1. A system for identifying a landmark, the system comprising: a field generator for generating a magnetic field; an orthopedic implant having at least one landmark, the orthopedic implant defining a cannulation and a longitudinal groove, the longitudinal groove having a proximal end region and a distal end region, wherein the orthopedic implant defines a first opening in an exterior surface of the orthopedic implant, the first opening being open to the longitudinal groove, and wherein, at a location adjacent the opening, the orthopedic implant defines a second opening to receive a cover for the first opening; a cover that is insertable into the second opening such that the cover covers the first opening and is substantially flush with an external surface of the implant when disposed in the second opening; a first magnetic sensor mounted to the orthopedic implant, the first magnetic sensor comprising one or more sensor coils disposed in a sensor housing, the first magnetic sensor being located in the distal end region of the longitudinal groove and being spaced apart from the at least one landmark a set distance, the first magnetic sensor being configured to produce sensor data responsive to the magnetic field; a landmark identifier; and a processor configured to analyze sensor data from the first magnetic sensor and data from the landmark identifier and use the set distance to calculate a position of the landmark identifier relative to the at least one landmark.