Systematic Review of the Quality of Randomized Controlled Trials for Patellofemoral Pain Syndrome

STUDY DESIGN: Systematic review of the literature. OBJECTIVES: To develop a grading scale to judge the quality of randomized clinical trials (RCTs) and conduct a systematic review of the published RCTs that assess nonoperative treatments for patellofemoral pain syndrome (PFPS). BACKGROUND: Systematic reviews of the quality and usefulness of clinical trials allow for efficient synthesis and dissemination of the literature, which should facilitate clinicians' efforts to incorporate principles of evidence-based practice in the clinical decision-making process. METHODS AND MEASURES: Using a scale based on criteria in the Cochrane Collaboration Handbook, we sought to critically appraise the methodology used in RCTs related to the nonoperative management of PFPS, synthesize and interpret our results, and report our findings in a user-friendly fashion. A scale to assess the methodological quality of trials was designed and pilot tested for its content and reliability. Published RCTs identified during a literature search were then selected and rated by 6 raters. We used predefined cutoff scores to identify specific weaknesses in the clinical research process that need to be improved in future clinical trials. RESULTS: The quality scale we developed was demonstrated to be sufficiently reliable to warrant interpretation of the reviewers' findings. The percentage of trials that met a minimum level of quality for each specific criterion ranged from a low of 25% for the adequacy of the description of the randomization procedure to a high of 95% for the description and standardization of the intervention. CONCLUSIONS: Based on the results of trials exhibiting a sufficient level of quality, treatments that were effective in decreasing pain and improving function in patients with PFPS were acupuncture, quadriceps strengthening, the use of a resistive brace, and the combination of exercises with patellar taping and biofeedback. The use of soft foot orthotics in patients with excessive foot pronation appeared useful in decreasing pain. In addition, at a short-term follow-up, patients who received exercise programs were discharged earlier from physical therapy. Unfortunately, most RCTs reviewed contained qualitative flaws that bring the validity of the results into question, thus diminishing the ability to generalize the results to clinical practice. These flaws were primarily in the areas of randomization procedures, duration of follow-up, control of cointerventions, assurance of blinding, accountability and proper analysis of dropouts, number of subjects, and the relevance of outcomes. Also, given the limited number of high-quality clinical trials, recommendations about supporting or refuting specific treatment approaches may be premature and can only be made with caution.