No abstract

Acetabular fractures can be challenging to treat, in part because the shape of the fixation plates needs to be adjusted during the surgical procedure. One possibility is to generate a model of the uninjured half of a fractured pelvis with 3D printing, and then pre-contour the fixation plates preoperatively on this model. The purpose of this technical note is to describe how we used 3D printing as an aid to treat acetabular fractures. The quality of the fracture reduction, fracture fixation and time savings were evaluated. Three-dimensional reconstructions of the preoperative CT scan of the pelvis were exported with OsiriX™ software, mirrored with Meshmixer™ software and then printed in polylactic acid (PLA). Two fracture fixation plates were pre-contoured on the printed hemipelvis and then sterilized. No additional intraoperative contouring was needed. Anatomical reduction was obtained with an estimated 30-minute time saving and € 6 consumables cost.

Level III, non-randomised prospective case-control diagnostic study.

Objectives: To evaluate the accuracy of reduction of the acetabular articular surface using an intraoperative computed tomography scanner (O-Arm) and screw navigation compared with a classical open technique. Design: Prospective matched cohort study. Setting: Tertiary referral center. Patients/Participants: Adult patients with acute acetabular fractures were included in the study. All patients were treated by 2 senior surgeons using intraoperative imaging and screw navigation. Main Outcome Measurements: The primary outcome measure was articular reduction. Secondary outcomes were radiation dosage, operative variables [operative time, time for image acquisition, intraoperative bleeding (cell saver), number of surgical plates, and number of screws], and postoperative variables (first postoperative day pain on the visual analog scale, postoperative transfusion, and hemoglobin change). P < 0.05 was considered statistically significant. Results: Thirty-five patients were treated in the inclusion period (2016–2017) and were matched to 35 cases in our database (2013–2016). Mean age was 43 years, and the most common fracture type was a both-column fracture (OTA/AO type C). Postoperative image analysis showed that reduction was achieved in 87.1% of the cases in the O-Arm group versus 64.7% in the control group (P < 0.05). Mean gap of the articular fragments was 3.6 mm in the O-Arm group compared with 5.6 mm (P = 0.01) in the control group. There was no significant difference between the 2 groups in regards to all other studied variables except a decrease in intraoperative blood loss and transfusions and an increase in surgical time with the O-Arm group. Finally, the total radiation dose was decreased using the intraoperative O-Arm compared with a routine postoperative computed tomography scan (dose length product in O-Arm: 498 mGy.cm; dose length product in historical group: 715 mGy.cm). Conclusions: Using intraoperative imaging and screw navigation for displaced acetabular fractures allow screw navigation with increasing articular surface reduction accuracy. Operative and anesthesia times were not increased, whereas radiation exposure to the patient was significantly decreased. We recommend the use of intraoperative imaging for the treatment of displaced acetabular fractures. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Background:Accurate classification of acetabular fractures remains difficult. To aid in the classification of acetabular fractures and to aid in teaching, our department developed a diagnostic algorithm that involves the use of 1 standardized 3-dimensional reconstruction of a computed tomography (CT) scan (an exopelvic view without the femoral head) with 8 anatomical landmarks. The algorithm was integrated into a smartphone application (app). The main objective of this study was to test the efficacy of this algorithm and smartphone app.Methods:Fourteen reviewers (3 experts, 3 fellows, 3 residents, and 5 novice reviewers) evaluated a set of 35 CT scans of acetabular fractures in 2 phases. During the first phase, the scans (including axial 2-dimensional views and 3-dimensional (3D) multiplanar reconstruction views) were assessed by each reviewer twice, with an interval of 4 weeks between the readings to decrease recall bias. During that phase, the reviewers were provided with a diagram of the Letournel classification system with no guidelines for interpretation. During the second phase, performed 4 weeks after the first phase, 1 standardized 3D reconstruction (an exopelvic view without the femoral head) was reviewed twice, with an interval of 4 weeks between the readings. During that phase, the reviewers used the smartphone app. The primary outcome was the accuracy of classification. Interobserver reliability, reading time, and time needed for accurate classification were noted.Results:The accuracy of fracture classification was 64.5% when the standard method of analysis was used and 83.4% when the app was used (p < 0.001). Improvement was noted in all groups, with the expert group showing the least improvement (88.6% to 97.2%, p = 0.04) and the novice group showing the most improvement (42.0% to 75.5%, p < 0.001). Furthermore, use of the app greatly increased the accuracy of classification of complex fractures. The average reading time was 71.8 minutes when the standard method was used and 37.4 minutes when the app was used. The interobserver reliability improved in all groups to an excellent reliability (interclass correlation coefficient [ICC] > 0.79).Conclusions:The Letournel classification system is difficult to understand and to learn but remains the only system guiding the surgical strategy for acetabular fractures. The impact of diagnostic algorithms is debatable. The most important finding of the present study is the high accuracy for inexperienced groups when the app was used. Another important finding is the high reliability of this method for the diagnosis of complex acetabular fractures.

Acetabular fracture diagnosis according to Letournel classification is difficult and depends greatly on the experience of the reader. The described set of 3D images yields better accuracy and renders the diagnosis more repeatable and faster. We recommend the use of these images in classifying acetabular fractures.

Posterior wall with transverse acetabular fractures represents the most common type of acetabular fractures and is generally associated with poorer outcomes. This is caused by improper visualization of the fragments leading to imperfect reductions. Navigation in pelvic and acetabular trauma is reserved nowadays to non-displaced or mildly displaced fractures. To add to that, perioperative control of reduction is difficult using the conventional X-ray. The described 3D imaging method allowed proper reduction control. On the other hand, screw navigation of acetabular screws enabled better control of screw position as well as screw placement in otherwise inaccessible zones. In conclusion, peroperative 3D imaging and screw navigation optimize fracture reduction promoting better radiological and functional results.

Level V: expert opinion.