An adapter assembly for selectively interconnecting a surgical loading unit and a surgical device, the adapter assembly comprising: an adapter housing configured to connect to a surgical device; an outer tube having a proximal end supported by the adapter housing and a distal end configured to connect to a surgical loading unit; and an articulation assembly at least partially disposed within the adapter housing, the articulation assembly including: a rotatable drive shaft connectable to a drive shaft of a surgical device, the drive shaft comprising a gear keyed to or integrally formed on a distal end thereof; an articulation bar connectable to an axially translatable articulation link of a surgical loading unit; at least one center tube securedly disposed within the adapter housing; a stationary sleeve keyed to the center tube; the articulation assembly being characterized in that it further comprises: a gear nut comprising a cylindrical body with external gear teeth and internal threads, rotatably disposed within adapter housing, concentric with a central longitudinal axis, the external gear teeth are rotatably coupled to the gear; a screw disposed within the cylindrical body and slidably keyed to the stationary sleeve, the screw comprising external threads that engage with internal threads of cylindrical body; and an articulation bearing disposed within an internal surface of the screw, the articulation bearing comprising an inner race that is independently rotatable relative to an outer race and that contacts said internal surface of said screw, wherein the articulation bar comprises a proximal portion secured to the inner race of the articulation bearing. an adapter housing configured to connect to a surgical device; an outer tube having a proximal end supported by the adapter housing and a distal end configured to connect to a surgical loading unit; and an articulation assembly at least partially disposed within the adapter housing, the articulation assembly including: a rotatable drive shaft connectable to a drive shaft of a surgical device, the drive shaft comprising a gear keyed to or integrally formed on a distal end thereof; an articulation bar connectable to an axially translatable articulation link of a surgical loading unit; at least one center tube securedly disposed within the adapter housing; a stationary sleeve keyed to the center tube; the articulation assembly being characterized in that it further comprises: a gear nut comprising a cylindrical body with external gear teeth and internal threads, rotatably disposed within adapter housing, concentric with a central longitudinal axis, the external gear teeth are rotatably coupled to the gear; a screw disposed within the cylindrical body and slidably keyed to the stationary sleeve, the screw comprising external threads that engage with internal threads of cylindrical body; and an articulation bearing disposed within an internal surface of the screw, the articulation bearing comprising an inner race that is independently rotatable relative to an outer race and that contacts said internal surface of said screw, wherein the articulation bar comprises a proximal portion secured to the inner race of the articulation bearing. a rotatable drive shaft connectable to a drive shaft of a surgical device, the drive shaft comprising a gear keyed to or integrally formed on a distal end thereof; an articulation bar connectable to an axially translatable articulation link of a surgical loading unit; at least one center tube securedly disposed within the adapter housing; a stationary sleeve keyed to the center tube; the articulation assembly being characterized in that it further comprises: a gear nut comprising a cylindrical body with external gear teeth and internal threads, rotatably disposed within adapter housing, concentric with a central longitudinal axis, the external gear teeth are rotatably coupled to the gear; a screw disposed within the cylindrical body and slidably keyed to the stationary sleeve, the screw comprising external threads that engage with internal threads of cylindrical body; and an articulation bearing disposed within an internal surface of the screw, the articulation bearing comprising an inner race that is independently rotatable relative to an outer race and that contacts said internal surface of said screw, wherein the articulation bar comprises a proximal portion secured to the inner race of the articulation bearing. a gear nut comprising a cylindrical body with external gear teeth and internal threads, rotatably disposed within adapter housing, concentric with a central longitudinal axis, the external gear teeth are rotatably coupled to the gear; a screw disposed within the cylindrical body and slidably keyed to the stationary sleeve, the screw comprising external threads that engage with internal threads of cylindrical body; and an articulation bearing disposed within an internal surface of the screw, the articulation bearing comprising an inner race that is independently rotatable relative to an outer race and that contacts said internal surface of said screw, wherein the articulation bar comprises a proximal portion secured to the inner race of the articulation bearing.