Conservative treatment is advocated for proximal humeral fracture without displacement. When fracture displacement is identified, it is not always possible to change the treatment plan. In essence, once it develops, it is difficult to treat. Nonunion of a proximal humeral fracture can produce severe shoulder dysfunction. We have explored treating the nonunion of proximal humeral fracture with reverse shoulder arthroplasty (RSA).

 A 68-year-old man had a history of a fall and subsequent right shoulder pain when he was in his fifties. His pain and restriction of shoulder motion continued for about 15 years in spite of conservative treatment. At many previous hospitals, he had been given a diagnosis of nonunion of the proximal humeral surgical neck due to a prior suspected fracture. When he consulted us, his range of motion in the right shoulder was restricted to 70° active flexion, 90° passive flexion, 70° active abduction, and 90° passive abduction. He was operated with RSA by using a superior approach in order to see around the tuberosity and rotator cuffs. Postoperatively, the patient was monitored for four weeks with the application of a simple shoulder sling to avoid glenohumeral dislocation. Active-assisted rehabilitation of the shoulder commenced on the next day after surgery. The Japan Orthopaedic Assoication score, Constant score, shoulder anterior flexion (active 150°), and abduction (active 150°) were significantly improved two years after RSA, but tuberosity healing was not adequate and external rotation has slightly degenerated.

 Whereas RSA for a fracture is technically easier to perform than a standard RSA, over tensioning can lead to postoperative problems including reflex sympathetic dystrophy and brachial plexopathy and this should be avoided. As is the case with fracture, RSA for nonunion of proximal humeral fractures can relieve a patient's pain and improve their quality of life. Although anatomic tuberosity healing has been considered less important when RSA is performed, in our case, the function of external rotation was not improved. In order to encourage tuberosity healing, we need to improve intraoperative methods including a change of the implant. Nevertheless, we consider that RSA is a viable treatment option for nonunion of a proximal humeral fracture.