Acetabular fractures are the resultant from high-energy trauma or low-energy trauma in the elder patients. Usually, surgeons use LETOURNEL's classification or/and JUDET's one.

Five elements are considered and associated to five type of fracture. Even more, for orthopaedic surgeons with less experience with these fractures, correct classification can be more difficult.

So the the aim of this study is:

1. Evaluate the efficacy of four "special" 3D reconstruction: a 3D reconstruction of the pelvis with anterior view, posterior view, endopelvic view where the opposite hemipelvis removed and an exopelvic view where the femoral head is removed according to the initial teaching of E. Letournel.
2. Evaluate the addition of teaching of non-experimented surgeon on the accuracy of classifying acetabular fractures.
3. Evaluate the addition of a digital algorithm (mobile application) on the accuracy of classifying acetabular fractures.

12 reviewers will be given the different imaging of each case and will be divided in 4 groups: novice (junior ER and ortho residents), intermediate (non-experimented orthopedic surgeons), intermediate with a formation on classifying acetabular fractures and finally experts (acetabular fracture expert surgeons) . For each patient, representative CT scans are provided for each assessment. The study will be divided into 3 phases separated by 4-6 weeks of time. In the first phase, for each patient, representative CT scans are provided for each assessment with 2D and multiplanar reconstruction (MPR) without 3D views. In the second phase, 3D views are added. In the third phase, the cases are evaluated using the "Acetabular Diagnosis Tool" To note, the evaluation of the cases is done twice in each phase separated by 4-6 weeks and the order of the cases is changed, both in order to minimize recall bias

Inclusion Criteria:

• acetabular fracture

Exclusion Criteria:

• no criteria

patients with acetabular fracture surgery