Sergio Ruiz de Galarreta has spent six months at the Department of Mechanical Engineering of the Imperial College of London (United Kingdom). Specifically in the Biomechanics Group. This group is made up of about 25 researchers (professors, post-docs and doctoral students) and is mainly dedicated to applying engineering techniques to solve current orthopaedic problems and develop new orthopaedic components.

What has the work consisted of?

First of all, we would like to briefly explain the research work we are carrying out in the Structures Area of Tecnun. One of our lines of research is the study of the behaviour of a type of porous structures (lattice structures) for their application in orthopaedic implants. The manufacture of these structures with high precision is now possible thanks to the development that has taken place in recent years in the field of Additive Manufacturing. One of the advantages of these structures is that they can reduce the stiffness of orthopaedic implants, thus resembling the stiffness of bone and avoiding a negative effect known as "stress shielding" whereby the bone starts to disappear, creating a gap between the bone and the implant and causing pain in the patient. Another advantage of these structures is that their porosity benefits the circulation of nutrients and bone growth.

The work I carried out during my stay was mainly experimental. We fabricated 100 structures with different geometries and porosities using selective laser melting, one of the FA technologies for metals. To give us an idea, these structures are composed of bars with diameters of around 200 microns. Then, after analysing the surface of the structures using scanning electron microscopy, we experimentally obtained the stiffness of these structures through compression tests and determined a model to define their behaviour based on different geometrical parameters. All this information is of vital importance to design the optimal orthopaedic implant taking into account the desired stiffness and pore size.

What conclusions have you drawn from the experience?

The truth is that spending time living in another country is always a positive experience. I have been lucky enough to have spent 6 months living in Sweden, 6 months in the United States and now 6 months in the United Kingdom and they all bring something different. What they all have in common is something that we already know very well, which is to realise how good the food is in the Basque Country.

As for the experience in London, the conclusions I draw from it are positive. Firstly, being able to work with a group that already has a great deal of experience in this area is always a plus and you learn a lot. Sharing weekly meetings with them was like attending a lecture at a congress, after all, each one presented the work done during the last 4-5 months, and therefore it was a very complete work. These presentations and the subsequent debate give you a lot of ideas and also solve some of the doubts you might be stuck on.

As for life in London, the truth is that life is quite good, there are many parks for sports, good shows, museums, restaurants of any country... but I'm still more of a small city person, I don't like the hustle and bustle of the underground at rush hour.

Have you seen similarities with Tecnun in the way they work?

The truth is that the way of working is quite similar to that of Tecnun, although it is true that it is a larger group with more funding and therefore the research they carry out is more experimental. What I found similar to Tecnun is the availability of everyone to lend a hand with anything. From the first day I arrived, some of my colleagues explained to me a couple of programmes that could be useful for the work I wanted to do, and this help among colleagues was visible in my day-to-day work. As in Tecnun, the research work was also carried out in collaboration with students from the bachelor's and master's degree programmes.

Any funny or amusing anecdotes that have happened to you during this time?

At Tecnun we have only been doing this line of research for a short time and therefore we have not yet been able to manufacture any orthopaedic implants. This is not the case at Imperial College. The first thing I saw when I arrived at the office was a shoulder implant that was being used as a door stop. I thought about taking it, but I don't think it would look aesthetically pleasing on the office door, so I left it. A little later I went down to the lab. It should be noted that his research group is made up of engineers and surgeons. I walked into the lab and saw a couple of colleagues forcing the knee of a human being to the point of breaking it. Then I got used to it and it was usual to see colleagues working with 'pieces' of leg and so on, but the first day was shocking.

And I will tell a couple of slightly more negative anecdotes. In the summer the group's activity was axe throwing. Although I'm not from Bilbao, before going I showed off a bit and told them that here in the Basque Country we control it a lot and I showed them some videos of 'aizkolaris'. Result of the test; we were 23rd out of 24...and we had to pay for a round of pints. And the second thing is to see that playing football on uneven ground can damage your hip. Who knows, maybe the first hip prosthesis that we design in the Structures Area will be for a patient called Sergio Ruiz de Galarreta, as life happens...