Abstract: 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 1mm) 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. 

Key words: 3D printing, revision, total knee arthroplasty, bone defect

摘要： 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 1mm) 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. 

关键词: 3D printing, revision, total knee arthroplasty, bone defect