Jo Miller Orthopaedic Research Laboratory, Montreal General Hospital, 1650 Cedar Avenue, Room LS1-409, Montreal, QC, H3G1A4, Canada,
Clin Orthop Relat Res. 2014 Feb;472(2):687-94. doi: 10.1007/s11999-013-3120-6.
Fixation of cementless orthopaedic implants is not always achieved, particularly in challenging scenarios such as revision surgery, trauma, and tumor reconstruction. An adjunct therapy for improving implant fixation would improve the reliability and durability of certain reconstructive procedures.
QUESTIONS/PURPOSES: The purpose of this study was to determine the effect of local elution of the bisphosphonate alendronic acid on bone formation around porous titanium implants in an animal model.
Porous-coated cylindrical rods were coated with either 0.2 mg or 1.0 mg alendronic acid before bilateral surgical implantation into the femoral intramedullary canals of 10 experimental dogs. Twelve weeks after surgery, the femora were harvested and scanned with micro-CT to quantify the percentage volume of bone within the immediate periimplant space. Four femora from two dogs were also processed for undecalcified thin-section histology and analysis with backscattered scanning electron microscopy. Three histologic sections from each of these four femora were anatomically matched with transverse micro-CT sections to enable direct comparison of the area fraction of bone within the periimplant space.
Compared with paired controls, micro-CT analysis showed that local elution of alendronic acid increased periimplant bone at both doses of 0.2 mg (+52%, p = 0.01) and 1.0 mg (+152%, p = 0.004) with 1.0 mg resulting in a 2.9-fold greater mean relative increase compared with 0.2 mg (p = 0.002). Micro-CT measurements of periimplant bone formation correlated very strongly with the backscattered scanning electron microscopy measurements (R = 0.965, p < 0.001).
Local elution of alendronic acid causes a dose-dependent net increase in periimplant bone formation in an animal model.
This concept has potential to improve the biologic fixation of porous reconstructive implants.
非骨水泥型骨科植入物的固定并不总是能够实现，特别是在翻修手术、创伤和肿瘤重建等具有挑战性的情况下。辅助治疗方法可改善植入物固定，从而提高某些重建手术的可靠性和耐用性。
问题/目的：本研究的目的是确定局部洗脱双膦酸盐阿仑膦酸对动物模型中多孔钛植入物周围骨形成的影响。
在 10 只实验犬的双侧股骨骨髓腔内分别植入涂有 0.2mg 或 1.0mg 阿仑膦酸的多孔涂层圆柱形棒。手术后 12 周，取出股骨并进行微 CT 扫描，以定量测量植入物周围即刻空间内的骨体积百分比。来自 2 只犬的 4 只股骨还进行了未脱钙薄切片组织学处理和背散射扫描电子显微镜分析。将这 4 只股骨的 3 个组织学切片与横断微 CT 切片进行解剖匹配，以便在植入物周围空间内直接比较骨面积分数。
与配对对照相比，微 CT 分析显示，局部洗脱阿仑膦酸可增加两种剂量（0.2mg：+52%，p=0.01；1.0mg：+152%，p=0.004）的植入物周围骨形成，1.0mg 导致的平均相对增加幅度是 0.2mg 的 2.9 倍（p=0.002）。植入物周围骨形成的微 CT 测量与背散射扫描电子显微镜测量非常相关（R=0.965，p<0.001）。
在动物模型中，局部洗脱阿仑膦酸可导致剂量依赖性的植入物周围骨形成净增加。
这一概念有可能改善多孔重建植入物的生物学固定。
