Fracture reduction and screw position after 3D-navigated and conventional fluoroscopy-assisted percutaneous management of acetabular fractures: a retrospective comparative study.

BACKGROUND: Navigational techniques in orthopaedic trauma surgery have developed over the last years leaving the question of really improving quality of treatment. Especially in marginal surgical indications, their benefit has to be evident. The aim of this study was to compare reduction and screw position following 3D-navigated and conventional percutaneous screw fixation of acetabular fractures. The study hypothesis postulated that better fracture reduction and better screw position are obtained with 3D navigation. MATERIALS AND METHODS: Preoperative and postoperative CT scans of 37 acetabular fractures treated by percutaneous screw fixation (24 3D-navigated, 13 conventional) were evaluated. Differences in pre- and postoperative fracture gaps and steps were compared in all reconstructions as well as the screw position relative to the joint and the fracture. RESULTS: The differences in fracture gaps and fracture steps with and without 3D navigation were not significantly different. Distance of the screw from the joint line, angle difference between screw and ideal angle relative to the fracture line, length of the possible corridor used and position of the screw thread did not show any significant differences. CONCLUSION: Comparison of 3D-navigated and conventional percutaneous surgery of acetabular fractures on the basis of pre- and postoperative CTs revealed no significant differences in terms of fracture reduction and screw position.

[3D safety in osteosynthesis adjacent to joints]. / 3-D-Sicherheit bei gelenknahen Osteosynthesen.

BACKGROUND: The results and immediate consequences of intraoperative three-dimensional (3D) imaging in the treatment of AO classification type C fractures of the distal radius, the tibial head and the tibial pilon were analyzed and compared with published results on general intraoperative revision rates following intraoperative 3D-imaging. METHODS: In this retrospective study 279 patients with AO type C fractures of the distal radius (n = 84), tibial head (n = 109) and tibial pilon (n = 86) who underwent intraoperative 3D-imaging were included. The findings of the 3D-imaging and the intraoperative revision rates were analyzed and compared with previously published results of our working group. RESULTS: In 70 out of 279 patients (25 %) an intraoperative revision was carried out following 3D-imaging. The revision rates were 15 % for fractures of the distal radius, 27 % for fractures of the tibial head and 32 % for fractures of the tibial pilon. The most common reason for immediate intraoperative revision was the necessity for improved repositioning due to a remaining step in the articular surface in 51 out of 279 patients (18%). CONCLUSION: Intraoperative revision rates following 3D-imaging increased with the severity of the injury pattern. Intraoperative 3D-imaging should be routinely used in the treatment of fractures of the tibial head, tibial pilon and even in comminuted distal radius fractures due to the high intraoperative revision rates found in the present study. Alternatively, a postoperative computed tomography (CT) control should be performed.

Diagnostic accuracy of intraoperative CT-imaging in complex articular fractures - a cadaveric study.

Anatomic reconstruction of articular fractures is one of the critical factors in later achieving good functional outcome. Intraoperative 3D imaging has been shown to offer better evaluation and therefore can significantly improve the results. The purpose of this study was to assess the difference between intraoperative three-dimensional fluoroscopy (3D) and intraoperative computed tomography (iCT) imaging regarding fracture reduction, implant placement and articular impressions in a distal humeral fracture model. AO type 13-B2 fracture pattern were created in upper extremity cadaver specimens. Articular step-offs, intra-articular screw placement and intraarticular impressions of different degrees of severity were created. All specimens had imaging performed. For each articular pattern 3D fluoroscopy in standard (3Ds) and high quality (3Dh) were performed (Arcadis Orbic, Siemens, Germany) as well as an intraoperative CT scan (iCT, Airo, Brainlab, Germany). Three observers evaluated all imaging studies regarding subjective and objective parameters. iCT is more precise than 3D fluoroscopic imaging for detection of articular impressions. Articular step-offs and intraarticular screw placement are similar for iCT and 3D. Subjective imaging quality is the highest for iCT and lowest for 3Ds. Intraoperative CT may be particularly useful in assessing articular impressions and providing a good subjective image quality for the surgeon.

2D projection-based software application for mobile C-arms optimises wire placement in the proximal femur - An experimental study.

PURPOSE: A new software application can be used without fixed reference markers or a registration process in wire placement. The aim was to compare placement of Kirschner wires (K-wires) into the proximal femur with the software application versus the conventional method without guiding. As study hypothesis, we assumed less placement attempts, shorter procedure time and shorter fluoroscopy time using the software. The same precision inside a proximal femur bone model using the software application was premised. METHODS: The software detects a K-wire within the 2D fluoroscopic image. By evaluating its direction and tip location, it superimposes a trajectory on the image, visualizing the intended direction of the K-wire. The K-wire was positioned in 20 artificial bones with the use of software by one surgeon; 20 bones served as conventional controls. A brass thumb tack was placed into the femoral head and its tip targeted with the wire. Number of placement attempts, duration of the procedure, duration of fluoroscopy time and distance to the target in a postoperative 3D scan were recorded. RESULTS: Compared with the conventional method, use of the application showed fewer attempts for optimal wire placement (p=0.026), shorter duration of surgery (p=0.004), shorter fluoroscopy time (p=0.024) and higher precision (p=0.018). Final wire position was achieved in the first attempt in 17 out of 20 cases with the software and in 9 out of 20 cases with the conventional method. CONCLUSIONS: The study hypothesis was confirmed. The new application optimised the process of K-wire placement in the proximal femur in an artificial bone model while also improving precision. Benefits lie especially in the reduction of placement attempts and reduction of fluoroscopy time under the aspect of radiation protection. The software runs on a conventional image intensifier and can therefore be easily integrated into the daily surgical routine.