Stars of Stanford Medicine

Snap, crackle, pop: Anthony Behn tests new ways to repair broken bones, tendons and ligaments for Stanford surgeons

Anthony Behn sees the human body through the eyes of a mechanical engineer. Bones are beams. Ligaments are linkages. Tendons are pulleys. And all these components can be described with the mathematics of engineering and physics, then modeled on a computer and tested in a lab for strength, flexibility and failure modes.

In the School of Medicine, Anthony is the go-to guy for orthopaedic faculty, fellows, post-docs and students who have questions about the effectiveness of techniques for repairing broken bones, tendons and ligaments.

For example, an orthopedic surgeon who fixes sports injuries asked Anthony to collect data on which surgical technique was better for repairing and stabilizing a torn ankle ligament — a modified Broström-Gould FiberWire suture (picture B, C) or a soft suture anchor (picture D, E). 

Once Anthony had a deep understanding of the surgeon’s clinical question, he designed an experimental protocol and built a test rig. He then obtained 10 size-matched cadaver ankles and had the surgeon suture half the ankles one way and half the other. Each ankle was repeatedly twisted on the mechanical test rig until the ligament failed. Based on this experiment, he found that there was no significant difference in failure rates between the repair techniques. Afterwards, the research team published the results in The American Journal of Sports Medicine so that other surgeons would know that either technique could be used without compromising patient care.

“Anthony’s creative mechanical testing of musculoskeletal repairs has helped the department receive international recognition,” said Robert "Lane" Smith, professor of orthopedic surgery, emeritus.

“His work ethic is extraordinary,” added Morisa Guy, the department’s director of finance and administration. “If only I could clone him.”

Today Anthony and Tim Thio, a new engineer in the lab, support about 20 faculty members. Together they juggle 10 to 12 projects at a time. Other experiments that they’ve worked on include a comparison of plates versus screws for mending broken bones, and a stress-test of two suture techniques for repairing hand tendons. Anthony is currently reviewing thermodynamics principles in preparation for a heat test of a polymer shoulder implant under long-term body-temperature conditions.

Anthony arrived at Stanford in 2010 with an undergraduate degree in mechanical engineering from Cal Poly and a structural and mechanics master’s degree from UC Los Angeles. It was his first job after college, and he admitted that it was a bit intimidating to be shown the empty room in the Edwards Building where he’d have to design an orthopaedic test lab from scratch.

“It was on-the-job training,” he said, as he began setting up and learning how to use all the equipment, including a computer-controlled milling machine, a bandsaw, force transducers, movement detectors and a fatigue testing rig.

The things that Anthony loves the most about Stanford is the variety of work and the culture of lifelong learning. He takes full advantage of the “Stanford Sweetener” benefit that allows staff members to audit classes at the university. Six years ago, while taking a biomechanics course, a female mechanical engineering student sat next to him and smiled. They became best friends, and five years later they married. It was sort of a course with benefits.   

Story and photo by Kris Newby. Illustration by Nick Miller, courtesy of Anthony Behn and The American Journal of Sports Medicine.