An 79-year-old male presents with longstanding left shoulder pain and difficulty with raising his arm over his head. His exam shows wasting of the deltoid and obvious scapular dysrhythmia on the left side. He lacks the ability to do any forward flexion or external rotation in his left shoulder. He can internally rotate without difficulty. His radiograph and MRI images are seen in figures A and B respectively. He wants to know if he is a candidate for a reverse shoulder arthroplasty (RSA). Which of the following answer choices is the MOST appropriate response?