Roof Angle Research Articles

Distal Femoral Morphology is Altered in Skeletally Immature Anterior Cruciate Ligament (ACL)Injured Knees

Objectives:With an increased incidence of anterior cruciate ligament (ACL) injuries and high rates of re-injury among skeletally immature individuals, investigators have attempted to identify factors that may help risk stratify patients and provide families with prognostic data concerning the risk of re-injury. Osseous morphology of the tibia as described by posterior tibial slope has received attention as a possible risk factor for ACL injury. The purpose of this study is to describe distal femoral morphology in skeletally immature, ACL-injured patients and compare that to age-matched, uninjured individuals. The authors hypothesize that the distal femoral morphology in ACL injured knees differs significantly from that of age-matched normal knees.Methods:A retrospective radiographic review of 58 skeletally immature patients treated at a single institution was conducted. Patients were grouped by age with Group A =>12 years and Group B =13+ years. The Blumensaat Epiphyseal Containment of the Knee (BECK) Angle, which assesses the flexion of Blumensaat’s line relative to the distal femoral physis, was measured on the involved knee for each patient on standard lateral knee radiographs. Posterior tibial slope was also measured on lateral radiographs. (Figure 1) Roof angle and posterior tibial slope of the lateral plateau were measured on sagittal T1 magnetic resonance imaging sequences of the involved knee. Paired T-tests compared distal femoral morphology in ACL injured knees to the morphology of uninjured knees.Results:Patients in Group A had a significantly decreased mean BECK Angle compared to Group B patients (48° ± 1.87° vs 53.4° ± 6.69°; p=0.045). When comparing Group B to age-matched patients without ACL injuries, there was a significant increase in BECK Angle values found in those with ACL injuries. (53.4° ± 6.69° compared to 48.8° ± 5.9°; p=0.009). Group A patients also tended to have higher BECK Angles compared to their uninjured counterparts, though this did not reach statistical significance (48° ± 1.87° compared to 45.8° ± 5.3°; p=0.38). Conversely, Notch Roof Angle showed significantly increased values in Group A compared to Group B (44 ± 1.581° vs. 41.85° ± 6.347°; p=0.01). Females with ACL injuries showed significantly higher BECK Angle measurements compared to males across both groups (54.56° ± 6.599° vs. 50.84° ± 6.074°; p=0.002). Posterior tibial slope of the lateral plateau on MRI showed a significantly decreased mean value in females compared to males (5.57° ± 3.532° vs 6° ± 3.536°; p=0.051).Conclusion:Distal femoral morphology appears to change with age and differ between females and males. Skeletally immature individuals, who have sustained an ACL injury, have significantly different morphology of the distal femur when compared to age-matched patients without ACL injuries. When risk stratifying patients for first time or repeat ACL injury, assessment of the distal femoral BECK Angle can add valuable information.

Innovations in greenhouse systems – energy conservation by system design, sensors and decision support systems

The targets for energy saving in Dutch horticulture are high. Research follows the two lines: total energy reduction and sustainability. The principles for that are: maximum use of natural sunlight (free energy input to greenhouse, free light for crop growth and production); maximum insulation (prevent energy losses through greenhouse covering); efficient use of energy (e.g. next generation cultivation strategies, mechanical dehumidification, diffuse light, optimum CO2, low temperature heating, high humidity levels); replace fossil fuels by renewable energy sources (e.g. geothermal, biofuels, solar energy, wind). Research results are shown in the Innovation and Demo Centre for Energy in Bleiswijk (IDC Energy). The goal of this paper is to describe some of the newest results of the Dutch research programme on energy saving focussing on energy conservation by greenhouse system design and the use of sensors and decision support systems. Energy savings on heating of 50-70% have been realised for a tomato crop compared to average practice in a highly insulated greenhouse. Another greenhouse concept focusses on the maximum use of natural sunlight during low solar elevation. With 3D ray-tracing models the effect of greenhouse roof angle, orientation, shape and construction materials as well as the effect of different diffuse coverings with anti-reflective coatings and hydrophilic condensation properties on light transmission during winter months has been quantified. It is expected to gain 10-20% more natural light by the new greenhouse concept during winter months. Wireless sensors are used to measure temperature and humidity distribution at many spots inside a greenhouse. Innovative web-based decision support models have been introduced into practice to give insight in the climate distribution and to predict the risk for crop health. For that a new climate control strategy the Roaming Climate Measuring Box and a Botrytis Alert have been developed. The greenhouse climate is automatically controlled on basis of the most humid or coldest spot in the greenhouse. That way up to 10% of energy can be saved and the risk for botrytis can be minimised. Two new sensors measuring actual crop photosynthesis have been developed and are currently tested in practice. Sensors are based on (i) the CO2 balance of the greenhouse and (ii) measuring chlorophyll fluorescence of a crop by means of laser and camera technology. In the future, such information is envisaged to be directly used for greenhouse climate control or crop management.

Radiologic assessment of femoral and tibial tunnel placement based on anatomic landmarks in arthroscopic single bundle anterior cruciate ligament reconstruction.

Background:Accurate tibial and femoral tunnel placement has a significant effect on outcomes after anterior cruciate ligament reconstruction (ACLR). Postoperative radiographs provide a reliable and valid way for the assessment of anatomical tunnel placement after ACLR. The aim of this study was to examine the radiographic location of tibial and femoral tunnels in patients who underwent arthroscopic ACLR using anatomic landmarks. Patients who underwent arthroscopic ACLR from January 2014 to March 2016 were included in this retrospective cohort study.Materials and Methods:45 patients who underwent arthroscopic ACLR, postoperative radiographs were studied. Femoral and tibial tunnel positions on sagittal and coronal radiographic views, graft impingement, and femoral roof angle were measured. Radiological parameters were summarized as mean ± standard deviation and proportions as applicable. Interobserver agreement was measured using intraclass correlation coefficient.Results:The position of the tibial tunnel was found to be at an average of 35.1% ± 7.4% posterior from the anterior edge of the tibia. The femoral tunnel was found at an average of 30% ± 1% anterior to the posterior femoral cortex along the Blumensaat's line. Radiographic impingement was found in 34% of the patients. The roof angle averaged 34.3° ± 4.3°. The position of the tibial tunnel was found at an average of 44.16% ± 3.98% from the medial edge of the tibial plateau. The coronal tibial tunnel angle averaged 67.5° ± 8.9°. The coronal angle of the femoral tunnel averaged 41.9° ± 8.5°.Conclusions:The femoral and tibial tunnel placements correlated well with anatomic landmarks except for radiographic impingement which was present in 34% of the patients.

Orientation changes in the cruciate ligaments of the knee during skeletal growth: A porcine model.

Musculoskeletal injuries in pediatric patients are on the rise, including significant increases in anterior cruciate ligament (ACL) injuries. Previous studies have found major anatomical changes during skeletal growth in the soft tissues of the knee. Specifically, the ACL and the posterior cruciate ligament (PCL) change in their relative orientation to the tibial plateau throughout growth. In order to develop age-specific treatments for ACL injuries, the purpose of this study was to characterize orientation changes in the cruciate ligaments of the Yorkshire pig, a common pre-clinical model, during skeletal growth in order to verify the applicability of this model for pediatric musculoskeletal studies. Hind limbs were isolated from female Yorkshire pigs ranging in age from newborn to late adolescence and were then imaged using high field strength magnetic resonance imaging. Orientation changes were quantified from the magnetic resonance images using image segmentation software. Statistically significant increases were found in the coronal and sagittal angles of the ACL relative to the tibial plateau during pre-adolescent growth. Additional changes were observed in the PCL angle, Blumensaat angle, intercondylar roof angle, and the aspect ratio of the intercondylar notch. Only the sagittal angle of the ACL relative to the tibial plateau experienced statistically significant changes through late adolescence. The age-dependent properties of the ACL and PCL in the female pig mirrored results found in female human patients, suggesting that the porcine model may provide a pre-clinical platform to study the cruciate ligaments during skeletal growth. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2725-2732, 2017.

The effect of tail geometry on the slipstream and unsteady wake structure of high-speed trains

The effect of varying the roof-angle of the tail of a generic high-speed train on the unsteady wake structure and corresponding slipstream is investigated in a 1/10th scale wind-tunnel experiment. Insight into the slipstream and unsteady flow features are gained from 4-hole dynamic pressure probe measurements, surface-flow visualisations, measurements from a two-dimensional array of total pressure probes, and frequency analysis. The results show that increasing tail roof angle leads to a transition from an unsteady wake with a pair of streamwise vortices that exhibit sinusoidal, antisymmetric motion to an unsteady wake dominated by large-scale separation with vortex shedding from the sides of the train. It is the interaction of the streamwise vortices with vortex shedding from the sides that results in the widest unsteady wake, and consequently, the largest slipstream velocities.

Experimental and numerical study of the impact of the collector roof inclination on the performance of a solar chimney power plant

The solar chimney power plant (SCPP) is a promising solution to produce electrical power from solar energy. The optimization of the solar setup geometry is required to enhance its performance. In this paper, a numerical study is presented to evaluate the performance of the solar chimney power plants while varying the collector roof angle. The considered system is defined by the collector height equal to h=50mm, the chimney diameter equal to d=160mm, the collector diameter equal to D=2750mm and the chimney height equal to H=3000mm. Four collector roof angles, equal to β=−1.5°, β=−1°, β=0° and β=1°, were investigated. For each collector roof angle, the distribution of the magnitude velocity, the air temperature, the pressure, the incident radiation and the turbulence characteristics were presented and discussed. The efficient choice of the optimal geometry is based on the calculation of the maximum value of the air velocity within the SCPP. Results indicate that a negative collector-roof positively increases the air velocity. The obtained results present an interesting data which can provide the thermal characteristics of the air flow for the designers and the engineers to improve the overall efficiency of the solar setup.

Amelioration of Thermal Stress using Modified Roof in Dairy Animals under Tropics: A Review

Roof is an integral part of housing systems, which protects animals from solar radiation and rain water. During summer months, heat stress affects animal production adversely. Housing design and shade material play an important role in the microclimate modification and reduction of radiant heat load inside the shed. The most commonly used roofing materials include asbestos sheets, thatch, clay tiles, reinforced cement concrete, galvanized iron sheets, plastic sheets etc., which possess some merits as well as drawbacks. Ideal roof material should have high reflectivity, low conductivity, low under-surface emissivity besides being light, strong, durable, waterproof, good looking, free from tendency to condense moisture inside and economical. Since, animal houses are permanent structure in large organized dairy farms which cannot be changed frequently. Thus, it is worth giving to modify existing roof rather changing the whole structure, which can be achieved by roof modifications such as thermal insulation, polythene shade cloth or Agro-net, mud plastering, thatched asbestos roof, green roofs, roof paints, evaporative roof cooling, solar panels, etc. Effectiveness of roof may further be improved by using techniques of adjustment of roof height, eave length and angle of eave in years to come. A holistic approach which includes animal nutrition as well as animal genetics in addition to shelter management would be more promising in amelioration of heat stress of dairy animals in tropics.

Radiological Evaluation of Hip in Cerebral Palsy: A Randomized Cross-sectional Study

ABSTRACTIntroductionThe incidence of hip abnormalities in cerebral palsy (CP) patients has been reported as low as 2.6% and as high as 28%. Hip displacement is the second most common deformity after equines. The objective of this study is to evaluate the radiological changes of hip in CP for detecting early features of hip instability.Materials and methodsA total of 91 hips of 52 patients with CP who attended for rehabilitation management were randomly selected for the study. Hip surveillance was done in those cases where the clinical evaluation alone could not access stability. All the selected cases were evaluated radiologically with respect to acetabular angle, neck-shaft angles, degree of subluxation (migration percentage) and shape of femoral head.Results38 hips showed grade I, 14 hips grade II, 6 hips grade III, and 2 hips grade IV stage of migration percentage. Flattening of femoral head was laterally seen in 16 cases, both medial and lateral flattening was seen in 8 cases of subluxated hip. Acetabular roof angle was increased in cases with grade III and IV migration percentage. Acetabular angle was within 12 to 75° with mean angle of 32°. The mean true neck-shaft angle was 145.5° ranging from 134° to 170°ConclusionEarly detection of hip instability in Cerebral Palsy helps in timely intervention and that reduces or delays need for reconstructive surgery.How to cite this articleSahoo PK, Sahu MM, Chitapure T, Das SP. Radiological Evaluation of Hip in Cerebral Palsy: A Randomized Cross-sectional Study. Indian J Phy Med Rehab 2017;28(3):95-99.

Improving paranasal sinus computed tomography reporting prior to functional endoscopic sinus surgery – an ENT-UK panel perspective

Functional endoscopic sinus surgery is recognised to have a significant complication profile (e.g. blindness, cerebrospinal fluid leak and intracranial sepsis). Pre-operative computed tomography imaging is considered mandatory for surgical planning to reduce intra-operative risk. A radiological report is the 'gold standard' in image interpretation; however, because of a lack of otolaryngological or radiological guidance, its contents may be variable. By surveying practising otolaryngologists, this study aimed to provide some guidance which may be used by radiologists to produce more surgically relevant radiological reports. A prospective questionnaire was distributed to the ENT-UK panel. A total of 117 consultant members of the panel completed the survey. Twenty-nine per cent indicated that they were uncomfortable interpreting all areas of the computed tomography scan. Greatest importance was given to areas including the ethmoid roof (dehiscence, asymmetry and angle), lamina papyracea (dehiscence) and sphenoid sinus (carotid canal dehiscence and optic nerve relationships). Functional endoscopic sinus surgery is commonly performed by non-subspecialist rhinologists. The information obtained from this study can be used by radiologists to improve report relevance, particularly for the generalist ENT surgeon. This contributes to improving patient safety and helps avoid medicolegal litigation when complications arise.

Numerical analysis on thermal performance of a PCM-filled double glazing roof

Phase change material (PCM) applied in the glazing roof can decrease building energy consumption and improve thermal comfort by enhancing its thermal energy storage capacity. In the present work, thermal performance of a PCM-filled double glazing roof with different thickness of phase change material was numerically investigated on two groups of extinction coefficients of solid and liquid PCM, and the effect of the semi-transparent property of the glazing roof and zenith angle on the thermal performance was also studied. The results show that the semi-transparent property and zenith angle have a big effect on the thermal performance, including temperature time lag, total transmitted energy and transmitted solar energy. With PCM thickness increasing, the temperature time lag increases. However PCM thickness effect on total transmitted energy and transmitted solar energy is different in different time, which has a big effect on total transmitted energy mainly at 0:00–14:30 and 20:00–24:00, and has a violent effect on transmitted solar energy and solar transmittance mainly at 5:00–11:00. When the extinction coefficients of PCM increase, PCM thickness effect on thermal performance parameters turns bigger except for the temperature time lag.

Rotational Acetabular Osteotomy for Pre- and Early Osteoarthritis Secondary to Dysplasia Provides Durable Results at 20Years.

Hip dysplasia is a common cause of secondary osteoarthritis (OA). Periacetabular osteotomy or rotational acetabular osteotomy has been used as joint-preserving procedures. However, only a few reports of long-term results with these operations have been reported. (1) Would satisfactory clinical and radiographic outcomes be maintained at a mean duration of 20 years after rotational acetabular osteotomy for pre- and early-stage OA; and (2) could we identify risk factors for radiographic progression of OA? Between 1987 and 2001, we treated 159 patients (173 hips) with rotational acetabular osteotomies for the diagnosis of pre-OA or early-stage OA according to the technique of Ninomiya and Tagawa. During that period, our general indications for this approach were age younger than 60 years, center-edge angle less than 20°, and improved femoral head coverage and joint congruency on preoperative AP plain radiographs of the hip in abduction; we did not use this approach when joint congruency was not improved or no widening of the joint space was noted on preoperative AP plain radiographs of the hip in abduction. Of those patients, 21 patients with pre-OA (followup rate: 84% [27 hips]) and 110 patients in the early-stage group (followup rate: 82% [118 hips]) were available at a minimum of 15 years for a total patient group of 131 (followup rate: 82% [145 hips]). The mean age at the time of surgery was 22 years in the pre-OA group and 38 years in the early-stage group. The mean followup was 21 years in the pre-OA group and 20 years in the early-stage group. Clinical evaluation was performed with the Merle d'Aubigne and Postel rating scale, and radiographic analyses included measurements of the center-edge angle, acetabular roof angle, and head lateralization index on preoperative and postoperative AP radiographs of the pelvis. Postoperative joint congruency was also evaluated. The cumulative probabilities of radiographic signs of OA progression were estimated with use of the Kaplan-Meier product-limited method and parametric survivorship analysis using the Cox proportional-hazards model was used to determine risk factors for radiographic OA progression. The mean clinical score improved very slightly, from 15 (SD, 0.8) to 18 (SD, 1.1) (95% confidence interval [CI], -2.9 to -2.0; p < 0.001) in the pre-OA group and from 15 (SD, 1.0) to 16 (SD, 2.1) (95% CI, -2.0 to -1.2; p < 0.001) in the early-stage group at followup. Fourteen patients (15 hips) including one pre-OA patient (one hip) and 13 early-stage patients (14 hips) experienced worsening of their Merle d'Aubigne and Postel score, from a mean of 15 (SD, 0.9) to 12 (SD, 1.6) (95% CI, 1.8-3.3; p < 0.001). Eight patients (nine hips) with early-stage OA preoperatively underwent total hip arthroplasty at a mean duration after rotational acetabular osteotomy of 20 (SD, 2.5) years. Radiographic indices were improved after surgery in both groups. Radiographic progression of OA occurred in 24 patients (25 hips). Kaplan-Meier survivorship analysis, with radiographic signs of progression of OA as the endpoint, predicted survival of 96% (95% CI, 89%-100%) at 10 years and 20 years in the pre-OA group. For the early-stage group, we found survivorship of 89% (95% CI, 83%-95%) at 10 years and 78% (95% CI, 69%-87%) at 20 years. We identified two factors associated with poor outcome: fair (rather than excellent and good) postoperative joint congruency (hazard ratio, 12.1; 95% CI, 3.8-39; p < 0.001) and age older than 46 years at the time of surgery (hazard ratio, 4.6; 95% CI, 1.9-11; p < 0.01). Rotational acetabular osteotomy is an effective surgical procedure for symptomatic dysplastic hips in pre- and early-stage OA, and it prevented radiographic OA progression and maintained hip function at a mean 20 years after surgery. Level IV, therapeutic study.

Research on Passive Design Optimization about an Experimental Rural Residence in Hot Summer and Cold Winter Region of China

In China, rural residential environment under the poor construction measures has not been satisfactory due to the backward infrastructure of countryside and the lacking of professional planning, which will result in considerable amount of energy consumption in the future. The economy of rural residences in the hot summer and cold winter region of China is relative developed, but the indoor thermal environmental quality is not so good. In this paper, the design strategies directed by passive design ideas for a small experimental rural residential building located in Hangzhou city was introduced and researched in response to hot summer and cold winter climate. Through modeling solution undertaken by Ecotect software, the building performance was simulated and analyzed for the optimization of design factors, such as shape, roof angle, insulation system, shading devices, as well as day-lighting system. Based on the above study, a set of appropriate energy-saving technologies were provided for improving the new rural residences construction in Hangzhou, which should also be recommended to other projects constructed in the same climate region.

Decreased Lumbar Lordosis and Deficient Acetabular Coverage Are Risk Factors for Subchondral Insufficiency Fracture.

Subchondral insufficiency fracture (SIF) of the femoral head occurs in the elderly and recipients of organ transplantation. Osteoporosis and deficient lateral coverage of the acetabulum are known risk factors for SIF. There has been no study about relation between spinopelvic alignment and anterior acetabular coverage with SIF. We therefore asked whether a decrease of lumbar lordosis and a deficiency in the anterior acetabular coverage are risk factors. We investigated 37 patients with SIF. There were 33 women and 4 men, and their mean age was 71.5 years (59-85 years). These 37 patients were matched with 37 controls for gender, age, height, weight, body mass index and bone mineral density. We compared the lumbar lordosis, pelvic incidence, pelvic tilt, sacral slope, acetabular index, acetabular roof angle, acetabular head index, anterior center-edge angle and lateral center-edge angle. Lumbar lordosis, pelvic tilt, sacral slope, lateral center edge angle, anterior center edge angle, acetabular index and acetabular head index were significantly different between SIF group and control group. Lumbar lordosis (OR = 1.11), lateral center edge angle (OR = 1.30) and anterior center edge angle (OR = 1.27) had significant associations in multivariate analysis. Decreased lumbar lordosis and deficient anterior coverage of the acetabulum are risk factors for SIF as well as decreased lateral coverage of the acetabulum.

Assessment of Extreme Wind Risk for Window Systems in Apartment Buildings Based on Probabilistic Model

본 연구에서는 강풍 위험과 강풍 취약도의 합성곱을 통하여 강풍 위험도를 평가할 수 있는 확률적 체계를 수립하였으며, 수치적으로 개발한 모형으로 아파트 창호 시스템의 강풍 위험도를 평가하였다. 강풍 위험 모형은 1951년부터 2013년까지에 한반도에 영향을 준 태풍의 기후학적 자료를 몬테카를로 모사기법에 적용하여 개발되었다. 또한 몬테카를로 모사기법으로 창호 시스템의 저항성능과 풍하중의 확률 분포를 비교하여 강풍에 대한 4가지 피해단계의 구조적 파괴확률을 평가할 수 있는 취약도 모형이 개발되었다. 개발된 몬테카를로 모사기법으로 평가한 강풍 위험과 강풍 취약도는 각각 웨이블 분포와 로그정규분포로 곡선맞춤 되었으며, 합성곱을 통한 강풍 위험도 평가에 사용되었다. 본 연구에서 개발한 확률적 위험도 평가 체계를 통하여 평가지역, 지표조도, 지형, 지붕 경사각, 건물 높이 등이 아파트 창호 시스템의 강풍 위험도에 미치는 영향성을 정량적으로 평가할 수 있었다. 향후 본 연구를 통하여 개발된 강풍 위험도 평가 모델은 평가지역의 존재하는 건축물에 대한 데이터베이스와 결합하여 손실추정 및 피해 저감대책 수립 등의 분야에서 활용이 가능할 것으로 판단된다.In this study, a coupled probabilistic framework is developed to assess wind risk on apartment buildings by using the convolution of wind hazard and fragility functions. In this framework, typhoon induced extreme wind is estimated by applying the developed Monte Carlo simulation model to the climatological data of typhoons affecting Korean peninsular from 1951 to 2013. The Monte Carlo simulation technique is also used to assess wind fragility function for 4 different damage states by comparing the probability distributions of the window system’s resistance performance and wind load. Wind hazard and fragility functions are modeled by the Weibull and lognormal probability distributions based on simulated wind speeds and failure probabilities. The modeled functions are convoluted to obtain the wind risk for the different damage levels. The developed probabilistic framework clearly shows that wind risk are influenced by various important characteristics of terrain and apartment building such as location of building, exposure category, topographic condition, roof angle, height of building, etc. The risk model presented in this paper can be used as tools to predict economic loss estimation and to establish wind risk mitigation plan for the existing building inventory.

Surgical Treatment of Adolescent Acetabular Dysplasia With a Periacetabular Osteotomy: Does Obesity Increase the Risk of Complications?

The Bernese periacetabular osteotomy (PAO) is frequently used to treat symptomatic acetabular dysplasia in the adolescent age group. Despite encouraging results, factors predictive of the development of postoperative complications remain poorly understood. The purpose of this study was to investigate whether obesity is a risk factor for complications following PAO in adolescents. A retrospective cohort study design was used to collect data from 3 different institutions. Children and adolescents (below 19 y of age) who underwent PAO and were followed for minimum of 12 months were included. Obesity was defined as a body mass index ≥95 percentile. The modified Clavien-Dindo classification was used to grade complications. A logistic regression analysis was used to identify factors related to the development of a complication that required treatment outside of routine postoperative care (complication grades II to V). Changes in radiographic parameters including Tönnis acetabular roof angle, anterior center-edge angle, and lateral center-edge angle among obese versus nonobese subjects were also evaluated. The mean age at surgery among the 84 adolescents included in the study was 16.5 years (range, 12 to 19 y). A total of 11% of the population was considered obese. Obesity (P=0.0047) was the only variable significantly associated with the development of a complication. After controlling for study site, the odds of an obese subject developing a complication were 10 [95% confidence interval (CI), 1.89-59.8] times the odds of a nonobese subject developing a complication. There was no difference in the magnitude of change in anterior center-edge angle (P=0.1251), lateral center-edge angle (P=0.9774), or Tönnis (P=0.5770) angular correction that was achieved among the obese versus nonobese subjects following surgery. The Bernese PAO allows for adequate radiographic correction of acetabular dysplasia among obese and nonobese adolescents. However, the hip preservation surgeon should be aware of the higher risk of complications among obese adolescents undergoing PAO for the treatment of symptomatic acetabular dysplasia. Level III-retrospective study.

Hip Arthroscopy: Where We Are, and Where We Are Going.

Hip Arthroscopy: Where We Are, and Where We Are Going.

Effects of rotational acetabular osteotomy on the mechanical stress within the hip joint in patients with developmental dysplasia of the hip: a subject-specific finite element analysis.

In this study we used subject-specific finite element analysis to investigate the mechanical effects of rotational acetabular osteotomy (RAO) on the hip joint and analysed the correlation between various radiological measurements and mechanical stress in the hip joint. We evaluated 13 hips in 12 patients (two men and ten women, mean age at surgery 32.0 years; 19 to 46) with developmental dysplasia of the hip (DDH) who were treated by RAO. Subject-specific finite element models were constructed from CT data. The centre-edge (CE) angle, acetabular head index (AHI), acetabular angle and acetabular roof angle (ARA) were measured on anteroposterior pelvic radiographs taken before and after RAO. The relationship between equivalent stress in the hip joint and radiological measurements was analysed. The equivalent stress in the acetabulum decreased from 4.1 MPa (2.7 to 6.5) pre-operatively to 2.8 MPa (1.8 to 3.6) post-operatively (p < 0.01). There was a moderate correlation between equivalent stress in the acetabulum and the radiological measurements: CE angle (R = -0.645, p < 0.01); AHI (R = -0.603, p < 0.01); acetabular angle (R = 0.484, p = 0.02); and ARA (R = 0.572, p < 0.01). The equivalent stress in the acetabulum of patients with DDH decreased after RAO. Correction of the CE angle, AHI and ARA was considered to be important in reducing the mechanical stress in the hip joint.

The analysis on the impact of the roof angle on electricity energy generation of photovoltaic panels in Kahramanmaras, Turkey—A case study for all seasons

Photovoltaic (PV) panels absorb solar energy most when solar radiation perpendicularly reaches on upon surface. This leads to the notion of optimal roof angle. Optical and geometrical properties of the panels are of vital importance in order to obtain maximum energy from the Sun. Therefore, this study focuses on the horizontal roof angle which has a crucial impact on the performance of PV panels. Total solar radiation, optimal roof angle and effects of different angles on PV panels in Kahramanmaras province of Turkey on different days are numerically and experimentally analyzed and discussed. Additionally, roof angle influences the amount of solar radiation reaching on the surface and varies depending on the geographic location and seasons. 7.9% more energy can be generated in the proposed systems where roof angle can be daily adjusted. This greatly influences the amount of solar energy when optimal roof angles are calculated annually depending on the seasons in a region. However, it is quite costly and challenging to adjust the roof angle as far as a building is concerned.

Relationship between developmental dislocation of the hip in infant and acetabular dysplasia at skeletal maturity.

Previous reports demonstrated 8–60% patients treated for developmental dislocation of hip (DDH) in infancy have residual acetabular dysplasia (AD) at skeletal maturity. AD patients reportedly exhibit abnormal morphology of the pelvis, high rates of comorbid spinal congenital anomalies and high bone mineral density. These physical findings suggest that AD patients have genetic background. We examined the percentage of AD patients with hip pain at skeletal maturity having a history of DDH in infancy and the correlation between the severity of AD at skeletal maturity and history of DDH treatment to investigate the relationship between AD and DDH.A total of 245 patients were radiographically examined for any history of DDH treatment in infancy. The study included 226 women and 19 men with a mean age at examination of 40.7 years (range 17–59 years).Eighty-eight patients (36%) had a history of DDH treatment (DDH group) and the remaining 157 patients (64%) had no history of DDH treatment (non-DDH group). The average age was lower and acetabular angle was larger in the DDH group. There was a significant increasing trend of the percentage of DDH patients associated with the severity of AD classified with CE, acetabular angle, and acetabular roof angle.Our data suggest that there are several AD patients without a history of DDH in Japan, and AD in patients without a history of DDH has different characteristics from AD in patients with a history of DDH.

CFD analysis of cross-ventilation of a generic isolated building with asymmetric opening positions: Impact of roof angle and opening location

The position of window openings and roof inclination are important parameters determining the effectiveness of wind-driven cross-ventilation in buildings. Many studies on natural ventilation have been performed in the past, however, a detailed review of the literature indicates that the majority of these studies focused on flat roofs with symmetric opening positions. There is a lack of research that analyzes the impact of asymmetric opening positions and roof inclination on natural ventilation potential. This paper presents Computational Fluid Dynamics (CFD) simulations to analyze the natural ventilation flow in a generic isolated building with different vertical positions of the outlet opening – yielding asymmetric opening positions – and five different roof inclination angles. The simulations are performed using the 3D steady Reynolds-Averaged Navier–Stokes (RANS) equations. They are based on a grid-sensitivity analysis and on validation with previously published wind-tunnel measurements using Particle Image Velocimetry. The results show that the shear-stress transport (SST) k-ω and the Renormalization-group (RNG) k-ε turbulence models provide the best agreement with the experimental data. It is also shown that the roof inclination angle has a significant effect on the ventilation flow; the volume flow rate increases by more than 22%. The maximum local indoor air velocity increases considerably when the inclination angle is increased, however, the differences in the average velocity in the occupied zone are only around 7%. The vertical position of the outlet opening has a relatively small impact on the volume flow rate (less than 4%), and a small influence on the average velocity in the occupied zone (<5%).