I am sticking my neck out a bit here, because of course the dictionary translation of "traumatólogo" is "traumatologist", but I don't think it's as simple as that, and I suspect you don't either, otherwise you wouldn't have asked the question. I am thinking here of British English usage in particular.

As a patient , it has always struck me how many common the term "traumatólogo" is in Spain and how unusual "traumatologist" is in the UK. On the other hand, the UK is full of orthopaedic surgeons, but although "ortopedia" is certainly a standard medical term in Spain, there don't seem to be all that many "ortopedistas" around.

The fact is (I think) that Spanish "traumatólogos" are not just traumatologists in the strict sense. As well as accidental injuries, they also deal with congenital and acquired physical defects. In fact, they are to all intents and purposes orthopaedic surgeons.

Here's the Spanish Wikipedia page, which matches my impression:

"La Traumatología es la parte de la medicina que se dedica al estudio de las lesiones del aparato locomotor.
En la actualidad esta definición es insuficiente, ya que la especialidad se extiende mucho más allá del campo de las lesiones traumáticas; abarca también el estudio de aquellas congénitas o adquiridas, en sus aspectos preventivos, terapéuticos, de rehabilitación y de investigación, y que afectan al aparato locomotor desde la niñez hasta la senectud."
http://es.wikipedia.org/wiki/Traumatología_y_Ortopedia

Conversely, in the NHS the career path is called Trauma and Orthopaedic Surgery, and people who follow that path are commonly called orthopaedic surgeons:
https://www.medicalcareers.nhs.uk/specialty_pages/surgery/tr...

So I believe the functionally equivalent term is actually orthopaedic surgeon.

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Note added at 1 hr (2013-02-27 11:50:15 GMT)
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The word "orthopaedist" is in the dictionary, but no one uses it in real life.