BACKGROUND: This study evaluated the effect of head rotation on the first-attempt success rate of i-gel insertion, aiming to alleviate the effect of gravity on the tongue and reduce resistance between the device and the tongue.
METHODS: Adult surgical patients were randomized to standard and head rotation technique groups. In the head rotation technique group, patients\' heads were maximally rotated to the left before i-gel insertion. The primary endpoint was the first-attempt success rate. Secondary endpoints included the success rate within two attempts (using the allocated technique), time required for successful i-gel placement within two attempts, and success rate at the third attempt (using the opposite technique).
RESULTS: Among 158 patients, the head rotation technique group showed a significantly higher first-attempt success rate (60/80, 75.0%) compared to the standard technique group (45/78, 57.7%; P = 0.021). The success rate within two attempts was similar between the groups (95.0% vs. 91.0%, P = 0.326). The time required for successful i-gel placement was significantly shorter in the head rotation technique (mean [SD], 13.4 [3.7] s vs. 16.3 [7.8] s; P = 0.030). When the head rotation technique failed, the standard technique also failed in all cases (n = 4), whereas the head rotation technique succeeded in five out of the seven patients where the standard technique failed.
CONCLUSIONS: The head rotation technique significantly improved the first-attempt success rate and reduced the time required for successful i-gel insertion. It was effective when the standard technique failed. The head rotation technique may be an effective primary or alternative method for i-gel insertion.
BACKGROUND: ClinicalTrials.gov (NCT05201339).

In total hip arthroplasty (THA), determining the center of rotation (COR) and diameter of the hip joint (acetabulum and femoral head) is essential to restore patient biomechanics. This study investigates on-the-fly determination of hip COR and size, using off-the-shelf augmented reality (AR) hardware. An AR head-mounted device (HMD) was configured with inside-out infrared tracking enabling the determination of surface coordinates using a handheld stylus. Two investigators examined 10 prosthetic femoral heads and cups, and 10 human femurs. The HMD calculated the diameter and COR through sphere fitting. Results were compared to data obtained from either verified prosthetic geometry or post-hoc CT analysis. Repeated single-observer measurements showed a mean diameter error of 0.63 mm ± 0.48 mm for the prosthetic heads and 0.54 mm ± 0.39 mm for the cups. Inter-observer comparison yielded mean diameter errors of 0.28 mm ± 0.71 mm and 1.82 mm ± 1.42 mm for the heads and cups, respectively. Cadaver testing found a mean COR error of 3.09 mm ± 1.18 mm and a diameter error of 1.10 mm ± 0.90 mm. Intra- and inter-observer reliability averaged below 2 mm. AR-based surface mapping using HMD proved accurate and reliable in determining the diameter of THA components with promise in identifying COR and diameter of osteoarthritic femoral heads.

We present the case of a 65-year-old man with bilateral keratoconus and history of bilateral penetrating keratoplasty (PK) who developed gradual visual decline in the left eye due to cataract formation. Following successful left eye cataract surgery and monofocal, non-toric intraocular lens (IOL) in-the-bag implantation, the patient experienced persistently low uncorrected distance visual acuity (UDVA) due to high residual refractive error and intolerance to contact lenses. A supplementary toric IOL was placed in the ciliary sulcus, but subsequent rotational instability of the lens required repeated realignment. Despite two attempts at IOL repositioning, the rotational instability persisted, necessitating the replacement of the original Sulcoflex IOL with a toric, implantable Collamer lens. Following the implantation of the toric ICL, the patient achieved excellent UDVA with no adverse events over a 4-year follow-up period. This case highlights the potential rotational instability associated with toric piggyback IOLs in keratoconic, post-PK, pseudophakic eyes and the special considerations on choosing the type of piggyback lens in these eyes.

UNASSIGNED: To rigorously derive easy to use formulae for the inclination angle for single cut rotation osteotomy that can be used for tibia deformity correction.
UNASSIGNED: Three theorems were proven using trigonometric identities and concepts of linear algebra. These were rigorously shown. The three concepts were how to convert deformities in an AP/Lateral plane to an oblique plane deformity with a true angular magnitude of deformity; how to project an angular quantity from one plane to another; and the calculation of the inclination angle for the oblique osteotomy plane. All figures in this article were created by the authors of this paper.
UNASSIGNED: From the formula derived, a statistical t-test was performed that showed no significant difference between the formula derived in this paper and the original Sangeorzan paper charts (p=0.8782).
UNASSIGNED: The formulae described in this article are a method to accurately calculate the inclination angle of the osteotomy for a single cut rotational osteotomy for tibial deformity correction.
UNASSIGNED: The article gives a deeper understanding of fundamental concepts behind deformity correction and provides an easy-to-use mathematical formula to calculate the osteotomy inclination for single cut rotational osteotomies.

Transmission electron microscopy (TEM) is an imaging technique used to visualize and analyze nano-sized structures and objects such as virus particles. Light microscopy can be used to diagnose diseases or characterize e.g. blood cells. Since samples under microscopes exhibit certain symmetries, such as global rotation invariance, equivariant neural networks are presumed to be useful. In this study, a baseline convolutional neural network is constructed in the form of the commonly used VGG16 classifier. Thereafter, it is modified to be equivariant to the p4 symmetry group of rotations of multiples of 90° using group convolutions. This yields a number of benefits on a TEM virus dataset, including higher top validation set accuracy by on average 7.6% and faster convergence during training by on average 23.1% of that of the baseline. Similarly, when training and testing on images of blood cells, the convergence time for the equivariant neural network is 7.9% of that of the baseline. From this it is concluded that augmentation strategies for rotation can be skipped. Furthermore, when modelling the accuracy versus amount of TEM virus training data with a power law, the equivariant network has a slope of - 0.43 compared to - 0.26 of the baseline. Thus the equivariant network learns faster than the baseline when more training data is added. This study extends previous research on equivariant neural networks applied to images which exhibit symmetries to isometric transformations.

The purpose of the current study is to establish a novel mathematical model in the p-waves in a photothermal semiconducting medium with an internal heat source. The fundamental equations in the context of isotropic and homogeneous medium have been presented. For the solution of the required problem, the normal mode analysis along with the displacement components, stress components and temperature has been utilized. For graphical representation of different physical quantities such as displacement components, stress components and carrier density as well as the temperature distribution. Using MATLAB R2023a software, a parametric analysis is performed, and the resulting data is represented graphically. A comparison is made to show the effect of the new parameters on the phenomenon. A graphic representation of the relationship between rotation, magnetic field, and initial stress in relation to the fluctuations in non-dimensional field quantities is provided, along with an analysis of the findings.

UNASSIGNED: To compare the effectiveness of long and short proximal femoral nail anti-rotation (PFNA) in the treatment of type A2.3 intertrochanteric fracture of femur (IFF).
UNASSIGNED: The clinical data of 54 patients with type A2.3 IFF admitted between January 2020 and December 2022 were retrospectively analyzed. According to the length of PFNA nail used in the operation, they were divided into long nail group (PFNA nail length>240 mm, 24 cases) and short nail group (PFNA nail length≤240 mm, 30 cases). There was no significant difference in baseline data such as gender, age, fracture side, body mass index, and time from fracture to operation between the two groups ( P>0.05). The operation time, intraoperative blood loss, intraoperative fluoroscopy frequency, intraoperative reduction quality score, fracture healing, and complications of the two groups were recorded and compared. Harris score was used to evaluate the hip function of patients at 1 year after operation. According to the relationship between the fracture line of type A2.3 IFF and the lesser trochanter, the two groups of patients were divided into type Ⅰ(the fracture line extends to the level of the lesser trochanter), type Ⅱ(the fracture line extends to less than 2 cm below the lesser trochanter), and type Ⅲ (the fracture line extends to more than 2 cm below the lesser trochanter), and the postoperative stability and internal fixator loosening of each subtype were evaluated.
UNASSIGNED: The operation time, intraoperative blood loss, and intraoperative fluoroscopy frequency in short nail group were significantly less than those in long nail group ( P<0.05). There was no significant difference in the intraoperative reduction quality score between the two groups ( P>0.05). Patients in both groups were followed up 12-18 months, with an average of 13.5 months. The postoperative stability score of short nail group was significantly lower than that of long nail group ( P<0.05). The Harris score in the long nail group was significantly higher than that in the short nail group at 1 year after operation ( P<0.05), but there was no significant difference in Harris score grading between the two groups ( P>0.05). Complications occurred in 3 cases of the long nail group (including 1 case of coxa varus caused by external nail entry point and 2 cases of loose internal fixator), and 7 cases of the short nail group (including 1 case of coxa varus caused by external nail entry point and 6 cases of loose internal fixator). Neither group had any anterior femoral arch damage, there was no significant difference in the incidence of complications between the two groups ( P>0.05). The number of type Ⅲ patients was relatively small and not included in the statistics; there was no significant difference in the postoperative stability score and the incidence of internal fixator loosening between the long and short nail groups in type Ⅰ patients ( P>0.05). In type Ⅱ patients, the postoperative stability score and the incidence of internal fixation loosening in the long nail group were significantly better than those in the short nail group ( P<0.05).
UNASSIGNED: Long PFNA fixation for type A2.3 IFF has longer operation time and more intraoperative blood loss, but the overall stability of fracture is better after operation. For type A2.3 IFF with fracture line extending to less than 2 cm below the lesser trochanter, long PFNA is used for fixation, although the surgical trauma is large, but the postoperative stability is better than that of short PFNA; for type A2.3 IFF with fracture line extending to the lesser trochanter, there is no significant difference in postoperative stability between long and short PFNAs.
UNASSIGNED: 比较长、短股骨近端防旋髓内钉（proximal femoral nail anti-rotation，PFNA）治疗A2.3型股骨转子间骨折（intertrochanteric fracture of femur，IFF）的临床疗效。.
UNASSIGNED: 回顾分析2020年1月—2022年12月收治且符合选择标准的54例A2.3型IFF患者临床资料，根据术中使用的PFNA主钉长度分为长钉组（PFNA主钉长度>240 mm，24例）和短钉组（PFNA主钉长度≤240 mm，30例）。两组患者性别、年龄、骨折侧别、身体质量指数、骨折至手术时间等基线资料比较差异均无统计学意义（ P>0.05）。记录并比较两组患者手术时间、术中失血量、术中透视次数、术中复位质量评分、骨折愈合情况及并发症发生情况；术后1年采用Harris评分评价患者髋关节功能。根据A2.3型IFF骨折线与小转子的关系，将两组患者细分为Ⅰ型（骨折线延伸至小转子水平）、Ⅱ型（骨折线延伸至小转子下方2 cm以内）、Ⅲ型（骨折线延伸至小转子下方2 cm以外），评价各亚型患者术后稳定性及内固定物松动情况。.
UNASSIGNED: 短钉组手术时间、术中失血量、术中透视次数均少于长钉组（ P<0.05）；两组术中复位质量评分比较差异无统计学意义（ P>0.05）。两组患者均获随访，随访时间12～18个月，平均13.5个月。短钉组术后稳定性评分低于长钉组（ P<0.05）。术后1年长钉组Harris评分优于短钉组（ P<0.05），但两组Harris评分等级比较差异无统计学意义（ P>0.05）。长钉组有3例发生并发症（包括1例入钉点偏外导致髋内翻，2例复位丢失均发生内固定物松动），短钉组有7例发生并发症（包括1例入钉点偏外导致髋内翻，6例复位丢失均发生内固定物松动），两组均无股骨前弓破损发生；两组并发症发生率比较差异无统计学意义（ P>0.05）。Ⅲ型患者因例数较少未纳入统计；Ⅰ型患者中长、短钉组术后稳定性评分及内固定物松动发生率比较差异无统计学意义（ P>0.05）；Ⅱ型患者中长钉组术后稳定性评分及内固定物松动发生率均明显优于短钉组（ P<0.05）。.
UNASSIGNED: 长PFNA固定A2.3型IFF手术时间长、术中失血量多，但患者术后总体稳定性更好。对于骨折线延伸至小转子以下2 cm以内的A2.3型IFF使用长PFNA固定，虽然手术创伤大，但患者术后稳定性较短PFNA好；对于骨折线延伸至小转子水平的A2.3型IFF使用长、短PFNA固定术后稳定性无明显差异。.

UNASSIGNED: Following total knee arthroplasty (TKA), normal knee kinematics are rarely replicated. Retention of both cruciate ligaments (bicruciate retaining TKA) has helped this. Postoperative posterior tibial slope (PPTS) may further affect ligament tension and kinematics. The objective of this study is to determine how changes between the preoperative posterior tibial slope (PTS) and PPTS affect knee kinematics.
UNASSIGNED: Twenty bicruciate retaining TKAs were performed using standard instrumentation. Fluoroscopic kinematic data were obtained during gait and a single knee bend. Differences (Δ) between radiographic measurements of preoperative and PPTS were correlated with in-vivo knee kinematics. Patients were separated into 2 groups based on their Δ values. Group I consisted of Δ values less than 0.7, indicating either a similar PPTS compared to preoperative PTS or a slightly flatter PPTS. Group II consisted of Δ values above 0.7, indicating a steepened PPTS.
UNASSIGNED: Preoperative PTS values ranged from -0.5° to 11.2°, with an average of 5.0° ± 3.4°. PPTS values ranged from 3.0° to 12.1°, with an average of 7.1° ± 3.1°. Weight-bearing range of motion (WBROM) measured from 94° to 139°, and femorotibial axial rotation ranged from -2.9° to 17.3°. A t-test revealed average values for WBROM in Group IT (Δ < 0.7) to be significantly greater than those for Group IIT (Δ > 0.7) (P = .01).
UNASSIGNED: These findings indicate that either a PPTS approximating the preoperative PTS or a slightly flattened PPTS in comparison (Δ < 0.7) is associated with WBROM greater than 130°. Values for axial rotation and anterior sliding were not significantly associated with changes to the PTS.

BACKGROUND: Physiological motion of the lumbar spine is a topic of interest for musculoskeletal health care professionals since abnormal motion is believed to be related to lumbar complaints. Many researchers have described ranges of motion for the lumbar spine, but only few have mentioned specific motion patterns of each individual segment during flexion and extension, mostly comprising the sequence of segmental initiation in sagittal rotation. However, an adequate definition of physiological motion is still lacking. For the lower cervical spine, a consistent pattern of segmental contributions in a flexion-extension movement in young healthy individuals was described, resulting in a definition of physiological motion of the cervical spine.
OBJECTIVE: This study aimed to define the lumbar spines\' physiological motion pattern by determining the sequence of segmental contribution in sagittal rotation of each vertebra during maximum flexion and extension in healthy male participants.
METHODS: Cinematographic recordings were performed twice in 11 healthy male participants, aged 18-25 years, without a history of spine problems, with a 2-week interval (time point T1 and T2). Image recognition software was used to identify specific patterns in the sequence of segmental contributions per individual by plotting segmental rotation of each individual segment against the cumulative rotation of segments L1 to S1. Intraindividual variability was determined by testing T1 against T2. Intraclass correlation coefficients were tested by reevaluation of 30 intervertebral sequences by a second researcher.
RESULTS: No consistent pattern was found when studying the graphs of the cinematographic recordings during flexion. A much more consistent pattern was found during extension, especially in the last phase. It consisted of a peak in rotation in L3L4, followed by a peak in L2L3, and finally, in L1L2. This pattern was present in 71% (15/21) of all recordings; 64% (7/11) of the participants had a consistent pattern at both time points. Sequence of segmental contribution was less consistent in the lumbar spine than the cervical spine, possibly caused by differences in facet orientation, intervertebral discs, overprojection of the pelvis, and muscle recruitment.
CONCLUSIONS: In 64% (7/11) of the recordings, a consistent motion pattern was found in the upper lumbar spine during the last phase of extension in asymptomatic young male participants. Physiological motion of the lumbar spine is a broad concept, influenced by multiple factors, which cannot be captured in a firm definition yet.
BACKGROUND: ClinicalTrials.gov NCT03737227; https://clinicaltrials.gov/ct2/show/NCT03737227.
UNASSIGNED: RR2-10.2196/14741.

Balance impairments are common in cerebral palsy. When balance is perturbed by backward support surface translations, children with cerebral palsy have increased co-activation of the plantar flexors and tibialis anterior muscle as compared to typically developing children. However, it is unclear whether increased muscle co-activation is a compensation strategy to improve balance control or is a consequence of reduced reciprocal inhibition. During translational perturbations, increased joint stiffness due to co-activation might aid balance control by resisting movement of the body with respect to the feet. In contrast, during rotational perturbations, increased joint stiffness will hinder balance control as it couples body to platform rotation. Therefore, we expect increased muscle co-activation in response to rotational perturbations if co-activation is caused by reduced reciprocal inhibition but not if it is merely a compensation strategy. We perturbed standing balance by combined backward translational and toe-up rotational perturbations in 20 children with cerebral palsy and 20 typically developing children. Perturbations induced forward followed by backward movement of the center of mass. We evaluated reactive muscle activity and the relation between center of mass movement and reactive muscle activity using a linear feedback model based on center of mass kinematics. In typically developing children, perturbations induced plantar flexor balance correcting muscle activity followed by tibialis anterior balance correcting muscle activity, which was driven by center of mass movement. In children with cerebral palsy, the switch from plantar flexor to tibialis anterior activity was less pronounced than in typically developing children due to increased muscle co-activation of the plantar flexors and tibialis anterior throughout the response. Our results thus suggest that a reduction in reciprocal inhibition causes muscle co-activation in reactive standing balance in children with cerebral palsy.