Ortho Dx: What is the best treatment for this shoulder pain?

A 62-year-old woman presents with 3 months of left shoulder pain. She had a displaced proximal humerus fracture on the left a few years ago that was treated nonoperatively and had recovered well until recently. Anteroposterior X-ray (Figure 1) and coronal MRI image (Figure 2) of the left shoulder show osteonecrosis of the humeral head with ...