The aim of this study was to investigate about the natural course of idiopathic frozen shoulder and the efficacy of conservative treatment.

Twenty-five cases of unilateral frozen shoulder (study group) treated conservatively by intra-articular steroid injection and staged passive stretching were prospectively followed for average 9.1 months, the outcome was assessed in terms of motion range and the function score derived from patients' self-evaluation, and timing of improvement was searched. Compared with study group, 20 patients (control group) , who were diagnosed as idiopathic frozen shoulder but didn't undertake specific treatment, were checked at average 40 months.

Eighteen cases (72%) of the study group had residual symptom, which was mild in most cases. Range of motion less than 80% of normal side was noted in 2 cases. Intra-articular steroid injection was effective for pain relief in 75%. In the control group, one case showed decreased motion and 2 case had mild pain. Comparing with the control group, the study group was improved significantly & statistically faster.

It is construed that the long term result of idiopathic frozen shoulder is excellent and the combined effect of steroid injection and stretching shortens the duration of disease. Operative treatment for idiopathic frozen shoulder, if indicated, needs to be decided after long term follow-up.