Maturation of fracture callus leads to unloading of the fracture fixation hardware due to an increased load-share of the repair tissue. A novel data logger device (AO Fracture Monitor) continuously measures the decline in fixation hardware deflection under physiological loading as indirect indicator for the healing progress. Parameters obtained from the data logger device carry potential to significantly improve the assessment of fracture healing in the future. Meaningful interpretation of measurements requires a set of clinical reference data.~20 patients having received an AO large external fixator at the tibia will be equipped with a data logger device (AO Fracture Monitor) attached post-operation to a connection rod of the external fixator. The device continuously measures deformation of the fixator frame due to weight bearing for up to 4 months by means of a strain gauge. Several parameters are calculated from the recorded change in the strain signal and are stored at a regular interval. Data is collected from the AO Fracture Monitor at follow-up visits of the patient by wireless data transfer. Together with additional variables such as treatment details, fracture healing and pain reported by the patient, the collected data is used to build up a database. Data from the AO Fracture Monitor will be correlated with patient data to investigate the relevance and reliability of the data derived from the AO Fracture Monitor.~In this phase, the study does not imply changes on the operational treatment, nor does it allow for therapeutic consequences based on the derived data.
20 patients having received an AO large external fixator at the tibia will be equipped with a data logger device (AO Fracture Monitor) attached post-operation to a connection rod of the external fixator. The device continuously measures deformation of the fixator frame due to weight bearing for up to 6 months by means of a strain gauge. Several parameters are calculated from the recorded change in the strain signal and are stored at a regular interval.