An osteotome (1) suitable for cutting through cancellous bone that is holding an orthopaedic implant requiring revision within a cavity of a bone, comprises a cylindrical waveguide (2) connectable to a source of ultrasonic vibrations at its proximal end and a blade (3) having a hollow part - cylindrical cross - section and a cutting edge (14) at its distal tip. The respective longitudinal axes (12, 13) of the waveguide (2) and the blade (3) cross at an angle of about 30°, and the waveguide (2) and blade (3) taper and curve smoothly together where they meet. The osteotome (1) is dimensioned such that a first antinode (5) of the ultrasonic vibrations is located at a proximal end of the waveguide (2), a second antinode (7) is located at the distal tip of the blade (3) and a node (6) is located where the waveguide (2) and blade (3) meet. The osteotome (1) cuts readily through cancellous bone when ultrasonically energised, its shape permitting ready access for the blade (3) between the implant and the walls of the bone so as to make a longitudinal cut along a length of a stem of the implant.
