The purpose is to assess the safety and feasibility of cellular therapy derived from bone marrow, to help bone healing in patients with avascular necrosis of the hip.

To assess the safety and feasibility of an in situ single injection of a high dose of autologous bone marrow-derived, in vitro expanded Mesenchymal stem cells, and its contribution to the resolution of the early stages of avascular osteonecrosis of the femoral head.

Inclusion Criteria:

Age 18 to 65, both sexes

• Early avascular necrosis of the fem oral head (MRI diagnosis): Ficat and Arlet 0, 1, or 2 (Steinberg stages 0, I, IIA, IIB, or IIC)
• Sym ptom atic osteonecrosis with less than 6 months of evolution
• Able to provide informed consent, and signed informed consent
• Medical health care coverage

Exclusion Criteria:

• Pregnancy, breast feeding women and women who are of childbearing age and not practicing adequate birth control.
• Participation in another therapeutic trial in the previous 3 m onths
• Stages 3 or m ore (Ficat and Arlet) or III or m ore (Steinberg) of severe fem oral head osteonecrosis,primarily based on diagnosis by im aging (X-Rays, MRI).
• Flattening or collapse of the fem oral head (Steinberg stage IV) or articular cartilage collapse at the time of core decompression surgery.
• Septic arthritis.
• Stress fracture.
• Non-osteonecrosis metabolic bone diseases (particularly Paget's disease of bone, osteogenesis imperfecta, primary hyperparathyroidism , fibrous dysplasia monostotic, polyostotic McCune-Albright syndrome] and osteopetrosis).
• Any active bisphosphonate treatment or any history of intravenous (IV) treatment.
• History of prior or concurrent diagnosis of HIV-, Hepatitis-B- or Hepatitis-C-infection
• Active hepatitis B or hepatitis C infection at the time of screening.
• Known allergies to products involved in the production process of MSC.
• History of neoplasia or current neoplasia in any organ.
• Corticoid or immunosuppressive therapy more than one week in the two months prior to study inclusion
• Patients who will require continuous, systemic, high dose corticosteroid therapy (more than 7.5 m g/day) within 6 months after surgery.
• Patients who are in active treatment for cancer or blood dyscrasia, or have received chemotherapy, radiotherapy or immunotherapy in the past 2 years.
• History of regular alcohol consumption exceeding 2 drinks/day within 6 months of screening and/or history of illicit drug use.
• Serum AST (SGO T)/ALT (SGPT) > 2.5 X (institutional standard range).
• MRI-incompatible internal devices (pacemakers, aneurysm clips, etc).
• Body mass index (BMI) of 40 kg/m ² or greater.
• Patients unable to tolerate general anesthesia defined as an American Society of Anesthesiologists (ASA) criteria of > 2.
• Insulin dependent diabetes
• Patients with poorly controlled diabetes mellitus (HbA1C > 8%), or with peripheral neuropathy, or known concomitant vascular problems.
• Patients receiving treatment with hematopoietic growth factors or anti-vasculogenesis or antiangiogenesis treatment.
• Traumatic osteonecrosis.
• Adult in the care of a guardian (Subject legally protected)
• Im possibility to meet at the appointments for the clinical follow up.