This trial is investigating the safety and effectiveness using the patient's own fat stem cells in the treatment of avascular necrosis of the femoral head. The trial is being conducted by the SMG-SNU Boramae Medical Center in Seoul, in conjunction with RNL Bio Co Ltd. Participants will have stem cells obtained from their own fat transplanted into the femoral head. Participants will be monitored for complications and changes in their clinical condition. The trial seeks to enrol 15 participants with between May 2012 and July 2014.