Alignment Angle Research Articles

Predicting valgus malalignment after mobile-bearing UKA using a new method: the arithmetic HKA of the arthritic knee.

Valgus malalignment is one of the most common reasons for the progression of osteoarthritis in the lateral compartment of the knee after mobile-bearing unicompartmental knee arthroplasty (UKA). The arithmetic hip-knee-ankle angle (aHKA) of the Coronal Plane Alignment of the Knee (CPAK) classification could reflect the constitutional alignment of the arthritic knee. The purpose of this study was to observe the relationship between the aHKA and valgus malalignment after mobile-bearing UKA. This retrospective study was conducted using 200 knees undergoing UKA from January 1, 2019, to August 1, 2022. These radiographic signs, including preoperative hip-knee-ankle angle (HKA), mechanical proximal tibial angle (MPTA), mechanical lateral distal femoral angle (LDFA), and postoperative HKA, were measured using standardized weight-bearing long-leg radiographs. Patients with postoperative HKA > 180° and postoperative HKA ≤ 180° were classified as the valgus group and non-valgus group, respectively. The aHKA was calculated as 180° + MPTA - LDFA in this study, which had the same meaning as that (aHKA = MPTA - LDFA) in the CPAK classification. The Spearman correlation analysis, the Mann-Whitney U test, the chi-square test, the Fisher's exact test, and multiple logistic regression were used in the study. Of the 200 knees included in our study, 28 knees were classified as the valgus group, while 172 knees were in the non-valgus group. The mean ± standard deviation (SD) of aHKA (all groups) was 177.04 ± 2.58°. In the valgus group, 11 knees (39.3%) had a value of aHKA > 180°, while 17 knees (60.7%) had a value of aHKA ≤ 180°. In the non-valgus group, 12 knees (7.0%) had a value of aHKA > 180°, while 160 knees (93.0%) had a value of aHKA ≤ 180°. In Spearman correlation analysis, aHKA was positively correlated with postoperative HKA (r = 0.693, p < 0.001). In univariate analysis, preoperative HKA (p < 0.001), LDFA (p = 0.02), MPTA (p < 0.001), and aHKA (p < 0.001) showed significant differences between the valgus and non-valgus groups. Variables with p < 0.1 in univariate analysis were further analyzed using multiple logistic regression analysis, and the variable-aHKA (> 180° vs ≤ 180°, odds ratio (OR) = 5.899, 95% confidence interval (CI) = 1.213 to 28.686, and p = 0.028) was expressed as the risk factor of postoperative valgus malalignment. The aHKA is correlated with the postoperative alignment of mobile-bearing UKA and a high aHKA (> 180°) will increase the risk of postoperative valgus malalignment. Therefore, mobile-bearing UKA should be performed with caution in patients with preoperative aHKA > 180°.

Pedicle screw augmentation in posterior constructs of the thoracolumbar spine: How many pedicle screws should be augmented?

BackgroundsTo evaluate the effects of different pedicle screw augmentation strategies on screw loosening and adjacent segment collapse at the proximal end of long-segment instrumentation. MethodsEighteen osteoporotic (9 male, 9 female donors; mean age: 74.7 ± 10.9 [SD] years) thoracolumbar multi-segmental motion segments (Th11 – L1) were assigned as follows: control, one-level augmented screws (marginally), and two-level augmented screws (fully augmented) groups (3 × 6). Pedicle screw placement was performed in Th12 and L1. Cyclic loading in flexion started with 100–500 N (4 Hz) and was increased by 5 N every 500 cycles. Standardized lateral fluoroscopy images with 7.5 Nm loading were obtained periodically during loading. The global alignment angle was measured to evaluate the overall alignment and proximal junctional kyphosis. The intra-instrumental angle was used to evaluate screw fixation. FindingsConsidering screw fixation as a failure criterion, the failure loads of the control (683 N), and marginally (858 N) and fully augmented (1050 N) constructs were significantly different (ANOVA p = 0.032).Taking the overall specimen alignment as failure criteria, failure loads of the three groups (control 933 ± 271.4 N, marginally 858 N ± 196 N, and full 933 ± 246.3 N were in the same range and did not show any significance (p = 0.825). InterpretationGlobal failure loads were comparable among the three groups and unchanged with augmentation because the adjacent segment and not the instrumentation failed first. Augmentation of all screws showed significant improved in screw anchorage.

Outcomes of Combined Posterior Tibial Tendon Tendoscopy and Medializing Calcaneal Osteotomy for Stage IA Progressive Collapsing Foot Deformity.

Posterior tibial tendon (PTT) tendoscopy and medializing calcaneal osteotomy (MCO) are among the available techniques for patients presenting with symptomatic flexible hindfoot valgus (stage IA) progressive collapsing foot deformity (PCFD). The aim of this study was to determine clinical and radiographic outcomes of combined PTT tendoscopy and MCO for patients presenting with symptomatic stage IA PCFD. A retrospective cohort study was performed in order to determine clinical and radiographic outcomes of 30 combined PTT tendoscopies and MCO on 27 patients presenting with symptomatic stage IA PCFD, with a minimum follow-up of 24 months. Patient satisfaction was assessed at last available follow-up as very satisfied, satisfied, and unsatisfied. Clinical assessment was performed evaluating preoperative and last available follow-up visual analog scale for pain (VAS-P), Foot and Ankle Outcome Score (FAOS), and the 36-Item Short Form Health Survey (SF-36). Magnetic resonance imaging (MRI) was performed preoperatively on all patients. Standard weightbearing anteroposterior, lateral, and long axial view radiographs of the foot and ankle were taken preoperatively, immediate postoperatively, at 6 weeks, 3 months, 6 months, 1 year postoperatively, and last follow-up evaluation available for each patient. The mean follow-up was 38.6 (range, 26-62) months. We registered 27 very satisfied, 1 satisfied, and 2 unsatisfied patients. There was statistically significant improvement on all clinical scores (VAS-P, FAOS and SF-36), as well as on lateral talo-first metatarsal and hindfoot alignment angles. We found low-grade PTT tears in 5 patients (16.67%) in whom preoperative MRI documented PTT tenosynovitis alone. We found that combined PTT tendoscopy and MCO provide significant clinical and radiographic improvement for patients presenting with symptomatic stage IAB PCFD. PTT tendoscopy should be considered in the treatment of all surgically addressed flexible valgus feet as it detects tendon tears which are frequently missed on an MRI. Level IV, retrospective case series.

Subchondral insufficiency fracture is a predictive factor of osteoarthritis progression and conversion to arthroplasty in non-surgically treated medial meniscus root tear.

To investigate the radiographic and clinical outcomes of non-surgical treatment for medial meniscus posterior root tear (MMPRT), and prognostic factors for osteoarthritis (OA) progression and clinical failure. A prospectively collected database was retrospectively reviewed for patients who were diagnosed with acute medial meniscus posterior root tear (MMPRT) between 2013 and 2021 and treated non-surgically for more than 2years. Patient demographic characteristics and clinical outcomes including pain numeric rating scale (NRS), International Knee Documentation Committee (IKDC) subjective score, Lysholm score, and Tegner activity scale were evaluated. For radiographic evaluation, knee radiographs were obtained to assess the angle of knee alignment and Kellgren-Lawrence (K-L) grade during the first and annually follow-up visits. Baseline magnetic resonance (MR) images were reviewed for the presence of medial meniscus extrusion, bone marrow edema, subchondral insufficiency fracture of medial femoral condyle, and cartilage lesion. The OA progression group was defined as patients who experienced a worsening of one or more grades in the K-L classification system. Prognostic factors were evaluated for OA progression and conversion to total knee arthroplasty (TKA). Ninety-four patients (90 female and 4 male) with a mean age of 67.0 ± 7.3years (range, 53-83years) were followed for a mean of 46.1 ± 22.1months (range, 24.1-170.5). During the follow-up period, no significant differences in clinical scores were observed, and there were also no significant differences between the groups with and without OA progression. Overall, 12 patients (13%) underwent TKA at a mean of 20.7 ± 16.5months (range, 8-69months) and 34 patients (36%) demonstrated OA progression at a mean time of 24 ± 15months (range, 12-62). The subchondral insufficiency fracture was a prognostic factor for OA progression (p = 0.045 for knee radiograph and p = 0.019 for MR) and conversion to TKA (RR, 4.08 [95% CI 1.23-13.57]; p = 0.022). Non-surgical treatment for acute medial meniscus posterior root tear did not result in any significant change in clinical outcomes from the initial to the final follow-up. The rate of conversion to arthroplasty was 13%, and the rate of osteoarthritis progression was 36%. Furthermore, subchondral insufficiency fracture was found to be a concomitant prognostic factor correlated with OA progression and conversion to arthroplasty. This information can provide insights for physicians when discussing treatment options with patients, particularly regarding the use of non-surgical treatment and may contribute as a source for future studies of medial meniscus posterior root tear. IV.

Mechanical behavior of monolayer MoS2 films with arrayed dislocation defects

Compared with single and randomly distributed defects, arrayed defects exist widely in the film structure and can be designed artificially to achieve various specific functions. However, the mechanical behavior of transition metal dihalides with dislocation array defects is unclear; this limits their application in new flexible nanodevices. In this study, the strength and fracture properties of monolayer MoS2 films containing 5|7 (S5|7 and Mo5|7) dislocation defects under uniaxial tension were studied by molecular dynamics simulation. The results show that the number of defects, adjacent spacing, and alignment angle affect the critical strain and tensile strength of the monolayer MoS2 films. These results provide a basis for further understanding the mechanical behavior of monolayer MoS2 thin films and provide a theoretical reference for the application of nano-electronic devices based on MoS2.

Improved fibre placement in filament-based 3D printing of continuous carbon fibre reinforced thermoplastic composites

This study investigates the mechanism of fibre deposition in conventional 3D printing and presents an aligned fibre deposition (AFD) method to improve the fibre placement. The deposition mechanism reveals that the cracking of the filament in the transition zone and the torsional deformation during the steering path are the main cause of the defects in the conventional printing process. The AFD method is shown to reduce and mitigate the fibre waviness and twisting, hence producing smooth filament deformation, introducing less air voids and fibre breakage during printing. It is found that the AFD method improves the fibre alignment angle from ±25° to ±12° and reduces the void content to 0.27 % during straight-line deposition. During curved-line printing at a large radius of curvature, tow shearing instead of fibre folding is produced by AFD method, resulting in smooth edges with less fibre breakage.

Hip abduction angle after open-wedge high tibial osteotomy is associated with the timed up & go test and recurrence of varus alignment

The aim of this study is to investigate the association between the hip abduction angle (HAA) and lower limb alignment as well as the clinical assessments in open-wedge high tibial osteotomy (OWHTO) patients. A total of 90 patients who underwent OWHTO were included. The demographic characteristics and clinical assessments (the Visual Analogue Scale for activities of daily living, the Japanese knee osteoarthritis measure, the Knee injury and Osteoarthritis Outcome Score, the Knee Society score, the Timed Up & Go (TUG) test, the single standing (SLS) test and muscle strength) were recorded. The patients were divided into two groups according to the HAA at 1 month after operation: the HAA (−) group (HAA < 0°) and the HAA (+) group (HAA ≥ 0°). Clinical scores except for the SLS test and radiographic parameters except for the posterior tibia slope (PTS), lateral distal femoral angle (LDFA) and lateral distal tibial angle (LDTA) were significantly improved at 2 years postoperatively. Regarding the two groups, scores on the TUG test in the HAA (−) group were significantly lower than those in the HAA (+) group (p = 0.011). The hip-knee-ankle angle (HKA), weight bearing line (WBLR) and knee joint line obliquity (KJLO) in the HAA (−) group were significantly higher than those in the HAA (+) group (p < 0.001, 0.001 and p = 0.025). In contrast, the LDFA in the HAA (−) group were significantly lower than those in the HAA (+) group (p < 0.001). The TUG test and the LDFA were weakly positively correlated with the HAA (r = 0.34, 0.42, p < 0.001 and 0.001). In contrast, the HKA, WBLR and KJLO had a weak negative correlation with the HAA (r = − 0.43, − 0.38 and − 0.37, p < 0.001, 0.001 and 0.001). This study showed the postoperative HAA was significantly associated with the TUG test and the HKA, WBLR, LDFA, and KJLO. A higher postoperative HAA might induce varus recurrence and poor outcomes of the gait parameter.

Wind effect on scallop domes with negative amplitude and prominence using Experimental and Numerical Study

This study investigates the wind effect on hexa-sectored scallop domes using Computational Fluid Dynamics (CFD) and wind tunnel tests. Similar to the shape of a seashell, the scallop dome is one of the most common domes used to cover large spans. The scallop dome has an additional curvature equal to its sectors compared to a base dome (spherical). Hence, it has better structural efficiency compared to a spherical dome under the same condition. The curvatures on the scallop dome create alternate “ridges” and “grooves” on it. According to the computations of the article, the grooves created on this dome in the sector, as well as their position angle to the wind direction significantly affect pressure coefficient value. Due to these differences, wind pressure on scallop domes significantly differs from wind pressure on spherical domes. The results indicate that the ridges cause negative wind pressure coefficients whose magnitude reaches a maximum of −2.0 for an angle of alignment of 30°. The analyses have been conducted through Ansys-Fluent. This study presents the equation of wind pressure coefficient in the most critical of dome groove positions. The arch created between the grooves of a scallop dome is another effective parameter on maximum negative pressure. In the case study scallop dome, if the wind effect angle is considered α = 15, the maximum deformation in the structure will be created, which is 20% higher than that of α = 0.

High-order harmonic generation from aligned HCN molecules under orthogonally and linearly polarized two-color laser fields

Molecular high-order harmonic generation and molecular orbital ionization probabilities are calculated under orthogonally and linearly polarized two-color laser fields. When a second-harmonic field is applied, the high-order harmonics generated under the linearly polarized two-color laser fields in the antiparallel case are stronger than those generated in the orthogonal polarization case and even stronger than those of the parallel polarization case. The results show that ionization probabilities of various orbitals and harmonic orders are dependent on spatial symmetry of molecular orbitals. It is found that the ionization of low-lying Kohn-Sham molecular orbitals contributes significantly to the ionization and molecular high-order harmonic generation processes. The ionization probability maximum occurs when molecular orbital densities are maximum in the direction of laser field polarization. Furthermore, we show that the degeneracy of π orbitals is broken when the laser-molecule alignment angle deviates from the field axis. Accordingly, we indicated one component of the π orbital is effectively contributed to the ionization and high-order harmonic generation processes. Finally, to confirm the recollision model in the high-order harmonic generation, the quantum time-frequency analysis is used to extract electron paths information on subcycle time scales.

Alignment and Fixation in Revision Total Knee Arthroplasty With Press-Fit, Offset, Diaphyseal-Engaging Stem Extensions, and Eccentric Reaming Technique

BackgroundA revision total knee arthroplasty must control limb alignment, often to address the cause of failure. Press-fit stems that engage the diaphysis with cement restricted to the metaphysis constitute one fixation technique. These long stems restrict coronal alignment of the prosthesis and as a result reduce the likelihood of extreme malposition. For the same reasons, long stems can make it difficult to manipulate alignment and achieve a specific coronal alignment angle. Nevertheless, femoral stems with a tight diaphyseal fit may still occupy a small range of varus-valgus positions due to the conical distal femoral metaphysis. Pulling the reamer toward the lateral endosteum increases femoral component coronal alignment toward a valgus direction and pushing the reamer medially increases alignment in a more varus direction. A straight stem, in combination with a medially directed reaming, would result in a femoral component that overhangs medially, but an offset stem can recenter the femoral component and maintain the desired alignment. We hypothesized that diaphyseal fit plus this reaming technique can control limb coronal alignment and provide fixation. MethodsThis was a retrospective clinical and long-leg radiographic study of consecutive revision total knee arthroplasties with minimum 2-year follow-up. Outcomes were correlated with New Zealand Joint Registry data to identify rerevisions of 111 consecutive revision knee arthroplasties, 92 after exclusions, at a minimum 2-year (range, 2 to 10) follow-up. ResultsMean femoral and tibial canal fill exceeded 91% on antero-posterior and lateral radiographs. The mean hip-knee-ankle angle was 179.6o (174.9-184.0) with 80% within ± 3o of neutral. The hip-ankle axis crossed the central Kennedy zone in 76.5% of cases and the other 24.6% crossed the inner medial and inner lateral zones. Tibial components: 99.0% ± 3o. Femoral components: 89.5% within ± 3o. There were 5 knees that failed due to infection, 3 from femoral loosening, and 1 due to recurvatum instability from polio. ConclusionsThis study describes a surgical plan and technique for achieving target coronal alignment with press-fit diaphyseal fixation. It is the only series of revision knee arthroplasties with diaphyseal press-fit stems to report canal fill in 2 planes and coronal alignment on full-length radiographs.

Sport and Exercise Activity After Isolated Ankle Arthrodesis for Advanced-Stage Ankle Osteoarthritis: A Single-Center Retrospective Analysis.

Ankle arthrodesis, a recognized operative treatment for advanced-stage ankle osteoarthritis (OA), is recommended when conservative treatment proves unsuccessful. This single-center retrospective analysis examined the change in functional outcomes and the type of sport/exercise activity performed by advanced-stage ankle OA patients after ankle arthrodesis treatment. A total of 61 advanced-stage ankle OA patients (age, 63.1 ± 12.6 years) who had undergone ankle arthrodesis were included in this single-center retrospective study. The patients had functional outcomes evaluated via American Orthopaedic Foot & Ankle Society Score (AOFAS), Foot Function Index (FFI), Tegner Activity Level Scale (TAS), and High-Activity Arthroplasty Score (HAAS) questionnaires. Clinical status was compared across prearthritic, arthritic, and postarthrodesis periods, and satisfaction with return to sport/exercise activity was recorded. Patients' tarsal sagittal ROM (mean [95% CI]: 22.7 degrees [21.4-24.0]); time to union (15.7 weeks [11.8-19.6]); time to walk without gait aid (14.4 weeks [11.0-17.7]); time to return to work (17.9 weeks [15.1-20.8]); and time to exercise activity (20.6 weeks [17.9-23.4]) were recorded postarthrodesis. Hindfoot alignment angle toward a neutral position (difference: 11.4 degrees [9.2-13.6], P < .001) and functional outcomes (P < .001) significantly improved after arthrodesis surgery; however, only the TAS questionnaire indicated patients returned to their prearthritic activity level (P > .99). Patients generally reported "good" satisfaction with their recovery from ankle arthrodesis surgery, with 64% of patients returning to high-impact-type activity. Advanced-stage ankle OA patients had improved functional outcomes at ~1 year postarthrodesis surgery, enabling the majority of patients to return to high-impact-type activity. Level III, retrospective cohort study.

Mechanical alignment tolerance of a cruciate-retaining knee prosthesis under gait loading-A finite element analysis.

Component alignment is one of the most crucial factors affecting total knee arthroplasty's clinical outcome and survival. This study aimed to investigate how coronal, sagittal, and transverse malalignment affects the mechanical behavior of the tibial insert and to determine a suitable alignment tolerance on the coronal, sagittal, and transverse planes. A finite element model of a cruciate-retaining knee prosthesis was assembled with different joint alignments (-10°, -7°, -5°, -3°, 0°, 3°, 5°, 7°, 10°) to assess the effect of malalignment under gait loading. The results showed that varus or valgus, extension, internal rotation, and excessive external rotation malalignments increased the maximum Von Mises stress and contact pressure on the tibial insert. The mechanical alignment tolerance of the studied prosthesis on the coronal, sagittal, and transverse planes was 3° varus to 3° valgus, 0°-10° flexion, and 0°-5° external rotation, respectively. This study suggests that each prosthesis should include a tolerance range for the joint alignment angle on the three planes, which may be used during surgical planning.

Comparison of the effect of total knee arthroplasty and high tibial osteotomy on coronal pelvic and ankle–hindfoot alignment

BackgroundTotal knee arthroplasty (TKA) and high tibial osteotomy (HTO) are different procedures on the continuous spectrum of osteoarthritic knee treatments. TKA aims for neutral alignment and HTO aims for slight valgus. Methods2:2:2:1 propensity score matching yielded 100, 100, 100, and 50 patients with unilateral TKA, bilateral TKA, unilateral HTO, and bilateral HTO, respectively. Radiological evaluations of pelvis, knee, ankle, and hindfoot were performed. The important factors affecting the alignment change of the adjacent joints were identified, and subgroup analyses were performed using the identified parameters. The clinical outcomes were also compared. ResultsThe coronal alignments of the adjacent joints were corrected to the neutral position after TKA and HTO. The tibiotalar tilt angle (TTTA) was a common factor that affected changes in the ankle and hindfoot alignment. Patients with larger preoperative TTTA showed larger changes in TTTA in both TKA and HTO groups (P < 0.001). Patients with larger preoperative hindfoot alignment angle (HAA) showed larger changes in tibial plafond inclination, talar inclination, and HAA in both TKA and HTO groups (P < 0.001). TKA groups showed negative pelvic tilt values in the horizontal plane, and HTO groups showed a larger weight-bearing line ratio. ConclusionEven more severe deformities including adjacent joints were observed in TKA patients, both TKA and HTO patients showed improved alignment of the adjacent joints. However, HTO patients showed closer normal alignment than patients who underwent TKA. The preoperative TTTA and HAA were important factors for restoration of ankle and hindfoot alignment after knee surgery.

Simulated Weightbearing Fluoroscopy to Assess Intraoperative Hindfoot Alignment.

Intraoperative evaluation of hindfoot alignment is one of the factors that may affect outcomes for foot and ankle reconstructive surgery. The present study was performed to evaluate the effect of simulated weightbearing fluoroscopy on the intraoperative assessment of hindfoot alignment reconstruction. The medical records of patients diagnosed with disorders of the foot and ankle with abnormal hindfoot alignment were retrospectively reviewed from November 2014 to November 2021. Hindfoot alignment view (HAV) fluoroscopy in the simulated weightbearing position and HAV radiographs were routinely recorded during and after surgery, respectively. The hindfoot alignment angle (HAA) and hindfoot alignment ratio (HAR) were measured on intraoperative and postoperative images, respectively. Seventy-two women and 82 men (155 ankles) with a mean age of 45.48 years were included in the present study. The intraobserver and interobserver reliabilities of the HAA and HAR measurements were satisfactory. The intraoperative and postoperative HAA was -0.7 ± 4.8 degrees and -0.2 ± 5.0 degrees, respectively. The mean HAR on intraoperative fluoroscopy and postoperative radiographs was 37.4% ± 19.7% and 40.4% ± 18.2%, respectively. Simple regression analysis revealed a correlation between the intraoperative and postoperative HAA (R2 = 0.631, P < .001) and HAR (R2 = 0.262, P < .001). Univariate analysis suggested that the difference between the intraoperative and postoperative HAA was positively affected by the body mass index (P < .001). The present study showed that intraoperative HAV fluoroscopy in the simulated weightbearing position is a potentially useful method to predict postoperative hindfoot alignment in the weightbearing position. Patients with a lower body mass index had smaller HAA deviations between intraoperative and postoperative measurements of hindfoot alignment. Level IV, retrospective case series.

Calcaneal V-shaped osteotomy combined with subtalar arthrodesis for Stephens Ⅱ and Ⅲ calcaneal fractures malunion

To investigate the effectiveness of calcaneal V-shaped osteotomy combined with subtalar arthrodesis in the treatment of Stephens Ⅱand Ⅲ calcaneal fracture malunion. The clinical data of 24 patients with severe calcaneal fracture malunion treated by calcaneal V-shaped osteotomy combined with subtalar arthrodesis between January 2017 and December 2021 were retrospectively analyzed. There were 20 males and 4 females with an average age of 42.8 years (range, 33-60 years). Conservative treatment of calcaneal fracture failed in 19 cases and operation failed in 5 cases. Stephens classification of calcaneal fracture malunion was type Ⅱ in 14 cases, and type Ⅲ in 10 cases. Preoperative Böhler angle of calcaneus was 4.0°-13.5° (mean, 8.6°), Gissane angle was 100°-152° (mean, 119.3°). The time from injury to operation was 6-14 months (mean, 9.7 months). American Orthopedic Foot and Ankle Society (AOFAS) ankle and hindfoot score and visual analogue scale (VAS) score were used to evaluate the effectiveness before operation and at last follow-up. Bone healing was observed and the healing time was recorded. The talocalcaneal height, talus inclination angle, Pitch angle, calcaneal width, and hindfoot alignment angle were measured. Necrosis of the cuticle edge of the incision occurred in 3 cases, which were cured by dressing change and oral administration of antibiotic therapy. The other incisions healed by first intention. All the 24 patients were followed up 12-23 months, with an average of 17.1 months. The foot shape of the patients recovered well, the shoes were restored to the size before injury, and there was no anterior ankle impingement. Bone union was achieved in all patients, and the healing time ranged from 12 to 18 weeks, with an average of 14.1 weeks. At last follow-up, no adjacent joint degeneration occurred in all patients; 5 patients had mild foot pain during walking, which had no significant impact on daily life and work; no patient needed revision surgery. The AOFAS ankle and hindfoot score was significantly higher than that before operation ( P<0.001), the results were excellent in 16 cases, good in 4 cases, and poor in 4 cases, and the excellent and good rate was 83.3%. The VAS score, talocalcaneal height, talus inclination angle, Pitch angle, calcaneal width, and hindfoot alignment angle were significantly improved after operation ( P<0.001). Calcaneal V-shaped osteotomy combined with subtalar arthrodesis can effectively relieve hindfoot pain, correct talocalcaneal height, restore talus inclination angle, and reduce the risk of nonunion after subtalar arthrodesis.

Iterative projection algorithm for retrieval of angle-resolved single-molecule dipoles from high-harmonic spectra

High-order harmonic spectroscopy (HHS), as an emerging technique, provides a way to detect molecular structures with \aa{}ngstr\"om spatial resolution and ultrafast electron dynamics in molecules on an attosecond timescale. However, the implementation of HHS still encounters great difficulties due to the coherent average of single-molecule emissions from different alignment angles. Here, we provide a machine learning algorithm based on the iterative projection method to fully retrieve the complex single-molecule dipole of a linear molecule from the harmonic spectra measured at different delays and polarization angles between the alignment and driving pulses. We demonstrated our algorithm both theoretically and experimentally using the ${\mathrm{N}}_{2}$ molecule. The results show that our algorithm can accurately retrieve the complex single-molecule dipole from the harmonic spectra with good noise stability and robustness. From the retrieved single-molecule dipole, the contributions of multiple orbitals in high harmonic generation are identified even with a low degree of alignment.

Thoracolumbar curve behavior after selective thoracic anterior vertebral body tethering in Lenke 1A vs Lenke 1C curve patterns.

Retrospective review of a prospective database. The purpose of this study is to evaluate changes in the thoracic and thoracolumbar/lumbar curves and truncal balance in patients treated with selective thoracic anterior vertebral body tethering (AVBT) with Lenke 1A vs 1C curves at a minimum of 2 years follow-up. Lenke 1C curves treated with selective thoracic AVBT demonstrate equivalent thoracic curve correction and reduced thoracolumbar/lumbar curve correction compared to Lenke 1A curves. Additionally, at the most recent follow-up, both curve types demonstrate comparable coronal alignment at C7 and the lumbar curve apex, though 1C curves have better alignment at the lowest instrumented vertebra (LIV). Rates of revision surgery are equivalent between the two groups. A matched cohort of 43 Risser 0-1, Sanders Maturity Scale (SMS) 2-5 AIS pts with Lenke 1A (1A group)and 19 pts with Lenke 1C curves (1C group) treated with selective thoracic AVBT and a minimum of 2-year follow-up were included. Digital radiographic software was used to assess Cobb angle and coronal alignment on preoperative, postoperative and subsequent follow-up radiographs. Coronal alignment was assessed by measuring the distance from the center sacral vertical line (CSVL) to the midpoint of the LIV, apical vertebra for thoracic and lumbar curves and C7. There was no difference in the thoracic curve measured preoperatively, at first erect, pre-rupture or at the most recent follow-up, nor was there a significant difference in C7 alignment (p = 0.057) or apical thoracic alignment (p = 0.272) between the 1A and 1C groups. Thoracolumbar/lumbar curves were smaller in the 1A group at all-time points. However, there was no significant difference between the percent correction between the two groups thoracic (p = 0.453) and thoracolumbar/lumbar (p = 0.105). The Lenke 1C curves had improved coronal translational alignment of the LIV at the most recent follow-up p = 0.0355. At the most recent follow-up the number of patients considered to have successful curve correction (Cobb angle correction of both the thoracic and thoracolumbar//lumbar curves to ≤ 35 degrees), was equivalent between Lenke 1A and Lenke 1C curves (p = 0.80). There was also no difference in the rate of revision surgery between the two groups (p = 0.546). This is the first study to compare the impact of lumbar curve modifier type on outcomes in thoracic AVBT. We found that Lenke 1C curves treated with selective thoracic AVBT demonstrate less absolute correction of the thoracolumbar/lumbar curve at all time points but have equivalent percent correction of the thoracic and thoracolumbar/lumbar curves. The two groups have equivalent alignment at C7 and the thoracic curve apex, and Lenke 1C curves have better alignment at the LIV at the most recent follow-up. Furthermore, they have an equivalent rate of revision surgery compared to Lenke 1A curves. Selective thoracic AVBT is a viable option for selective Lenke 1C curves, but despite equivalent correction of the thoracic curve, there is less correction of the thoracolumbar/lumbar curve at all-time points.

Surgical Outcomes with and without Prism Adaptation of Cases with Acute Acquired Comitant Esotropia Related to Prolonged Digital Device Use.

To analyze surgical results of 32 cases with acute acquired comitant esotropia (AACE) related to prolonged use of digital devices (DDs). Medical records of cases with AACE related to prolonged use of DDs that had undergone surgery were retrospectively revised. Complete medical history and full ophthalmological examinations before and surgery were obtained for all cases. All cases also underwent neurological examinations using brain and orbital imaging. Motor success was considered as alignment within 10 prism diopters (Δ) at both near and distance. Sensory success was defined as stereopsis ≤60 arcsec. Nineteen cases (Group S) underwent surgery alone and 13 cases were treated with surgery and prism adaptation (Group S+P). Motor and sensory outcomes were compared between groups. Mean age at first visit was 22.0 ± 9.0 years and mean daily use of DDs use was 6.3 ± 3.4 hours. Mean angle of preoperative alignment for distance and near were 26.5 ± 13.0Δ and 24.6 ± 16.4Δ, respectively. Surgery was performed at a mean of 23.3 ±3.5 years old and mean angle of alignment at final examination for distance and near were 5.8 ± 7.7Δ and 3.5 ± 5.7Δ, respectively. Final motor and sensory success rate were 84% and 53%, respectively. No significant differences in motor or sensory outcomes were evident between groups at initial or last visit. Favorable motor and sensory outcomes were achieved with surgical intervention with and without prism adaptation for AACT related to prolonged use of DDs.

Alignment sensitivity of molecular-frame photoelectron momentum and angular distribution of by XUV attosecond pulses

In this work, we investigate the molecular-frame photoelectron momentum and angular distributions (MF-PMD and MF-PAD) of in the presence of XUV Attosecond Pulses. We present the alignment-sensitive effect of MF-PMDs and MF-PADs when the laser field polarization and the molecular axis are close to parallel geometry. Our results show that the MF-PADs and MF-PMDs of single-photon ionization of ion vary drastically when the alignment slightly shifts from parallel geometry to a small alignment angle (e.g. 4°) between the laser polarization direction and the molecular axis at the equilibrium inter-nuclear distance of R c = 2 atomic units. As R c increases to 4 atomic units, such sensitivity is decreased. The R c -dependent transition cross-sections in different channels are found to be the origin of such sensitivity.

Kinematics analysis of tennis forehand strokes in different directions for the elite female college tennis players

&lt;p&gt;目的：探討優秀大專女子網球選手執行正拍直線球、對角球與閃正拍外角球之動作分期時間、軀幹旋轉特徵與擊球位置之動作技術差異。方法：以 9 名台灣大專甲組之女子網球選手為研究對象，透過 Motion 動作分析系統與十台紅外線高速攝影機 (取樣頻率為 200 Hz) 記錄網球正拍擊球執行直線球、對角球、閃正拍外角球之動作技術，以相依樣本單因子變異數分析進行統計分析。結果：在擊球動作期別上僅在加速期達顯著差異且對角球大於閃正拍球；軀幹與站姿軸的運動學參數中，除了肩軸沒有達顯著差異外，球拍長軸與底線夾角、髖軸、站姿軸設定皆達顯著差異；此外，擊球點與肩膀的前後距離以及髖部的前後、左右距離的相對位置皆達顯著差異。結論：當球員針對不同方向擊球時，球拍開始向前加速的加速期是影響方向的關鍵時期。在擊球瞬間肩部旋轉並不是影響擊球方向的主要因子，且選手在執行閃正拍外角擊球會採取較大幅度的軀幹旋轉策略進行調節。此外，擊球點與身體的相對位置關係，不論肩部或是髖部的前後距離是影響擊球方向的關鍵因素，在左右側的擊球點位置閃正拍相較於直線與對角球會更靠近軀幹。本研究結果希望讓教練與選手了解，在執行不同擊球方向或閃正拍外角球策略時，身體軀幹特徵之異同，且可以作為球員在比賽中預判對手擊球策略時的參考因素之一。&lt;/p&gt; &lt;p&gt;&amp;nbsp;&lt;/p&gt;&lt;p&gt;Purpose: This study identified and compared the kinematic difference of each phase, trunk, and stance when balls were hit cross-court, down-the-line, and inside-out forehand for the elite college female tennis players. Methods: Nine female tennis players from Taiwan college Division 1 players were recorded using a ten-cameras with motion analysis system (200 Hz). The techniques of hit down-the-line, cross-court, and inside-out forehand were recorded, and statistically analyzed by one-way ANOVA with repeated measured. Results: The only significant difference was found in the acceleration phase and the cross-court was larger than inside-out forehand. For the kinematic parameters, the angle of the long axis of the racket, hip alignment, stance alignment were statistically different. In addition, in the relative positions of the contact point, there was no significant difference in vertical height on shoulder and hip, and the shoulder was only significant in the hitting direction, but the hip was significantly different in the hitting direction and the side direction. Conclusion: In the situation of different directions, the acceleration phase when the racket starts to accelerate forward, is the key phase that affects the direction. At impact, shoulder alignment angle is not the main factor affecting the direction of the shot. The players will adopt more trunk rotation when performing inside-out forehand shots. In addition, the relative position of ball impact, the distance between the contact point with shoulder and hip on the front direction is the key factor. On the side direction, the inside-out forehand is closer to the trunk than the cross-court and down-the-line shots. This study provides coaches and players with strategies of different directions and inside-out forehand. The body characteristics can be a reference for players to predict the opponent’s strategy in the matches.&lt;/p&gt; &lt;p&gt;&amp;nbsp;&lt;/p&gt;