OBJECTIVETo study the best entry points, direction and length of screw in acetabular anterior column plate technique, and to prevent the serious complications of screw penetrating the joint surface.

METHODSTwenty male cadaveric adult semi-pelvic specimen were taken, and the distance from anterior acetabular margin, posterior acetabular margin to anterior inferior iliac spine, iliopubic eminence and pubic tubercle were measured respectively. Determine and make serial cross-sections of the acetabular anterior column, measure the safe angle of screw entry on all entry points of each cross-section, and put all data into software SPSS 10.0 for statistics process.

RESULTSThe distance from anterior acetabular margin to anterior inferior iliac spine, iliopubic eminence and pubic tubercle was (25.4 +/- 1.4) mm, (11.8 +/- 0.7) mm and (37.4 +/- 1.5) mm respectively, the distance from posterior acetabular margin to anterior inferior iliac spine, iliopubic eminence was (15.5 +/- 0.9) mm and (29.1 +/- 1.6) mm respectively. On each cross-section, the maximum of the safe entry angle of inclination in 0.5 cm, 1.0 cm and 1.5 cm entry point lateral to the linea terminalis of pelvis was (8.2 +/- 2.2) degrees , (14.9 +/- 3.4) degrees and (26.1 +/- 4.5) degrees respectively.

CONCLUSIONSWhen plate for internal fixation on acetabular region of anterior column is used, there are three ways to avoid screw penetrating the joint surface. The first way is using short screw in any direction; the second way is using long screw close to the linea terminalis of pelvis, the direction of the screw is parallel to the quadrilateral plate; the third way is using different entry angle and length according to different entry point.