Study by University of Delaware Department of
Physical Therapy Demonstrates That Patients Need to Relearn Proper Use
of Knee
ALEXANDRIA, VA, June 12, 2008 — New research out of the
University of Delaware (UD) 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).
"Because most patients with knee replacement have lived with
debilitating pain for years, they work around the pain by adopting
different strategies to avoid using their weakened quadriceps femoris
muscle (muscle in front of the thigh) when going from a sit-to-a-stand
position," says Lynn Snyder-Mackler, PT, ScD, SCS, ATC, FAPTA,
distinguished alumni professor in UD's Department of Physical Therapy
and a certified sports physical therapist and athletic trainer who was
one of the study investigators.
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. "What is interesting about the study,"
notes Snyder-Mackler, "is that it shows that, even following surgery,
this strategy continued as patients' muscle strength improved." The
strategy, although dangerous because of the risk of falling, had become
second-nature to them, observed Snyder-Mackler. "Simply put, it was a
learned movement pattern that could not be resolved without retraining
by a physical therapist, usually beginning 4-6 weeks after surgery when
weight can be put equally on both legs," she concluded.
Snyder-Mackler 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,"
concluded Snyder-Mackler.
Physical therapists are health care professionals who diagnose and
manage individuals of all ages who have medical problems or other
health-related conditions that limit their abilities to move and perform
functional activities in their daily lives. Physical therapists examine
each individual and develop a plan of care using treatment techniques to
promote the ability to move, reduce pain, restore function, and prevent
disability. Physical therapists also work with individuals to prevent
the loss of mobility by developing fitness- and wellness-oriented
programs for healthier and more active lifestyles.
The American Physical Therapy Association (www.apta.org) is a
national organization representing physical therapists, physical
therapist assistants, and students nationwide. Its goal is to foster
advancements in physical therapist education, practice, and research.
Consumers can access "Find a PT" to find a physical therapist in their
area, as well as physical therapy news and information at www.apta.org/consumer.