OSTEOCONDUCTIVE SCAFFOLD FOR CORTICAL BONE ALLOGRAFTS

先前的研究表明，通过部分脱矿和激光穿孔对皮质骨同种异体移植物进行修饰可以增强其与宿主骨的结合。然而，这些研究也表明，植入通常先于骨吸收，这可能导致过早的机械故障。本研究的目的是研究是否可以通过涂覆富马酸聚丙烯（PPF）的生物可吸收聚合物泡沫来促进骨长入多孔泡沫涂层来加速脱矿和穿孔同种异体移植物的融合。试点结果表明，皮质骨的ppf泡沫涂层可以随着时间的推移保持强度，并且支架的孔隙度支持骨长入。该资助申请将研究(1)不同孔隙度支架的制备，(2)这些支架对聚合物修饰部分脱矿和穿孔皮质同种异体移植物的机械性能的影响，以及(3)支架涂层皮质同种异体移植物在原位大鼠胫骨移植模型中的初步评估。这些研究的最终目的是确定聚合物涂层的孔隙度和厚度的最佳组合，以便制造脱矿和穿孔皮质同种异体移植物，在整个植入过程中保持足够的机械性能，以抵抗正常的骨骼力。建议的商业应用：尽管大量皮质骨同种异体移植的总体成功率（意味着无需拐杖或支架即可恢复工作和相对正常的活动）约为75-85%，但只有50%的患者具有完全无并发症的术后过程。大约四分之一的人需要再手术，如自体移植或复制应力性骨折延迟愈合。有些患者由于感染需要切除移植物、再植、长期支具或在某些情况下截肢。如果像提议的那样成功，我们系统的临床结果将在商业上取得独特的成功。

Previous studies have shown that modification of cortical bone allografts by partial demineralization and laser-perforation may enhance their incorporation into host bone. However, these studies also showed that incorporation is commonly preceded by bone resorption which could result in premature mechanical failure. The purpose of this proposal is to investigate whether incorporation of these demineralized and perforated allografts can be accelerated by coating them with a bioresorbable polymer foam based on polypropylene fumarate (PPF) with the objective of promoting bony ingrowth into the porous foam coating. Pilot results suggest that PPF-foam coating of cortical bone can maintain strength over time and that the porosity of the scaffold supported bony ingrowth. This grant application will investigate (l) the preparation of scaffolds varying in porosity, (2) the effect of these scaffolds on the mechanical properties of polymer modified partially demineralized and perforated cortical allografts, and (3) the initial evaluation of scaffold coated cortical allografts in an orthotopic rat tibial transplantation model. The ultimate objective of these studies is to determine an optimum combination of porosity and thickness of the polymer coating so as to enable the manufacture of demineralized and perforated cortical allografts which retain sufficient mechanical properties to resist normal skeletal forces throughout the incorporation process. PROPOSED COMMERCIAL APPLICATIONS: Although the overall success rate for massive cortical bone allografts, implying return to work and engagement in relatively normal activities without crutches or braces, is approximately 75-85%, only 50% of these patients have an entirely uncomplicated postoperative course. About a quarter of the total group require reoperations such as autologous grafting or replating for stress fractures delayed unions. Some patients require excision of the graft because of infection, reimplantation, long-term bracing or in some cases amputation. If as successful as proposed, the clinical outcomes of our system will be uniquely successful commercially.