Abstract: A polyurethane casting tape with controlled tack is disclosed. The tackiness of the polyurethane is controlled by the addition of combinations of Kurrol salts, potassium metaphosphate and a sodium salt.

Abstract: A self-locking orthopaedic clamp includes first and second jaws, each jaw having a work engaging surface and a handle comprising first and second actuation members, each actuation member having a first end proximate to the first and second jaws and a second opposed end, and the second actuation member being rigidly coupled to and integral with the second jaw. A four-bar linkage connects the first and second jaws and the first and second actuation members. The design of the clamp and the four-bar linkage is such that the clamp is self-locking. The clamp may be configured for use in a variety of orthopaedic procedures, but it is especially useful for clamping a prosthesis to a resected natural patella.

Abstract: An acetabular prosthesis has a shell component that is implantable within bone and a liner component that is matable to the shell by a locking member disposed with the shell component. The shell has a generally convex bone engaging outer surface and a generally concave inner surface. A groove is formed in the inner surface of the shell and extends about at least a portion of the inner circumference of the shell. The liner has an inner concave surface and an outer, convex surface with a shape complementary to and matable within the inner surface of the shell. One or more deformable tabs are formed on the locking member, adapted for securing the liner within the shell. The liner may be joined to the shell by press fitting the two components together such that the locking members engages one or more positive surface ridges on the liner.

Abstract: A guide and cutting system is provided that is effective to accurately and efficiently resect a bone, such as the femur, to accept joint prosthesis components. In particular, the guide and cutting system of the invention is useful to resect the distal end of the femur to form an intercondylar notch therein that will accept a posterior stabilized femoral component in the prosthesis. The system includes a guide component that with a square bushing is attachable to bone or to a separate guide assembly. A cutting device that includes a rotatable cutting device disposed inside a non-rotatable housing is insertable within the guide bushing to effect bone resection.

Abstract: An implantable pressure measurement device is effective to measure a physiological pressure, which pressure can be ascertained by external imaging of the device. In one embodiment, a predetermined amount of a fluid is sealed in a flexible member which is disposed in a housing. A position indicating member is coupled to one end of the flexible member. The fluid expands and contracts the flexible member in response to external pressure changes. A physiological pressure is determined by ascertaining the relative location of the position indicating member on the housing. An external imaging system is used to view scale markings located on the position indicating member and the housing. In another embodiment, an elongate member is axially movable within a housing. A sealing member seals an amount of air in a portion of the housing and is sealably engaged with one end of the elongate member. A physiological pressure is determined using an imaging system to determine the position of the elongate member.

Abstract: A joint prosthesis comprising a metallic body having a plurality of negative surface features such as through-slots, deep grooves, tunnels or pits, or valleys defined between projecting fingers or flutes. The metallic body constitutes the structural component of the prosthesis, such as a shell, plate or stem. A second part attaches to and extends the body to provide both a fit and a change in the initial stiffness. The second part provides a time-evolving structural coupling, such that the prosthesis initially fits the patient's remnant bone to provide rigid fixation, while the mechanical properties shift with time in vivo to change its contact or loading characteristics. In one embodiment a femoral stem joint prosthesis is modular and the first, or structural component, accommodates bio-absorbable second components of varying geometries and dimensions which fit a range of bore sizes, and achieve different stiffnesses or strengths affecting load or strain distribution.

Abstract: An acetabular prosthesis has an oblong geometry in which its dimensions in a first axis exceed those in a second axis that is normal to the first axis. The prosthesis has a superior, bone engaging surface with primary and secondary partial spheres that are merged together. The opposed inferior surface of the prosthesis includes at least one hemispherical cavity that is formed within the primary partial sphere. The primary partial sphere has dimensions that exceed the secondary partial sphere by less than or equal to about 5%.

Abstract: A cerebrospinal fluid (CSF) shunt valve includes a valve housing and a substantially flat stabilizing member that has a width substantially greater than that of the valve housing. The shunt valve is adapted for surgical implantation under the scalp of a patient to drain excess CSF from the brain. The stabilizing member rests on the skull of a patient and the stabilizing member is effective to prevent rotation of the shunt valve about a longitudinal axis thereof. The shunt valve includes a pressure adjustment mechanism disposed within the housing, for adjusting a threshold pressure at which fluid may flow through the shunt valve.

Abstract: A system for reaming a cavity in bone for implantation of a prosthetic component, such as an oblong acetabular cup having an outer surface formed by adjacent hemispheres. In one embodiment, the reaming system is useful to form a second cavity in relation to an already formed first cavity. The reaming system includes an instrument with an elongate handle and a drive member coupled to a bearing plate with a locator member removably and replaceably mountable to the bearing plate. The drive member has a distal reamer mating end and a proximal end for coupling with a drill mechanism. The distal reamer mating end is axially movable toward and away from the bearing plate to ream the cavity corresponding to the secondary hemisphere of the acetabular cup to be implanted. In another embodiment, the reaming system includes a plurality of reamers each having different outer dimensions and being matable to the drive member.

Abstract: An implantable article includes a textured bone engaging surface having a surface texture pattern formed by a plurality of furrows separated by ridges that are integral with the base material from which the article is formed. The furrows are formed by ablating in the surface a series of intersecting holes. The side walls of the furrows have scalloped edges. The ablating energy can be applied by techniques such as laser ablation and hydrojet ablation.

Abstract: An investment casting shell is made by providing an investment casting pattern that defines a cavity and filling the cavity with a fluid. The fluid is sealed within the cavity and a ceramic material is applied to the exterior of the pattern. The ceramic-encased pattern is heated and the pattern and fluid are removed from the ceramic.

Abstract: Methods are provided for producing investment cast articles, such as orthopedic implants or portions thereof, having at least a partially textured surface that is formed during casting of the article. In an exemplary method, a textured metal casting is produced by creating a heat destructible pattern and spraying the pattern with a texturing material to cause the texturing material to form a textured surface on at least a portion of the pattern. In another embodiment, a textured template is pressed against a heat softenable pattern to provide a textured pattern. With respect to each of these methods, a shell is the created around the textured pattern form a mold, and the pattern is removed from the shell. Molten metal is introduced into the mold and allowed to harden, after which the mold is removed. In yet another embodiment a textured pattern for investment casting is provided by creating a textured model and enveloping it with a resilient material to create a resilient mold.

Abstract: A joint prosthesis having two mutually articulating components that are made of a metal alloy. One of the components is made of an alloy having a low carbon content (0.03 to 0.10 wt. %) and the other component is made of an alloy having a high carbon content (0.18 to 0.35 wt. %). The articulating components may be, for example, a hip head prosthesis and an acetabular cup prosthesis.

Abstract: An implantable article having on at least a portion of its exterior surface an integral, as-cast macrotextured surface with macropores having undercut edge profiles. A complex macrotextured surface is provided by forming a casting mold so that the mold has complementary macrotextured surface features formed by three-dimensional printing techniques, and casting a molten metal within or in contact with the casting mold to form the implantable article. In a hybrid process, one or more printed surface mold plates are attached by hand, or in a wax molding process, to a simpler wax preform, and an investment is made in which the plates are incorporated into the investment mold. A casting is then made, with each preform yielding one cast article, and the incorporated plate forming the desired surface macrotexture on a region of the cast article.

Abstract: A femoral head trial adaptor for converting a shell trial to a head trial includes a barrel member having an outer surface and an inner surface defining a cavity for receiving a femoral neck trial. A circumferential flange portion is located on the outer surface of the barrel member. A resilient connecting member disposed on the circumferential flange has a nominal first diameter compressible to a smaller second diameter in response to a force and returnable to the first diameter in the absence of the force for securing the trial adaptor to a shell trial. The flange may be located at a predetermined position along the outer surface of the barrel member so as to simulate a neck trial of a given length.

Abstract: A calcar trial includes a stem having a proximal end and a distal end, and a body. The body is engaged with the stem near the proximal end of the stem and is slidable with respect to the stem. A locking mechanism inhibits movement of the body with respect to the stem when desired. A collar extends radially outward from the stem to surround a portion of the body. The body and stem are configured so that the diameter of the calcar trial at a point between the collar and the distal end of the stem increases as the body is moved toward the distal end of the stem and decreases as the body is moved away from the distal end of the stem. The proximal end of the stem can include opposed notches that are egagable by a forked tool. A curved distal stem portion can be secured to the distal end of the stem.

Abstract: An acetabular trial insert is provided in which the appropriate anteversion angle of the acetabular cup of a hip prosthesis may be determined automatically by placing an inner cup within an outer cup and providing a mechanism which will hold the inner cup in position after the trial has been reduced and the hip rotated through an intended range of motion.

Abstract: A cast saw for removing hard orthopaedic bandages, for example formed of plaster is disclosed. The cast saw is a unitary device containing a rechargeable battery pack in a removable filter form collection chamber. A shroud covers at least a portion of the saw blade and such shroud is movable by the cutting operation from the interference of the casting material as the blade is received within the casting material while cutting through such casting material. A dust channel is formed within the housing and dust and debris caused by the cutting operation is pulled through such dust channel by the forces applied by impeller rotated by an electric motor received within the housing. A pressure sensitive switch is supplied which senses an increase in force on the saw blade and increases the current supplied to the motor proportionally in order to provide additional torque to the motor.

Abstract: A bistable cement restrictor is provided for creating a fixed obstruction at any selected point within a long bone, particularly at points beyond the isthmus of the bone. An exemplary cement restrictor includes a body having a first end and a second end. One or more bistable fins extend radially from the body and are movable from a first stable state to a stable state either mechanically or thermally. In the first stable state, the cement restrictor is narrower than in the second stable state. While the cement restrictor is readily transitionable from the first stable state to the second stable state, the transition can be irreversible.

Abstract: A modular prosthesis includes a component having a superior surface and an inferior surface. An elongate aperture having a major axis and a minor axis is defined in the component and a bolt shank is insertable through the elongate aperture in the component to extend beyond the inferior surface thereof. Means are provided for selectably positioning the bolt at one of a number of selected points along the major axis of the elongate aperture. In an illustrated embodiment, the means for positioning the bolt includes more than one seat for a bolt head about the aperture. In another embodiment, the prosthesis includes an adapter having a first end defining a cavity for receiving the shank of the bolt extending from the inferior surface. The adapter includes teeth on the first end that are engagable with at least one or more teeth near the aperture in the component on its inferior surface to fix the cavity, and thus the bolt, at a selected point along the major axis of the aperture.