Reconstruction of severe bone defects in revision total knee arthroplasty(TKA)remains a challenge for orthopaedists.The progression of medical imaging and additive manufacturing technology has enabled the rapid manufa...Reconstruction of severe bone defects in revision total knee arthroplasty(TKA)remains a challenge for orthopaedists.The progression of medical imaging and additive manufacturing technology has enabled the rapid manufacture of custom-made implants,and 3D-printed augments with interconnected pore structures have become an alternative approach for the reconstruction of bone defects in revision TKA,especially in patients with complex bone defects.The size and location of the bone defect were determined by thin-layer computed tomography(CT;layer thickness is 1 mm)after reduction of artifacts.The 3D reconstruction models of the host bone were obtained based on thin-layer CT imaging.The custom-made augmentation was designed according to the 3D reconstruction bone model.The augmentation had an interconnected porous structure on the bone-implant interface to achieve biological fixation.After the design was complete,the 3D model of augment was exported in STL format,and augments were fabricated with Ti6Al4V powder using electron beam melting.Thin-layer CT and 3D reconstruction bone models are accurate methods for evaluating periprosthetic bone loss after artifact reduction.The 3D-printed augments perfectly match the bone defects during surgery.3D-printed augmentation is an effective approach for the reconstruction of bone defects in revision TKA.Thus,surgeons and engineers should carefully evaluate the bone defect during augment design to avoid a mismatch between the augment and host bone.展开更多
This paper investigates the hydrodynamic characteristics of floating truncated cylinders undergoing horizontal and vertical motions due to earthquake excitations in the finite water depth.The governing equation of the...This paper investigates the hydrodynamic characteristics of floating truncated cylinders undergoing horizontal and vertical motions due to earthquake excitations in the finite water depth.The governing equation of the hydrodynamic pressure acting on the cylinder is derived based on the radiation theory with the inviscid and incompressible assumptions.The governing equation is solved by using the method of separating variables and analytical solutions are obtained by assigning reasonable boundary conditions.The analytical result is validated by a numerical model using the exact artificial boundary simulation of the infinite water.The main variation and distribution characteristics of the hydrodynamic pressure acting on the side and bottom of the cylinder are analyzed for different combinations of wide-height and immersion ratios.The added mass coefficient of the cylinder is calculated by integrating the hydrodynamic pressure and simplified formulas are proposed for engineering applications.The calculation results show that the simplified formulas are in good agreement with the analytical solutions.展开更多
The study aimed to explore the feasibility of an image registration technique for assessing the accuracy of intraoperative osteotomy of pelvic tumors by 3-dimensional(3D)-printed patient-specific templates.Patients wi...The study aimed to explore the feasibility of an image registration technique for assessing the accuracy of intraoperative osteotomy of pelvic tumors by 3-dimensional(3D)-printed patient-specific templates.Patients with malignant pelvic tumors who were admitted to our hospital between March 2014 and December 2020 were retrospectively enrolled.Patients underwent hemi-pelvic resection and reconstruction by 3D-printed individualized prostheses.The registration between the designed model and the postoperative segmented model of the prosthesis was used to obtain the intraoperative osteotomy plane and reduce metal artifacts in postoperative computed tomography(CT)images.The distance and angle between the planned and actual osteotomy planes were then used to assess the accuracy of the intraoperative osteotomy.Eight patients with 13 osteotomy planes were enrolled,including four males and four females.The median age at the time of imaging examination was 44 years(range,33–54 years).All intraoperative osteotomy planes were assessed successfully.The mean distance between the planned and true intraoperative osteotomy planes was−0.69 cm(−7.5–7.35 cm),and the mean angle was 6.57°±3.36°(1.05°–11.88°).This new assessment method of registering the designed model and the postoperative CT segmented model of the prosthesis may be used to assess the accuracy of intraoperative osteotomy for pelvic tumors,using 3D printed patient-specific templates.展开更多
基金the 3D Snowball Project of Shanghai Jiao Tong University School of Medicine(No.GXQ202007)the Natural Science Foundation of Shanghai(No.20ZR1432000)+2 种基金the Project of Shanghai Collaborative Innovation Center for Translational Medicine(No.TM201814)the Clinical Research Program of the 9th People’s Hospital affiliated to Shanghai Jiao Tong University School of Medicine(No.JYLJ025)the National Natural Science Foundation of China(No.81772425)。
文摘Reconstruction of severe bone defects in revision total knee arthroplasty(TKA)remains a challenge for orthopaedists.The progression of medical imaging and additive manufacturing technology has enabled the rapid manufacture of custom-made implants,and 3D-printed augments with interconnected pore structures have become an alternative approach for the reconstruction of bone defects in revision TKA,especially in patients with complex bone defects.The size and location of the bone defect were determined by thin-layer computed tomography(CT;layer thickness is 1 mm)after reduction of artifacts.The 3D reconstruction models of the host bone were obtained based on thin-layer CT imaging.The custom-made augmentation was designed according to the 3D reconstruction bone model.The augmentation had an interconnected porous structure on the bone-implant interface to achieve biological fixation.After the design was complete,the 3D model of augment was exported in STL format,and augments were fabricated with Ti6Al4V powder using electron beam melting.Thin-layer CT and 3D reconstruction bone models are accurate methods for evaluating periprosthetic bone loss after artifact reduction.The 3D-printed augments perfectly match the bone defects during surgery.3D-printed augmentation is an effective approach for the reconstruction of bone defects in revision TKA.Thus,surgeons and engineers should carefully evaluate the bone defect during augment design to avoid a mismatch between the augment and host bone.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.52078010 and 52101321)the National Key Research and Development Program of China(Grant No.2022YFC3004300).
文摘This paper investigates the hydrodynamic characteristics of floating truncated cylinders undergoing horizontal and vertical motions due to earthquake excitations in the finite water depth.The governing equation of the hydrodynamic pressure acting on the cylinder is derived based on the radiation theory with the inviscid and incompressible assumptions.The governing equation is solved by using the method of separating variables and analytical solutions are obtained by assigning reasonable boundary conditions.The analytical result is validated by a numerical model using the exact artificial boundary simulation of the infinite water.The main variation and distribution characteristics of the hydrodynamic pressure acting on the side and bottom of the cylinder are analyzed for different combinations of wide-height and immersion ratios.The added mass coefficient of the cylinder is calculated by integrating the hydrodynamic pressure and simplified formulas are proposed for engineering applications.The calculation results show that the simplified formulas are in good agreement with the analytical solutions.
基金the Technology Project of Shanghai Science and Technology Commission(Nos.19441902700 and 18441903100)the Clinical Research Plan of SHDC(No.SHDC2020CR3083B)the Shanghai Municipal Education Commission(No.20152221)。
文摘The study aimed to explore the feasibility of an image registration technique for assessing the accuracy of intraoperative osteotomy of pelvic tumors by 3-dimensional(3D)-printed patient-specific templates.Patients with malignant pelvic tumors who were admitted to our hospital between March 2014 and December 2020 were retrospectively enrolled.Patients underwent hemi-pelvic resection and reconstruction by 3D-printed individualized prostheses.The registration between the designed model and the postoperative segmented model of the prosthesis was used to obtain the intraoperative osteotomy plane and reduce metal artifacts in postoperative computed tomography(CT)images.The distance and angle between the planned and actual osteotomy planes were then used to assess the accuracy of the intraoperative osteotomy.Eight patients with 13 osteotomy planes were enrolled,including four males and four females.The median age at the time of imaging examination was 44 years(range,33–54 years).All intraoperative osteotomy planes were assessed successfully.The mean distance between the planned and true intraoperative osteotomy planes was−0.69 cm(−7.5–7.35 cm),and the mean angle was 6.57°±3.36°(1.05°–11.88°).This new assessment method of registering the designed model and the postoperative CT segmented model of the prosthesis may be used to assess the accuracy of intraoperative osteotomy for pelvic tumors,using 3D printed patient-specific templates.
