We know Vergo gets stronger if he uses his upper body but to what extent is completely unknown, therefore it's a non-factor.Because all you can add for Sanji is some more energy and Hell Memories, while Vergo still has his upper body, Haki, Koka, full-body Koka and his bamboo. Vergo was far more restricted.
Actually, we've seen attacks someone to spit up blood and it being described as superfluous. Law's Counter Shock busted up Vergo's face, and this is what he had to say about it
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Doffy spit up blood with Red Hawk, but it meant nothing to him. Garp's face was bleeding from Luffy's punch even more than Vergo's was from Sanji's kick. Was pre-skip Luffy pretty close to Garp then.
We know he can use Busoshoku, but to what extent is completely unknown, therefore it's a non-factor.
Look the same apply's for all that.
Sanji With both his legs and haki and HM VS All out Vergo is debatable
And from the outcome of that first fight
Vergo (The aggressor) And Sanji (The Defendant) Sanji clearly was the winner. Sanji managed to save everyone vergo was trying to kill meaning that A Crippled sanji Can get his job done better than a Half assed vergo
So Why Can't a full strength sanji beat an all out vergo