Imaging And Clinical Research About Posterolateral Plate Internal Fixation In Danis-Weber Type B Fracture Of Lateral Malleolus

Objective According with the characteristics of its natural bone cortex based on the imaging investigation and study of characteristics of the distal fibula bone cortex,and the comparison of curative effects of open reduction and internal fixation through lateral or posterolateral approach in Danis-Weber type B fractures of lateral malleolus.And to provide clinic basis in selection of methods of internal fixation for Danis-Weber type B fractures of lateral malleolus in the future.Methods 30 cases of normal adults' CT imaging data of ankle was obtain from radiology department.And the distal fibular(the talar dome to fibula far end)cortex characteristics was measured using Photo shop CS3 software.Each CT image of distal fibular would be divided into several parts:medial,lateral,front and back,when the image was measured.Then the area and rate of area of distal fibular cortex distal fibular cortex in each part was calculated by computer.The comparison of the relative thickness of bone cortex between medial and lateral or front and back were be implemented by the rate of area of distal fibular cortex distal fibular cortex which obtained previously.In addition,sagittal and coronal maximum length of distal fibular(the talar dome to fibula far end)was compared.At the same time,46 patients of lateral malleolus with Danis-Weber type B fractures were randomly divided into experimental group(group A)and control group(groupB).Patients in group A(n=23)were treated by open reduction and internal fixation with posterolateral plate,while patients in group B(n=23)were treated by open reduction and internal fixation with lateral plate.All patients were no use of plaster external fixation after surgery and asked to train ankle joint function with the same produce.After 2 weeks,the sutures would be removed and plaster external fixation would be used.When the the fracture line was fuzzy by X ray,the plaster external fixation would be removed and partly weight-bearing walking would be allowed until 3 months after surgery.After the healing of fracture,the internal fixation would be dismantled and AOFAS score would be used to evaluate the function of ankle after 1 month.In addition,the time for surgery,postoperative infection,fracture healing time,incision complications,range of motion of ankle also recordedResults When compared with bone cortex in the distal fibular(the talar dome to fibula far end),the area of back part was bigger than that of lateral part(P<0.01).When compared with sagittal and coronal maximum length(the talar dome to fibula far end),the sagittal maximum length was longer than that of coronal maximum length.While the AOFAS score,the time for surgery,postoperative infection and fracture healing time have no statistically significant differences between two groups(P>0.05);But from the results of follow-up,AOFAS score in group B whether in the total score or the score on pain,function,appearance were improved,however,there were no statistically significant differences between two groups.At the same time,the motion of ankle were superior than that of group A and had better heal incisions in patients of group B.Conclusion In the normal,the back part of distal fibular had bigger bone cortex and the sagittal maximum length was longer than that of coronal maximum length.The plate in back of distal fibular for Danis-Weber type B fractures of lateral malleolus should be more accord with the characteristics of its natural bone cortex and it could get better heal incisions,the motion of ankle,and relatively good prognosis.