Abstract: An ultrasonically-vibratable surgical tool for cement removal in revision arthroplasty, comprises an elongate solid shaft. This can be mounted at its proximal end to a source of ultrasonic vibrations, so that the shaft acts as a waveguide for propagation of the ultrasonic vibrations. The shaft has at its distal end an operative head to act on the cement. An intermediate portion of the elongate shaft is provided with at least one row of dimples extending helically along and around that portion of the elongate shaft. Each dimple is separate from each adjacent dimple. The dimples may have a shallow part-spherical profile.

Abstract: A fracture in a hollow bone is supported temporarily by a rigid plastics implant formed within a balloon within the bone. To assist implant removal, an access port, comprising a hollow cylinder, is inserted through an aperture made in an end of the bone and surrounds a proximal end of the implant. The access port is connected to a source of torsional-mode ultrasonic vibrations to soften the plastic implant and improve engagement between access port and implant. Removal of the ultrasound source allows introduction of a cutting tool through the access port, which guides it to hollow out the implant. The implant then collapses within the balloon and is withdrawn through the access port. One suitable cutting tool has a head with four helical fins separated by part-circular grooves and a concave distal face. Ultrasonically activated, the fin tips soften and cut the plastic, which flows away along the grooves.

Abstract: A torsional-mode ultrasonic vibration generator is manufactured with longitudinal slots extending along its horn which damp unwanted vibrational modes and allow it to be made significantly smaller than previous apparatus. The torsional-mode ultrasonic generator is operable with a suite of surgical tools, to perform portions of an orthopaedic arthroplasty revision procedure. Three of the tools are for removing bone cement from within a bone cavity on a prosthesis cemented into the bone cavity. Three other tools are for separating an uncemented prosthesis from ingrown bone by cutting the bone between the prosthesis and walls of the bone cavity. The seventh tool is provided with sensors to determine a separation between a bone-cutting tool head and a metal prosthesis, feedback from the sensors being used to control servo motors of an articulated mounting for the seventh tool, to maintain the separation at a desirable value.

Abstract: A fractured hollow bone can be supported by forming a rigid plastics implant within a cavity of the bone, extending across the fracture. An access port aids removal or revision of the implant. The port comprises a hollow cylinder, with a distal end inserted through an aperture in an end of the bone into the cavity to surround a proximal end of the implant. The access port is connectable to a source of torsional-mode ultrasonic vibrations, which soften the plastics material of the implant, improving engagement between the implant and a threaded formation within the distal end of the access port. Removal of the source allows the access port to act as a guide passage, in line with the elongate implant. A cutting tool introduced through the access port is thus guided so that it can be used to hollow out the implant. Once sufficiently hollowed-out, the implant collapses within its surrounding balloon.

Abstract: A torsional-mode ultrasonic vibration generator is manufactured with longitudinal slots extending along its horn which damp unwanted vibrational modes and allow it to be made significantly smaller than previous apparatus. The torsional-mode ultrasonic generator is operable with a suite of surgical tools, to perform portions of an orthopaedic arthroplasty revision procedure. Three of the tools are for removing bone cement from within a bone cavity on a prosthesis cemented into the bone cavity. Three other tools are for separating an uncemented prosthesis from ingrown bone by cutting the bone between the prosthesis and walls of the bone cavity. The seventh tool is provided with sensors to determine a separation between a bone-cutting tool head and a metal prosthesis, feedback from the sensors being used to control servo motors of an articulated mounting for the seventh tool, to maintain the separation at a desirable value.