Pathophysiology of Frozen shoulders: Histology and laboratory tests

The main pathology of frozen shoulder used to be considered as fibrosis and inflammation. Our recent study has demonstrated that chondrogenesis is also characteristic to idiopathic frozen shoulders. The cell density was significantly higher and the capsular tissue was significantly stiffer in frozen shoulders compared with shoulders with rotator cuff tears. Staining intensity of alcian blue was significantly stronger in frozen shoulders. Gene expressions related to fibrosis, inflammation, and chondrogenesis were significantly higher in frozen shoulders. In addition to fibrosis and inflammation, chondrogenesis is likely to have a critical role in the pathogenesis of idiopathic frozen shoulders. There is no specific blood test for frozen shoulder.