Fabrication of Patient Specific Distal Femur with Additive Manufacturing

The application of additive manufacturing in field of medical science is vast and far reaching—from anatomical models and prosthetics to biomedical research, medical education, surgery planning, etc. Designing or generating a 3D CAD model is a must for additive manufacturing. In medical science, the 3D model is mainly generated from medical imaging such as computed tomography (CT) scan, magnetic resonance imaging (MRI) scan, ultrasound scan, etc. However, the generated 3D model always has a chance of error such as dimensional inaccuracy and rough surface finished due to error in the stereolithography (STL) file generated. Therefore, optimization of the model is generally required. This paper presents a holistic approach to modelling of distal femur for 3D printing with the use of three softwares, namely: (i) 3D slicer for converting of CT scan which in DICOM format to 3D CAD model of STL file format; (ii) Ansys spaceclaim for correction of STL file error which otherwise may lead to dimensional inaccuracy, surface roughness, etc.; and (iii) Ultimaker Cura for setting the printing parameter of the model. Therefore, the model that is being processed from medical images like CT scan, MRI scan, etc. for 3D printing are free from error, ensuring a better 3D printed model. Finally, the model is printed using FDM printer and polylactic acid (PLA) filament as printing material. The dimensional deviation of the printed model from 3D CAD model was found to be 0.22 mm when measured along the transepicondylar axis (TEA) of the distal femur with a good surface finish.