During total hip replacement (THR) surgery, the sensor data is obtained in vivo and transmitted wirelessly to a computer where the data is processed and displayed on a screen. In addition, some low-power technologies are adopted in both the hardware and software implementation to ensure the battery lifetime of the system can fully cover the whole THR surgery. More details about the system are provided with an introduction to the system architecture and a discussion of the vision- and IMU-based prosthetic pose estimation methods. The low-power technologies adopted in the system are described and the implementation and experimental results are presented.