Fixing bone fractures with controlled axial interfragmentary micromotion improves bone healing; however, the optimal type of implant construct for this purpose is still lacking. The present study describes a novel axial micromotion locking plate (AMLP) construct that allows axial interfragmentary micromotion of 0.3 or 0.6 mm. We investigated whether the AMLP constructs enhance bone healing compared to an ordinary locking plate (LP) using an ovine osteotomy model. The stiffness of the constructs was tested under axial loading. We created a 3-mm osteotomy in the left hind leg tibia of sheep that was then stabilized with a 0.3- or 0.6-mm AMLP or LP construct (n = 6/group). Bone healing was monitored weekly by X-ray radiography starting from week 3 after surgery. At week 9, the specimens were collected and evaluated by computed tomography and torsional testing. We found that the AMLPs had a lower stiffness than the LP; in particular, the stiffness of the 0.6-mm AMLP construct was 86 and 41% lower than that of the LP construct for axial loads <200 and >200 N, respectively. In the in vivo experiments, tibial osteotomies treated with the 0.6-mm AMLP construct showed the earliest maximum callus formation (week 5) and the highest volume of bone callus (9.395 ± 1.561 cm3 at week 9). Specimens from this group also withstood a 27% greater torque until failure than those from the LP group (P = 0.0386), with 53% more energy required to induce failure (P = 0.0474). These results demonstrate that AMLP constructs promote faster and stronger bone healing than an overly rigid LP construct. Moreover, better bone healing was achieved with an axial micromotion of 0.6 mm as compared to 0.3 mm.

中文翻译：

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轴向微动锁定钢板结构可以促进羊截骨模型中更快、更强的骨愈合

用可控的轴向碎片间微运动修复骨折可改善骨愈合；然而，目前仍缺乏用于此目的的最佳种植体结构类型。本研究描述了一种新的轴向微动锁定板 (AMLP) 构造，它允许 0.3 或 0.6 毫米的轴向碎片间微动。我们使用绵羊截骨模型研究了与普通锁定板 (LP) 相比，AMLP 结构是否能增强骨愈合。在轴向载荷下测试结构的刚度。我们在绵羊的左后腿胫骨上做了一个 3 毫米的截骨术，然后用 0.3 或 0.6 毫米的 AMLP 或 LP 结构（n = 6/组）进行稳定。从手术后第 3 周开始，每周通过 X 射线摄影监测骨愈合情况。在第 9 周，收集标本并通过计算机断层扫描和扭转测试进行评估。我们发现 AMLP 的刚度低于 LP；特别是，当轴向载荷 <200 和 >200 N 时，0.6 毫米 AMLP 结构的刚度分别比 LP 结构低 86% 和 41%。在体内实验中，用 0.6 毫米 AMLP 结构处理的胫骨截骨术显示出最早的最大骨痂形成（第 5 周）和最大的骨骨痂体积（第 9 周时为 9.395 ± 1.561 cm3）。与 LP 组（P = 0.0386）相比，该组的样品在发生故障前承受的扭矩也大 27%，诱导故障所需的能量多 53%（P = 0.0474）。这些结果表明，AMLP 结构比过于刚性的 LP 结构促进更快和更强的骨愈合。而且，