Rotational Deformity Research Articles

Infantile Blount's disease

ABSTRACT Infantile Blount's disease results in multi-planar proximal tibial deformity consisting of varus, procurvatum, internal rotation and shortening. The deformity is attributed to disordered growth of the posteromedial proximal tibial physis. The aetiology is multifactorial. It is associated with childhood obesity and African ethnicity. The ability to differentiate between infantile Blount's disease and physiological bowing depends on the findings of focused clinical examination, X-ray appearance, tibial metaphyseal-diaphyseal angle and tibial epiphyseal-metaphyseal angle. The gold standard of treatment is proximal tibial metaphyseal corrective osteotomy before the age of 4 years. The limb should be realigned to physiological valgus. The recurrence rate after realignment osteotomy is high. Recurrence is associated with age at osteotomy, obesity, higher Langenskiöld stage and medial physeal slope >60°. The surgical management of severe, recurrent or neglected infantile Blount's disease is challenging. Comprehensive clinical examination and multi-planar deformity analysis with standing long leg X-rays are essential to identify all aspects of the deformity. Distal femur coronal malalignment and significant rotational deformity should be excluded. Knee instability due to intra-articular deformity should be corrected by elevation of the medial tibial plateau. Lateral epiphysiodesis should be done at the same time as medial plateau elevation and when medial growth arrest is certain to prevent recurrence. Level of evidence: Level 5 Keywords: Blount's disease, tibia vara, genu varum, recurrence, obesity

Variability of pelvic axial rotation in patients undergoing total hip arthroplasty.

Pelvic axial rotation affects the functional orientation of an acetabular component. Every 1° of axial rotation changes functional acetabular anteversion by 1°. There is limited information on pelvic rotation in THA patients, since it is difficult to measure on routine radiographs. Therefore, we used spine-to-ankle biplanar radiography to investigate variability in pelvic rotation in patients before and after THA. In 156 patients undergoing primary unilateral THA, we measured preoperative, 6 weeks and 1 year postoperative pelvic rotation in both standing and sitting positions using a biplanar radiography system. Patients with fixed pelvic rotation had a similar magnitude and direction of pelvic rotation in all standing or sitting images. We further identified patients with position-independent or position-dependent fixed pelvic rotation. Pelvic rotation was common in THA patients, with 82 patients (53% of 156 patients) having at least 1 image with > 7° of rotational deformity. 12 patients (8% of 156 patients) had fixed rotation, 6 patients (4%) had position-independent fixed axial rotation and 6 patients (4%) had position-dependent fixed axial rotation. It may be important to recognise whether a THA patient has a fixed pelvic axial rotational deformity, where 1 hip is consistently forward or backward in functional imaging. Fixed rotation will increase or decrease the functional anteversion of an acetabular component depending on THA side. Further research might better characterise associations and predictors of fixed axial rotation and its impact on patient outcomes after THA.

Numerical Research on a Three-Dimensional Solid Element Based on Generalized Elasticity Theory

A finite element equation is established based on generalized elasticity theory by applying a virtual work principle. Then, a penalty function term is added to the virtual work equation by imposing rotation and displacement as independent variables. An 8-node element with full integration, an 8-node element with reduced integration, and a 20-node element with full integration are constructed using difference integration schemes and shape functions. The influences of structural degrees of freedom and the penalty parameter on convergence are analyzed via the three elements. It is shown that the 8-node element with reduction integration and the 20-node element with full integration are convergent, whereas the 8-node element with full integration is divergent. The scale effects of a slender beam, a short beam, a thin plate, and a medium-thick plate are numerically analyzed. Lastly, the scale effects of the frequencies that correspond to the bending mode, torsion mode, and tension-compression mode for a pretwisted plate are studied. It is found that the frequencies that correspond to the bending mode and torsion mode exert a scale effect, whereas the frequency that corresponds to the tension-compression mode does not. The essence of the scale effect is that the rotational deformation of the microstructure is amplified.

Experimental analysis of hysteretic behavior and strain field of external diaphragm joints between steel beams and CFDST columns

External diaphragm joints with high structural reliability are used widely in composite steel and concrete structures. In this study, the external diaphragm joint was improved to be a steel beam-to-concrete filled double steel tubular column connection. The digital speckle correlation method was used to measure and investigate the strain field in the panel zone and relative beam-to-column rotation in a low-cycle reciprocating loading test. The obtained hysteresis curves of moment-rotation ( M-θ) and shear force-deformation ( V-[Formula: see text]) showed that the external diaphragm joints had higher strength, higher ductility, and better energy dissipation capacity. Decreasing the axial compression ratio resulted in the deterioration of initial rotational stiffness. Wider external diaphragm produced better ductility and larger initial shear stiffness. The ribbed anchorage web was effective to increase the bending resistance by 10%. Beam-to-column bending stiffness ratio can not only influence the bending resistance and energy dissipation capacity significantly but also affect the shear deformation capacity in the joint core. The magnitude of the shear strain in the panel zone was large, especially for the specimens under column failure mode, and shear deformation in the panel zone should not be neglected for it accounted for 30%–40% of the beam-to-column rotation. Beam-to-column rotation and shear deformation obtained by the digital speckle correlation method offered better predictions to analyze the mechanical behavior of external diaphragm joints in the concrete filled double steel tubular structures.

One-way interfacial waves in aflexuralplate with chiral double resonators.

In this paper, we demonstrate a new approach to control flexural elastic waves in a structured chiral plate. The main focus is on creating one-way interfacial wave propagation at a given frequency by employing double resonators in a doubly periodic flexural system. The resonators consist of two beams attached to gyroscopic spinners, which act to couple flexural and rotational deformations, hence inducing chirality in the system. We show that this elastic structure supports one-way flexural waves, localized at an interface separating two sub-domains with gyroscopes spinning in opposite directions, but with otherwise identical properties. We demonstrate that a special feature of double resonators is in the directional control of wave propagation by varying the value of the gyricity, while keeping the frequency of the external time-harmonic excitation fixed. Conversely, for the same value of gyricity, the direction of wave propagation can be reversed by tuning the frequency of the external excitation. This article is part of the theme issue 'Modelling of dynamic phenomena and localization in structured media (part 2)'.

PO 18271 - New method for the radiographic evaluation of metatarsal rotation in hallux valgus

Introduction: Hallux valgus involves, in addition to I/II intermetatarsal angle deviation, a rotational deformity of the first metatarsal bone and its sesamoids in relation to the ground. The correction of the rotation is the objective of new and recently developed surgical techniques. Objective: To describe a radiographic method that can help predict changes resulting from metatarsal rotational correction and facilitate surgical planning. Methods: We acquired radiographs in a weight-bearing anteroposterior position in patients with flexible hallux valgus while asking the patient to actively extend the toes. We compared the weight-bearing radiographs with and without the toe extension maneuver. In addition to radiography, we performed computed tomography (CT) of the nonweight-bearing active toe extension maneuver using a support platform. To measure the changes, we used the classification of Coughlin and Smith et al. Results: We observed clinical and radiographic correction, both angular and rotational, by measuring the intermetatarsal angle and sesamoid position. The changes were confirmed by CT, which showed improvement in the intermetatarsal angle, sesamoid position and metatarsophalangeal range. Discussion: The toe extension maneuver was described as a peroneus longus tendon activation test by Klemola et al., who used it to demonstrate rotational clinical correction of hallux valgus. Here, we described a radiographic method based on this principle to observe the correction power of and factors involved in metatarsal derotation using a preoperative radiographic technique. Conclusion: The method clearly demonstrated the capacity for the correction of preoperative hallux derotation in various planes, thus helping to predict the clinical, angular and rotational outcomes of surgical treatment.

PO 18074 - Rotational biplanar Chevron osteotomy

Introduction: The Chevron osteotomy is a reliable and popular osteotomy for treating hallux valgus worldwide. Many modifications have been described, but none of them address the rotational deformity of the first metatarsal. The objective of this study is to describe a variation of biplanar Chevron osteotomy that can address first metatarsal rotation when necessary. Methods: The indications for the Rotational Biplanar Chevron Osteotomy (RBCO) are mild to moderate hallux valgus deformity associated with hallux pronation related to internal rotation of the first metatarsal bone. We describe a technique that uses a medial-based wedge parallel to the plantar limb of the osteotomy to free the distal fragment for correct rotation. Results: The more recent concern about hallux valgus surgery represents a very interesting concept that this deformity truly occurs in three different planes, and we may have mistreated the rotation component using current techniques. Many authors have revisited numerous common techniques to adapt them to correct metatarsal pronation. To the best of our knowledge, this is the first paper to describe a modification of the Chevron osteotomy to address rotation of the first metatarsal. Conclusion: We can conclude that rotational biplanar Chevron osteotomy is an useful tool in the treatment of mild hallux valgus associated with metatarsal pronation.

PO 18235 - New tomographic method for measuring metatarsal rotation in hallux valgus

Introduction: Hallux valgus is a 3-dimensional deformity involving an increased intermetatarsal I/II angle and a rotational deformity of the first metatarsal bone. Kim et al. developed a method for measuring the tibial sesamoid position relative to the coronal rotation of the first metatarsal bone in computed tomography scans under simulated weight-bearing conditions. Objective: To describe a method for the topographic assessment of the correction of tibial sesamoid and metatarsal pronation using computed tomography scans under simulated weight-bearing and active toe extension. Method: We performed computed tomography under simulated weight-bearing conditions with and without active toe dorsiflexion, observing the degree of metatarsal pronation and sesamoid subluxation. For measurement purposes, we used the classifications of Kim et al. and Smith et al. Results: We observed tomographic correction, both angular and rotational, by measuring the intermetatarsal angle and tibial sesamoid position, which were confirmed by the change in the alpha angle suggested by Kim et al. Discussion: Toe extension was described as a peroneus longus tendon activation test by Klemola et al., who used this maneuver to demonstrate clinical rotational correction of hallux valgus. We described the use of a tomographic technique that followed this principle to preoperatively observe the underlying factors that may affect the rotational correction of the deformity. Conclusion: The method has the capacity for correction in various planes involving derotation of the first metatarsal bone and the relationship between such derotation and the change in sesamoid position in relation to the coronal plane of the foot.

Is open reduction necessary for pediatric T-condylar fractures of the humerus?

The aim of this study was to investigate the outcomes of closed reduction and percutaneous pinning (Kirschner wire fixation) as a less invasive method for the treatment of pediatric T-condylar fractures of the humerus compared with open reduction and pinning. Among pediatric patients who were diagnosed with T-condylar fractures of the humerus between 2010 and 2017, those who underwent closed reduction and percutaneous pinning were retrospectively evaluated. The surgical technique used was to restore joint alignment through closed reduction and then to insert a pin parallel to the joint surface to stabilize the intercondylar fracture. Then, the supracondylar fracture was fixed with crossed pins. At 1-year follow-up, rotation, angulation, and joint range of motion were evaluated. Patient satisfaction was assessed subjectively using the visual analogue scale. Early and late postoperative Baumann angles were measured. All patients were male, and the mean age was 10.8 ± 4.6 years. The mean follow-up duration was 16.5 ± 7.2 months, and the mean union duration was 7.4 ± 2.3 weeks. None of the patients had any rotational deformities, but two had 5° of varus, one had 5° of valgus, two had a flexion contracture of 10°, and one had a flexion contracture of 40°. The only complication observed was a pin-tract infection, which developed in one patient. The mean visual analogue scale score was 9.25 ± 1. In pediatric patients with T-condylar humerus fractures, closed reduction and percutaneous pinning may be a good alternative to open reduction and pinning, because it is less invasive and does not cause additional complications.

Does Hallux Valgus Exhibit a Deformity Inherent to the First Metatarsal Bone?

Hallux valgus is a common condition, and it still poses some challenges. The identification of factors associated with the development of the deformity is of paramount importance in obtaining a full correction of the disorder. Hallux pronation is one of the frequently found components, especially in larger deformities, but the cause and exact location of this condition are not fully understood. The aim of the present study was to investigate whether there is a rotational deformity inherent to the first metatarsal bone. A case-control study was conducted on patients with and without hallux valgus who were subjected to computed tomography with multiplanar reconstruction. Statistical analysis was performed by means of a mixed model adjusted for foot and gender to compare metatarsal rotation between cases and controls. Correlations between numerical quantitative measurements were investigated by means of Pearson's correlation coefficient obtained in a linear mixed model. A total of 82 feet (tests) were analyzed in the hallux valgus group and 64 feet (tests) in the control group (N = 146). The hallux valgus group was significantly different from the control group (p< .001). Mean metatarsal bone rotation was 15.36° (range 1.65° to 32.52°) in the hallux valgus group and 3.45° (range −7.40° to 15.56°) in the control group. The difference between the means was 11.9° (confidence interval 9.2° to 14.6°). In conclusion, patients with hallux valgus exhibited increased exclusive bone rotation of the first metatarsal toward pronation compared with the population without this condition.

The in-plane dynamic crushing of quadrilateral chiral honeycomb coatings

For the anti-impact performance of hyperelastic coatings covered on the ship hull, the in-plane dynamic crushing behaviors of quadrilateral chiral honeycomb coatings (including chiral and anti-chiral) were numerically studied by explicit dynamic finite element simulations. The deformation mode, energy absorption and supporting reaction force under different impact speeds have been analyzed. The results show that: (1) If the impact speed is low, the chiral honeycomb coatings display the rotational deformation; (2) With the increase of impact speed, the deformation at the top of coating is remarkable; (3) The response of energy absorption and supporting reaction force corresponds to the macroscopic deformation mode of chiral honeycomb coatings.

Numerical Investigation of the Performance of a New Anchored Micropile Structure Against Landslides

As a remedial measure against slope failure, an anchored micropile structure (AMS) was proposed comprising a conventional micropile structure (CMS) and anchor tieback. Numerical investigations of performance of the AMS and CMS were performed. Improvement was observed in the displacement field of slope reinforced by AMS. The rotation deformation of CMS is replaced by flexure deformation in AMS. Displacement of AMS is less than CMS. The tieback acts in both deformation control and stress optimization. The reduction in extreme value of bending moment is equal to 35%. At axial force, the sharing ratio was decreased from 2.43:1 to 1.25:1.

3D printed navigation template-guided minimally invasive percutaneous plate osteosynthesis for distal femoral fracture: A retrospective cohort study

ObjectiveTo evaluate functional and radiological outcomes in distal femoral fracture patients (distal femoral shaft fractures or metaphyseal fractures) receiving indirect reduction and internal fixation with the minimally invasive percutaneous plate osteosynthesis (MIPPO) assisted by 3D printing navigation templates. MethodsThis retrospective study included all adult (≥18 years) patients who underwent MIPPO for distal femoral fracture (AO32/33) at PLA 960 Hospital, Jinan, China between January 1, 2013 and December 31, 2016. 3D printed navigation templates were used to assist surgery. Functional assessment was performed using the Knee Society Score (KSS) and the Functional Knee Society Score (FKSS). Postoperative deformity was assessed with 3D-CT reconstruction using contralateral (non-fracture) side as the reference. ResultsA total of 54 patients underwent MIPPO for distal femoral fracture during the review period (34 and 20 for conventional and template-guided MIPPO, respectively). At 10–14 months, the KSS score was 160.6 ± 18.1 and 167.5 ± 17.2 in the conventional and template-guided MIPPO groups, respectively (p = 0.18). The FKSS was 77.6 ± 9.4 in the conventional MIPPO group vs. 81.0 ± 8.5 in the template-guided MIPPO group (p = 0.15). Femoral length difference was smaller in template-guided MIPPO group (3.31 ± 1.53 vs. 9.50 ± 4.49 mm in the control; p < 0.01). Template-guided MIPPO group also had smaller anatomic lateral distal femoral angle (aLDFA) difference (1.57° ± 0.72° vs. 3.89° ± 1.72° in the control; p < 0.01), anatomic posterior distal femoral angle (aPDFA) difference (1.95° ± 0.78° vs. 5.04° ± 1.78°; p < 0.01), and anteversion angle difference (2.52° ± 1.00° vs. 8.23° ± 4.07°; p < 0.01). The rate of length discrepancy (>20 mm), coronal angulation deformity (aLDFA difference >5°), sagittal angulation deformity (aPDFA difference >10°), and rotational malalignment (anteversion angle >10°) was 5.9%, 20.5%, 2.9%, and 32.4% in the control group. No patients in the template-guided MIPPO group had deformity of any type. ConclusionsMIPPO assisted by 3D printing navigation templates could practically improve surgical accuracy and eliminate postoperative rotational deformity in patients with distal femoral fractures.

Experimental investigation on behavior of reinforced concrete interior beam column joints retrofitted with fiber reinforced polymers

This experimental study is undertaken to study the behavior of RC interior beam-column joints which lack in shear reinforcement and strengthened by FRPs and additional tie bars. The samples are constructed with transverse beams and slab. Total eight models have been prepared of which three joints have been strengthened by carbon FRP (CFRP) fabrics, two joints have been strengthened by CFRP plates and one model has been strengthened by adding tie bar into the joint. The samples have been subjected to incremental cyclic loading provided by hydraulic jacks under constant axial or gravity load and their load-deformation behaviors have been measured by dial gauges and video extensometer. The behaviors of the strengthened joints are compared with the control models. The joints without shear reinforcement undergo brittle failure under cyclic loading. But their ductility increases with increased concrete strength. The joints strengthened by the CFRPs show better load bearing capacity with enhanced ductile behavior. Location of the plastic hinges shifts from column to beam in case of the joints strengthened by CFRP plates and fabrics. The joint strengthened by additional tie bar and micro-concrete undergo large rotational deformation before they fail. Joints strengthened by CFRP fabrics exhibit better ductility and strength than those of the joints retrofitted by CFRP plates and tie bars. Joints strengthened by CFRP plate exhibited high rotational stiffness and are effective in resisting the diagonal crack travelling to transverse beams.

Phase transition induced changes in β-ring rotation and methyl group asymmetric deformation of all-trans-β-carotene

The Raman spectra of all-trans-β-carotene (β-Car) liquefied in dimethyl sulfoxide (DMSO) with the decrease of temperature from 333 K to 263 K were recorded with the aim to reveal the molecular structure properties during phase transition. The CC stretching mode of β-Car shows red shift during liquid and solid phase, while blue shift during the liquid-solid phase transition. The 1425 cm−1 Raman band of DMSO shows the inverse characters for β-Car. Raman shift and intensity in coalescence caused by phase transition are studied by means of density functional theory and the molecular vibration mechanism is found out. The calculated Raman spectra of β-Car and DMSO accurately assign the vibrational modes. The potential energy was calculated to investigate the effect of β-ring rotation on Raman shift during phase transition. The latent 1452 cm−1 Raman band of β-Car crops up when temperature drops to the transformation point of 288 K and the 1425 cm−1 Raman band of DMSO split into two peaks at 1417 cm−1 and 1427 cm−1 after phase transition. Phase transition inducing individual methyl groups vibrations helps to interpret the dwindling intensity of 1425 cm−1 Raman peak of DMSO and the increase of 1452 cm−1 Raman peak of β-Car. A visualisation of nuclear motions is illustrated for better understanding the characteristics of vibronic variations of β-Car molecule in critical phenomena. The implication of these analyses is expected to be helpful for the understanding of the effect of phase transition on biomolecules in solution.

Safety evaluation method of bridge plate rubber bearing based on SVM

In order to comprehensively evaluate the working state and safety performance of the bridge plate rubber bearing (PRB), the basic principle and method of SVM in machine learning theory (Support Vector Machine) was introduced in this paper. Firstly, the performance indices (such as the average compression stress, tangent value of the shear angle and the rotation angle of the PRB) were analyzed and calculated through its finite element model considering the different working conditions (axial compression, shear deformation and the rotation deformation of the PRB). Subsequently, considering the relevant indices affecting the safety performance of the PRB, the Pearson Correlation Coefficients (PCC) were calculated by SVM method for assessing the internal correlation of the performance indices of the PRB for different cases, respectively. The threshold values of the influential factors for different cases considering the PCC and the weight coefficient were obtained for grading the working state of the PRB as five levels. Moreover, in order to verify the validity and suitability of the evaluation of the working state of the plate rubber bearing by the SVM method, three apparent indices for grading the performance level of the PRB such as the crack, the undistributed spalling deformation and the dislocation of the PRB were analyzed and compared with the qualitative descriptions and the quantitative values. Finally, the corresponding threshold values for grading the performance levels of the PRB working states were proposed. It was shown that the SVM based evaluation method for the PRB is feasible and convenient, especially for the bridges with real-time monitoring devices to get the response data of the PRB.

Short Term Radiographic and Patient Outcomes of a Novel Biplanar Plating System for Hallux Valgus Correction

Category:Bunion, Midfoot/ForefootIntroduction/Purpose:Hallux valgus is a complex deformity of the great toe and is a major cause of pain for patients. Despite the variety of techniques, traditional osteotomies often do not address rotational deformities. A novel biplanar plating system was used to perform correction of metatarsal rotation at our institution starting in 2017. The purpose of this study was to determine the correction of rotational deformity and of radiographic parameters, maintenance of this correction (versus recurrence of hallux valgus), complication rates and patient-reported objective survey scores. We sought to determine prognostic factors for successful correction, including age, gender, and time of surgery.Methods:By retrospective chart review, we identified all patients treated by the novel biplanar plating at our institution. We recorded patient demographics, pre-operative range of motion and maltracking, surgical details, operative complications, and any subsequent surgery. Imaging was reviewed at pre-operative and post-operative visits to approximate the hallux valgus angle (HVA), intermetatarsal angle (IMA), and tibial sesamoid position (TSP). Outcome scores (AOFAS, FAAM, SF12 PCS and MCS) pre- operatively and post-operatively at 3 months, 6 months and 12 months were also recorded. The changes in these radiographic parameters and scores were then computed and analyzed to determine if there was an improvement with surgery.Results:Fifty-seven procedures (in 55 patients) were performed and evaluated. There were 8 complications and average follow- up time was 27.1 weeks (+13.8 weeks). Older age was significantly associated with more complications (p = 0.018). Gender and time of surgery did not show any significant association with complications.Radiographic parameters including HVA, IMA, and TSP were analyzed. At 3 and 6 months post-operatively, these parameters were significantly reduced from pre-operative values. At 12 months, there was a trend towards significant reduction (p values of 0.06, 0.06, and 0.053 respectively); however, there were fewer patients who maintained follow-up during this period. The Outcome scores showed improvement post-operatively, but only the AOFAS score showed statistical significance at 3 and 6 months.Conclusion:Although statistical analysis was limited due to our population size and the retrospective nature of the study, there was an overall improvement in both radiographic parameters and clinical outcome scores. Older patients are also at higher risk of complications. Malrotation correction with this biplanar plating system is a novel technique and does require meticulous training. With continued expansion of our patient database and further longitudinal analysis, we hope to determine not only if correction is maintained over time, but also if the steepness of the learning curve affects the number of complications earlier versus later in each individual surgeon’s experience.

Three-Dimensional Weightbearing Assessment of the First Ray in Hallux Valgus: A Case-Control Study

Category:BunionIntroduction/Purpose:Coronal plane rotational deformity of the first ray has been implicated with the developmental pathologic process of hallux valgus (HV). Weight Bearing CT (WBCT) is an imaging technology that can support the assessment of this complex three-dimensional (3D) deformity. The objective of the study was to analyze the 3D architecture of the first ray in patients with HV when compared to controls using WBCT images and a 3D biometric algorithm analyzing the deformity in all three planes. We hypothesized that WBCT would confirm the rotational deformity in HV patients, and that the 3D algorithm would demonstrate increased specificity and sensitivity for the pathology when compared to traditional two-dimensional (2D) HV measurements such as the 1-2 intermetatarsal angle.Methods:Retrospective case-control study, ethics committee approved. Twenty-one feet of patients with clinically symptomatic HV and 20 feet of asymptomatic controls were included. Exclusion criteria applied were previous trauma or surgery affecting first ray or forefoot morphology. All patients were assessed using WBCT. First ray 3D coordinates (x, y, z) were harvested including: center-points of the heads and bases of the first and second metatarsals, center-point of the medial and lateral sesamoids, distal condyles of the proximal phalanx (PP) of the first toe, as well as the medial and lateral borders of the first metatarsal head and diaphysis. The 2D measurements (dorsoplantar 1-2 intermetatarsal (IMA) and metatarsophalangeal (MPA) angles) were obtained using digitally reconstructed radiographs (DRR). The Sesamoid Rotation Angle (SRA) was measured in the coronal plane. Using these coordinates, all 2D, 3D axes, distances, angulations and 3D biometric for HV (HV-3DB) could be calculated.Results:Mean ages were respectively 62.2y in the HV group and 48.8y in the control group (p<0.05). In 2D, the mean IMA and MPA for HV/controls were respectively 14.9/9.3 (p<0.001) and 30.1/13.1 (p<0.001). The SRA were respectively 29.1/7.1 (p<0.001). We found an almost perfect positive correlation between P1 rotation and sesamoid rotation, good correlation between IMA, MPA and SRA angles. There was poor correlation between pronation angles of the 1st phalanx and the 1st metatarsal. The 3D biometric algorithm combining IMA, MPA and SRA had a sensitivity of 95% and a specificity of 95.2% for the diagnosis of HV, compared to 90%/85.6% for the IMA and 90%/90.5% for the SRA.Conclusion:This original study confirmed our hypotheses. Weight Bearing CT efficiently analyzed the 3D architecture of the 1st ray in HV patients compared to asymptomatic controls. We concur with previous findings described in the literature concerning increased pronation of the 1st ray in HV. A novel biometric for HV using a specific multidimensional algorithm which combined IMA, HVA and SRA in a single 3D measurement, demonstrated increased sensitivity and specificity compared to the conventional 2D 1-2 intermetatarsal angle for the diagnosis of HV.

Defining the Zygomaticosphenoidal Angle as a Guide to Anatomic Zygomaticomaxillary Complex Fracture Reduction.

Alignment of the zygomaticosphenoid suture is fundamental to reduction of zygomaticomaxillary complex fractures. To prevent a rotational deformity, the correct angle of the zygoma relative to the cranial base must be restored. Clinically, this can be a challenge, especially when there is comminution of the zygomaticosphenoid suture. Defining a zygomaticosphenoidal angle would provide a reference for use with stereotactic navigation to achieve anatomic reduction. A single-center retrospective analysis of 100 patients was designed to determine normative zygomaticosphenoidal angle values. An angle subtended by the midline and a best-fit line through the zygomaticosphenoid suture on axial computed tomography was measured bilaterally in patients with isolated mandibular or nasal fractures. The mean of this measurement for 3 vertically adjacent cuts was calculated with position of central cut determined by the equator of the globe and trigone of the sphenoid. Multivariate regression was completed to identify changes in zygomaticosphenoidal angle with age, sex, and race. The mean zygomaticosphenoidal angle was 47° (range 39°-55°). 97% of angles were within 2 standard deviations (8°) of mean. Regression analysis demonstrated no significant change in angle with age (P = 0.74) or sex (P = 0.89). For each angle, the variation across the 3 sample cuts was ≤4.5°. Patients demonstrated high fidelity in zygomaticosphenoidal angle bilaterally with mean difference of 3°. The zygomaticosphenoidal angle is a useful reference, in conjunction with stereotactic navigation, for reduction of zygomaticomaxillary complex fractures. Contralaterally obtained patient-specific data may be used to guide unilateral repair. Normative values may serve as reference in bilateral injury.

Helical structure of actin stress fibers and its possible contribution to inducing their direction-selective disassembly upon cell shortening.

Mechanisms of the assembly of actin stress fibers (SFs) have been extensively studied, while those of the disassembly-particularly cell shortening-induced ones-remain unclear. Here, we show that SFs have helical structures composed of multi-subbundles, and they tend to be delaminated upon cell shortening. Specifically, we observed with atomic force microscopy delamination of helical SFs into their subbundles. We physically caught individual SFs using a pair of glass needles to observe rotational deformations during stretching as well as ATP-driven active contraction, suggesting that they deform in a manner reflecting their intrinsic helical structure. A minimal analytical model was then developed based on the Frenet-Serret formulas with force-strain measurement data to suggest that helical SFs can be delaminated into the constituent subbundles upon axial shortening. Given that SFs are large molecular clusters that bear cellular tension but must promptly disassemble upon loss of the tension, the resulting increase in their surface area due to the shortening-induced delamination may facilitate interaction with surrounding molecules to aid subsequent disintegration. Thus, our results suggest a new mechanism of the disassembly that occurs only in the specific SFs exposed to forced shortening.