The Application Of Skeletal Three-dimensional Morphology Data Mining In Location Of Radial Head "Safe Zone" And Intraoperative Fluoroscopy Of Posterior Tibial Plateau

Background: With the wide use of the CT in clinic,the bone morphology measurement through three-dimensional manner is attract more attention recently.Direct “safe zone” location on CT axial view isn't work because the radial head is a circular shape.Previous “safe zone” location methods cannot work when doctor couldn't see the real radial head.The study is aiming to introduce a new method which can locate the "safe zone" through CT.Posterior tibial plateau fracture presents as a troublesome trauma.Anteroposterior and lateral view and sometimes plus a habitual 45° oblique view are often used to fully evaluate it in surgery.Through 45° view,posterolateral and posteromedial tibial plateau do show in the imaging,but whether it is the optimal display is without a further verification.We would compare the effect of different fluoroscopic angles and therefrom recommend a specific angle through which surgeons could quickly locate the posterolateral and posteromedial tibial plateau and get its promising and relative stable imaging.Materials and Methods: CT scan was applied to 20 intact upper extremity cadavers from 20 different corpses in full pronation and supination respectively.And intraoperative 3DCT of tibial plateau fracture was collected.These data is then imported to the software to gauge the parameters.Results: The “safe zone” scope is 114.41°±11.99.The rotation angle from the RL to “safe zone's” anterior border and posterior border line is 215.03°±5.99 and 100.62°±8.12.The rotation direction,clockwise or anti-clockwise,is based on the radius-ulna relative position.Posterolateral or posteromedial reading width changing not much from 0° to 34°,the down trending slope starts steepen at about 34°,and a snowslide slope is found near 42°.Overlapping width is presenting a gradually decreasing tendency.Conclusion: Radial head "safe zone" can be located in CT axial view based on the upper half of IB by this new method.The method is clinically applicable to distinguish whether the postoperative elbow mal-rotation is from plate impingement or not.34° is the best angle which has a relative acceptable width,less overlap and C-arm manipulation inaccuracy tolerance.0° view holds a wider reading width as well as the overlapping.