Three-dimensional Finite Element Analysis Of Different Bone Tunnel In The Process Of The Talar Ischemic Necrosis Treatment By Periosteal Flap With Vascular Pedicle

Objective: Using Three-dimensional finite element to simulate normal astragalus,ischemic necrosis of talus and simulation of ischemic necrosis of talus underwent surgical treatment. Analysis of stress and displacement on the surface of the talus data changes,Find out the most suitable bone tunnel scheme, guide the clinical treatment of osteonecrosis.Methods: The data of ankle was been obtained by though scaning the normal ankle wihe 64 row spiral CT,and to build ankle model with the help of image processing software Minics and finite element software Ansys 10.0,using finite element software to simulate ischemic necrosis of talus and further treatment of ischemic necrosis of talus, Including In a different direction of the talus neck bone tunnel for the reduced pressure, dig out the dead bone, implanted periosteal flap with vessel pedicle. Analyzing the nature standing people data changes on the surface of the talus,to find the best bone tunnel for talus osteonecrosis.Results: The three-dimensional finite element model of talus was been successfully established, There are altogether 159271 nodes, 122442 units, the 110898 cancellous bone, 11544 compact bone in the model.The talus model that was builded closed to reality. When the lateral necrosis of talus had been happened,In the stress,by comparing we find the stress of the necrosis talus was greater than the normal talus obviously;After drilling the bone tunel,the stress decreases in turn from outsite bone tunel to inner bone tunel,and the stress of the talus was all less than the stress of the necrosis talus,but all greater than normal talus,In the displacement, the necrosis talus was less than the normal talus,the displacement decreases in turn from outside bone tunel to inner bone tunel,but all greater than normal and necrosis talus.The result of the innerside necrosis of talus was the same with the the lateral necrosis of talus.In the stress.Stress of the necrosis talus was greater than the normal talus,inner side bone tunel was maximum,the middle bone tunel was the minimum by comparing.In the displacement,the middle and inner side bone tunel was the same,but all less than outside bone tunel.Conclusion:Through this experiment, The three-dimensional finite element model of normal and ischemic necrosis of talus was established successfully. By analyzing the normal talus, ischemic of talus and after drilling bone tunel of talus,the experimental results showed that the stress of the ischemic nerosis was greater than the normal,Through drilling the bone tunel, the stress on the surface was smaller than the ischemic of the talus,Through comparison on different schemes are we found that when the lateral necrosis of talus, the inside of the talus bone tunnel scheme is the best, When the inside of the talus ischemic necrosis occurs, the change has no obvious difference between the three kinds of treatment, but in comparison, bone tunnel project in the middle is the best.