Background: Shoulder ultrasonography is an easily accessible and frequently performed investigation. The frequency of abnormalities on shoulder ultrasonography increases with age and can occur in the asymptomatic population. Thus, abnormalities seen on ultrasonography are not necessarily indicative of clinically significant pathology, compromising the specificity of the test. The objective of this systematic review was to determine the frequency of abnormalities on shoulder ultrasonography in asymptomatic adults, and identify risk factors for abnormal findings in asymptomatic individuals.
Methods: A systematic literature search was conducted of three databases (Medline, Embase and PubMed) using the following key terms, MeSH and free text, in combination: “asymptomatic” and “shoulder” and “ultrasonography OR ultrasound OR sonogram.” Retrieved titles were screened by title. The abstracts of candidate papers were then considered. Full text retrieval of relevant studies were obtained for final assessment for inclusion. The search results were considered independently by both authors, and disagreements resolved by consensus. Original studies were included if they permitted the extraction of shoulder ultrasound findings in asymptomatic individuals without prior trauma, shoulder surgery or inflammatory joint disease. Data extraction used a custom designed data extraction tool. Collected data includes the type and design of study, number of participants, outcome measures (including definitions) and ultrasound methodology. The methodological quality of the studies was assessed using a Critical Appraisal Tool (QUDAS-2). Descriptive statistics (ie. proportion and confidence intervals) for different findings will be reported overall and in 10-year age bands. Factors associated with pertinent imaging findings will be assessed using univariate analysis and significantly associated factors will be studied in a multivariate analysis.
Results: The initial search retrieved 287 titles after elimination of duplicates. 259 articles had their abstract reviewed and 28 articles were retrieved for assessment for inclusion. Twenty-two studies met inclusion and exclusion criteria. Data extraction from these studies is currently in progress.
Conclusion: We anticipate reporting on the prevalence and determinants of shoulder ultrasonographic abnormalities in asymptomatic individuals, including rotator cuff pathology (tendinopathy, full/partial rotator cuff tears), bursal pathology and long head of the biceps tendon disorders.