Abstract: A positioning tool has an elongated cylindrical section for reversibly engaging an acetabular cup which is insertable through a posterior opening in the cup. The outer diameter of a proximal portion of the cylindrical section is expandable to engage the inner wall of the cup in an interference fit to prevent movement of the cup relative to the tool and hold the cup in engagement with the tool to move the cup with movement of tool to place the cup for implanting at a desired position. The expanded portion of the tool may be contracted to release it from the cup after implantation. The proximal portion, which is attached to the distal portion and separated therefrom by a partial transverse slot, is divided into semicircular sections by a diametrical vertical slot therebetween. Diametrically opposite quadrants of the proximal portion further contain elongated slots therethrough which are perpendicular to the vertical slot and spaced from the edge of the cylinder by a thin section.

Abstract: A surgical tensioning apparatus has a base, first and second bone tissue engaging elements mounted on the base and being displaceable toward and away from each other. One of the tissue engaging elements being adapted to be oriented by the tissue engaged thereby. A guide element is provided which is adjustable in relation to the base and one of the tissue engaging elements for positioning first location element to locate a cutting guide provided with cooperating second location element onto the bone to be resectioned.

Abstract: An external fixator including at least two groups of pins inserted respectively on either side of the fracture. Two vices are used for securing the pins to two hinge elements. The hinge elements are used to connect and orient the vices in relation to an external immobilizing rod which extends parallel to the bone. Each vice includes a clamping jaw and a bar intended to connect to one of the hinge elements.

Abstract: A prosthetic bearing element comprises a backing which supports a bearing liner having a bearing surface. The backing is made from a "hard" polymeric material having a minimum hardness value of 55 N/mm.sup.2 and the bearing liner is made from a "soft" elastomeric polyurethane material having a hardness value of 3.0 to 9.0 N/mm.sup.2.

Abstract: A tibial element is provided for a replacement knee prosthesis which comprises a tibial tray provided with a bearing component having medial and lateral compartments. Control means acting between the tray and the bearing component are included which provide free posterior and anterior movement of the lateral compartment which is greater than any allowed free posterior and anterior movement of the medial compartment in relation to the tray. Thus, there is no relative free posterior movement and anterior movement of the medial compartment or some may be allowed.

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 machining assembly, including a of the disclosure novel broach design, are disclosed for preparing a femoral medullary cavity for receipt of a femoral prosthetic stem, wherein the configuration of the implantation site allows for the neutral alignment of the prothesis within the medullary cavity for improved rigid fixation of the prosthetic stem therein. Aspects of the inventive machining assembly include a novel broach comprising a proximal lateral recess that allows for initial avoidance of the greater trochanter during implantation, thereby resulting in the preparation of a neutrally aligned cavity with respect to the broach. The machining assembly also includes a guide and a second cutting instrument for removing the bone of the greater trochanter once neutral alignment between the medullary cavity and broach are achieved for the subsequent implantation of a neutrally aligned femoral prosthesis.

Abstract: An osteosynthesis device comprises a plate and screws which are screwed into bone through holes in the plate. The diameters of the holes at the top face of the plate are larger than at the bottom face of the plate. The screws have a spherical head which, when screwed in rests snugly against the wall of the screw hole with an annular contact surface. Both when the screw is located perpendicularly with respect to the plate and when located at an angle with respect to the plate, the contact surface is located above the center line of the hole depth.

Abstract: A femoral hip component for use in hip arthroplasty has a stem portion for contact with bone cement. The stem portion is formed from a biocompatible material having a surface finish of less than about four microinches. This surface is coated with a uniform layer of material selected from the group consisting of diamond-like carbon, chromium carbide, titanium nitride, titanium carbo-nitride, chromium and zirconium and a combination thereof.

Abstract: An apparatus for performing prosthesis surgery has a phantom implant component. Elements are provided for holding said phantom component accurately and stationary relative to a cavity in a bone. The phantom component has a tapered insert portion, the dimensions of which are identical to the insert portion of an implant component which is to be fitted. A method of performing prosthesis surgery is included which uses the apparatus set forth above which includes preparing an opening in a bone with cement, inserting the insert portion of the phantom component, allowing the cement to at least partially set, removing the phantom component, inspecting the cement and then inserting the implant component with the identical insert portion dimensions.

Abstract: An improved asymmetric femoral hip stem component for use in cementless hip replacement procedures is described. The stem comprises a proximal region having a novel three-dimensional configuration to allow for better fit and stability of the stem within the femoral intramedullary canal with minimal removal of strong bone therefrom. The stem further includes a twist isolated in the mid-stem region to improve fit while minimizing enlargement of the femoral canal. A distal end comprising a rotated internal slot is also described, wherein the slot reduces bending stiffness of the stem in both the coronal and sagittal planes.

Abstract: The plug is made of a plastic material and acts as a cement barrier for openings produced by an operative procedure in medullated bones. The plug is clamped between the side walls of the opening of the bone by means of elastic flanges and prevents the bone cement from escaping downwards on insertion of an intramedullary stem or upon pressurization of the bone cement.

Abstract: An articulation element for the relative positioning of fixation bars or bone pins of an external fixator includes a plurality of pairs of jaws. The jaws have on their adjacent faces grooves which form a passage intended to receive a bar or a pin. A spring is interposed between the pairs of jaws. The grooves which form the passage are positioned and arranged so as to have an external opening allowing the bar or bone pin to be snapped in by pressure on it, from the opening of the jaw into the passage, against the spring force which presses the adjacent faces of the jaws against one another. This force holds the articulation element on the bars or pins before locking of the articulation by the tightening of a clamping shaft.

Abstract: A medical implant made of polymeric material having an increased oxidation resistance is formed by a method including the steps of placing a resin powder in a sealed container. A substantial portion of the oxygen is removed from the sealed container by either a vacuum, an oxygen absorbent or by flushing with inert gas. The container is then repressurized with a gas such as nitrogen, argon, helium or neon so that long term storage may be possible. On use, the resin is transferred to a forming device which both melts and forms the resin in an oxygen reduced atmosphere to produce a polymeric raw material such as a rod or bar stock. The medical implant is then formed from this raw material annealed and sealed in an air-tight package in an oxygen reduced atmosphere. The implant is then radiation sterilized and thereafter annealed in the package for a predetermined time and temperature sufficient to form cross-links between any free radicals in neighboring polymeric chains.

Abstract: A patella milling instrument has a planar base with a fixed patellar clamping element formed thereon. A movable patellar milling element is slidably mounted on the base and is movable towards and away from the fixed clamping element. A drive element is operable between the base and the movable element for moving the movable clamping element. The drive element is actuated by a drive mechanism fixed in a handle of the device found at one end thereof and connected to a drive element which is also in the form of a ratchet element. A movable end mill type cutting element is mounted on a support arm supported by the base. The support arm is capable of movement in directions parallel to the plane of the base and is adjustable in a direction perpendicular to the base. The end mill has a drive shaft rotatably mounted in a bushing in an end of the support arm which drive shaft is rotatable by a power tool and capable of movement in a direction perpendicular to the plane of the base.

Abstract: A sealed airtight container and a method for forming the same produces an increased resistance between the seal and a flange on the container to pressure differences between the inside of the container and the outside environment. The container includes a body having a hollow interior with sidewalls, a bottom, and having a planar opening at one end. The opening in the hollow interior is surrounded by an outwardly extending flange. A multi-layer peelable cover is sealed to the flange surrounding the opening. The cover and the flange are deformed towards the bottom of the container from the plane of the opening to be sealed.

Abstract: A space correction apparatus is provided for a knee prosthesis comprising a body and two pairs of parallel runners extending on both sides of the body in a direction perpendicular to the plane of the body and of which the spacing of the front and back parts can be adjusted independently. This apparatus makes it possible to measure the spacing between the resected parts of the tibia and the femur in the extension position and to reproduce the spacing in flexion position so as to perform resections of the femur in this latter position.

Abstract: An improved surgical broach for preparing an intramedullary canal of a bone for receiving a prosthesis is described, wherein the broach comprises a plurality of cutting teeth having different configurations and placement upon the broach for optimizing cutting efficiency and speed for improved surgical ease-of-use while minimizing gap formation between the prosthesis and the intramedullary canal.

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 plate for covering a drill hole in a skull cap and for fixing a cranial bone cover comprises a plurality of vanes (16a-16e) extending radially with respect to a center (12) and slots (20a-20e) between the vanes. For receiving bone screws holes (18a-18e) are provided in the respective region of the outer periphery of the vanes.