Jordana Bieze Foster

May 29, 2009

May 29, 2009 (Seattle, Washington) — A supervised exercise program for patellofemoral pain syndrome (PFPS) more effectively improves pain and function than usual care emphasizing rest and activity avoidance, according to a randomized clinical trial presented here at the annual meeting of the American College of Sports Medicine.

In 131 patients aged 14 to 40 years with chronic patellofemoral pain, Dutch researchers found that those who completed a 12-week exercise program reported significantly lower levels of pain and higher levels of function at 3 months and at 1 year compared with those who received "usual care" from their physicians.

The treatment intervention included exercises for quadriceps strengthening, flexibility, balance, and coordination, progressively increasing in complexity over time. Usual care, consistent with clinical guidelines for general practitioners in the Netherlands, included verbal and written information about patellofemoral pain and recommendations to avoid activities that provoke pain.

"Our outcome supports the use of supervised exercise therapy instead of a 'wait and see' approach," Robbart van Linschoten, MD, a sports medicine general practitioner at Erasmus University Medical Center in Rotterdam, the Netherlands, said during his presentation.

Changes from baseline for self-reported pain at rest, pain with activity, and function were all significantly greater in the exercise group than in the usual care group, both at 3-month and 12-month follow-up testing (p<.05 for all). The change in pain at rest was 1.07 points greater (on a 10-point rating scale) at 3 months and 1.29 points greater at 12 months; change in pain with activity was 1.00 point greater at 3 months and 1.19 points greater at 12 months; change in function was 5.4 points greater (on the 100-point Kujala scale) at 3 months and 4.8 points greater at 12 months. Self-reported recovery, measured using the Likert scale, improved in both groups over time but did not differ significantly between groups at either follow-up point.

One limitation of the study, Dr. van Linschoten said, was that the researchers did not control for patient-practitioner interaction. Because the patients in the exercise group spent more time with practitioners than those in the usual-care group did, it is possible that the encouragement and advice provided during the exercise sessions had a positive effect on outcomes independent of the exercises themselves. Another limitation was that levels of pain, function, and recovery were reported by patients via questionnaires rather than measured objectively.

Previous studies of exercise therapy for patients with patellofemoral pain have been limited in scope and inconclusive in their findings, as reflected in a 2003 Cochrane Review article published by other members of the Erasmus group. The current study, which has been accepted for publication in the British Medical Journal, represents an important step toward filling that knowledge void, said Brian Noehren, PhD, PT, who has been researching the biomechanics of patellofemoral pain syndrome as a member of the University of Delaware's physical therapy program.

"These randomized trials are hard studies to do, and I really commend them for it," Dr. Noehren said in commenting on the Dutch study. "It really give us better evidence that this type of therapy is efficacious."

At an April research retreat on patellofemoral pain syndrome, where the Dutch findings were also presented, a primary theme of discussion involved the need for therapeutic interventions aimed at realignment of the patella rather than short-term relief of symptoms, according to Dr. Noehren.

"So often physicians will just recommend medication or some other kind of self-treatment that addresses the symptoms but doesn't address the root cause of the pain. That's where exercise is important," he said. "Perhaps if we can get to patients earlier, we might be able to reverse some of those symptoms."

An important next step in research will be to look at the contributions of specific exercises, with the hip muscles currently being of particular interest, Dr. van Linschoten said. Because of the variability within the patellofemoral pain population, researchers are also interested in more targeted interventions based on an individual patient's set of symptoms.

"Looking forward, we can do even better by matching exercises to specific subgroups of patients," said Dr. Noehren, who presented his group's positive results with gait retraining for runners with patellofemoral pain. "One set of exercises is not necessarily going to work for everybody."

The PEX study was funded by a grant of ZON-MW(945-04-356). The study authors have disclosed no relevant financial relationships.

American College of Sports Medicine (ACSM) 56th Annual Meeting: Abstract 570. Presented May 27, 2009.


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