User blog comment:Xilinoc/Ch. 577 - SWORD/@comment-11446176-20140416080500/@comment-24546844-20140416162927

Don't know if its just me but if you look closely you will notice that his released "sword" looks like an overgrow axe-like version of his old rusted sword, that would mean that maybe yes, it's basically like Yumichika's zanpakuto. As you already mentioned Zaraki's reiatsu may have been forcing his sword in an half-released form. The fact that even after knowing his sword's true name and forming abond with it the appearence didn't changed even bit (before the release comand), unlike Ichigo's Zanpakuto that reformed and fixed itself in the same situation, may prove that the rusted and worn-down blade is a characteristic of the sword itself and maybe of Zaraki's own personality like it's mentioned in his own page.