Okada Y, Suka T, Sim F H, Gorski J P, Chao E Y
Department of Orthopedics, Mayo Clinic, Rochester, Minnesota 55905.
J Bone Joint Surg Am. 1988 Feb;70(2):160-72.
The extent of extracortical bone-bridging and ingrowth into porous-coated prostheses for the stabilization of segmental defects was studied in a canine model. Initial fixation of the implant was achieved using bone cement. Autogenous bone grafts were applied over the porous-coated segmental portion of the prosthesis to stimulate the ingrowth and formation of bone. At twelve weeks, bone-bridging and ingrowth occurred uniformly in both the titanium fibermesh and the cobalt-chromium-molybdenum beaded prostheses. Maximum formation of osseous tissue over the implants occurred at two to four weeks. More bone formed in the posterior aspect of the prosthesis. At twelve weeks, 26 per cent of the porous space of the titanium fibermesh prosthesis and 47 per cent of the porous space of the cobalt-chromium-molybdenum beaded prosthesis were filled with bone. The torsional strength and stiffness of the prosthetic midsection that contained a conical coupling joint were increased significantly due to bone-bridging and ingrowth. The cortical bone that was apposed to the segmental prosthesis showed an increase in porosity. The use of bone cement did not appear to impede new-bone formation extracortically. The initial stability of the implant and the application of sufficient autogenous bone grafts are two important factors that contribute to the ultimate stable fixation of an implant by extracortical bone formation.
在犬类模型中研究了皮质外骨桥接以及长入多孔涂层假体以稳定节段性骨缺损的程度。使用骨水泥实现植入物的初始固定。将自体骨移植到假体的多孔涂层节段部分上，以刺激骨长入和骨形成。在12周时，钛纤维网和钴铬钼珠状假体中均均匀发生了骨桥接和骨长入。植入物上骨组织的最大形成发生在2至4周。假体后方形成的骨更多。在12周时，钛纤维网假体26%的孔隙空间和钴铬钼珠状假体47%的孔隙空间被骨填充。由于骨桥接和骨长入，包含锥形连接关节的假体中部的抗扭强度和刚度显著增加。与节段性假体相邻的皮质骨孔隙率增加。使用骨水泥似乎并未妨碍皮质外新骨形成。植入物的初始稳定性和充足自体骨移植的应用是通过皮质外骨形成实现植入物最终稳定固定的两个重要因素。
