Abstract: The stem is cast about an irregular plug body, which is then removed, leaving a wall thickness that satisfies the opposing constraints of high strength and relatively low stiffness. The plug narrows the prosthesis wall thickness in upper regions thereof and strengthens the wall about regions of recessed or discontinuous features, or high load coupling, to assure that the stem has adequate strength in regions of high strain, while effectively coupling strain to surrounding bone. The prosthesis is produced in a range of sizes, and plugs or entire molds for casting the hollow body are readily made and modified by a three-dimensional printing mold fabrication technique.

Abstract: A joint prosthesis component system allows an inferior component of a prosthesis system to be offset from a superior component of the system. In one embodiment the joint prothesis component system comprises a tibial tray having an offset tibial stem. An adapter element connects between the tibial tray and tibial stem to provide the desired degree of offset and the orientation of the offset. The adapter element is constructed such that a longitudinal axis extending through a first end thereof is offset from a longitudinal axis extending through a second end thereof.

Abstract: A modular femoral trial system is provided having femoral trial bases of various sizes and adapters which may be used to convert the base from a cruciate retaining trial to a cruciate sacrificing trial or a trial for an implant with increased built in stability.

Abstract: A modular joint prosthesis system includes an articulation component having a bone engaging surface and an opposed articulation surface. Fixation peg members and/or augmentation components are selectively attachable to the bone engaging surface of the articulation component. The articulation component may be a cruciate sacrificing femoral component of a knee prosthesis.

Abstract: A method of making a custom, bioimplantable article, such as a joint prosthesis component, is provided using computer aided design, rapid prototyping, and investment casting techniques. The method includes the creation of a data file, using computer aided design (CAD) techniques, that defines a negative or a shell of a portion of a bioimplantable article that is custom configured for a specific arthroplasty patient. The data file for the shell of the custom portion of the bioimplantable article is accessed by a rapid prototyping machine, such as a three-dimensional printer, to create a mold that corresponds to the shell. The mold, generally a heat-resistant ceramic, is positioned relative to an existing, non-custom representation of a bioimplantable article to define a hybrid component. A heat-resistant shell is formed around the hybrid component and the non-custom representation of a bioimplantable article is removed from the shell using heat.

Abstract: A modular joint prosthesis system includes an articulation member, such as a cruciate retaining femoral component of a knee joint prosthesis, having a superior bone engaging surface, an inferior articulation surface and one or more fixation pegs extending from the superior surface. An augmentation block mounts on the superior surface of the articulation member and has an aperture surrounding a respective fixation peg. The system further includes a compression collet seated between the aperture of the augmentation block and the fixation peg. In assembly, a securement device mounted over the fixation peg compresses the compression collet so as to engage the fixation peg and maintain the augmentation block on the articulation member.

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 created around the textured pattern to 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.

Abstract: An instrument for orthopedic surgery comprising a block or cutting guide having a recess, and at least one locking device located on the cutting guide. The locking device is selectively movable between a first position in which a portion of the locking device covers a portion of the recess and a second position in which the recess is unobstructed. A bushing having a portion adapted to removably and replaceably mate with the recess on the cutting guide is also disclosed. The instrument is particularly useful for distal femoral augmentation in knee revision surgery.

Abstract: The investment casting process utilizes an investment assembly that includes one or more vents in each casting mold. Vents facilitate the extraction of the pattern material while preventing expansion of the pattern material to the extent that mold fracture or cracking results. The vents can be formed by incorporating within the patterns of articles to be cast one or more protrusions that cause the pattern to deviate from the size and shape of the article to be cast. After assembly of one or more patterns to a riser to form a cluster, the cluster is coated with a refractory material and the refractory material is removed from the protrusions either before the refractory dries or after the refractory dries, thus producing the vents.

Abstract: A quick-release alignment handle system is provided including a quick release alignment handle with an attachable, releasable locking mechanism for attaching the handle to a tibial tray trial component of a surgical instrument system for implanting artificial knees.

Abstract: A detachable cap for use in determining the location of the center of the imageable portion of a fiducial marker is disclosed. The lower portion of the cap has three arms and a boss for providing a detachable connection with an implanted base portion to which an imaging marker can be attached. The upper portion of the cap includes a divot--like depression that is configured to mate with a ball whose center can be determined. The ball, marker, and divot are configured so that the center of the ball, when mated to the divot, is coincident with the center of the marker when it is attached to the base in place of the cap. Knowledge of the location of the center of the ball when it is brought into engagement with the divot of the cap can be used to determine the location of the center of the marker when it is attached to the base.

Abstract: An acetabular cup system is provided in which an insert or liner may be selected from a plurality of types of inserts to be used with an acetabular shell. One insert may be oriented after it is removably inserted into the acetabular shell. After an orientation is selected, it may be permanently fixed by pins. The other insert includes a snap-in ring that allows the insert to be snapped into position with the shell after its orientation is selected. The snap-in insert and ring are removable from the shell using a device for removing such snap-in insert and ring.

Abstract: The invention is directed to orthopedic casting tapes including an open mesh fibrous tape coated with a hardenable liquid resin, preferably a water activatable resin, that permits shaping and curing of the tape to provide a hardened cast. The fibrous tape is a knit tape is formed primarily or entirely of unbulked, continuous polymeric filaments and elastic filaments. A plurality of continuous filament courses extend generally transverse to the plurality of wales and are present in the fibrous tape in an amount of at least 15 courses per linear inch of tape, measured in a relaxed state. The wales are present in the fibrous tape in an amount sufficient to provide at least about 275 openings per square inch. The casting tape has an extensibility of at least about 5 percent. The orthopedic casting tapes of the invention cure rapidly despite their fine mesh/high mesh content structure and normally are set within 3-5 minutes following application.

Abstract: A bone prosthesis has a stem with a hollow interior and an external surface that allows wedging contact with surrounding bone while transferring strain at a level comparable to that of natural bone. The stem is cast about an irregular plug body, which is then removed, leaving a wall thickness that satisfies the opposing constraints of high strength and relatively low stiffness. The plug narrows the prosthesis wall thickness in upper regions thereof and strengthens the wall about regions of recessed or discontinuous features, or high load coupling, to assure that the stem has adequate strength in regions of high strain, while effectively coupling strain to surrounding bone. The prosthesis is produced in a range of sizes, and plugs or entire molds for casting the hollow body are readily made and modified by a three-dimensional printing mold fabrication technique.

Abstract: A printed orthopaedic casting bandage is disclosed having a bandage substrate made of at least 50% fibers having a Young's Modulus in excess of 8.times.10.sup.6 psi. The fibers, in particular, are glass fibers and carbon fibers. The printing substance is a plastisol-based printing agent, and the printed substrate is covered with a water-activatable hardening resin such as a polyurethane prepolymer of polyol and isocyanate.

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: A bone fixation device such as a screw, pin, staple, cable or anchor has a microtextured contact surface to enhance installation or gripping characteristics, preferably by providing directional or anisotropic engagement. A surface texture comprised of patterned microfeatures imparts a roughness or actual mechanical engagement that prevents loosening. In different embodiments the features resemble an array of microbumps or pyramids, or anisotropic features such as rasp teeth, shingles, or slanted cantilevered fiber/rods. The use of microbumps present a smaller surface area when moving, while providing full area contact after the surfaces have relaxed or decompressed; installation may be effected with low force, while high static or resting friction prevents disengagement.

Abstract: An implantable bone prosthesis includes portions of two different materials which interfit with each other to form a unitary article having hard wear surface portions and strong, stiff portions for structural support. These portions are preferably formed of ceramic and of metal, respectively. The prosthesis is formed by making a multiply connected ceramic wear surface element having openings or passages therethrough, and casting the remainder of the prosthesis extending in the openings to form a mating or dendritic support or a frame interdigitated and interlocked with the ceramic wear surface. The frame may be shaped so that it contracts along a direction of shrinkage, as the casting cools, without binding against the ceramic body. In a spherical shell, such as used for the weight-bearing acetabular shell or ball joint of a hip, this is achieved with short, radially-directed interlock elements.

Abstract: An implantable article having on at least a portion of its exterior surface an integral, as-cast macrotextured surface having pores with undercut edge profiles is provided. The integral, as-cast macrotextured surface is able to be formed on the implantable articles by a modified casting process. As part of a casting process, positive models of the articles to be cast, or parts thereof, are formed by stereolithographic techniques. Cavities or molds, representing negative images of the articles to be cast, are then formed by encasing one or more models in a refractory material. The positive models are then extracted by heating and thus melting the material from which they are made. Thereafter, molten casting material can be poured into the resulting mold to obtain the implantable articles.

Abstract: A patellar component is provided for fixation to a patella and a total knee arthroplasty surgical procedure in which multiple surfaces are provided on an outer ring on the inferior surface of the patellar component to provide multi-directional load bearing surfaces available to resist loosening of the patellar component and which requires minimal bone removal for implantation.