Abstract
Of the various conditions known to affect the periphery of the shoulder joint, least is known about periarthritis, or frozen shoulder. Although the illness was clinically identified many years ago, it continues to be known by an inaccurate name, its pathology remains mysterious and views regarding its therapy are divergent and confusing. The present study is concerned with evidence in support of the contention that the basic lesion in so-called periarthritis or frozen shoulder is bicipital tenosynovitis. Correlation of the clinical and pathologic observations to be herewith reported clarifies the mechanism which underlies the illness, explains its remarkable spontaneous cure and furnishes a sound basis on which conservative and surgical therapy may be planned. CHRONOLOGY The contributions of Duplay1 at the close of the nineteenth century represent the first effort to distinguish "humeroscapular periarthritis" from the vague general classification "arthritis." The disease that Duplay described corresponds clinically to what