New research out of the University of Delaware indicates that patients who have undergone total knee arthroplasty (TKA) need to relearn the proper techniques of moving from a sitting to standing position. The study was originally published in Physical Therapy (May 1, 2008), the scientific journal of the American Physical Therapy Association (APTA).

"Most patients with a knee replacement have been living with severe pain for years," says Dr. Chuck Wolfe, DPT, clinic director of the Mechanicsburg office of First Choice Rehabilitation Specialists. "The patient will apply different coping mechanisms to avoid using their weakened quadriceps femoris muscle (muscle on the front of the thigh) when going from a sitting to standing position," notes Dr. Wolfe.

The study, which evaluated 12 patients three months and one year following total knee replacement surgery, showed that the patients relied on a larger hip extensor movement (leaning far forward to rise) to perform the sit-to-stand task. "This study shows that, even following surgery, the strategies they used prior to surgery had become second-nature to them and they continued as patients' muscle strength improved." says Dr. Wolfe. "It was a learned movement pattern that could not be changed without retraining by a physical therapist, usually beginning 4-6 weeks after surgery when the patient could put weight equally on both legs," he concluded.

The study found that, in order to get up from a chair, patients would bend forward at the hips and use the hips to stand up, moving the center of gravity forward. This makes the task easier, but is less stable and could lead to falls. The retraining would involve teaching the patient to rise up from the chair without bending forward, most likely by allowing the use of the arms to help push up in order to develop the correct pattern and eventually moving to performing the task without the use of the arms. Because the incorrect movement pattern could potentially contribute to the development of future knee osteoarthritis, retraining may be an important prevention strategy.