Image-based radiodensity profilometry measures early remodeling at the bone-callus interface in sheep
Image-based radiodensity profilometry measures early remodeling at the bone-callus interface in sheep
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DOI：
10.1007/s10237-021-01553-2
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发表时间：
2021-07
影响因子：
3.5
通讯作者：
Tianyi Ren;Karina Klein;B. von Rechenberg;S. Darwiche;H. Dailey
中科院分区：
文献类型：
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作者：
Tianyi Ren;Karina Klein;B. von Rechenberg;S. Darwiche;H. Dailey
骨愈合传统上被描述为一个四个阶段的过程：炎症反应、软骨痂形成、硬骨痂发展和重塑。在大多数骨折修复的数值机械调节模型中，重塑阶段在很大程度上被忽略了，而是支持使用预先定义的骨痂区域来捕捉早期愈合。然而，活体证据表明，重建与修复同时发生，并导致骨痂附近的皮质骨发生变化，这在骨愈合的数字模型中通常被忽略。这项研究的目的是使用图像处理技术来量化绵羊截骨手术的早期重塑。为了实现这一点，我们开发了一种基于最优化曲线拟合的放射密度轮廓测量的数值方法，以数学方式模拟横跨皮质壁和骨痂的径向的骨密度梯度。在评估了26只绵羊的数据后，我们定义了一个无量纲密度拟合函数，该函数显示在愈合早期，骨痂附近的皮质壁发生了显著的重塑，与完整的相比，密度平均降低了23%。这种拟合功能对于模拟完整骨骼和骨折修复场景中的径向密度梯度是稳健的，并且可以捕捉到各种各样的愈合反应。拟合函数也可以很容易地缩放，以便与数值模型预测进行比较，并可能有助于验证未来耦合骨折修复和重塑的机械调节模型。
Bone healing has been traditionally described as a four-phase process: inflammatory response, soft callus formation, hard callus development, and remodeling. The remodeling phase has been largely neglected in most numerical mechanoregulation models of fracture repair in favor of capturing early healing using a pre-defined callus domain. However, in vivo evidence suggests that remodeling occurs concurrently with repair and causes changes in cortical bone adjacent to callus that are typically neglected in numerical models of bone healing. The objective of this study was to use image processing techniques to quantify this early-stage remodeling in ovine osteotomies. To accomplish this, we developed a numerical method for radiodensity profilometry with optimization-based curve fitting to mathematically model the bone density gradients in the radial direction across the cortical wall and callus. After assessing data from 26 sheep, we defined a dimensionless density fitting function that revealed significant remodeling occurring in the cortical wall adjacent to callus during early healing, a 23% average reduction in density compared to intact. This fitting function is robust for modeling radial density gradients in both intact bone and fracture repair scenarios and can capture a wide variety of the healing responses. The fitting function can also be scaled easily for comparison to numerical model predictions and may be useful for validating future mechanoregulatory models of coupled fracture repair and remodeling.