Assisting Arthritis Patients to Walk After Hip-Replacement Surgery Focus of UB Study

Release Date: November 7, 1996

BUFFALO, N.Y. -- Developing new methods to correct unhealthy walking patterns in patients with degenerative joint disease who have received hip replacements is the focus of a study being conducted at the University at Buffalo.

According to Scott White, lead researcher for the study and an associate professor in the Department of Physical Therapy and Exercise Science, the number of hip replacements performed in the United States exceeds 150,000 per year. "If this research can help reduce health-care costs, this could have an immense economic impact and change treatment for arthritis patients," said White.

The UB study is being funded by a $201,000 three-year grant from the Arthritis Foundation.

To reduce pain when walking, patients with degenerative arthritis in one hip are apt to reduce force on the painful hip, which tends to increase force on the opposite side of the body. Since some patients with this type of arthritis often postpone surgery for a number of years, explained White, this walking pattern can become an unhealthy habit. Even after surgery, some patients continue to walk while applying uneven amounts of force on each side of the body.

"Patients with a compensatory walking pattern place abnormal force on otherwise healthy joints, which could potentially cause a secondary injury," White said. "We are trying to determine if we can correct the movement pattern to stop the patient from using the adaptive strategy."

White and Robert Lifeso, co-investigator of the study and a clinical professor in UB's Department of Orthopedic Surgery, have devised for the study a technique, called real-time dynamic visual feedback, aimed at changing the walking pattern of patients who have had a single hip replacement.

The challenge in correcting an awkward walking pattern, noted White, is that it is caused by body motions generated by "forces you cannot see." Visual feedback of these forces while walking on a treadmill allows patients to see how forces are applied by each side of the body.

A treadmill designed by Kistler Instruments Corp., and equipped with force plates, is being used to measure such forces step-by-step. They are displayed on a screen located in front of the treadmill so that the patient can visualize and understand how much force is being placed on each side of the body and attempt, with the assistance of a therapist, to correct the walking pattern.

"By giving a patient information about the amount of force used while walking and with some coaching, we're hoping to help the patient recover a normal walking pattern faster and reduce the potential for secondary joint problems to develop," said White.

Individuals who have had hip replacement due to unilateral degenerative arthritis and are interested in participating in the study should call 829-2941, ext. 103.