Background: Aseptic nontraumatic osteonecrosis of the femoral head
is a disorder that can lead to femoral head collapse and the need for total
hip replacement. Since osteonecrosis may be a disease of mesenchymal cells or
bone cells, the possibility has been raised that bone marrow containing
osteogenic precursors implanted into a necrotic lesion of the femoral head may
be of benefit in the treatment of this condition. For this reason, we studied
the implantation of autologous bone-marrow mononuclear cells in a necrotic
lesion of the femoral head to determine the effect on the clinical symptoms
and the stage and volume of osteonecrosis.
Methods: We studied thirteen patients (eighteen hips) with stage-I
or II osteonecrosis of the femoral head, according to the system of the
Association Research Circulation Osseous. The hips were allocated to a program
of either core decompression (the control group) or core decompression and
implantation of autologous bone-marrow mononuclear cells (the
bone-marrow-graft group). Both patients and assessors were blind with respect
to treatment-group assignment. The primary outcomes studied were safety,
clinical symptoms, and disease progression.
Results: After twenty-four months, there was a significant reduction
in pain (p = 0.021) and in joint symptoms measured with the Lequesne index (p
= 0.001) and the WOMAC index (p = 0.013) within the bone-marrow-graft group.
At twenty-four months, five of the eight hips in the control group had
deteriorated to stage III, whereas only one of the ten hips in the
bone-marrow-graft group had progressed to this stage. Survival analysis showed
a significant difference in the time to collapse between the two groups (p =
0.016). Implantation of bone-marrow mononuclear cells was associated with only
minor side effects.
Conclusions: Implantation of autologous bone-marrow mononuclear
cells appears to be a safe and effective treatment for early stages of
osteonecrosis of the femoral head. Although the findings of this study are
promising, their interpretation is limited because of the small number of
patients and the short duration of follow-up. Further study is needed to
confirm the results.
Level of Evidence: Therapeutic study, Level II-1
(prospective cohort study). See Instructions to Authors for a complete
description of levels of evidence.