Abstract: A tool for breaking a shaft includes two aligned tubular elements (20, 22), each having an end portion for receiving a contiguous length of the same shaft (2). Means are provided for locking each end portion against rotation relative to the shaft length received therein, and the elements are adapted for rotation relative to one another with the end portions so locked, to relatively twist the shaft lengths and shear the lengths at the interface between them. The element end portions will normally have juxtaposed faces, and it is preferred that the faces are moved towards each other during the relative rotation and as the shaft lengths are twisted relative to each other. This assists in achieving a substantially planar face at the fracture plane. A compressible washer may be disposed between the juxtaposed faces. This can stabilize the moving parts as the shaft is broken, although normally screw threads on the tubular elements will effect the movement of the element.

Abstract: A tool for breaking a shaft includes two aligned tubular elements (20, 22), each having an end portion for receiving a contiguous length of the same shaft (2). Means are provided for locking each end portion against rotation relative to the shaft length received therein, and the elements are adapted for rotation relative to one another with the end portions so locked, to relatively twist the shaft lengths and shear the lengths at the interface between them. The element end portions will normally have juxtaposed faces, and it is preferred that the faces are moved towards each other during the relative rotation and as the shaft lengths are twisted relative to each other. This assists in achieving a substantially planar face at the fracture plane. A compressible washer may be disposed between the juxtaposed faces. This can stabilize the moving parts as the shaft is broken, although normally screw threads on the tubular elements will effect the movement of the element.

Abstract: A method of implanting an acetabular cup which includes the step of preparing an acetabular socket to receive a cup, placing cement in the acetabular socket before or after locating a tube in line with the acetabular socket and inserting the acetabular cup through the tube and into the socket.

Abstract: A profile gauge for use with an acetabular cup loading tube provided with a skirt or flange characterized by adjustable means for measuring and indicating the diametric profile of the mouth of the rim area adjacent thereto of an acetabular socket into which an acetabular cup is to be implanted and includes means for removably locating said adjustable means on a loading tube to indicate on the skirt thereof the measured diameter profile.

Abstract: A method of implanting an acetabular cup which includes the step of preparing an acetabular socket to receive a cup, placing cement in the acetabular socket before or after locating a tube in line with the acetabular socket and inserting the acetabular cup through the tube and into the socket.

Abstract: A prosthesis having attachment portion for insertion into or attachment to a patient's bone without bone cement. Parts of the attachment portion on the prosthesis are attached to the bone are covered with a mantle of synthetic resin material and which has a roughened outer surface with bone fragments or calcium phosphate fragments embedded therein.

Abstract: A femoral component of a replacement hip joint has a collarless stem including a shoulder for fixing in a medullary canal by cement. The component has a stem beneath the shoulder having a straight taper and the anterior and posterior faces of the stem each having a concave surface formed by a longitudinally extending curve from the top of the shoulder to the distal tip of the stem.

Abstract: An intramedullary intertrochanteric fracture fixation appliance has an intramedullary rod having an angulated opening to receive a femoral neck screw. The femoral neck screw has a threaded portion at its proximal end of predetermined diameter. A locking element is provided which acts between the neck screw and the wall of the angulated opening to prevent relative rotation between the screw and the rod.

Abstract: A prosthetic tibial component has a tibial tray having an underside for engaging a prepared tibial plateau. The tibial component has a stem having a tapered connection at one end. The stem has a non-symmetrically shaped bone engagement element extending therefrom. The tray includes a tapered connection element for mating with the tapered connection element on the stem. The tray includes an alignment element for locating and engaging the bone engagement element on the stem to locate the stem at a predetermined position relative to the tibial plateau.

Abstract: A total hip replacement femoral component has an outer surface shaped to conform to an acetabular socket and has an internal bore adapted to receive a femoral head. The head has been shaped and dimensioned to provide a spigot to enter the bore and be locked in place by a cement mantle between the bone and the walls of the bore. The head allows the hip component to move further over said spigot and re-lock should the cement creep or thereby any movement in the bone after assembly. The internal bore is inwardly tapered. Thus the taper can be co-axial with the femoral neck, but there may be advantages in orientating the axis of the taper as close to vertical as possible when in position so that it is closer to the average force vector acting on the femoral head during human activity.

Abstract: A prosthetic intramedullary femoral prosthesis provided with a separate preformed sheath made from an acrylic material which is dimensioned to enclose the prosthesis stem from the distal tip to a location on the stem which will be adjacent the proximal cut end of the femur with which it will be used.

Abstract: An intramedullary intertrochanteric fracture fixation appliance comprising an intramedullary rod having an angulated opening to receive a femoral neck screw, said rod having a co-axial bore extending into said angulated opening, anti-rotation means located in said bore to selectively prevent rotation of said neck screw in the rod and the open end of said bore being provided with means to positively locate a removable fitting device on the proximal end of the rod and so that said anti-rotation means can be operated with the fitting device in position.

Abstract: An acetabular cup for use in a total hip prosthesis includes an implant/cement interface portion for location in a cement mantle. The cup has an enclosure element for allowing the cup to slide lengthwise to re-engage itself in the cement mantle to accommodate creep or movement thereof. Thus, should there be a tendency for the cup to become loose, the construction according to the invention is intended to relock the cup within the cement mantle. Thus, if the bone remodels, then the cement mantle will creep to re-adapt itself to the bone and the implant will re-engage in the cement mantle accommodating to the movement of the cement. If the bone cement is too highly stressed in places, it will creep in order to relieve this stress and the implant will re-settle.

Abstract: A tibial component for a replacement knee prosthesis comprising a tibial tray for connection to a suitably prepared tibia has a tray carrying fixed lateral and medial condylar bearing components. Only the medial component has a shock absorber located beneath it.

Abstract: A tibial component of a replacement knee prosthesis includes a tibial tray for connection to a suitably prepared tibia. The upper surface of the tray carries one or more bearing components provided with means for altering the position of the tibia relative to its co-operating femur by alternatively altering one or more of the following variables: medio-lateral offset, antero-posterior offset, antero-posterior tilt, tibial rotation and tibial condyle depression profile. The tray carries either one bearing component which cooperates with both femoral condyles, or two distinct bearing components, each of which cooperates with a single femoral condyle.

Abstract: A modular prosthesis assembly for replacement of at least part of a joint and part of a bone shaft including a mounting component provided with a connection portion and at least two joint components of similar shape but different dimensions and which can be connected alternatively to the mounting component, each of the joint components having an engagement portion and a connection part adapted for connection to the connection portion of the mounting component, the joint components each providing part of a bone shaft and part of a joint which can cooperate with an appropriate part of a natural or artificial joint.