Circumferential Cross-Stitch Suture for Longitudinal Lateral Meniscal Tear Around the Popliteal Tendon Hiatus Region.

Lateral meniscal repair of the popliteal hiatus is technically demanding. The inside-out technique requires an additional incision and carries the risk of posterolateral soft tissue damage to the knee joint. In addition, the presence of the popliteal tendon limits the route of the suture thread. Within the current trend of the all-inside suture technique, meniscal suture-based all-inside repair demonstrates biomechanical advantages over anchor-based all-inside repair. We introduce a meniscal suture-based all-inside meniscal repair technique for longitudinal lateral meniscal tears.

Fibular morphology is not associated with incidence of peroneal tendon dislocation.

PURPOSE: The association of peroneal tendon dislocation with peroneal bone morphology and postoperative redislocation rates remains unknown. This study compared the fibula morphology in patients with peroneal tendon dislocation with that in a control population. METHODS: The study enrolled 48 patients who underwent surgery for peroneal tendon dislocation at our institution during between 2018 and 2023. Thirty-five patients with preoperative magnetic resonance imaging of the ankle were defined as Group D and 35 with magnetic resonance imaging of the ankle for other reasons and with similar background data were selected as the control group (Group C). The posterior tilting angle of the fibula, posterolateral angle and posterolateral edge angle were evaluated at the plafond level. The posterior tilting angle, posterolateral angle and retromalleolar bone shape according to the Rosenberg classification (flat, convex, concave) were evaluated at the midpoint between the plafond and the tip. RESULTS: At the plafond level, the posterior tilting, posterolateral and posterolateral edge angles were 57.7 ± 11.1°, 123.8 ± 12.3° and 90.8 ± 13.7°, respectively, in Group D and 64.1 ± 15.4°, 121.1 ± 12.3° and 88.7 ± 12.2°, respectively, in Group C, with no significant differences. No significant between-group differences existed in the posterior tilting and posterolateral angles at the midpoint level. Moreover, no significant differences existed in distribution of the bone geometry according to the Rosenberg classification. CONCLUSION: There were no differences in morphology between patients with peroneal tendon dislocation and controls. This study provides useful information on the indications for primary surgery and whether bony approach is useful for peroneal tendon dislocation. LEVEL OF EVIDENCE: Level IV.

Single-cell trapping and retrieval in open microfluidics.

Among various single-cell analysis platforms, hydrodynamic cell trapping systems remain relevant because of their versatility. Among those, deterministic hydrodynamic cell-trapping systems have received significant interest; however, their applications are limited because trapped cells are kept within the closed microchannel, thus prohibiting access to external cell-picking devices. In this study, we develop a hydrodynamic cell-trapping system in an open microfluidics architecture to allow external access to trapped cells. A technique to render only the inside of a polydimethylsiloxane (PDMS) microchannel hydrophilic is developed, which allows the precise confinement of spontaneous capillary flow in the open-type microchannel with a width on the order of several tens of micrometers. Efficient trapping of single beads and single cells is achieved, in which trapped cells can be retrieved via automated robotic pipetting. The present system can facilitate the development of new single-cell analytical systems by bridging between microfluidic devices and macro-scale apparatus used in conventional biology.

Formation of topological defects at liquid/liquid crystal interfaces in micro-wells controlled by surfactants and light.

Topological defects, the fundamental entities arising from symmetry-breaking, have captivated the attention of physicists, mathematicians, and materials scientists for decades. Here we propose and demonstrate a novel method for robust control of topological defects in a liquid crystal (LC), an ideal testbed for the investigation of topological defects. A liquid layer is introduced on the LC in microwells in a microfluidic device. The liquid/LC interface facilitates the control of the LC alignment thereby introducing different molecules in the liquid/LC phase. A topological defect is robustly formed in a microwell when the liquid/LC interface and the microwell surface impose planar and homeotropic alignment, respectively. We also demonstrate the formation/disappearance of topological defects by light illumination, realized by dissolving photo-responsive molecules in the LC. Our platform that facilitates the control of LC topological defects by the introduction of different molecules and external stimuli could have potential for sensor applications.

Resource Allocation for Reconfigurable Intelligent Surface Assisted Dual Connectivity.

The next generation 6G wireless systems are envisioned to have higher reliability and capacity than the existing cellular systems. The reconfigurable intelligent surfaces (RISs)-assisted wireless networks are one of the promising solutions to control the wireless channel by altering the electromagnetic properties of the signal. The dual connectivity (DC) increases the per-user throughput by utilizing radio resources from two different base stations. In this work, we propose the RIS-assisted DC system to improve the per-user throughput of the users by utilizing resources from two base stations (BSs) in proximity via different RISs. Given an α-fair utility function, the joint resource allocation and the user scheduling of a RIS-assisted DC system is formulated as an optimization problem and the optimal user scheduling time fraction is derived. A heuristic is proposed to solve the formulated optimization problem with the derived optimal user scheduling time fractions. Exhaustive simulation results for coverage and throughput of the RIS-assisted DC system are presented with varying user, BS, blockage, and RIS densities for different fairness values. Further, we show that the proposed RIS-assisted DC system provides significant throughput gain of 52% and 48% in certain scenarios when compared to the existing benchmark and DC systems.

Traumatic injury of the third palmar interosseous muscle in a patient with dementia: A case report.

An 81-year-old man with dementia presented with a third palmar interosseous injury. A fourth flexor digitorum superficialis tendon transfer surgery was performed the following day. The patient achieved adduction of the little finger; however, flexion contracture that began 2 months after the surgery progressed until completion because of issues related to postoperative rehabilitation and home exercise. An injury of the third palmar interosseous muscle is extremely rare and is even more uncommon in older adults. Therefore, careful consideration must be given to determine whether surgery is the best choice, especially if the patient has dementia.

Postoperative subtype P as a risk factor for excessive postoperative sliding of cephalomedullary nail in femoral trochanteric fractures in old patients: A case series of 263 patients using computed tomography analysis.

INTRODUCTION: Although excellent results of cephalomedullary nailing for femoral trochanteric fractures have been reported, excessive sliding has recently been noted as a cause of lag screw cut-out. Excessive sliding is reported as sliding of ≥8mm, which occurs in approximately 40%of cases. This study aimed to evaluate the risk factors for excessive sliding. PATIENTS AND METHODS: Overall, 551 patients who underwent cephalomedullary nail surgery between 2016 and 2021 were recruited. Patients aged ≥65 years who underwent preoperative computed tomography (CT), experienced low-energy trauma, and received follow-up for >4 months were included. Cases were retrospectively reviewed for their postoperative sliding distance and the percentage of excessive sliding (>8 mm). 3D-CT classification, reduction pattern (subtypes A, N, and P) in the lateral view, medullary mismatch, and implant type (short/long Gamma3 nail and INTERTAN) were investigated fortheirimpact on sliding distance andtheincidence of excessive sliding. Complication rates (lag screw cut-out and non-union) were also assessed. RESULTS: Overall, 263 patients (mean age, 84.0±7.4; 186 women) were recruited. The median (range) sliding distance was 3.5 (0-20) mm, and 42 cases (16.0%) had excessive sliding. Sliding distance was significantly smaller in the 2-fragment group than in the 3-fragment group (GP+GA and GP+L) (p=0.02); however, there were no significant differences between the 2-fragment and other fracture-type groups, including the 3-fragment group (GP, GA, GP ± GA, GP ± L), 4-fragmentgroup(GP/L, GP ± L/GA, GP±GA/L), and 5-fragmentgroup. There was no significant difference in sliding distance according to postoperative reduction type between the groups (p=0.83) and no correlation between medullary mismatch and sliding distance. The amount of sliding and rate of excessive sliding were significantly lower in the INTERTAN group than in the Gamma3 nail groups (p<0.01). Logistic regression analysis with excessive sliding as the variable revealed reduction type P as the only risk factor (p=0.024, odds ratio 2.99). There were three lag screw cut-out (1.1%) cases and one non-union (0.4%) case. CONCLUSIONS: Postoperative subtype P is a risk factor for excessive sliding; there was significantly less sliding in the INTERTAN nail group. It is necessary to avoid reduction to subtype P to prevent postoperative excessive sliding. LEVEL OF EVIDENCE: IV.

Sarcomere Shortening of Pluripotent Stem Cell-Derived Cardiomyocytes using Fluorescent-Tagged Sarcomere Proteins.

Pluripotent stem cell-derived cardiomyocytes (PSC-CMs) can be produced from both embryonic and induced pluripotent stem (ES/iPS) cells. These cells provide promising sources for cardiac disease modeling. For cardiomyopathies, sarcomere shortening is one of the standard physiological assessments that are used with adult cardiomyocytes to examine their disease phenotypes. However, the available methods are not appropriate to assess the contractility of PSC-CMs, as these cells have underdeveloped sarcomeres that are invisible under phase-contrast microscopy. To address this issue and to perform sarcomere shortening with PSC-CMs, fluorescent-tagged sarcomere proteins and fluorescent live-imaging were used. Thin Z-lines and an M-line reside at both ends and the center of a sarcomere, respectively. Z-line proteins - α-Actinin (ACTN2), Telethonin (TCAP), and actin-associated LIM protein (PDLIM3) - and one M-line protein - Myomesin-2 (Myom2) - were tagged with fluorescent proteins. These tagged proteins can be expressed from endogenous alleles as knock-ins or from adeno-associated viruses (AAVs). Here, we introduce the methods to differentiate mouse and human pluripotent stem cells to cardiomyocytes, to produce AAVs, and to perform and analyze live-imaging. We also describe the methods for producing polydimethylsiloxane (PDMS) stamps for a patterned culture of PSC-CMs, which facilitates the analysis of sarcomere shortening with fluorescent-tagged proteins. To assess sarcomere shortening, time-lapse images of the beating cells were recorded at a high framerate (50-100 frames per second) under electrical stimulation (0.5-1 Hz). To analyze sarcomere length over the course of cell contraction, the recorded time-lapse images were subjected to SarcOptiM, a plug-in for ImageJ/Fiji. Our strategy provides a simple platform for investigating cardiac disease phenotypes in PSC-CMs.

Mitochondria are required for ATM activation by extranuclear oxidative stress in cultured human hepatoblastoma cell line Hep G2 cells.

Ataxia-telangiectasia mutated (ATM) is a serine/threonine protein kinase that plays a central role in DNA damage response (DDR). A recent study reported that oxidized ATM can be active in the absence of DDR. However, the issue of where ATM is activated by oxidative stress remains unclear. Regarding the localization of ATM, two possible locations, namely, mitochondria and peroxisomes are possible. We report herein that ATM can be activated when exposed to hydrogen peroxide without inducing nuclear DDR in Hep G2 cells, and the oxidized cells could be subjected to subcellular fractionation. The first detergent-based fractionation experiment revealed that active, phosphorylated ATM was located in the second fraction, which also contained both mitochondria and peroxisomes. An alternative fractionation method involving homogenization and differential centrifugation, which permits the light membrane fraction containing peroxisomes to be produced, but not mitochondria, revealed that the light membrane fraction contained only traces of ATM. In contrast, the heavy membrane fraction, which mainly contained mitochondrial components, was enriched in ATM and active ATM, suggesting that the oxidative activation of ATM occurs in mitochondria and not in peroxisomes. In Rho 0-Hep G2 cells, which lack mitochondrial DNA and functional mitochondria, ATM failed to respond to hydrogen peroxide, indicating that mitochondria are required for the oxidative activation of ATM. These findings strongly suggest that ATM can be activated in response to oxidative stress in mitochondria and that this occurs in a DDR-independent manner.