Study Of A Modular Plastic Splint Based On Micro-movement And Axial Traction

Distal radius fracture happens within 3cm away from the distal radius articular.The incidence rate of it is almost 17% of emergency patients with fractures.For stable fractures,patients often choose external fixation(plasters or splint)recovery.Radial shortening is the most important factor in the recovery of distal radius fracture,and axial traction can effectively reduce the tendency to radial shortening.However,the present magnitude of traction force relies on feedback between doctors and patients,which is very subjective and not exact.Flexible fixation refers to keeping the fracture fragments still and allowing the ends of the fracture to move slightly.This method comes from Chinese medicine splint and has unique advantage in solving stress shielding problem and promoting the rapidity and stability of fracture healing.However,the present splint is not fixed enough in the early stage of healing,prone to cause fracture displacement,and is subjectively adjusted.This study has three main elements:1)To fill the research empty,this study chooses the corpses upper limb specimens as experimental subject and obtains the relationship of axial traction force and the displacement of fracture ends by mechanical experiments,providing guidance of traction force controlling to help doctors carry out closed manipulative reduction.It is also an important reference for design of external fixation(such as plastic medicine splint).2)This study brings forward an idea of modular elastic splint,which adds flexible model into present elastic splint,and could achieve "absolute fixed" in early healing stage with axial traction force and "micro movement" in post-healing stage.The physical model of this idea is made with 3d printing technology and the force-model and geometric model is discussed in this study.3)To obtain the relationship of push force and pendulum angle,elastic coefficient of wrist joint is an important effect variable.An experiment about axial displacement of modular elastic splint with the traction force is carried out to obtain the relationship.The experiment result can provide important data reference for the next development of the design of modular elastic splint.