Drs. Turnbull and Mehner pose standing on a staircase
Marion (Toni) Turnbull, Ph.D. (left) and Christine Mehner, M.D., Ph.D. (right)

Editor's Note: This article is the third in the Young Innovators series, originally published in Mayo Clinic's Alumni Magazine. Each article features Mayo Clinic trainee inventors and explores their journeys as biomedical entrepreneurs. All of these trainees say their goal was to improve health care for patients.


When she was an orthopedics resident in her native Germany, Christine Mehner, M.D., Ph.D., noted that the nails used to set fractures didn’t provide the best possible outcomes to stabilize fractured long bones, such as the tibia, femur and humerus. In standard surgery to fix a tibia fracture, for example, a surgeon’s experience determines adequate positioning of the patient’s leg and foot to achieve proper alignment post-surgery. However, in more than 40% of cases, patients have an error in the rotation of the foot after surgery. A rotation error of more than 30 degrees from its original position can negatively affect the patient’s knee, hip and ankle over time.

Four years later, when Dr. Mehner was a predoctoral Ph.D. student at Mayo Clinic in Florida, the fracture nail issue resurfaced. She and her colleague Marion (Toni) Turnbull, Ph.D., a New Zealand native who is a research associate in the Department of Neurology, were brainstorming ideas for Mayo Clinic in Florida’s Alligator Tank competition in which aspiring entrepreneurs and inventors pitch ideas to a panel of expert judges.

We believe ours could make surgery easier and faster for surgeons. More importantly, the nail could help patients
heal faster and with less pain.

Christine Mehner, M.D., Ph.D.

“Too much manual manipulation of the leg and foot during surgery can cause damage, which increases pain and recovery time and detracts from healing,” says Dr. Mehner, now a postdoctoral fellow at Mayo Clinic in Florida. “Considering the long-term impact that common rotation errors can have, we thought there must be a better way.”

Drs. Mehner and Turnbull pitched the concept of an adjustable fracture nail, which has internal rotating mechanisms and components that allow the nail to extend and fine-tune the angle of the fractured limb while in the bone. The patented nail is being prototyped with Mayo Clinic’s Surgery Research Center for Excellence. With help from Mayo Clinic Ventures, the inventors hope to find a surgical device company to produce and test the nail in a patient cohort.

Close up view of adjustable fracture nail
Adjustable Fracture Nail

“The fracture nails currently in use have been the status quo for decades,” says Dr. Mehner. “We believe ours could replace current intramedullary nails and make surgery easier and faster for surgeons. More importantly, the nail could help patients heal faster and with less pain, reduce the risk of permanent injury and chronic pain, and reduce the rate of revision surgery.”

An undergraduate class at the University of Minnesota completed a market analysis for the new fracture nail, which has generated enthusiasm from Mayo Clinic orthopedic surgeons. Dr. Turnbull says, “They’ve said they can’t believe it doesn’t exist already.

“When you can’t believe there’s not a better way to do something, look at that as an opportunity for innovation. Mayo Clinic has resources to help with patent disclosures, inventor forums, support and seed funding.”

Mayo Clinic in Florida’s “I’m In” campaign encourages innovative thinking, continuous improvement and challenging the status quo. Employees and staff at all levels are urged to think differently, identify problems and generate solutions to everyday challenges.

“There’s a growing entrepreneurial community on the Florida campus,” says Dr. Turnbull. “Once you let people know that innovative ideas will be supported and provide the right culture, more will come. We are already thinking of ideas to improve research and patient care.”

The adjustable fracture nail received a 2021 Innovation Accelerator Award from the Mayo Clinic Office of Translation to Practice, which awards projects that aim to develop new products with commercialization potential.