Declination Angle Research Articles

An analysis of radiologic and anatomical parameters associated with medial osteochondral lesions of the talus in non-traumatic cases

The study aimed to provide a comprehensive analysis of radiological and anatomical measurements in patients with medial osteochondral lesions of the talus (OLT), particularly those without a history of trauma. The retrospective cross sectional study evaluated 23 medial OLT individuals aged 18–45 with no history of trauma who were identified by magnetic resonance imaging (MRI) between 2016 and 2020. The control group consisted of 27 individuals between the ages of 18 and 45 who did not have OLT and applied for other reasons. Measurements were performed with 16 parameters from anteroposterior (AP) and lateral weight-bearing ankle conventional radiographs (CR). All individuals' demographic data were assessed. A total of 50 patients aged 18–45 years, including 26 males and 24 females with a mean age of 30.28±4.46 years, were evaluated in the study. No significant differences in age or gender were found between the groups (P>0.05). Analysis of both the OLT and control groups revealed a significant association of decreased talar declination angle (P<0.001) and Meary-Tomeno's angle (P = 0.003) with medial OLT. There was no relationship between other radiological parameters and medial OLT development. In conclusion, a decreased talar declination angle and a decreased Meary-Tomeno's angle appear to have significant relationship with development of medial OLT in individuals without a history of trauma. These findings also indicate that a possible cause of medial OLT is a lower-angled positioning of the talus relative to the ground and the first metatarsus in the sagittal plane.Level of Clinical Evidence: Level 3 cross sectional study

Outcomes of cobalt-chrome 3D-printed total talus replacement with and without combined total ankle replacement

BackgroundCollapse of the talus and peri-talar arthritis pose treatment challenges due to the anatomy and location of the talus as a keystone of the foot and ankle. Custom 3D-printed total talus replacement (TTR) and combined total ankle total talus replacement (TATTR) have emerged as treatment options for these pathologies. However, the safety and efficacy of these implants is unknown due to the limited number of cases and short follow-up durations. MethodsThis was a retrospective study to assess surgical outcomes of patients who underwent a TTR and TATTR with or without subtalar fusion. Patient demographics, intraoperative parameters, device related surgical and non-surgical events, imaging and clinical evaluations, and patient reported outcome (PRO) measures were compiled. ResultsA total of 38 patients received a custom 3D-printed implant with mean follow-up time of 22.1 (range: 12–45) months. In this cohort, 7 (18.4 %) required secondary surgery and 3 (7.9 %) required implant removal. Multivariate logistic regression revealed that patient diagnosis of depression was a significant predictor of secondary surgery with an OR 17.50 (p = 0.037). Significant postoperative improvements were observed in the talocalcaneal height (p = 0.005) and talar declination angle (p = 0.013) for the TATTR group. VAS and PROMIS pain interference (PI) scores demonstrated an initial significant improvement in pain, but this improvement did not maintain significance at most recent follow-up. However, there was a significant increase in the PROMIS physical function (PF) scores (p = 0.037) at most recent follow-up. ConclusionThese results demonstrate that TTR and TATTR provide significant improvement in post-operative radiographic foot and ankle alignment and physical function at the two-year timepoint. PRO findings suggest that patients are more active after surgery. Surgeons considering proceeding with either of these procedures should counsel patients about pain and functional outcomes as well as realistic expectations in patients with depression. Level of evidenceLevel 3

Statistical analysis of low latitude spread F at the American, Atlantic, and Pacific sectors using digisonde observations

Statistical analysis of low latitude spread F is presented for three different longitudinal sectors from Jicamarca (12°S, 76.8°W, −2.5° declination angle) from 2001 to 2016, Ascension Island (7.9°S, 14.4°W, −15.09° declination angle) from 2000 to 2014, Kwajalein (8.71°N, 167.7°E, 7.5° declination angle) from 2004 to 2012. Digisonde data from these stations have been processed and analyzed to study statistical variations of equatorial spread F, a diagnostic of irregular plasma structure in the ionosphere. A new automated method of spread F detection using pattern recognition and edge detection for low latitude regions is used to determine solar and seasonal variation over these three sites. An algorithm has been developed to detect the foF2 and hpF2 parameters and this has been validated by comparisons with manually scaled data as well as with SAMI2 and International Reference Ionosphere models showing good correlation. While significant variation is not observed over the solar cycle, the different longitudes and declination angles contribute to the variations over the seasonal cycle.

A measurement method for magnetic moment and magnetic declination of ferromagnetic samples based on rotating magnetic dipole

Abstract This paper presents a novel measurement method for detecting the magnetic properties of ferromagnetic materials. The proposed method uses a motor to rotate the ferromagnetic sample. At the same time, a triaxial magnetometer reads the magnetic field information, and the motor rotation frequency and the magnetometer sampling rate obtain the rotation angle information. A nonlinear optimization algorithm is applied to calculate the magnetic moment and magnetic declination angle of the sample. The effectiveness of the method is proved by numerical simulation and experimental measurement. Our results indicate that the proposed method offers several advantages, including its ease of deployment, simplicity of operation, high accuracy, and robustness. It provides a feasible solution for laboratory-based magnetic moment measurements and rapidly detecting magnetic moments in industrial settings.

Percutaneous distal chevron osteotomy is associated with lower immediate postoperative pain and a greater range of motion than the open technique: A prospective randomized study.

The results of past studies comparing percutaneous techniques with traditional open techniques for hallux valgus are controversial. Therefore, this study aimed to compare the radiologic and clinical outcomes of percutaneous and open distal chevron osteotomies. Seventy-one patients with mild to severe hallux valgus deformity were randomized to undergo percutaneous distal chevron osteotomy (percutaneous group, n = 36) or open distal chevron osteotomy (open group, n = 35) between October 2019 and September 2020. Radiological and clinical outcomes were assessed preoperatively and postoperatively. Outcome measures included the foot and ankle outcome score, foot functional index, visual analogue scale (VAS) scores for pain, range of motion (ROM) of the first metatarsophalangeal (MTP) joint, hallux valgus angle, intermetatarsal angle, and first metatarsal shortening. Additionally, the first metatarsal declination angle was measured to evaluate sagittal malunion. The mean first metatarsal declination angle decreased significantly at 12 months postoperatively in both groups (p = 0.021 and p < 0.001 in the percutaneous and open groups, respectively), and the decrement was significantly greater in the open group (p = 0.033). The mean VAS score for pain on postoperative day one was 4.2 ± 1.9 and 5.3 ± 1.7 in the percutaneous and open groups, respectively (p = 0.019). The mean ROM of the first MTP joint did not change significantly after surgery, from 72.5 ± 7.5 preoperatively to 71.0 ± 9.5 at 12 months postoperatively in the percutaneous group (p = 0.215); however, it decreased significantly from 70.6 ± 7.3 preoperatively to 63.4 ± 10.4 at 12 months postoperatively in the open group (p < 0.001). There were no significant differences between the groups regarding other clinical outcomes. The percutaneous group showed a lower immediate pain level at postoperative day 1 and better ROM of the first MTP joint at 12 months postoperatively.

Trunk muscle activation in prone plank exercises with different body tilts.

Body tilt changes could affect the intensity/difficulty of core stability exercises, but there is still a lack of knowledge about its impact. To analyse the trunk muscles activation during prone plank exercises at different body tilts. Twenty-four young adults who performed recreational gymnastic activities participated in this study. Electromyography activity of the rectus abdominis (RA), external oblique (EO), internal oblique (IO) and erector spinae (ES) was recorded during the performance of six variations of the prone plank exercise (planking with feet supported on the ground [conventional horizontal position] and planking with feet supported on wall bars at five different heights increasing the angle tilt) and an inverted position exercise. The RA, EO and IO activation in all prone plank variations were higher than those observed in the conventional prone plank. In addition, the coefficient of variation of the muscle activation increased with the declination angle, reaching the highest values in the inverted position for the RA and ES muscles. The results seem to indicate that the body tilt variation could be used as an easy and inexpensive strategy for modulating the neuromuscular demands and the motor control challenge during planking exercises.

Is it necessary to graft the void defect during open reduction and internal fixation of calcaneal fractures?

There are still controversies on the effect of grafting during open reduction and internal fixation of calcaneal fractures. The aim of this study was to compare the radiological and functional outcomes in patients with or without intraoperative grafting. In a comparative retrospective study, among 442 operatively-treated calcaneal fractures, 60 patients with unilateral closed sanders type II intraarticular calcaneal fracture who underwent ORIF via lateral extensile approach using locking anatomical plates with at least 1year follow-up without any postoperative wound complication were enrolled. The patients were separated into 2 groups: with bone allograft and without bone allograft. The functional outcome of the patients was assessed using visual analog scale (VAS) for pain, the American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot scale, foot function index (FFI), and short-form (SF-36) health survey. Radiographic variables included Böhler angle, Gissane angle, calcaneal width, calcaneal height, and talar declination angle. Also, the differences (delta) of these values in comparison to the uninjured foot were calculated. The mean age was 39.1 ± 12.7 (range, 13-67) years with 54 males, 90.0%. No statistically significant differences were detected in age, gender, affected side, and subtypes of calcaneal fractures between the two groups (p > 0.05). The average follow-up was 25.1 (range, 12-48) months. The differences for all radiographic measurements and also, the delta values between the groups were not statistically significant, except talar declination angle which was more in cases without grafting (p = 0.007). Although the differences between the two groups regarding AOFAS ankle-hindfoot scale (p = 0.257), VAS for pain (p = 0.645), and FFI (p = 0.261) were not statistically significant; the group with bone graft experienced less pain (19.7 ± 22.0) than the other group (26.7 ± 22.8). The difference between the groups was not statistically significant (p = 0.87) according to the SF-36 questionnaire. Incorporating allografts into the void defects during ORIF of displaced intraarticular calcaneal fractures may not improve functional outcomes and recover postoperative radiological parameters. Therefore, routine use of allograft to fill the defects during ORIF of calcaneus may not be recommended. Of note, that these findings solely relate to the treatment of Sanders type II fractures. Comparative retrospective study.

The Latitudinal and Longitudinal Variation of the Semidiurnal Lunar Tide in the Ionosphere During 2013

AbstractThe present paper studies the latitudinal and longitudinal variation of ionospheric semidiurnal lunar tide (M2) perturbations in 2013 with total electron content (TEC) data. Results show that the latitudinal distribution of M2 exhibits longitudinal difference. At 100 ∼ 120°E and 80 ∼ 100°W longitudes, the strongest M2 perturbations in the northern and southern hemispheres roundly appeared at about 10° ∼ 20°N and 15° ∼ 25°S magnetic latitude (MLAT), respectively, which supports previous suggestion that the M2 maximized in the EIA crest regions. Moreover, the latitude range of M2 at 80 ∼ 100°W longitudes was wider than that at 100 ∼ 120°E longitudes, especially for southern hemisphere (SH). The M2 maximized at 20° ∼ 30°N MLAT in the northern hemisphere (NH) and was absent in the SH at 50°W ∼ 20°E longitudes, which was distinctly different than those at other longitudes. This abnormal behavior of latitudinal distribution of M2 may be caused by the large magnetic declination angle at 50°W ∼ 20°E longitudes. Meanwhile, the longitudinal variation and hemispheric asymmetry of M2 amplitude are different between NH winter (SSW period) and other seasons. The M2 amplitudes were stronger disturbances in the NH and in the American longitudinal sector in NH winter. However, in other seasons, the M2 amplitude was largest in Asian sector, and the M2 amplitude in NH was larger than SH at 0° ∼ 130°E longitudes, which was contrast to these at 0° ∼ 110°W longitudes. These differences of M2 variation between NH winter and other seasons may be related to the differences of the combined effects of the geomagnetic configuration and background conditions of the atmosphere and ionosphere.

Parameters That Can Be Used to Quantify Reduction Accuracy in Talar Neck Fractures and Malunions: A PRISMA-Compliant Scoping Review and Meta-Analysis.

Understanding the three-dimensional anatomy of the talar neck is essential in assessing the accuracy of reduction in talar neck fractures as well as for planning surgical correction for talar malunions. However, the geometrical parameters that describe this anatomy are sparsely reported in the orthopedics literature. We aimed to identify from the existing literature, geometrical parameters that describe the anatomy of the talar neck, determine how these are measured, and their normative values. A scoping literature review was conducted in accordance with thePreferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)extension for scoping reviews (PRISMA-ScR) guidelines. The primary searches were conducted on the PubMed, Embase, and Scopus databases. Any original research study looking at the human talus neck geometry was included. Parameters that described the anatomy of the talar neck were identified, andpooled estimates were determined by the random-effects meta-analysis model. Heterogeneity was assessed by the I2 test and leave-one-out meta-analysis. Subgroup analysis was done to compare the values of parameters between the Asian and Non-Asian populations. The risk of bias was assessed by the National Institutes of Health (NIH) Case Series Tool. The combined searches yielded 6326 results, of which 21 studies were included in the review and 15 in six different sets of metanalysis. The majority of the studies (n=19, 90.5%) evaluated adult tali, and only two (9.5%) evaluated pediatric tali.In most of the studies (n=13, 61.9%), talus neck geometry was evaluated on dry bones or anatomical specimens; evaluation by imaging techniques (radiographs, CT, MRI, and radiostereometric analysis) was used in eight studies, (39.1%). A total of eight different geometrical parameters (neck length, height, width, declination angle, inclination angle, torsion angle, circumference, and cross-sectional area) were identified. Except for talar torsion, variability was noted in methods of measurement of all other parameters. Subgroup analysis revealed that Asians had a higher neck height as compared to non-Asians; other parameters were not significantly different. Although the literature reports geometrical parameters to assess the talar geometry, the methods of measurement of these parameters are variable. Most of the available literature describes measurement techniques on cadaveric tali, and there is no literature on how these parameters should be measured on conventional CT or MRI slices. Further research needs to focus on the standardization of measurement techniques for these parameters on conventional CT and/or MRI scans.

Optimization Scheme of Measuring Accuracy of Bearing Seat Size Based on Machine Vision

At present, the size measurement of industrial workpieces is mainly manual measurement and CMM measurement, which cannot meet the requirements of high precision, high efficiency and low error rate in industrial production at the same time. In order to solve the above problems, this paper uses monocular vision technology to propose an optimization scheme of workpiece size measurement accuracy based on machine vision, which takes the height and declination Angle between the camera lens and the workpiece as variables. Firstly, the image was captured by camera calibration correction, and morphological methods such as gray-scale, denoising, expansion and corrosion were used for image pre-processing. Secondly, features were extracted using double-threshold canny edge detection algorithm and connected domain algorithm. Finally, the bearing seat size was measured using the minimum external rectangle algorithm. The experiment shows that the higher the distance between the camera lens and the stage, the larger the error is when the image information can be collected completely. The greater the Angle between the center of the camera lens and the center of the workpiece, the greater the error; The device not only meets the precision requirements, but also has the advantages of fast response speed, which can meet the needs of industrial applications.

Solar Radiation Forecasting Models and their Thermodynamic Analysis in Asaba: Least Square Regression and Machine Learning Approach

Least square regression and machine learning tools were used for the development of global solar radiation forecasting models for Asaba region. Data from the year 2013-2022 from Nigerian Meteorological Agency, Asaba was used for this study. The least square regression method was used to develop four global solar radiation -based models, tagged H1, H2, H3 and H4 with characteristic day length, solar declination angle, rainfall amount, etc. as its model terms while the machine learning models produced multilayer perceptron, coarse Gaussian model (SVM-based model) and XGBoost model. The prediction factors like mean bias error, mean percentage error, root mean square error, Nash-Sutcliffe equation, coefficient of correlation (R), t-test, and coefficient of determination (R2) were considered using the model terms. The results indicates that H4 model outperformed H1, H2, H3, machine learning models (SVM-based model, multilayer perceptron and XGBoost) and other existing models (MA-MME and MLR) with a mean percentage error value of 0.740, RMSE value of 46.588, Nash-Sutcliffe equation value of 0.739, higher R2 value of 0.7391, t-test value of 2.595E-24 and mean bias error value of -6.88E-12. Thus, H4 model results fell within accepted range. Additionally, the exergy of the global solar radiation of Asaba varied from 20-185 W/m2 which are good. This shows that a more efficient and ideal global solar radiation prediction model (H4) has been developed for Asaba and other regions that share similar climatic conditions.

Prediction of solar irradiance with machine learning methods using satellite data

ABSTRACT Solar energy is used in many domestic and industrial areas. To make maximum use of solar energy, it is important to know the irradiance value per unit area. Irradiance measurements are carried out at many stations. In cases where the irradiance value is not measured, empirical models are generally used. With the widespread use of machine learning methods in prediction problems in many fields, it has gained increasing popularity recently. This study aims to predict the solar irradiance of all cities in the Mediterranean region in Turkiye using statistical method and popular machine learning methods. The performances of these models are compared. Ensemble Learning methods (Gradient Boosting, Extreme Gradient Boosting) which are among the popular machine learning methods, and Artificial Neural Networks were used. The data used belong to 8 cities in the Mediterranean Region, Türkiye. Declination angle, wind speed, ambient temperature, relative humidity, and cloudiness index were chosen as input variables. When the results of the models established for each city are examined, it is seen that the models established with machine learning methods are more successful than statistical methods. The best results were obtained from models established with the Extreme Gradient Boosting method (R2 = 0.9993, MAPE = 0.0119).

The effect of spatial orientation of solar energy receiver on the energetic gain

The angle of incidence of solar radiation on the PV panel is a function of many factors: the angle of solar declination, the angle of latitude, the hour angle, the azimuth angle and the angle of receiver inclination to the ground. Optimization of the positioning of a solar energy receiver, considering the possible energetic gain, with the Liu-Jordan isothropic mathematical model has been made. The influence reflectivity coefficient of the ground and transparency coefficient of the atmosphere on the investigated angle has been taken into account. The computer simulation results have been presented and compared with those obtained by other authors.

A Single Oscillator-Excited Piezoelectric Actuator with Internal Contact Teeth.

The tail rotor of a helicopter, a crucial component, traditionally relies on a complex drive mode involving reducers and transmission gears. This conventional setup, with its lengthy transmission chain and numerous components, hinders miniaturization efforts. In response to this challenge, our paper presents a novel piezoelectric drive approach. Our objective was to suggest an innovative design capable of minimizing the components involved in the tail rotor drive. This design can be adjusted in size according to specific requirements and is effective up to a specified speed. Moreover, it facilitates the process of miniaturization and integration. The piezoelectric actuator's stator comprises an ultrasonic amplitude transformer, a ring, and three drive teeth. Utilizing the rod-like structure of the tail brace, the actuator is simplified by adhering ceramic sheets to it. The rotary piezoelectric actuator combines the first longitudinal mode of a rod with torus bending modes. The drive teeth then amplify the ring's displacement, facilitating rotor rotation. The resonant frequency and modal shape of the actuator were determined using the finite element method. Furthermore, an investigation was conducted to analyze the influence of the drive teeth positioning on the motion trajectory at the contact point. Theoretically, we infer that the declination angle of the drive tooth is a crucial parameter for achieving high speeds. To test our idea, we built three prototype stators with different drive tooth declination angles. Our actuator stands out for its cost-effectiveness, structural simplicity, compatibility with harmonic signals, and ease of miniaturization. It can be considered for the drive of the tail rotor of a microhelicopter.

Skillion Roof Design to Get Optimum Solar Radiation in Yogyakarta

Electrical energy is energy that cannot be released from daily activities at home, all elec-tronic equipment requires electrical energy, one source of electrical energy is the electrici-ty company PT. PLN (Persero) and as an alternative source of electrical energy, a home can use solar panels installed on the roof as a small scale power generator or can be called Solar Home System (SHS), but electrical energy obtained is very dependent on the radia-tion received by the solar panels, therefore, to obtain optimum solar radiation, it is neces-sary to calculate the azimuth angle and tilt angle which can be used as a reference for in-stalling solar panels. So mathematical calculations are needed to calculate the maximum azimuth angle and tilt angle. Mathematical modeling is used to calculate solar energy in-stalled at coordinates 7.7° south latitude, in that coordinate, average solar radiation can get from Meteorological, Climatological, and Geophysical Agency on horizontal surface, then calculation the declination angle, latitude angle, hour angle, azimuth angle and tilt angle to get value of incidence angle. Value of the declination angle, latitude angle, and hour angle are constant, while the azimuth angles divide into four directions, it’s 0°, 90°, 180°, and 270° and the tilt angles are 20°, 25°, and 30° on skillion roof design. The results of the calculation and analysis of the movement of the sun for one year show that, by calculating the average solar radiation in a year, the roof of the house in the form of a skillion with an azimuth angle in the 0° gets the most optimal solar energy at an angle of 20° with an aver-age solar radiation of 442,96 W/m2 in one year.

An evaluation of subtalar titanium screw arthroereisis for the treatment of symptomatic paediatric flatfeet - early results

BackgroundIdiopathic flexible flatfoot is a common condition in children which typically improves with age and remains asymptomatic. However, the condition can sometimes be more severe, and cause mechanical impairment or pain. The aim of the study was to perform a prospective clinical, radiological, podoscopic and pedobarographic assessment (static and dynamic) of subtalar titanium screw arthroereisis for the treatment of symptomatic, idiopathic, flexible flatfeet.MethodsA prospective, consecutive, non-controlled, cohort, clinical follow-up study was performed. In total, 30 patients (41 feet), mean age 10 (6 to 16 years), were evaluated. Clinical and standing radiological assessments, static and dynamic pedobarography, as well as podoscopy, were performed before surgery and at final follow-up.ResultsTreatment was associated with significant improvements in heel valgus angle, radiographic parameters (lateral and dorso-planar talo-first metatarsal angle, calcaneal inclination angle, talar declination angle, longitudinal arch angle) and podoscopic parameters (Clark’s angle, Staheli’s arch index and Chippaux-Smirak index). Significant increases were noted for lateral loading, forefoot contact phase and double support / swing phase, and reduced medial loading (dynamic pedobarography), as well as lateral midfoot area and loading, but decreased were observed for medial forefoot loading (static pedobarography). Four patients reported persistent pain in the sinus tarsi region (six feet), and in one case, the implant was replaced for a larger one due to undercorrection. No overcorrections or infection complications were noted in the study group.ConclusionsSubtalar arthroereisis is a minimally-invasive and effective surgical method for treating symptomatic, idiopathic, flexible flatfeet; it has an acceptable complication rate with good early clinical results.Level of evidenceII b.

Mid-term assessment of subtalar arthroereisis with Talar-Fit implant in pediatric patients with flexible flatfoot and comparing the difference between different sizes and exploring the position of the inserted implant.

Subtalar arthroereisis (STA) has gained growing acceptance as a viable approach solution for the management of pediatric flexible flatfoot. However, STA still remains controversial. The purpose of this study is to assess the effect of STA using the Talar-Fit implant for treating pediatric flexible flatfoot. Specifically, the aims of the study are as follows: first, to present the mid-term outcomes of STA using the Talar-Fit implant; second, to compare the radiographic and clinical outcomes associated with varying sizes of Talar-Fit implant; and third, to analyze the optimal position of the inserted implants. A retrospective analysis was conducted on a cohort of 57 pediatric patients diagnosed with flexible flatfoot (77 feet) who underwent STA utilizing Talar-Fit between January 2014 and December 2021. The participants were categorized into five groups according to the size of the implant: Group 8, Group 9, Group 10, Group 11, and Group 12. The evaluation included the assessment of clinical function using the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hind foot score, as well as the assessment of radiographic data such as the calcaneal pitch angle (CPA), lateral Meary angle (LMA), talar declination angle (TDA), and medial longitudinal arch angle (MLAA) were evaluated. Furthermore, the position of the inserted implants was also recorded, including angle, depth, and distance. The comparison of pre- and postoperation was conducted using the paired Student's t-test, whereas the analysis of differences among subgroups was performed using the Wilcoxon rank-sum test. A P-value < 0.05 is considered statistically significant. In total, 57 pediatric patients (77 feet) were successfully followed-up for an average period of 26.8 months. The overall AOFAS score significantly improved from 58.6 ± 10.9 to 85.2 ± 8.6 (P < 0.001). Furthermore, the LMA decreased from 20.3° ± 3.6° to 4.5° ± 1.3°, the CPA increased from 14.8° ± 1.6° to 23.6° ± 2.7°(P < 0.05), the TDA decreased from 40.2° ± 2.3° to 25.5° ± 3.2°(P < 0.05), and the MLAA decreased from 140.1° ± 2.8° to 121.4° ± 3.9°(P < 0.05). No statistically significant differences were observed among subgroups regarding the final outcomes. The improvements of CPA, TDA, and MLAA among different groups were significantly different; however, the adjusted P-values were all greater than 0.05. The implant were inserted at a mean angle of 89.5° ± 2.4°, a mean depth of 0.9 mm ± 2.1 mm, and a mean distance of 9.9 mm ± 0.9 mm. Eight patients experienced complications, including six cases of pain occurrence and two cases of implant dislocation. STA with Talar-Fit has demonstrated satisfactory mid-term outcomes. A Talar-Fit with a larger size may demonstrate a superior effect when compared with that of a smaller size. The implants were inserted in a similar position, indicating that the medial edge of the implant may be possible to transcend the midline of the talus neck.

What Do We Know About the Pathoanatomy of Talar Neck Malunions? Results From a 3D Morphometric Analysis

Category: Trauma; Hindfoot Introduction/Purpose: Malunions of the talar neck significantly alter the foot biomechanics and predispose patients to arthrosis and poor functional outcomes. Recent interest has focused on the surgical correction of these deformities, with corrective talar neck osteotomy emerging as a safe and effective treatment for malunions without ankle arthrosis. While a talus malunion is traditionally thought to cause a varus deformity due to the shortening of the medial talar neck, the pathoanatomy of these deformities remains unclear and sparsely reported in the literature. Therefore, this study aimed to investigate the three- dimensional changes in morphometric parameters of the talar neck after malunion and to determine how these changes affect the architecture of the foot. Methods: Adult patients with a talar neck malunion without ankle arthrosis (Rammelt and Zwipp Type 1-3) were prospectively included. Weight-bearing (WB) AP, Lateral and long axial radiographs, and CT scans of both feet were obtained. 3D models of both tali were generated. The malunion side was mirrored and superimposed on the normal side, and distance maps were generated to identify pathoanatomic changes. Deviation of the talar neck in the axial plane (declination angle [DA]), sagittal plane (inclination angle [IA]), coronal plane (torsion angle [TA]) as well as the medial and lateral neck lengths (MNL and LNL) were measured on the 3D talus models using a semi-automated GEOGEBRA script. AP and Lateral Meary’s angle and the hindfoot moment arm (HMA) was determined on WB radiographs. The t-test was used to compare the talar neck parameters, and correlation coefficients were used to determine the association between talar neck parameters and foot radiographic parameters. Results: 10 patients, 6 males, and 4 females, with a mean age of 32.4 years were included. There were 4 cases of Rammelt and Zwipp Type 1 deformity, and 6 cases of Type 3 deformity. Axial plane changes included varus deviation of the talar neck in 8 cases and valgus deviation in 2. Sagittal plane changes included dorsiflexion of the talar neck in 4, neutral alignment in 3 cases, and plantarflexion in 3 cases. The TA was increased in all cases. TA and MNL had a moderate positive correlation with AP Meary’s angle and, and a moderate negative correlation with Lateral Meary’s Angle. DA and MNL had a moderate positive correlation with the HMA. Conclusion: Talar neck malunions are complex three-dimensional deformities resulting in the common varus and dorsiflexion variants, as well as less common valgus and plantarflexion variants. Despite the variation in malunion types, all cases are characterized by an increased TA. Furthermore, the combination of increased TA and DA and decreased MNL leads to forefoot adduction and hindfoot varus. Due to the intricate and diverse three-dimensional nature of these deformities, surgeons must conduct a comprehensive evaluation of the pathoanatomy before planning surgical correction.

Relative Position of the First Ray and Patient Reported Outcome Measures Following the Modified Lapidus Procedure: a Weightbearing CT Study

Category: Bunion; Midfoot/Forefoot Introduction/Purpose: Hallux valgus is a complex three-dimensional deformity, and the modified Lapidus is a commonly used procedure to correct moderate to severe deformities. Shortening and elevation of the first ray are two potential factors that may predispose to increased pressure on the lesser metatarsal heads. However, there is currently no consensus regarding optimal position of the first ray following the modified Lapidus. The purpose of this study is to evaluate the impact of the position of the first ray on patient reported outcome measures. Methods: This retrospective study identified 68 patients (72 feet) from a prospectively collected foot and ankle registry who underwent the modified Lapidus bunionectomy over a 4-year period at a single institution with an average follow-up of 20.3 months (Table 1). Patients were included if they were over 18 years of age, had pre and post-operative weightbearing CTs (WBCT), and pre- and minimum 1-year post-operative PROMIS scores. PROMIS scores from 6 domains including Physical Function, Pain Interference, Pain Intensity, Global Physical Health, Global Mental Health, and Depression were evaluated and compared pre- and post-operatively. Radiographic parameters including 1st metatarsal declination angle (MDA), relative metatarsal length (RML), sesamoid position, metatarsus primus elevatus (MPE), hallux valgus angle (HVA), Intermetarsal angle (IMA), and distance from the metatarsal head and sesamoid from the floor were measured and compared before and after surgery. Paired t- tests were employed to evaluate the significance of pre- to post-operative changes. Results: PROMIS physical function, pain interference, pain intensity, and global physical health improved significantly following the modified Lapidus (all p&lt;.001), however, scores did not show significant correlation with shortening of the first ray. The length of the 1st metatarsal relative to the 2nd decreased by an average of 2.7mm following the procedure when measured on WBCT (p &lt;.001), and 2.6mm when measured on plain radiographs (p &lt;.001). There was no significant change in elevation of the first metatarsal (MPE) relative to the 2nd (3.5mm to 3.47, p&gt;=.9). The distance from the sesamoid to floor increased significantly by 1.42mm and the metatarsal to floor distance increased by 2.22mm (both p&lt;.001). The MDA increased from 20.22 to 21.89 (p &lt;.001). Symptoms of transfer metatarsalgia were noted in 5/72 feet (6.9%). Conclusion: This study revealed that the Lapidus bunionectomy resulted in significantly improved PROMIS scores, however, the scores did not correlate strongly with radiographic parameters for first ray shortening or elevation. The relative shortening of the first ray that occurs with the modified Lapidus procedure is minimal (2.7mm) and does not appear to have a significant adverse impact on patient reported outcome measures. Reduction of the sesamoids under the metatarsal head increased the distance from the metatarsal to floor, but did not result in any significant increase in MPE.

Do Arch Supports Alter Foot Alignment in Patients with Metatarsalgia? A Weightbearing CT and x-ray Study

Category: Midfoot/Forefoot; Lesser Toes Introduction/Purpose: Arch-support insoles are frequently included in the treatment plans for common foot ailments including metatarsalgia. Literature has demonstrated that insoles with metatarsal and arch support could relieve walking pain and improve patient-reported measures of function in metatarsalgia. The purpose of this study was to examine alterations in foot alignment among metatarsalgia patients who used arch support insoles. Methods: A clinical trial was initiated after the approval by the institutional review board. Patients with metatarsalgia (age: 18-65 y/o) were included after they consented to participate. Individuals with open wounds, feet asymmetry, using assistive device or brace, and those with BMI more than 35 were excluded. Participants underwent weightbearing computed tomography (WBCT), and weight-bearing x-ray of their feet while standing barefoot or on the insoles (Good Feet™, Dr.’s Own, LLC). The radiological measurements on WBCT and X-rays conducted in these patients are shown in Table 1. The Wilcoxon-Signed Rank test was used for comparison of the continuous measurements, and the interobserver reliability was analyzed with Intraclass Correlation Coefficient (ICC). Results: Ten patients with a mean age of 46.9±13.06 years were included in the study. Observed changes on X-rays include decreased 4th-5th intermetatarsal angle (p=0.04), 2nd-4th/2nd-5th metatarsal tangent angles (p=0.003, p=0.001), and 1st metatarsal length on antroposterior (AP) view (p=0.02). Also, 1st metatarsal declination angle (p=0.002), and talo-first metatarsal angle on AP view (p=0.05) were increased. No significant changes on the WBCT were found, except for a decrease in the first metatarsal pronation angle (p=0.02). Conclusion: Arch support insoles can bring about anatomical changes especially in the forefoot area of patients with metatarsalgia. While the causal correlation between these changes and alleviation of the symptoms cannot be proven based on our data, these outcomes can guide future clinical trials comparing different treatment for metatarsalgia to determine contributing factors to the healing process of this condition.