Autologous mesenchymal stem cell implantation in the management of osteonecrosis of the femoral head

Background: The aim of this study was to evaluate the results of implantation of mesenchymal stem cells (MSCs) as treatment for early-stage osteonecrosis of the femoral head (ONFH). Methods: A retrospective study was conducted of patients with early-stage ONFH treated by core decompression alone (CD group) or core decompression with autologous MSC implantation (MSC group) between July 2008 and June 2010. MSCs were injected into the femoral head through the core decompression channel. Clinical assessment included a visual analog scale (VAS) score and the Harris Hip Score (HHS). Radiographically, we assessed femoral head collapse, the size of the osteonecrotic area, and progression. Results: The mean VAS score and HHS improved in both groups from preoperative values. The MSC group experienced better relief of articular pain than the CD group, although this did not reach statistical significance. At follow-up, four of 42 patients in the CD group progressed from stage II ONFH to stage III, whereas only one of 44 patients in the MSC group progressed from stage II to stage III. Neither flattening of the femoral head nor hip joint narrowing was encountered in either group. Conclusions: MSC implantation combined with core decompression relieved articular pain and prevented progression of osteonecrosis in almost all patients. Hence, MSC injection may be a method for preventing femoral head collapse during early ONFH.