Stanford doctors replaced his knee joint, with his ankle and foot. Now, Chris wears a prosthesis that fits snugly around his residual limb.
PHOTOS: Elk Grove boy recovers after rare knee surgery
In the last 20 years, Lawrence Rinsky, M.D., has performed only 10 of these rare surgeries. "It acts totally as a knee. The amazing thing is that the muscles of the calf, which then become the front muscles of the thigh are more or less in tune with working at the right time, they have to adapt a little bit," he said.
"So we explained to him, you know it's going to look like this and I still remember Chris' response was 'who cares what it looks,'" Chris' father Jese Formaker said.
"I can run fairly well, still getting a little better. I can jump, I can walk about as good as I could before the surgery," Chris said.
Chris's journey began in January of 2015. At the time, he was active in basketball, soccer and baseball. When he began experiencing knee pain and swelling, Chris's parents assumed it was due to a sports-related injury and scheduled an appointment with his pediatrician near their home in Elk Grove. "I picked Chris up from school on a Thursday afternoon for the appointment, and he didn't return to school for a year," Jesse said.
Chris was diagnosed with osteosarcoma, cancer of the bone, in his left femur. Osteosarcoma is the most common type of bone cancer among children, typically occurring in the arms, legs or pelvis. Treatment can include chemotherapy, radiation therapy, amputation and other surgeries.
Within a month of his diagnosis, Chris had begun chemotherapy and learned that he would require surgery to remove the malignant tumor in his leg. Doctors presented three surgical options: a series of limb salvage procedures, an above-the-knee amputation or a rarely performed complex rotationplasty procedure.
Rotationplasty is an alternative form of amputation in which the central portion of the leg is removed as surgeons carefully extract the bone tumor present within the femur along with sections of the tibia. In its place, the patient's foot and ankle, turned 180 degrees, are attached to the upper thigh. Surgeons reattach skin and muscle to position the patient's backwards-facing foot at equal height to the opposite remaining knee. Once healed, this serves as a new knee joint and can be comfortably fitted with a prosthetic leg.
"Aesthetically, there's no question - rotationplasty looks funny," said Larry Rinsky, MD, chief emeritus of pediatric orthopedic surgery at Stanford Children's Health. "But it has many advantages, particularly for kids like Chris who want to maintain mobility and continue playing sports. It is truly a long-term solution to a difficult problem."
Six months after surgery, Chris was both concluding chemotherapy treatment for his cancer and beginning to bear weight on his new leg. Working with Gary Berke, MS, CP, an adjunct clinical assistant professor of orthopedic surgery at Stanford University School of Medicine, Chris was fitted for a prosthetic leg that fit over his new knee joint, allowing him to return to the sports that were such a part of his identity.
Less than two months after Chris received his prosthetic leg, his family brought him to a basketball clinic for amputees. Their plan was for him to observe the game and get idea of what he would be able to do once he made a full recovery. But Chris had another idea. With his arms outstretched toward his father, crutches in hand, he said: "Hold these, dad."
"He was in such pain. He could barely walk. He would fall down and I'd have to go pick him up," Jesse said. "But he was determined and the next thing we knew he was out there dribbling and shooting like old times."
Now, Chris is playing basketball in the same recreational basketball league he was part of before his diagnosis - the Cosumnes CSD Junior NBA basketball league.
His favorite player in the NBA is Warriors star Steph curry, who he met in 2015. "I got Steph Curry's jersey that he had just worn in practice and it hasn't been washed," Chris said.
Chris's family says that as a result of being able to play sports again, he pushes himself to achieve. "The day Chris was diagnosed with osteosarcoma was the worst moment of our lives," Jesse said. "You never want to imagine going through that, but we didn't get to make that choice. We did, however, get to make the choice for Chris to have a rotationplasty, and for that we could not be more grateful."