Diagnostic accuracy of clinical tests for subacromial impingement syndrome: a systematic review and meta-analysis.

OBJECTIVE To examine the accuracy of clinical tests for diagnosing subacromial impingement syndrome (SIS). DATA SOURCES A systematic literature search was conducted in January 2011 to identify all studies that examined the diagnostic accuracy of clinical tests for SIS. The following search engines were used: Cochrane Library, EMBASE, Science Direct, and PubMed. STUDY SELECTION Two reviewers screened all articles. We included prospective or retrospective cohort studies that examined individuals with a painful shoulder, reported any clinical test for SIS, and used arthroscopy or open surgery as the reference standard. The search strategy yielded 1338 articles of which 1307 publications were excluded based on title/abstract. Sixteen of the remaining 31 articles were included. The PRISMA (preferred reporting items for systematic reviews and meta-analyses) guidelines were followed to conduct this review. DATA EXTRACTION The number of true positives, false positives, true negatives, and false negatives for each clinical test were extracted from relevant studies, and a 2×2 table was constructed. Studies were combined using a bivariate random-effects model. Heterogeneity was assessed using the variance of logit-transformed sensitivity and specificity. DATA SYNTHESIS Ten studies with 1684 patients are included in the meta-analysis. The Hawkins-Kennedy test, Neer's sign, and empty can test are shown to be more useful for ruling out rather than ruling in SIS, with greater pooled sensitivity estimates (range, .69-.78) than specificity (range, .57-.62). A negative Neer's sign reduces the probability of SIS from 45% to 14%. The drop arm test and lift-off test have higher pooled specificities (range, .92-.97) than sensitivities (range, .21-.42), indicating that they are more useful for ruling in SIS if the test is positive. CONCLUSIONS This systematic review quantifies the diagnostic accuracy of 5 clinical tests for SIS, in particular the lift-off test. Accurate diagnosis of SIS in clinical practice may serve to improve appropriate treatment and management of individuals with shoulder complaints.