Posterior Olecranon Fracture Dislocations in Adults: A Systematic Review

Posterior olecranon fracture dislocations (POFDs) were considered posterior Monteggia lesions, which were less described in the literature. The purpose of this study was to provide a systematic review of the diagnosis, treatment, prognosis, and complications of POFDs in adults. A systematic review was performed to identify all relevant studies on the POFDs in the PubMed, Web of Science, Embase, and MEDLINE databases. The methodological quality of the studies was scored using the Methodological Index for Non‐Randomized Studies (MINORS). A total of 117 patients were identified in the nine studies selected. The high‐energy injuries accounted for 42.7% of the included studies. The rates of concomitant coronoid process, radial head fractures, and lateral collateral ligament injury were 84.6% (99/117), 87.2% (102/117), and 5% (6/117), respectively. The procedure was performed with a dorsal mid longitudinal approach to reconstruct all injury components. The postoperative clinical scores included the Broberg/Morrey rating, with a mean rating of excellent or good at 66%, the mean DASH score was 20.6, and the mean ASES score was 83. The flexion and extension arc and forearm rotation arcs were 100° and 134°, respectively. Complications included arthrosis in 28.2% (33/117) of cases, fracture nonunion or delayed union in 9.4% (11/117) of cases, heterotopic ossification in 7% (8/117) of cases, and the re‐operation rate was 16% (19/117). There was nearly no postoperative ulnohumeral instability. The main characteristics of POFDs were disruptions of the trochlear notch, including the olecranon and coronoid processes, and severe radial head fractures, while the lateral collateral ligament was spared. Although the POFDs had a low frequency of instability, the prognosis was relatively poor. The POFDs should be considered independently

Clinical outcomes of olecranon sled fixation in patients with Mayo type II olecranon fractures

Background: Tension band wiring and plate fixation are common internal fixation methods used for olecranon fractures, but complications and reoperations are common. The purpose of this study is to investigate the clinical outcomes of displaced olecranon fractures treated with olecranon sled internal fixation. Methods: The data of 39 patients with olecranon fractures treated with olecranon sled in the Department of Traumatology of Beijing Jishuitan Hospital between May 2018 and April 2020 were retrospectively analyzed. There were 17 males and 22 females; the mean age was 44.0 ± 15.8 (range, 18–68 years). Preoperative olecranon fractures were classified according to the Mayo classification: 24 cases were type IIA and 15 cases were type IIB. Elbow range of motion (extension and flexion) and forearm rotation (protonation and supination) were observed at the last follow-up. The Mayo elbow performance score (MEPS), Disabilities of the arm, shoulder and hand (DASH) and visual analogue scale (VAS) scores were used to evaluate elbow function and pain, and complications were also recorded. Results: Thirty-nine patients were followed up for 33.6 ± 8.3 months (range, 25–51 months) after the operation. At the last follow-up, the mean flexion-extension arc was 137° ± 15° (range, 60°–160°), and the mean pronation-supination arc was 178° ± 4° (range, 160°–180°). The mean MEPS was 94.9 ± 9.9 (range, 50.0–100.0). The mean DASH score was 5.4 ± 4.3 (range, 0–18.3). The mean VAS score was 0.4 ± 0.8 (range, 0–3). Seven patients developed olecranon skin irritation, and 3 of them had the internal fixation device removed. Two patients developed heterotopic ossification, of whom 1 patient suffered elbow stiffness. Conclusion: Olecranon sled internal fixation has good clinical outcomes in the treatment of Mayo type II olecranon fractures with a low rate of reoperations

Biomechanical comparison of three internal fixation configurations for low transcondylar fractures of the distal humerus

Background: We aimed to evaluate the biomechanical stiffness and strength of different internal fixa tion configurations and find suitable treatment strategies for low transcondylar fractures of the distal humerus.Methods and materials: Thirty 4th generation composite humeri were used to create low transcondy lar fracture models that were fixed by orthogonal and parallel double plates as well as posterolateral plate and medial screw (PPMS) configurations (n = 10 in each group) using an anatomical locking com pression plate screw system and fully threaded medial cortical screws. Posterior bending (maximum 50 N), axial loading (maximum 200 N) and internal rotation (maximum 10 Nmiddotm) were tested, in that order, for each specimen. Stiffness under different biomechanical settings among different configurations were compared. Another 18 sets of fracture models were created using these three configurations (n = 6 in each group) and the load to failure under axial loading among different configurations was compared.Results: Under posterior bending, the stiffness of parallel group was higher than orthogonal group (P 0.05). Under inter nal rotation, the stiffness of parallel group was higher than orthogonal group (P = 0.044), and orthogonal group was higher than PPMS group (P = 0.029). In failure test under axial loading, the load to failure in the orthogonal group was lower than parallel group (P = 0.009) and PPMS group (P = 0.021), but the differ ence between parallel group and PPMS group was not statistically significant (P > 0.05). All specimens in orthogonal group demonstrated distal medial failure; most specimens had distal medial and trochlear failure in the parallel group; most specimens exhibited contact failure in the PPMS group.Conclusion: For treating low transcondylar fractures, the overall stiffness and strength of the parallel configuration were superior to those of the orthogonal and PPMS configurations. Nevertheless, the PPMS configuration can provide adequate stability and stiffness comparable to double plate configurations un der axial loading. Therefore, the PPMS construct may have certain clinical value.(c) 2022 Published by Elsevier Ltd

Measurements of Secondary Organic Aerosol Formed from OH-initiated Photo-oxidation of Isoprene Using Online Photoionization Aerosol Mass Spectrometry

Isoprene is a significant source of atmospheric organic aerosol; however, the secondary organic aerosol (SOA) formation and involved chemical reaction pathways have remained to be elucidated. Recent works have shown that the photo-oxidation of isoprene leads to form SOA. In this study, the chemical composition of SOA from the OH-initiated photo-oxidation of isoprene, in the absence of seed aerosols, was investigated through the controlled laboratory chamber experiments. Thermal desorption/tunable vacuum-ultraviolet photoionization time-of-flight aerosol mass spectrometry (TD-VUV-TOF-PIAMS) was used in conjunction with the environmental chamber to study SOA formation. The mass spectra obtained at different photon energies and the photoionization efficiency (PIE) spectra of the SOA products can be obtained in real time. Aided by the ionization energies (IE) either from the ab initio calculations or the literatures, a number of SOA products were proposed. In addition to methacrolein, methyl vinyl ketone, and 3-methyl-furan, carbonyls, hydroxycarbonyls, nitrates, hydroxynitrates, and other oxygenated compounds in SOA formed in laboratory photo-oxiadation experiments were identified, some of them were investigated for the first time. Detailed chemical identification of SOA is crucial for understanding the photo-oxidation mechanisms of VOCs and the eventual formation of SOA. Possible reaction mechanisms will be discussed

Novel Biological Hydrogel: Swelling Behaviors Study in Salt Solutions with Different Ionic Valence Number

In this paper, poly γ-glutamic acid/ε-polylysine (γ-PGA/ε-PL) hydrogels were successful prepared. The γ-PGA/ε-PL hydrogels could be used to remove Na+, Ca2+, and Cr3+ from aqueous solution and were characterized by scanning electron microscopy. The performance of hydrogels were estimated under different ionic concentration, temperature, and pH. The results showed that the ionic concentration and the pH significantly influenced the swelling capacity of γ-PGA/ε-PL hydrogels. The swelling capacities of γ-PGA/ε-PL hydrogels were decreased with the increase of the ionic concentration. However, the swelling capacity of the γ-PGA/ε-PL hydrogel was increased with the increase of the pH. The swelling kinetics indicated that γ-PGA/ε-PL hydrogels presented a more limited swelling degree in metal ion solutions with higher ionic valence numbers than in ion solutions with lower ionic valence numbers. However, the swelling kinetics of γ-PGA/ε-PL hydrogels showed that they proposed a satisfactory description in NaCl and CaCl2 solutions. The adsorption process was fitted with a pseudo-second-order rate equation model. Moreover, the desorption kinetics of γ-PGA/ε-PL hydrogels showed that they could release most of the adsorption ions. Considering the biocompatibility, biodegradability, and ionic-sensitive properties, we propose that these γ-PGA/ε-PL hydrogels have high potential to be used in environmental protection, medical treatment, and other related fields