Apparatus comprising: a tool positioning jig (22) for postioning a tool holder (24)； a cyclical saw removably mountable to the tool holder for making a distal tibial cut； a talus positioning guide (32) removably mountable to the tool holder for postioning location holes； a talus resection guide (34) alignable with the location holes and providing a cutting face (34e) for making a superior talar cut； an ankle alignment jig (36) for setting the position of one or more slots in the tibia and for setting the position of one or more guide holes to be drilled in the talus； a talus drill template (38) comprising one or more pins (38a) and one or more drill guides (38b) for setting the position of at least one further hole in the talus； a talus roof top preparation guide (40) comprising at least two pins (40b), configured to be received respectively by the one or more guide holes and at least one further hole in the talus, the roof top preparation guide further comprising two large diameter holes (40b) for receiving a cutting tool； a talus routing guide (44) for positioning one or more slots in the talus, and a manipulator (46) for positioning the artificial ankle joint between the tibia and talus, the manipulator comprising a handle portion (46b) and a body portion, wherein the body portion comprises at least one mounting point (46c) configured to engage with the artificial ankle joint and a direction guide configured to prevent the artificial ankle joint from being incorrectly inserted into the tool.L'appareil concerne un appareil comprenant : un montage (22) de positionnement d'outil pour positionner un porte-outil (24) ； une scie cyclique montée d'une manière amovible sur le porte-outil, pour réaliser une coupe tibiale distale ； un guide (32) de positionnement du talus, pouvant être monté d'une manière amovible sur le porte-outil pour positionner des trous de positionnement ； un guide (34) de résection du talus, pouvant être aligné avec les trous de positionnement et fo
