Abstract: A unicondylar posterior cutting block, method of use and kit of surgical components are provided, with the cutting block comprising: a base which is mountable on a resected proximal tibial surface of a knee of a patient in use; and a body pivotally attached to the base, the body including an alignment formation arranged to align with a marking on a femur in use, the body defining a cutting guide therein for receiving a cutting instrument to make a unicondylar posterior cut in the femur and wherein moving the alignment formation to align with the marking on the femur causes the body to rotate relative to the base and to tilt the cutting guide relative to the base. Different bases offer different cut positions and rotation of the base offers further different cut positions.

Abstract: The present invention provides monopolar acetabular liners (32, 54) that can enclose a femoral head (14) to form a hip replacement prosthesis (30, 50), wherein the liner (32, 54) has a rim (34) that creates an orifice, wherein the orifice has a diameter that is smaller than the diameter of the femoral head (14), and wherein the liner (32, 54) encompasses greater than 50 percent of the volume of the head (14), wherein a constraining ring (56) can be used in conjunction with the monopolar constrained acetabular liner (32, 54) to provide additional support for the femoral head (14) to stay with the acetabular liner (32, 54) and avoid dislocation. Assemblies and complete prosthetic replacements are also provided. Liners (32, 54) and constraining rings (56) having no, one or more recesses (36) also are provided.