There are several types of osteotomies described in the literature (e.g., rotational, angulation). No matter what type they all have the same goal, to preserve the femoral head by altering the pattern of stress transfer. A varus osteotomy attempts to shift the most involved portion of the head medially. A valgus osteotomy attempts to shift the superolateral lesion more lateral. Often varus and valgus osteotomies are performed in conjunction with a flexion osteotomy. Rotational osteotomies by design attempt to shift the diseased head medially, inferiorly and posteriorly.
For all of the osteotomies, there have been excellent short-term results. For angulation osteotomies with small to medium size lesions initial results are good to excellent in 60-75% of patients at three to five years. Rotational osteotomies have had anywhere from 20-100% success depending on how much intact area of femoral head was the weight bearing surface after transposition. The better results correlating with greater intact weight bearing surface areas.