A substantially cup-shaped prosthetic device for a joint, comprising: an outer surface substantially shaped in the form of a sphere and configured to operatively engage at least one of a first bone (12, 22) of the joint and a component; and an inner surface (60, 160, 260, 360) configured to connect to a second bone (14, 16) of the joint, wherein the inner surface (60, 160, 260, 360) includes a bone-engaging first concave surface (62, 162, 262, 362) and a bone-engaging second concave surface (64, 164, 264, 364) and a wall thickness (t) of the prosthetic device is non-constant such that a shape of the first concave surface (62, 162, 262, 362) is different from the shape of the second concave surface (64, 164, 264, 364), wherein the first concave surface (62, 162, 262, 362) and the second concave surface (64, 164, 264, 364) face inward toward a center axis (H-H) passing through the geometric center of the sphere of the prosthetic device, CHARACTERISED IN THAT: the first concave surface (62, 162, 262, 362) is rotationally asymmetric about the center axis (H-H) passing through the geometric center of the sphere of the prosthetic device such that an arc along the first concave surface in a plane perpendicular to the center axis (H-H) has a non-constant radius of curvature such that a wall thickness between the outer surface and the first concave surface (62, 162, 262, 362), taken along the plane perpendicular to the center axis (H-H), is less than a wall thickness between the outer surface and the second concave surface (64, 164, 264, 364) taken along the plane perpendicular to the center axis (H-H); and the outer surface and the inner surface terminate at an edge formed at a plane (T-T) perpendicular to the center axis (H-H), but for at least one cutout formed by a portion of the edge that is raised from the plane (T-T). an outer surface substantially shaped in the form of a sphere and configured to operatively engage at least one of a first bone (12, 22) of the joint and a component; and an inner surface (60, 160, 260, 360) configured to connect to a second bone (14, 16) of the joint, wherein the inner surface (60, 160, 260, 360) includes a bone-engaging first concave surface (62, 162, 262, 362) and a bone-engaging second concave surface (64, 164, 264, 364) and a wall thickness (t) of the prosthetic device is non-constant such that a shape of the first concave surface (62, 162, 262, 362) is different from the shape of the second concave surface (64, 164, 264, 364), wherein the first concave surface (62, 162, 262, 362) and the second concave surface (64, 164, 264, 364) face inward toward a center axis (H-H) passing through the geometric center of the sphere of the prosthetic device, CHARACTERISED IN THAT: the first concave surface (62, 162, 262, 362) is rotationally asymmetric about the center axis (H-H) passing through the geometric center of the sphere of the prosthetic device such that an arc along the first concave surface in a plane perpendicular to the center axis (H-H) has a non-constant radius of curvature such that a wall thickness between the outer surface and the first concave surface (62, 162, 262, 362), taken along the plane perpendicular to the center axis (H-H), is less than a wall thickness between the outer surface and the second concave surface (64, 164, 264, 364) taken along the plane perpendicular to the center axis (H-H); and the outer surface and the inner surface terminate at an edge formed at a plane (T-T) perpendicular to the center axis (H-H), but for at least one cutout formed by a portion of the edge that is raised from the plane (T-T). the first concave surface (62, 162, 262, 362) is rotationally asymmetric about the center axis (H-H) passing through the geometric center of the sphere of the prosthetic device such that an arc along the first concave surface in a plane perpendicular to the center axis (H-H) has a non-constant radius of curvature such that a wall thickness between the outer surface and the first concave surface (62, 162, 262, 362), taken along the plane perpendicular to the center axis (H-H), is less than a wall thickness between the outer surface and the second concave surface (64, 164, 264, 364) taken along the plane perpendicular to the center axis (H-H); and the outer surface and the inner surface terminate at an edge formed at a plane (T-T) perpendicular to the center axis (H-H), but for at least one cutout formed by a portion of the edge that is raised from the plane (T-T).