Stem cell therapy for osteonecrosis of the femoral head.

Aseptic non-traumatic osteonecrosis of the femoral head is a painful disorder of the hip that can lead to femoral head collapse and the need for total hip replacement. As osteonecrosis may be a disease of mesenchymal cells or bone cells, the possibility has been raised that bone marrow containing osteogenic precursors implanted into the necrotic lesion could be of benefit in this condition. Indeed, bone marrow contains adult stem cells, such as haematopoietic stem cells, mesenchymal stem cells and multipotent stem cells, that might have osteogenic properties. The efficacy of bone marrow implantation into the osteonecrotic zone was studied in two prospective trials. This treatment avoided the progression of the disease to the stage of the subchondral fracture (stage III) and reduced the need for total hip replacement. The mechanisms involved might include improved osteogenesis and angiogenesis. This new therapeutic approach should modify the treatment of early-stage osteonecrosis of the femoral head.