Ankle prosthesis with anatomic range of motion

An ankle prosthesis implant comprising:

• a talar implant defining a superior bearing surface, the superior bearing surface including:
• a convex portion defined in an anterior-posterior direction when viewed from a sagittal plane and having a neutral axis (X1) defined in a coronal plane at an anterior-posterior midline of the talar implant and extending in a medial-lateral direction, and
• a concave portion defined in the medial-lateral direction when viewed from the coronal plane, the concave portion being swept about a secondary axis (X2) that is angled upwards relative to the neutral axis (X1) in the medial-lateral direction towards a medial end of the talar implant by an angle (θ), and the angle (θ) of the secondary axis (X2) relative to the neutral axis (X1) is tilted upwards by at least 1° toward the medial end of the talar implant;
• and
• a bearing component that articulates with the talar implant, said bearing component defining an interfacing surface having a width (W1) in the medial-lateral direction that is less than a width (W2) in the medial-lateral direction of an interfacing surface of the talar implant, and the width (W2) of the talar implant allows the bearing component to articulate by at least 1° in inversion or eversion.