Adapter assemblies selectively interconnect a surgical end effector that is configured to perform at least a pair of functions and a surgical device that is configured to actuate the end effector. The adapter assembly includes an adapter knob housing configured and adapted for connection with the surgical device and to be in operative communication with each of the at least one rotatable drive shaft of the surgical device. The adapter knob housing defines a lumen extending longitudinally therethrough and a ring gear formed in an inner surface of the lumen of the adapter knob housing. The ring gear defines an internal array of gear teeth which are engaged with a spur gear of a rotatable drive shaft. The adapter knob housing may be a unitary member and may be formed of plastic.