Abstract
OBJECTIVE: To review the research progress of pathological changes of glenohumeral capsule in patients with recurrent shoulder anterior dislocation (RSAD). METHODS: The literature on shoulder capsules, both domestic and international, was reviewed. The anatomy, histology, and molecular biology characteristics of the glenohumeral capsule in RSAD patients were summarized. RESULTS: Anatomically, the glenohumeral capsule is composed of four distinct parts: the upper, lower, anterior, and posterior sections. The thickness of these sections is uneven, and the stability of the capsule is further enhanced by the presence of the glenohumeral and coracohumeral ligaments. Histologically, the capsule tissue undergoes adaptive changes following RSAD, which improve its ability to withstand stretching and deformation. In the realm of molecular biology, genes associated with the regulation of structure formation, function, and extracellular matrix homeostasis of the shoulder capsule's collagen fibers exhibit varying degrees of expression changes. Specifically, the up-regulation of transforming growth factor β (1) (TGF-β (1)), TGF-β receptor 1, lysyl oxidase, and procollagen-lysine, 2-oxoglutarate 5-dioxygenase 1 facilitates the repair of the joint capsule, thereby contributing to the maintenance of shoulder joint stability. Conversely, the up-regulation of collagen type Ⅰ alpha 1 (COL1A1), COL3A1, and COL5A1 is linked to the recurrence of shoulder anterior dislocation, as these changes reflect the joint capsule's response to dislocation. Additionally, the expressions of tenascin C and fibronectin 1 may play a role in the pathological processes occurring during the early stages of RSAD. CONCLUSION: Glenohumeral capsular laxity is both a consequence of RSAD and a significant factor contributing to its recurrence. While numerous studies have documented alterations in the shoulder capsule following RSAD, further research is necessary to confirm the specific pathological anatomy, histological, and molecular biological changes involved.