Bobyn J D, Pilliar R M, Cameron H U, Weatherly G C
Acta Orthop Scand. 1981;52(2):145-53. doi: 10.3109/17453678108991775.
Porous surfaced femoral components of hip prostheses stabilized by tissue ingrowth are often situated a certain distance away from the endosteal cortex in the diaphysis. The purpose of this study was to examine the significance of this space between an implant and the cortex on bone growth into the porous surface of the implant. Intramedullary rods of different diameters with porous surface regions made of powder metal were inserted into the femurs of adult beagles. The rods had outside diameters of 2.5, 3.2, 4.5, and 5.5 millimeters; this variation produced endosteal bone-implant surface spaces ranging from 0 to 4 millimeters. The animals were sacrificed at 4, 8, 12, and 16 weeks. Histological sections revealed that by 12 weeks the implants became generally surrounded by a thin shell of spongy bone which was joined to the endosteal cortex by bony trabeculae. This feature was most prominent for implants which were approximately 2 millimeters or less from the endosteum. Denser, more haversian-like bone developed up to and within those areas of implants which were in contact with the cortex. The development of this intramedullary type of bone could significantly contribute to the fixation strength of clinical porous surfaced prostheses whose stems do not completely fill the medulla.
通过组织长入实现稳定的髋关节假体多孔表面股骨部件，在骨干中通常与骨内膜皮质保持一定距离。本研究的目的是探讨植入物与皮质之间的这一间隙对骨长入植入物多孔表面的意义。将具有粉末金属制成的多孔表面区域的不同直径的髓内杆插入成年比格犬的股骨中。这些杆的外径分别为2.5、3.2、4.5和5.5毫米；这种变化产生了从0到4毫米的骨内膜骨-植入物表面间隙。在4、8、12和16周时处死动物。组织学切片显示，到12周时，植入物通常被一层薄的海绵骨壳包围，该海绵骨壳通过骨小梁与骨内膜皮质相连。对于距离骨内膜约2毫米或更小的植入物，这一特征最为明显。在与皮质接触的植入物区域及其内部，形成了更致密、更类似哈弗斯系统的骨。这种髓内型骨的形成可显著有助于临床多孔表面假体的固定强度，其柄部并未完全填满髓腔。
