Evaluation of spin in systematic reviews on the use of tendon transfer for massive irreparable rotator cuff tears

To identify, describe and account for the incidence of spin in systematic reviews and meta-analyses of tendon transfer for the treatment of massive, irreparable rotator cuff tears. The secondary objective was to characterize the studies in which spin was identified and to determine whether identifiable patterns exist among studies with spin. This study was conducted per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Each abstract was assessed for the presence of the 15 most common types of spin derived from a previously established methodology. General data that were extracted included study title, authors, publication year, journal, level of evidence, study design, funding source, reported adherence to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, preregistration of the study protocol, and methodologic quality per A Measurement Tool to Assess Systematic Reviews Version 2 (AMSTAR 2). The search yielded 53 articles, of which 13 were included in the final analysis. Articles were excluded if they were not published in a peer reviewed journal, not written in English, utilized cadaveric or nonhuman models, or lacked an abstract with accessible full text. 53.8% (7/13) of the included studies contained at least 1 type of spin in the abstract. Type 5 spin (“The conclusion claims beneficial effect of the experimental treatment despite a high risk of bias in primary studies”) was the most common, appearing in 23.1% (3/13) of included abstracts. Nine of the spin categories did not appear in any of the included abstracts. A lower AMSTAR 2 score was significantly associated with the presence of spin in the abstract (P