Comparison of Large Segmental Bone Defect Healing after Transplantation of Autogenous Cancellous Bone Graft and after Implantation of HAP-Collagen Scaffold Combined with Mesenchymal Stem Cells
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| Year of publication | 2012 |
| Type | Conference abstract |
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| Description | In clinical practice in children, the need of surgical management of large bone defects might be relatively frequently encountered, either due to loss integrity of the bone column in comminuted fractures, or after ostectomy in cases of bone tumour resection. This experimental animal model study evaluates radiographic healing of segmental femoral defects in miniature pigs based on determination of the callus: cortex ratio at 16 weeks after ostectomy. Materials and Methods In the miniature pig model (n = 18) iatrogenic segmental bone defect (ostectomy) was created in the centre of diaphysis of the left femur. Osteotomized bone was stabilized using a five-hole 4.5 mm titanium LCP (Synthes Switzerland) and four 4.5 mm titanium locking screws inserted bicortically, leaving central plate hole (at the level of the segmental bone defect) empty. In animals of group A (n = 6), the defect was filled with autogenous cancellous bone graft harvested from tuberculum majus humeri of the left humerus. In animals of group S (n = 6), the segmental bone defect was filled with newly developed cylindrical (20 mm x 15 mm) mechanically self-supporting resorbable nanocomposite scaffold from hydroxyapatite (HAP) and 0.5% collagen (1:1). In animals of group S + MSCs (n = 6), the iatrogenic femoral defect was filled with the same HAP and 0.5% collagen (1:1) scaffold seeded with mesenchymal stem cells (MSCs). Results and Discussion The size of the formed callus was significantly larger (p < 0.05) in animals after transplantation of an autogenous cancellous bone graft (group A, callus : cortex ratio of 1.77 +/- 0.33) compared to animals after implantation of the HAP and 0.5% collagen (1:1) (group S, callus : cortex ratio of 1.08 +/- 0.13), or in animals after implantation of the scaffold seeded with MSCs (group S + MSCs, callus: cortex ratio of 1.15 +/- 0.18). No significant difference was found in the size of callus between animals of group S and group S + MSCs. Unlike a scaffold in the shape of the original bone column, a freely placed autogenous cancellous bone graft may allow the newly formed tissue to spread more to the periphery of the ostectomy defect. |