The aim of the study is to evaluate a treatment of shoulder capsulitis that associates ARTHRO distension and intensive mobilisation at 2, 6, 12, 26 and 52 weeks. It is a bicentric 87-month (inclusion: 74 months; follow up: 13 months) observer blind randomised clinical trial using 2 groups in parallel. The number of patients to be included is 66. The treatment that is evaluated associates ARTHRO distension followed by mobilisation of the shoulder 6 hours per day during 5 days, and then sessions of physiotherapy for 4 weeks. The control intervention is one intra-articular injection of corticosteroids and physiotherapy. The primary outcome is SPADI, namely pain and disability, at 2 weeks.