Average Rotation Research Articles

Shoulder Function Reconstruction in Brachial Plexus Birth Injury: Anterior Shoulder Release and Spinal Accessory to Suprascapular Nerve Transfer.

This study evaluated the efficacy of the spinal accessory to suprascapular nerve transfer accompanied by anterior shoulder release in restoring shoulder external rotation and abduction in patients with brachial plexus birth injury. A cohort of 41 children with brachial plexus birth injury and shoulder internal rotation contractures underwent surgical intervention. The procedure involved an anterior shoulder release encompassing subscapularis tenotomy, capsulotomy and division of the coracohumeral ligament, and transfer of the spinal accessory nerve to the suprascapular nerve. At an average of 31 months after surgery, we conducted postoperative evaluations of shoulder abduction and external rotation range of motion and compared those with the preoperative status of the patients. From the initial cohort, 26 patients with sufficient follow-up were included in the analysis. The average age at surgery was 15 months. Before surgery, patients demonstrated an average active abduction of 36° and an internal rotation contracture of 64°, measured with the elbow flexed, the shoulder adducted, and using the thorax as the 0° reference point. After surgery, there were significant improvements, with average external rotation increasing to 116° and abduction to 94°. One patient failed to recover external rotation, but most patients showed improved function without the recurrence of internal rotation contractures. Spinal accessory to suprascapular nerve transfer before or after 6 months of age combined with subscapularis tenotomy significantly improves shoulder external rotation and abduction in children with brachial plexus birth injury and internal rotation contractures. Therapeutic IV.

The association among fetal head position, fetal head rotation and descent during the progress of labor: a clinical study of an ultrasound-based longitudinal cohort study in nulliparous women.

To elucidate the effects of the timing of fetal head rotation on the labor progress and outcomes. A paired ultrasound measurement was performed at each of the three stages of labor: latency stage, active stage, and full-cervical-dilatation stage. The measurements included fetal head position, head-perineum distance (HPD) and the angle of progression (AOP). A total of 46 pregnancy women were included and a total of 102 effective measurements were collected. The cases in occipital anterior position were all eutocia. The rate of cesarean section in the left transverse occipital group was the highest (15.7 %, 3/19). There were 13 cases (37.1 %) with fetal head rotation occur during active phase, changing from occipital transverse to anterior. Ten cases (28.6 %) rotated in the second stage of labor. The average rotation degree of occipital transverse to anterior position was 62.6°. When AoP <95°, 100 % of the women were occipital transverse; When AoP≥125°, 66.7 % was occipital anterior. The rate of oxytocin utilization and epidural analgesia in the occipital posterior group was higher than that in the other groups (71.4 and 85.7 %, respectively). Occipital transverse is the most common fetal head position in the early stage of labor and fetal head rotation occurs mostly in the active phase and the second stage of labor. Sufficient time should be given in labor management for women that who tried vaginal delivery without contraindications.

Continuously tunable negative pressure for engineering high-symmetry nanocrystalline phases

In this work, the phenomenon of strain induced by a mismatch in thermal expansion coefficients between a thin film and its substrate is harnessed in a new context, replacing the canonical planar support with a three-dimensional (3-D), nanoconfining scaffold in which we embed a material of interest. In this manner, we demonstrate a general approach to exert a continuously tunable, triaxial, tensile strain, defying the Poisson ratio of the embedded material and achieving the exotic condition of "negative pressure." This approach is hypothetically generalizable to materials of low modulus and high thermal expansion coefficient, and we use it here to achieve negative pressure in perovskite-phase CsPbI3 embedded within the cylindrical pores of anodic aluminum oxide membranes. Through controlled thermal hysteresis, the perovskite crystal structure can be continuously tuned toward higher symmetry when confined in a scaffold with pore size <40 nm, in contrast with the symmetry-reducing action of any other mechanical perturbation. We use this effect to control the octahedral rotation angle that is critical to the remarkable photovoltaic attributes of halide perovskites. Under hundreds of megapascals of apparent negative pressure, the bandgap tunability is observed to follow the same quantitative trend observed for hydrostatic positive pressure, exploring the negative pressure region and demonstrating the relative dominance of bond stretching effects over average octahedral rotation angle on electronic structure. This study reveals and quantifies the structural and electronic consequences of 3D tensile strain present by design and provides a framework for understanding adventitious strain present in all nanocomposite materials.

System Tautochronic Path for Pendulum Vibration Absorber Based on Simple Harmonic Oscillator Transformation

Abstract Centrifugal pendulum vibration absorbers (CPVAs) are essentially collections of pendulums attached to a rotating component or components within a mechanical system for the purpose of mitigating the typical torsional surging that is inherent to internal combustion engines and electric motors. The dynamic stability and performance of CPVAs are highly dependent on the motion path defined for their pendulous masses. Assemblies of absorbers are tuned by adjusting these paths such that the pendulums respond to problematic orders (multiples of average rotation speed) in a way that smooths the rotational accelerations arising from combustion or other nonuniform rotational acceleration events. For most motion paths, pendulum tuning indeed shifts as a function of the pendulum response amplitude. For a given motion path, the tuning shift that occurs as pendulum amplitude varies produces potentially undesirable dynamic instabilities. Large amplitude pendulum motion that mitigates a high percentage of torsional oscillation while avoiding instabilities brought on by tuning shift introduces complexity and hazards into CPVA design processes. Therefore, identifying pendulum paths whose tuning order does not shift as the pendulum amplitude varies, so-called tautochronic paths, may greatly simplify engineering design processes for generating high-performing CPVAs. To illustrate this new approach and results, a tautochronic cutout shape producing constant period system motion is obtained for a simplified problem involving a mass sliding in the cutout of a larger mass that is free to translate horizontally without friction in a constant gravitational field, where the translating base mass replaces the rotating rotor in the centrifugal field.

A Base-Map-Guided Global Localization Solution for Heterogeneous Robots Using a Co-View Context Descriptor

With the continuous advancement of autonomous driving technology, an increasing number of high-definition (HD) maps have been generated and stored in geospatial databases. These HD maps can provide strong localization support for mobile robots equipped with light detection and ranging (LiDAR) sensors. However, the global localization of heterogeneous robots under complex environments remains challenging. Most of the existing point cloud global localization methods perform poorly due to the different perspective views of heterogeneous robots. Leveraging existing HD maps, this paper proposes a base-map-guided heterogeneous robots localization solution. A novel co-view context descriptor with rotational invariance is developed to represent the characteristics of heterogeneous point clouds in a unified manner. The pre-set base map is divided into virtual scans, each of which generates a candidate co-view context descriptor. These descriptors are assigned to robots before operations. By matching the query co-view context descriptors of a working robot with the assigned candidate descriptors, the coarse localization is achieved. Finally, the refined localization is done through point cloud registration. The proposed solution can be applied to both single-robot and multi-robot global localization scenarios, especially when communication is impaired. The heterogeneous datasets used for the experiments cover both indoor and outdoor scenarios, utilizing various scanning modes. The average rotation and translation errors are within 1° and 0.30 m, indicating the proposed solution can provide reliable localization support despite communication failures, even across heterogeneous robots.

Exploring noisy Jeffery orbits: A combined Fokker-Planck and Langevin analysis in two and three dimensions.

The behavior of nonspherical particles in a shear flow is of significant practical and theoretical interest. These systems have been the object of numerous investigations since the pioneering work of Jeffery a century ago. His eponymous orbits describe the deterministic motion of an isolated, rodlike particle in a shear flow. Subsequently, the effect of adding noise was investigated. The theory has been applied to colloidal particles, macromolecules, anisometric granular particles, and most recently to microswimmers, for example, bacteria. We study the Jeffery orbits of elongated (uniaxial, prolate) particles subject to noise using Langevin simulations and a Fokker-Planck equation. We extend the analytical solution for infinitely thin needles (β=1) obtained by Doi and Edwards to particles with arbitrary shape factor(0≤β≤1) and validate the theory by comparing it with simulations. We examine the rotation of the particle around the vorticity axis and study the orientational order matrix. We use the latter to obtain scalar order parameters s and r describing nematic ordering and biaxiality from the orientational distribution function. The value of s (nematic ordering) increases monotonically with increasing Péclet number, while r (measure of biaxiality) displays a maximum value. From perturbation theory, we obtain simple expressions that provide accurate descriptions at low noise (or large Péclet numbers). We also examine the orientational distribution in the v-grad v plane and in the perpendicular direction. Finally, we present the solution of the Fokker-Planck equation for a strictly two-dimensional (2D) system. For the same noise amplitude, the average rotation speed of the particle in 3D is larger than in 2D.

Influence of the surrounding environment on the response of seated midsize male volunteers subjected to lateral sled accelerations

Predicting vehicle occupants’ posture during evasive manoeuvres is crucial for assessing their safety in the event of a collision. Volunteer experiments have been performed in the past under lateral accelerations, both within a vehicle cabin and on a seat mounted on a sled. However, discrepancies in the volunteer responses between both setups have been identified. This study hypothesizes that the response of the volunteers differs as a consequence of the proximity to the frame in the vehicle cabin, in comparison to the absence of such a structure on the sled.The present study conducted a novel sled experiment, on which five volunteers with anthropometry comparable to the 50th percentile male were subjected to 0.3 g lateral accelerations, with three different surrounding environments. In twelve pulses, an additional lateral structure was placed to the right or left side of the seated volunteers. The volunteers were asked to either brace or relax their muscles.The results show significant differences between the configurations with and without the structure placed on the right side. This effect was observed for both the lateral excursion of the upper body and the corresponding rotation when the volunteers were relaxed (p < 0.01). The average maximum lateral head rotation decreased from 27° to 14° with the structure on the right. No significant difference in head rotation was found for the braced muscle configuration.This study supports the hypothesis that the proximity to a surrounding environment influences human responses during dynamic loading. Nevertheless, there was no significant difference in maximum muscle activation between the configurations, but a faster reaction of the sternocleidomastoid muscle with the presence of the structure.

An Extremely Active Repeating Fast Radio Burst Source in a Likely Nonmagneto-ionic Environment

Fast radio bursts (FRBs) are bright radio bursts originating at cosmological distances. Only three repeating FRBs FRB 20121102A, FRB 20190520B, and FRB 20201124A among ∼60 known repeating FRBs have circular polarization. We observed the FRB 20220912A with the Robert C. Byrd Green Bank Telescope (GBT) at L-band on 2022 October 24 and detected 128 bursts in 1.4 hr, corresponding to a burst rate of about 90 hr−1, which is the highest yet for FRBs observed by the GBT. The average rotation measure (RM) was −0.4 ± 0.3 rad m−2 with negligible intraday RM change, indicating a likely nonmagneto-ionic environment. A total of 61% of bursts have a linear polarization fraction greater than 90%. Approximately 56% of the bright bursts have circular polarization. A downward drift in frequency and polarization angle swings were found in our sample. The characterization of FRB 20220912A indicates that the circular polarization is unlikely to be caused by the magneto-ionic environment for at least some of the repeating FRB population.

Investigation on in-situ tensile behaviors of 6061 aluminum alloy fabricated by wire additive friction stir deposition

Rod based additive friction stir deposition (R-AFSD) offers unique advantages for the integrated manufacturing of aluminum alloy near-net-shape large parts. However, the deposition process often faces issues like thick ends of raw material rods and difficulties in continuous feeding. In this study, wire based additive friction stir deposition (W-AFSD) was used for the solid state deposition of 3 mm diameter 6061 aluminum alloy wire. The microstructure evolution and mechanical properties of the deposit along the build direction were systematically characterized, clarifying the recrystallization mechanism and isotropy of the mechanical properties. In-situ scanning electron microscopy (SEM) and electron backscattered diffraction (EBSD) were used to study the deformation behavior of the deposit during in situ tensile testing, revealing a cooperative deformation mechanism involving grain rotation and intragranular slip. Results show that during in-situ tensile testing, the average rotation angle of five selected grains is 6.90°. Additionally, deposits with numerous grain boundaries due to recrystallization can hinder dislocation movement and pin the slip system within the grains during tensile testing. Due to the synergy of these mechanisms, the yield strengths of the longitudinal and transverse samples of the deposit are 183 MPa and 190 MPa, respectively, much higher than previously reported values. This article introduces a new solid state additive manufacturing method, offering new insights for efficient, high-strength continuous additive manufacturing of aluminum alloys and their deformation mechanisms.

A LiDAR-Camera Joint Calibration Algorithm Based on Deep Learning.

Multisensor (MS) data fusion is important for improving the stability of vehicle environmental perception systems. MS joint calibration is a prerequisite for the fusion of multimodality sensors. Traditional calibration methods based on calibration boards require the manual extraction of many features and manual registration, resulting in a cumbersome calibration process and significant errors. A joint calibration algorithm for a Light Laser Detection and Ranging (LiDAR) and camera is proposed based on deep learning without the need for other special calibration objects. A network model constructed based on deep learning can automatically capture object features in the environment and complete the calibration by matching and calculating object features. A mathematical model was constructed for joint LiDAR-camera calibration, and the process of sensor joint calibration was analyzed in detail. By constructing a deep-learning-based network model to determine the parameters of the rotation matrix and translation matrix, the relative spatial positions of the two sensors were determined to complete the joint calibration. The network model consists of three parts: a feature extraction module, a feature-matching module, and a feature aggregation module. The feature extraction module extracts the image features of color and depth images, the feature-matching module calculates the correlation between the two, and the feature aggregation module determines the calibration matrix parameters. The proposed algorithm was validated and tested on the KITTI-odometry dataset and compared with other advanced algorithms. The experimental results show that the average translation error of the calibration algorithm is 0.26 cm, and the average rotation error is 0.02°. The calibration error is lower than those of other advanced algorithms.

Clinical Effect Analysis of Posterior Chamber Intraocular Lens Implantation for Correcting High Myopia and Astigmatism

Objective: To explore the corrective effect of posterior chamber intraocular lens implantation with phakic eyes in the treatment of high myopia and astigmatism. Methods: From May 2023, the hospital began to collect the case data of diagnosis and treatment of high myopia and astigmatism. By May 2024, 310 cases were included, all of which were treated with posterior chamber intraocular lens implantation. The visual acuity, astigmatism and axial position of the intraocular lens were observed before and after treatment. Results: At different time points after the operation, the patient’s vision was significantly improved compared with that before the operation (P &lt; 0.05), and the vision level was equal to or greater than the best-corrected vision before the operation. At different time points after the operation, the average rotation of the intraocular lens was less than 5 degrees. Astigmatism was significantly lower than that before the operation (P &lt; 0.05). After the operation, the intraocular pressure increased in 11 cases, accounting for 3.55%, with no adverse complications such as lens turbidity, glare and obvious halo occurring. Conclusion: The posterior chamber intraocular lens implantation with phakic eyes has an ideal correction effect in the treatment of high myopia and astigmatism, which can effectively improve the vision level of patients and reduce the degree of astigmatism, and has high effectiveness and safety.

Camera LiDAR calibration: an automatic and accurate method with novel PLE metrics

Abstract Camera-LiDAR calibration is a crucial aspect of perception systems and sensor fusion in various fields, facilitating the fusion of data from cameras and LiDAR sensors for applications such as autonomous vehicles, robotics, and augmented reality. In this paper, we presented a novel multi-modal fusion method that introduces an efficient camera-LiDAR joint calibration technique using a simple checkerboard. Our method estimates the 3D rigid transformation of the camera system with respect to the LiDAR frame by establishing 2D-to-3D point correspondences for geometric calibration. We improved the idea of the traditional PNP (Perspective-N-Point) algorithm by employing point cloud segmentation and clustering to re-match the checkerboard. When compared with the calibration methods in the Autoware and MATLAB calibration toolbox, the reprojection error was improved by 38.13\% and 58.30\% respectively. The average translation error was improved by 78.26\% and 51.61\% respectively, while the average rotation error is improved by 75\% and 60.78\% respectively, which has a great improvement in all three areas. At the same time, we propose a new evaluation metric for joint calibration results based on reprojected images: PLE (Pixel-Level Evaluation) index to reflect the accuracy of the joint calibration of the camera and LiDAR. An automatic calibration software has been developed for the calibration of the camera's intrinsic parameters as well as for the joint calibration of the camera-LIDAR extrinsic parameters. We have extensively validated our algorithm using the Intel RealSense Depth D435 Camera and LeiShen C16-151B LiDAR.

A bronchoscopic navigation method based on neural radiation fields.

We introduce a novel approach for bronchoscopic navigation that leverages neural radiance fields (NeRF) to passively locate the endoscope solely from bronchoscopic images. This approach aims to overcome the limitations and challenges of current bronchoscopic navigation tools that rely on external infrastructures or require active adjustment of the bronchoscope. To address the challenges, we leverage NeRF for bronchoscopic navigation, enabling passive endoscope localization from bronchoscopic images. We develop a two-stage pipeline: offline training using preoperative data and online passive pose estimation during surgery. To enhance performance, we employ Anderson acceleration and incorporate semantic appearance transfer to deal with the sim-to-real gap between training and inference stages. We assessed the viability of our approach by conducting tests on virtual bronchscopic images and a physical phantom against the SLAM-based methods. The average rotation error in our virtual dataset is about 3.18 and the translation error is around 4.95 mm. On the physical phantom test, the average rotation and translation error are approximately 5.14 and 13.12 mm. Our NeRF-based bronchoscopic navigation method eliminates reliance on external infrastructures and active adjustments, offering promising advancements in bronchoscopic navigation. Experimental validation on simulation and real-world phantom models demonstrates its efficacy in addressing challenges like low texture and challenging lighting conditions.

Experimental studies on lateral bearing capacity of modified tripod suction caissons for offshore wind turbines in silty clay

In recent years regular tripod suction caissons are commonly used in offshore wind farm projects because of economic feasibility and environment-friendly work principles. The design of a modified tripod suction caisson composed of three caissons with different diameters can improve the capacity behaviour in the direction of strong wind within a considered construction cost. This paper carried out model tests to study the lateral bearing capacity of modified tripod suction caissons in silty clay. Based on the equilibrium equation of vertical force of modified tripod suction caissons the average vertical subgrade reaction modulus is proposed to investigate the relationship between it and rotation, which is of paramount importance to the nonlinear lateral bearing capacity. The results show that the range of bearing capacity factors increases with the increasing effective diameter-height ratio indicating that modified tripod suction caisson with reasonable combinations can effectively improve its bearing capacity in a certain loading direction. The sum of the bearing capacity factors of three monopod suction caissons falls in the range of the capacity factors of the tripod foundation consisting of the above caissons. Suction under the lid increases with the increasing lateral load and seems to be not related to the combinations of suction caissons with different diameters. By fitting the experimental data, it is found that there is a power exponential relationship between the average vertical subgrade reaction modulus and rotation of the foundation.

Design and Experiment of In-Situ Bionic Harvesting Device for Edible Sunflower

In view of the low degree of mechanization and poor quality of harvesting of edible sunflower after drying, an in situ bionic harvesting device was designed, which can achieve low-loss harvesting of edible sunflower without removing the edible sunflower disc. According to the physical characteristics of sunflower stalks in the field, influencing factors of in situ low-loss feeding were obtained, and the structural parameters of the in situ feeding mechanism were determined. Based on bionic technology and static analysis, the influencing factors on the performance of the bionic threshing mechanism were obtained. By analyzing the mechanical characteristics of edible sunflower seed, the operation parameters of the seed collection mechanism were determined. Based on the structural analysis results of the harvesting device, a response surface optimization test was carried out. The test results show that when the average rotation speed of the bionic loosening roller was 113.57 rpm, the average rotation speed of the simulated artificial striking roller was 230.80 rpm, the average forward speed of the harvesting device was 0.58 m/s, the working quality of the harvesting device was the best, the seed loss rate was 2.12%, and the edible sunflower disc threshing rate was 98.96%. A field verification test further confirms that under the optimal working parameters, the relative deviation between test indexes and response surface optimization test results was less than 2%. During the operation process, the movement of key components of the harvesting device was coordinated and stable. The research results can provide new ideas for the mechanized harvesting of the edible sunflower disc after drying.

Contributions of capsular releases to femoral exposure in total hip arthroplasty via the direct anterior approach

BackgroundIn total hip arthroplasty via the direct anterior approach, appropriate exposure is critical to allow preparation of the femur. The objective of this study was to explore the optimal soft tissue releases needed to allow broaching of the femur through a combination of experimental tests and computer simulations. MethodsFourteen full-body cadaveric specimens were included in this study. Total hip arthroplasty was performed via the direct anterior approach with the femur at 20° adduction and 20°extension. Soft tissue releases were performed sequentially, namely, the transverse iliofemoral ligament, descending iliofemoral ligament, ischio-femoral ligament, conjoint tendon, and obturator externus. After each release, the femur mobility was assessed by applying a 6 Nm external rotation torque and a 120 N distraction force. Subsequently, using specimen-specific models and models of the broach and handle, the broach passage after each release was simulated, and the release that allowed broach passage was analyzed. FindingsThe average external rotation after releasing the transverse and descending iliofemoral ligaments increased by 14.1° ± 6.1° and 13.8° ± 5.3°. With subsequent soft tissue releases, the rotational mobility increased incrementally, though the impact decreased. Impingement between the broach passage and the pelvis was mainly at the anterior superior iliac spine and the anterior inferior iliac spine. The volume of impingement decreased from 4.8 ± 4.5 cm3 after resection of the femoral head to 1.8 ± 1.6 cm3 and 1.2 ± 1.9 cm3 after release of the transverse and descending iliofemoral ligament, respectively. InterpretationWith sequential soft-tissue releases, the femur mobility increased incrementally. However, the number of releases needed for each femur varied extensively between specimens. Most (10/14) femurs became accessible after the release of the ilio-femoral or ischio-femoral ligament.

Tuberosity healing in reverse shoulder arthroplasty for proximal humerus fractures with a diaphyseal press-fit humeral stem

BackgroundReverse shoulder arthroplasty (RSA) is a viable option for proximal humerus fractures (PHFs) in the elderly, and cemented humeral fixation is the standard of care. This study evaluates the influence of a diaphyseal press-fit stem with a 142° humeral inclination on tuberosity healing (TH) and functional outcome in RSA for PHF. MethodsTwenty-three patients received an RSA for PHF by a single surgeon at one center over a 2-year period. The humeral stem design was intended for diaphyseal press fit with a 142° humeral inclination. The tuberosities were repaired for each patient with bone graft and a standard suture technique. Patients’ clinical and radiographic outcomes were collected with a minimum 12-month follow-up. ResultsNineteen of 23 patients (83%), with a mean age of 75 + years, were available for follow-up at an average of 14 months. Radiographic analysis showed 68% of patients had evidence of TH. Grade 1 scapular notching was found in 32% of patients. There was no implant loosening or subsidence noted. Average range of motion was 163° ± 15° degrees of forward flexion, 113° ± 24° of abduction, internal rotation to the waist, and an average external rotation of 7 ± 1.5 as measured by the Constant-Murley score. The average American Shoulder and Elbow Surgeons score was 81.8, and the average Constant-Murley score was 67.9. While not significant, those with TH trended toward better clinical outcomes. There was a 0% revision rate. ConclusionA press-fit stem designed for diaphyseal fixation provides consistent reliable results in RSA for PHF. A high percentage of TH was appreciated with a 142° humeral inclination, neutral glenosphere construct, and a standardized bone grafting, suture technique. TH is associated with improved patient outcomes.

The Application Characteristics and Creation of Digital Sculpture Based on Parameter Model

Recently, digital sculpture based on parametric models has emerged both domestically and internationally. To improve the accuracy and efficiency of constructing digital sculpture parameter models, this study proposes a method for constructing digital sculpture parameter models based on improved point cloud registration algorithms by iterating the nearest point algorithm and multi-scale matrix descriptors to increase the iteration efficiency and accuracy of point cloud registration algorithms. The results show that under the Bunny model, the number of three scale feature points is 2146, and the coarse registration error is 0.925 * 10-6 m; As the noise increases, the efficiency of the algorithm proposed in the study increases by an average of 10.1%. The average relative rotation error is reduced by 1-2 orders of magnitude, and the registration time is shortened by 62.7% on average. For a 30dB noise point cloud, it is reduced by one order of magnitude, and as the noise increases, the efficiency of the algorithm proposed in the study increases by an average of 10.1%. In the Dragon model, the number of three scale feature points is 2235, the coarse registration time is only 26 seconds, and the registration error is 0.285 * 10-5m; The average relative rotation error is reduced by 1-2 orders of magnitude, and the registration time is shortened by 62.7% on average. The digital sculpture creation method on the ground of parameter models proposed in this study has improved the registration accuracy and efficiency of parameter models.

Assessment of average femoral component rotation for balancing functionally aligned total knee replacement in varus deformity: Robotic image guidance study

Introduction and purposeEnsuring proper femoral component alignment post-Total Knee Arthroplasty (TKA) is crucial for normal patellofemoral (PF) kinematics. However, the customary 3° external rotation relative to the Posterior Condylar Axis (PC Axis) may not universally apply, and the expected final femoral component rotation remains unclear in functionally aligned knees. This study examines the relation between the Transepicondylar Axis (TEA) and PC axis, known as Posterior Condylar Angle (PCA) in Indian patients along with factors influencing PCA, and the feasibility of reproducing patient-specific PCA using image-guided Cuvis joint robot. MethodsForty patients (52 Knees) with primary osteoarthritis and varus deformity were prospectively evaluated. Native PCA was determined using CT-based J planner. Pre-operative patellar shape, PF tilt, PF shift, final femoral component rotation (representing post-operative PCA), final patellar tracking, and post-operative functional and radiological assessment at 3 months were recorded. ResultsStudy participants averaged 64.3 years of age, with a female-to-male ratio of 23 to 17. Varus deformities varied, with IA2 being most prevalent, and sagittal plane deformities included fixed flexion (34.6 %) and hyperextension (44.2 %). The average PCA was 1.9° (range: 0°–7.3°), with most knees (41 out of 52) below 3°. The majority had Wiberg type 1 patellae, with pre-operative patellar tilt averaging 5.63°, reducing post-operatively to 4.43°. Most patients (37 out of 40) achieved excellent Knee Society functional scores at the 3-month mark. Complications included one case of delayed wound healing and one femoral array pin breakage. Notably, our study revealed a significant deviation in PCA from the commonly reported 3° in Western literature, underscoring the need for region-specific considerations in TKA planning. ConclusionPCA of our population is statistically different from customary 3° followed with jig system. Image guided Robotics helps to identify patients specific PCA and reproducing the same was more commonly possible in patients with reducible Varus deformity.

Time Structure of the Average Rotation Measure for Accretion Disk in Shearing Box Approximation

Time Structure of the Average Rotation Measure for Accretion Disk in Shearing Box Approximation