robbin. she's 54 years old. after decades of wear and tear on her knees, her right knee caused her a tremendous amount of pain. >> i go to work, but it's just hurting all the time. >> you can see on the right knee, she has no space left between the femur and tibia. >> it's the two bones surrounding the knee. she's rolling into dr. o.'s operating room in atlanta. before we get started, i want to give you a tour of what happens inside the operating room. you look at a scene like this. this person usually to the surgeon's right is a scrub nurse. they hand sterile instruments to the surgeon. dr. o. is standing there, operating. a physicians assistant stand zs