A Systematic Review of Reviews in Patellofemoral Pain Syndrome. Exploring the Risk Factors, Diagnostic Tests, Outcome Measurements and Exercise Treatment

Abstract

Background: Literature has shown a growing number of published studies on Patellofemoral Pain Syndrome every year. The increasing evidence base has revealed a significant number of reviews which makes it confusing for clinicians and researchers to choose from the best evidence. This study aimed to gather the reviews on Patellofemoral Pain Syndrome and provide information about the most common clinical tests, risk factors, exercise treatment and outcome measures. In addition, secondary questions aimed to report the study settings and patient characteristics of the primary included studies. Methods: Studies eligible for this Review of Reviews were those published from 1993 to July 2013. Databases searched included PubMed, CINAHL, SPORTDiscus, Pedro and the Cochrane Library. Four key areas were searched using the words: PFPS, Anterior Knee Pain (AKP) or Chondromalacia patella (CP), plus a keyword. The keywords for the four research topics were a) risk factors; b) exercise treatment; c) diagnostic clinical tests and d) psychometric outcome measurements. Only reviews with clear methodological strategy were included. A two-stage evaluation was performed in each review assessment. At first, the level of evidence was graded and then the methodological quality of each review was assessed. Results: Full text screening revealed that only 18 reviews were eligible for use. The selected reviews included 213 primary studies. After excluding duplicates, 144 primary studies were screened to answer the secondary questions. A gold standard clinical test for PFPS assessment cannot be reached and the use of functional tasks should be considered. The quadriceps strength deficits are still the only evidence based risk factors along with the dynamic malalignment of the lower limb. More research is still required on strength and flexibility deficits of other lower limb muscles. The quadriceps-based exercises are still the only ones to have strong evidence together with hamstrings, quadriceps, gastrocnemius and anterior hip muscles stretching. Finally, the usage of Activities of Daily Living Scale is recommended as the best outcome measure. Conclusion: There is no evidence on whether the above treatment and assessment methods should be used in sedentary people or differently across population groups or gender. More RCTs with large populations, powered correctly, in clinical environments are called for in further research.