An orthopaedic prosthesis comprising a tibial tray (12) having a platform (14) extending downwardly from a bottom surface (18) of the platform, a spacer (38) which can be coupled to an end of the stem of the tibial tray, the spacer being formed from an electrically insulating material, a stem extension (36) which can be coupled to the spacer, and a wireless communication device (70) electrically coupled to the stem extension via an antenna wire (66) and configured to transmit data using the stem extension as an antenna.
