Abstract
Introduction
Since 2005, we have performed implantation of bone marrow-derived mononuclear cells for osteonecrosis of the femoral head in order to improve vascularization and bone repair. This study focused on early bone repair of osteonecrosis of the femoral head after transplantation of bone marrow-derived mononuclear cells (BMMNC).
Patients and Methods
Twenty-two patients (30 joints) who had bilateral osteonecrosis followed for more than 2 years after BMMNC implantation were evaluated. Eight women and 14 men were included. Their mean age at surgery was 41 years (range, 18 to 64 years) and the mean follow-up period was 31 months. Pre-operative stage according to the ARCO classification was Stage 2 in 25 joints and Stage 3 in 5 joints. The mean volume ratio of osteonecrosis was 21%. For preparing BMMNC, about 700ml of bone marrow was aspirated from the ilium and centrifuged using a Spectra cell separator (Gambro). The BMMNC were seeded to interconnected porous calcium hydroxyapatite (IP-CHA) and implanted to the osteonecrotic lesion. As a control, cell-free IP-CHA was implanted for 8 patients (9 joints). A woman and 7 men were included. The mean age at surgery was 49 years (range, 28 to 73 years) and the mean follow-up period was 37 months. Preoperative stage was stage 2 in all patients. The mean volume ratio of osteonecrosis was 22%. At post-operative evaluations; progression of collapse, consolidation at reactive zone, post-operative course of volume rate of osteonecrosis, and bone absorption at osteonecrosis was assessed.
Results
Shrinkage of osteonecrosis has been observed subsequent to bone consolidation at the transitional zone which progressed from 3 to 6 months post-operatively in the BMMNC-seeded group. Progression of collapse more than 2 mm was detected in 4 joints (13%), and hip arthroplasty was performed in 1 joint (3%). Consolidation at the reactive zone was detected in 28 joints (93%) and the volume rate of osteonecrosis significantly decreased by 12 months after surgery. Bone resorption at the osteonecrotic lesion was observed in 14 joints (47%). Meanwhile, subtle bone consolidation was detected after 12 months post-operatively in the control group. Progression of collapse was observed in 6 joints (67%) and further surgical treatments were needed in 3 joints (33%).
Conclusion
This study found that BMMNC was beneficial to osteonecrosis of the femoral head from the viewpoint of prevention of collapse.
