Arthroscopic appearance of frozen shoulder.

Patients (n = 150) were referred to a shoulder clinic with a diagnosis of "frozen shoulder" and the suggestion that they be submitted to manipulation. All patients were further investigated using local anesthetic blocks, routine radiography, and, often, computed tomographic scanning and arthrograms. Subsequently, it appeared that only 37 patients qualified for the diagnosis of "primary" frozen shoulder. The others had a "secondary" frozen shoulder from some other painful cause, such as a rotator cuff tear or impingement. The 37 patients were arthroscoped and then manipulated while under general anesthesia. Patients were told that both irrigation and local injection of the joint would have an additional beneficial therapeutic effect in the recovery phase, and they gave prior consent to the procedures. There were no complications. Pain relief was striking. The arthroscopic appearance was uniform: a patchy vascular reaction around the biceps, and the opening into the subscapularis bursa. The capacity of the joint was reduced. In no patient was the infraglenoid recess obliterated, and no adhesions were seen. Such findings at routine shoulder arthroscopy should alert the surgeon to a diagnosis of frozen shoulder if the clinical presentation has been subtle. The findings raise questions about the previous pathological interpretation of this condition.