Abstract: A knee prosthesis assembly can comprise a patella prosthesis adapted to be secured to a natural patella portion having an anterior surface and a posterior surface. An articulating portion can have a posteriorly facing portion and an anteriorly facing portion. The posteriorly facing portion can have a spherical articular surface. A porous portion can have a first portion that engages the anteriorly facing portion and a second portion that engages the natural patella portion. A fastener can pass entirely through a passage formed at a centermost portion of the natural patella portion from the anterior surface to the posterior surface and into a bore defined in the centermost portion of the porous portion to securably engage the porous portion.

Abstract: A guide for cutting a bone comprising an anterior portion and a distal portion orientated at about a right angle to the anterior portion. The distal portion includes a guiding side, a distal surface at the guiding side, a box-cut shaped opening defined by the guiding side, a plurality of first cutting surfaces disposed at the guiding side at an acute angle relative to the distal surface of the guiding side operable to guide a cutting device to the bone to form chamfer cuts in the bone, and a second cutting surface disposed at the guiding side at least about a right angle to the distal surface operable to guide a cutting device to the bone to form a posterior cut in the bone.

Abstract: A bone-cutting apparatus and associated method and system. In one embodiment, the apparatus includes a guide removably attachable to a bone, and a rotatable mill coupled to the guide. The guide has a box-cut opening and the mill is pivotable within the opening. In one embodiment, the mill is laterally adjustable relative to the opening.

Abstract: A guide for cutting a bone comprising an anterior portion and a distal portion orientated at about a right angle to the anterior portion. The distal portion includes a guiding side, a distal surface at the guiding side, a box-cut shaped opening defined by the guiding side, a plurality of first cutting surfaces disposed at the guiding side at an acute angle relative to the distal surface of the guiding side operable to guide a cutting device to the bone to form chamfer cuts in the bone, and a second cutting surface disposed at the guiding side at least about a right angle to the distal surface operable to guide a cutting device to the bone to form a posterior cut in the bone.

Abstract: A guide for cutting a bone comprising an anterior portion and a distal portion orientated at about a right angle to the anterior portion. The distal portion includes a guiding side, a distal surface at the guiding side, a box-cut shaped opening defined by the guiding side, a plurality of first cutting surfaces disposed at the guiding side at an acute angle relative to the distal surface of the guiding side operable to guide a cutting device to the bone to form chamfer cuts in the bone, and a second cutting surface disposed at the guiding side at at least about a right angle to the distal surface operable to guide a cutting device to the bone to form a posterior cut in the bone.

Abstract: A knee prosthesis assembly can comprise a patella prosthesis adapted to be secured to a natural patella portion having an anterior surface and a posterior surface. An articulating portion can have a posteriorly facing portion and an anteriorly facing portion. The posteriorly facing portion can have a spherical articular surface. A porous portion can have a first portion that engages the anteriorly facing portion and a second portion that engages the natural patella portion. A fastener can pass entirely through a passage formed at a centermost portion of the natural patella portion from the anterior surface to the posterior surface and into a bore defined in the centermost portion of the porous portion to securably engage the porous portion.

Abstract: A bone-cutting apparatus and associated method and system. In one embodiment, the apparatus includes a guide removably attachable to a bone, and a rotatable mill coupled to the guide. The guide has a box-cut opening and the mill is pivotable within the opening. In one embodiment, the mill is laterally adjustable relative to the opening.

Abstract: A bone-cutting apparatus and associated method and system. In one embodiment, the apparatus includes a guide removably attachable to a bone, and a rotatable mill coupled to the guide. The guide has a box-cut opening and the mill is pivotable within the opening. In one embodiment, the mill is laterally adjustable relative to the opening.

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: The distribution of short, fine, reinforcing fibers homogeneously throughout surgical bone cement is accomplished by adding the fibers in the form of bundles of several hundred fibers with the fibers bonded to each other with an adhesive binder that is soluble in the liquid monomer component of the bone cement. The fiber bundles are either premixed with the powdery polymer bead component of the bone cement followed by addition of the liquid monomer or the polymer and liquid are premixed into a viscous liquid and the fiber bundles are gradually added with stirring to the viscous liquid. In either case, as the adhesive binder dissolves in the liquid monomer the individual fibers are freed and continued stirring mixes the fibers homogeneously throughout the cement mass.