Goodman S B
Department of Orthopedics, Lund University, Sweden.
Acta Orthop Scand Suppl. 1994 Jun;258:1-43. doi: 10.3109/17453679409155227.
Motion at the interface between bone and implants for joint replacement may interfere with osseointegration and prosthesis stabilization. Particulate materials may cause foreign body and chronic inflammatory reactions resulting in bone resorption (osteolysis). The micromotion chamber (MC) and the bone harvest chamber (BHC) were implanted in the rabbit tibia, and the effects of micromotion and phagocytosable particulate materials on tissue formation within the chamber were assessed by studying bone ingrowth into a 1-mm pore. Using the MC, one short daily episode of motion (20 cycles/day, 0.5 mm amplitude) for three weeks decreased the amount of bone ingrowth. Using a different pore configuration, the same parameters of motion increased bone ingrowth. Increasing the amplitude of motion (from 0.5 to 0.75 mm), or the number of daily motion periods (from one to two per day) then decreased bone ingrowth. These studies suggest the existence of a window of externally applied strain: a small stimulus may facilitate and a large stimulus may discourage bone formation within the chamber. Cessation of a given set of motion parameters (producing primarily fibrous tissue) for an additional three weeks was accompanied by tissue differentiation into bone. Using the BHC, small, phagocytosable particles of bone cement, high density polyethylene and cobalt chrome alloy, at a concentration of 1.0 x 10(8) particles/mL, caused a foreign body reaction and inhibited the ingrowth of bone. Particles of titanium alloy had no effect on net bone formation. In studies using normal and immunodeficient rats, T lymphocytes were not a prerequisite for macrophages to phagocytose polyethylene particles. In the clinical situation, micromotion and particulate debris may be synergistic in producing prosthetic loosening. If an implant does not undergo osseointegration due to excessive micromotion, the fibrous tissue interface may provide a conduit for the subsequent migration of particles around the implant.
关节置换中骨与植入物界面处的运动可能会干扰骨整合和假体稳定性。颗粒物质可能会引发异物反应和慢性炎症反应，导致骨吸收（骨溶解）。将微动腔（MC）和骨采集腔（BHC）植入兔胫骨，通过研究骨长入1毫米孔隙来评估微动和可吞噬颗粒物质对腔内组织形成的影响。使用MC时，每天短时间的单次运动（20次循环/天，0.5毫米振幅）持续三周会减少骨长入量。使用不同的孔隙结构时，相同的运动参数会增加骨长入。增加运动振幅（从0.5毫米增加到0.75毫米）或每天运动次数（从每天1次增加到2次）会减少骨长入。这些研究表明存在一个外部施加应变的窗口：小刺激可能促进腔内骨形成，而大刺激可能抑制骨形成。停止给定的一组运动参数（主要产生纤维组织）额外三周后，组织会分化为骨。使用BHC时，骨水泥、高密度聚乙烯和钴铬合金的小的、可吞噬颗粒，浓度为1.0×10⁸颗粒/毫升，会引起异物反应并抑制骨长入。钛合金颗粒对净骨形成没有影响。在使用正常和免疫缺陷大鼠的研究中，T淋巴细胞不是巨噬细胞吞噬聚乙烯颗粒的先决条件。在临床情况下，微动和颗粒碎片可能在导致假体松动方面具有协同作用。如果植入物由于过度微动而未发生骨整合，纤维组织界面可能为颗粒随后在植入物周围的迁移提供通道。
