A forceps includes an instrument housing, an elongated shaft assembly extending distally from the instrument housing, and a rotation knob assembly. The rotation knob assembly is supported in the instrument housing and includes a rotation knob and an inner housing. The rotation knob is coupled to the shaft assembly and positioned to rotate about the inner housing to rotate the elongated shaft assembly relative to the instrument housing. The inner housing is coupled to the instrument housing and supports electrical contacts configured to transmit electrical energy through the rotation knob assembly.