEA is proud to celebrate Addie in a special ceremony which will take place right before the kickoff of the $60,000 Adequan USEA Advanced Final on Friday evening.

About the USEA American Eventing Championships (AEC)

The USEA American Eventing Championships (AEC) presented by Nutrena Feeds is the pinnacle of the sport at the national levels. Held annually, the best junior, adult amateur, and professional competitors gather to vie for national championship titles at every level from Starter to Advanced. This ultimate test of horse and rider draws hundreds of combinations from around the country to compete for fabulous prizes, a piece of the substantial prize money, and the chance to be named the National Champion at their respective levels. In fact, the 2021 AEC garnered over 1,000 entries and now stands as the largest eventing competition in North American history. The 2026 USEA American Eventing Championships presented by Nutrena Feeds will be held on Aug. 25-30 at the Kentucky Horse Park in Lexington, Kentucky. Click here to learn more about the USEA American Eventing Championships.

The USEA would like to thank Presenting Sponsor: Nutrena Feeds; Advanced Final Title Sponsor: Adequan; Platinum Level Sponsors: Bates Saddles, Marshall+Sterling Equine Insurance; Gold Level Sponsors: ARMA, Gallaghers Water, PulseVet, Schneiders Saddlery, SmartPak, Standlee; Silver Level Sponsors: Auburn Labs, Kerrits, The Jockey Club Thoroughbred Incentive Program, Rood & Riddle; Bronze Level Sponsors: 70°, Antech Diagnostics, Athletux, The Chronicle of the Horse, Devoucoux, D.G. Stackhouse & Ellis, Dubarry of Ireland, Equestrian Team Apparel, Foxhollow Farm, Grayson-Jockey Club Research Foundation, Retired Racehorse Project, Ride EquiSafe, Santa Cruz Animal Health; Contributing Level Sponsors: AnimaSol, CrossCountry App, Kentucky Equine Research, LV Harkness, Only Fools and Horses, #WeRideTogether, YETI; and Prize Level Sponsors: ARRO Helmets, The Dad Den, Dandy Products, Equiluxe Tack, Equine IMED, FLAIR Equine Nasal Strips, I Love My Horse Boutique, The Infused Equestrian, Love Equestrian, Majyk Equipe, Mare Modern Goods, Natalie Hummel Coaching, Neighborly Tack, Outlaw Nutrition, Parkmore Supplements, Peak Performance Equine Spa, Poseidon Animal Health, Rachel Dory Fine Art, Right Path Equestrian, Saddle Bird Boutique, Sidelines Magazine, Strides For Equality Equestrians, STRIDER, Stylish in the Saddle, VTO Saddlery, and XLR8 Equine.

About the $60,000 Adequan USEA Advanced Final

The $60,000 Adequan® USEA Advanced Final will take place at the 2026 USEA American Eventing Championships presented by Nutrena Feeds at the Kentucky Horse Park in Lexington, Kentucky on Aug. 26-28. Thanks to Adequan’s amazing support, the Adequan® USEA Advanced Final will bring together the country’s top riders to vie for $60,000 in prize money and the title of Adequan® Champion. To qualify for the $60,000 Adequan® USEA Advanced Final at the AEC in 2026, competitors will need to complete a minimum of two events without cross-country jump penalties at any USEA recognized Advanced horse trials, CCI4*-S, CCI4*-L , CCI5*-L, World Championships, or Olympic Games. Click here to learn more about the $60,000 Adequan® USEA Advanced Final.