(1) Background: The incidence of fragility fractures of the pelvis (FFP) has increased significantly over the past decades. Unilateral non-displaced fractures, defined as FFP II, are the most common type of fracture. When conservative treatment fails, surgical treatment is indicated. We hypothesize that the use of bilateral SI screws (BSIs) or a transsacral screw (TSI) is superior compared to a unilateral screw (USI) because of a significant reduction in the risk of adjacent fractures and a reduction in fracture progression. (2) Methods: A finite element model of a female pelvic ring was constructed. The ligaments were simulated as tension springs. The load was applied through the sacrum with the pelvis fixed to both acetabula. An FFP IIc was simulated and fixed with either a USI or BSI or TSI. The models were analyzed for a quantitative statement of stress and fracture dislocation. (3) Results: The BSI and TSI resulted in less dislocation compared to the USI. The stress distribution on both sides of the sacrum was favorable in the BSI and TSI groups. The BSI resulted in a higher rotational stability compared to the TSI. (4) Conclusions: The use of either a BSI or TSI for fixation of unilateral FFP is biomechanically favorable compared to the use of a USI. In addition, the use of a BSI or TSI reduces the stress on the contralateral uninjured side of the sacrum. This may reduce the risk of an adjacent fracture or fracture progression.

Background: The treatment of ankle fractures involving the posterior malleolus (PM) has changed in favor of open reduction and internal fixation (ORIF), and the need for additional syndesmotic stabilization has decreased; however, there are still doubts regarding the diagnosis and treatment of residual syndesmotic instability. The aim of the present study was to evaluate the effect of fixation of the PM and to assess the need for additional stabilization methods. We hypothesized that ORIF of the PM would not sufficiently stabilize the syndesmosis and that additional syndesmotic reconstruction would restore kinematics. Methods: Eight unpaired, fresh-frozen, cadaveric lower legs were tested in a 6-degrees-of-freedom robotic arm with constant loading (200 N) in the neutral position and at 10° dorsiflexion, 15° plantar flexion, and 30° plantar flexion. The specimens were evaluated in the following order: intact state; osteotomy of the PM; transection of the anterior inferior tibiofibular ligament (AITFL) and interosseous ligament (IOL); ORIF of the PM; additional syndesmotic screw; combination of syndesmotic screw and AITFL augmentation; and AITFL augmentation. Results: A complete simulated rupture of the syndesmosis (PM osteotomy with AITFL and IOL transection) caused translational (6.9 mm posterior and 1.8 mm medial displacement) and rotational instability (5.5° external rotation) of the distal fibula. ORIF of the PM could eliminate this instability in the neutral ankle position, whereas sagittal and rotational instability remained in dorsiflexion and plantar flexion. The remaining instability could be eliminated with an additional procedure, without notable differences between screw and AITFL augmentation. Conclusions: In our model, isolated PM osteotomy and isolated AITFL and IOL rupture (after PM refixation) only partially increased fibular motion in dorsiflexion and plantar flexion, whereas the combination of PM osteotomy and AITFL and IOL rupture resulted in an unstable syndesmosis in all planes. Clinical Relevance: In complex ankle fractures, ORIF of the PM is essential to restore syndesmotic stability; however, residual syndesmotic instability can be detected by a specific posterior shift of the fibula on stress testing. In these cases, anatomical AITFL augmentation is biomechanically equivalent to the use of a syndesmotic screw.

Aims: Cardiac implantable electronic device (CIED) patients are routinely advised against physical activity with a risk of collision because of expected damage to the implanted device. However, no data support this practice. Methods and results: Sixteen CIED systems (six pacemakers, six ICD, four CRT-D) from all manufacturers were implanted subcutaneously in a porcine thorax and increasing weights were dropped on the experimental setting. Cardiac implantable electronic device function was analysed in an interactive heart simulator (InterSim III, IB Lang). In a second experiment, forces resulting in irreversible damage were investigated in explanted CIED. No signs of malfunction were seen in any CIED after a total of 256 impacts up to 2000 N. Forces exceeding 1500 N reproducibly led to rib fractures of the porcine thorax, in line with previous reports describing serial rib fractures in humans at similar forces. One IS1/DF1 single-coil implantable cardioverter/defibrillator (ICD) lead was bent after an impact of 900 N; however, no signs of lead malfunction were noted on inspection and fluoroscopy. When testing explanted CIED to failure, only 4 of 16 CIEDs (25%) showed signs of damage on fluoroscopy. Two ICDs were unable to terminate VF despite reporting normal shock impedances before VF induction. Conclusion: This is the first study to analyse the effects of blunt force trauma on CIED. Our data suggest that CIED systems withstand contact sports impacts, which can result in serial rib fractures in humans. Therefore, general traumatological risks could outweigh the risks of CIED damage in sports with a low risk of collision. If damage is suspected, device interrogation should be performed.

Objective: Invasive multimodal fMRI in rodents is often compromised by susceptibility artifacts from adhesives used to secure cranial implants. We hypothesized that adhesive type, shape, and field strength significantly affect susceptibility artifacts, and systematically evaluated various adhesives. Materials and methods: Thirty-one adhesives were applied in constrained/unconstrained geometries and imaged with T2*-weighted EPI at 7.0 and 9.4 T to assess artifact depths. Spherical and flat patch shapes, both unconstrained geometries, were compared for artifact depth in vitro and in vivo. Adhesion strength was assessed on post-mortem mouse crania. Finally, an integrative scoring system rated adhesive properties, including artifact depth, handling, and adhesion strength. Results: Susceptibility artifacts were two times larger at 9.4 than at 7.0 T (p < 0.001), strongest at the patch edges, and deeper with spherical than flat patches (p < 0.05). Artifact size depended more on shape and volume after curing than adhesive type. Our integrative scoring system showed resins, bonding agents, and acrylics offered the best overall properties, while silicones and cements were less favorable. Discussion: Adhesive selection requires balancing handling, curing time, strength, and artifact depth. To minimize artifacts, adhesives should be applied in a spread-out, flat and thin layer. Our integrative scoring system supports classification of future classes of adhesives.