Circular stapling device with anvil rotation locking structure

A circular stapling device comprising:

• an adaptor assembly including an elongate body, a shell assembly and an anvil retainer, the anvil retainer including a trocar having an asymmetric trocar tip, the shell assembly supported on a distal portion of the elongate body and including a staple cartridge and a housing, the staple cartridge having a body supported on the housing, the body defining an annular array of staple receiving pockets;
• an anvil assembly having a center rod, an anvil head, and an alignment member, the center rod having a proximal portion and a distal portion and defining a channel that extends from the proximal portion to the distal portion, the anvil head having an annular array of staple deforming pockets, the alignment member being positioned within the channel and configured to engage the asymmetric trocar tip of the anvil retainer when the anvil assembly is attached to the anvil retainer to rotate the anvil assembly in relation to the trocar and move the annular array of staple receiving pockets into alignment with the annular array of staple deforming pockets.