A data-logging system to monitor bone fracture movement continuously

A compact system is presented, which can continuously monitor the occurrence of fracture site movement in patients with tibial shaft fractures treated with an Orthofix external fixator allowing limited axial movement. The system comprises a microswitch and data logger board, which are both attached to the fixator. Each time the switch is closed by the movement of the fixator, the data logger records it as an event. The number of events per half hour is stored to the board's memory. The data logger can record the frequency of movement for at least a four-week period, at which time, the data can be transferred to a computer via a serial link. The system has been proven in a limited patient trial. The results highlight the variation in patient mobility. The significance of continuously monitoring the fracture site movement during the healing period is discussed.