Correction of complex three-dimensional deformities at the proximal femur using indirect reduction with angle blade plate and patient-specific instruments: a technical note

Background Corrective osteotomies for complex proximal femoral deformities can be challenging; wherefore, subsidies in preoperative planning and during surgical procedures are considered helpful. Three-dimensional (3D) planning and patient-specific instruments (PSI) are already established in different orthopedic procedures. This study gives an overview on this technique at the proximal femur and proposes a new indirect reduction technique using an angle blade plate. Methods Using computed tomography (CT) data, 3D models are generated serving for the preoperative 3D planning. Different guides are used for registration of the planning to the intraoperative situation and to perform the desired osteotomies with the following reduction task. A new valuable tool to perform the correction is the use of a combined osteotomy and implant-positioning guide, with indirect deformity reduction over an angle blade plate. Results An overview of the advantages of 3D planning and the use of PSI in complex corrective osteotomies at the proximal femur is provided. Furthermore, a new technique with indirect deformity reduction over an angle blade plate is introduced. Conclusion Using 3D planning and PSI for complex corrective osteotomies at the proximal femur can be a useful tool in understanding the individual deformity and performing the aimed deformity reduction. The indirect reduction over the implant is a simple and valuable tool in achieving the desired correction, and concurrently, surgical exposure can be limited to a subvastus approach.

Retrograde Intramedullary Nailing for Proximal Monteggia Fractures in Children

IntroductionMonteggia fractures are defined as fractures of the ulna’s proximal third with associated dislocation of the radial head and were further described and classified by Bado. They are very rare in adults and even rare in children reaching an incidence of 1.5 - 3% of all pediatric forearm fractures. The treatment’s primary goal is the anatomical reduction of the ulnar fracture, and with that, the following indirect anatomic reduction of the radial head. Different modalities for the treatment of Monteggia fractures in children are reported.We present possible closed reduction techniques and internal fixation based on the type of Bado classification in pediatric patients. We illustrate these techniques as a case series discussing the strengths, risks, and pitfalls of the ulna’s retrograde nailing.Materials and MethodsFor this case series, we included all pediatric patients who got surgical treatment at our institution for a Monteggia lesion from November 2000 to August 2019. Preoperative imaging consisted of conventional radiographs of the elbow and the forearm in two planes. Results This case series reports about six pediatric cases (age two to six years, two girls and four boys). They all had a proximal Monteggia fracture. In all cases, closed indirect reduction of the ulnar fracture and reposition of the radial head was achieved utilizing retrograde nailing of the ulna employing an intramedullary nail or Kirschner-Wire according to the instructions. No infection, vascular or nerve injuries, or other complications occurred. All were pain-free and regained full range of motion compared to the contralateral side.ConclusionIndirect reduction and intramedullary retrograde nailing are minimally invasive techniques that do not harm the blood supply to the bone and soft tissues. It may be a safe and effective procedure.

Indirect Reduction of CO2 and Recycling of Polymers by Manganese-Catalyzed Transfer Hydrogenation of Amides, Carbamates, Urea Derivatives, and Polyurethanes

The reduction of polar bonds, in particular carbonyl groups, is of fundamental importance in organic chemistry and biology. Herein, we report a manganese pincer complex as a versatile catalyst for...

Finite Element Analysis of the Indirect Reduction of Posterior Pedicle Screw Fixation for a Thoracolumbar Burst Fracture

Background: Because burst fractures often involve damage to the column and posterior structures of the spine, the fracture block may invade the spinal canal and compress the spinal cord or the cauda equina, causing corresponding neurological dysfunction. When a thoracolumbar burst fracture is accompanied by the presence of bone in the spinal canal, whether posterior surgery requires spinal canal incision decompression remains controversial.Methods: Computed tomography (CT) images of the thoracolumbar spine of a 31-year-old male with an L1 burst fracture and Mimics 10.0 were used to establish a three-dimensional fracture model for simulating the indirect reduction process. The model was imported into Ansys 10.0, and a 1-10 mm displacement was loaded 10° behind the Z-axis on the upper endplate of the L1 vertebral body to simulate position reduction and open reduction. The displacement and stress changes in the intervertebral disc, fractured vertebral body and posterior longitudinal ligament were observed during reduction.Results: Under a displacement loaded 10° behind the Z-axis, the maximum stress in the vertebral body was concentrated on the upper disc of the injured vertebrae. The maximum displacement corresponded to the anterior edge of the vertebral body of the injured vertebrae, and the vertebral body height and the anterior lobes were essentially restored. When the displacement load was applied in the positive Z-axis direction, the maximum displacement corresponded to the posterior longitudinal ligament behind the injured vertebrae. Under a 6 mm load, the posterior longitudinal ligament displacement was 11.3 mm. Under an 8 mm load, this displacement significantly increased to 15.0 mm, and the vertebral stress was not concentrated on the intervertebral disc.Conclusions: The reduction of thoracolumbar burst fractures by positioning and distraction allowed the injured vertebrae to be restored to the normal height and kyphotic angle. The reduction of the posterior longitudinal ligament can move the bone block in the spinal canal into the reset space and yield good reset results.

Synthesis of Fe3O4/TiO2 Nanocomposite as Photocatalyst in Photoreduction Reaction of CO2 Conversion to Methanol

TiO2 modified Fe3O4 nanocomposite as photocatalyst in CO2 indirect reduction was synthesized by an ultrasonic-assisted sol-gel method and its photocatalytic activity was studied as well. The modification of the TiO2 composite was attempted to modify titanium dioxide to have better performance as a photocatalyst. Magnetite synthesis was carried out by the sono-coprecipitation method with the addition of the capping agent. The magnetite was coated with TiO2 via the sol-gel method under ultrasonic irradiation. The products were characterized by X-ray diffraction (XRD), Fourier transforms infrared spectrophotometry (FT-IR), transmission electron microscopy (TEM), and turbidimetry. The final product was also analyzed by diffuse reflectance UV-Visible (DR-UV) and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX). The product of indirect reduction was analyzed by gas chromatography-mass spectrometry (GC-MS). Photocatalytic reaction with Fe3O4/TiO2 nanocomposite produced a higher concentration of methanol than using TiO2. Methanol concentration produced from the photocatalytic reaction using TiO2 and Fe3O4/TiO2 was 6.63% and 16.82%.

Integrated Reduction of the Self–Reducing Pellets on the Blast Furnace

The objective of the present work is to research a quantitate ratio of degree direct reduction inside of SRP and degree of indirect reduction outside of SRP on the top of the blast furnace.The reactions of direct and indirect reduction occurring during the heat treatment of self reducing pellets (SRP) have been studied. In this investigation Blast furnace (BF) sludge which contains particles of coke, has been included in the SRP blend as a source of solid reductant and iron bearing oxides. In the SRP as a part ot the blast furnace burden occur the reactions simultaneously: inside of SRP-direct reduction by Csolid; gasification of carbon and indirect reduction by CO; and outside of SRP-indirect reduction of iron bearing oxides by reducing gas coming from the hearth of blast furnace through the column of charged materials. The experimental setup is shown in Fig. 1. It con-sists of a electrical heating furnace, which can be moved up and down. The quartz tube passes through the furnace. The reaction zone is in the middle of the furnace. Neutral argon atmosphere is created and for indirect reduction argon changed - on hydrogen. Gases of argon, hydrogen are introduced into the furnace separately. Wire of nickel alloy chromosome joins the scales test. A thermocouple is located in the tube.The crucible of wire chrome-nickel was permeable.Metohd. The experiments was performed continuously from the start temperature (~200 ˚C) to the experimental temperature (500 ˚C; 700 ˚C; 900 ˚C; 1100 ˚C) in argon free environment. Upon reaching the desired temperature argon was replaced by hydrogen during 30 minutes. After that the reduced probe of SRP was cooled in argon. Results. The integrated degree of reduction is equal 100%, which includes 98,6 % direct reduction by solid carbon under temperatures 1100°C. The chemical analysis of the reduced SRP showed the degree of integrated reduction change from 85,79 % (900 °C) to 92,50 % (1000 °C) and 84,6% (1100°C) and metallization 83,30 % (900 °C), 89,90 % (1000 °C), 80,75 % (1100 °C).These data correspond to results of degree of reduction SRP depends on temperature