Abstract: A stemless implant for shoulder arthroplasty includes a body having a proximal portion, distal portion, and an outer surface. A cylindrical extrusion is substantially perpendicular to and adjacent the proximal portion. At least a portion of the outer surface is configured to contact bone, the outer bone contacting surface comprising a concave taper. The stemless implant can be sized and shaped for insertion into a metaphysis of a humerus bone without penetrating a diaphysis of the humerus bone. The implant optionally comprises a medial fin, a lateral fin, an anterior fin, and a posterior fin. The medial fin and lateral fin may be thicker than the anterior fin. The fins may taper from the proximal portion to the distal portion.

Abstract: A stemless implant for shoulder arthroplasty includes a body having a proximal portion, distal portion, and an outer surface. A cylindrical extrusion is substantially perpendicular to and adjacent the proximal portion. At least a portion of the outer surface is configured to contact bone, the outer bone contacting surface comprising a concave taper. The stemless implant can be sized and shaped for insertion into a metaphysis of a humerus bone without penetrating a diaphysis of the humerus bone. The implant optionally comprises a medial fin, a lateral fin, an anterior fin, and a posterior fin. The medial fin and lateral fin may be thicker than the anterior fin. The fins may taper from the proximal portion to the distal portion.

Abstract: An implant for shoulder arthroplasty includes a stem and optionally a head component or a cup component. The stem is sized and shaped to fit into an intramedullary canal of the humerus. The proximal portion of the stem has a concave taper and the distal portion of the stem has a taper. The distal taper includes an anterior-posterior taper and a medial-lateral taper. The shape of the stem loads the metaphysis of the humerus with a greater load than the load applied to the diaphysis of the humerus.

Abstract: An implant for shoulder arthroplasty includes a stem and optionally a head component or a cup component. The stem is sized and shaped to fit into an intramedullary canal of the humerus. The proximal portion of the stem has a concave taper and the distal portion of the stem has a taper. The distal taper includes an anterior-posterior taper and a medial-lateral taper. The shape of the stem loads the metaphysis of the humerus with a greater load than the load applied to the diaphysis of the humerus.

Abstract: An implant for shoulder arthroplasty includes a stem and optionally a head component or a cup component. The stem is sized and shaped to fit into an intramedullary canal of the humerus. The proximal portion of the stem has a concave taper and the distal portion of the stem has a taper. The distal taper includes an anterior-posterior taper and a medial-lateral taper. The shape of the stem loads the metaphysis of the humerus with a greater load than the load applied to the diaphysis of the humerus.

Abstract: A stemless implant for shoulder arthroplasty includes a body having a proximal portion, distal portion, and an outer surface. A cylindrical extrusion is substantially perpendicular to and adjacent the proximal portion. At least a portion of the outer surface is configured to contact bone, the outer bone contacting surface comprising a concave taper. The stemless implant can be sized and shaped for insertion into a metaphysis of a humerus bone without penetrating a diaphysis of the humerus bone. The implant optionally comprises a medial fin, a lateral fin, an anterior fin, and a posterior fin. The medial fin and lateral fin may be thicker than the anterior fin. The fins may taper from the proximal portion to the distal portion.

Abstract: An implant for shoulder arthroplasty includes a stem and optionally a head component or a cup component. The stem is sized and shaped to fit into an intramedullary canal of the humerus. The proximal portion of the stem has a concave taper and the distal portion of the stem has a taper. The distal taper includes an anterior-posterior taper and a medial-lateral taper. The shape of the stem loads the metaphysis of the humerus with a greater load than the load applied to the diaphysis of the humerus.

Abstract: An implant for shoulder arthroplasty includes a stem and optionally a head component or a cup component. The stem is sized and shaped to fit into an intramedullary canal of the humerus. The proximal portion of the stem has a concave taper and the distal portion of the stem has a taper. The distal taper includes an anterior-posterior taper and a medial-lateral taper. The shape of the stem loads the metaphysis of the humerus with a greater load than the load applied to the diaphysis of the humerus.

Abstract: A multi-limb exercise machine and method that includes a plurality of user-movable input components, an input measurement device associated with each of the input components, a feedback device for providing the user with output information that indicates the difference between a current performance level and a performance target, and a processor that receives input information about user effort applied to each of the input components and communicates the output information to the feedback device. The input components are each configured to be moved by a limb of a user and to resist being moved. The processor determines the difference between performance levels based at least in part on a reward bias that decreases the difference more for effort applied to one of the input components than for effort applied to another of the input components.

Abstract: An implant for shoulder arthroplasty includes a stem and optionally a head component or a cup component. The stem is sized and shaped to fit into an intramedullary canal of the humerus. The proximal portion of the stem has a concave taper and the distal portion of the stem has a taper. The distal taper includes an anterior-posterior taper and a medial-lateral taper. The shape of the stem loads the metaphysis of the humerus with a greater load than the load applied to the diaphysis of the humerus.

Abstract: A multi-limb exercise machine and method that includes a plurality of user-movable input components, an input measurement device associated with each of the input components, a feedback device for providing the user with output information that indicates the difference between a current performance level and a performance target, and a processor that receives input information about user effort applied to each of the input components and communicates the output information to the feedback device. The input components are each configured to be moved by a limb of a user and to resist being moved. The processor determines the difference between performance levels based at least in part on a reward bias that decreases the difference more for effort applied to one of the input components than for effort applied to another of the input components.