Ixmyelocel-T Treatment of Patients With Osteonecrosis of the Femoral Head

Inclusion Criteria: * UPenn (Steinberg) classification of osteonecrosis, inclusive of Stages IIB and IIC. Diagnosis will be based on magnetic resonance imaging (MRI). * Modified index of necrotic extent \< 40 * Idiopathic and non-idiopathic osteonecrosis. * No infection in affected bones at the time of surgery. * Patient competent to give informed consent. * Normal organ and marrow function defined as: * Leukocytes ≥ 3000/µL; * Absolute neutrophil count ≥ 1500/µL; * Platelets ≥ 140,000/µL; * Serum AST (SGOT)/ALT (SGPT) \< 2.5 X institutional standard range; * Serum creatinine within normal limits, based on clinical laboratory normal range. * Female patients not pregnant or lactating. * Patients with a history of corticosteroids or on active therapy, will only be eligible for enrollment if corticosteroid use is suspended for 1 month prior and 6 months after cell therapy and surgery. * Patients who have been treated with oral bisphosphonates are eligible for the trial if treatment was stopped at least 6 months prior to enrollment. Exclusion Criteria: * Stages IA, IB, IC, IIA, IIIA or more severe femoral head osteonecrosis, primarily based on diagnosis by MRI. * Flattening of the femur head (UPenn Stage IV) or articular cartilage collapse at the time of core decompression surgery. * Septic arthritis; stress fracture, or non-osteonecrosis metabolic bone diseases (e.g., 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 * HIV, syphilis, positive at time of screening. * Active hepatitis B or hepatitis C infection at the time of screening * Known allergies to protein products (horse or bovine serum, or porcine trypsin). * Patients who will require continuous, systemic, high dose corticosteroid therapy (more than 7.5 mg/day) within 6 months after surgery. * Patients in active treatment for cancer or blood dyscrasia, or have received chemotherapy, radiotherapy or immunotherapy in the past 2 years. * Immunodeficiency diseases. * Participation in another clinical study in the past 30 days or concurrent participation in another clinical trial. * History of regular alcohol consumption exceeding 2 drinks/day (1 drink = 5 oz \[150 mL\] of wine or 12 oz \[360 mL\] of beer or 1.5 oz \[45 mL\] of hard liquor) within 6 months of screening and/or history of illicit drug use. * MRI-incompatible internal devices (pacemakers, aneurysm clips, etc) * Body mass index (BMI) of 40 Kg/m2 or greater * Patients unable to tolerate general anesthesia defined as an American Society of Anesthesiologists (ASA) criteria of \> 2 * 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 anti-angiogenesis treatment * Traumatic osteonecrosis