A method includes inserting a guide mount into a space between a talus and a tibia until a mating portion having a conformal bone engaging surface is disposed against the tibia. An instrument guide is into a cavity defined by the guide mount such that an opening defined by a superior wall of the instrument guide aligns with an opening defined by a superior wall of the guide mount. A reamer head disposed within the opening defined by the instrument guide is connected to a flexible reamer shaft that is received within a passageway defined by the instrument guide. The talus is reamed with the reamer head driven by the flexible reamer shaft.
