Netti P A, Shelton J C, Revell P A, Pirie C, Smith S, Ambrosio L, Nicolais L, Bonfield W
IRC in Biomedical Materials, Queen Mary and Westfield College, University of London, UK.
Biomaterials. 1993 Nov;14(14):1098-104. doi: 10.1016/0142-9612(93)90211-j.
The use of fully hydrated hydrogels in the body has been well established. The forces a hydrogel generates on swelling when it is placed in a constrained space were investigated with a view to providing a mechanism for fixing a prosthesis in the intramedullary cavity. A cross-linked poly(2-hydroxyethyl methacrylate) [p(HEMA)] hydrogel was investigated as a potential material. In vitro mechanical tests were carried out to determine the stresses generated in the p(HEMA) when it was placed in water and not allowed to swell. Pull out loads of up to 375 N indicated that the system could be used successfully in vivo. Consequently, the material was placed intraosseously at two sites in a rabbit animal model, in the mid-shaft (diaphysis) and the lower end (metaphysis) of the femur. Histological examination showed there was no adverse bone response; bone was growing from the endosteal surface up to and into the hydrogel in the diaphyseal implants and surrounded the hydrogel in the metaphysis. As a result of the shape and size variations in the rabbit femur, in vivo mechanical tests were found to give lower values than those obtained in vitro.
完全水合水凝胶在体内的应用已得到充分证实。研究了水凝胶置于受限空间中溶胀时产生的力，旨在为将假体固定于骨髓腔内提供一种机制。研究了交联聚甲基丙烯酸2-羟乙酯[p(HEMA)]水凝胶作为一种潜在材料。进行了体外力学测试，以确定p(HEMA)置于水中且不允许溶胀时产生的应力。高达375 N的拔出载荷表明该系统可在体内成功使用。因此，将该材料植入兔动物模型股骨的两个部位，即骨干中部（骨干）和下端（干骺端）。组织学检查显示无不良骨反应；在骨干植入物中，骨从骨内膜表面向上生长并进入水凝胶，在干骺端，骨围绕水凝胶生长。由于兔股骨形状和尺寸的变化，发现体内力学测试得到的值低于体外测试值。
