This randomized clinical trial aims to determine if cells from a patient's own adipose tissue is safe and capable of helping regenerate the femoral head in patients with osteonecrosis. The standard of care is known as hip decompression which simply removes dead tissue from the femoral head and creates a new cavity to be filled in by healthy bone. This trial will use hip decompression plus saline injection in one hip and hip decompression supplemented with adipose derived regenerative cells in patients with osteonecrosis in both of their hips.