In operando visualization of redox flow battery in membrane-free microfluidic platform.

Redox flow batteries (RFBs) are attractive large-scale energy storage techniques, achieving remarkable progress in performance enhancement for the last decades. Nevertheless, an in-depth understanding of the reaction mechanism still remains challenging due to its unique operation mechanism, where electrochemistry and hydrodynamics simultaneously govern battery performance. Thus, to elucidate the precise reactions occurring in RFB systems, an appropriate analysis technique that enables the real-time observation of electrokinetic phenomena is indispensable. Herein, we report in operando visualization and analytical study of RFBs by employing a membrane-free microfluidic platform, that is, a membrane-free microfluidic RFB. Using this platform, the electrokinetic investigations were carried out for the 5,10-bis(2-methoxyethyl)-5,10-dihydrophenazine (BMEPZ) catholyte, which has been recently proposed as a high-performance multiredox organic molecule. Taking advantage of the inherent colorimetric property of BMEPZ, we unravel the intrinsic electrochemical properties in terms of charge and mass transfer kinetics during the multiredox reaction through in operando visualization, which enables theoretical study of physicochemical hydrodynamics in electrochemical systems. Based on insights on the electrokinetic limitations in RFBs, we verify the validity of electrode geometry design that can suppress the range of the depletion region, leading to enhanced cell performance.

Investigation of Operational Parameters for Nanoelectrokinetic Purification and Preconcentration.

This work reports on experimental investigations into the operational parameters of nanoelectrokinetic purification and preconcentration, especially utilizing on ion concentration polarization (ICP). ICP as a nanoscale electrokinetic phenomenon has demonstrated promising advances in various fields utilizing an ion depletion zone (IDZ) with a steep electric field gradient inside the ICP layer. However, the inevitable electrokinetic instability occurring within the IDZ has posed a challenge in operating the ICP system stably. To address the need for a stable and efficient ICP operation in various devices and applications, we propose an operational strategy along with conducted research to determine optimal operating ranges. In order to investigate the operational parameters, a unit voltage (VTH) is introduced as the threshold for initiating ICP. We examined the applicability of VTH across various operating ranges to ensure its effectiveness and versatility. In ICP purification, we categorize three modes (steady, burst, and unsteady) based on IDZ expansion and stability under varying VTH and flow rate conditions, presenting optimal operational conditions that minimize the voltage margin. In ICP preconcentration, a systematic investigation is conducted to observe the influence of background electrolyte concentration and voltage conditions on preconcentration efficiency, offering insights into the correlation between preconcentration factor, electrical conditions, and preconcentration time. Therefore, this research would contribute to the practical understanding of nanoelectrokinetics, providing insight into experimental designs. These findings are expected to offer valuable guidance to researchers aiming to utilize ICP's potential across a spectrum of applications, from purification to preconcentration, in the realm of micro/nanofluidic systems.

Differential Impact of Surface Conduction and Electroosmotic Flow on Ion Transport Enhancement by Microscale Auxiliary Structures.

Our research investigates the impact of auxiliary structures on ion transport in electrochemical systems such as batteries and microscale desalination units, whose importance for sustainable development has increased dramatically in recent decades. The electrochemical systems typically feature ion-selective surfaces, such as electrodes and ion exchange membranes, where ion depletion can cause performance issues including metal dendrite formation and flow instability. Recent research has shown that auxiliary structures in these electrochemical systems can enhance ion transfer near ion-selective surfaces, thereby resolving the instability problem and improving the energy conversion efficiency of the system. Our study leverages recent advancements in nanoscale electrokinetics to model these auxiliary structures as pillar arrays near an ion exchange membrane in a microchannel. We examine how these structures enhance ion transports relative to the characteristic length scale of microchannel depth and pillars' proximity to the ion-selective surface. Results show that the effect of the pillars varies significantly with their placement. Specifically, in deeper microchannels, where electrokinetic convection is stronger, the closer the auxiliary structure is to the ion-selective membrane, the better the ion transfer. However, in the thinner microchannel, the proximity of the auxiliary structure to the ion selective membrane has a less significant correlation with the ion transfer. Therefore, this finding highlights the importance of spatial arrangement of the auxiliary structures in improving the performance of electrochemical devices. Conclusively, this study can help to better understand energy conversion systems such as fuel cells, salinity gradient power generation systems, and electrochemical desalination systems, where auxiliary structures can be used in the vicinity of ion-selective surfaces. Especially, our fundamental electrokinetic study provides an effective means for designing the efficient electrochemical platforms utilizing micro/nanofluidics.

Antimicrobial and anti-diabetic efficiency of Polyalthia longifolia leaf extracts and major compounds characterization.

This research was performed to investigate the bactericidal and fungicidal competence of extracts (methanol and petroleum ether extract) of Polyalthia longifolia leaf. Moreover, the major active compounds present in the effective crude extract (either methanol or petroleum ether extract) was determined through initially with UV-Vis spectra, FTIR, and GC-MS analyses. The methanol extract alone showed remarkable bactericidal and fungicidal activity against the bacterial (S. pyogenes > E. coli > S. aureus > S. pneumoniae > C. difficile > P. aeruginosa) and fungal (A. clavatus > C. albicans > A. niger > A. fumigatus > C. tropicalis > C. auris) pathogens at increased concentration (12.5 mg mL-1) than petroleum ether extract. The MIC and MBC values of methanol extract were found as 10-20 mg mL-1 and 30-40 mg mL-1 respectively. The MFC value of methanol extract was found as 10-20 mg mL-1. These MIC, MBC, and MFC values of methanol extract were considerably greater than petroleum ether extract. The FTIR and GC-MS characterization studies revealed that the presence of more acre functional groups belonging to bioactive compounds such as Z)-7-Hexadecenal, Aromandendrene, α-Curcumene, Caryophyllene, Methyl 14-methyl Pentadecanoat, Methyl trans-13-Octadecenoate, 9-Octadecenoic acid (Z)-, and 2-hydroxy-1- (hydroxymethyl)ethyl. As a result of these findings, it is possible that P. longifolia leaf methanol extract contains medicinally important bioactive substances with bactericidal and fungicidal properties.

Hierarchical Capillarity-Assisted Liquid Invasion in Multilayered Paper Channels for Nanoelectrokinetic Preconcentration.

A nanoelectrokinetic phenomenon called ion concentration polarization (ICP) has been recently applied to microfluidic paper-based devices for the high fold preconcentration of low-abundant analytes. The inherent microstructural characteristics of cellulose papers can sufficiently stabilize the chaotic electroconvection of ICP, which is a significant annoyance for typical engineered microfluidic channels. However, a high electrical voltage to induce ICP in a paper-fluidic channel can increase unavoidable electrophoretic forces over drag forces so that the preconcentrated plug is rapidly receded with severe dispersion. In order to enhance the hydraulic drag force that helps the preconcentration of analytes, here we introduce a multilayered paper structure into paper-fluidic channel. We theoretically and experimentally demonstrate that a hierarchical capillary structure in a multilayered paper-fluidic channel can effectively increase the hydraulic drag force. For the practical utility in the field of diagnostics, the mechanism is verified by a simple example of the immunoassay using biotin-streptavidin complexation.

dCas9-Mediated PCR-Free Detection of Oncogenic Mutation by Nonequilibrium Nanoelectrokinetic Selective Preconcentration.

Cutting-edge nanoelectrokinetic technology in this work provides a breakthrough for the present clinical demands of molecular diagnosis to detect a trace amount of oncogenic mutation of DNA in a short time without an erroneous PCR procedure. In this work, we combined the sequence-specific labeling scheme of CRISPR/dCas9 and ion concentration polarization (ICP) mechanism to separately preconcentrate target DNA molecules for rapid detection. Using the mobility shift caused by dCas9's specific binding to the mutant, the mutated DNA and normal DNA were distinguished in the microchip. Based on this technique, we successfully demonstrated the dCas9-mediated 1-min detection of single base substitution (SBS) in EGFR DNA, a carcinogenesis indicator. Moreover, the presence/absence of target DNA was identified at a glance like a commercial pregnancy test kit (two lines for positive and one line for negative) by the distinct preconcentration mechanisms of ICP, even at the 0.1% concentration of the target mutant.

Effects of prior antibiotic use on clarithromycin resistance in Helicobacter pylori.

BACKGROUND: Macrolide antibiotics are widely used to treat various infections such as pneumonia and sinusitis, and previous exposure to macrolides is presumed to be a risk factor for standard triple therapy failure in Helicobacter pylori (H. pylori) eradication. We aimed to determine whether previous use of macrolide antibiotics could affect clarithromycin resistance of H. pylori. MATERIALS AND METHODS: From the Korea National Health Insurance Service (NHIS2021-1-775) database, a total of 46,160 patients who were tested for clarithromycin resistance of H. pylori from 2016 to 2019 in Korea were identified. Their history of antibiotics in the past 10 years and history of respiratory comorbidity in the past 1 year were investigated. RESULTS: Clarithromycin resistance rate of H. pylori in Korea was 16.2%. A multivariate analysis revealed that female sex (OR: 1.472, p < .001), age > 50 years (OR: 1.340, p < .001), previous use of macrolide antibiotics (clarithromycin, OR: 2.902, p < .001; azithromycin, OR: 1.930, p < .001; erythromycin, OR: 2.060, p = .001; roxithromycin, OR: 2.022, p < .001), and history of respiratory comorbidity (sinusitis, OR: 1.271, p < .001; laryngopharyngitis, OR: 1.135, p = .032; bronchitis, OR: 1.245, p = .001; pneumonia, OR: 1.335, p = .026) were independent risk factors of clarithromycin resistance in H. pylori. CONCLUSIONS: The use of macrolide antibiotics and a recent diagnosis of respiratory disease might increase clarithromycin resistance of H. pylori.

Age, Tear Size, Extent of Retraction, and Fatty Infiltration Associated With a High Chance of a Similar Rotator Cuff Tear in the Contralateral Shoulder Regardless of Symptoms in Patients Undergoing Cuff Repair in the Index Shoulder.

PURPOSE: To investigate the prevalence of a contralateral rotator cuff tear (RCT) in patients with a symptomatic RCT requiring repair and to determine whether findings from magnetic resonance imaging (MRI) of the affected shoulder can predict the presence of a contralateral tear. METHODS: Patients with atraumatic RCTs who had undergone arthroscopic repair between March 2019 and February 2021 were reviewed in this study. MRI of both shoulder joints was performed to evaluate the bilaterality of RCT. Demographic factors and MRI findings of index shoulders were assessed using logistic regression analysis to reveal any correlations with the presence of RCT in the contralateral shoulder. RESULTS: A total of 428 patients were enrolled in this study. When the affected shoulders had a posterosuperior rotator cuff (PSRC) or subscapularis tear including either an isolated or combined tear, 63.6% and 67.8% had the same tears on the contralateral side, respectively. A contralateral-side tear was found in 74.6% (185/248) of symptomatic cases and 44.8% (65/145) of asymptomatic cases, which represents a significant difference (P < .001). Logistic regression analysis revealed that age ≥67.5 years, tear size ≥17 mm, Goutallier grade ≥1.5, and Patte grade ≥1.5 were found to be indicative of potential contralateral PSRC tears. By contrast, the presence of a subscapularis tear in the affected shoulder was the only significant risk factor in predicting a potential subscapularis tear in the contralateral shoulder. CONCLUSIONS: Among patients with a symptomatic RCT requiring arthroscopic repair, 63.6% with a PSRC tear and 67.8% with a subscapularis tear in the affected shoulder were found to have a similar tear in the contralateral shoulder regardless of symptoms. Age, tear size, extent of retraction, fatty infiltration of PSRC tears, and the presence of subscapularis tears were identified as factors predictive of tears on the contralateral side. LEVEL OF EVIDENCE: Level IV, case series.

Comparison of arthroscopic primary and revision Bankart repair for capsulolabral restoration: a matched-pair analysis.

INTRODUCTION: There have been no previous studies comparing serial radiologic results between primary and revision Bankart repair despite the significance of capsulolabral height and slope restoration. The purpose of this study was (1) to compare serially the height and slope of the repaired labrum in the early postoperative period among primary and revision Bankart repair groups, and (2) to compare clinical outcomes between the two groups. MATERIALS AND METHODS: This study included each 24 patients who underwent arthroscopic primary Bankart repair (Group A) and revision Bankart repair (Group B) matched by age, sex, and glenoid defect ratio. Postoperative serial radiologic assessment of the repaired labral height and slope was proceeded using magnetic resonance imaging (MRI) or computed tomographic arthrography (CTA) at 3 weeks and 6 months. RESULTS: There were no significant differences in labral height and slope at 3 weeks and 6 months postoperatively in Group A. However, significant reductions in labral height and slope were evident between 3 weeks and 6 months postoperatively in Group B (P < 0.05). Group A yielded superior results to Group B with respect to labral height and slope at each time point (P < 0.05) in between-group analyses. The clinical outcomes were not significantly different between the two groups except for the patients' return to their premorbid sports activity level (P = 0.024). CONCLUSIONS: The height and slope of the repaired capsulolabral structures in the early postoperative period after arthroscopic revision Bankart repair group were significantly lower than those of the primary Bankart repair group. Also the reduction of labral height and slope was significant in the revision Bankart repair group over time. Nonetheless, clinical outcomes did not differ significantly except return to premorbid sports activity level at final follow-up.

Early outcomes of complete excision followed by immediate postoperative single fractional 10 Gy for anterior chest keloids: A preliminary results.

Treatment of chest keloids is challenging. The aim of this study is to present our experience using surgical excision followed by postoperative single fractional 10 Gy radiotherapy for recurrent anterior chest keloids on the same day. 16 patients with recurrent anterior chest keloids were treated with complete excision followed by single-fractional 10 Gy radiotherapy within eight hours postoperatively. The mean follow-up period was 12 months. (10-14 months) The outcome was reported with a recurrence-free rate. We also reported side effects. The overall recurrence-free rate was 81.25%. The side effects were minimal, with two reported hyperpigmentation which was subsided after six months, and two cases of acute wound problems. Second malignancy or serious complications were not reported. Our preliminary results show positive outcomes of complete excision followed by postoperative single fractional 10 Gy radiotherapy for recurrent anterior chest keloids on the same day. Our current study needs further long-term validation with more diverse patients.

Relationship between freshwater harmful algal blooms and neurodegenerative disease incidence rates in South Korea.

BACKGROUND: Due to anthropogenic activities and global warming, the severity and distribution of harmful algal blooms (HABs) have been increasing steadily worldwide, including in South Korea (S. Korea). Previous studies reported that exposure to HABs could increase the risk of HAB-related diseases. However, very few studies examined the linkage between HABs and disease occurrence, particularly in S. Korea. The objective of this study was to evaluate the potential impact of HABs on neurodegenerative diseases (NDs), including Alzheimer's disease, Parkinson's disease, and motor neuron disease, at a population level. METHODS: Thirteen-year data (2005-2017) for chlorophyll-a (chl-a) concentrations as a bloom-related parameter, annual numbers of NDs, and population information were collected. First, the entire area of S. Korea was divided into a grid of 1 km, and the population number in each 1-km grid was collected using the Statistical Geographic Information Service Plus system. Cross-sectional time series data were analyzed with two statistical models, a generalized linear mixed model and a generalized linear model. RESULTS: The results show a general trend of increasing chl-a concentration and NDs year by year. We observed positive correlations between HAB intensity and the incidence rate of NDs. Particularly, HABs seem to have the most long-term carry-over effect on Parkinson's disease. Another key finding was that a 5-km radius from the HAB location was the boundary that showed the most significant associations with three NDs. CONCLUSIONS: This study provides statistical evidence that supports the potential risk of NDs from the exposure to HAB. Thus, it is recommended to monitor a broad spectrum of cyanotoxins, including neurotoxins, in bloom-affected regions in S. Korea and epidemiological studies in the future.

Epidemiology of Ankle Fractures in Korea: A Nationwide Population-Based Study.

BACKGROUND: Although ankle fractures are among the most common fractures, nationwide population-based data on the epidemiology of patients with ankle fractures are scarce. This study aimed to perform an epidemiological analysis of all ankle fractures in Korea from 2010 through 2018. METHODS: We used national registries from the Korean Health Insurance Review and Assessment Service from 2009 to 2018. The annual incidence of the ankle fracture was calculated. The incidence was also calculated according to gender and age. Trends of fracture subtypes were also analyzed. Then, the incidence of ankle fractures by seasonal variation was investigated. RESULTS: A total of 735,073 ankle fractures were identified in 461,497,758 people for 10 years. The annual incidence of ankle fracture was 171.37/100,000 persons in 2018, with a male to female ratio of 0.78. Interesting differences in the ankle fracture trends were observed between gender. Male shows the highest incidence in adolescence, and the even distribution has lasted for the rest of their lives. In females, the incidence of ankle fracture showed an increasing tendency as their age increased. There was a clear difference in the incidence rate of each season according to age. Ankle fractures occurred more in spring and autumn in children and adolescents and most in winter in the elderly. CONCLUSION: Ankle fracture risk was different between sex and exhibited seasonal variations. Our findings can be used for epidemiological awareness and prevention campaigns for ankle fractures.

Bone healing on serial plain radiographs occurs slowly but adequately after medial opening wedge high tibial osteotomy without bone graft.

PURPOSE: The purpose of this study was to prospectively investigate osteotomy gap filling rates on serial plain radiographs, and to evaluate whether alignment correction is maintained after medial opening wedge high tibial osteotomy (MOWHTO) using a locking plate without bone graft. METHODS: Between March 2014 and June 2017, MOWHTO was performed without bone graft regardless of gap size. Radiographs were taken preoperatively, postoperatively, at 1, 3, 6, 12, 18, and 24 months after surgery. Radiographic examinations included a weight bearing long-standing anteroposterior (AP) view of the whole lower extremity, as well as, the AP, lateral, and both oblique views of the knee. Bone healing was measured on the medial oblique view of the knee. The postoperative alignment correction and its maintenance were assessed using the three radiologic parameters of the weight-bearing line (WBL) ratio, the hip-knee-ankle angle (HKAA), and the medial proximal tibial angle (MPTA) on the weight-bearing long-standing AP view of the lower extremity. RESULTS: Fifty-two consecutive patients underwent MOWHTO, but three patients failed to follow-up for more than 24 months. A total of 49 patients were assessed in this study. The median opening gap height was 10.0 mm (IQR, 8.0-12.0; range, 7-20). On immediate post-operative radiographs, the mean gap filling was 31.4 ± 3.6%. After 1, 3, 6, 12, 18, and 24 months, the mean gap filling rates increased to 38.7 ± 4.4%, 51.4 ± 6.6%, 66.5 ± 5.1%, 84.8 ± 7.0%, 92.4 ± 5.6%, and 97.8 ± 2.3%, respectively. Statistical differences were observed between all the follow-up evaluations (P < 0.001). Statistical differences in the WBL ratio, HKAA, and MPTA were observed between preoperatively and 1 month after surgery (P < 0.001). The mean PTSA increased significantly from preoperatively to postoperatively (P < 0.001). However, no statistical differences were found between the post-operative follow-up radiographs performed for these four values. CONCLUSION: MOWHTO using a locking plate without bone graft achieved at least 90% bone healing and had no loss in correction at 2 years postoperatively. LEVEL OF EVIDENCE: III.

Overlimiting Current in Nonuniform Arrays of Microchannels: Recirculating Flow and Anticrystallization.

Overlimiting current (OLC) through electrolytes interfaced with perm-selective membranes has been extensively researched for understanding fundamental nano-electrokinetics and developing efficient engineering applications. This work studies how a network of microchannels in a nonuniform array, which mimics a natural pore configuration, can contribute to OLC. Here, micro/nanofluidic devices are fabricated with arrays of parallel microchannels with nonuniform size distributions, which are faced with a perm-selective membrane. All cases maintain the same surface and bulk conduction to allow probing of the sensitivity only by the nonuniformity. Rigorous experimental and theoretical investigation demonstrates that overlimiting conductance has a maximum value depending on the nonuniformity. Furthermore, in operando visualization reveals that the nonuniform arrays induce flow loops across the microchannel network enhancing advective transport. This recirculating flow eliminates local salt accumulations so that it can effectively suppress undesirable salt crystallization. Therefore, these results can significantly advance not only the fundamental understanding of the driving mechanism of the OLC but also the design rule of electrochemical membrane applications.

Electrokinetic-Driven Fast Ion Delivery for Reversible Aqueous Zinc Metal Batteries with High Capacity.

Aqueous zinc (Zn) metal batteries (ZMBs) are considered a promising candidate for grid-scale energy storage due to their freedom from fire hazards. However, a limited reversibility of Zn metal electrode caused by dendritic Zn growth has hindered the advent of high-capacity Zn metal batteries (>4 mAh cm-2 ). Herein, it is reported that fast electrokinetic Zn-ion transport extremely improves the Zn metal reversibility. It is revealed that a negatively charged porous layer (NPL) provides the electrokinetic Zn-ion transport by surface conduction, and consequently impedes the depletion of Zn-ion on electrode surface as indicated by numerical simulations and overlimiting current behavior. Due to the quick Zn-ion delivery, a dendrite-free and densely packed Zn metal deposit is accommodated inside its pores. With the introduction of the NPL, the cycling stability of Zn symmetric cell is enhanced by 21 times at 10 mA cm-2 /10 mAh cm-2 . Average Coulombic efficiency of 99.6% is achieved over 500 cycles for electrodeposition/stripping at 30 mA cm-2 /5 mAh cm-2 on NPL-Cu electrode. Furthermore, a high-capacity Zn/V2 O5 full cell with the NPL exhibits an extraordinary stability over 1000 cycles at a capacity of 4.8 mAh cm-2 .

An acquired plica-induced notch in the medial femoral condyle in a patient with medial patellar plica syndrome: a case report.

BACKGROUND: An inflamed and thickened medial patellar plica (MPP) caused by repeated mechanical irritation from trauma or overuse leads to impingement between the anterior medial femoral condyle and the medial articular facet of the patella and produces pain or clicking, which is known as MPP syndrome. In patients with MPP syndrome, cartilage damage may occur depending on the shape of the MPP and the duration of the impingement. CASE PRESENTATION: Preoperative magnetic resonance imaging in a 17-year-old male patient with MPP syndrome showed a hypertrophic MPP along with an abnormal notch in the articular surface of the medial femoral condyle. We considered that the impinged hypertrophic plica between the anterior medial femoral condyle and the medial articular facet of the patella resulted in cartilage damage on the articular surface of the medial femoral condyle. However, during arthroscopic surgery, we found that the cartilage of the notch, which was located beneath the MPP, was completely intact. We concluded that this abnormal notch had developed gradually in the MPP without cartilage damage. CONCLUSIONS: Surgeons should be mindful that acquired plica-induced notches in the articular surface of the medial femoral condyle can present in patients with MPP syndrome.

Lesion Size May Predict Return to Play in Young Elite Athletes Undergoing Microfracture for Osteochondral Lesions of the Talus.

PURPOSE: To evaluate the clinical and sports-related outcomes of arthroscopic microfracture (MFx) for osteochondral lesion of the talus (OLT) in elite athletes. METHODS: The athletes who underwent arthroscopic MFx for OLTs at our institution between January 2011 and September 2015 with minimum 2 years of follow-up were reviewed. The Foot and Ankle Outcome Score, American Orthopaedic Foot & Ankle Society, and visual analog scale pain score, time and rate of "return-to-competition" (RTC, return to an official match for at least 1 minute after treatment), and rate of "return-to-play" (RTP, participation in at least 2 entire seasons after treatment) were used to evaluate the outcomes. We compared athletes who were able to RTP with those who were not. RESULTS: In total, 41 patients (mean age 19.34 ± 3.76 years) were included. The mean follow-up was 54.9 ± 13.72 months. In total, 36 patients had medial lesions, and 5 patients had lateral lesions. All subscales of preoperative Foot and Ankle Outcome Score were significantly improved at the final follow-up. The mean preoperative American Orthopaedic Foot & Ankle Society score of 74.46 ± 8.10 improved to 91.62 ± 2.99 (P < .001) at the final follow-up. The mean preoperative visual analog scale pain score of 5.44 ± 1.57 improved to 2.66 ± 1.04 (P < .001). All patients achieved RTC (100%) at mean time of 5.45 ± 3.18 months, and 74.4% of patients were able to RTP. The RTP-group showed significantly smaller lesions compared to the No-RTP group (71.52 ± 43.29 vs 107.00 ± 45.28 mm2, P = .009). The cut-off OLT size for predicting RTP was 84.0 mm2, with a sensitivity of 90.0% and specificity of 75.9%. CONCLUSIONS: All athletes were able to RTC at average of 5.45 months after MFx for OLTs with minimal subchondral involvement, and 74.4% were able to RTP. The only prognostic variable for RTP was lesion size, and its predictive cut-off was 84.0 mm2. LEVEL OF EVIDENCE: IV, Case series.

Does an "Off-Track" Hill-Sachs Lesion That Is Misclassified as "Non-Engaging" Affect Outcomes From Bankart Repair Alone Compared With Bankart Repair Combined With Remplissage?

PURPOSE: To determine how intraoperative assessment (engagement test) may affect recurrent dislocation rate and to compare the clinical outcomes, recurrence rates, and presence of on-/off-track conditions between cases that received arthroscopic Bankart repair alone (nonengaged Hill-Sachs lesion) and Bankart repair with remplissage (engaged Hill-Sachs lesion). METHODS: We retrospectively reviewed 213 patients who underwent arthroscopic Bankart repair alone (186 patients with nonengaging lesions, group A) or with remplissage (27 patients with engaging lesion, group B) for recurrent anterior shoulder instability with <25% glenoid bone defect. The presence of an engaging Hill-Sachs lesion was determined during arthroscopic evaluation. On-track or off-track lesions were assessed retrospectively from preoperative 3-dimensional (3D) computed tomography (CT). RESULTS: Mean glenoid bone defect was 13.7% in group A and 20.7% in group B (P < .001). Off-track lesions were identified in 8.1% (15/186) and 100% (27/27) in group B. At the final follow-up (minimum 2 years; mean follow-up periods after surgery of 50.1 months in group A and 47.7 months in group B), there were no significant differences in shoulder functional scores and recurrence rates between groups, despite improvement after surgery. In the off-track lesion (group A-1: nonengaging but off-track lesion), recurrence instability occurred in 9 patients (60%, 9/15). Also, comparing group A-1 and group B, we noted significant differences in shoulder functional scores and recurrence rates (P < .001). CONCLUSION: Of 186 patients, 8.1% with nonengaging Hill-Sachs lesions during direct arthroscopic examination under anesthesia actually demonstrated off-track lesions on preoperative 3D CT scans retrospectively, with 60% experiencing recurrent instability. Intraoperative manual assessment for Hill-Sachs engagement was inferior to 3D CT scan in establishing the presence of off-track defects. LEVEL OF EVIDENCE: III, retrospective comparative study.

Shoulder outcome scoring systems have substantial ceiling effects 2 years after arthroscopic rotator cuff repair.

PURPOSE: Previous studies show no difference in clinical outcomes between patients with healed and structurally failed rotator cuff repairs. The objective of this study was to assess ceiling effects when reporting surgical outcomes of arthroscopic rotator cuff repair using four of the currently most popular clinical shoulder outcome scoring systems. METHODS: Ninety-two patients who underwent arthroscopic rotator cuff repair were examined. The simple shoulder test (SST), American Shoulder and Elbow Surgeons (ASES) score, University of California at Los Angeles (UCLA) shoulder rating scale, and Constant-Murley shoulder score were completed 2 years postoperatively. Demographic data of the subjects were analysed using descriptive statistics. The ceiling effects in the outcome data assessed for each scale were estimated based on two previously reported definitions. RESULTS: The number of patients with the maximum possible score was 31 (33.7%) with the SST, 26 (28.3%) with the ASES score, 28 (30.4%) with the UCLA scale, and 18 (19.6%) with the Constant-Murley score. The standardised distance of the outcome data assessed by the SST, ASES score, UCLA scale, and Constant-Murley scores were 0.92, 0.97, 0.96, and 1.18, respectively. CONCLUSION: The SST, ASES score, and UCLA scale evaluated at 2 years postoperatively have substantial ceiling effects showing that the proportion of patients with the maximum possible score is > 20%, and the standardised distance is < 1.0. Researchers should be aware of possible biases due to ceiling effects when interpreting the results of studies investigating the surgical outcomes of arthroscopic rotator cuff repair. It could increase the likelihood of a type II error. LEVEL OF EVIDENCE: IV.

Subscapularis re-tears associated with preoperative advanced fatty infiltration and greater subscapularis involvement, leading to inferior functional outcomes and decreased acromiohumeral distance.

PURPOSE: This study aimed to investigate the influence of repaired subscapularis integrity on midterm results for anterosuperior massive rotator cuff tears (MRCTs) treated with partial rotator cuff repair. METHODS: This study included 57 patients who underwent arthroscopic partial repair for an anterosuperior MRCT. They were assigned to the healed subscapularis group (Group H 37 patients) or subscapularis re-tear group (Group R 20 patients). Preoperative and postoperative functional scores and active ranges of motion (ROMs) were assessed. Preoperative and 6-month follow-up magnetic resonance arthrography (MRA)/computed tomography arthrography (CTA) images were compared between groups. RESULTS: At the final follow-up, mean functional shoulder scores including ROMs improved significantly in both groups compared to preoperative values (p < 0.001), except for forward flexion and internal rotation in Group R. All final functional values and ROMs (excluding external rotation) were better in Group H than in Group R (p < 0.001). Preoperative stage of fatty infiltration in the subscapularis muscle was significantly worse in Group R (p < 0.001). On follow-up MRA/CTA, the immediate residual defect after partial repair increased in 81% (30/37; mean, 17.8 mm) of patients in Group H and 100% (mean 24.6 mm) in Group R (p < 0.001). At final follow-up, mean acromiohumeral distance significantly decreased from 8.2 to 6.0 mm in Group H (p < 0.001) and from 8.3 to 4.9 mm in Group R (p < 0.001). There was a significant difference in final acromiohumeral distance between groups (p < 0.001). CONCLUSION: After a minimum 5-year follow-up after arthroscopic partial repair of anterosuperior MRCT, subscapularis re-tear was identified in 35% of patients (20/57) on early postoperative follow-up MRA/CTA. The subscapularis re-tear group exhibited more preoperative advanced fatty infiltration and greater extents of subscapularis involvement, which led to statistically inferior functional outcomes and decreased acromiohumeral distance at final follow-up. Nonetheless, in terms of a minimal clinically important difference, substantial clinical benefit, and patient-acceptable symptomatic state for clinical significance, there were no significant differences between the groups. LEVEL OF EVIDENCE: III.