A Trial of Measuring the Displacement of Tibial Fragments with Pinless External Fixator

Currently, the mechanical performances of pinless external fixator are primarily evaluated for application to long bone fractures. A new method that detecting the relative displacement changes of the tibial fragments with the pinless external fixator by the three dimensional measurement system was introduced to evaluate the performance of the pinless external fixator. And such testing item was taken as the complement for the mechanical performances of the pinless external fixator. In this paper, a high precision optical 3D measurement system was used to detect the displacement change in the anterior and posterior fracture part of the tibial bones which was fixed by a clamp pattern pinless external fixator in open tibial fractures. Furthermore, the relative displacement change and relative angle rotation were analyzed after obtaining the trajectory of the markers which fixed on the tibial fragments, the results were used to evaluate the stability of the pinless external fixator, and taken as the reference for revising the design of the pinless external fixator as well