Introduction

In recently, Reverse shoulder arthroplasty (RSA) in patients with irreparable rotator cuff tear has been worldwidely performed. Many studies on RSA reported a good improvement in flexion of the sholulder, however, no improvement in external rotation (ER)and internal rotation motion (IR). Additionally, RSA has some risks to perform especially in younger patients, because high rates of complications such as deltoid stretching and loosening, infection, neurologic injury, dislocation, acromial fracture, and breakage of the prosthesis after long-term use were reported. Favard et al noted a 72% survival with a Constant-Murley score of <30 at 10 years with a marked break occurring at 8 years. Boileau et al noted caution is required, as such patients are often younger, and informed consent must obviously cover the high complication rate in this group, as well as the unknown longer-term outcome. Its use should be limited to elderly patients, arguably those aged over 70 years, with poor function and severe pain related to cuff deficiency. We developed a novel strategy in 2001, in which we used the humeral head to close the cuff defect and move the center of rotation medially and distally to increase the lever arm of the deltoid muscle.