What order should I play trauma center games?

Playing the Trauma Center series in release order is usually the best way to experience the games, as it allows you to follow the progression of the gameplay mechanics and storyline: 

1. Trauma Center:  

Under the Knife (Nintendo DS)

2. Trauma Center:  

Second Opinion (Wii) - This is a remake of the original Under the Knife with enhanced graphics and additional content.

3. Trauma Center:  

New Blood (Wii)

4. Trauma Center:  

Under the Knife 2 (Nintendo DS)

5. Trauma Team (Wii) -  

This game introduces multiple playable characters with different medical specialties.