Abstract: A prosthetic femoral implant for use in a hip joint, as a ball and socket type joint, is disclosed. The implant includes a modular neck having a variety of adjustable positions to adjust the lateral offset and version angle of the femoral implant in relation to the femur. The implant further includes a broad, full collar for providing a compression force increasing the interdigitation between the interface of the bone, implant and cement. The implant also includes a stem having a depression having a roughened porous surface for resisting the increased torsional loads placed on the implant due to the increased lateral offset and version angle. The stem further comprises three distinct zones, each zone having its own roughened surface creating a tripartite differential porosity.

Abstract: A cementless femoral hip stem component. The hip stem component includes an elongate stem, a proximal body, and a collar disposed on the proximal body and extending outward therefrom in a sideways direction to form a ledge. The proximal body defines at least a majority of a frustoconical shape. The ledge formed by the collar includes a tapered undersurface, beneath which extends the proximal body. The tapered undersurface of the ledge and the proximal body extend in different directions and thereby cooperatively define a double-flared contact surface configured to enable subsidable engagement of said double-flared contact surface with the femur at two different rates of subsidence within the femur. An abrupt, male corner is formed by the stem and the proximal body and is sufficiently abrupt to provide enhanced bone ingrowth stimulation.

Abstract: A cementless femoral hip stem component. The hip stem component includes an elongate stem, a proximal body, and a collar disposed on the proximal body and extending outward therefrom in a sideways direction to form a ledge. The proximal body defines at least a majority of a frustoconical shape. The ledge formed by the collar includes a tapered undersurface, beneath which extends the proximal body. The tapered undersurface of the ledge and the proximal body extend in different directions and thereby cooperatively define a double-flared contact surface configured to enable subsidable engagement of said double-flared contact surface with the femur at two different rates of subsidence within the femur. An abrupt, male corner is formed by the stem and the proximal body and is sufficiently abrupt to provide enhanced bone ingrowth stimulation.

Abstract: A cemented acetabular prosthesis includes a cup body having a relative thin wall (for example, 2 mm). The body has a concave surface, a convex surface, and an annular rim. A plastic liner registers into a concavity of the cup body, the liner having a wall with a liner wall thickness much greater than the cup body wall thickness and a concave surface and a convex surface that registers and fits the concave surface of the cup body. The cup body wall provides a plurality of openings. Some of the openings are bone screw receptive openings that are reinforced with an annular reinforcement that extends away from the convex surface of the cup body. Other openings are unreinforced openings that allow cement to flow from the concave to the convex side of the cup body and into the patient's acetabulum during surgery. The cup body has a peripheral buttress portion for supporting a volume of cement of the cement mantle at a peripheral interface position between the liner and the body.

Abstract: A cementless femoral hip stem component includes an elongate stem having opposing distal and proximal sections. The proximal section includes a conical stem surface which terminates in a proximal end. A collar having a conical undersurface extends laterally outward from the proximal end of the stem. The proximal conical stem portion and the conical undersurface of the collar cooperatively define a unitary double-cone contact surface to allow the collar to subsidably engage with external cortical bone in tandem with the proximal conical stem subsidably engaging with the internal femoral canal.

Abstract: A modular hip stem prosthesis including a separate and interchangeable stem piece and proximal shoulder piece. Coronal and sagittal slots are formed in a rounded distal end of the stem in a substantially right-angle orientation. A neck member extends angularly outward from the shoulder piece and is configured to receive a spherical hip ball for insertion into the hip socket. The proximal shoulder piece includes a cylindrical projection for insertion into an axial bore formed in an upper end of the stem. An annular lip is formed in side walls defining the axial bore, and a distal end of the cylindrical projection abuts the lip when it is inserted into the bore. Radial teeth are formed on a distal end of the cylindrical projection and mate with compatible teeth formed on the annular lip to thereby render the shoulder piece removably mountable onto the stem. A locking screw securely joins the shoulder piece with the stem.

Abstract: A ball and socket prosthetic joint device. A plurality of curved rigid segments are embedded within and extend out of a polymeric cushion to form a discontinuous hemispherical bearing surface for slidable engagement with a continuous hemispherical bearing surface.

Abstract: An oblong acetabular cup which includes a cavity for receiving a bearing element is provided. The plane of the opening into the cavity is skewed relative to the prosthesis' longitudinal plane so as to achieve adduction correction, anteversion correction, or both adduction and anteversion correction. In certain preferred embodiments, the prosthesis is constructed from two components which can be oriented with respect to one another to achieve different directions and amounts of anteversion correction. In some embodiments, the two components form a cusp in the outside surface of the prosthesis. Surgical instruments and surgical methods for implanting the prostheses are disclosed.

Abstract: Artificial joint prostheses are provided whose outer surfaces include a screw thread which is interrupted by porous-coated columns so as to produce an alternating pattern of threaded columns adjacent to porous-coated columns. The threaded columns provide initial mechanical fixation of the prosthesis to bone and the porous-coated columns provide long-term fixation through bone ingrowth.

Abstract: Artificial joint prostheses are provided whose outer surfaces include a screw thread which is interrupted by porous-coated columns so as to produce an alternating pattern of threaded columns adjacent to porous-coated columns. The threaded columns provide initial mechanical fixation of the prosthesis to bone and the porous-coated columns provide long-term fixation through bone ingrowth.