A surgical tool arrangement comprising: a surgical instrument (13, 15) including a hub assembly (300, 500) defining a proximal end of said instrument and an elongate shaft assembly (301, 600) fixed to and projecting distally from said hub assembly, said shaft assembly at a distal end thereof defining an electrosurgical element (308, 447; 632, 627) for treating patient tissue; and a handpiece having an axis and including a housing having a proximal end and a distal end spaced therefrom, said distal end having an opening for receiving a portion of said hub assembly of said instrument, and an electrical contact arrangement mounted on said distal end and in communication with a control unit which selectively provides power to said contact arrangement, said contact arrangement including a contact member; said hub assembly (300, 500) of said instrument (13, 15) including an electrical contact arrangement (339, 340; 539, 540) disposed to mate with said contact arrangement of said handpiece to provide power to said electrosurgical element when said surgical instrument (13, 15) is mounted on said handpiece, characterized in that said contact arrangement of said hub assembly has a spring contact member (370, 371; 570, 571) including an outer leg (392, 399; 609, 599) disposed in electrical contact with said contact member of said handpiece and an inner leg (390, 395; 605, 595) electrically connected to said electrosurgical element of said instrument, said inner leg being connected to said outer leg and disposed in generally radially opposed relation with said outer leg, so that when said portion of said hub assembly (300, 500) of said surgical instrument (13, 15) is engaged within said opening of said distal end of said handpiece it causes inward compression of the spring contact member 370, 371; 570, 571) such that the outer leg is biased radially outwardly to maintain contact with the corresponding contact member 80) of the handpiece. a surgical instrument (13, 15) including a hub assembly (300, 500) defining a proximal end of said instrument and an elongate shaft assembly (301, 600) fixed to and projecting distally from said hub assembly, said shaft assembly at a distal end thereof defining an electrosurgical element (308, 447; 632, 627) for treating patient tissue; and a handpiece having an axis and including a housing having a proximal end and a distal end spaced therefrom, said distal end having an opening for receiving a portion of said hub assembly of said instrument, and an electrical contact arrangement mounted on said distal end and in communication with a control unit which selectively provides power to said contact arrangement, said contact arrangement including a contact member; said hub assembly (300, 500) of said instrument (13, 15) including an electrical contact arrangement (339, 340; 539, 540) disposed to mate with said contact arrangement of said handpiece to provide power to said electrosurgical element when said surgical instrument (13, 15) is mounted on said handpiece, characterized in that said contact arrangement of said hub assembly has a spring contact member (370, 371; 570, 571) including an outer leg (392, 399; 609, 599) disposed in electrical contact with said contact member of said handpiece and an inner leg (390, 395; 605, 595) electrically connected to said electrosurgical element of said instrument, said inner leg being connected to said outer leg and disposed in generally radially opposed relation with said outer leg, so that when said portion of said hub assembly (300, 500) of said surgical instrument (13, 15) is engaged within said opening of said distal end of said handpiece it causes inward compression of the spring contact member 370, 371; 570, 571) such that the outer leg is biased radially outwardly to maintain contact with the corresponding contact member 80) of the handpiece.