Cryopreserved bone allografts(CBA) are susceptible to infection, nonunion, and late stress fracture. Although surgical revascularization by intramedullary implantation of an arteriovenous bundle (AV bundle) generates a neoangiogenic blood supply, there is potential for vascular ingrowth-mediated bone resorption to weaken the graft. For this reason, we have evaluated changes in CBA mechanical properties of structural tibial allografts with and without surgically induced angiogenesis. Cryopreserved tibia bone allografts were transplanted to reconstruct a 3.5 cm segmental tibial defect in 16 Yucatan mini pigs. Surgical revascularization was performed in half by implantation of a cranial tibial AV bundle, (revascularization group). A control group of identical size had a ligated AV bundle implanted, (ligated group). At 20 weeks micro-computed tomography (CT) measured bone mineral density (BMD) as well as bone union. Reference point indentation (RPI) compared cortex material properties, and axial compression determined the allotransplant compressive modulus. Seven of eight tibiae in the angiogenesis group were healed at both junction points at 20 weeks. Only four of eight tibiae healed in the ligated control group. There was no significant difference between the revascularization and ligated control groups in BMD and axial compression test. Similarly, RPI parameters were statistically equal. In paired comparisons with contralateral tibias, however, some RPI values were significantly worse in the ligated control group tibiae. This study demonstrates no adverse effect of surgical angiogenesis on cryopreserved structural bone allograft biomechanical properties in a large animal orthotopic segmental tibial defect model. These data suggest the potential value of surgical angiogenesis in clinical limb-sparing reconstructive surgery.

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手术血运重建对猪胫骨模型中冷冻保存的同种异体骨力学性能的影响

冷冻保存的同种异体骨移植物 (CBA) 易受感染、骨不连和晚期应力性骨折的影响。尽管通过髓内植入动静脉束（AV 束）进行外科血运重建会产生新血管生成血液供应，但血管向内生长介导的骨吸收可能会削弱移植物。出于这个原因，我们评估了在有和没有手术诱导的血管生成的情况下，结构性胫骨同种异体移植物的 CBA 机械特性的变化。移植冷冻保存的胫骨同种异体骨移植物以重建 16 只尤卡坦小型猪的 3.5 厘米节段性胫骨缺损。通过植入颅胫骨 AV 束（血运重建组）对一半进行手术血运重建。相同大小的对照组植入了结扎的 AV 束（结扎组）。在 20 周时，微型计算机断层扫描 (CT) 测量了骨矿物质密度 (BMD) 以及骨愈合。参考点压痕 (RPI) 比较了皮质材料的特性，轴向压缩确定了同种异体移植物的压缩模量。血管生成组的 8 根胫骨中有 7 根在 20 周时在两个连接点处愈合。在结扎对照组中，八根胫骨中只有四根愈合。血运重建组和结扎对照组在骨密度和轴压试验中无显着差异。同样，RPI 参数在统计上是相等的。然而，在与对侧胫骨的配对比较中，结扎对照组胫骨的一些 RPI 值明显更差。本研究表明，在大型动物原位节段性胫骨缺损模型中，手术血管生成对冷冻保存的同种异体结构骨生物力学特性没有不利影响。这些数据表明外科血管生成在临床保肢重建手术中的潜在价值。