Straight Position Research Articles

Impact of Significant Sac Shrinkage on Endograft Tortuosity at 5 Years Post-EVAR: A Retrospective Analysis

Significant sac shrinkage after endovascular aortic aneurysm repair (EVAR) is generally considered a positive outcome indicative of durable clinical success. However, its impact on endograft configuration is rarely addressed. Sac remodeling and volume loss due to shrinkage can potentially cause deformation of endograft components, resulting in limb angulation and compression. We investigated the hypothesis that significant sac shrinkage could affect endograft tortuosity at 5 years post-EVAR. We retrospectively reviewed patients who underwent elective EVAR for infrarenal abdominal aortic aneurysm between June 2007 and December 2018. Patients with early postoperative and 5-year follow-up CT images were included. Patients treated with modular bifurcated endografts (Zenith, Endurant, Excluder, and Incraft) were analyzed. The "shrinkage" group comprised patients with >10mm diameter reduction, while the "stable" group had ±5mm diameter change at 5 years. Tortuosity index (TI) was calculated as the ratio of centerline distance to straight-line distance between proximal and distal endograft edges. The association between sac shrinkage and ≥5% increase of TI (≥5%ΔTI) was analyzed for both ipsilateral and contralateral sides. Of 136 patients enrolled, 80 were in the shrinkage group and 56 in the stable group. On the ipsilateral side, ≥5%ΔTI was observed in 24 cases (17.6%). Patients with ipsilateral ≥5%ΔTI had significantly shorter median neck lengths (22mm vs 30mm, p = 0.030). Sac shrinkage ≥15mm was negatively associated with ≥5%ΔTI compared to stable sac (p = 0.027). Logistic regression showed sac shrinkage ≥15mm had a significant negative correlation with ≥5%ΔTI (p = 0.025, HR [95% CI] 0.218 [0.057-0.824]). On the contralateral side, ≥5%ΔTI (19 cases, 14.0%) was associated with shorter neck length but not with sac shrinkage. In the shrinkage group, cross-leg positioning resulted in a significant increase in ipsilateral TI at 5 years compared to straight positioning (median ΔTI: 1.8% vs 0.0%, p = 0.013). No reinterventions for leg-related events were necessary during the 5-year follow-up period. Contrary to our initial hypothesis, significant sac shrinkage does not adversely affect endograft configuration and may help stabilize tortuosity on the ipsilateral side. However, in patients with crossed-leg configuration, continued vigilant observation may be warranted even after achieving sac shrinkage, as it could exacerbate tortuosity. Shorter neck length was associated with increased tortuosity on both sides. Further research is needed to confirm these findings and consider potential confounding factors, including the impact of different endograft designs.

Scaling law for a buckled elastic filament in a shear flow.

We analyze the three-dimensional (3D) buckling of an elastic filament in a shear flow of a viscous fluid at low Reynolds number and high Péclet number. We apply the Euler-Bernoulli beam (elastica) theoretical model. We show the universal character of the full 3D spectral problem for a small perturbation of a thin filament from a straight position of arbitrary orientation. We use the eigenvalues and eigenfunctions for the linearized elastica equationin the shear plane, found earlier by Liu etal. [Phys. Rev. Fluids 9, 014101 (2024)2469-990X10.1103/PhysRevFluids.9.014101] with the Chebyshev spectral collocation method, to solve the full 3D eigenproblem. We provide a simple analytic approximation of the eigenfunctions, represented as Gaussian wave packets. As the main result of the paper, we derive the square-root dependence of the eigenfunction wave number on the parameter χ[over ̃]=-ηsin2ϕsin^{2}θ, where η is the elastoviscous number and the filament orientation is determined by the zenith angle θ with respect to the vorticity direction and the azimuthal angle ϕ relative to the flow direction. We also compare the eigenfunctions with shapes of slightly buckled elastic filaments with a non-negligible thickness with the same Young's modulus, using the bead model and performing numerical simulations with the precise hydromultipole numerical codes.

Effect of Computer Tasks in Straight Gaze on Corneal Topographic Indices.

To investigate the effect of the near visual task of movie-watching in the straight gaze position on corneal topographic parameters. Thirty myopic young adults with an average age of 25.10 4.13 years were recruited for the study. The designed near visual task consisted of watching a movie in the straight gaze position at a distance of 40 cm for 30 minutes. Corneal topography was performed using Oculus Keratograph 4 (OCULUS, Wetzlar, Germany) before and immediately after watching the movie, as well as at 10, 20, and 30 minutes intervals after completing this near visual task. Zernike coefficients, asphericity indices, refractive parameters, and diagnostic indices of keratoconus were recorded for statistical analysis. Movie-watching at a close distance solely using the straight gaze position had no effect on Zernike coefficients (P 0.130). Also, watching the movie had no effect on other corneal topography parameters including irregularities (P = 0.208), spherical eccentricity (P = 0.270), maximum decentration (P = 0.553), axis of maximum decentration (P = 0.186), peripheral astigmatism (P = 0.179), and average asphericity of the quadrants at 10 to 30º (P 0.163). The results of the present study showed that watching movies in the straight gaze position had no effect on corneal topographic parameters and did not cause errors in corneal topographic measurements.

Influence of variable hinge positioning on coronal and sagittal alignment in uniplanar medial open-wedge high tibial osteotomy.

There is a high risk of increasing the posterior tibial slope (PTS) during medially opening-wedge high tibial osteotomy (mowHTO). Most recently, the idea of intentional simultaneous coronal and sagittal correction, using uniplanar cutting techniques has emerged. This study aims to examine the influences of variable hinge positioning and osteotomy gap height on the sagittal and coronal plane. Twenty uniplanar mowHTOs were performed in standardised (left) solid-foam proximal tibia models. In the different models, hinge position was rotated stepwise by 10°, between 90° (cutting straight medial to lateral) and 0° (cutting straight anterior to posterior) (n = 10). Additionally, gap heights of 5 and 10 mm were produced and analysed. Logistic regression analysis was performed to calculate a predictive regression formula for the relation between gap height, hinge rotation and the changes of medial proximal tibia angle (MPTA), medial and lateral PTS. Between cutting angles of 90 and 20°, the MPTA was mainly influenced by the gap height (0.95° MPTA per 1 mm gap height), but not by the cutting angle. Between 20 and 0°, the MPTA was decreased by 3.6° per 10° of rotation, but not by the gap height. Between cutting angles of 90 and 10°, the PTS was increased linearly by 0.97° per 10° of rotation and by 0.61° per 1 mm gap height. In mowHTO with lateral hinge positions, the MPTA is mainly influenced by gap height. Changes of PTS can be avoided by a straight lateral hinge position. In posterior hinge locations (0-20°), changes of MPTA are mainly caused by hinge rotation, but not by gap height. Level III, Case-control study.

Impact of Various Non-Contrast-Enhanced MRA Techniques on Lumen Visibility in Vascular Flow Models with a Surpass Evolve Flow Diverter.

Silent MRA has shown promising results in evaluating the stents used for intracranial aneurysm treatment. A deep learning-based denoising and deranging algorithm was recently introduced by GE HealthCare. The purpose of this study was to compare the performance of several MRA techniques regarding lumen visibility in silicone models with flow diverter stents. Two Surpass Evolve stents of different sizes were implanted in two silicone tubes. The tubes were placed in separate boxes in the straight position and in two different curve configurations and connected to a pulsatile pump to construct a flow loop. Using a 3.0T MRI scanner, TOF and silent MRA images were acquired, and deep learning reconstruction was applied to the silent MRA dataset. The intraluminal signal intensity in the stent (SIin-stent), in the tube outside the stent (SIvessel), and of the background (SIbg) were measured for each scan. The SIin-stent/SIbg and SIin-stent/SIv ratios were higher in the silent scans and DL-based reconstructions than in the TOF images. The stent tips created severe artefacts in the TOF images, which could not be observed in the silent scans. Our study demonstrates that the DL reconstruction algorithm improves the quality of the silent MRA technique in evaluating the flow diverter stent patency.

Slingshot Accuracy in Traditional Games: What is The Ideal Grip in Shooting?

The purpose of this study was to analyze the biomechanics of the ideal grip on the traditional game of slingshots. This study used quantitative methods that were described in detail using descriptive analytics with a one-shot case study design. The sample in this study consisted of 10 people who were activists of the traditional slingshot game in Semarang Regency and filled out complete consent information as a willingness to participate in the research to completion. The data in this study is in the form of kinematic data obtained from the results of video analysis using Kinovea software version 0.9.5. The quantitative data in this study is in the form of a recap of kinematic data consisting of 3 phases, namely the preparation phase; the release phase; and the follow-through phase. The results of this study found that the preparatory phase had an average grip angle of 99.08 ± 5,995 degrees. Grip angle data at release phase 99.66 ± 4.977 degrees. This study found the conclusion that the ideal grip is a straight hand position parallel to the pull of the arm until an angle of approximately 90 degrees is formed with the slingshot position slightly tilted, this position can provide enough space for the other hand to pull the slingshot rubber back. So that the pull carried out can be maximized and can be adjusted to the intended target distance. It is expected that further research can discuss the analysis of pull length and shot accuracy. Keywords: biomechanics analysis; traditional games, slingshot; grip.

The coax monopole antenna: A flexible end-fed antenna for ultrahigh field transmit/receive arrays.

The coax monopole antenna is presented for body imaging at 7 T. The antenna is fed at one end, eliminating the possibility of cable-coil coupling and simplifying cable routing. Additionally, its flexibility improves loading to the subject. Like the coax dipole antenna, an interruption in the shield of the coaxial cable allows the current to extend to the outside of the shield, generating a B1 + field. Matching is achieved using a single inductor at the distal side, and a cable trap enforces the desired antenna length. Finite difference time domain simulations are employed to optimize the design parameters. Phantom measurements are conducted to determine the antenna's B1 + efficiency and to find the S-parameters in straight and bent positions. Eight-channel simulations and measurements are performed for prostate imaging. The optimal configuration is a length of 360 mm with a gap position of 40 mm. Simulation data show higher B1 + levels for the coax monopole (20% in the prostate), albeit with a 5% lower specific absorbance rate efficiency, compared to the fractionated dipole antenna. The S11 of the coax monopole exhibits remarkable robustness to loading changes. In vivo prostate imaging demonstrates B1 + levels of 10-14 μT with an input power of 8 × 800 W, which is comparable to the fractionated dipole antenna. High-quality images and acceptable coupling levels were achieved. The coax monopole is a novel, flexible antenna for body imaging at 7 T. Its simple design incorporates a single inductor at the distal side to achieve matching, and one-sided feeding greatly simplifies cable routing.

Suprapatellar tibial fracture nailing is associated with lower rate for acute compartment syndrome and the need for fasciotomy compared with the infrapatellar approach

BackgroundIntramedullary tibial nailing (IMN) is the gold standard for stabilizing tibial shaft fractures. IMN can be performed through an infra- or suprapatellar approach.PurposeThe aim of this study is to compare the rate of fasciotomies for acute compartment syndrome between infra- and suprapatellar approaches.MethodsA total of 614 consecutive patients who were treated with IMN for tibial fracture between October 2007 and February 2020 were included in the study. The approach used for IMN was determined by the operating surgeon. Infrapatellar IMN was performed with the knee in deep flexion position, with or without calcaneal traction. Suprapatellar IMN was performed in straight or semiflexed position. The diagnosis of compartment syndrome was based on clinical analysis, but for some patients, a continuous compartment pressure measurement was used. The primary outcome was the rate of peri- and postoperative compartment syndrome treated with fasciotomies.ResultsThe study sample included 513 patients treated with infrapatellar IMN and 101 patients treated with suprapatellar IMN technique. The mean age of the patients was 44.7 years (infrapatellar technique) and 48.4 years (suprapatellar technique). High energy trauma was seen in 138 (27%) patients treated with infrapatellar technique and in 39 (39%) patients treated with suprapatellar technique. In the suprapatellar group (n = 101), there were no cases of peri- or postoperative compartment syndrome treated with fasciotomies. In the infrapatellar group (n = 513), the need for fasciotomies was stated in 67 patients, 31 patients (6.0%) perioperatively and in 36 patients (7.0%) postoperatively. The rate of fasciotomies (0/101 versus 67/513 cases) differed significantly (p < 0.001). There were no significant differences in the fracture morphology or patient demographics between the study groups.ConclusionsThe suprapatellar technique is recommended over the infrapatellar approach in the treatment of tibial shaft fractures. The rate of peri- and postoperative compartment syndrome and the need for fasciotomies was significantly lower with the suprapatellar technique. The major cause of increased rate of peri- or postoperative acute compartment syndrome with infrapatellar IMN technique is presumably associated with the positioning of the patient during the operation.Level of evidence3.

Evaluation of natural head position changes in the treatment of class II malocclusions with functional appliance

Objectives: The position of the head to the neck is affected by various factors, including respiratory tract features, temporomandibular joint disorders, type of occlusion, and physical aspects. In addition, malocclusion can negatively affect the head-neck position. The present study aimed to evaluate changes in natural head position following treatment of Class II malocclusions with Farmand II functional appliance. Material and Methods: The present study was implemented as a historical cohort with the before and after design. Pre- and post-treatment lateral cephalometric radiographs of 33 skeletal Class II patients treated with the Farmand II functional appliance were included in the present study. The cephalometric analysis was done by tracing the related lines and landmarks. Facial angles and angles determining the natural head and neck position including craniohorizontal, craniocervical, craniovertical (CCV), and cervical curvature (CCI) were measured. Collected data were entered in Statistical Package for the Social Sciences (SPSS)-version 17 software. Paired t-test was used to evaluate the changes in cephalometric indices before and after treatment. P &lt; 0.05 was defined to be statistically significant for all the tests. Results: The results of the present study, showed a significant reduction in the mean values of A point, nasion, B point (ANB) angle and angle of convexity following treatment (P &lt; 0.001); also, Sella-nasion/Odontoid process tangent (SN/OPT) angle showed a substantial decrease in treated patients (P = 0.033), which is indicative of head flexion following treatment. Moreover, the decrease in the mean values of the craniocervical angles, including True vertical line (NL/VER) and Sella-nasion/true vertical line (SN/VER), suggests downward bending of the head in patients treated with this appliance (P-values of 0.029 and 0.012, respectively). The odontoid process tangent/cervical vertebra tangent (OPT/CVT) angle showed an insignificant increase (P = 0.260). Conclusion: The present study showed that patients treated with the Farmand II functional appliance tend to flex their heads and maintain their cervical vertebra in a more upright and straight position.

Static and dynamic validation of kinect for ergonomic postural analysis using electro-goniometers as a gold standard:A preliminary study.

Evaluation of the working postures and development of new techniques are paramount in reducing the awkward postures and occurrence of musculoskeletal disorders (MSDs). The Kinect sensor, a portable and cost-effective device, appears to be a promising alternative to study work postures. The current study aimed to evaluate the validity of Kinect against the gold-standard instrument (electro-goniometers) for body joint angle measurements. A unique software application was developed to measure the critical body joint angles for postural evaluation by using the Kinect's skeletal tracking feature. The body joint angle data of ten volunteers were measured simultaneously by both Kinect and electro-goniometers. The validation analysis was conducted in both static and dynamic domains of application. Minimal variation was observed between the two techniques, and the Kinect correlated well for upper-arm joint angles of 45∘, 60∘ and 90∘; lower-arm joint angles of 30∘, 45∘, 60∘, and 90∘; straight neck position, neck joint angle at maximum possible flexion; straight trunk position, trunk bend angle at full flexion. In dynamic analysis, four out of five ICC values were > 0.75 except for the upper arm. Discrepancies in the results indicated the disapproval of Kinect for only wrist measurements. The results of the static and dynamic studies gave a sufficient basis to consider the Kinect tool as an alternative to contemporary posture-based ergonomic evaluation methods.

Application of Acupotomy in a Knee Osteoarthritis Model in Rabbit.

Knee osteoarthritis (KOA) is one of the most frequently encountered diseases in the orthopedic department, which seriously reduces the quality of life of people with KOA. Among several pathogenic factors, the biomechanical imbalance of the knee joint is one of the main causes of KOA. Acupotomology believes that restoring the mechanical balance of the knee joint is the key to treating KOA. Clinical studies have shown that acupotomy can effectively reduce pain and improve knee mobility by reducing adhesion, contracture of soft tissues, and stress concentration points in muscles and tendons around the knee joint. In this protocol, we used the modified Videman method to establish a KOA model by immobilizing the left hindlimb in a straight position. We have outlined the method of operation and the precautions related to acupotomy in detail and evaluated the efficacy of acupotomy in conjunction with the theory of "Modulating Muscles and Tendons to Treat Bone Disorders" through the detection of the mechanical properties of quadriceps femoris and tendon, as well as cartilage mechanics and morphology. The results show that acupotomy has a protective effect on cartilage by adjusting the mechanical properties of the soft tissues around the knee joint, improving the cartilage stress environment, and delaying cartilage degeneration.

FAKTOR-FAKTOR YANG MEMPENGARUHI KENYAMANAN DAN KUALITAS PEMAKAI LENSA PROGRESIF

The comfort and quality of vision of progressive lenses are determined by several factors such as the measurement and placement of the lens, the position of the head when examined, and the adjustment of the eyeglass frame when the lens parameters are measured. This research illustrates how the comfort and quality of vision can be affected by these factors. This research was conducted on those who have examined and installed progressive lenses based on their experience and abilities. The results showed that the visual quality of progressive lens wearers was influenced by the measurement of monocular PD, vertical pupils with reference to the lower rim of the rim and the center of the pupil,. head position factor when looking far must be in a straight or primary position, factors that affect the quality of vision where far vision must be clear through progressive lenses , quality near vision must be clear and distance vision medium clear.

Aerodynamic Study of MotoGP Motorcycle Flow Redirectors

In recent years, the introduction of aerodynamic appendages and the study of their aerodynamic performance in MotoGP motorcycles has increased exponentially. It was in 2016, with the introduction of the single electronic control unit, that the search began for alternative methods to generate downforce that were not solely reliant on the motorcycle’s electronics. Since then, all types of spoilers, fins and wings have been observed on the fairings of MotoGP motorcycles. The latest breakthrough has been Ducati’s implementation of flow redirectors at the front and bottom of the fairing. The aim of the present study was to test two hypotheses regarding the performance of the flow redirector by responding to the corresponding research questions on its aerodynamic function and advantage, both in the straight and leaning position. In a preanalytical cognitive act, a visual study of MotoGP motorcycles was conducted and, accordingly, a 3D-CAD model was designed ad hoc in compliance with the FIM 2022 regulations for both the motorcycle and flow redirector. Numerical simulations using OpenFOAM software were then carried out for the aerodynamic analysis. Finally, the Taguchi methodology was applied as an effective simulation-based strategy to narrow down the combinations of geometric parameters, reduce the solution space, optimize the number of simulations, and statistically analyse the results. The aerodynamic performance of the flow redirector is highly dependent on the inlet flow when the motorcycle is in a straight position. The results indicate that all models with leaned motorcycle bearing the flow redirector, regardless of geometry, have an aerodynamic advantage, as the appendage generates downforce with a minimal increment of the drag coefficient. In a cornering situation, the flow separator in the flow redirector reduces the disadvantageous influence of wheel rotation on the “diffuser effect” by drawing the flow towards the outside of the curve, creating extra downforce.

The relationship between the PICC tip position and weight gain, length growth of premature infants under ultrasonography: a correlation analysis study.

This study aimed to analyze the correlation between PICC tip position and weight/length changes in preterm infants in different positions using ultrasonography. The study is a prospective before and after self-control clinical trial. The study analyzed the distance between the PICC tip and the entrance of the heart under ultrasonography for premature infants who underwent PICC insertion. The infants were positioned and tracked weekly, and their weight and length were recorded. The Spearman rank correlation test was used to analyze the relationship between the displacement distance of the PICC tip under ultrasonography in different positions and weight/length changes. A total of 202 premature infants were included in the study, and 100% of them experienced changes in the PICC tip position. During the first week, 134 (66.33%) cases in a flexed position and 153 (75.74%) cases in a straight position showed displacement of the catheter toward the heart. The displacement distance of the tip during catheter retention was significantly correlated with weight change (rs = 0.681/0.661, P < 0.05) and length change (rs = 0.629/0.617, P < 0.05). In the third and fifth weeks, weight increased by 451 ± 178 and 750 (715-975) g, length increased by 1.50 (1.00-2.12) and 3.00 (2.00-3.70) cm, the catheter moved 1.27 ± 0.89 and 2.23 ± 0.95 cm, respectively, in a flexed position. The PICC tip position in preterm infants is influenced by weight and length changes. It is crucial to use ultrasonography to track and locate the catheter within the first week of placement and to increase the frequency of catheter localization starting from the third and fifth weeks. The flexed position is recommended during catheter localization.

Detailed Investigation of Knee Biomechanics during Posture Maintenance while Applying Different Static Loadings on the Spine

The aim of this paper was to investigate in detail the biomechanics of the knee during different static loadings on the spine using electromyographic (EMG) signals from six main surface muscles acting in the knee joint; three components of the ground reaction force measured by a force plate; knee flexion joint angle measured by a flexible goniometer; and the distances between the bones (femur and tibia) forming the knee joint measured by an echograph. The measurements were taken without weight (reference straight position) and with a weight of 2, 5, 10, 15, 17, and 20 kg placed in a rucksack on the spine. The results showed that the forces in the horizontal and sagittal planes were negligible, and the reaction in the frontal plane increased and was linearly dependent on the carrying weight. The distance between bones decreased linearly with increasing weight for all participants from 3.94% to 53.92% from the referent position. The knee angle varied and in many cases decreased with increasing weight. The calculated correlation coefficients between mean EMG signals and loading weight showed that the adjustment of different subjects’ musculature to increasing load is individual. In general, knee joint balance is a dynamic individual process.

METHODOLOGICAL ASPECTS OF THE APPLICATION OF SPECIAL AND PREVENTIVE EXERCISES FOR THE MUSCLES OF THE LOWER EXTREMITIES

We considered the structure of the movement of the segments of the kinematic links of the belt of the lower limbs. Medical and biological studies were conducted in the exercises "flexion, abduction, adduction, extension of the hip while standing." The optimal positions for the manifestations of the muscles of the front, medial, and back groups of the thigh are determined; external muscles of the pelvic girdle of maximum contractile capabilities. This position is the coaxial straight position of the supporting limb and trunk. We determined the initial conditions and determined the basic conditions for the use of complexes of special preventive exercises using special equipment with an unstable surface. An additional, destabilizing position of the body, an external factor - the tension of the rubber cable - was also involved. The specified conditions for the use of exercises were strictly regulated and systematized into complexes, methodically described and differentiated depending on the change in the position and direction of movement of the limb. The exercises considered in this paper can be used as preventive measures for the muscles of the musculoskeletal system and joints. It will also be effective to use the proposed movement elements in the structure of rehabilitation measures for injuries or diseases of the muscles of the lower limbs and back.

Elevated In Vivo ACL Strain Is Associated With a Straight Knee in Both the Sagittal and the Coronal Planes

Background: Noncontact anterior cruciate ligament (ACL) injuries typically occur during deceleration movements such as landing or cutting. However, conflicting data have left the kinematic mechanisms leading to these injuries unclear. Quantifying the influence of sagittal and coronal plane knee kinematics on in vivo ACL strain may help to elucidate noncontact ACL injury mechanisms. Purpose/Hypothesis: The purpose of this study was to measure in vivo sagittal and coronal plane knee kinematics and ACL strain during a single-leg jump. We hypothesized that ACL strain would be modulated primarily by motion in the sagittal plane and that limited coronal plane motion would be measured during this activity. Study Design: Descriptive laboratory study. Methods: Seventeen healthy participants (8 male/9 female) underwent magnetic resonance imaging (MRI) followed by high-speed biplanar radiography, obtained as participants performed a single-leg jump. Three-dimensional models of the femur, tibia, and associated ACL attachment site footprints were created from the MRIs and registered to the radiographs to reproduce the position of the knee during the jump. ACL strain, knee flexion/extension angles, and varus/valgus angles were measured throughout the jump. Spearman rank correlations were used to assess relationships between mean ACL strain and kinematic variables. Results: Mean ACL strain increased with decreasing knee flexion angle (ρ = −0.3; P = .002), and local maxima in ACL strain occurred with the knee in a straight position in both the sagittal and the coronal planes. In addition, limited coronal plane motion (varus/valgus angle) was measured during this activity (mean ± SD, −0.5°± 0.3°). Furthermore, we did not detect a statistically significant relationship between ACL strain and varus/valgus angle (ρ = −0.01; P = .9). Conclusion: ACL strain was maximized when the knee was in a straight position in both the sagittal and coronal planes. Participants remained in <1° of varus/valgus position on average throughout the jump. As a ligament under elevated strain is more vulnerable to injury, landing on a straight knee may be an important risk factor for ACL rupture. Clinical Relevance: These data may improve understanding of risk factors for noncontact ACL injury, which may be useful in designing ACL injury prevention programs.

Measurement of spinopelvic sagittal alignment in the relaxed seated position rather than in the straight seated position is suitable for assessing spinopelvic mobility in patients before total hip arthroplasty

The relationship between spinopelvic mobility and dislocation in total hip arthroplasty (THA) has recently attracted attention. This study aimed to investigate the differences in sacral slope (SS) between two types of upright seated positions and to determine which seated position was appropriate for assessing spinopelvic mobility (change in SS from standing to sitting) before THA. This prospective cohort study included 75 hips from 75 patients who had undergone primary THA. Each patient underwent preoperative lateral spinopelvic radiography in standing (st) and two seated positions: relaxed (rs) and straight (ss). The change in SS between each position (Δ) was measured. Differences in all spinopelvic sagittal alignment parameters between the two seated positions were statistically significant (p<0.001). The range, median, and mean values of ΔSSss-rs were -2.0° to 26.5°, 6.8°, and 8.3°, respectively. ΔSSss-rs was significantly correlated with SS, LLA, and PFA in the relaxed seated position (r=-0.52, -0.39, and 0.37; p<0.001, p<0.001, and p=0.001, respectively), but was not correlated to these parameters in the straight seated position. Of the 52 patients with normal spinopelvic mobility in the relaxed seated position (ΔSSst-rs>10°), 24 (46%) patients were misrepresented as having a stiff spine in the straight seated position (ΔSSst-ss<10°). The change in SS from the straight to the relaxed seated position widely varied in patients before THA. The spinopelvic radiograph in the relaxed seated position is appropriate when evaluating spinopelvic mobility for preoperative planning.

Study of Thoracic and Lumbar Spine Kinematics When Using Tipton Chair: A Repeated-measures Study in Healthy Young Adults

Objective: The effectiveness of the Tipton chair on the thoracic and lumbar spine of students was evaluated in the straight upright position and careful study postures. Materials &amp; Methods: This study was performed on 30 students (20 women and 10 men) who had no history of musculoskeletal disorders. Evaluation of changes in the angles of the thoracic and lumbar spinal was performed using an electrogoniometer on the normal and Tipton chair in the two postures of straight upright and careful study. The participants were evaluated in each posture on each chair for five minutes. Considering the resting time and questionnaire completion, the study took 30 minutes for each person. The data recorded by the electrogoniometer were analyzed through repeated measures statistical test and data of the system usability scale (SUS) questionnaire by the paired t-test in SPSS software, version 25. Results: The mean range of changes in the angles of the thoracic spine in the sagittal plane showed that the variable of chair type was not significant (P=0.072), but the variable of posture was (P=0.013). Also, regarding the mean range of change in thoracic lateral flexion, the interaction of chair and posture (P=0.048) and the chair variable with (P=0.003) had a significant difference. This difference was about a 28% reduction in the mean range of changes in the lateral flexion of the thoracic spine in the upright posture and a 10% reduction in the careful study posture in the Tipton chair compared to the normal chair. While the posture variable had no significant difference (P=0.705). Also, the mean range of changes in lumbar flexion extension showed that the chair variable (P=0.003) had a significant difference. This significant difference was about a 16% reduction in the mean range of changes in the flexion extension of the lumbar spine in the upright posture and a 43% reduction in the careful study posture in the Tipton chair compared to the normal chair. While the variable of posture (P=0.162) did not have significant differences. The study's results on lateral lumbar flexion also showed that both variables of chair and posture had a significant difference (P=0.009). The mean range of changes in lumbar lateral flexion angles in both upright and careful posture in the Tipton chair was reduced by 28% compared to the normal chair. Analysis of SUS questionnaire scores for the Tipton and normal chairs showed a significant difference between these two chairs (P=0.000). In addition, the average scores of the SUS questionnaire were 78.6 for the Tipton chair and 65.9 for the normal chair, which shows an increase of 19%. Conclusion: The results of the present study showed that the Tipton chair could reduce the average range of body angles in the thoracic and lumbar spine. Also, the study results indicated an increase in user satisfaction with the Tipton chair compared to the normal chair, in which the level of satisfaction of women is higher than men. It can be due to the difference in anthropometric dimensions between women and men.

The Predicted Position of the Knee Near the Time of ACL Rupture Is Similar Between 2 Commonly Observed Patterns of Bone Bruising on MRI

Background: Bone bruises observed on magnetic resonance imaging (MRI) can provide insight into the mechanisms of noncontact anterior cruciate ligament (ACL) injury. However, it remains unclear whether the position of the knee near the time of injury differs between patients evaluated with different patterns of bone bruising, particularly with regard to valgus angles. Hypothesis: The position of the knee near the time of injury is similar between patients evaluated with 2 commonly occurring patterns of bone bruising. Study Design: Descriptive laboratory study. Methods: Clinical T2- and T1-weighted MRI scans obtained within 6 weeks of noncontact ACL rupture were reviewed. Patients had either 3 (n = 20) or 4 (n = 30) bone bruises. Patients in the 4–bone bruise group had bruising of the medial and lateral compartments of the femur and tibia, whereas patients in the 3–bone bruise group did not have a bruise on the medial femoral condyle. The outer contours of the bones and associated bruises were segmented from the MRI scans and used to create 3-dimensional surface models. For each patient, the position of the knee near the time of injury was predicted by moving the tibial model relative to the femoral model to maximize the overlap of the tibiofemoral bone bruises. Logistic regressions (adjusted for sex, age, and presence of medial collateral ligament injury) were used to assess relationships between predicted injury position (quantified in terms of knee flexion angle, valgus angle, internal rotation angle, and anterior tibial translation) and bone bruise group. Results: The predicted injury position for patients in both groups involved a flexion angle <20°, anterior translation >20 mm, valgus angle <10°, and internal rotation angle <10°. The injury position for the 3–bone bruise group involved less flexion (odds ratio [OR], 0.914; 95% CI, 0.846-0.987; P = .02) and internal rotation (OR, 0.832; 95% CI, 0.739-0.937; P = .002) as compared with patients with 4 bone bruises. Conclusion: The predicted position of injury for patients displaying both 3 and 4 bone bruises involved substantial anterior tibial translation (>20 mm), with the knee in a straight position in both the sagittal (<20°) and the coronal (<10°) planes. Clinical Relevance: Landing on a straight knee with subsequent anterior tibial translation is a potential mechanism of noncontact ACL injury.