Abstract: A modular prosthesis is provided having a first and second prosthesis component and a locking nut. The first prosthesis component is configured to include a mating surface and a threaded shaft extending from the mating surface. The locking nut is formed to include a distal end having a shaped surface. The second prosthesis component is configured to include a mating surface, a nut-receiving cavity and a bore. The mating surface of the second prosthesis component is configured to mate with the mating surface of the first prosthesis component. The nut-receiving cavity is configured to receive the locking nut therein and to have a shaped bottom wall configured to engage the shaped surface of the locking nut. The bore communicates with the nut-receiving cavity through the shaped bottom wall and the mating surface and is sized to receive the threaded shaft therethrough.

Abstract: A prosthetic trial for a joint prosthesis includes a stem having a proximal section and a distal section for implantation in a bone. A body includes a channel receiving at least the proximal section of the stem. A locking mechanism is at least partially disposed within the body. The locking mechanism is biased into a locking position in which the mechanism locks the stem within the first channel of the body. The locking mechanism is accessible outside said body to be pulled into a releasing position to unlock the stem from the body.

Abstract: A prosthetic trial for a joint prosthesis includes a stem having a proximal section and a distal section for implantation in a bone. A body includes a channel receiving at least the proximal section of the stem. A locking mechanism is at least partially disposed within the body. The locking mechanism is biased into a locking position in which the mechanism locks the stem within the first channel of the body. The locking mechanism is accessible outside said body to be pulled into a releasing position to unlock the stem from the body.

Abstract: A modular prosthesis is provided having a first and second prosthesis component and a locking nut. The first prosthesis component is configured to include a mating surface and a threaded shaft extending from the mating surface. The locking nut is formed to include a distal end having a shaped surface. The second prosthesis component is configured to include a mating surface, a nut-receiving cavity and a bore. The mating surface of the second prosthesis component is configured to mate with the mating surface of the first prosthesis component. The nut-receiving cavity is configured to receive the locking nut therein and to have a shaped bottom wall configured to engage the shaped surface of the locking nut. The bore communicates with the nut-receiving cavity through the shaped bottom wall and the mating surface and is sized to receive the threaded shaft therethrough.

Abstract: A joint prosthetic component that includes first and second arms, and a joint member interposed therebetween. The joint member is configured to permit flexion motion between the first and second arms, and includes a first concave surface and a second concave surface. The first concave surface has a plurality of arcuate portions defined therein. The first and second concave surfaces are located on opposing sides of the joint member.

Abstract: A system of reconstruction for a spinal joint allows adjacent vertebrae to move relative to each other in a generally pivotal manner and in a limited sliding manner in either or both of the anterior-posterior direction and the medial-lateral direction. The system includes base components and a middle component. The base components are for attachment to adjacent vertebrae and support a pivoting cooperative engagement of a concave or cup-shaped component with a convex or dome-shaped component.

Abstract: A vertebral plate system and associated method minimizes the number of required multiple configurations and sizes of hardware on hand during surgery for repair, stabilization or fusion of bone segments. A novel aspect of the invention is a resilient split ring that cooperates with angled contact surfaces in a plate for allowing convenient and fast dynamic locking between the plate and a bone screw. In another aspect of the present invention, a screw or similarly elongated fastener having a generally spherical or part-spherical head with a section of helical threads is configured in a generally horizontal band and positioned around a maximum-diameter section of the head. The screw is loosely retained to a first structure by a snap-ring formed from a ring of elastic material having a slot cut so that the ring is a “C” ring. The ring is seated on an annular shoulder formed in a through-hole in the first structure.

Abstract: A prosthetic trial for a joint prosthesis includes a stem having a proximal section and a distal section for implantation in a bone. A body includes a channel receiving at least the proximal section of the stem. A locking mechanism is at least partially disposed within the body. The locking mechanism is biased into a locking position in which the mechanism locks the stem within the first channel of the body. The locking mechanism is accessible outside said body to be pulled into a releasing position to unlock the stem from the body.

Abstract: A joint prosthetic component that includes first and second arms, and a joint member interposed therebetween. The joint member is configured to permit flexion motion between the first and second arms, and includes a first concave surface and a second concave surface. The first concave surface has a plurality of arcuate portions defined therein. The first and second concave surfaces are located on opposing sides of the joint member.

Abstract: An implantable prosthetic component, such as a femoral stem, includes a plurality of bone-engaging ribs which are configured so as to engage dense cancellous bone upon implantation. The ribs have a geometry and spacing for achieving optimal fixation in the medullary canal of the femur by engaging predetermined dense cancellous bone.

Abstract: A prosthetic joint system includes a body having at least one aperture into which an elongate sleeve component is engageable. A screw for securing the body to bone is insertable into the bone via a bore in the sleeve. The bore has a length that is sufficient to accommodate movement of the screw as the prosthesis subsides over time. More particularly, the sleeve allows the screw head to move longitudinally such that the screw is prevented from damaging an inner member of the prosthesis system that provides an articulation surface for a corresponding prosthetic joint component. In one embodiment, a prosthesis system includes an acetabular cup for a prosthetic hip joint.

Abstract: An articulating prosthesis includes a cup having a shell and a liner and at least one resilient locking element. The shell has a spherical outer surface that may be adapted to articulate with an acetabulum and the liner has a spherical inner surface that forms an articulation surface for the spherical head of a stem member. The resilient locking member extends inward toward a longitudinal axis of the cup and at least partially in a superior direction. The resilient locking element defines a nominal first diameter expandable to a larger second diameter in response to a force and is returnable to the first diameter in the absence of the force for securing the head of a stem prosthesis member.

Abstract: An acetabular cup having an outer surface elongated in a superior/lateral direction is effective to anatomically transfer load to the acetabulum and reduce the likelihood of bone fracture during implantation into the acetabulum. The outer surface has a first portion defined by a first radius and a second portion defined by a second radius. The second radius is offset from the first radius in superior and lateral directions to elongate the outer surface of the acetabular cup.

Abstract: A sleeve component for engagement with a prosthetic component, such as a revision femoral component, compensates for bone loss and/or anatomical anomalies. In one embodiment, the sleeve includes a compensating region which provides an eccentric outer surface for offsetting proximal, posterior bone loss in the patient's femur. The sleeve has a bore through which the stem of a femoral component is insertable. The inner walls of the bore taper so as to complement a proximal outer surface of the stem when the sleeve abuts a shoulder portion of the femoral component. In one embodiment, the compensating region is defined by a radius which is offset from the longitudinal axis of the sleeve. In another embodiment, the compensating region is defined by a radius extending from the longitudinal axis and having an increased length.

Abstract: An acetabular cup having an outer surface with a first set of steps formed in a first direction and a second set of steps formed in a different, second direction is effective to provide positional stability and enhanced load transfer after implantation in the acetabulum. The stepped outer surface of the acetabular cup provides a significant increase in effective surface area. The multi-directional first and second steps convert shear loads to compressive loads in their respective directions, resulting in enhanced fixation of the cup.

Abstract: An orthopedic reaming instrument has an elongate member and a reaming member disposed on a distal end of the elongate member. The reaming member includes a distal apical region in the form of a partial sphere having an arc of less than 180.degree. and a proximal cylindrical region. An acetabular instrumentation system has an acetabular prosthesis in the form of a partial sphere having an arc of less than or equal to 180.degree. and an acetabular reamer which includes a distal apical region in the form of a partial sphere having an arc that is less than the arc of the prosthesis.

Abstract: A tamp system includes a plurality of tamps, each of which includes an elongated body having a stepped outer surface. The body has a diameter and a longitudinal axis, wherein the diameter decreases from a proximal end to a distal end thereof. The stepped outer surface includes a plurality of steps each having a distal-facing surface and a side-facing surface. Each tamp is adapted for compacting morsellized bone matter in a canal in a bone. The compacted bone matter can be used to resize the canal for a new prosthesis in a prosthesis revision surgery.

Abstract: A spacer includes a body having a first end, a second end, and an aperture open at the first end and at the second end. The spacer can be an element of a prosthetic joint component system that further includes a cement injection nozzle insertable through the aperture in the spacer and a sleeve disposable around at least a portion of the nozzle.

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.