Application Of Finite Element Analysis And Rapid Prototyping Technology In Treatment Of Quadrilateral Plate Fractures Of The Acetabulum

PART 1 Finite Element Analysis of Different Internal Fixation Methods for the Treatment of the Quadrilateral Plate Fractures of the AcetabulumPurposeThe aim of this study was to compare the biomechanical characteristics among different fixation methods in the quadrilateral plate fractures of the acetabulum by finite element analysis.MethodsA three-dimensional finite element model of the quadrilateral plate fractures of the acetabulum was simulated. Six kinds of implants were instrumented into the model, including acetabular anterior column reconstruction plate with periarticular long screws, infrapectineal plate, L-shaped plate, acetabular anterior-posterior column locking plate, acetabular anterior column reconstruction plate with blocking screw and cannulated screw. Loads of compression was distributed to the model. To evaluate the biomechanical properties, the construct stiffness, the micromotion of the quadrilateral plate, the stress distribution of implants were recorded and analyzed. Furthermore, the biomechanical properties under normal bone condition and mild and severe osteoporotic bone condition were recorded and analyzed.ResultsThe highest construct stiffness and the minimum displacement were provided by acetabular anterior column reconstruction plate with periarticular long screws and acetabular anterior-posterior column locking plate. The maximum Von Misses stress of implants appeared on the L-shaped plate. With the decrease of bone mass, the construct stiffness was reduced and the maximum displacement and the maximum Von Misses stress of implants were increased.ConclusionsFrom the finite element view, the acetabular anterior column reconstruction plate with periarticular long screws fixation method should be preferred in the treatment of the quadrilateral plate fractures of the acetabulum.PART 2 Application of the Rapid Prototyping Technology in the Treatment of the Complex Acetabular fractures involving Quadrilateral PlatePurposeTo introduce the application of the rapid prototyping technology in the treatment of the complex acetabular fractures involving quadrilateral plate and observe the effect of this technique on the operation.MethodsData of 41 consecutive patients with the complex acetabular fractures involving quadrilateral plate who were enrolled in our hospital from January 2009 to December 2013 were retrospectively observed. There were 18 patients who had undergone surgery with the rapid prototyping aided technology (rapid prototyping group), including 12 men and 6 women with an average age of 36.7 years. According to the Judet-Letournel classification,2,1,6,2 and 7 cases were T-type, posterior column and posterior wall, transverse and posterior wall, anterior column posterior hemitransverse and both-column, respectively. There were 23 patients who had undergone surgery without the rapid prototyping technology (conventional group), including 14 men and 9 women with an average age of 39.4 years. According to the Judet-Letournel classification,3,2,8,2 and 8 cases were T-type, posterior column and posterior wall, transverse and posterior wall, anterior column posterior hemitransverse and both-column, respectively. The Merle D’Aubigne & Postel score, Matta score, operation time, blood loss, blood transfusion, intraoperative fluoroscopy, iatrogenic injury and the complication were all recorded respectively.ResultsFor the rapid prototyping group, the operation time was 2.5-8.0 h, the blood loss was 600-1800 ml, the blood transfusion was 6-16 U and intraoperative fluoroscopy was 4-18 times. Excellent and good rate of Merle D’Aubigne & Postel score in the final follow-up was 72.2%. Excellent and good rate of Matta score in the final follow-up was 77.8%. For the conventional group, the operation time was 3.0-8.5 h, the blood loss was 800-2000 ml, the blood transfusion was 6-18 U and intraoperative fluoroscopy was 5-18 times. Excellent and good rate of Merle D’Aubigne & Postel score in the final follow-up was 73.9%. Excellent and good rate of Matta score in the final follow-up was 69.6%. There was statistical significance in the operation time, blood loss, blood transfusion and intraoperative fluoroscopy between two groups. There was no statistical significance in the Merle D’ Aubigne & Postel score and Matta score between two groups.ConclusionsSurgeons can make full preoperative planning by the rapid prototyping technology before the operation. This technology which reduces the operation time can make the operation more accurately, effectively and safely.