Osteoarthritis (OA) is the world's most common joint disease and there is currently no cure. Glenohumeral osteoarthritis (GHOA) accounts for an estimated 5%-17% of patients with shoulder complaints. The etiology of GHOA is multifactorial, and we review the various non-specific and specific risk factors and further sub-classify them into local and systemic factors.
Data for this review article were identified by searches of MEDLINE, PubMed, and references from relevant articles using search terms such as "glenohumeral," "osteoarthritis," "epidemiology," "etiology," "imaging," and "pathophysiology." Only articles published in English, German, and Finnish between 1957 and 2017 were included.
The prevalence of radiological shoulder OA has been estimated to be as high as 16%-20% in the middle-aged and elderly population, but the concordance between structural findings and symptoms seems to be weak, as many of these individuals are asymptomatic. The vast majority of GHOA is related to non-specific factors, namely advancing age, while specific risk factors are commonly found in young patients. Diagnosis of GHOA is made when typical clinical features and defined radiological findings overlap in an individual.
Conclusion: Ultimately the determinants of shoulder pain in GHOA remain incompletely understood. Improved understanding of the etiology and diagnosis of GHOA will enable clinicians to better determine which patients will benefit from different treatment modalities, as well as provide new avenues to potential treatments.