Fate of mesenchymal stem cells transplanted to osteonecrosis of femoral head

The purpose of this study was to investigate the survival and differentiation status of MSCs transplanted to ONFH. Traumatic ONFH was surgically produced in skeletally mature mongrel dogs. Osteonecrosis was treated with either saline (control) or autologous mesenchymal stem cells (MSCs) transplantation after decompression. Green fluorescent protein (GFP) was used to track the transplanted MSCs, the differentiation of MSCs were evaluated by fluorescent double-labeling with GFP between osteocalcin or von Willebrand factor (vWF) at 2nd, 8th, and 12th week after the transplantation. It was demonstrated that GFP-positive cells were present in the necrotic area up to 12 weeks after the transplantation, their number increased from 15% at 2nd week to 38% at 12th week (p < 0.05). Neither osteocalcin nor vWF was detected by immunocytochemistry in GFP-labeled MSCs in vitro, but osteocalcin was immunohistochemically positive in 90% of the GFP-labeled MSCs in vivo, while vWF was still negative. The vWF expression was of no significant difference between the control group and MSCs-transplanted group. The percentages of trabeculae bone volume were 9.36% and 8.42% at 2nd week (p > 0.05), 22.82% and 14.72% at 8th week, and 31.08% and 20.66% at 12th week (p < 0.05) in MSCs-transplanted group and control group, respectively; new trabeculae bone in MSCs-transplanted group was significantly increased as compared to that of control group at 8th and 12th week. The results demonstrated that the transplanted MSCs could survive, proliferate, and differentiate into osteoblasts directly, which contributed to the accelerated repair process. The possible mechanism is site-dependant differentiation.

Treatment of osteonecrosis of the femoral head by percutaneous decompression and autologous bone marrow mononuclear cell infusion

OBJECTIVE

To evaluate the clinical efficacy and safety of the treatment of osteonecrosis of the femoral head by percutaneous decompression and autologous bone marrow mononuclear cell (BMCs) infusion.

METHODS

44 hips in 28 patients with avascular necrosis at early stage were treated by percutaneous multiple holes decompression followed by autologous BMCs infusion. Autologous BMCs were concentrated from bone marrow that was taken from the posterior iliac crest of the patient. Patients were followed up at least 2 years. The results were determined by the changes in the Harris hip score and the progression in the radiograghic stages.

RESULTS

No complications were observed after the operation. Before operation, there were stage I of femoral head necrosis in 8 hips, stage II in 15 hips, stage III in 14 hips, stage IV in 7 hips, and the postoperative stages at the most recent follow-up were stage O in 1 hip, stage I in 6 hips, stage II in 13 hips, stage III in 13 hips, stage IV in 7 hips, stage V in 4 hips. The mean preoperative Harris hip score was 58 (46-89), and improved to 86 (70-94) postoperatively. All the femoral head collapsed preoperatively showed that the necrotic size was at least more than 30%.

CONCLUSIONS

Percutaneous multiple holes decompression combined with autologous BMCs is a new way to treat avascular necrosis of the femoral head. The earlier the stage, the better the result. A randomized prospective study needed to compare with routine core decompression in the future.