Ankle prosthesis

A prosthesis for total ankle arthroplasty, comprising:

• a talar implant;
• a tibial implant;
• and
• a bearing component disposed between the tibial implant and talar implant and configured to slide relative to the talar implant to facilitate motion of the prosthesis,
• wherein:
• the bearing component and the talar implant have corresponding sliding surfaces, the corresponding sliding surfaces defining concentric cylindrical surfaces and an axis of rotation, the axis of rotation defining a first direction;
• the concentric cylindrical surface of the bearing component has a ridge configured to slide in a corresponding groove in the concentric cylindrical surface of the talar implant;
• the alignment of the bearing component and the talar implant, along the axis of rotation, is only due to the interaction of the ridge and the groove;
• and
• the bearing component and the tibial implant have corresponding flat sliding surfaces;
• and the bearing component is configured to slide relative to the tibial implant in multiple directions including the first direction.