Repair of segmental long-bone defects by stem cell concentrate augmented scaffolds: A clinical and positron emission tomography - Computed tomography analysis

Purpose: Treating segmental long-bone defects remains a major challenge. For defects >3 cm, segmental transport represents the gold standard, even though the method is time consuming and afflicted with several complications. The aim of this study was to evaluate healing of such defects after grafting an osteogenic scaffold previously seeded with stem cell concentrate. Methods: We evaluated five patients with segmental long-bone defects (3-14 cm) treated with bone marrow aspirate concentrates (BMAC) seeded onto a bovine xenogenous scaffold. The healing process was monitored by X-rays and positron emission tomography-computed tomography (PET-CT) three months after surgery. Results: Centrifugation led to a concentration of leukocytes by factor 8.1 ± 7.5. Full weight bearing was achieved 11.3 ± 5.0 weeks after surgery. PET analysis showed an increased influx of fluoride by factor 8.3 ± 6.4 compared with the contralateral side (p < 0.01). Bone density in the cortical area was 75 ± 16 % of the contralateral side (p < 0.03). The patient with the largest defect sustained an implant failure in the distal femur and finally accomplished therapy by segmental transport. He also had the lowest uptake of fluoride of the patient collective (2.2-fold increase). Conclusion: Stem cell concentrates can be an alternative to segmental bone transport. Further studies are needed to compare this method with autologous bone grafting and segmental transport.