No, you don't need an article here. No context specifies that you do! It's not even a complete sentence!
Troussers = spodnie = pants (US) = underwear (UK) = Majtki. It's confusing being British with the translations interpreted to US English, then try to learn Polish too!
We actually decided to make 'trousers' the default translation... it's strange that 'pants' stayed here. Changed now.
spodnie in the English dictionary translates as pants. trousers or slacks, therefore it should be considered as a mistake