Abstract: A method for performing shoulder arthroplasty or hemiarthroplasty is provided. The method includes generating navigational reference information relating to position and orientation of a body part forming at least a portion of the shoulder joint. The reference information may be stored in a computer. Navigational references are attached to the body part and an object. Information is received regarding the position and orientation of the object with respect to the body part and the object is navigated according to this information. The body part may be modified using the object and the modification may be displayed on a monitor associated with the computer. The navigational references may be used to track a shoulder arthroplasty trial component. Information is received regarding the position and orientation of the trial component with respect to the body part. This information is used to navigate the trial component to the body part.

Abstract: A method of resecting distal and anterior portions of a distal portion of a femur for a bicompartmental prosthesis is provided. The method includes generating a geometric representation of the distal portion of the femur. A virtual anterior resection plane is calculated at a predetermined depth and is oriented at a predetermined angle relative to the femur. The method identifies a distal-most point of a lateral portion of the virtual anterior resection plane and an AP line. A varus/valgus angle and an anterior-posterior distance are calculated. Anterior and distal resection guides are navigated according to the parameters calculated from the method.

Abstract: Instrumentation, systems, and processes for tracking anatomy, instrumentation, trial implants, implants, and references, and rendering images and data related to them in connection with surgical operations, for example total knee arthroplasties (“TKA”). These instrumentation, systems, and processes are accomplished by using a computer to intraoperatively obtain images of body parts and to register, navigate, and track surgical instruments. Disclosed in this document are also alignment modules and other structures and processes which allow for coarse and fine alignment of instrumentation and other devices relative to bone for use in connection with the tracking systems of the present invention.

Abstract: A stem extension for surgical implants such as tibial or femoral knee implants. The stem extension is interposed between the stem and its load bearing component (i.e., tibial tray or condylar component) and angularly orients the attached stem relative to the load bearing component to facilitate positioning of the stem in the bone canal and alignment of the load bearing component with the mechanical axis of the leg. The extension includes a female taper that engages the load bearing component. The extension also includes a male taper having a longitudinal axis oriented at an angle relative to the longitudinal axis of the female taper. Engagement of the male taper with the stem thereby orients the stem at an angle relative to the longitudinal axis of the load bearing component.

Abstract: Systems and processes for tracking anatomy, instrumentation, trial implants, implants, and references, and rendering images and data related to them in connection with surgical operations, for example total knee arthroplasties (“TKA”). These systems and processes are accomplished by using a computer to intraoperatively obtain images of body parts and to register, navigate, and track surgical instruments.

Abstract: Artificial implants having reduced area to provide reduced wear are provided. The reduced area is particularly located at areas where greatest wear is exhibited. In a particular embodiment of a mobile bearing knee implant, the area is reduced on the mobile bearing insert underside, where it contacts a tibial component. The reduced area may be any shape of indentations, for example, grooves, dimples, straight patterns, curved patterns, crossing patterns, holes, channels or slots. The indentations may be various sizes, and have been found to be particularly effective if covering about 10% to about 20% of the insert at depths between about 1-2 mm.

Abstract: Instrumentation, systems, and processes for tracking anatomy, instrumentation, trial implants, implants, and references, and rendering images and data related to them in connection with surgical operations, for example total knee arthroplasties (“TKA”). These instrumentation, systems, and processes are accomplished by using a computer to intraoperatively obtain images of body parts and to register, navigate, and track surgical instruments. Disclosed in this document are also alignment modules and other structures and processes which allow for coarse and fine alignment of instrumentation and other devices relative to bone for use in connection with the tracking systems of the present invention.

Abstract: A stem extension for surgical implants such as tibial or femoral knee implants. The stem extension is interposed between the stem and its load bearing component (i.e., tibial tray or condylar component) and angularly orients the attached stem relative to the load bearing component to facilitate positioning of the stem in the bone canal and alignment of the load bearing component with the mechanical axis of the leg. The extension includes a female taper that engages the load bearing component. The extension also includes a male taper having a longitudinal axis oriented at an angle relative to the longitudinal axis of the female taper. Engagement of the male taper with the stem thereby orients the stem at an angle relative to the longitudinal axis of the load bearing component.

Abstract: Artificial implants having reduced area to provide reduced wear are provided. The reduced area is particularly located at areas where greatest wear is exhibited. In a particular embodiment of a mobile bearing knee implant, the area is reduced on the mobile bearing insert underside, where it contacts a tibial component. The reduced area may be any shape of indentations, for example, grooves, dimples, straight patterns, curved patterns, crossing patterns, holes, channels or slots. The indentations may be various sizes, and have been found to be particularly effective if covering about 10% to about 20% of the insert at depths between about 1-2 mm.

Abstract: A mobile bearing knee prosthesis enables a surgeon to convert a mobile bearing insert having articular surfaces, supported by a tibial base plate or tray from a rotating and translating prosthesis to one that rotates only. This conversion is accomplished with a fastener or locking member that connects through an opening in the insert to the tibial base plate. This prosthesis can be used as part of a total knee surgery when the surgeon chooses to use a prosthesis that incorporates a movable articular surface. In one embodiment, a projecting portion extends proximally from the insert and cooperates with a cam on the femoral component. The projecting portion can be a post extending up from the proximal surface of the insert and the femoral component includes an intercondylar surface that may contact the post to constrain the relative motion between the femoral component and the insert.