Beyond the capsule: an integrated perspective on the wide world of frozen shoulder. A collaborative viewpoint.

Abstract

Background: Frozen Shoulder (FS) is a highly disabling glenohumeral condition marked by severe pain and restricted active and passive motion, typically without significant radiological changes. While conventionally viewed as a self-limiting and idiopathic disorder, recovery is often incomplete, suggesting that peripheral-only interventions are insufficient.

Objective: This manuscript reviews the contemporary understanding of FS etiopathogenesis, clarifying the underlying pain processing mechanisms, metabolic patterns, and psychological domains. Evidence about diagnostic tests and imaging for FS, and updated treatment strategies were also discussed.

Key findings: The latest evidence suggests FS is the musculoskeletal manifestation of systemic metabolic, inflammatory, and neuroendocrine dysregulation. Pain mechanisms extend beyond the periphery, showing links to sensitization and possible central involvement, though further clarity is needed. Moreover, FS significantly impacts mood, beliefs, and social well-being. Imaging remains a tool for diagnosis and differential ruling, and treatment should be "tailorized" from biopsychosocial perspective. Individualization involves the understanding of the individual's personal history, clinical characteristics, context, and goals in combination with tissue irritability.

Conclusion: Clinicians must move beyond solely addressing FS as a "local" pathology. Modern research indicates that FS is a complex pathology involving an inflammatory phase followed by a fibrotic shift, fueled by metabolic, inflammatory, neuroendocrine, and psychological factors.