Søballe Kjeld, Mouzin Olivier R G, Kidder Louis A, Overgaard Søren, Bechtold Joan E
Department of Orthopaedic Surgery, Aarhus University Hospital, Denmark.
Acta Orthop Scand. 2003 Jun;74(3):239-47. doi: 10.1080/00016470310014139.
We used our established experimental model of revision joint replacement to examine the roles of hydroxyapatite coating and bone graft in improving the fixation of revision implants. The revision protocol uses the Søballe micromotion device in a preliminary 8-week period of implant instability for the presence of particulate polyethylene. During this procedure, a sclerotic endosteal bone rim forms, and a dense fibrous membrane is engendered, having macrophages with ingested polyethylene and high levels of inflammatory cytokines. At the time of revision after 8 weeks, the cavity is revised with either a titanium alloy (Ti) or a hydroxyapatite (HA) 6.0 mm plasma-sprayed implant, in the presence or absence of allograft packed into the initial 0.75 mm peri-implant gap. The contralateral limb is subjected to primary surgery with the same implant configuration, and serves as control. 8 implants were included in each of the 8 treatment groups (total 64 implants in 32 dogs). The observation period was 4 weeks after revision. Outcome measures are based on histomorphometry and mechanical pushout properties. The revision setting was always inferior to its primary counterpart. Bone graft improved the revision fixation in all treatment groups, as also did the HA coating. The sole exception was revision-grafted HA implants, which reached the same fixation as primary Ti and HA grafted implants. The revision, which was less active in general, seems to need the dual stimulation of bone graft and HA implant surface, to obtain the same level of fixation associated with primary implants. Our findings suggest that the combination of HA implant and bone graft may be of benefit in the clinical revision implant setting.
我们使用已建立的翻修关节置换实验模型，来研究羟基磷灰石涂层和骨移植在改善翻修植入物固定方面的作用。翻修方案在最初8周的植入物不稳定期使用Søballe微动装置，以检测颗粒状聚乙烯的存在。在此过程中，形成了硬化的骨内膜骨边缘，并产生了致密的纤维膜，其中含有吞噬聚乙烯的巨噬细胞和高水平的炎性细胞因子。在8周后的翻修时，用钛合金（Ti）或羟基磷灰石（HA）6.0 mm等离子喷涂植入物对腔隙进行翻修，同时在初始0.75 mm的植入物周围间隙中填充或不填充同种异体骨。对侧肢体接受相同植入物配置的初次手术，并作为对照。8个治疗组每组包括8个植入物（32只狗中共有64个植入物）。观察期为翻修后4周。结果测量基于组织形态计量学和机械推出性能。翻修环境总是不如初次手术的环境。骨移植在所有治疗组中都改善了翻修固定，HA涂层也有同样效果。唯一的例外是翻修移植的HA植入物，其达到了与初次Ti和HA移植植入物相同的固定效果。一般来说活性较低的翻修似乎需要骨移植和HA植入物表面的双重刺激，才能获得与初次植入物相关的相同固定水平。我们的研究结果表明，HA植入物和骨移植的组合可能对临床翻修植入物环境有益。
