Yeah, it seems to me everytime they make a filler arc, there has to be an episode circling around each person, for example the kitchen cooking contest was featuring Sanji, and this doctor one features Chopper.

Another example of this is episodes 131-135

131 - The First Patient! Anecdote of the Rumble Ball<--Chopper
132 - The Navigator's Mutiny! For an Unwavering Dream!<--Nami
133 - Inherited Recipe! Sanji, the Curry Expert<--Sanji
134 - I'll Make It Bloom! Manly Usopp's Eight-Shaku Ball<--Usopp
135 - Infamous Pirate Hunter! The Wandering Swordsman, Zoro<--Zoro