Quadriceps architecture in individuals with patellofemoral pain: a systematic review protocol.

OBJECTIVE: The objective of this review is to identify differences in quadriceps architectural parameters between healthy individuals and those with patellofemoral pain (PFP). INTRODUCTION: Patellofemoral pain is one of the most common causes of knee pain among physically active populations. Muscular imbalance may play an important role in patellar malalignment or patellar maltracking. A systematic review will clarify the possible architectural changes of quadriceps muscles in persons with PFP. INCLUSION CRITERIA: Eligible observational studies will include individuals younger than 50 years who have been diagnosed with unilateral or bilateral PFP. The comparator will be the contralateral, asymptomatic limb of the individual with PFP or a healthy matched subject. Studies that include measurement of quadriceps muscle size as the primary outcome will be considered. Studies in which participants had coexisting pathology, a history of lower limb surgery or injury, or pain originating from other joints will be excluded. METHODS: PubMed/MEDLINE (NLM), Scopus, Embase, Physiotherapy Evidence Database, Web of Science and CINAHL databases and multiple gray literature sources will be searched. Studies published since 1 January 1990 will be considered; there will be no language restriction. Retrieval of full-text studies, assessment of methodological quality and data extraction will be performed independently by two reviewers. If possible, meta-analyses will be performed, and a Grading of Recommendations, Assessment, Development and Evaluation (GRADE) Summary of Findings presented.