School of Health Professions

Professor pursues clues to treating functional ankle instability

Jun 28, 2012

By Andi Enns

Wen Liu, PhD, associate professor in the KU department of Physical Therapy and Rehabilitation Science and Tarang Jain, PT, PhD student in KU Rehabilitation Science program, display Liu's creation - a rotating foot pad which mimics the movement of an instable ankle.

Wen Liu, PhD, associate professor in the KU department of Physical Therapy and Rehabilitation Science, has obtained funding for research he believes will revolutionize the treatment of ankle instability.  Recently awarded a NIH R21 grant for his application entitled “Revealing an etiological factor of functional ankle instability,” Liu hopes to add new insight to a research topic that hasn’t seen a breakthrough discovery in 50 years.

Ankle instability is a common sports injury, Liu says, and most people who come in under those circumstances are successfully treated. The joint simply becomes loose, and physical therapy fixes the issue by strengthening the muscles. This is called mechanical instability.

“Some patients don’t have an injury to start with,” Liu says. “Those are the ones I’m studying.”

Some patients say they will walk on flat surfaces, such as in their office, and their ankle will give out. Suddenly, they’re on the floor.  Tests show a healthy-looking joint and no amount of physical therapy seems to help – especially because no particular motion led to the fall. It’s frustrating for patients and doctors.

“Basically, we can diagnose the problem as functional instability,” Liu says, “but we don’t know what caused it or how to treat it.”

Liu says he thinks he found a solution.

He developed a way to test the seemingly random ankle instability. Patients wear a safety harness hooked to the ceiling, and hold onto another safety loop. They place their healthy foot on a solid platform, and their instable foot is placed on a device Liu created.  It’s made of plywood, and the foot pad can rotate 30 degrees, which is a moderate slant that mimics the movement of an instable ankle.

The patient is then hooked up to electrodes to monitor their nervous system.  A set of three infrared cameras take photos of the patient during the process.  After settling in, the patient is given a warning before a physical therapist drops the foot pad to 30 degrees and the electrodes minister a small, slightly uncomfortable shock.

Liu says most of the time, the patient’s ankle still doesn’t react – at least the first time. Through this process, he’s been able to capture data of the ankle at the moment of collapsing, and it’s not a joint problem – it’s a problem with the central nervous system.

“It may be hypersensitivity in the nerves around the ankle,” Liu says. “A tiny difference in the floor – unnoticed by most people – will cause a dramatic overreaction. Basically, the nerves around the ankle think they’re in danger and just give up.”

His NIH funding will assist Liu in exploring the nervous system’s role in joint problems.  If his theory is correct, a new world of rehabilitation therapy could open up for patients with functional ankle instability.

“If this theory is correct,” Liu says, “treatment could look similar to treating a phobia.”

He says phobias are treated by forcing the patient to face their irrational fears over and over until they feel in control of it. Likewise, the patient could use Liu’s device to mimic instability over and over until the nervous system realizes it’s not a threat.

“This could have an important impact on the field,” Liu says.

To learn more about Wen Liu's work and the Neuromuscular Research Laboratory, click here.


KU's programs are nationally recognized for excellence as a leader in education and research in the field. A unit of the KU School of Health Professions, the KU Department of Physical Therapy and Rehabilitation Science is located on the University of Kansas Medical Center campus in Kansas City, Kansas. In collaboration with The University of Kansas Hospital adjacent to KUMC, students benefit from the opportunity to interact with a large number of health care professionals and leading researchers in real-world environments.

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