应用逆向工程技术测量人膝关节内外侧间室间隙和体积

背景：膝关节是人体骨骼中形态及结构最为复杂的部分，临床上常使用X射线片反映膝关节间隙狭窄程度。但X射线片是将三维的关节结构进行二维投射，因此关节拍摄定位的不同会影响测量结果，很难保证重复测量的准确性。目的：建立膝关节间隙三维模型并测量其距离和体积，为后续的模型、生物力学及相关临床研究提供基础。方法：基于逆向工程原理，采用膝关节CT断层图像，使用Mimics进行膝关节和内侧间室三维结构重建，最后导入Geomagic Studio对模型进行光滑处理并计算膝关节内、外侧间室体积。结果与结论：利用膝关节CT断层图像分别重建出膝关节三维模型的骨性结构如股骨、胫骨、腓骨，并成功构建出膝关节间隙模型。构建的膝关节三维模型和间隙模型可以任意角度或单独观察，并可以进行体视学测量。发现膝关节内外侧间隙虽然距离有差异，但体积接近，说明通过计算膝关节内、外间室的体积，可以全面的反映膝关节间隙的狭窄程度。中国组织工程研究杂志出版内容重点：人工关节；骨植入物；脊柱；骨折；内固定；数字化骨科；组织工程

Application of reverse engineering techniques to measure the distance and volume of medial and lateral compartments of human knee joint

BACKGROUND:Knee joint is the most complicated structure of human body, and X-ray is often used to reflect the stenosis of knee compartment. However, radiographs are two-dimensional projection of three-dimensional joint structure. Thus, different joint shooting locations can impact the outcomes of measurement, and it is difficult to ensure the accuracy of repeated measurements. OBJECTIVE:To build three-dimensional model of knee compartment, measure the distance and volume, and provide the basis for subsequent models, biomechanics and relevant clinical studies. METHODS:Based on the principle of reverse engineering, using CT images of the knee joint and the software of Mimics, three-dimensional model of medial compartment knee structure was reconstructed. After the model was imported and smoothed, the medial and lateral compartment volumes were finally calculated by the software of Geomagic Studio. RESULTS AND CONCLUSION:Three-dimensional model of the knee compartment, including femur, tibia and fibula, was successfully structured by CT images. The models of knee and knee compartment could be observed at any angle or observed individually, and could be measured. It was discovered that the volume of medial and  lateral compartments of knee is close, although the joint space width of them is different, which illustrates that the procedure can accurately reflect the degree of knee joint space width in the round by calculating the volume of medial and lateral compartments of knee joint through computer.