Patent attributes
Position reference members are provided as part of an orthopaedic implant system. Both position reference members can be implanted on or in the same bone as the other parts of the implant. One of the position reference members is fixed to the bone and the other position reference member is movable with another part of the implant, such as a stem received in the intramedullary canal. The movable position reference member can move with respect to the fixed position reference member. At least one of the position reference members includes indicia such as a main scale or a vernier scale. Parts of the indicia and position reference members are radio-opaque and parts are radiolucent. Post-operative changes in the relative positions of the position reference members can be measured by radiography or fluoroscopy so that changes in the implant position can be monitored over time.
