In stage 3 Osteonecrosis (ON) of the femoral head, a beneficial effect of bone marrow grafting was reported with a reduction of the functional evolution and the necessity of a total prosthesis placement in a non-controlled retrospective trial. Based on this experience, the investigators would like to start a randomized controlled double blind study on the effect of autologous implantation of autologous bone marrow cells into the necrotic lesion of stage 3 ON of the femoral head.

Inclusion Criteria:

1. patients who have a non traumatic ON of the femoral head
2. Stage 3 ON (subchondral fracture).
3. Age > 18 years
4. Be able and willing to participate in the study

Exclusion Criteria:

1. evidence of malignant disorder in the past five years
2. Patient unable to undergo a MRI.
3. Patient who is positive for an HIV, hepatitis B or C infection.