Objective To explore the clinical effectiveness and reliability of combined acetabular quadrilateral surface plates for the treatment of both column fractures.Methods From June 2016 to August 2017,data of 15 cases with acetabular both column fractures who were treated in our department were retrospectively analyzed.Among them 9 cases were male and 6 were female.The mean age was 42.8 years (range,26-68 years).All cases were both column fractures according to the LetournelJudet's classification,including 4 cases combined with posterior wall fracture.Before operation,the pelvic CT thin layer scanning data of patients were collected in DICOM format,and then the data were imported to print the simulated model by 3D printing technology in order to understand the characteristics of fracture directly.The contralateral half pelvis was mirror printed in order to simulate the placement of combined quadrilateral surface plates and preshape all plates.During operation,infrapectineal main plate,pubo-ischiatic plate and ilio-ischiatic plate were placed consequently to fix the anterior column,"middle column" and posterior column respectively.The pubo-ischiatic and ilio-ischiatic plates were combined with the main plate.All cases were operated by supra-ilioinguinal approach.Results The average incision length was 11 cm (range,9-13 cm).The average operative time was 150 min (range,100-240 min).The average blood loss was 850 ml (range,600-1500 ml).Once reduction was obtained,plates could be placed easily and adhere to bone surface well.The quality of postoperative fracture reduction was evaluated according to Matta standard,of which there were 9 cases excellent,4 cases good,and 2 cases poor,with an excellent rate of 86.7％ (13/15).All patients were followed up for an average time of 10 months (range,6-12 months).At the latest follow-up,the average modified Merle d'Aubigne and Postel score was 16.4 (range,12-18),and there were 8 cases excellent,4 cases good,2 cases fair and 1 case poor,with an excellent rate of 80.0％ (12/15).Conclusion For the treatment of acetabular both column fractures,the combined quadrilateral surface plates could resist the medial displacement of quadrilateral area,and on the other hand the total floating posterior column and ischium could be fixed firmly.At the same time,this plate system is a multi-dimensional framework fixation,which is more effective and safer with lower complications rate,resulting in a satisfactory clinical outcomes.