**Case of ARGOS**

166 Biomedicine

had been lost. This was a challenging experimental case with few chances of successful outcome. Bearing in mind that there wasn't any commercially available plate, of this size and capable of being adapted to the damaged zone, the surgeon and CIMA researchers

Fig. 17. From left to right: X-ray of the fracture suffered by Baby; customized CAD design of the plate and the plate as built on EBM and finished. (Courtesy of CIMA, University of Vigo

Figure 18 shows the outcome of the surgical intervention which took place in February 2010. The surgeon decided to apply an arthrodesis with the aim of preserving the leg and recover its functionality. Fifteen days after the intervention, Baby was submitted to a control of mobility and use of the leg, an almost normal mobility was observed. In addition, Baby's owner reported that, the dog recovered its normal impulses to jump and run, even after

Fig. 18. From left to right: X-rays of Baby after the plate has been implanted and Baby

leaning on its injured leg (Courtesy of CIMA and FAUNA).

decided to design a customized titanium plate.

and Veterinary Clinic FAUNA www.clinicafauna.es).

much time without being able to walk.

Argos is an 8-month Bordeaux Mastiff of 50kg. He was diagnosed a bilateral hip dysplasia with grade I patella luxation in the right knee. Initially, the surgeon performed a triple pelvis osteotomy using a standard commercial plate. Only 3 days after the surgical intervention, during the first control, a loosening of fixation screws was detected. The proposed measure was to increase the size of the screws from M3.5 to M4.5 (Figure 19).

Fig. 19. X-rays after implanting the commercial plate: loose screws after the first intervention (left) and new bigger screws after the second intervention (right) (Courtesy of CIMA and FAUNA).

Fig. 20. From left to right: new customized design; plate after being built and finished and X-rays after the intervention (Courtesy of CIMA and FAUNA).

In order to prevent risks of screw loosening, the surgeon sought for a more feasible solution for the left hip side. Due to previous experience with customized plates, the surgeon treated left hip dysplasia with a customized plate made on EBM (Figure 20). As expected, the first revision revealed that the screws on the right hip (commercial plate) started to migrate again while the screws on the left hip (customized plate) stood as tight as after the intervention. It

Additive Manufacturing Solutions for Improved Medical Implants 169

In order to avoid this problem a specific customized plate was designed and made in Ti64

Fig. 23. Left: images showing size and weight of the customized plate. Right: post-surgery X-

All case studies exposed above have shown that the use of customized implants makes the recovery of patients faster with fewer problems related to posterior revision surgeries, such as screw loosening, plate damage and fracture. In addition, it is important to highlight that, in some of these cases, plates were successfully removed after the bone was recovered,

Regarding Additive Manufacturing, these case studies show that EBM technology is a

its production speed (less than 10 hours in the fabrication by EBM for each customized

 rough surface finish – unlike other surfaces that were polished, the plate surface in contact with the bone was left rough upon surgeon's request to allow better bone

Accordingly, the EBM process has been validated as one of the main options in case of customized implants: not expecting to replace existing production processes but to be an

As exposed previously, EBM technology enables one-step manufacturing of prostheses that combine solid and porous zones (scaffolds). By means of 3D CAD software, these scaffolds can be designed with the desired pore size, morphology, well-interconnected porosity and gradual transition from solid (body implant) to porous (scaffold), as shown on Figure 24. Designers can control the implant design and have freedom in the design of scaffolds (multiple geometrical solutions) for different pathologies. Only AM technologies are able to manufacture this kind of 3D geometries. For the time being, implants are coated with additional post-processes as plasma spray, microspheres sintering, etc. In contrast with EBM

ELI (Grade 23) ASTM F136 (ASTM, 2010) on EBM (Figure 22).

rays image of the plate (Courtesy of CIMA and FAUNA).

plate);

fixation.

detecting that the bone had completely recovered its functionality.

powerful tool for the manufacturing of customized implants due to:

excellent mechanical properties obtained in Ti6Al4V ELI;

excellent alternative with certain advantages.

**6.2 Scaffolds with controlled designed porosity** 

was also observed that a primary consolidation (the best possible) took place thanks to the proper load distribution.
