Introduction There is no recognised terminology, nor diagnostic criteria, for patients with subacromial pain syndrome (SAPS). This is likely to cause heterogeneity across patient populations. This could be a driver of misconceptions and misinterpretations of scientific results. We aimed to map the literature regarding terminology and diagnostic criteria used in studies investigating SAPS.

Materials and methods Electronic databases were searched from inception to June 2020. Original peer-reviewed studies investigating SAPS (also known as subacromial impingement or rotator cuff tendinopathy/impingement/syndrome) were eligible for inclusion. Studies containing secondary analyses, reviews, pilot studies and studies with less than 10 participants were excluded.

Results 11 056 records were identified. 902 were retrieved for full-text screening. 535 were included. 27 unique terms were identified. Mechanistic terms containing ‘impingement’ are used less than before, while SAPS is used increasingly. For diagnoses, combinations of Hawkin’s, Neer’s, Jobe’s, painful arc, injection test and isometric shoulder strength tests were the most often used, though this varied considerably across studies. 146 different test combinations were identified. 9% of the studies included patients with full-thickness supraspinatus tears and 46% did not.

Conclusion The terminology varied considerably across studies and time. The diagnostic criteria were often based on a cluster of physical examination tests. Imaging was primarily used to exclude other pathologies but was not used consistently. Patients with full-thickness supraspinatus tears were most often excluded. In summary, studies investigating SAPS are heterogeneous to an extent that makes it difficult, and often impossible, to compare studies.