A tool (1, 31) for cutting bone comprises an elongate blade (7,37) connectable to a generator of longitudinal-mode ultrasonic vibrations. The blade (7,37) has two lateral cutting edges (9,10) linked by a rounded distal tip (8). A series of triangular teeth (13) extends along each cutting edge (9,10) and the distal tip (8). The blade (37) may taper towards each cutting edge (9,10) and the distal tip (8). A variant of the tool (21) comprises an elongate part-cylindrical blade (27) connectable to a generator of torsional-mode ultrasonic vibrations. The blade (27) has a cutting edge at its distal tip (28) provided with a plurality of triangular teeth (23). All forms of the tool (1, 21, 31) are particularly suitable for cutting cancellous bone around an implant to be removed during revision of a joint arthroplasty.
