Introduction Subacromial pain syndrome (SAPS) lacks recognized diagnostic criteria. This could lead to important variations in concomitant shoulder diagnoses across populations. Knowledge of this could lead to an individualized approach, improving the overall handling of patients with SAPS. The aim was to investigate the prevalence of concomitant shoulder diagnoses in patients with SAPS.

Materials and Methods Patients were systematically screened for SAPS and for concomitant diagnoses using standardized diagnostic criteria: acromioclavicular osteoarthritis (OA), full-thickness rotator cuff tears, shoulder instability, long head biceps tendon pathology, labral lesions, and calcified tendinopathy. 17 standardized physical examination tests, radiographs, ultrasound, and MR were utilized. Tests were performed by experienced orthopedic specialists in accordance with predefined standardized protocols.

Results We systematically screened 3321 patients of whom 576 presented with signs and symptoms of SAPS. 168 of these were diagnosed with conflicting shoulder-related diagnoses (e.g., frozen shoulder or glenohumeral osteoarthritis). 408 were diagnosed with SAPS. Of these, 171 (42%) had at least one concomitant shoulder diagnosis, with acromioclavicular osteoarthritis, full-thickness rotator cuff tear and biceps tendon pathology being the most frequent. 55 of the 171 patients (32%) were diagnosed with multiple, concomitant diagnoses. In total, 22 different combinations of diagnoses were observed. Mean age was 56 years.

Conclusion Patients with SAPS often present with concomitant shoulder diagnoses. The clinical importance of this remains uncertain, but the high prevalence underpins the need for further investigations on the role of concomitant diagnoses in relation to prognosis and response to current treatment paradigms.