The effect of bone marrow mononuclear cells on vascularization and bone regeneration in steroid-induced osteonecrosis of the femoral head

Objective: We examined whether implantation of autologous bone marrow mononuclear cells (BM-MNC) can augment neovascularization and bone regeneration in steroid-induced osteonecrosis of the femoral head. Methods: Sixty-five 28-week-old male New Zealand white rabbits were divided into group I (left untreated, N=20), group II (core decompression, N=20) and group III (core decompression + autologous bone marrow cells implantation, N=25) after receiving an established inductive protocol for inducing steroid-associated ON. Four weeks later, these rabbits were euthanized, bilateral femora were dissected for micro-CT-based microangiography to assess vascularization, and then the osteonecrotic changes and repair processes were examined histopathologically. Results: Quantitative analysis showed that new vessel formation in group III was significantly greater compared with other groups at 4 weeks after treatment. Penetrating capillary vessels number vessels number in group III (44.5 +/- 5.11) was significantly larger than that of group II (11.4 +/- 2.46) and group I (3.10 +/- 0.33) (p < 0.01). The histologic and histomorphometric analysis revealed that the new bone volume was significantly higher in the group III than in the group I and 11, 4 weeks after treatment. Conclusion: In this animal model, a combination of bone marrow mononuclear cells and core decompression enhance the neovascularization and the osteoinductive ability, resulting in bone regeneration. These findings confirm the preliminary clinical results obtained in humans that the implantation of bone marrow mononuclear cells is an effective and feasible method for treating early osteonecrosis. (C) 2009 Societe francaise de rhumatologie. Published by Elsevier Masson SAS. All rights reserved.