The Wear on a Novel Motion Mode Hinged Knee Prosthesis: A Finite Element Analysis / 医用生物力学

Objective To perform finite element analysis on a novel motion mode hinged knee prosthesis, and investigate the method of wear simulation on hinged prosthesis and the influence of motion mode on wear of the prosthesis. Methods Based on the finite element model of contact stress on spherical axis prosthesis, the finite element model of wear was established according to Archard wear theory. The kinematics data during different motions were input as loading condition to simulate mechanical environment of the knee arthroplasty in physiological activities. The wear results of spherical axis prosthesis were studied. Results For tibial insert, the average and maximum contact stresses during upstairs and downstairs climbing were higher than those during walking, and the cumulative wear volume during upstairs climbing was larger than that during downstairs climbing and walking. The wear mainly occurred on lower surface of tibial insert during all 3 motions. For rotating bushing, there was only a short period of contact and wear during walking, and the cumulative wear was 0. 19 mm3. Conclusions The spherical axis motion of hinged knee prosthesis can improve the mechanical environment of knee, reduce the wear of rotating bushing, and prolong the prosthesis survival. The finite element simulation can predict the wear of hinged prosthesis effectively, and provide the theoretical basis for design and improvement of the prosthesis.

Application of 3D printing technique in bone tumor surgery: state of the art / 中华骨科杂志

It is a great challenge for surgeons to make an individualized treatment plan and remove tumor accurately and completely for bone tumor patients.3D printing technique is one of the most effective methods when it comes to individualized and precise treatment in medical field.The distinctiveness and advantages of 3D printing technique can make up for the shortcomings of traditional treatments,and it also can greatly improve the level and accuracy of individualized diagnosis and treatment in bone tumor surgery.3D printing technique is usually used to make anatomical models for plan or simulation;surgical guides for drilling or osteotomy;customized implants or prostheses;models for trimming grafts and models for implants in bone tumor surgery.3D printing technique is helpful to reduce operation time and bleeding,decrease radiation exposure,reduce complications and recurrence,cut the costs,and improve the surgical accuracy and clinical outcome.Through the review of 3D printing technology in bone tumor surgery literature,we analyzed and evaluated the following aspects:surgical time,bleeding,radiation exposure,clinical outcome,complications,recurrence,accuracy and costs.And the included literatures were analyzed and summarized from the positions of bone tumor and the uses of 3D printing technique.The purpose of this study is to summarize the application of 3D printing technique in treating bone tumor patients,and to make surgeons learn more about 3D printing technique,investigate the potential advantages and the developing tendency of 3D printing technique,and develop the new ideas of 3D printing technique in bone tumor surgery.