Ellipsoid and toroid-shaped articulations for total wrist prostheses were evaluated using computer modeling and laboratory experiments. An ellipsoidal design was found to accommodate greater width of the concave proximal component, resulting in better capture and prosthetic stability than a toroid shape. An ellipsoid articulation also provides greater contact area through the available arc of motion. An ellipsoidal articulation is a reasonable design for total wrist arthroplasty.