Design and fabrication of uncemented femoral prosthesis using CAD/CAM/Robotic integration method

背景:生物型股骨柄假体无菌松动是全髋关节置换失败的主要因素,减少无菌松动的先决条件是增加股骨柄假体在股骨髓腔中的填充率。目的:得到定制式股骨柄假体在髓腔中的填充率,验证计算机辅助设计/计算机辅助制造/工业机器人加工(CAd/CAM/rObOTIC)集成方法和机器人磨削的有效性。方法:利用CT数据重建股骨髓腔三维模型,在此三维模型基础上设计股骨柄假体的柄体,依据标准直柄股骨柄假体近端模型设计股骨柄假体的其余部分。将设计的股骨柄假体模型导入CAd/CAM/rObOTIC集成系统生成机器人磨削轨迹,利用该轨迹对股骨柄假体进行磨削加工。将加工好的股骨柄假体与股骨髓腔匹配,分析股骨柄假体在髓腔中的填充率。结果与结论:实验结果表明,定制式股骨柄假体在髓腔中有良好的填充率,髓腔的解剖结构可以阻止股骨柄假体的扭转,获得股骨柄假体在髓腔中的稳定固定。BACKGROUND: In total hip replacements, aseptic loosening of uncemented femoral hip prosthesis is the main reason for the failure of artificial hip replacement, the prerequisite of reducing aseptic loosening of prosthesis is to increase filling area of femoral prosthesis in femoral cavity.OBJECTIVE: To obtain the filling rate of customized femoral prosthesis in femoral cavity and verify the validity of the methods of CAD/CAM/Robotic integration and the robot grind.METHODS: In this paper, the CT data of femur were used to reconstruct three-dimensional model of femoral cavity.According to this model, a custom uncemented femoral hip prosthesis was designed, then the model of this custom prosthesis was imported into the CAD/CAM/Robotic software to generate cut path.After the cut path was imported into the robotic controller, the custom prosthesis can be fabricated, then this custom prosthesis was inserted into the femoral cavity, and the filling result of the custom prosthesis in femoral cavity was analyzed.RESULTS AND CONCLUSION: The experiment results showed that the customized prosthesis in femoral cavity achieved good filling result, the structure of femoral cavity resisted the rotation of the customized prosthesis in femoral cavity, and the customized prosthesis obtained stable fixation in the femoral cavity

A quantitative research based on CT three dimensional reconstruct of personalized hip prosthesis and porcine femoral canal fixed

目的基于CT三维重建个性化设计猪股骨髋关节假体与骨髓腔接触率的定量研究。方法选择猪股骨,拍摄实验前正侧位,双斜位片,再运用CT进行横断面扫描,获得CT数据后三维重建。基于CT三维重建数据,运用机器人磨削个性化假体,使其成为与髓腔完全匹配的定制假体。匹配后,拍摄实验后正侧位片,计算定制假体与髓腔接触的骨皮质或者骨松质的表面积以及接触率。结果通过计算,个性化假体近端表面与骨髓腔直接接触率为90.8%,与医疗机器人辅助扩髓组获得的假体表面与骨髓腔直接接触率相近,远较传统手工扩髓组获得的假体近端表面与骨髓腔直接接触率高。结论基于CT三维重建个性化股骨假体与猪股骨髓腔初始固定直接接触率为90.8%,可获得良好的接触率。Objective A quantitative research based on CT three dimensional reconstruct of personalized hip prosthesis and porcine femoral canal fixed.Methods Choose a pig femur and get photos of its lateral and double oblique positions before the experiment, then use CT scanning in cross-section.Reconstruct three-dimension on obtaining CT datas, grind personalized prosthesis by using robot and making it perfectly matched with femoral canal of customized prosthesis.Take photos of its lateral when personalized prosthesis matched with femoral canal of pig after the experiment.Then calculate the surface area and contact rate of the cancellous bone or cortical bone respectively where the personalized prosthesis contact with femoral canal.Results Through calculation, personalized prosthesis proximal surface directly contact with the bone marrow cavity at a rate of 90.8% which is close to the rate that prosthesis surface directly contact with the bone marrow cavity which acquired by the medical robot-assisted reaming group.And further the rate is higher than the rate obtained by the traditional manual expanding medullary group.Conclusion The direct contact rate based on CT three dimensional reconstruct of personalized femoral prosthesis and porcine femoral canal initial fixed is 90.8% making it possible to have a good fixed

A Method and Relevant Experiment for Individualized Artificial Hip Joint Handle of Robot Grinding

人体髋关节髓腔具有S型的形状,并且具有个性化特征.现有标准型的直柄人工髋关节与病人髓腔匹配时将形成三点接触,降低了人工髋关节与病人髓腔的贴合度.利用病人的CT数据重建髋关节髓腔的三维模型,将该三维模型作为人工髋关节关节柄的设计模型,并利用机器人磨削技术将该关节柄复制到铜棒上,通过检测加工后的关节柄与三维模型的尺寸误差,验证机器人磨削个性化人工髋关节的可行性.实验结果表明,关节柄磨削完成后,在其上取断面进行测量,其与髓腔三维模型的最大误差为0.624 8MM.Human hip joint has an S-shaped canal with personalized feature.The existing standard straight shank type artificial hip joint matching with the medullary cavity of the patient,will form a three-point contact and reduce the fit precision between joint and femoral canal.In this paper,the patient′s CT data is applied to reconstruct the three-dimensional model of medullary cavity for designing the artificial hip joint handle model,then,the artificial hip joint handle model is copied to the copper bar by using robotic grinding technology.It is verified that the feasibility of the robot grinding individual artificial hip joint by measuring the size error between the processed shank and the three-dimensional model.Experimental results show that different sections are fetched in three dimensional model for measurement when grinding has been accomplished,and the maximum error is 0.624 8mm.国家自然科学基金(50875222

Robot Grinding Technology Making Custom Uncemented Femoral Hip Prosthesis

非骨水泥股骨柄假体在股骨髓腔中的低填充率是股骨柄假体无菌松动的主要因素,为了提高股骨柄假体与股骨髓腔的填充率,利用机器人磨削系统加工与猪腿骨匹配的股骨柄假体.其方法是利用CT数据重建股骨髓腔三维模型,依据该三维模型设计股骨柄假体.将设计的股骨柄假体模型导入CAd/CAM/rObOTIC集成系统,生成磨削股骨柄假体的加工轨迹.加工轨迹后处理后导入机器人仿真软件中运行,消除刀具与CAd模型的干涉并生成机器人加工轨迹;将机器人加工轨迹下载到控制器中,磨削加工股骨柄假体.将股骨柄假体与猪腿骨髓腔匹配,分析股骨柄假体在髓腔中的填充率,验证机器人磨削技术和CAd/CAM/rObOTIC集成方法加工定制式股骨柄假体的可行性.实验结果表明,定制式股骨柄假体在猪腿骨髓腔中有好的填充率.The low filling rate of the uncemented femoral hip prosthesis to the femoral cavity is a main reason of unsuccessful total hip replacements.For purposes of improving the filling rate of the prosthesis in femoral cavity,in this paper,a robotic system is used to mill the prosthesis.The CAD model of prosthesis is designed according to reconstructed model of the CT data of pig femur.when the CAD model of prosthesis is imported to CAD/CAM/Robotics software,the milling path of robotic is produced.During the course of runing the milling path at CAD/CAM/Robotics software,the conflict of the milling machine and CAD model will be eliminated.After the milling path is imported into the robotic controller,the custom prosthesis can be fabricated.When the prosthesis that is fabricated by the robotic milling system is inserted into the femoral cavity,the filling rate of the prosthesis in femoral cavity can be analysed.The experiment results show that nice result of the custom prosthesis in femoral cavity can be obtained,the robotic milling system and CAD/CAM/Robotic integration method can be used to mill custom prosthesis