Lewandrowski K U, Gresser J D, Wise D L, Trantol D J
Orthopaedic Research Laboratories, Massachusetts General Hospital, Boston 02114, USA.
Biomaterials. 2000 Apr;21(8):757-64. doi: 10.1016/s0142-9612(99)00179-9.
Bioresorbable bone graft substitutes may significantly reduce the disadvantages associated with autografts, allografts and other synthetic materials currently used in bone graft procedures. We investigated the biocompatibility and osteointegration of a bioresorbable bone graft substitute made from the unsaturated polyester poly(propylene-glycol-co-fumaric acid), or simply poly(propylene fumarate), PPF, which is crosslinked in the presence of soluble and insoluble calcium filler salts. Four sets of animals each having three groups of 8 were evaluated by grouting bone graft substitutes of varying compositions into 3-mm holes that were made into the anteromedial tibial metaphysis of rats. Four different formulations varying as to the type of soluble salt filler employed were used: set 1--calcium acetate, set 2--calcium gluconate, set 3--calcium propionate, and set 4--control with hydroxapatite, HA, only. Animals of each of the three sets were sacrificed in groups of 8 at postoperative week 1, 3, and 7. Histologic analysis revealed that in vivo biocompatibility and osteointegration of bone graft substitutes was optimal when calcium acetate was employed as a soluble salt filler. Other formulations demonstrated implant surface erosion and disintegration which was ultimately accompanied by an inflammatory response. This study suggested that PPF-based bone graft substitutes can be designed to provide an osteoconductive pathway by which bone will grow in faster because of its capacity to develop controlled porosities in vivo. Immediate applicability of this bone graft substitute, the porosity of which can be tailored for the reconstruction of defects of varying size and quality of the recipient bed, is to defects caused by surgical debridement of infections, previous surgery, tumor removal, trauma, implant revisions and joint fusion. Clinical implications of the relation between developing porosity, resulting osteoconduction, and bone repair in vivo are discussed.
可生物吸收的骨移植替代物可能会显著减少与自体骨移植、异体骨移植以及目前在骨移植手术中使用的其他合成材料相关的缺点。我们研究了一种由不饱和聚酯聚（丙二醇 - 共 - 富马酸），即聚（富马酸丙酯）（PPF）制成的可生物吸收骨移植替代物的生物相容性和骨整合情况，该材料在可溶性和不溶性钙填充盐存在下交联。通过将不同成分的骨移植替代物注入大鼠胫骨干骺端前内侧制成的3毫米孔中，对四组每组三只、每组8只动物进行了评估。使用了四种不同配方，其可溶性盐填充剂类型不同：第1组 - 醋酸钙，第2组 - 葡萄糖酸钙，第3组 - 丙酸钙，第4组 - 仅使用羟基磷灰石（HA）作为对照。三组中的每组动物在术后第1、3和7周以每组8只的方式进行处死。组织学分析表明，当使用醋酸钙作为可溶性盐填充剂时，骨移植替代物的体内生物相容性和骨整合最佳。其他配方显示植入物表面侵蚀和崩解，最终伴有炎症反应。这项研究表明，基于PPF的骨移植替代物可以设计成提供一种骨传导途径，由于其在体内形成可控孔隙的能力，骨能够更快生长。这种骨移植替代物可立即应用于因感染手术清创、既往手术、肿瘤切除、创伤、植入物翻修和关节融合导致的缺损，其孔隙率可根据受体床不同大小和质量的缺损进行定制。讨论了体内形成孔隙、由此产生的骨传导与骨修复之间关系的临床意义。
