Edge Angle Research Articles

Combined Borderline Acetabular Dysplasia and Increased Femoral Anteversion Is Associated With Worse Outcomes in Female Patients Undergoing Hip Arthroscopy for Femoroacetabular Impingement

To determine the relationship of increased femoral anteversion and borderline acetabular dysplasia on the outcomes of hip arthroscopy for femoroacetabular impingement (FAI) in a female cohort of patients. This is a retrospective study of female patients undergoing hip arthroscopy for FAI. All patients had preoperative radiographs and computed tomography scans from which lateral center edge angle (LCEA) and femoral anteversion were measured. Patient outcome was quantified by preoperative and post-operative international hip outcome tool(iHOT)-12. All patients had follow-up at two to four years postoperatively. Published values for minimum clinically important difference(MCID), substantial clinical benefit(SCB), patient acceptable symptomatic state(PASS), and a normal or abnormal hip were used to determine outcome as well as the final score and delta of the iHOT12. There were 243 female patients included in the cohort (83% follow-up) that had iHOT12 scores at two-to-four-year follow-up (Mean 36.9 months). Females with combined LCEA≤25 degrees and Femoral anteversion over 20 degrees had lower Final IHOT12(p=0.001) and Delta iHOT12(p=0.010) and were less likely to achieve a normal hip(p=0.013), MCID(p=0.018), SCB(p<0.001), or PASS(p<0.001) and more likely to have an abnormal hip(p=0.002). In addition, patients with an LCEA≤25 degrees and normal femoral version were less likely to achieve a normal hip(p=0.013), SCB(p<0.001) and PASS(p<0.001) compared to those with normal acetabular coverage (all p<0.05). There was no difference in these outcome measures between the groups with an LCEA over 25 degrees with or without increased femoral version. Female patients with femoral anteversion over 20 degrees and borderline acetabular dysplasia did poorly after hip arthroscopy. However, those with increased femoral anteversion and normal acetabular coverage had outcomes similar to control hips. Level 4 case series.

A Deep Learning Algorithm for Radiographic Measurements of the Hip in Adults-A Reliability and Agreement Study.

Hip dysplasia (HD) is a frequent cause of hip pain in skeletally mature patients and may lead to osteoarthritis (OA). An accurate and early diagnosis may postpone, reduce or even prevent the onset of OA and ultimately hip arthroplasty at a young age. The overall aim of this study was to assess the reliability of an algorithm, designed to read pelvic anterior-posterior (AP) radiographs and to estimate the agreement between the algorithm and human readers for measuring (i) lateral center edge angle of Wiberg (LCEA) and (ii) Acetabular index angle (AIA). The algorithm was based on deep-learning models developed using a modified U-net architecture and ResNet 34. The newly developed algorithm was found to be highly reliable when identifying the anatomical landmarks used for measuring LCEA and AIA in pelvic radiographs, thus offering highly consistent measurement outputs. The study showed that manual identification of the same landmarks made by five specialist readers were subject to variance and the level of agreement between the algorithm and human readers was consequently poor with mean measured differences from 0.37 to 9.56° for right LCEA measurements. The algorithm displayed the highest agreement with the senior orthopedic surgeon. With further development, the algorithm may be a good alternative to humans when screening for HD.

Acetabular deficiency in borderline hip dysplasia is underestimated by lateral center edge angle alone

IntroductionIn hip preservation surgery, the term “borderline hip dysplasia” was used when the lateral center edge angle (LCEA), historically described by Wiberg, measured 18–25°. In recent years, several radiographic parameters have been described to assess the antero posterior coverage of the femoral head, for example, the anterior and posterior wall index (AWI and PWI). This allowed an increasingly comprehensive understanding of acetabular morphology and a questioning of the borderline definition.Material and methodsA retrospective review of 397 consecutive hips was performed, all treated with triple pelvic osteotomy (TPO) due to symptomatic hip dysplasia. On all preoperative pelvic radiographs with a LCEA of 18–25°, acetabular index (AI), AWI and PWI were measured. With these values, the hips were categorized into laterally, antero-laterally and postero-laterally dysplastic and stratified by gender. Intra- and interobserver correlation of the parameters was analyzed by intraclass correlation coefficient (ICC).ResultsAccording to LCEA, 192 hips were identified as “borderline dysplastic”. Based on AWI and PWI, the categorization resulted in 116 laterally dysplastic (60.4%), 33 antero-laterally (17.2%) and 43 postero-laterally dysplastic hips (22.4%). Gender stratification revealed that male acetabula seemed to be slightly more postero-laterally deficient than female (mean PWI 0.80 vs 0.89; p = 0.017). ICC confirmed highly accurate and reproducible readings of all parameters.ConclusionThe rather high proportion of symptomatic hips labelled borderline dysplastic suggested, that there might be substantial acetabular deficiency not recognizable by LCEA. Comprehensive deformity analysis using LCEA, AI, AWI and PWI showed, that 40% of these hips were deficient either antero-laterally or postero-laterally. Male acetabula were more deficient postero-laterally than female.

Optimized design of structural parameters of Si3N4-based ceramic tools with variable cross-section

Through theoretical analysis and finite element simulation experiments, this paper proposes an optimal design method for the structural parameters of ceramic tools with variable cross-sections. On this basis, the tool angles of Si3N4-based ceramic tools for cutting inconel 718 high-temperature alloy are investigated, including rake angle γ0 = −5°, clearance angle α0 = 5°, cutting edge inclination λs = −2°, cutting edge angle Kr = 45°. By comparing the main cutting force, temperature and chip-breaking effect of flat face and three different groove ceramic tools, it is found that straight chip breaker has the most obvious optimization effect, main cutting force is 14.5% lower than that of the flat face, the temperature is reduced by 10.2%, and radius of chip curl curvature is the smallest, which is easy to break chips.

Simultaneous femoral head reduction osteotomy (FHRO) combined with periacetabular osteotomy (PAO) for the treatment of severe femoral head asphericity in Perthes disease

BackgroundThe purpose of this study is to describe the midterm clinical and radiologic outcomes of concurrent femoral head reduction osteotomy (FHRO) and periacetabular osteotomy (PAO) in Legg–Calvé–Perthes disease (LCPD) patients with major aspherical femoral head deformities.MethodsThe study included four Perthes patients in Stage IV of Waldenstrom’s classification with a mean age of 10.5 and severe femoral head asphericity. They were treated with a combination of FHRO + PAO and followed for at least 2 years. An evaluation of the radiological outcome of the surgery was carried out based on the lateral center to edge angle (LCEA), the anterior center to edge angle (ACEA), the Tönnis angle, the head sphericity index, the Stulberg classification, the extrusion index, and Shenton’s line integrity. An evaluation of the clinical outcome was made by evaluating hip range of motion (ROM), Harris hip score (HHS), and Merle d’Aubigne´-Postel score.ResultsAll radiographic measures improved; three patients were classified as Stulberg class II and one as class III. The LCEA, ACEA, and Tönnis angle improved by 29° (from 3° to 32°), 16° (from 14° to 30°), and − 10° (from 18° to 8°), respectively. The mean femoral head sphericity index and extrusion index improved by 12% (from 83 to 95%) and − 33% (from 40 to 7%). No disruption was observed in the postoperative Shenton’s line. According to HHS, all patients have shown excellent hip function, which improved by 27 points (from 69 to 96). Moreover, the hip ROM was increased from 222° to 267°. The follow-up period did not reveal any serious postoperative complications, such as osteonecrosis or conversion to arthroplasty.ConclusionsCombined FHRO with PAO may improve the hip joint’s morphology and function in patients with residual femoral head deformity and acetabular dysplasia due to LCPD. Despite being considered a complex and demanding hip surgery, these results suggest a more widespread implication of the salvage procedure.

Evaluation of the performance of very narrow tines with different geometrical structures for tilling natural grassland

Natural grassland is an important ecological barrier in northern China and using mechanised improvement methods to restore degraded natural grassland is significant. This paper aimed to evaluate the working performance of different very narrow tines through full-factorial experiments, and provide basic references for design novel and specialised tillage tools applicable to natural grasslands. The thickness, cutting edge angle, and rake angle were chosen as the independent variables, and related working resistance and soil disturbance indicators were selected as the dependent variables. Different shank-type tines and a test bench were designed and manufactured. Field experiments under different working depths were conducted. The results showed that the thickness, rake angle, and cutting edge angle all had statistically significant influences on the working resistance (P < 0.05), and interaction functions were found between these three factors. The soil overturning rate, soil bulkiness value, and soil disturbance coefficient created by the tines were in the ranges of 0.5–14.5%, 12–40%, and 50–68%, respectively. The tine with the thickness of 14 mm, the rake angle of 45°, and the cutting edge angle of 60° provided the best working performance. The grassland surface disturbance situation, soil overturning rate, disturbed cross-section area, soil bulkiness value, and soil disturbance coefficient well described the disturbance situation. The working depth and geometrical parameters of the tines all had influence on the working resistance and soil disturbance which should be considered together as the evaluation factors of the working performance of special tines for tilling natural grasslands. • Thickness, rake angle, and chamfer angle all significantly affect working resistance. • Soil disturbance coefficient of the grassland produced by shank-type tines is 50–68%. • Shank-type tine with chamfers cause low soil disturbance and small roots' damage. • Having cutting edge or not causes big differences in the soil overturning rate. • Rake angle of 45°, chamfer angle of 60°, thickness of 14 mm are optimum combination.

Factors affecting return to sports after eccentric rotational acetabular osteotomy

BackgroundAlthough eccentric acetabular rotation osteotomy (ERAO) is an effective treatment for developmental dysplasia of the hip (DDH), there is little information about return to sports after ERAO. This study aimed to investigate 1) the patient factors that influence the return to sports after ERAO, 2) whether postoperative sports participation will affect future osteoarthritis progression. HypothesisSome factors affect the return to sports after ERAO. Patients and methodsOf 503 patients who underwent ERAO from 1990 to 2010, 124 who had been continuously participating in sports preoperatively (average 13.2 years after surgery) were included. Patient demographics of sex, age, body mass index, unilateral to bilateral case ratio, history of treatment for childhood DDH, preoperative Kellgren-Lawrence (KL) grade, center edge angle, joint congruency, Harris hip score, complications and the survival rate were compared between the S group (patients who participated in the same sports preoperatively) and N group (patients who could not participate in sports postoperatively). ResultsSeventy-two (58%) and 52 patients (42%) in the S and N groups, respectively, had an overall return to sports rate of 64% (79 patients). The most common sports that patients participated in were swimming (30 patients [24%]), jogging (12 [10%]), and golf (10 [8%]) preoperatively, and swimming (14 patients [11%]), golf (8 [6%]), and jogging (8 [6%]) postoperatively. There were no significant differences between both groups in terms of sex, age, body mass index, unilateral to bilateral case ratio, history of treatment for childhood DDH, preoperative KL grade, and joint congruency. There was a significant difference in patient factors between the S (11 joints [14%]) and N (20 joints [38%]) groups only when the preoperative center edge angle was <0°. There was no significant difference in the preoperative Harris hip score and the final survey between the S (73.2±4.6 and 93.4±7.2) and N (72.5±4.8 and 92.1±7.4) groups. Complications showed no significant differences between the five patients (7%) in the S group and six patients (13%) in the N group. The KL grade progressed in 10 cases (grade II to III in 2 cases and grade III to IV in 8) in the S group and 8 cases (grade II to III in 1 case and grade III to IV in 7 cases) in the N group. The 10-year and 20-year joint survival rates with THA conversion as the endpoint were 98.1% (95% CI: 87.4%–99.7%) and 83.7% (95% CI: 62.6%–93.4%) in the S group and 100% (95% CI: 70.7%–99.3%) and 95.2% (95% CI: 12.6%–92.6%) in the N group, respectively. In the evaluation of factors affecting sports return by logistic regression analysis, only one significant factor (odds ratio 3.42, 95% confidence interval: 1.58–7.42, p<0.01) was the preoperative center edge angle <0°. DiscussionThe chief factor affecting the return to sports after surgery was a preoperative center edge angle <0°; moreover, the continuation of sports did not affect the subsequent progression of osteoarthritis or THA conversion. Level of evidencelevel III, cohort study.

Winter sports nation Germany-injuries in alpine ski racing and mass sports : Statistics and injury mechanisms in winter sports and current trends in sports science

In Germany, winter sports are very popular. About 7million people go skiing at least 6days per season. The German national winter teams won about 50% of the Olympic medals for the last several Olympic games. The downside of winter sports is the everlasting high number of injuries. This affects both professionals and the large number of amateur skiers. The ASU institute of German insurances and skiing association find adecreasing number of injuries overall and a decreasing number of inpatient stays in hospitals. Still, the knee is the most injured region of the body. There is an increasing number of ACL ruptures within the knee lesions. The numbers in professional teams have been monitored with the FIS surveillance system since 2006. The highest rates of knee injuries (41.3%) are found with the ski world cup teams all over the world. The most common injury mechanism is the slip-catch mechanism. In current sports science examinations of the German skiing association there are extremely high forces of more than three times the body weight found on the body during skiing. Slalom skiing is especially affected. To understand the popular carving ski technology, you must know about the waist and the edge angle of the ski. There can be enormous forces coming along with the skis that can hardly be controlled by the skier.

Effects of physical stress in alpine skiing on psychological, physiological, and biomechanical parameters: An individual approach.

Alpine skiing is an attractive winter sport that often includes mental and physical demands. Since skiing is often done for several hours, fatigue processes occur that might lead to action errors associated with a higher risk of accidents and injuries. The aim of this study was to investigate the timing of changes in subjective, physiological, and biomechanical parameters during a physically demanding, standardized, non-competitive alpine skiing session. A group of 22 experienced male skiers carried out 10 runs, each lasting between 150 and 180 s, at a turn rate of 80 turns per minute with their best skiing technique. Immediately after the run, skiers reported ratings of fatigue, and other affective states. During skiing, breathing pattern and biomechanical data of the ski turns as radial force, turn duration, edge angle symmetry, and a composed motion quality score were recorded. Analyses of variances on skiers showing signs of fatigue (n =16) revealed that only the subjective data changed significantly over time: fatigue and worry increased, vitality and calm decreased. Subsequently, individual change points analyses were computed to localize abrupt distribution or statistical changes in time series data. For some skiers, abrupt changes at certain runs in physiological and/or biomechanical parameters were observed in addition to subjective data. The results show general effects in subjective data, and individual fatigue-related patterns concerning the onset of changes in subjective, physiological, and biomechanical parameters. Individuality of response to fatigue should be considered when studying indicators of fatigue data. Based on the general effects in subjective data, it is concluded that focusing on self-regulation and self-awareness may play a key role, as subjective variables have been shown generally sensitive to the physical stress in alpine skiing. In the future, customized algorithms that indicate the onset of fatigue could be developed to improve alpine skiers' self-awareness and self-regulation, potentially leading to fewer action errors.

A flexible Python-based touchscreen chamber for operant conditioning reveals improved visual perception of cardinal orientations in mice.

Natural scenes are composed of a wide range of edge angles and spatial frequencies, with a strong overrepresentation of vertical and horizontal edges. Correspondingly, many mammalian species are much better at discriminating these cardinal orientations compared to obliques. A potential reason for this increased performance could be an increased number of neurons in the visual cortex that are tuned to cardinal orientations, which is likely to be an adaptation to the natural scene statistics. Such biased angular tuning has recently been shown in the mouse primary visual cortex. However, it is still unknown if mice also show a perceptual dominance of cardinal orientations. Here, we describe the design of a novel custom-built touchscreen chamber that allows testing natural scene perception and orientation discrimination performance by applying different task designs. Using this chamber, we applied an iterative convergence towards orientation discrimination thresholds for cardinal or oblique orientations in different cohorts of mice. Surprisingly, the expert discrimination performance was similar for both groups but showed large inter-individual differences in performance and training time. To study the discrimination of cardinal and oblique stimuli in the same mice, we, therefore, applied, a different training regime where mice learned to discriminate cardinal and oblique gratings in parallel. Parallel training revealed a higher task performance for cardinal orientations in an early phase of the training. The performance for both orientations became similar after prolonged training, suggesting that learning permits equally high perceptual tuning towards oblique stimuli. In summary, our custom-built touchscreen chamber offers a flexible tool to test natural visual perception in rodents and revealed a training-induced increase in the perception of oblique gratings. The touchscreen chamber is entirely open-source, easy to build, and freely available to the scientific community to conduct visual or multimodal behavioral studies. It is also based on the FAIR principles for data management and sharing and could therefore serve as a catalyst for testing the perception of complex and natural visual stimuli across behavioral labs.

Computational study of hydrogen and air co-flow jets mixing in dual-combustor ramjet in presence of ramp shock generator

Flame stabilization distribution and efficient fuel mixing are highly significant in the performance of ramjet engine. In this paper, numerical studies are done to investigate the supersonic combustion of hydrogen and air co-flow in presence of the ramp edge. In this study, flame maintenance and combustion formation in a dual-combustion ramjet engine are fully investigated. The primary emphasis of this work is to disclose the impact of produced shocks due to the existence of ramp edge on the structure of fuel and air-jet immediately downstream of injector. The shock interactions of two different angles (10 deg and 30 deg) of the ramp edge are investigated. Favre-averaged conservation equations are considered for the simulation of compressible flows inside the combustor. Various mechanisms expressing the flame spreading characteristics are also examined. Depending on the angle of the ramp edge, the produced shock waves influence on size and strength of vortices. Our findings also show that high angles of ramp edge augment the fluctuation of the vortices by the splitter and consequently, fuel mixing enhances in the combustion chamber of ramjet engine. Our findings also confirm that the similar jet pressure would be more effective on the vortex production downstream of the splitter. The application of ramp edge with angle of 30 deg would increase average momentum thickness of the mixing layer up to 55%.

Role of carbon material surface functional groups on their interactions with aqueous solutions

• The surface OCFG of the CM based on walnut shells were determined by Boehm titration method (C-OH = 1.15; C=O = 0.87; C-OH = 6.31 mol/g). • The acid-base nature of the CM surface was proved by the obtained dependences of the ζ-potential = f (C el , pH). • Cyclic voltammetry revealed that at pH < 2 and potentials of 0.45-0.55 V pronounced peaks are observed in the anodic region, which corresponds to the quinone/hydroquinone system. • Acid-base surface centers of CM were quantified by the adsorption indicator method. In this work, the fundamental study of the surface functional groups' role of the carbon material based on walnut shells in water solutions was studied. Functional groups (FG) were evaluated by Boehm’s titration method, electrochemical impedance spectroscopy, spectrophotometric method, etc. The surface oxygen-containing functional groups (OCFG) was determined quantitatively by Boehm method: C(-C-OH) = 1.15 mmol/g; C(-C O) = 0.87 mmol/g; C(–COOH) = 6.31 mmol/g. By the method of edge angle wetting the influence of OCFG on the formation of a hydrophilic functional layer on the surface of carbon material at different electrolyte media and adhesion works were found. The results of ζ-potential measurements as a function of solution pH allowed us to characterize the surface redox (acid-base) centers of the carbon material. Electrochemical impedance spectroscopy results show that surface OCFGs have a large influence on carbon material capacity characteristics.

Minimally Invasive Radiographic Evaluation of the Dysplastic Hip Joint Configuration in Terms of Surgical Treatment with Hip Preservation by PAO.

Residual developmental dysplasia of hip (RDDH) is a factor of early osteoarthritis of the hip. The main problems are pain and instability of the hip joint due to inadequate coverage of the femoral head by the acetabulum. The purpose of this study was to radiologically evaluate RDDH after Bernese periacetabular osteotomy (PAO) and to compare RDDH to healthy hips. The radiological parameters of RDDH treated by PAO were retrospectively evaluated. Digital AP pelvic radiographs were taken, including parameters of central edge angle and femoral head coverage, medialization, distalization, and ilio-ischial angle. Clinical assessment is based on the VAS scale. The study group consisted of patients with RDDH, and the control group consisted of patients without RDDH. After PAO radiological parameters decreased: medialization by 2.68mm, distalization by 3.65mm, and ilio-ischial angle by 2.62°. However, there was an increase in the parameters: CEA by 17.61° and FHC by 16.46%. There was a mean 3 point decrease in pain on the VAS scale. There was also a statistically significant radiological difference in the structure of dysplastic hip joints before surgery and healthy hip joints of the control group. Radiological studies confirmed the effectiveness of the PAO method in the treatment of RDDH. Based on all radiological parameters, differences between healthy and dysplastic hip joints were demonstrated. We believe that a thorough understanding of the values of radiological parameters used to describe dysplastic hip joints will allow us to improve the imaging diagnosis of this condition.

Morphometric study of acetabular depth and coverage and their clinical importance

To measure acetabular parameters and to compare parameters of acetabulum between men and women, and right and left sides. The study was conducted in PNS Shifa Hospital, Karachi from January to June 2021. Anteroposterior radiographs of both hips of 70 adults aged 20-70 years were included. The study consisted of 35 men and an equal number of women. We measured acetabular depth, femoral head coverage, acetabular inclination and acetabular depth and width. The acetabular depth was measured using Wiberg's central edge (CE) angle and Sharp angle techniques. Femoral head coverage was determined using measurements between medial edge of hip joint space, lateral edge of acetabulum and femoral head. To determine acetabular inclination, Tönnis angle was measured. Acetabular depth & width ratio (ADR) was evaluated by dividing acetabular width by depth, and multiplying by 100. There was significant increase in Sharp angle and Tonnis angle in females on the left side as compared to males. Wiberg's central edge angle and acetabular width to depth ratio showed insignificant increase in males as compared to females, whereas values of femoral head coverage were insignificantly more in women. The acetabular parameters were insignificantly different in gender and between right and left sides, although mean values were within normal range. The larger ADR ratio in men was most likely due to increased body weight in them as compared to women.

Power Consumption Influence Test of Castor Disc-Cutting Device

This study theoretically analyzed the cutting process of castor and determined the structural parameters of the key component of the castor disc-cutting device, aiming to obtain the optimal operation parameter combination and reduce the cutting resistance and power consumption during the harvesting process. The effects of the cutting-disc thickness, cutting-disc rotational speed, feeding speed, and edge angle on the cutting power consumption were studied using an orthogonal rotation combination experiment. The response surface method was used to optimize the parameters, and the mathematical relationship model between the cutting power consumption and each factor was established to determine the optimal parameter combination for disc cutting. The simulation results showed that the optimal combination of cutting parameters was cutting-disc thickness of 3 mm, cutting-disc rotational speed of 550 r/min, feeding speed of 0.6 m/s, and edge angle of 20°. Under these conditions, the cutting power consumption was 1.20375 J. The test results were basically consistent with the model prediction results. Therefore, this study provided a theoretical basis and reference for the design and improvement of castor harvesters.

Optimization of Francis Turbine Runner for Variable Speed Operations with minimization of sediment erosion

Sediment erosion is one of the most notorious phenomenon damaging the turbines, in the Himalayan region. Francis turbine, which is one of the most used type of hydro turbine in the world as well as in Nepal, is affected quite severely, more so when operated in off design conditions. This study has taken a reference design of a Francis turbine from a hydropower in Nepal to optimize it for operation in variable speeds. Minimization of sediment erosion and maximization of efficiency are taken as the objective functions of the optimization, for which blade angles at trailing edge and blade angle distribution are taken as the design variables. The design space of the runner are constrained such that the optimized design could replace the existing runner in the turbine. Latin Hypercube Sampling technique is used to populate the design space such that the design variables are divided randomly to create required number of designs in the design space. Computational Fluid Dynamic analysis are performed on simplified numerical models of the samples to predict their performance and Sediment Erosion Rate Density (SERD), under various operating conditions. The results of output parameters, obtained from CFD, along with the design variables, are used to develop an approximation model relating the objective functions with the design parameters. NSGA-II optimization technique is used to search for the optimum design. The paper presents the comparison of the sediment erosion and efficiency of the reference runner and optimized runners under various operating conditions. It also presents an outline of the process used to optimize the runner for variable speed operation with minimum sediment erosion.

Cutting Mechanical Properties of Pumpkin Grafted Seedling Investigated by Finite Element Simulation and Experiment

The cutting device in the seedling grafting process was studied, which provided a reference for optimizing the structural parameters and working parameters of important shearing components in the seedling grafting line, thereby improving the performance of the cutting device. The dynamic cutting process of the cutting device was numerically simulated. The effects of four factors, the average cutting speed (X1), the sliding angle (X2), the cutting edge angle (X3), and the cutter clearance (X4) on the cutting force, were studied. The optimal combination of structural parameters and working parameters of the cutting device was determined. The simulation results showed that the sliding angle (X2) and the cutting edge angle (X3) affect the ultimate cutting stress. The average cutting speed (X1) and the cutter clearance (X4) affect the ultimate cutting force. When X1, X2, X3, and X4 are 579 mm/s, 39°, 25°, and 1.4 mm, respectively, it is the better combination parameter, and the ultimate cutting equivalent stress of the cutting device is 0.32 Mpa. A high-speed cutting device for grafted seedlings was built, and the cutting experiment was carried out. The experiment results showed that the simulated values fit well with the experimental data. Under the optimal combination of cutting parameters, the cutting stress of the cutting device was smaller. The finite element simulation of the seedling grafting cutting device reduces the experiment cost and provides a reference for developing the seedling grafting line.

Male Gender and Competitive Athlete Status Are Associated With Better Outcomes Following Hip Arthroscopy In Patients With Global Acetabular Retroversion

PurposeTo evaluate outcomes of hip arthroscopy in patients with global acetabular retroversion and to identify correlations between sex, radiographic measurements, athlete status, and return to play with patient-reported outcomes (PROs).MethodsRetrospective study of patients with global acetabular retroversion who underwent arthroscopic femoroacetabular impingement (FAI) surgery was performed. Global acetabular retroversion was defined by 3 criteria: the crossover sign, ischial spine sign, and posterior wall sign on an anteroposterior (AP) pelvic radiograph. Radiographs were used to measure lateral center edge angle, alpha angle, and anterior and posterior wall indices. Femoral version was measured with 3-dimensional computed tomography. Demographics included age, gender, athlete status, return to play, and reoperation. PROs included modified Harris Hip Score, Hip Outcome Score (HOS), Hip Disability and Osteoarthritis Outcome Score, visual analog scale (VAS), and Veterans RAND-12. Spearman correlation determined correlation with perioperative PROs. Generalized estimating equation determined independent predictors. Significance was set at P = .05.ResultsFrom 2013 to 2019, 149 patients (65.0% female) with 160 hips with FAI and global acetabular retroversion underwent hip arthroscopy. Follow-up averaged 29.6 months. All PROs demonstrated significant improvement with the exception of the Veterans RAND-12 Mental. Female patients scored significantly lower on most postoperative PROs and had greater VAS scores (P = .0002-0.0402). A greater proportion of male subjects met the minimum clinically important difference for the modified Harris Hip Score (88.00% vs 78.79%) Low femoral version correlated with greater HOS ADL, HOS Sport, and Hip Disability and Osteoarthritis Outcome Score Sport scores (P = .0077-0.0177). Athletes reported lower preoperative VAS scores, and higher perioperative scores in multiple PROs (P = .0004-0.0486). Nine hips (5.63%) underwent reoperation.ConclusionsPatients with global acetabular retroversion and FAI undergoing hip arthroscopy report good outcomes at short-term follow-up. Male subjects and athletes had superior outcomes compared to female subjects and nonathletes. Radiographic measurements did not correlate with outcomes with exception of low femoral version. Athletes reported lower preoperative pain scores and greater postoperative PROs than nonathletes.Level of EvidenceLevel IV, therapeutic case series.

An Updated Review of Femoroacetabular Impingement Syndrome.

Femoroacetabular impingement (FAI) is a chronic hip condition caused by femoral head and acetabular malformations resulting in abnormal contact across the joint. FAI often leads to labral, cartilaginous, and tissue damage that predispose this patient population to early osteoarthritis (OA). There are a variety of factors that increase the risk for FAI including younger age, Caucasian background, familial FAIS morphology, and competing in high-intensity sports during adolescence. Slow-onset, persistent groin pain is the most frequent initial presenting symptom. On physical examination, patients will typically have a positive FADIR test (flexion, adduction, internal rotation), also known as a positive impingement sign. FAI syndrome can be organized into three classifications; cam, pincer, or mixed. This classification refers to the characteristic morphological changes of the bony structures. The primary imaging modality for diagnosing FAI is a plain radiograph of the pelvis, which can be used to measure the alpha angle and the lateral center edge angle used to quantify severity. Conservative treatment is typically considered first-line treatment for mild to moderate FAI syndrome; however, the outcomes following postoperative surgical intervention have demonstrated excellent results. The most common surgical treatment option for FAI is done arthroscopically.

Generation mechanism of surface micro-texture in axial ultrasonic vibration-assisted milling (AUVAM)

Although axial ultrasonic vibration-assisted milling (AUVAM) is promising for rapid and economical fabrication of 3D micro-texture on various surfaces, it has been a challenge to obtain micro-texture with small feature size and large height simultaneously. The mechanism and major influence factors for the formation of micro-texture by this method were explored in this study. It was found that the generation of micro-texture was mainly caused by cutting and extrusion from the flank face of the milling tool under ultrasonic vibration. Therefore, a novel 3D tool model that considered the relief angle, end cutting edge angle and the blade profile was established in simulation analysis. The good agreement between simulation and experimental results demonstrated that the influence of the flank face on the micro-texture was mainly attributed to the relief angle of the milling tool. It was the first time to report that both the height and the profile shape of the micro-texture unit were affected by the overlap and extrusion between the flank surface and the micro-texture. But this influence diminished with the increase of spindle speed. 3D sinusoid-shaped micro-texture with minimum width of 20 μm and height of 2 μm (fully reproduced the ultrasonic amplitude) was realized with the relief angle of 40° and spindle speed of 4000 rpm. Other typical textures of weave, shell, scale and corrugation were also presented to show the effective regulation of texture patterns in AUVAM. This work provides both theoretical and practical basis for such a low-cost, efficient and controllable 3D micro-texture preparation method.