Fig. 3

Typical case: A 23-year-old woman presented with T-shaped fracture of the right acetabulum (Letournel-Judet classification). Preoperative X-ray (a) and CT 3d reconstruction (b–c) showed significant fracture displacement of quadrilateral plate. Dynamic anterior plate-screw system for quadrilateral plates (DAPSQ) fixation was performed by using the ilioinguinal approach. Postoperative X-ray (d) showed good fracture reduction. Postoperative 3D CT reconstruction showed residual displacement was less than 1 mm and graded as excellent according to classic Matta criteria. e The anterior inclined angle of quadrilateral plate was 86.90°; f The middle inclined angle of quadrilateral plate was 92.19°; g The posterior inclined angle of quadrilateral plate was 104.69°. All the three inclined angles were not within normal range, and rated as poor according to evaluation criteria of inclined angles. Combined with the classic Matta criteria, the modified Matta criteria of this patient graded as good. The Harris hip score of the last follow-up was 75, graded as fair