Differences in stiffness of the interface between a cementless porous implant and cancellous bone in vivo in dogs due to varying amounts of implant motion
Differences in stiffness of the interface between a cementless porous implant and cancellous bone in vivo in dogs due to varying amounts of implant motion
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DOI：
10.1016/s0883-5403(96)80136-7
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发表时间：
1996-12-01
影响因子：
3.5
通讯作者：
Harris, WH
中科院分区：
文献类型：
--
作者：
Bragdon, CR;Burke, D;Harris, WH
为了确定进入多孔涂层的组织与植入物之间界面的力学性能，将20只成熟犬的多孔涂层圆柱形植入物插入股骨远端，并在体内以固定的微运动（0、20、40和150 μ m）每天振荡8小时，持续6周。单位角位移扭转阻力（TRIAD）反映骨-多孔涂层界面的刚度，在20 μ m位移组植入后立即为0.88 +/- 0.25 N-M/°。术后随时间增加，6周时达到最高值1.25 +/- 0.60 N-M/度。40 μ m组TRIAD初始较低（0.77 +/- 0.43 N-M/deg），随着术后时间的推移逐渐降低，6周时达到最大值0.54 +/- 0.13 N-M/deg。150 μ m组的TRIAD更低（0.24 +/- 0.10 N-M/deg），术后保持不变（0.16 +/- 0.09 N-M/deg）。组织学评估显示，20 μ m组骨长入与周围骨连续性，与牺牲时的高刚度值一致。相比之下，在40 μ m组，骨-多孔涂层界面处发现纤维骨痂和骨的混合物，与中间刚度值一致。相比之下，尽管150 μ m组的狗在多孔涂层的深处发现了骨骼，但低刚度值反映了该组界面处纤维组织的形成，因为在骨-多孔涂层界面处的大运动破坏了骨骼的生长。通过在体内动态监测单位角位移的扭转阻力，可以评估组织长入过程中骨-多孔涂层界面的力学性能。20 μ m的振荡位移与高界面刚度的稳定骨长入相适应，而40 μ m和150 μ m的运动则不兼容。
To determine the mechanical properties of the interface between the tissue ingrowth into porous coatings and the implant, porous-coated cylindrical implants were inserted into the distal femur in 20 mature dogs and oscillated in vivo 8 hours per day for 6 weeks at fixed amounts of micromotion (0, 20, 40, and 150 mu m) Applied torques and resulting displacements were recorded. The torsional resistance per unit angular displacement (TRIAD), reflecting the stiffness of the bone-porous coating interface, was 0.88 +/- 0.25 N-M/deg immediately after implantation in the 20-mu m displacement group. It increased with time after surgery, reaching a maximum of 1.25 +/- 0.60 N-M/deg at 6 weeks. The TRIAD was lower initially (0.77 +/- 0.43 N-M/deg) in the 40-mu m group and gradually decreased with time after surgery, reaching a maximum of 0.54 +/- 0.13 N-M/deg at 6 weeks. The TRIAD was even lower (0.24 +/- 0.10 N-M/deg) in the 150-mu m group initially and remained the same (0.16 +/- 0.09 N-M/deg) with time after surgery. Histologic evaluation showed bone ingrowth in continuity with the surrounding bone in the 20-mu m group consistent with the high stiffness values at sacrifice. In contrast, a mixture of fibrocallus and bone were found at the bone-porous coating interface in the 40-mu m group, consistent with the intermediate stiffness values. In contrast, despite the fact that bone was found in the depth of the porous coating in the dogs in the 150-mu m group, the low stiffness values were a reflection of fibrous tissue formation at the interface in that group, because of the large motion disrupting bony in growth at the bone-porous coating interface. By monitoring the torsional resistance per unit of angular displacement dynamically in viva, it was possible to evaluate the mechanical properties of the bone-porous coating interface as tissue ingrowth proceeded. Twenty microns of oscillating displacement was compatible with stable bone ingrowth with high interface stiffness, whereas 40 and 150 mu m of motion was not.