Bone and Joint Institute, Western University, London, Ontario, Canada.
Department of Medical Biophysics, Western University, London, Ontario, Canada.
J Orthop Res. 2020 Jul;38(7):1627-1636. doi: 10.1002/jor.24706. Epub 2020 May 15.
The aim of this study was to obtain micro-computed tomography derived measurements of the rat proximal femur, to create parameterized rat hip implants that could be surgically installed in a clinically representative small animal model of joint replacement. The proximal femoral anatomy of N = 25 rats (male, Sprague-Dawley, 390-605 g) was quantified. Key measurements were used to parameterize computer-aided design models of monoblock rat femoral implants. Linear regression analysis was used to determine if rat hip dimensions could be predicted from animal weight. A correlation analysis was used to determine how implants could be scaled to create a range of sizes. Additive manufacturing (3D printing) was used to create implants in medical-grade metal alloys. Linear regressions comparing rat weight to femoral head diameter and neck-head axis length revealed a significant nonzero slope (P < .05). Pearson's correlation analysis revealed five significant correlations between key measurements in the rat femur (P < .05). Implants were installed into both cadaveric and live animals; iterative design modifications were made to prototypes based on these surgical findings. Animals were able to tolerate the installation of implants and were observed ambulating on their affected limbs postoperatively. Clinical significance: We have developed a preclinical rat hip hemiarthroplasty model using image-based and iterative design techniques to create 3D-metal printed implants in medical-grade metal alloys. Our findings support further development of this model for use as a low-cost translational test platform for preclinical orthopaedic research into areas such as osseointegration, metal-on-cartilage wear, and periprosthetic joint infection.
本研究旨在通过微计算机断层扫描获取大鼠股骨近端的测量值，创建可在具有代表性的小型动物关节置换模型中进行手术植入的参数化大鼠髋关节植入物。对 N=25 只雄性 Sprague-Dawley 大鼠（体重 390-605g）的股骨近端解剖结构进行了量化。关键测量值用于对单体大鼠股骨植入物的计算机辅助设计模型进行参数化。线性回归分析用于确定大鼠髋关节尺寸是否可以根据动物体重来预测。相关性分析用于确定如何对植入物进行缩放以创建一系列尺寸。使用增材制造（3D 打印）技术在医用金属合金中制造植入物。比较大鼠体重与股骨头直径和头颈轴长度的线性回归显示斜率非零（P<0.05）。皮尔逊相关性分析显示大鼠股骨的关键测量值之间存在五个显著相关性（P<0.05）。将植入物安装到尸体和活体动物中；根据这些手术结果对原型进行了迭代设计修改。动物能够耐受植入物的安装，并在术后观察到患肢活动。临床意义：我们使用基于图像和迭代设计技术的临床前大鼠髋关节半髋关节置换模型创建了 3D 金属打印植入物，这些植入物使用医用金属合金制造。我们的研究结果支持进一步开发这种模型，将其用作临床前骨科研究领域（如骨整合、金属对软骨磨损和假体周围关节感染）的低成本转化测试平台。
