Abstract

Context: Shoulder injury is common even in asymptomatic athletes, but the estimated frequency varies between studies. Objective: To conduct a systematic review with meta-analysis to evaluate the frequency of shoulder pathologies seen on MRI in asymptomatic athletes. Methods: This systemic review was conducted in accordance to the preferred reporting items for systemic reviews and meta-analysis guidelines. Data sources: We searched three electronic databases (PubMed/MEDLINE, Web of Science, Embase) for studies reporting on frequency of asymptomatic shoulder pathology on MRI using the keywords “shoulder”, “asymptomatic”, “imaging” and “athlete” up until February 10, 2023. Study design: Meta-analysis of proportions. Level of evidence: 3 Data extraction: Data was extracted by 2 authors. Risk of bias assessment was conducted using a 12-item checklist adapted for frequency studies. Results: 19 studies with a total of 569 shoulders that underwent MRI analysis were included. The primary outcome of the study was the pooled frequency of shoulder pathology (rotator cuff, biceps, subacromial bursa, labrum, Acromioclavicular (AC) joint, humerus) on MRI. The overall pooled frequency estimate of shoulder pathology is as listed: Rotator cuff pathology at 46% (CI 26% to 67%), biceps tendon pathology at 5% (CI 1% to 19%), subacromial pathology at 53% (CI 29% to 76%), labral pathology at 29% (CI 14% to 52%), AC joint pathology at 28% (CI 14% to 48%), and humeral head pathology at 46% (CI 31% to 62%). From our random effects model subgroup analysis, athletes participating in overhead sport and elite athletes demonstrated higher frequency of shoulder pathology overall. Conclusion: Pooled summary estimates of the frequency of shoulder pathology on MRI in asymptomatic athletes ranged from 5.0% to 55.7%, with significantly higher frequency seen in higher level athletes and overhead sports. This confirms the hypothesis that there is a high frequency of asymptomatic shoulder pathology in asymptomatic athletes likely related to wear and tear on the shoulder. Registration: INPLASY (INPLASY202320108).

Keywords:Magnetic resonance; Imaging; Asymptomatic athletes; Frequency; Shoulder pathologies; Acromioclavicular; Subacromial bursa, Labrum; Swimming injuries