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In order to observe the remodeling process of the inter-strand of the four-strand graft used for anterior cruciate ligament (ACL) reconstruction, and to find the histological and biomechanical influences on this process by braiding the four-strand graft, we conducted this study in a rabbit model. The rabbit's ACLs were reconstructed with bilateral four-strand semitendinous tendons which are in parallel or braided shape. The specimens of the two groups were collected at 3, 6, 12, 26 and 52 weeks after the operation. Gross and histological observations were done and the biomechanical properties of the specimens of the 26 and 52 weeks were compared. The result showed that in regular group, at 3 weeks, the strands which were in necrosis status were still separated with each other. At 6 weeks, the grafts were enveloped with hyperplastic synovium, some outer part of the gaps between strands were filled with synovium and fused together, while the inner parts were still separated. At 12 weeks, the graft was still in remodeling progress, but the remodeling degrees of each strand were different. Some strands had fused but some were still separated with "big" interval. At 26 and 52 weeks, some inter-strand gaps were hard to discriminate, some strands were connected with connective tissue and some separated ones still showed up. The braided ones manifested a similar but more synchronized remodeling process and showed a higher inter-strands fusing rate. The biomechanical test showed that the strength of the reconstructed ACL of the regular unbraided tendons was 36% of the contralateral normal ACL, while the braided ones reached 67%. The graft strengths of the specimen of the 26 and 52 weeks in the braided graft group were significantly higher than that of the unbraided group, while the stiffness of the 52-week specimen of the braided group was significantly higher than that of the unbraided group also. From this study, we concluded that as a graft for reconstruction of the ACL, the four-strand hamstring tendon needs to pass through the necrosis, revascularization, and ligamentation progress, but different strands were not in a synchronous process. The inter-strand gap may be completely fused, partial fused, fused but connected with connective tissue or still separated. By braiding the strands, the fusing percentage of the graft could be elevated and the biomechanical properties could be improved. [ABSTRACT FROM AUTHOR]

This study evaluated the MRI signal characteristics and MRI diagnostic accuracy in identifying completely healed menisci repaired with bioabsorbable arrows. A total of 34 patients (38 menisci), with a mean age of 26.0 years, underwent arthroscopic meniscal repair with bioabsorbable arrows and concomitant anterior cruciate ligament (ACL) reconstruction. Of the 34 patients, 27 were male and 7 were female. Of the 38 menisci, 27 were medial and 11 were lateral. Second-look arthroscopy was performed for each patient while taking out the hardware for ACL reconstruction of the tibial side to evaluate the healing status of the repaired menisci. Postoperative MRI was done 2 days before or after second-look arthroscopy. Sagittal T1, T2 and PD images and coronal T2 and PD images were used as the main diagnostic serials. Second-look arthroscopy showed that surfaces of the repaired sites of all 38 menici were almost smooth. In all 38 cases the tail ends of meniscus arrows disappeared and in four patients new overlying injury of compartmental cartilage at the repaired side was detected. MRI results revealed that different serials had different diagnostic accuracy. Sagittal: T1 28.9%, PD 34.2%, T2 60.5%. Coronal: PD 36.8%, T2 65.8%. The double sides Grade 3 signal had a higher proportion in saggital T1 and PD serials, 47.4 and 39.5%, respectively, while lower in sagittal and coronal T2 serials, both 5.3%. MRI diagnostic accuracy was correlated positively with the follow-up time (P < 0.05). MRI has its limitation in evaluating the status of menisci repaired with bioabsorbable arrows, especially for PD and T1 serials. T2 serials have higher diagnostic accuracy than other serials. MRI diagnostic accuracy can be improved by prolonging follow-up time and might be improved by further classifying Grade 3 signal in terms of signal intensity and the shape of the signal margin. [ABSTRACT FROM AUTHOR]

Biocatalysis is an attractive approach for the synthesis of chiral pharmaceuticals and fine chemicals, but assessing and/or improving the enantioselectivity of biocatalyst towards target substrates is often time and resource intensive. Although machine learning has been used to reveal the underlying relationship between protein sequences and biocatalytic enantioselectivity, the establishment of substrate fitness space is usually disregarded by chemists and is still a challenge. Using 240 datasets collected in our previous works, we adopt chemistry and geometry descriptors and build random forest classification models for predicting the enantioselectivity of amidase towards new substrates. We further propose a heuristic strategy based on these models, by which the rational protein engineering can be efficiently performed to synthesize chiral compounds with higher ee values, and the optimized variant results in a 53-fold higher E-value comparing to the wild-type amidase. This data-driven methodology is expected to broaden the application of machine learning in biocatalysis research., (© 2024. The Author(s).)

It has long been an aspirational goal to create artificial channel structures that replicate the feat achieved by ion channel proteins. Biological ion channels occasionally demonstrate multiple conductance states (known as subconductance), remaining a challenging property to achieve in artificial channel molecules. We report a funnel-shaped single-molecule channel constructed by an electron-deficient macrocycle and two electron-deficient aromatic imide arms. Planar lipid bilayer measurements reveal distinct current recordings, including a closed state, two conducting states, and spontaneous transitions between the three states, resembling the events seen in biological ion channels. The transitions result from conformational changes induced by chloride transport in the channel molecule. Both opening states show a non-linear and rectifying I-V relationship, indicating voltage-dependent transport due to the asymmetrical channel structure. This work could enhance our understanding of ion permeation and channel opening mechanism., (© 2024 Wiley-VCH GmbH.)

β-Branched aromatic α-amino acids are valuable building blocks in natural products and pharmaceutically active compounds. However, their chemical or enzymatic synthesis is challenging due to the presence of two stereocenters. We design phenylalanine ammonia lyases (PAL) variants for the direct asymmetric synthesis of β-branched aromatic α-amino acids. Based on extensive computational analyses, we unravel the enigma behind PAL's inability to accept β-methyl cinnamic acid (β-MeCA) as substrate and achieve the synthesis of the corresponding amino acids of β-MeCA and analogs using a double (PcPAL-L256V-I460V) and a triple mutant (PcPAL-F137V-L256V-I460V). The reactions are scaled-up using an optimized E. coli based whole-cell biotransformation system to produce ten β-branched phenylalanine analogs with high diastereoselectivity (dr > 20:1) and enantioselectivity (ee > 99.5%) in yields ranging from 41-71%. Moreover, we decipher the mechanism of PcPAL-L256V-I460V for the acceptance of β-MeCA and converting it with excellent stereoselectivity by computational simulations. Thus, this study offers an efficient method for synthesizing β-branched aromatic α-amino acids., (© 2024. The Author(s).)

Presented herein is the exploration of a novel non-covalent anion-carbonyl (X - ···C═O) interaction using aromatic imides as receptors and halides as lone pair donors. Combined theoretical calculations and experimental methods including 13 C NMR, IR, and crystallographic analyses were performed to provide the physical origin and experimental evidence of anion-carbonyl interactions. The EDA analysis (energy decomposition analysis) based on DFT calculation indicates that electrostatic terms are the dominant contributions for the binding energy while electron delocalization also significantly contributes alongside the electrostatic attraction. Orbital interaction (n → π*) involving the delocalization of halide lone pairs on the carbonyl antibonding orbitals was visualized with NBO (Natural Bond Orbital) analysis. 13 C NMR and IR spectra demonstrated upfield chemical shifts and red-shift frequency of hosts upon the addition of halides, reflecting the effect of orbital overlap between the halide lone pairs and π* of carbonyl (n → π* contribution). The anion-carbonyl interactions were directly revealed by X-ray structural analysis of anion and benzene triimide complexes.

Incorporation of privileged catalytic scaffolds into a macrocyclic skeleton represents an attractive strategy to furnish supramolecular catalysis systems with enzyme-mimetic cavity and multi-site cooperation. Herein we reported the synthesis, structure, binding properties and catalytic application of a series of chiral bis-phosphate macrocycles toward the challenging asymmetric electrophilic fluorination. With a large, integrated chiral cavity and two cooperative phosphate sites, these macrocycles exhibited good inclusion toward 1,4-diazabicyclo[2.2.2]octane (DABCO) dicationic ammoniums through complementary ion-pair and C-H⋅⋅⋅O interactions, as confirmed by crystallographic and solution binding studies. In fluorocyclization of tryptamines with Selectfluor reagent which has a similar DABCO-based dicationic structure, only 2 mol% macrocycle catalyst afforded the desired pyrroloindoline products in moderate yields and up to 91 % ee. For comparison, the acyclic mono-phosphate analogue gave obviously lower reactivity and enantioselectivity (<20 % ee), suggesting a remarkable macrocyclic effect. The high catalytic efficiency and superior stereocontrol were ascribed to the tight ion-pair binding and cavity-directed noncovalent interaction cooperation., (© 2024 Wiley-VCH GmbH.)

ClC is the main family of natural chloride channel proteins that transport Cl - across the cell membrane with high selectivity. The chloride transport and selectivity are determined by the hourglass-shaped pore and the filter located in the central and narrow region of the pore. Artificial unimolecular channel that mimics both the shape and function of the ClC selective pore is attractive, because it could provide simple molecular model to probe the intriguing mechanism and structure-function relevance of ClC. Here we elaborated upon the concept of molecular hourglass plus anion-π interactions for this purpose. The concept was validated by experimental results of molecular hourglasses using shape-persistent 1,3-alternate tetraoxacalix[2]arene[2]triazine as the central macrocyclic skeleton to control the conductance and selectivity, and anion-π interactions as the driving force to facilitate the chloride dehydration and movement along the channel., (© 2024 Wiley‐VCH GmbH.)

Protein engineering is essential for altering the substrate scope, catalytic activity and selectivity of enzymes for applications in biocatalysis. However, traditional approaches, such as directed evolution and rational design, encounter the challenge in dealing with the experimental screening process of a large protein mutation space. Machine learning methods allow the approximation of protein fitness landscapes and the identification of catalytic patterns using limited experimental data, thus providing a new avenue to guide protein engineering campaigns. In this concept article, we review machine learning models that have been developed to assess enzyme-substrate-catalysis performance relationships aiming to improve enzymes through data-driven protein engineering. Furthermore, we prospect the future development of this field to provide additional strategies and tools for achieving desired activities and selectivities., (© 2023 The Authors. ChemBioChem published by Wiley-VCH GmbH.)

Herein a series of chiral BTI radical anions bearing different chiral substituents were efficiently prepared by chemical reduction. X-ray crystallography revealed finely-tuned packing and helix assemblies of the radicals by the size of chiral substituents in crystalline state. In accordance with the crystalline-state packing, the powder ESR spectra indicate that 4 a - ⋅CoCp 2 + and 4 c - ⋅CoCp 2 + π-dimers exhibit thermally excited triplet states arising from strong spin-spin interactions, while discrete 4 b - ⋅CoCp 2 + shows a broad doublet-state signal reflecting weak spin-spin interactions. The interplay between the unpaired electron spin and chiral substituents was studied by UV-Vis-NIR spectra, electronic circular dichroism (ECD) and TD DFT calculations. Different NIR absorptions of the radicals attributing to isolated SOMO→LUMO+1 (~889 nm) transitions were recorded. The emergence of Cotton effects (CEs) at the NIR region for 4 c - ⋅CoCp 2 + radical enantiomers suggest the interplay between chirality and unpaired electron spin. The origin of the different circularly polarized light absorptions regarding SOMO derived transitions (around 880 nm) was attributed to chiral substitutes regulated electric and magnetic transition dipole moments of the unpaired electron participated transition., (© 2023 Wiley-VCH GmbH.)

An arm modification strategy, by replacing relatively rigid, electron-deficient side arms with flexible ether chain arms and linking them onto a tetraoxacalix[2]arene[2]triazine skeleton, was utilized to design an artificial molecular hourglass. The planar bilayer experiments confirmed the unimolecular channel mechanism and suggested reversed ion selectivity from the previously reported anion selectivity to weak cation selectivity.

Amine transaminases (ATAs) are powerful biocatalysts for the stereoselective synthesis of chiral amines. Machine learning provides a promising approach for protein engineering, but activity prediction models for ATAs remain elusive due to the difficulty of obtaining high-quality training data. Thus, we first created variants of the ATA from Ruegeria sp. (3FCR) with improved catalytic activity (up to 2000-fold) as well as reversed stereoselectivity by a structure-dependent rational design and collected a high-quality dataset in this process. Subsequently, we designed a modified one-hot code to describe steric and electronic effects of substrates and residues within ATAs. Finally, we built a gradient boosting regression tree predictor for catalytic activity and stereoselectivity, and applied this for the data-driven design of optimized variants which then showed improved activity (up to 3-fold compared to the best variants previously identified). We also demonstrated that the model can predict the catalytic activity for ATA variants of another origin by retraining with a small set of additional data., (© 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

Inspired by the unique structure and function of natural chloride channel (ClC) selectivity filter, we present herein the design of a ClC-type single channel molecule. This channel displays high ion transport activity with half-maximal effective concentration EC50 being 0.10 μM or 0.075 mol% (channel molecule to lipid ratio) determined by fluorescent analysis using lucigenin-encapsulated vesicles. Planar bilayer lipid membrane conductance measurements indicated an excellent Cl-/K+ selectivity with permeability ratio PCl-/PK+ up to 12.31, which is comparable with the chloride selectivity of natural ClC proteins. Moreover, high anion/anion selectivity (PCl-/PBr- = 66.21) and pH-dependent conductance and ion selectivity of channel molecule were also revealed. The ClC-like transport behaviours are contributed by the cooperation of hydrogen bonding and anion-π interactions in the central macrocyclic skeleton, and by the existence of pH-responsive terminal phenylalanine residues., (© 2023 Wiley-VCH GmbH.)

Purpose: The rapid development of winter sports requires investigation on injuries in Chongli district, Zhangjiakou city, one of the ski sites of the 2022 Winter Olympics. Careful evaluation is required to observe which injuries are caused under what circumstances, and then we can make corresponding preventive measures and recommendations based on the results., Methods: In this retrospective study, the data of injury cases at ski resorts in China (Chongli district) and Japan were analyzed to provide a reference for the ongoing injury prevention at ski resorts. We collected data on injuries at Wanlong and Fulong ski resorts in Chongli district during the 2017-2018 and 2018-2019 ski seasons. We referred to the skiing injury report issued in February 2020 of a nationwide ski safety statistical service - Japan Ski Safety Association. The causes of injury and specific injured body parts were analyzed based on the data of Chinese and Japanese ski resorts. Statistical significance has been calculated using the Chi-square test., Results: During the 2019-2020 ski season in Japanese ski resorts, the number of reported injuries per 10,000 skiers was 0.93, of which 457 (17.3%) were over 50 years old, accounting for a large proportion of injuries, meanwhile in Chongli ski resort, the injury rate of skiers aged 50 and over was 7.1%. The knee joint (23.7% at Wanlong ski resort and 28.4% in Japanese ski resorts) was the most injured body part among Chongli and Japanese skiers. Among snowboarders, shoulder joint injury (17.7% in Japanese ski resorts) was the most common, and injury on hands and fingers (16.3% in Wanlong ski resorts) was the most common. Head injury rates are similar in Chongli, China and Japanese ski resorts (8.2% and 8.7%, respectively)., Conclusion: Our analysis demonstrated that injury data recorded among young skiers was higher in Chinese ski resorts (Chongli district) than that in Japanese ski resorts, and elderly skiers made up a larger proportion of skiing injuries in Japanese resorts. Thus, according to our research, the protection of knee joints, shoulder joints, and hands and fingers should be taken seriously. It should pay attention to the teaching of ski poles (for finger protection), and use protective devices such as knee pads, helmets, etc., (Copyright © 2022. Production and hosting by Elsevier B.V.)

Towards unexplored intermolecular n→π* interactions, presented herein are the synthesis, structure, self-assembly and function of a multicarbonyl-containing macrocycle calix[2]arene[2]barbiturate 1. X-ray single crystal diffraction reveals the presence of Cl⋅⋅⋅C=O interactions in CH 2 Cl 2 ⊂1 host-guest complex and multiple intermolecular C=O⋅⋅⋅C=O interactions between molecules 1 in crystalline state. The intermolecular C=O⋅⋅⋅C=O interactions as attractive driving force led to unprecedented self-assembly of nanotube with diameter around 1.4 nm and inner surface engineered by aromatic rings. SEM and TEM images of the self-assembly of 1 demonstrated temperature-dependent morphologies which allows the observation of spheres at 25 °C and rods at 0 °C, respectively. XRD analysis indicated consistent hexagonal patterns in the self-assembly and single crystal lattice, indicating the nanotubes driven by C=O⋅⋅⋅C=O interactions constitute the basic structural architectures of both aggregates. The nanoscopic tubes (pores) formed in the rodlike single crystal engendering the separation of moving dyes were preliminarily investigated by a single-crystal chromatography and crystal-packed column chromatography., (© 2022 Wiley-VCH GmbH.)

Background: Balance training is the first choice of treatment for chronic ankle instability (CAI). However, there is a lack of research on the effects of balance training in CAI with generalized joint hypermobility (GJH). This study is to compare the outcomes of balance training in CAI patients with and without GJH., Methods: Forty CAI patients were assigned into the GJH group (Beighton ≥ 4, 20) and non-GJH group (Beighton < 4, 20) and they received same 3-month supervised balance training. Repeated measure ANOVA and independent t test were used to analyze self-reported questionnaires (Foot and ankle ability measure, FAAM), the number of patients experiencing ankle sprain, isokinetic muscle strength and postural control tests (Star excursion balance test, SEBT and Balance errors system, BES) before training, post-training immediately, and post-training 3 months, respectively., Results: At baseline, no differences were found between groups with except for GJH group having poorer SEBT in the posteromedial direction (83.6 ± 10.1 vs 92.8 ± 12.3, %) and in the posterolateral direction (84.7 ± 11.7 vs 95.7 ± 8.7, %). Following the balance training, GJH group demonstrated lower re-sprain ratio (immediately after training, 11.1% vs 23.5%, 3 month after training, 16.7% vs 29.4%) than non-GJH group, as well as greater FAAM-S score, plantarflexion strength and dorsiflexion strength at post-training immediately and 3 months, and both groups improved similarly in the FAAM-A score, muscle strength and balance control (SEBT in the posterior-lateral and posterior-medial directions, and BES scores) compared with baseline., Conclusions: CAI patients with GJH gained equally even better postural stability and muscle strength after the balance training than the non-GJH patients. Balance training could still be an effective treatment for CAI patients with GJH before considering surgery., Trial Registration: ChiCTR1900023999, June 21 st , 2019., (© 2023. The Author(s).)

Purpose: To evaluate the clinical outcomes of arthroscopically assisted double-bundle medial patellofemoral complex reconstruction (MPFC-R)., Methods: A retrospective review was carried out among adult patients who experienced at least 2 patellar dislocations and underwent primary arthroscopically assisted MPFC-R between January 2014 and November 2019. Dejour classification, tibial tubercle-trochlear groove (TT-TG) distance, and patellar height (with Insall-Salvati index) were measured. Pre- and postoperative patellar tilt were compared. Information on outcome scores, ability to return to sports, postoperative recurrent dislocations, and complications was recorded., Results: A total of 42 MPFC-Rs in 39 patients were included. Mean age at surgery was 22.2 ± 7.6 years; 69.2% of patients were female. Mean follow-up was 47.3 ± 20.2 months. Seventy-four percent of cases had Dejour B (19.0%), C (33.3%), and D (21.4%) trochlear dysplasia; mean TT-TG distance was 19.6 ± 3.5 mm, and mean Insall-Salvati index was 1.21 ± 0.17. Mean patellar tilt decreased from 27.6 ± 11.6° to 9.4 ± 6.5° (P < .001). All patients had statistically significant (P < .001) improvement in mean International Knee Documentation Committee (IKDC) (44.9 ± 18.2 to 87.5 ± 6.9), Lysholm (61.4 ± 16.6 to 94.1 ± 6.4), Kujala (56.0 ± 16.8 to 92.9 ± 5.3), and Tegner score (2.7 ± 1.3 to 4.6 ± 1.4). The majority of patients (96.9%) returned to sports, with 90.3% returning to the same or greater level of activity. No postoperative dislocations or subluxations were reported., Conclusions: Arthroscopically assisted double-bundle MPFC-R is a promising procedure to treat recurrent patellar instability at 2- to 7-year mid-term follow-up, despite the presence of trochlear dysplasia, elevated TT-TG distance and patellar alta. The improvement of IKDC score exceeded the minimal clinically important difference in 95.2% patients, and 66.7% surpassed the patient acceptable symptomatic state based on postoperative IKDC score with no redislocations being reported at latest follow-up., Level of Evidence: Level IV, case series, retrospective., (Copyright © 2022 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Xenon binding represents a formidable challenge, and efficient hosts remain rare. Here we report our findings that while enantiomeric bis(urea)-bis(thiourea) macrocycles form exclusive homochiral dimeric assemblies, xenon is able to overcome the narcissism and induces an otherwise-nonobservable heterochiral assembly as its preferred host. An experimental approach and fitting model were developed to obtain binding constants associated with the invisible assembly species. The determined xenon binding affinity with the heterochiral capsule reaches 1600 M -1 , which is 15 times higher than that with the homochiral capsule and represents the highest record for an assembled host. The origin of the large difference in xenon affinity between the two subtle diastereotopic assemblies was revealed by single-crystal analysis. In the heterochiral capsule with S 4 symmetry, the xenon atom is more tightly enclosed by van der Waals surroundings of the four thiourea groups arranged in a spherical cross-array, superior to the antiparallel array in the homochiral capsule with D 2 symmetry.

Amine transaminases (ATAs) are powerful biocatalysts for the stereoselective synthesis of chiral amines. However, wild-type ATAs usually show pH optima at slightly alkaline values and exhibit low catalytic activity under physiological conditions. For efficient asymmetric synthesis ATAs are commonly used in combination with lactate dehydrogenase (LDH, optimal pH: 7.5) and glucose dehydrogenase (GDH, optimal pH: 7.75) to shift the equilibrium towards the synthesis of the target chiral amine and hence their pH optima should fit to each other. Based on a protein structure alignment, variants of ( R )-selective transaminases were rationally designed, produced in E. coli , purified and subjected to biochemical characterization. This resulted in the discovery of the variant E49Q of the ATA from Aspergillus fumigatus , for which the pH optimum was successfully shifted from pH 8.5 to 7.5 and this variant furthermore had a two times higher specific activity than the wild-type protein at pH 7.5. A possible mechanism for this shift of the optimal pH is proposed. Asymmetric synthesis of ( R )-1-phenylethylamine from acetophenone in combination with LDH and GDH confirmed that the variant E49Q shows superior performance at pH 7.5 compared to the wild-type enzyme.

Background: Most of the research data of arthroscopic treatment for femoroacetabular impingement syndrome (FAIS) have been generated from Western populations., Purpose: To report the minimum 2-year follow-up results after hip arthroscopy for FAIS in Chinese patients., Study Design: Case series; Level of evidence, 4., Methods: A total of 434 hips that underwent primary hip arthroscopy for FAIS between 2016 and 2018 were included. Excluded were patients with previous ipsilateral hip surgery, ipsilateral surgery during the follow-up time, preoperative lateral center-edge angle <25°, Tönnis grade ≥2, sacroiliac joint disease, or incomplete preoperative radiographs or medical records. Preoperative and postoperative patient-reported outcomes (PROs; modified Harris Hip Score [mHHS], Hip Outcome Score-Activities of Daily Living [HOS-ADL], international Hip Outcome Tool, 12-component form [iHOT-12], and visual analog scale [VAS] for pain) were compared with the 2-tailed paired Student t test. Radiographic measures, intraoperative findings, performed procedures, complications, and revision surgery were also reported. The Spearman rank correlation was used to determine the association between patient characteristics and improvement in PRO scores., Results: Included were 272 hips with a mean follow-up of 39.4 ± 8.1 months. Overall, 243 hips (89.3%) underwent labral repair. The PROs from baseline to final follow-up were 64.7 to 90.0 for HOS-ADL, 41.1 to 73.4 for iHOT-12, 62.8 to 89.6 for mHHS, and 6.1 to 1.7 for VAS ( P < .001 for all). Younger age was correlated significantly with improved iHOT-12 scores ( r = -0.230; P < .001), and shorter symptom duration was significantly correlated with improved HOS-ADL ( r = -0.190; P = .003), iHOT-12 ( r = -0.146; P = .024), and VAS pain ( r = -0.143; P = .027) scores. The overall complication and revision hip arthroscopy rates were 4.0% and 3.3% respectively. At the final follow-up, no patient required conversion to total hip arthroplasty (THA)., Conclusion: At 2 years after hip arthroscopy for FAIS, Chinese patients demonstrated statistically significant improvement in PROs, with a low rate of revision surgery or conversion to THA. Shorter symptom duration and younger age were significantly positively correlated with improvement in PROs., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: This work was supported by funding from the National Natural Science Foundation of China (grants 82072403 and 81902205). AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto., (© The Author(s) 2022.)

The small Stokes shift and weak emission in the solid state are two main shortcomings associated with the boron-dipyrromethene (BODIPY) family of dyes. This study presents the design, synthesis and luminescent properties of boron difluoro complexes of 2-aryl-5-alkylamino-4-alkylaminocarbonylthiazoles. These dyes display Stokes shifts (Δλ, 77-101 nm) with quantum yields (ϕ FL ) up to 64.9 and 34.7 % in toluene solution and in solid state, respectively. Some of these compounds exhibit dual fluorescence and room-temperature phosphorescence (RTP) emission properties with modulable phosphorescence quantum yields (ϕ PL ) and lifetime (τ p up to 251 μs). The presence of intramolecular H-bonds and negligible π-π stacking revealed by X-ray crystal structure might account for the observed large Stokes shift and significant solid-state emission of these fluorophores, while the enhanced spin-orbit coupling (SOC) of iodine and the self-assembly driven by halogen bonding, π-π and C-H … π interactions could be responsible for the observed RTP of iodine containing phosphors., (© 2022 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

Purpose: To compare the clinical outcomes, rate of return to sports, postural control, and muscle strength between the arthroscopic and open modified Broström procedure for chronic lateral ankle instability (CLAI) patients., Methods: From September 2018 to April 2019, 70 patients diagnosed with CLAI were prospectively included with arthroscopic modified Broström procedure (n = 36) and open modified Broström procedure (n = 34). They were evaluated at five time points (preoperation and 3 months, 6 months, 1 year and 2 years postoperatively). The main results examined the rate of return to sports, American Orthopaedic Foot and Ankle Society Score (AOFAS), Foot and Ankle Ability Measure (FAAM), visual analogue scale (VAS), centre of pressure (COP) excursion velocity, time to boundary (TTB), plantar pressure, isokinetic muscle strength and complications., Results: Compared with the open group, the arthroscopic group demonstrated a significantly shorter period of return to the preinjury sport (13.2 ± 2.4 weeks vs. 18.7 ± 3.1 weeks, P = 0.023) and a higher early sport ratio (80.6 vs. 61.8%, P = 0.011) combined with better FAAM sports and AOFAS at 3 months and 6 months postoperatively and VAS at 3 months postoperatively. In addition, better anterior-posterior postural control stability, less time to peak force under lateral hindfoot and better dorsiflexion strength were shown in the arthroscopic group at 6 months postoperatively. No significant difference was found in clinical scores, posture control or muscle strength at the 1- or 2-year follow-up between the two groups., Conclusions: Shorter period and higher rates of return to sport activities and better clinical scores, posture control and muscle strength were achieved in the arthroscopic group at 6 months postoperatively, and no clinical differences were found between arthroscopic and open modified Broström procedure 1 year or 2 years postoperatively. Arthroscopic modified Broström procedure is a reliable procedure for CLAI injuries with the demand for fast exercise recovery., Clinical Registration: ChiCTR1900023999., Level of Evidence: II., (© 2022. The Author(s) under exclusive licence to European Society of Sports Traumatology, Knee Surgery, Arthroscopy (ESSKA).)

A new type of cage inherent chirality was accessed by hierarchical desymmetrization of a D 3 h -symmetric prismlike cage motif. The dissymmetric C 3 v cage precursor C1 bearing two different phloroglucinol caps was first synthesized. The subsequent progressive substitutions on the three triazine arms by different nucleophiles furnished the desired C 1 -symmetric inherently chiral cages C3 and C4 with rich structural diversity. Resolution of the racemic cages was achieved by chiral chromatography, and the enantiopure cages were readily obtained on the gram scale. Convenient post-synthetic transformations of the chiral cages with retention of enantiomeric purity were also realized. The absolute configuration was determined by X-ray crystallography, and a chirality descriptor was provided to define the cage chirality. With the inherently chiral array of the electron-deficient triazine surfaces constituting three individual chiral V-shaped π cavities, regio- and enantioselective anion-π binding was probed for the first time with minimum interference of other interactions. As exemplified with chiral phosphate anions (CPAs), it was found that cage (-)- C3a preferably binds ( S )-CPA - in the most electron-deficient cavity through synergistic anion-π interactions with considerable chiral selectivity.

Thermophilic polyester hydrolases (PES-H) have recently enabled biocatalytic recycling of the mass-produced synthetic polyester polyethylene terephthalate (PET), which has found widespread use in the packaging and textile industries. The growing demand for efficient PET hydrolases prompted us to solve high-resolution crystal structures of two metagenome-derived enzymes (PES-H1 and PES-H2) and notably also in complex with various PET substrate analogues. Structural analyses and computational modeling using molecular dynamics simulations provided an understanding of how product inhibition and multiple substrate binding modes influence key mechanistic steps of enzymatic PET hydrolysis. Key residues involved in substrate-binding and those identified previously as mutational hotspots in homologous enzymes were subjected to mutagenesis. At 72 °C, the L92F/Q94Y variant of PES-H1 exhibited 2.3-fold and 3.4-fold improved hydrolytic activity against amorphous PET films and pretreated real-world PET waste, respectively. The R204C/S250C variant of PES-H1 had a 6.4 °C higher melting temperature than the wild-type enzyme but retained similar hydrolytic activity. Under optimal reaction conditions, the L92F/Q94Y variant of PES-H1 hydrolyzed low-crystallinity PET materials 2.2-fold more efficiently than LCC ICCG, which was previously the most active PET hydrolase reported in the literature. This property makes the L92F/Q94Y variant of PES-H1 a good candidate for future applications in industrial plastic recycling processes., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

A series of tetraamino-bisthiourea chiral macrocycles containing two diarylthiourea and two chiral diamine units were synthesized by a fragment-coupling approach in high yields. Different chiral diamine units, including cyclohexanediamines and diphenylethanediamines were readily incorporated by both homo and hetero [1 + 1] macrocyclic condensation of bisamine and bisisothiocyanate fragments. With the easy synthesis, gram-scale of macrocycle products can be readily obtained. These chiral macrocycles were applied in catalyzing bioinspired decarboxylative Mannich reactions. Only 5 mol % of the optimal macrocycle catalyst efficiently catalyzed the decarboxylative addition of a broad scope of malonic acid half thioesters to isatin-derived ketimines with excellent yields and good enantioselectivity. The rigid macrocyclic framework and the cooperation between the thiourea and tertiary amine sites were found to be crucial for achieving efficient activation and stereocontrol. As shown in control experiments, catalysis with the acyclic analogues having the same structural motifs were non-selective., (Copyright © 2022, Guo et al.)

Herein we report an adaptive, achiral trithiourea molecular cage and its conformational and stereodynamics toward tricarboxylate anion binding. The cage was readily synthesized in four steps with a 44% yield for the irreversible cage-forming reaction. It possesses a flexible conformation and strongly binds 1,3,5-benzene tricarboxylate by forming a sandwich-like inclusion complex, with an affinity up to 10 6 M -1 in acetonitrile. Upon binding, the cage is locked in a twisted helical conformation. By incorporation of three chiral arms on the guest, a gear-like complex dominant in one given helical sense was produced. Due to the steric crowding in the helical grooves, a small change of methyl to ethyl on guest caused a striking difference on binding and chiral induction. The system thus represents a rare example of chiral induction on a flexible, achiral host and provides a decoupled model that the generation of a racemate and following chiral discrimination can be individually probed.

A series of triazine- and binaphthol-based homochiral and heterochiral macrocycles and cages were easily synthesized. Either fragment coupling or a one-pot approach afforded the desired products in 52-91% yields on a multigram scale as enantiopure forms. As disclosed by the crystal structures, these macrocycles and cages possess intriguing chiral cavities and assembly properties. In particular, ( S,S,S )- Cage features a D 3 -symmetric double-faced propeller-like structure with three chiral pockets at the side. It forms a highly ordered hexagonal column-like assembly and multiple distinct helical channels in its crystal.

This technical note describes an arthroscopic technique for treating delayed wound healing after Achilles tendon suture. Ankle arthroscopy is used to clean up the inflammatory tissues and foreign bodies that lead to delayed wound healing, with the advantages of simple postoperative care and low infection risk. This method may provide a less traumatic and low-risk option for the treatment of delayed wound healing after Achilles tendon surgery. The purpose of this technical note is to describe surgical procedures and related recommendations., (© 2021 The Authors.)

Background: To determine the effectiveness and sustainability of supervised balance training in people with chronic ankle instability (CAI) with grade III ligament injury., Methods: Twenty young adults (12 males and 8 females) diagnosed with CAI with grade III ligament injury underwent 3 months of supervised balance training. The self-reported functional questionnaire, plantar pressure (walking and single leg standing), and isokinetic ankle strength were consecutively evaluated at pre-training, 3 months, 6 months and one year. Paired T tests were used to explore changes in muscle strength and plantar pressures following the supervised balance training. According to whether the patient had sprain recurrence, the patients were divided into sprain recurrence group and control group. The risk factors of sprain recurrence were explored with univariate analysis and multivariable logistic regression., Results: The self-reported functional scores, the plantar pressure distribution and the muscle strength showed significant immediate improvements after 3 months of supervised balance training. At 6 months post-training, peak force under 2nd metatarsal, time to peak force under the medial hindfoot, time to boundary measurements and dorsiflexion, and eversion strength were partly declined to the pre-training level. 16 patients (80%) resumed the daily life and sports without sprain recurrence during the follow-up. Four patients (20%) reported ankle sprain during the follow-up, and the sprain recurrence group showed significantly higher Beighton scores (p = 0.012) and weaker initial inversion strength (p = 0.022) than the control group., Conclusions: Three months' of supervised balance training could effectively improve postural control and muscle strength of CAI cases with grade III ligament injury, although these improvements would partially deceased over time. Additional strength exercises for dorsiflexion and eversion should be supplemented from 6 months. Higher Beighton score and initial inversion muscle strength weakness might increase the risk of sprain recurrence., Trial Registration: ChiCTR, ChiCTR1900023999, Registered 21 June 2019, https://www.chictr.org.cn/edit.aspx?pid=39984&htm=4., (© 2022. The Author(s).)

Since its discovery two decades ago, anion-π interaction has been increasingly recognized as an important driving force. Extensive theoretical and experimental efforts on the ground-state anion-π binding and recognition have laid the bases for exploring its relevance in catalysis. Accordingly, the concept of "anion-π catalysis" that employing an electron-deficient π surface (π-acidic surface) for anionic reaction intermediate and transition state stabilization has emerged. This article shortly reviews the emergence and development of this concept, aiming to provide an emphasis on the general concept and key progress in this exciting area. To highlight the essential contribution of anion-π interactions, the contents are organized according to their role engaged in catalytic process, for example from both ground-state and transition-state stabilization to solely transition-state stabilization, mainly by a single π-face, and to cooperative π-face activation. A concluding remark and outlook on future development of this field is also given., (© 2021 Wiley-VCH GmbH.)

Purpose: To retrospectively analyze the clinical outcomes of meniscus repair with simultaneous anterior cruciate ligament (ACL) reconstruction and explore the causes of failure of meniscus repair., Methods: From May 2013 to July 2018, the clinical data of 165 patients who were treated with meniscus surgery and simultaneous ACL reconstruction, including 69 cases of meniscus repair (repair group) and 96 cases of partial meniscectomy (partial meniscectomy group) were retrospectively analyzed. The exclusion criteria were as follows: (1) ACL rupture associated with fracture, collateral ligament injury, or complex ligament injury; (2) a history of knee surgery; or (3) a significant degree of osteoarthritis. The 69 patients in the repair group were divided into the non-failure group (62 cases) and the failure group (7 cases) depending on the repair effect. Postoperative outcomes of the repair group and the partial meniscectomy group were compared. General conditions and postoperative outcomes of the failure group and the non-failure group were compared. During the median follow-up period of 28 months (range, 4 - 65 months) after the second arthroscopy, postoperative outcomes of seven patients in the failure group were summarized. SPSS 25.0 statistical software was used for statistical analysis. A p value less than 0.05 was considered statistically significant., Results: Seven patients in the failure group who underwent the second arthroscopy were followed up for (30 ± 17.4) months and their postoperative outcomes were summarized. Compared with the partial meniscectomy group, the International Knee Documentation Committee scores of patients in the repair group improved significantly (p = 0.031). Compared with the non-failure group, more patients in the failure group were younger than 24 years (p = 0.030). The median follow-up period was 39.5 months. All patients recovered well after subsequent partial meniscectomy and relieved clinical symptoms. Visual analog scale scores decreased significantly (p = 0.026), and the International Knee Documentation Committee and Lysholm scores improved significantly (p = 0.046 for both)., Conclusion: The failure rate of meniscus repair in this study was 10.1% (7/69), all of which were medial meniscus tears. However, the surgical outcomes of ACL reconstruction were not affected, and there might be a role for graft protection. Therefore, meniscus retears can be successful treated by performing subsequent partial meniscectomy in patients with repair failure., Competing Interests: Declaration of competing interest The authors have no conflicts of interest to declare., (Copyright © 2021 Chinese Medical Association. Production and hosting by Elsevier B.V. All rights reserved.)

Exploiting noncovalent π-interactions particularly emerging anion-π interactions to drive efficient catalysis is fascinating. Even with exciting progresses, can anion-π activation operate in water remains elusive. Here we report the design, synthesis and catalytic studies of a class of water-soluble electron-deficient molecular cages and relevant aromatic slide compounds. The prism-like cages contain three divided, long, cationic aromatic walls which constitute three highly electron-deficient V-shape cavities. They were efficiently synthesized in two steps from a parent triformyl cage in gram-scale. Crystal structure showed the π-walls bind to the counter bromide through strong anion-π interactions. Just 5 mol% of cages were effective in catalyzing decarboxylative Aldol reactions of aldehydes and malonic acid half thioesters in water but not in organic solvents, showing a pronounced hydrophobic amplification effect. Meantime, a series of single π-slides resembling the π-wall of the cage performed equally well, while those lacking an extended π-surface were ineffective, highlighting the essential role of electron-deficient π-face on promoting the conversion., (© 2021 Wiley-VCH GmbH.)

Here, we report an unprecedented catalytic enantioselective cyanation of ketonitrones enabled by the bifunctional cyanating reagent Me 2 (CH 2 Cl)SiCN. This approach allows facile access to optically active N -hydroxyl-α-amino nitriles that are of high synthetic value but difficult to acquire by other methods. The use of bifunctional cyanating reagent Me 2 (CH 2 Cl)SiCN not only achieves an enantioselectivity higher than that with TMSCN but also enables various diversification reactions of the resulting silylated adducts. This represents the first enantioselective catalytic nucleophilic addition reaction of unactivated ketone-derived nitrones, exhibiting the potential of such tetrasubstituted C═N bonds for asymmetric synthesis of N -hydroxy α-amino acids and other N -hydroxy tertiary amines.

Objective: To assess the mid-to-long term clinical outcomes after anterior cruciate ligament (ACL) revision surgery and to analyze their predictors., Methods: The medical records of 235 patients undergoing ACL revision surgery between Jan. 2001 and Dec. 2015 at Department of Sports Medicine, Peking University Third Hospital were reviewed. Data were collected including demographic information, information related to revision surgery (time and cause of graft failure, date of revision surgery, surgical technique, combined injuries and management, etc .), as well as information related to primary ACL reconstruction (time, cause and mechanism of first-time ACL rupture, date of primary ACL reconstruction, surgical technique, combined injuries and management, etc .). Patients were followed up at least 2 years after revision surgery for clinical outcomes [Tegner score, Lysholm score, and International Knee Documentation Committee (IKDC) subjective knee score]. Post-revision surgeries on the involved knee and the contralateral knee joint were also documented. Multivariate regression model was used to analyze the predictors of clinical outcomes after ACL revision surgery., Results: A total of 166 (70.63%) patients were followed up at a mean of (4.44±2.40) years (2.03-14.63 years). Clinical outcomes improved significantly at the last follow-up from pre-operative level, with the Lysholm, Tegner, and IKDC scores improving from 70.51±21.25, 3.39±1.77, 63.78±15.04 to 88.64±14.36, 4.67±1.739, 80.23±13.31 ( P < 0.05), respectively. Three (1.81%) patients experienced infection while 39 (23.49%) patients underwent surgery after revision surgery during the follow-up. Compared with that those occurred during sports, graft failure that occurred during daily activities or due to surgical technical errors that led to poorer clinical outcomes, with the Lysholm, Tegner, and IKDC scores of 9.90 (95% CI : 1.49-18.31), 1.41 (95% CI : 0.10-2.72), 10.35 (95% CI : 0.17-20.54), and 8.53 (95% CI : 1.31-15.75), 1.28 (95% CI : 0.14-2.43), 9.39 (95% CI : 1.03-17.74) lower, respectively. Compared with antero-medial portal, transtibial technique for placement of the femoral bone tunnel showed poorer Lysholm scores of 11.18 (95% CI : 4.73-17.63, P =0.001). Concurrent repair of medial meniscus yielded higher IKDC scores of 11.06 (95% CI : 1.21-20.92, P =0.029) than those with intact medical meniscus. Other factors showed no significant effect., Conclusion: ACL revision surgery is able to restore knee stability and improve knee function. Graft failure caused by sports, concurrent repair of medical meniscus and antero-medial portal technique predicts better outcomes after revision surgery.

Objective: To compare and analyze the difference between the injuries of recreational skiers in public ski resorts and those of skiing athletes in official competitions, and to explore the suggestions of medical insurance for these two types of skiers., Methods: The injury data of recreational skiers in Chongli District, Zhangjiakou City, Hebei Province during 2018-2019 and 2019-2020 snow seasons, and the injury data of skiers in two official international skiing competitions during 2019-2020 snow season and domestic test events in Chongli District of 2021 Winter Olympic Games were analyzed retrospectively, and the similarities and differences were compared., Results: A total of 1 187 injuries occurred to recreational skiers in the two public ski resorts during the 2018-2019 snow season, with an injury rate of 0.3%.There were 1 277 injury sites in total, and the most frequent injury sites were head and neck (230 cases, 18.0%), followed by knee joint (204 cases, 16.0%) and lower extremity (131 cases, 10.3%). Thirty-one skiers were injured in the two official international skiing competitions in the 2019-2020 and 2020-2021 snow season, and in the domestic test competitions in the 2021 Winter Olympic Games, and the injury rates were 11.5%, 17.2% and 12.0%, respectively. There were 37 injury sites in total, among which 11 (29.7%) were in the head and neck, followed by 6 (16.2%) in the knee joint and 5 (13.6%) in the chest, rib and abdomen., Conclusion: In order to better guarantee the safety of skiers and timely provide corresponding medical help, safety facilities and technical guidance should be added to the snow resort for leisure skiing, and medical stations should be set up in the snow resort. As the formal ski racing for skiing athletes during the game has 30 to 80 times higher injury ratesthan recreational skiers, and compared with the recreational skiing, head and neck injury rate is higher, and the damage is much heavier, more complete first aid facilities and experienced medical workers are, needed so the field should be equipped with the circuit inside the quantities, track fixed outside the clinic, surrounding referral hospitals set up trauma centers to provide athletes with more timely medical care.

Objective: To analyze the effects of visual restoration after cataract surgery on plantar pressure and biomechanics of foot in elder individuals., Methods: Thirty-two patients [male/female 5/27, (70.1±5.2) years old] with age-related cataract were recruited between October 2016 and December 2019. The footscan system was employed to record the data of plantar pressure during level walking before and 1-month after the cataract surgery. Parameters of peak pressure (PP), impulse (I), pressure-time integral (PTI) and time to peak pressure (TPP) from the regions of the 1st toe (T1), 2nd to 5th toes (T2-5), 1st to 5th metatarsal heads (M1-M5), midfoot (MF), medial hindfoot (HM) and lateral hindfoot (HL) were analyzed respectively., Results: Post-operatively, the visual function was effectively reconstructed with improved visual acuity in both eyes ( Z =-4.878, -4.801; P < 0.001). The PP ( t =2.266, P =0.031) and I ( t =2.152, P =0.039) values in M2 region on the dominant side (right foot) increased statistically at post-operative phase, while the changes of pressure and temporal para-meters in other regions remained stable. There was laterality in plantar pressure at pre-operative phase, manifested as greater PP values in M1, M2, MF, and HM regions on the dominant sides ( t =-2.414, -2.478, -2.144, -5.269; P < 0.05), greater PP values in T1, M3, M5 and HL regions on the non-dominant sides ( t =4.830, 3.155, 2.686, 3.683; P < 0.05), greater I values in M1, MF, and HM regions on the dominant sides ( t =-2.380, -2.185, -5.320; P < 0.05) and greater I values in T1, M3, M5 and HL regions on the non-dominant sides ( t =4.489, 2.247, 2.838, 3.992; P < 0.05). post-operatively, the pressure tended to be compatible between the two sides in regions of M3 and MF, while the magnitude of laterality in regions of M1 ( Z PP△ = -2.721, P =0.007; Z I△ =-2.581, P =0.010), M2 ( Z PP△ =-2.674, P =0.007; Z I△ =-2.375, P =0.018) and M5 ( Z PP△ =1.991, P =0.046; Z I△ =2.150, P =0.032) was further increased., Conclusion: Changes in plantar pressure after cataract surgery were characterized as increased pressure in the 2nd metatarsal head area on the dominant side. Visual restoration might intensify the laterality in the medial of forefoot on the dominant side and the lateral of forefoot on the non-dominant side.

Objective: To measure the electroencephalography (EEG) of the patients with anterior cruciate ligament (ACL) rupture when performing joint position perception movement task, to compare the differences between the ACL rupture side and the unaffected side, to identify the EEG change in the power spectrum caused by the ACL rupture, and to provide evidence for the diagnosis, treatment and rehabi-litation for ACL injury as well as knee instability., Methods: Sixteen male patients, selected from the Department of Sports Medicine, Peking University Third Hospital from November 2014 to April 2015, with only ACL rupture on one side used isokinetic muscle strength testing equipment were enrolled in the study to perform unilateral active knee joint positional movement and passive knee joint positional movement tasks. EEG was recorded to compare between the affected and unaffected limb of ACL rupture patients when doing single leg movement tasks, including passive knee joint position test and active knee joint position sensation test. The target position of the active knee joint position movement task and the passive knee joint position movement task was 30 degrees of knee flexion., Results: During the passive knee joint position test, there was no significant difference in EEG power spectrum of Delta[ F (1, 15)=0.003, P =0.957, η P 2 =0.001], Theta[ F (1, 15)=0.002, P =0.962, η P 2 < 0.001], Alpha[ F (1, 15)=0.002, P =0.966, η P 2 =0.001], Beta[ F (1, 15)=0.008, P =0.929, η P 2 =0.001] at Fz, Cz, and Pz between the affected and unaffected limbs in the ACL patients. During the active knee joint position movement task, the EEG power spectrum of Delta, Theta, Alpha, Beta at Fz and Cz location, on the affected side was significant higher than on the unaffected side., Conclusion: This study compared the differences between the ACL rupture side and the unaffected side during active knee position movement task and passive knee position movement task, and identifyied the EEG changes in the power spectrum caused by the ACL rupture, It was found that the central changes caused by unilateral ACL rupture still existed during contralateral (unaffected) side movement. The EEG power spectrum of the affected side during active exercise was significantly higher than that of the unaffected side This study provides new electrophysiological evidence for the study of ACL injury.

Objective: To summarize the experience in the diagnosis and management of septic arthritis after anterior cruciate ligament reconstruction., Methods: A retrospective review was conducted of all the arthroscopic anterior cruciate ligament reconstructions performed at Department of Sports Medicine, Peking University Third Hospital between January 2001 and December 2020. In the study, 65 of 27 867 patients experienced postoperative septic arthritis. The incidence, presentation, laboratory results, treatment, and outcome of all the infected patients were analyzed. The experiences of diagnosis and management of septic arthritis after anterior cruciate ligament reconstruction were summarized., Results: A total of 27 867 anterior cruciate ligament reconstructions were performed at our department between January 2001 and December 2020. In the study, 65 (0.23%) patients were identified with postoperative septic arthritis. The most common symptoms of the infected patients were fever (38.7±0.5) ℃, knee swelling, pain, and restricted motion. The mean peripheral white blood cell count (WBC) was (9.2±2.6)×10 9 /L (range 4.2×10 9 /L-19.4×10 9 /L), with (72.5±6.3) % (range 54.9%-85.1%) polymorphonuclear neutrophils (N). The mean erythrocyte sedimentation rate (ESR) was (59.9±24.1) mm/h (range 9-108 mm/h), C-reactive protein (CRP) was (10.9±5.7) mg/dL (range 1.2-30.8 mg/dL), and fibrinogen (FIB) level was (7.0±1.6) g/L (range 3.7-10.8 g/L). All of the laboratory results were statistically higher in the infection group compared with the normal postoperative group ( P ＜0.001). The synovial white blood cell count (SWBC) of aspirated knee joint fluid was (45.0±29.8)×10 9 /L (range 7.1×10 9 -76.5×10 9 /L). Polymorphonuclear cell percentage (PMNC) was (90.27±7.86) % (range 60%-97%). In the study, 45 patients (69.2%) had positive aspirate cultures. Microbiology showed coagulase-negative Staphylococcus (CNS) and Staphylococcus aureus (SA) were the most common bacterium (34 cases and 7 cases, individually). There were 26 methicillin-resistant Staphylococcus . Both conservative (16 patients) and operative (49 patients) treatments were effective, but conservative group had a longer recovery time (5.6 d vs. 1.6 d, P =0.042)., Conclusion: Septic arthritis after arthroscopic anterior cruciate ligament reconstruction is a rare but potentially devastating complication. The correct diagnosis relies on synovial fluid analysis and bacterial culture. Our proposed treatment protocol is arthroscopic debridement and antibiotic therapy as quickly as possible.

Objective: To explore the stress distribution characteristics of the graft after anterior cruciate ligament (ACL) reconstruction, so as to provide theoretical reference for the surgical plan of ACL reconstruction., Methods: Based on 3D MRI and CT images, finite element models of the uninjured knee joint and knee joint after ACL reconstruction were established in this study. The uninjured knee model included femur, tibia, fibula, medial collateral ligament, lateral collateral ligament, ACL and posterior cruciate ligament. The ACL reconstruction knee model included femur, tibia, fibula, medial collateral ligament, lateral collateral ligament, ACL graft and posterior cruciate ligament. Linear elastic material properties were used for both the uninjured and ACL reconstruction models. The elastic modulus of bone tissue was set as 17 GPa and Poisson' s ratio was 0.36. The material properties of ligament tissue and graft were set as elastic modulus 390 MPa and Poisson's ratio 0.4. The femur was fixed as the boundary condition, and the tibia anterior tension of 134 N was applied as the loading condition. The stress states of the ACL of the intact joint and the ACL graft after reconstruction were solved and analyzed, including tension, pressure, shear force and von Mises stress., Results: The maximum compressive stress (6.34 MPa), von Mises stress (5.9 MPa) and shear stress (1.83 MPa) of the reconstructed ACL graft were all at the anterior femoral end. It was consistent with the position of maximum compressive stress (8.77 MPa), von Mises stress (8.88 MPa) and shear stress (3.44 MPa) in the ACL of the intact knee joint. The maximum tensile stress of the graft also appeared at the femoral end, but at the posterior side, which was consistent with the position of the maximum tensile stress of ACL of the uninjured knee joint. More-over, the maximum tensile stress of the graft was only 0.88 MPa, which was less than 2.56 MPa of ACL of the uninjured knee joint., Conclusion: The maximum compressive stress, von Mises stress and shear stress of the ACL graft are located in the anterior femoral end, and the maximum tensile stress is located in the posterior femoral end, which is consistent with the position of the maximum tensile stress of the ACL of the uninjured knee joint. The anterior part of ACL and the graft bore higher stresses than the posterior part, which is consistent with the biomechanical characteristics of ACL.

Ion transport mediated by an ion pair receptor 1 bearing both cation and anion binding sites is presented. The ion pair binding property was revealed by means of 1 H NMR titrations in organic solutions and X-ray analysis in the solid state. Single crystal structures demonstrated that 1 and CaI 2 formed a solvent-separated ion-pair complex with two iodides each interacting with a triazine ring through anion-π interactions, whereas the calcium ion is bound by a pentaethylene glycol moiety. The ion transport activity was studied by monitoring the efflux of ions from salt-loaded EYPC large unilamellar vesicles (EYPC-LUVs) using ion selective electrodes. Chloride transport across the membrane mediated by the ion pair receptor through K + /Cl - or Na + /Cl - cotransport with a selectivity towards the K + /Cl - symport was realized.

Exploiting anion-π interactions in catalyst design is a fascinating direction to develop new and fundamental catalysis. For the appealing yet flexible π-face activation, can two or more π-acidic surfaces be manipulated for cooperative activation to achieve efficient transformation and particularly selectivity control is highly desirable. Here, we demonstrate a supramolecular π-catalysis strategy by establishing cooperative π-face activation in a confined electron-deficient cage cavity. The catalysts have a triazine based prism-like cage core and pendant chiral base sites. Only 2 mol % of cage catalyst efficiently catalyzed the decarboxylate Mannich reactions of sulfamate-headed cyclic aldimines and a series of malonic acid half thioesters in nearly quantitative yields and up to 97 % ee, enabling an unprecedent organocatalytic approach. The supramolecular π-cavity is essential in harnessing cooperative anion-π interactions for the efficient activation and excellent selectivity control., (© 2021 Wiley-VCH GmbH.)

Objective: To compare the clinical effects of arthroscopic lateral retinacular proximal release and "L" type release for lateral patellar compression syndrome. Methods: Sixty four lateral patellar compression syndrome (LPCS) patients were recruited who had arthroscopic surgery during September 2004 to January 2019 at Department of Sports Medicine,Peking University Third Hospital by the same group of doctors and a retrospective comparative study was conducted accordingly. Among them,24 cases underwent the traditional proximal release of lateral patellar retinaculum (traditional group),including 7 males and 17 females with an age of (42.9±14.6)years(range:23 to 72 years); 40 cases were treated with novel lateral retinacular release of "L" type release revised based on the previous experiences (novel group), consisting of 12 males and 28 females with an age of (54.9±13.1) years (range:28 to 76 years).All the patients participated surveys for the visual analogue scale (VAS),Lysholm score and International Knee Documentation Committee (IKDC) knee function subjective evaluation before and after the operation. The comparison of scores within groups was performed by Wilcoxon test,and comparison between groups was performed by Mann-Whitney U test and Chi-square test. Multivariate analysis was used to evaluate the related factors affecting each score. Results: The follow-up durations of traditional group and novel group were (12.6±1.0) years (range:11.7 to 15.3 years) and (2.2±1.0)years(range:1.0 to 4.4 years) respectively. At the last follow-up,VAS(0(1.0)to 6.0(2.0), Z =-5.471, P <0.01),Lysholm score(98.0(10.0)to 48.0(40.0), Z =-5.511, P <0.01),and IKDC score(82.8(11.2)to 37.4(18.5), Z =-5.444, P <0.01) in novel group were statistically significantly improved,and the postoperative excellent rate of Lysholm score was 97.5% in general. There was no significant difference in the changes of the three scores ( P >0.05) between the traditional group and the novel group. However,20.8% (5/24)patients in the traditional group reported significant weakness of the knee extension after surgery,while no such complain was received in the novel group ( P <0.01).The results of univariate analysis showed that surgical method was a related factor affecting the changes of VAS before and after surgery ( P <0.05).The results of multivariate analysis showed that whether or not with osteoarthritis and operation type were independent factors affecting the changes of Lysholm and IKDC scores ( P <0.05). Conclusions: The long-term effect of arthroscopic lateral retinacular release for the treatment of LPCS is satisfactory. Compared with the traditional proximal release surgery,the "L" type release can effectively avoid the complication of significant weakness of the knee extension significantly.

Background: Few studies have measured the dimensions of intercondylar notch under direct arthroscopic visualization. The purpose of our study was to analyse the association between time from anterior cruciate ligament (ACL) injury to reconstruction and the morphological changes of intercondylar notch using magnetic resonance imaging (MRI) and arthroscopy., Methods: Data was collected for patients who received knee arthroscopic surgery during 2014-2015. According to the time from ACL injury to reconstruction, these patients were divided into five groupsACL non-injured group (NI), acute rupture group (AR, <3 months), chronic rupture group 1 (CR1, 3-12 months), 2 (CR2, 1-5 years) and 3 (CR3, >5 years). MRI measurements of femoral condylar width (FCW) and intercondylar width (ICW) were undertaken before surgery. The widths at the base, middle and top of the intercondylar notch (ICWb, ICWm, ICWt, respectively) and the intercondylar notch height (ICH) were measured during arthroscopy. Intercondylar notch width index (NWI) and notch shape index (NSI) were then calculated and analysed among groups., Results: A total of 272 patients were allocated to groups NI (n = 89), AR (n = 84), CR1 (n = 51), CR2 (n = 30) or CR3 (n = 18). Statistical analysis showed significant differences in ICW, ICWb, ICH, NWI and NSI between groups NI and AR. Among the groups with ACL-injury, ICWb and ICWt and NWI in group CR3 were statistically smaller than the other three groups (P = 0.004, 0.016, and 0.005, respectively)., Conclusions: The width of intercondylar notch had a negative correlation with time from ACL injury to reconstruction. Significant secondary notch stenosis was observed over 5 years after ACL rupture., Competing Interests: Declaration of Competing Interest Each author certifies that neither he or she, nor any member of his or her immediate family, has funding or commercial associations (consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Objective: To make a retrospective analysis of the situation and process of treating skiers' injuries in the medical station of the Wanlong ski resort in Chongli and the nearest treatment hospital, and to provide a basis for the establishment and optimization of the treatment process between the medical station of the Winter Olympics ski resort and the nearest treatment hospital, and to gain experience for medical security of mass skiing., Methods: The data of all ski injuries in Chongli District were collected from the medical station of the Wanlong ski resort during the 2018-2019 snow season (November 2018 to April 2019) and the nearest treatment hospital during two periods (March 2019, and November 2019 to January 2020). The differences of injury causes, injury types, injury sites, and treatment effects of the injured skiers were analyzed., Results: A total of 755 cases of ski injuries were recorded in the medical station of Wanlong ski resort, the estimated incidence of injury was 2.02‰ per day. The nearest treatment hospital treated a total of 838 injured skiers from different ski resorts in Chongli District in the two periods. In the records of the ski resort medical station, the main causes of injury were technical defects and turnovers (53.6%). Knee joint injury rate was the highest (18.7%), followed by head and neck (12.9%) and lower limb (11.9%). The number of injuries on intermediate roads was the highest (40.0%), the greatest number of injuries (81.2%) occurred when the age of skiing was less than 5 years. In the records of the nearest treatment hospital, the injury types were fracture or fissure fracture, contusion and trauma, and muscle and soft tissue injury, accounting for 30.5%, 27.4%, and 21.2% respectively. 9.6% of the injured took the snow field ambulance to the hospital, and 50% of them suffered from fractures or fissure fractures., Conclusion: The injury rate of skiing in the 2018-2019 snow season of the Wanlong ski resort in Chongli was higher than that reported by foreign literature. Severe trauma (including severe fractures and concussions) could occur and patients needed to be transferred to the nearest hospital for treatment. The ski resort medical station and the nearest treatment hospital should be strengthened with adequate medical staff and equipment, and promote cooperation in the timely referral of seriously injured patients, the organization and construction of ski patrols and the medical security of large-scale competitions, thus playing an important role in forming a grassroots network of medical security and treatment system for skiing.

Background: The extracapsular subcutaneous endoscopic treatment is a new and under-researched approach to the endoscopic treatment of refractory lateral epicondylalgia. We aimed to introduce the techniques of the method and the mid-long term clinical effects. Furthermore, we intended to identify demographic and surgical-related factors correlated with prognosis of extracapsular subcutaneous method., Methods: Patients with a minimum of 6 months of conservative treatment for lateral epicondylalgia were recruited from March 2012 to July 2018. Key surgical techniques including microfracture and endoscopic suture were used. Visual analog scale (VAS), Mayo Elbow Performance Score (MEPS), and Disability of Arm (Shoulder and Hand, DASH) scores were used to evaluate clinical results. Univariable analysis and multivariable logistic regression were used to analyze effects of demographic characteristics and treatment techniques on prognosis., Results: Seventy-eight patients were treated with modified subcutaneous extracapsular surgery. No serious complications such as neurovascular injury or infection occurred. Postoperative VAS, MEPS, and DASH scores significantly improved (P<0.001). Age was associated with prognosis regarding VAS score (P=0.023). Older age was an independent relevant factor for poor prognosis regarding VAS score (OR =0.914, 95% CI: 0.842-0.993, P=0.033), and microfracture during surgery related to poor prognosis for DASH score (OR =0.056, 95% CI: 0.004-0.783, P=0.032). Plaster fixation was an independent factor related to good prognosis regarding DASH score (OR =11.156, 95% CI: 1.009-123.363, P=0.049)., Conclusions: Extracapsular subcutaneous method of refractory lateral epicondylalgia has satisfactory and stable clinical results with high safety. Techniques of extracapsular method include debridement, microfracture, and tendon suture under endoscope. Young age, no microfracture, and postoperative plaster fixation were associated with good long-term prognosis., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at http://dx.doi.org/10.21037/atm-20-6799). The authors have no conflicts of interest to declare., (2021 Annals of Translational Medicine. All rights reserved.)

Objective: To analyze characteristics and related factors of the plantar pressure during the level walking and single leg standing in the chronic ankle instability (CAI) individuals., Methods: From April 2019, 75 CAI individuals and 40 healthy individuals were enrolled in this study. Both of the static and dynamic plantar pressure were measured during six times level walking and three times single leg standing testing. The data including peak force, time to peak force in various foot contact areas and the time to boundary (TTB) and velocity of center of pressure (COP) were measured and compared between the affected side and the unaffected side and between the CAI cases and the healthy individuals. The correlations between the plantar pressure and the gender, Beighton score, affected side and body mass index (BMI) were analyzed., Results: The characteristics of plantar pressure distribution in the CAI individuals included: (1) During the level walking, the affected side showed the similar pressure contribution as the unaffected side ( P >0.05). While compared with healthy individuals, there was a significantly higher peak force in the 5th metatarsal area ( t =-3.86, P =0.03) of the affected side, lower peak force in the 1st ( t =2.99, P =0.02), 2nd metatarsal head areas ( t =2.09, P =0.01) of the affected side, medial hindfoot areas of both sides (affected, t =2.33, P =0.01; unaffected, t =3.74, P =0.02) and toes areass of both sides (affected, t =2.23, P =0.01; unaffected, t =3.28, P =0.02) and a delay to peak force in the 4th metatarsal head area ( t =3.33, P =0.01) of the affected side. (2) During the single leg standing, the CAI individuals showed significantly worse balance control in the anterior/posterior direction ( P < 0.05) and lateral/medial direction ( P < 0.05) compared with the healthy controls, and the affected side had more severe balance control deficit in the lateral/medial direction ( P < 0.05). (3) The women ( P < 0.05) and the individuals with higher Beighton scores ( P < 0.05) showed worse balance control deficit in the lateral/medial direction., Conclusion: CAI individuals showed significantly a more lateral shifted plantar distribution during the level walking compared with the healthy individuals and the tendency was worse on the affected sides, and showed worse balance control in the anterior/posterior direction and lateral/medial direction during the single leg standing. The women and those with generalized ligament laxity showed significantly worse balance control.

Background: A well-established reference is lacking for diagnosing lateral patellar compression syndrome (LPCS), and this diagnosis currently depends on clinicians' subjective judgment and several examination results. X-rays are primarily used to diagnose LPCS, but they have low detection rates of patellar tilt using the congruence angle (CA) and patellar tilting angle (PTA)., Methods: We enrolled 87 patients (31 men and 56 women; mean age: 42.11±15.33 years) between 2016 and 2019 and divided them as per diagnosis into three groups of 29 each: LPCS, patellar dislocation (PD, control), and meniscus tear (MT, negative control) groups. A senior radiologist and the chief physician of sports medicine examined their patellar axial radiographs of the knee in 30° flexion using a computer imaging system, measuring LPCA, CA and PTA. Univariate analysis of variance and Kruskal-Wallis H test were used to compare measurement data with normal distribution and non-normal distribution, respectively. Bonferroni correction was used to analyze different indicators for different groups. The area under the curve (AUC) was calculated to verify the value of LPCA in the initial diagnosis of LPCS., Results: LPCA (19.88±7.49) was significantly higher in LPCS group than in MT (13.68±4.69) and PD groups (10.16±4.43) (P<0.01) and was also significantly higher on affected side than on healthy side (16.44±5.00) (P=0.04). LPCA >13.9° had sensitivity and specificity of 89.66% and 68.97%, respectively, for LPCS diagnosis (AUC: 0.82, 95% confidence interval: 0.719-0.891, P<0.001)., Conclusions: We demonstrated that LPCA measured using an axial patellar radiograph of the knee in 30° flexion is high in patients with LPCS, and it may be used for diagnosing LPCS., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at http://dx.doi.org/10.21037/atm-20-6410). The authors have no conflicts of interest to declare., (2021 Annals of Translational Medicine. All rights reserved.)

BACKGROUND The interosseous talocalcaneal ligament (ITCL) is the main soft-tissue contributor to subtalar joint stability. The role of ITCL reconstruction in retaining this stability is minimally reported. Therefore, we conducted this study to investigate the effects of rupture and reconstruction of the ITCL on the subtalar and peritalar joints. MATERIAL AND METHODS This experimental study randomly divided 72 rabbits into 3 equal groups of 24 rabbits each. Group I underwent reconstruction surgery, group II underwent resection, and group III was the control group. The cartilages between the talocrural and calcaneocrural joints, and between the subtalar and talonavicular joints on both sides were assessed by gross observation, ink staining, histology, and immunohistochemistry at weeks 4, 8, 16, and 32, postoperatively. RESULTS In group II, the quantitative ink staining analysis revealed degeneration of the articular cartilages on the talonavicular joint (T=2.070, P=0.038) and the posterior subtalar joint (T=2.121, P=0.034) compared with the 2 sides of the same rabbit at 4 and 8 postoperative weeks. Comparing the operated sides of all the groups showed the posterior subtalar joints (Hc=9.563, P=0.008) and talonavicular joints (Hc=9.714, P=0.008) had an obvious difference at postoperative week 4; and in the calcaneocrural joints (Hc=6.750, P=0.034), it was noticed at postoperative week 8. Histology and immunohistochemistry findings confirm these observations. CONCLUSIONS An ITCL resection can lead to the progressive degeneration of the talonavicular and posterior subtalar joints, while an ITCL reconstruction can be beneficial in restoring the stability of these joints, preventing or postponing their degeneration, and protecting the articular cartilages.

Xenon binding has attracted interest due to the potential for xenon separation and emerging applications in magnetic resonance imaging. Compared to their covalent counterparts, assembled hosts that are able to effectively bind xenon are rare. Here, we report a tight yet soft chiral macrocycle dimeric capsule for efficient and adaptive xenon binding in both crystal form and solution. The chiral bisurea-bisthiourea macrocycle can be easily synthesized in multi-gram scale. Through assembly, the flexible macrocycles are locked in a bowl-shaped conformation and buckled to each other, wrapping up a tight, completely sealed yet adjustable cavity suitable for xenon, with a very high affinity for an assembled host. A slow-exchange process and drastic spectral changes are observed in both 1 H and 129 Xe NMR. With the easy synthesis, modification and reversible characteristics, we believe the robust yet adaptive assembly system may find applications in xenon sequestration and magnetic resonance imaging-based biosensing.