Internal Torsion Research Articles

Evaluation of bone deformities of the femur, tibia, and patella in Toy Poodles with medial patellar luxation using computed tomography.

To evaluate morphological parameters of the femur, tibia, and patella in Toy Poodles with medial patellar luxation (MPL) using three-dimensional (3D) computed tomography (CT) and to compare these parameters between radiography and CT. Thirty-five hindlimbs of Toy Poodles were divided into normal and grade 2 and 4 MPL groups. The anatomical and mechanical lateral proximal femoral angle, anatomical and mechanical lateral distal femoral angle (aLDFA, mLDFA), femoral varus angle (FVA), inclination of the femoral head angle, procurvation angle, anteversion angle (AA), frontal angle of the femoral neck, mechanical medial proximal or distal tibial angle, mechanical cranial proximal or distal tibial angle, tibial plateau angle, tibial torsion angle (TTA), Z angle, relative tibial tuberosity width, ratio of the medial distance of tibial tuberosity to the proximal tibial width (MDTT/PTW), patella size, and the patellar ligament length: patellar length (L:P) ratio were evaluated on radiography and 3D CT. The aLDFA, mLDFA, FVA, and TTA were significantly larger and the AA, MDTT/PTW, and patella were significantly smaller in the grade 4 MPL group. There were significant differences in many parameters between imaging tools, and CT was considered less susceptible to potential artefacts and rotational deformities. Toy Poodles with grade 4 MPL had significant femoral varus deformity, medial displacement of the tibial tuberosity, internal torsion of the proximal tibia, and hypoplasia of the patella.

Investigating the relationship between internal tibial torsion and medial collateral ligament injury in patients undergoing knee arthroscopy due to tears in the posterior one third of the medial meniscus

PurposeTo evaluate the relationship between medial collateral ligament (MCL) injury and degree of internal tibial torsion in patients who had undergone arthroscopic resection due to tears in the posterior one third of the medial meniscus. MethodsSeventy-one patients were allocated into two groups with respect to foot femur angle (FFA) and transmalleolar angle (TMA) (Group 1 31 patients with FFA<8° and Group 2 40 patients with FFA≥8°). The groups were compared in terms of valgus instability, Lysholm score, magnetic resonance view, FFA, and TMA, both before and after the operation. ResultsLysholm scores were higher in Group 2 at both postoperative week 1 (p<0.001) and month 1 (p=0.045) relative to Group 1. Preoperative cartilage injury was encountered more frequently in Group 1 (p=0.037) than in Group 2. MCL injury was detected more frequently in Group 1 compared to Group 2 postoperatively at week 1 (p=0.001). ConclusionWe conclude that FFA and TFA, indicators of internal tibial torsion, may serve as markers for foreseeing clinical improvement and complications following arthroscopic surgery. Level of Evidencelevel III retrospective comparative study.

Predictor factors for lower extremity malalignment and non-contact anterior cruciate ligament injuries in male athletes.

The aim of this study was to determine the predictor factors concerning the lower extremity alignment in non-contact anterior cruciate ligament (ACL) injuries among male athletes. In a retrospective study, the unilateral navicular drop, the ankle dorsiflexion range of motion (ROM), internal tibia torsion, knee genu recurvatum, quadriceps angle, hip internal and external rotation ROM and hip anteversion were measured in 53 subjects with complete ACL injury and compared with these accepted standard values. To identify predictor factors for lower extremity alignment and non-contact ACL injuries in male athletes, a multiple logistic regression analysis method was performed. All the subjects were primarily assessed with activity modification and without an ACL reconstruction. The results of this study showed significant predictor correlations between the independent variables, ankle dorsiflexion, hip internal rotation and hip anteversion (p<0.05). However, the differences in navicular drop, internal tibia torsion, knee hyperextension, Q angle and hip external rotation were non-significant. According to these findings, a decreased ROM in ankle dorsiflexion, hip internal rotation and increased hip anteversion appeared to be statistically significant predictors for developing non-contact ACL ligament injuries in male athletes. Based on the results of this study, significant predictor factors between lower extremity alignment and ACL injuries are clinically relevant as it confirms the existence of increased injury risk with certain patterns of skeletal alignment. II.

Pruning the Hamiltonian Matrix in MULTIMODE: Test for C2H4 and Application to CH3NO2 Using a New Ab Initio Potential Energy Surface.

We report vibrational self-consistent field/virtual state configuration interaction energies of nitromethane using the code MULTIMODE and a new full-dimensional potential energy surface (PES). The PES is a precise, permutationally invariant linear least-squares fit to 17,049 electronic energies, using the CCSD(T)-F12b method with HaDZ basis (cc-pVDZ basis for H atoms, and aug-cc-pVDZ basis for C, O, N atoms). Nitromethane has 15 vibrational degrees of freedom, including one that is a nearly free internal methyl torsion, which is accurately described by the PES. This torsional mode makes vibrational calculations very challenging and here we present the results of calculations without it. Nevertheless, 14-mode calculations are still challenging and can lead to very large Hamiltonian matrices. To address this issue, we apply a pruning scheme, suggested previously by Handy and Carter, that reduces the size of matrix without sacrificing accuracy in the eigenvalues. The method is briefly described here in the context of partitioning theory. A new and more efficient implementation of it, coded in the latest version of MULTIMODE program, is described. The accuracy and efficiency are demonstrated for 12-mode C2H4 and then applied to CH3NO2. Agreement with available experimental values of the CH3NO2 14 fundamentals is very good. Diffusion Monte Carlo calculations in full dimensionality are done for the zero-point energy and wavefuction. These indicate that the torisonal motion is nearly a free-rotor in this state.

A beam formulation for large displacement analysis of composite frames with semi-rigid connections

This paper presents a geometrically non-linear beam formulation for large displacement analysis of composite beam type structures with semi-rigid connections. Within the framework of updated Lagrangian incremental formulation and the nonlinear displacement field of thin-walled cross-sections, which accounts for restrained warping and the second-order displacement terms due to large rotations, the equilibrium equations of a straight beam element are firstly developed. Due to the nonlinear displacement field, the geometric potential of semitangential moment is obtained for both the internal torsion and bending moments, respectively. To account for the semi-rigid connection behaviour, a special transformation procedure is developed. The laminates are modelled on the basis of classical lamination theory. In order to illustrate the application of the proposed formulation, several numerical examples are presented.

Combined Antero-Posterior Inverted-U Metaphyseal and Open-Wedge Medial-Epiphyseal Osteotomy for Advanced Blount Disease

Background: Blount disease is frequently associated with deformities that may not be adequately corrected by a single metaphyseal osteotomy. This study evaluated the outcome of a combined metaphyseal and epiphyseal osteotomy in severe cases. Methods: We prospectively evaluated the outcome of combining the antero-posterior inverted-U metaphyseal osteotomy with a medial open-wedge hemi-epiphyseal osteotomy in eighteen patients (27 tibiae) with Stage IV to VI Blount disease. Results: The average age of patients was 9 years (ranging from 5 to 17). The tibio-femoral angle improved from 43° varus (Range: 34° - 78°) to 2° varus (Range: 5° valgus to 8° varus). The metaphyseal-diaphyseal angle improved from 36° to 8° varus. Internal tibial torsion improved from 39° to 2°. All the patients were able to achieve 110° of knee flexion in a year. Conclusion: In conclusion, the combined metaphyseal and epiphyseal osteotomy satisfactorily corrected tibio-femoral and metaphyseal-diaphyseal varus and internal tibial torsion without recurrence in patients with severe Blount disease. Level of Evidence: IV.

Orthosis Effects on the Gait of a Child with Infantile Tibia Vara

Infantile tibia vara (ITV) is an acquired form of tibial deformity associated with tibial varus and internal torsion. As there is currently insufficient data available on the effects of orthotics on gait parameters, this study aimed to document the influence of orthosis on walking. A male infant with bilateral tibia vara used orthoses for five months. Gait evaluations were performed pre- and posttreatment for both legs. The kinematic parameters were collected by using a motion analysis system. The orthotic design principle was used to correct the femur and tibia. Posttreatment gait parameters were improved compared to pretreatment parameters. After 5 months, there was remarkable change in the stance-phase degrees of frontal plane hip joint abduction and knee joint varus. We found that orthoses were an effective treatment for the infantile tibia vara gait characteristics in this patient. Full-time use of single, upright knee-ankle-foot orthosis with a drop lock knee joint and application of corrective forces at five points along the full length of the limb were effective.

Tibial torsion; does it differ in children with congenital talipes equinovarus (ctev) compared to normal ones?

Background: Congenital talipes equinovarus (CTEV) or clubfoot is one of the commonest congenital orthopaedic conditions requiring intensive treatment. A typical clubfoot consists of a deformed foot in equinus ,varus, adduction. In some cases a cavus component is also there. Tibial torsion is the angle between the transverse axes of the proximal and distal tibial articular surfaces. Controversy exists concerning the presence or absence of excessive medial or internal tibial torsion in CTEV. Materials & Methods: A cross sectional study was done of thirty consenting patients with CTEV and thirty children with injuries not involving the tibia or fibula selected by convenience sampling attending the orthopaedic clinic of a tertiary care hospital of Western Maharashtra . We measured the angular difference between the proximal and distal posterior tibial planes as defined by ultrasound scans thus minimising the error introduced by the posterior shifting of lower end fibula in the fibular notch after manipulative correction. The data was entered in excel and appropriate statistic test was applied. Results: The mean external torsion of the tibia in children with CTEV was 18 degrees (standard deviation 2.7), which was significantly less than the mean external torsion of tibia in normal children (38.13 degrees; standard deviation 9.194) (p<0.05). Conclusions: The children with CTEV have a relative tibial intorsion, as compared to normal children.

Torsional osteotomies of the femur.

Various pathologies of the hip or knee, such as patellofemoral malalignment or femoroacetabular impingement may be caused by a femoral torsional deformity. When diagnosed and analyzed, it is treated by femoral torsional osteotomy. Thirty femoral torsional osteotomies in 25 patients were included, the principal symptoms were patellar dislocation in 15 patients, anterior knee pain in 17, and femoroacetabular impingement in two. A computed-tomography-based measurement of the torsional angle was performed in all patients. Japanese Knee Society score, Tegner activity score, Lysholm score, and visual analog scale score were determined before surgery and at follow-up after 41 (6-113) months. Femoral internal torsion was on average 40.9° (29° - 66°; normal 24°). Surgical treatment consisted of a femoral external torsional osteotomy of on average 13.8° (5° - 26°). Tegner activity score increased non-significantly (p-value 0.326) from 3.57 to 3.71. Japanese Knee Society score improved significantly from 72 to 87 (p-value 0.004) while Lysholm score rose significantly from 66 to 84 points (p-value 0.004). Pain relief was demonstrated by a significant decrease in the VAS score from 5.6 to 2.4 (p-value 0.007). No further patellar dislocation was reported. Torsional deformities of the femur frequently cause symptoms in the knee or hip joint. After thorough assessment and diagnostic investigation, a femoral external torsional osteotomy provides significant pain relief as well as patellofemoral stability.

Buckling analysis of thin-walled functionally graded sandwich box beams

Buckling analysis of thin-walled functionally graded (FG) sandwich box beams is investigated. Material properties of the beam are assumed to be graded through the wall thickness. The Euler-Bernoully beam theory for bending and the Vlasov theory for torsion are applied. The non-linear stability analysis is performed in framework of updated Lagrangian formulation. In order to insure the geometric potential of semitangental type for internal bending and torsion moments, the non-linear displacement field of thin-walled cross-section is adopted. Numerical results are obtained for FG sandwich box beams with simply–supported, clamped–free and clamped–clamped boundary conditions to investigate effects of the power-law index and skin-core-skin thickness ratios on the critical buckling loads and post-buckling responses. Numerical results show that the above-mentioned effects play very important role on the buckling analysis of sandwich box beams.

Integrable hydrodynamic equations for initial chiral currents and infinite hydrodynamic chains from WZNW model and string model of WZNW type with SU(2), SO(3), SP(2), SU(∞), SO(∞), SP(∞) constant torsions

The WZNW and string models are considered in terms of the initial and invariant chiral currents assuming that the internal and external torsions coincide (anticoincide) and they are the structure constants of the SU(n), SO(n), SP(n) Lie algebras. These models are the auxiliary problems in order to construct integrable equations of hydrodynamic type. It was shown that the WZNW and string models in terms of invariant chiral currents are integrable for the constant torsion associated with the structure constants of the SU(2), SO(3), SP(2) and SU(3) algebras only. The equation of motion for the density of the first Casimir operator was obtained in the form of the inviscid Burgers equation. The solution of this equation is presented through the Lambert function. Also, a new equation of motion for the initial chiral current was found. The integrable infinite hydrodynamic chains obtained from the WZNW and string models are given in terms of invariant chiral currents with the SU(2), SO(3), SP(2) and with SU(∞), SO(∞), SP(∞) constant torsions. Also, the equations of motion for the density of any Casimir operator and new infinite-dimensional equations of hydrodynamic type for the initial chiral currents through the symmetric structure constant of SU(∞), SO(∞), SP(∞) algebras are obtained.

Modulating the magnetosphere of magnetars by internal magneto-elastic oscillations

We couple internal torsional, magneto-elastic oscillations of highly magnetized neutron stars (magnetars) to their magnetospheres. The corresponding axisymmetric perturbations of the external magnetic field configuration evolve as a sequence of linear, force-free equilibria that are completely determined by the background magnetic field configuration and by the perturbations of the magnetic field at the surface. The perturbations are obtained from simulations of magneto-elastic oscillations in the interior of the magnetar. While such oscillations can excite travelling Alfv\'en waves in the exterior of the star only in a very limited region close to the poles, they still modulate the near magnetosphere by inducing a time-dependent twist between the foot-points of closed magnetic field lines that exit the star at a polar angle $\gtrsim 0.19\,$rad. Moreover, we find that for a dipole-like background magnetic field configuration the magnetic field modulations in the magnetosphere, driven by internal oscillations, can only be symmetric with respect to the equator. This is in agreement with our previous findings, where we interpreted the observed quasi-periodic oscillations in the X-ray tail of magnetar bursts as driven by the family of internal magneto-elastic oscillations with symmetric magnetic field perturbations.

Surgical Management of Persistent Intoeing Gait Due to Increased Internal Tibial Torsion in Children

Intoeing gait is frequently seen in developing children, and in most cases it resolves with growth. However, persistent, extreme intoeing gait, due to increased internal tibial torsion, may disrupt gait function. At our institution, children with symptomatic intoeing gait are evaluated per a standardized protocol, which includes quantitative gait analysis. When the primary cause is increased internal tibial torsion, surgical correction by supramalleolar tibial rotational osteotomy is recommended. The study design was a retrospective case series, with normative controls (31 children), of typically developing children with symptomatic intoeing gait who were treated by isolated supramalleolar tibial rotation osteotomy (28 children, with 45 treated extremities). Preoperative and 1-year postoperative physical examination, kinematic, kinetic, and pedobarographic data were compared. Patient-reported and parent-reported outcomes in functional and satisfaction domains were assessed by items on a 7-point questionnaire. Internal tibial torsion, foot progression angle, and knee rotation were normalized following tibial rotation osteotomy. Compensatory external hip rotation and external knee progression angle were significantly improved but not normalized following tibial rotation osteotomy. An increased coronal plane knee varus moment was significantly decreased following surgery. Increased sagittal and transverse plane knee moments were significantly decreased but not normalized following surgery. Significant improvements were observed with respect to tripping, falling, foot/ankle pain, and knee pain following surgery. Children with symptomatic intoeing gait because of increased internal tibial torsion have characteristic primary and compensatory kinematic gait deviations that result in increased loading about the knee during the stance phase of gait. Correction of the internal tibial torsion by rotation osteotomy improves, but does not normalize, all the kinematic and kinetic gait deviations associated with intoeing gait. The association between increased internal tibial torsion and degenerative arthritis of the knee in adults may be a consequence of longstanding increased loading of the knee joint due to the kinematic gait deviations seen with intoeing gait. Therapeutic intervention, level III.

Compensatory muscle activation during walking in adolescents with excessive external and internal tibial torsion

Introduction and aim: In previous studies it has been postulated that excessive tibial torsion (TT) leads to a reduced ability of muscles to extend the knee due to lever arm dysfunction. This may contribute to crouch gait [1,2]. Although the soleus crosses the ankle joint it has also the potential to extend both the knee and the hipwhileworking against gravity [1,3]. To date the effects of excessive external and internal TT on muscles which extend the stance limb during walking has not been investigated by SEMG. Patients/materials and methods: Gait analysis data of 8 patients (mean 13.2 yrs) and 11 legs resp. 16 patients (mean 12.3 yrs) and 23 legs with CT-diagnosed external (mean 49◦) and internal (mean 17◦) TT were studied retrospectively. Exclusion criteria were age 18 years, leg length discrepancy >1 cm, foot deformities, neurological diseases, scoliosis >10◦ and obesity (>PCTL 90). Bilateral SEMG signals (12-channel-wireless, 1000Hz, Noraxon) were examined from vastus medialis (VM), medial hamstrings (MH), and gastrocnemius medialis (GM). For each patient three gait cycles were analysed by means of on/off analysis. Principal Component Analysis (PCA) was used to compare transversal hip kinematic (8 cameras, VICON) between each patient group and 17 healthy, age-matched subjects in order to analyse possible influence on the electromyographic activity. Linear mixed models applied to PC-scores were used to determine the main effects within retained principal components (PCs). Results: An additional activity has been measured during the last 20% of the stance phase in 5 (VM) resp. 2 (MH) of 8 patients with increased TT and in 6 (VM) resp. 7 (MH) of 16 patients with decreased TT. The GM also showed an abnormal SEMG in terms of premature activity at the beginning and at the end of the gait cycle in a total of 13 patients. Hip transversal kinematic was not different between patients with decreased TT and healthy controls (hip PC1: 74.4%, p= .272) in this small sample. However, patients with increased TT rotated the hip significantly more internally during the overall gait cycle compared to the healthy control group (PC1: 72.5%, p< .001) (Fig. 1). Discussion and conclusion: In patientswith excessive external or internal TTwe could show that VMandMHwork actively against the lever armdysfunctionofplantarflexors to support theextension of the knee and hip. In order to compensate for the external foot progression angle, patients with increased TTmay also activate the MH to rotate the hip internally. Activity of gastrocnemius medialis has also been seen as a compensation of lever arm dysfunction. We conclude that patients with abnormal external or internal TT need to strengthen their quadriceps and hamstrings beside the plantar flexors in case of weakness of these muscles.

Biplanar supracondylar femoral derotation osteotomy for patellofemoral malalignment: the anterior closed-wedge technique.

Patellofemoral malalignment can be caused by several factors including increased internal torsion of the femur. As a causative treatment method, supracondylar femoral derotation osteotomies have been proposed. For valgus- and varus-producing supracondylar femoral osteotomies, a biplanar osteotomy has been introduced in order to enhance primary fixation stability and osseous consolidation by increased bone-to-bone contact. In this article, a modification of this technique is described, which allows for a biplanar supracondylar femoral derotation osteotomy. V.

Quinquephenyl: the simplest rigid-rod-like nematic liquid crystal, or is it? An atomistic simulation.

We have performed an atomistic molecular-dynamics study on the molecular organization and liquid-crystalline properties of quinquephenyl (P5), a prototypical mesogen that is of interest for organic electronics. The thermotropic behavior reveals different mesophases. When cooling down from the isotropic phase, a transition to nematic (≈715 K) is found, then a smectic SA (≈657 K) and another smectic, SXA (≈642 K), before a crystalline phase is recovered (≈617 K). This phase sequence is compared with experimental findings. The different phases are described in terms of their molecular organization, orientational and positional order parameters, and pair distribution functions, as well as of their dynamics properties. In particular, the smectic phases that have not yet been characterized experimentally are discussed. By analyzing the effective shape of P5, it is concluded that its internal torsions and bending make it less rigid than could be expected.

Global buckling analysis model for thin-walled composite laminated beam type structures

This paper presents a beam finite element model for non-linear global buckling analysis of composite laminated beam type structures. To perform the non-linear stability analysis, the framework of updated Lagrangian incremental formulation is used. The non-linear displacement field of thin-walled cross-section is adopted in order to insure the geometric potential of semitangential type for both the internal torsion and bending moments. The cross-section mid-line contour is assumed to remain not deformed in its own plane and the shear strains of middle surface are neglected. The laminates are modeled on the basis of classical lamination theory. In order to illustrate the application of the proposed formulation, several numerical examples are presented. For validation purposes, the obtained results are compared with results reported in the literature and the ones obtained with shell finite elements by Nastran.

English

In this work, 3D model of D2 dopamine receptor was determined by comparative homology modeling program MODELLER. The computed model's energy was minimized and validated using PROCHECK and Errat tool to obtain a stable model structure and was submitted in Protein Model Database (PMDB-ID: PM0079251). Stable model was used for molecular docking against Risperidone and their 15 derivatives using AutoDock 4.2, which resulted in energy-based descriptors such as Binding Energy, Ligand Efficiency, Inhib Constant, Intermol energy, vdW + Hbond + desolv Energy, Electrostatic Energy, Total Internal Energy and Torsional Energy. After that, we have built quantitative structure activity relationship (QSAR) model, which was trained and tested on Risperidone and their 15 derivatives having activity value pKi in µM. For QSAR modeling, Multiple Linear Regression model was engendered using energy-based descriptors yielding correlation coefficient r2 of 0.513. To assess the predictive performance of QSAR models, different cross-validation procedures were adopted. Our results suggests that ligand-receptor binding interactions for D2 employing QSAR modeling seems to be a promising approach for prediction of pKi value of novel antagonists against D2 receptor.

The therapeutic effect of tibia counter rotator with toe-out gait plate in the treatment of tibial internal torsion in children.

ObjectiveTo evaluate the therapeutic effect of a Tibia Counter Rotator (TCR) with toe-out gait plate (GP) upon tibial internal torsion by a comparative analysis of transmalleolar angle (TMA) and gait analysis with GP alone.MethodsTwenty participants with tibial internal torsion were recruited for this study. Each 10 participants were included in group A with TCR and GP application and in group B with GP application only. The TMA and the kinematic results were used for the evaluation of the therapeutic effects of orthoses.ResultsWithin each group, TMA showed a significant increase after treatment. Group A showed a continuous improvement up to six months, however, group B showed an improvement up to five months only. Group A showed a significantly higher correction effect than group B after treatment. Regarding kinematic data, both groups showed a significantly decreased mean ankle adduction angle after treatment. However, group A showed a significantly lower mean ankle adduction angle than group B after six months.ConclusionThe group with TCR and GP showed a significantly better outcome and continued correction force compared to the group with GP only. Our results suggest that TCR with GP may be useful therapeutic orthoses for children with tibial internal torsion.

Obtaining Detailed Structural Information about Supramolecular Systems on Surfaces by Combining High-Resolution Force Microscopy with ab Initio Calculations

State-of-the art experimental techniques such as scanning tunneling microscopy have great difficulties in extracting detailed structural information about molecules adsorbed on surfaces. By combining atomic force microscopy and Kelvin probe force microscopy with ab initio calculations, we demonstrate that we can obtain a wealth of detailed structural information about the molecule itself and its environment. Studying an FFPB molecule on a gold surface, we are able to determine its exact location on the surface, the nature of its bonding properties with neighboring molecules that lead to the growth of one-dimensional strips, and the internal torsions and bendings of the molecule.