Evidence-Based Answer
Exercise therapy with quadriceps strengthening reduces pain in patellofemoral pain syndrome (PFPS). Open- and closed-kinetic chain exercises are equally effective in relieving patellofemoral pain. (SOR B, based on systematic reviews.)
PFPS is a common complaint among adolescents and young adults. The etiology of this condition remains uncertain. Multiple causative theories, including malalignment, poor patellar tracking, and tight anatomic structures, have been developed.1
A 2003 Cochrane review compared the effectiveness of various types of exercise therapy with each other or placebo/no exercise, using a primary outcome measure of pain reduction. Twelve studies were reviewed, including 9 randomized controlled trials and 3 concurrent controlled trials without randomization, totaling 697 participants with an average age of 24 years. Two randomized placebo-controlled studies showed that exercise was associated with decreased anterior knee pain compared to no exercise, noted by improvement on a visual analog scale (VAS). Four randomized studies,
including 179 patients, demonstrated equal pain reduction comparing open-chain exercises (in which the foot moves freely through a range of motion, eg, a leg extension for quadriceps strengthening) and closed-chain exercises (in which the foot maintains contact with a surface, eg, a squat).1 All trials cited in the Cochrane review evaluated the efficacy of quadriceps strengthening.
A previous systematic review of 8 controlled trials, including 402 patients, demonstrated similar findings as the Cochrane review: pain reduction with quadriceps strengthening with no significant difference between open- and closed-chain exercises. Also, as in the Cochrane review, studies evaluated the effectiveness of quadriceps strengthening but did not investigate the effect of hip strength and flexibility.2
Recent investigations have focused on the role of hip muscle function in PFPS. One recent prospective cohort study of 35 patients (43 affected knees) found improvements in pain with hip flexor strengthening and increased iliotibial band and iliopsoas flexibility.3 Successfully treated patients demonstrated at least a 1.5-cm decrease on the 10-cm VAS to assess pain with activities of daily living and exercise. Ninety-three percent (14 of 15 patients) had decreased VAS scores with improved hip flexion strength of more than 20% and normalized Ober and Thomas tests after treatment. Further investigations with a larger cohort of patients are warranted to investigate further if controlling femoral rotation via hip strengthening/stretching can improve PFPS.
Marvin H. Sineath Jr, MD, and Darren Campbell, MD
Family Medicine Residency, Eglin Air Force Base, Florida
1. Heintjes E, Berger MY, Bierma-Zeinstra SMA, et al. Exercise therapy for
patellofemoral pain syndrome. Cochrane Database Syst Rev 2006;
(2):CD003472. [LOE 1a]
2. Crossley K, Bennell K, Green S, McConnell J. A systematic review of physical
interventions for patellofemoral pain syndrome. Clin J Sports Med 2001;
11:103–110. [LOE 2a]
3. Tyler TF, Nicholas SJ, Mullaney MJ, McHugh MP. The role of hip muscle function
in the treatment of patellofemoral pain syndrome. Am J Sports Med 2006;
34:630–636. [LOE 2b]