The present invention provides a uni-compartmental knee joint prosthesis (1) which includes a tibial component (2) and a femoral component (3). The tibial component (2) has a fixation portion (10) adapted to be fixed to an upper end of a prepared tibia (T) in a patient, and a bearing portion (30) presenting an articulation surface (32) formed from a ceramic material, wherein the bearing portion (30) is adapted for movement relative to the fixation portion (10). The femoral component (3) is adapted to be fixed to a lower end of a prepared femur (F) in a patient, and comprises a body portion (50) presenting an articulation surface (56) formed from a ceramic material for engagement with the articulation surface (32) of the tibial component (2). The articulation surfaces (32, 56) of the tibial and femoral components are adapted for essentially congruent engagement over a full range of movement of the prosthesis.
