Only your doctor can tell you what type of surgery is being considered for your daughter, however, there are a few different types of treatments that are done through surgery.
Traditionally, most doctors who operate on this problem do what is called a debriding, or removing dead tissue. This clears the area and removes any loose bits that may be present. Another procedure is called a microfracture. To do this procedure, the doctor makes a small incision and uses a tiny drill to make several very small holes in the bone right next to the problem area. When the holes are drilled, the bone marrow seeps out and makes new tissue, healing the lesion.