Background: Idiopathic frozen shoulder (IFS) is able to be classified into the two types according to 3D-CT: the rib elevation type (E type) and the rib depression type (D type). The purpose of this study was to clarify clinical characteristics and pathophysiology of each type and establish the classification according to the clinical findings.
Methods: We examined 56 shoulders in 54 patients (20 males, 34 females, mean age 56.5 years old) with IFS, and classified them into the E type and the D type according to 3D-CT. Comparative assessments were as following: sex, age, visual analog scale (VAS), range of motion (ROM) of the shoulder, tenderness in pectoralis major, pain of passive motion at the sternoclavicular and sternocostal joints, passive motions of the scapula, tenderness of subscapularis (SSC), teres minor (TM) and infraspinatus (ISP).
Results: E type consisted of 17 shoulders in16 patients and D type consisted of 39 shoulders in 38 patients. The E type showed more improvement of VAS and milder contracture of shoulder joint. Tenderness in the pectoralis major, pain of passive motion at the sternoclavicular and sternocostal joints were identified in the only E type. Scapular passive motions in D type were restricted in depression, downward rotation, adduction, and posterior tilting, whereas, no or slight restriction was identified in E type. Induration at the SSC and TM was strongly palpated in D type.
Conclusion: Two kinds of pathophysiology in IFS were elucidated from this study. We should perform physical treatment for IFS according to each pathophysiology.
