Accuracy of CAD/CAM and 3D printing in the treatment of feline femoral neck fracture

The aim of this study was to investigate whether a CT scan provides accurate bone surface information for feline bone model development. The second part of study consisted of 3D printing of feline femoral bone models with and without femoral neck fractures (31-B1 and 31-B2 in AO VET classification), as well as the development and 3D printing of drill guides for treatment of femoral neck fractures. The study was carried out on eight models of femoral bones and four drill guides. Initially, trial models of the right and left femurs without neck fractures and trial drill guides were used. Radiographs showed that the use of the prototype guides made it possible to drill holes in the axes of the necks of the femurs. Then, after assessing the correct operation of the guides and improving their adhesion to the bone surface by smoothing the inner surfaces of the guide bases, final bone models without femoral neck fracture, models with fractures 31-B1 and 31-B2, and final drill guides were printed. All models featured a 2.7 × 30 mm positional cortical screw. Radiographs of the models, made after inserting screws, showed that the implants were placed as intended. Also in the longitudinal sections of the heads and necks of the femoral bones of the models without fractures, the implants were positioned in the intended places.