Abstract: A femur bone cutting guide system (100) for use in a knee replacement surgical procedure includes a positioning guide in the form of a moulding (132), a bone cutting guide assembly 18 comprising bone cutting guide components (140, 142); and a guide mounting arrangement comprising a pair of mounting plates (144.1 and 144.2). The moulding (132) is constructed from anatomical data of the femur permitting it to be securely fitted to the lower extremity of the femur. Two attachment posts (154.1 and 154.2) which are connected to the moulding (132) provide for removable mounting of the components (140, 142) to the moulding. The components (140, 142) define guide formations for guiding a cutter for cutting prosthetic joint locating faces in the femur. The plates (144.1, 144.2) are removably mounted to the components (140, 142) and fixed to opposite sides of the femur. The components (140, 142) are then removed allowing removal of the moulding (132). Thereafter, the components are remounted to the plates (144.1, 144.

Abstract: A bone cutting guide system (110) includes a bone cutting guide assembly (111) and a positioning guide (114). The bone cutting guide assembly (111) includes a base pin (112) and a guide mounting arrangement comprising a placement pin guide (113). The pin (112) has an elongate cylindrical shaft (115) having a penetrating end (117). The positioning guide (114) includes a moulding (116) and a hollow cylindrical guide post (118) fixed to the moulding (116). The moulding (116) is constructed from anatomical data obtained by means of a radiographic scan of the head (55) of the femur (14) prior to surgery. The placement pin guide (113) has a handle (121) and a hollow cylindrical guide sleeve (119) dimensioned to slidingly receive the guide pin (112) therein. In use, the moulding (116) is fitted to the head (55) of the femur. The guiding formation (119) of the pin placement guide (113) is received in the post (118) for guiding the insertion of the pin (112) into the head (55) of the femur (14).