Plate fixation versus flexible intramedullary nails for management of closed femoral shaft fractures in the pediatric population: a systematic review and meta-analysis of the adverse outcomes

Purpose: Fractures of the femoral diaphysis are associated with a risk of morbidity in children. Various fixation methods have been developed, but with only limited evidence to support their use. This systematic review assesses the evidence regarding clinical outcomes of closed femoral diaphyseal fractures in children treated with plate fixation or flexible intramedullary nails. Methods: A PROSPERO-registered, PRISMA-compliant systematic review and meta-analysis were conducted. MEDLINE, Embase, and Web of Science (WoS) databases were searched from inception to February 2023. Inclusion criteria included clinical studies reporting adverse outcomes following surgical treatment of pediatric closed femoral diaphyseal fractures using plate fixation and flexible intramedullary nails. The ROBINS-I and RoB 2 tools evaluated the risk of bias. Results: Thirteen papers (2 prospective randomized controlled trials and 11 retrospective cohorts) reported 805 closed diaphyseal femoral fractures in 801 children (559 males, 242 females). There were 360 plate fixations and 445 flexible intramedullary nails. Two cases of osteomyelitis and one nonunion were reported. Meta-analysis showed that plate fixation had a lower risk of soft tissue infection (relative risk 0.26 (95% confidence interval 0.07–0.92)). There was no difference in the following outcomes: malunion (relative risk 0.68 (95% confidence interval 0.32–1.44)); unplanned reoperation (relative risk 0.59 (95% confidence interval 0.31–1.14)), and leg-length difference (relative risk 1.58 (95% confidence interval 0.66–3.77)). The risk of bias was high in all studies. Conclusions: An analysis of 805 fractures with minimal differences in meta-analyses is considered high quality even when the quality of the evidence is low. The findings are limited by important flaws in the methodology in the published literature. Well-designed multicentre prospective studies using standardized core outcomes are required to advise treatment recommendations. Level of evidence: III

Photon-Graviton Amplitudes from the Effective Action

We report on the status of an ongoing effort to calculate the complete one-loop low-energy effective actions in Einstein-Maxwell theory with a massive scalar or spinor loop, and to use them for obtaining the explicit form of the corresponding M-graviton/N-photon amplitudes. We present explicit results for the effective actions at the one-graviton four-photon level, and for the amplitudes at the one-graviton two-photon level. As expected on general grounds, these amplitudes relate in a simple way to the corresponding four-photon amplitudes. We also derive the gravitational Ward identity for the 1PI one-graviton -- N photon amplitude.Comment: 9 pages, 2 figures, talk given by C. Schubert at "Supersymmetries and Quantum Symmetries - SQS`2011", JINR Dubna, July 18 - 23, 2011 (to appear in the Proceedings

Radio-frequency dressing of Bose-Einstein condensates on an atom chip

The Bose-Einstein condensate (BEC) is a state of ultracold matter where many individual atoms form a single macroscopic quantum object, whose characteristics of constant phase across the cloud and calculable density make it an excellent device for probing quantum phenomena. Their applications range from answering fundamental questions on the quantum mechanical world, to quantum sensors for gravity and electrical current paths. The research comprising this thesis focuses on the observable relative quantum phase, which has direct implications on applications such as quantum sensors and quantum information.BECs are an ideal tool for exploring this; the phase of a BEC is not affected by the act of measurement, or time, allowing for interactions between multiple BECs. In order to study the transitive nature of relative quantum phase, one requires three or more BECs, and hence the development of a triple well potential on an atom chip using multiple radiofrequency (RF) dressing. The atom chip gives a high amount of tuneability and control over the trapping potential, for producing BECs with specific properties. Specific parameters of the trapping potential provide control over the phase, interaction strength of the atoms, and dimensionality of the BEC. Further, the addition of RF dressing fields allows for coherent splitting into multiple BECs, where the process of splitting has no effect on the phase.In this thesis, the design and implementation of single RF dressed adiabatic potentials on an atom chip, creating a double well, is experimentally realised, and coherent splitting is demonstrated with investigation of the relative quantum phase between two BECs. The realisation of multiple RF adiabatic potentials on an atom chip has not been achieved previously. This work explores the implementation of such potentials on the atom chip and discusses how the relative phases of three or more BECs can be studied.</p