Tough one. Prussia was- is, since it's still a province of Poland- on the periphery of the German-speaking lands, and the Poles had a tight hold over it since the fifteenth century at least.
So bear with me here, but according to five minutes of research, the key trait that doomed Prussia was its crappy rulers. Even in its pre-Polish incarnation as the Teutonic Order, most of its grandmasters already had one foot in the grave. And after it was forcibly secularized(?), its Dukes were notoriously inward-looking... until the Prussian War of Independence in 1683, which saw a Piast (old, loyal Polish family) take the throne.
So of nearby rulers, who actually had a chance at intervening in Polish police actions, what seems to be a consistently reliable dynasty is the Hohenzollerns. Middling but competent, they delivered a fair number of brilliant administrators and generals, until the neutering of Brandenburg in the Baltic Conflagration.
Other than that it looks like you'd need a miracle. A miracle of the House of Brandenburg, if I might be glib (has a certain ring to it, I think).