An implant system and apparatus configured to permit motion of the wrist
in at least one physiological direction, as well as in a dart thrower's
motion, and constrain motion of the wrist in at least one
non-physiological direction are provided. The implant according to one
embodiment includes a distal component and proximal component. Each of
the distal and proximal components includes a primary articulating
portion and a secondary articulating portion. Primary and secondary
articulating portions include at least one component having either a
substantially convex or a substantially concave shape. The secondary
articulating portion is configured to be radially and volarly disposed in
relation to the primary articulating portion.