Quadrilateral plate fractures of the acetabulum:Classification,approach,implant therapy and related research progress

The quadrilateral plate(QP)is an essential structure of the inner wall of the acetabulum,an important weight-bearing joint of the human body,which is often involved in acetabular fractures.The operative exposure,reduction and fixation of QP fractures have always been the difficulties in orthopedics due to the special morphological structure and anatomical features of the QP.Fortunately,there have been many effective methods and instruments developed for QP exposure,reduction and fixation by virtue of the combined efforts of numerous orthopedists.At the same time,each method presents with its own advantages and disadvantages,resulting in different prognoses.It is necessary to have a thorough understanding of the anatomy,radiology and fixation techniques of the QP in terms of patient prognosis optimization.In this paper,the anatomical features,definition and classification of QP,operative approach selection,implant internal fixation methods and efficacy were reviewed.

Using fracture-based continuum modeling of coupled geomechanical-hydrological processes for numerical simulation of hydraulic fracturing

This paper describes numerical simulation of hydraulic fracturing using fracture-based continuum modeling(FBCM)of coupled geomechanical-hydrological processes to evaluate a technique for high-density fracturing and fracture caging.The simulations are innovative because of modeling discrete fractures explicitly in continuum analysis.A key advantage of FBCM is that fracture initiation and propagation are modeled explicitly without changing the domain grid(i.e.no re-meshing).Further,multiple realizations of a preexisting fracture distribution can be analyzed using the same domain grid.The simulated hydraulic fracturing technique consists of pressurizing multiple wells simultaneously:initially without permeating fluids into the rock,to seed fractures uniformly and at high density in the wall rock of the wells;followed by fluid injection to propagate the seeded fracture density hydraulically.FBCM combines the ease of continuum modeling with the potential accuracy of modeling discrete fractures and fracturing explicitly.Fractures are modeled as piecewise planar based on intersections with domain elements;fracture geometry stored as continuum properties is used to calculate parameters needed to model individual fractures;and rock behavior is modeled through tensorial aggregation of the behavior of discrete fractures and unfractured rock.Simulations are presented for previously unfractured rock and for rock with preexisting fractures of horizontal,shallow-dipping,steeply dipping,or vertical orientation.Simulations of a single-well model are used to determine the pattern and spacing for a multiple-well design.The results illustrate high-density fracturing and fracture caging through simultaneous fluid injection in multiple wells:for previously unfractured rock or rock with preexisting shallow-dipping or horizontal fractures,and in situ vertical compressive stress greater than horizontal.If preexisting fractures are steeply dipping or vertical,and considering the same in situ stress condition,well pressurization without fluid permeation appears to be the only practical way to induce new fractures and contain fracturing within the target domain.

Precontoured buttress plate vs reconstruction plate for acetabulum posterior wall fractures: A biomechanical study

BACKGROUND The purpose of open reduction and internal fixation of acetabulum posterior wall fractures is to restore anatomical structure and stability of the hip joint, in order to start weight bearing as soon as possible and prevent hip arthrosis; restoration of the anatomy should preserve function of the joint as well. Although "special shaped precontoured plates" have been developed in recent years for surgical treatment of this region, studies comparing the traditional plates with the newly designed precontoured plates are lacking.AIM To evaluate the biomechanical properties of precontoured anatomic buttress and conventional curved reconstruction plates(CCRPs) for posterior wall acetabulum fracture treatment.METHODS Twelve pelvis models were created for testing plate treatment of fracture in the posterior wall of the acetabulum. These 12 pelvis models were used to create 24 hemipelvis models(experimental) by cutting from the sagittal plane and passing over the center of gravity, after which the posterior wall acetabular fractures(of similar type and size) were created. In these experimental models, the right acetabulum was fixed with a 5-hole CCRP, while the left was fixed with a precontoured anatomic buttress plate(PABP). Samples were placed through thetest device and were subjected to static load testing, with a constant testing velocity of 2 mm/min until the load reached 2.3 kN or the acetabular fixation failed. Dynamic tests were also performed with sinusoidal wave load, with a maximal load of 2.3 kN and a load ratio of 0.1.RESULTS The average stiffness values were 460.83 ± 95.47 N/mm for the PABP and 291.99± 118.58 N/mm for the 5-hole CCRP. The precontoured anatomic acetabulum buttress plates had significantly higher rigidity than the CCRPs(P = 0.022). There was a statistically significant difference between the unloaded and 2.3 kN-loaded values of AL(posterosuperior fracture line vertical to the ground surface) and CL(posteroinferior fracture line vertical to the ground surface) parameters for both the PABPs and the 5-hole CCRPs(P = 0.036 and P = 0.045, respectively).According to the static tests, the amount of total displacement was significantly less in the PABPs than in the CCRPs. Comparative analysis of the displacement in the BL(posterior wall fracture line horizontal to the ground) parameter yielded no statistically significant differences between the PABP and the 5-hole CCRPs(P= 0.261).CONCLUSION PABP provides more stable fixation in acetabulum posterior wall fractures than5-hole CCRP, allowing for proximal or distal fracture line screw application without reshaping.

Functional Outcomes of Traumatic Complex Acetabulum Fractures with Open Reduction and Internal Fixation: 200 Cases

Objective: Acetabular fractures are common injuries in Iran. We assess the functional outcome of open reduction and internal fixation management of displaced Complex acetabular fractures. Materials and Methods: We analyzed a case series of patients with open reduction and internal fixation (ORIF) for complex acetabular fractures. Two hundred patients (132 men, 68 women) in four age groups including with a mean age of 43.39 ± 6.18 years (range 20 - 59 years) and a mean follow-up of 82.34 ± 12.48 months (range 18 - 109 months) met the inclusion criteria. Functional outcome at final follow-up was graded assessed according to Harris score. Factors affecting were defined. Results: Anatomic reduction was achieved in 192 hips, imperfect in 8 and poor in none. Radiological outcome revealed excellent results in 128 (64%) hips, good in eight, fair in five and none in poor. Harris score were excellent in 139 (69.5%) hips, good in 43 (21.5%) and fair in 18 (9%) and poor in none. The anatomical reduction results had a favorable final functional outcome. (0.003) However, BMI (P Conclusion: Optimal functional and radiological outcomes have been achieved with anatomic postoperative reduction. Also experience of specialist, on time surgery and good recovery lead to receiving excellent functional outcome with at least complications.

Borehole stability in naturally fractured rocks with drilling mud intrusion and associated fracture strength weakening:A coupled DFN-DEM approach

Borehole instability in naturally fractured rocks poses significant challenges to drilling.Drilling mud invades the surrounding formations through natural fractures under the difference between the wellbore pressure(P w)and pore pressure(P p)during drilling,which may cause wellbore instability.However,the weakening of fracture strength due to mud intrusion is not considered in most existing borehole stability analyses,which may yield significant errors and misleading predictions.In addition,only limited factors were analyzed,and the fracture distribution was oversimplified.In this paper,the impacts of mud intrusion and associated fracture strength weakening on borehole stability in fractured rocks under both isotropic and anisotropic stress states are investigated using a coupled DEM(distinct element method)and DFN(discrete fracture network)method.It provides estimates of the effect of fracture strength weakening,wellbore pressure,in situ stresses,and sealing efficiency on borehole stability.The results show that mud intrusion and weakening of fracture strength can damage the borehole.This is demonstrated by the large displacement around the borehole,shear displacement on natural fractures,and the generation of fracture at shear limit.Mud intrusion reduces the shear strength of the fracture surface and leads to shear failure,which explains that the increase in mud weight may worsen borehole stability during overbalanced drilling in fractured formations.A higher in situ stress anisotropy exerts a significant influence on the mechanism of shear failure distribution around the wellbore.Moreover,the effect of sealing natural fractures on maintaining borehole stability is verified in this study,and the increase in sealing efficiency reduces the radial invasion distance of drilling mud.This study provides a directly quantitative prediction method of borehole instability in naturally fractured formations,which can consider the discrete fracture network,mud intrusion,and associated weakening of fracture strength.The information provided by the numerical approach(e.g.displacement around the borehole,shear displacement on fracture,and fracture at shear limit)is helpful for managing wellbore stability and designing wellbore-strengthening operations.

Management of geriatric acetabular fractures:Contemporary treatment strategies

Acetabular fractures in the geriatric population are typically low-energy fractures resulting from a fall from standing height.Compromised bone quality in the elderly,as well as this population’s concomitant medical comorbidities,render the management of such fractures challenging and controversial.Non-operative management remains the mainstay of treatment,although such a choice is associated with numerous and serious complications related to both the hip joint as well as the general condition of the patient.On the other hand,operatively treating acetabular fractures(e.g.,with osteosynthesis or total hip arthroplasty)is gaining popularity.Osteosynthesis can be performed with open reduction and internal fixation or with minimally invasive techniques.Total hip arthroplasty could be performed either in the acute phase combined with osteosynthesis or as a delayed procedure after a period of non-operative management or after failed osteosynthesis of the acetabulum.Regardless of the implemented treatment,orthogeriatric co-management is considered extremely crucial,and it is currently one of the pillars of a successful outcome after an acetabular fracture.

Epidemiologic investigation of pediatric distal humerus fractures: An American insurance claims database study

BACKGROUND Distal humerus elbow fractures are one of the most common traumatic fractures seen in pediatric patients and present as three main types:Supracondylar(SC),lateral condyle(LC),and medial epicondyle(ME)fractures.AIM To evaluate the epidemiology of pediatric distal humerus fractures(SC,LC,and ME)from an American insurance claims database.METHODS A retrospective review was performed on patients 17 years and younger with the ICD 9 and 10 codes for SC,LC and ME fractures based on the IBM Truven MarketScan®Commercial and IBM Truven MarketScan Medicare Supplemental databases.Patients from 2015 to 2020 were queried for treatments,patient age,sex,length of hospitalization,and comorbidities.RESULTS A total of 1133 SC,154 LC,and 124 ME fractures were identified.SC fractures had the highest percentage of operation at 83%,followed by LC(78%)and ME fractures(41%).Male patients were,on average,older than female patients for both SC and ME fractures.CONCLUSION In the insurance claims databases used,SC fractures were the most reported,followed by LC fractures,and finally ME fractures.Age was identified to be a factor for how a pediatric distal humerus fractures,with patients with SC and LC fractures being younger than those with ME fractures.The peak age per injury per sex was similar to reported historic central tendencies,despite reported trends for younger physiologic development.

Management and classification of the fracture of lateral process of talus:An overview and literature update

Fracture of the lateral process of the talus(FLPT)is uncommon in clinical practice and can be easily missed or misdiagnosed.In recent years,as researchers from all over the world have further deepened their research on FLPT,there has been a breakthrough in the classification,and the methods and principles of clinical management have changed accordingly;however,there is still no standardized guideline for the diagnosis and management of FLPT,and there have been few relevant literature review articles related to this kind of fracture in the past at least 5 years.In this article,we review the clinical classification,classification-based therapeutic recommendations,and prognosis of FLPT,with the aim of providing a reference for the clinical diagnosis and management of this infrequent fracture.

Assessing the readability of online information about jones fracture

BACKGROUND Hand in hand with technological advancements,treatment modalities continue to grow.With the turn of the century,the internet has become the number one source of information for almost every topic.Thus,many patients look toward the internet as their primary source of information to learn about their respective medical conditions.The American Medical Association and National Institute of Health strongly recommend that online medical information be written at the 6th to 8th-grade level to aid comprehension by patients of all literacy backgrounds.AIM To assess the readability of online information regarding Jones fracture.Our hypothesis is that the reading level of medical information published on websites far exceeds the recommended reading level of 6th-8th grade as proposed by the American Medical Associate and National Institute of Health.The result of this study can help us formulate improved recommendations for publishing more comprehensible material and,thus,eventually improve patient compliance and clinical outcomes.METHODS The exact phrase“Jones fracture”was queried on the three most common search engines,Google,Yahoo!,and Bing,on December 28,2022.As of December 2022,Google held 84%,Bing held 9%,and Yahoo!held 2%of the worldwide search engine market share.Web pages uniform resource locator from the first three pages of search results were recorded from each search engine.These web pages were classified according to academic,physician-sponsored,governmental and non-government organizations(NGO),commercial,and unspecified as per formally defined categories.Websites associated with an educational institution or medical organization were classified as academic.Websites with products for sale,corporate sponsorship,or advertisements were classified as commercial.Governmental websites or NGOs comprised those that received government subsidies or grants.Webpages that were independently owned by physicians or physician groups were respectively classed as physician sponsored.The remainder of websites that did not fall under the above categories were classified as unspecified.RESULTS A total of 93 websites were analyzed for reading assessment.A whopping 44%of websites were commercial,followed by 22%of physician-sponsored websites.Third place belonged to non-government organization websites holding a 15%share.The academic website held a meager 9%portion,while unspecified sites were 3%.The table illustrates mean readability scores,along with average cumulative grade level.The average grade level was 10.95±2.28 for all websites,with a range of 6.18 to 18.90.Since P values were more than 0.05,there was not a significant statistical difference between the first page results and the results of all pages.Thus,we can rationalize that readability scores are consistent throughout all pages of a website.CONCLUSION Hand in hand with technological advancements,treatment modalities continue to grow.With the turn of the century,the internet has become the number one source of information for almost every topic.Thus,many patients look towards the internet as the primary source of information to learn about their respective medical conditions.Our study demonstrates that current online medical information regarding Jones fracture is written at an extraordinarily high-grade level,with an average grade level of all websites at 10.95,nearly an 10th-grade educational level.The American Medical Association and National Institute of Health strongly recommend that online medical information should be written at the 6th to 8th-grade level to aid comprehension by patients of all literacy backgrounds.On the contrary,most of the medical information evaluated was at an 10th-grade level,which far exceeds recommendations by AMA and NIH.This is particularly relevant because readability scores are directly proportional to the level of comprehension attained by readers,thus directly impacting patient outcomes.In conclusion,we suggest and encourage that all online reading materials should be re-written at the 6th to 8th-grade level in a public service effort to increase compliance with treatment goals and raise awareness of preventive measures.

Visualization and characterization of experimental hydraulic fractures interacting with karst fracture-cavity distributions

Karst fracture-cavity carbonate reservoirs,in which natural cavities are connected by natural fractures to form cavity clusters in many circumstances,have become significant fields of oil and gas exploration and exploitation.Proppant fracturing is considered as the best method for exploiting carbonate reservoirs;however,previous studies primarily focused on the effects of individual types of geological formations,such as natural fractures or cavities,on fracture propagation.In this study,true-triaxial physical simulation experiments were systematically performed under four types of stress difference conditions after the accurate prefabrication of four types of different fracture-cavity distributions in artificial samples.Subsequently,the interaction mechanism between the hydraulic fractures and fracture-cavity structures was systematically analyzed in combination with the stress distribution,cross-sectional morphology of the main propagation path,and three-dimensional visualization of the overall fracture network.It was found that the propagation of hydraulic fractures near the cavity was inhibited by the stress concentration surrounding the cavity.In contrast,a natural fracture with a smaller approach angle(0°and 30°)around the cavity can alleviate the stress concentration and significantly facilitate the connection with the cavity.In addition,the hydraulic fracture crossed the natural fracture at the 45°approach angle and bypassed the cavity under higher stress difference conditions.A new stimulation effectiveness evaluation index was established based on the stimulated reservoir area(SRA),tortuosity of the hydraulic fractures(T),and connectivity index(CI)of the cavities.These findings provide new insights into the fracturing design of carbonate reservoirs.

Blood Calcium as a Protective Factor against Traumatic Fracture

Purpose: This study aims to investigate the predictive value of blood calcium in the prognosis of traumatic fracture. Methods: A retrospective experimental design was employed, 112 cases (52 non-fracture and 60 traumatic fracture) were randomly selected. The type of fracture complies with WHO-recommended (2019) diagnostic criteria for osteoporosis combined with fracture. The blood pressure (BP) was measured by OMRON’s HEM-7136 model electronic blood pressure monitor. Blood calcium (Ca2+), and blood phosphorus (P) values were measured using Colorimetric Roche kits on a Roche/Hitachi fully automated biochemical analyzer. Data collection and analysis followed. Results: Higher levels of age, systolic and diastolic blood pressures were found in the traumatic fracture group compared to the control group, whereas weight, height, and blood phosphorus did not differ significantly (P adjusting for age, systolic blood pressure, diastolic blood pressure, and blood phosphorus, binary logistic regression analysis revealed that blood calcium was a protective factor against traumatic fracture (β = -26.85, OR = 0.00, 95% CI = 0.00 -0.02, P = 0.022). Conclusion: The findings suggest that high and low blood calcium levels may serve as useful indicators in predicting the prognosis of fractures resulting from trauma.

Clinical outcomes of triceps reflecting anconeus pedicle and olecranon osteotomy approach for distal humerus intercondylar fractures

BACKGROUND The preferred treatment for distal humeral intercondylar fractures is open reduction and internal fixation.While there is consensus about the posterior approach,several posterior approaches have been developed.It is debatable as to which approach is best.AIM To compare triceps reflecting anconeus pedicle(TRAP)and olecranon osteotomy approaches for internal fixation of distal humeral intercondylar fracture.METHODS In total,40 cases of Arbeitsgemeinschaft für Osteosynthesefragen/Association of the Study of Internal Fixation type C,closed,and Gustilo type I intercondylar humeral fractures were included.Patients ranged in age from 18 years to 70 years.The patients were randomized into two groups:TRAP group and olecranon osteotomy group,with 20 cases in each.All were followed up at 6 wk,3 months,6 months,and 12 months.Functional outcomes were measured in terms of flexion-extension arc,Disabilities of Arm,Shoulder and Hand score,and Mayo Elbow Performance Score.RESULTS The mean age was 43.2 years in the TRAP group and 37.5 years in the olecranon osteotomy group.The mean operative time and mean duration of hospital stay in the TRAP group were significantly higher than in the olecranon osteotomy group(119.5 vs 111.5 min and 9.85 vs 5.45 d,respectively).The mean arc of flexion-extension,Disabilities of Arm,Shoulder and Hand score,and Mayo Elbow Performance Score were comparable without any significant difference in the groups at the 12-month follow-up(107.0 vs 106.2,18.3 vs 15.7,and 84.2 vs 86.2,respectively).Ulnar paresthesia and superficial infections were comparable in both groups(2 cases vs 3 cases and 3 cases vs 2 cases,respectively).Hardware prominence was significantly higher in the olecranon osteotomy group,mostly due to tension band wiring.CONCLUSION Both approaches were equivalent,but there is a need for further study including higher numbers of subjects and longer study duration to prove the benefits of one approach over the other.

Study on the Impact of Massive Refracturing on the Fracture Network in Tight Oil Reservoir Horizontal Wells

Class III tight oil reservoirs have low porosity and permeability,which are often responsible for low production rates and limited recovery.Extensive repeated fracturing is a well-known technique to fix some of these issues.With such methods,existing fractures are refractured,and/or new fractures are created to facilitate communication with natural fractures.This study explored how different refracturing methods affect horizontal well fracture networks,with a special focus on morphology and related fluid flow changes.In particular,the study relied on the unconventional fracture model(UFM).The evolution of fracture morphology and flow field after the initial fracturing were analyzed accordingly.The simulation results indicated that increased formation energy and reduced reservoir stress differences can promote fracture expansion.It was shown that the length of the fracture network,the width of the fracture network,and the complexity of the fracture can be improved,the oil drainage area can be increased,the distance of oil and gas seepage can be reduced,and the production of a single well can be significantly increased.

Axial load-share ratio testing to assess the healing of open tibial fractures treated with the Taylor Spatial Frame

Background:The Taylor Spatial Frame(TSF)has gained popularity among orthopedic surgeons for treating open fractures.However,a key challenge is the timely and safe removal of the frame.This study assessed the efficacy and safety of axial load-share ratio(ALSR)testing to evaluate callus healing strength after TSF treatment of open tibial fractures.Methods:A retrospective case-control study was conducted,analyzing 180 adult patients with open tibial fractures treated at Tianjin Hospital’s Orthopedic Limb Correction Unit between August 2019 and August 2022.All patients underwent TSF external fixation surgery,and were divided into two groups based on ALSR testing.Group I(92 patients)underwent ALSR testing,with frame removal if the test value fell below 5%.Traditional methods were used for fixator removal guidance in Group II(88 patients).Clinical outcomes,including fixation duration,complications after fixator removal,and Johner-Wruhs functional scores,were compared between the two groups.Results:The groups showed no statistically significant differences(P>0.05)in sex,age,injury side,body mass index,surgery timing,or fracture type.Group I had a significantly shorter fixation duration(25.85±5.57 weeks)compared to Group II(31.82±6.98 weeks)(P<0.05).Following fixator removal,Group I demonstrated superior Johner-Wruhs scores compared to Group II,indicating better outcomes(P<0.05).Complication rates did not differ significantly between the groups at the last follow-up(P>0.05).Conclusion:Regular postoperative ALSR testing could safely and effectively guide TSF removal following open tibial fracture treatment.This method significantly reduced fixation duration compared to traditional guidance methods while maintaining efficacy and safety.

Cemented vertebra and adjacent vertebra refractured in a chronic kidney disease-mineral and bone disorder patient: A case report

BACKGROUND Although percutaneous vertebral augmentation(PVA)is a commonly used procedure for treating vertebral compression fracture(VCF),the risk of vertebral refracture should be considered.Chronic kidney disease-mineral and bone disorder(CKD-MBD)is a systemic disease of mineral and bone metabolism.It is associated with an increased risk of fracture.Few studies have reported the use of PVA in patients with CKD-MBD.We herein report a rare case wherein the cemented vertebra and the adjacent vertebra refractured simultaneously in a CKD-MBD patient after PVA.CASE SUMMARY A 74-year-old man suffered from low back pain after taking a fall about 3 wk ago.According to physical examination,imaging and laboratory findings,diagnoses of T12 VCF,CKD-MBD,and chronic kidney disease stage 5 were established.He then received percutaneous vertebroplasty at T12 vertebra.Fourteen weeks later,he presented with T12 and L1 vertebral refractures caused by lumbar sprain.Once again,he was given PVA which was optimized for the refractured vertebrae.Although the short-term postoperative effect was satisfactory,he reported chronic low back pain again at the 3-month follow-up.CONCLUSION It is necessary that patients with CKD-MBD who have received PVA are aware of the adverse effects of CKD-MBD.It may increase the risk of vertebral refracture.Furthermore,the PVA surgical technique needs to be optimized according to the condition of the patient.The medium-and long-term effects of PVA remain uncertain in patients with CKD-MBD.

DICE:An open-source MATLAB application for quantification and parametrization of digital outcrop model-based fracture datasets

An open-source MATLAB application(app)named Discontinuity Intensity Calculator and Estimator(DICE)was developed in order to quantitatively characterize the fractures,or in more general,discontinuities within a rocky outcrop in three-dimensional(3D)digital data,such as digital outcrop model(DOM).The workflow proposed for the parametrization of the discontinuities consists of the following steps:(1)Analysis and mapping of the fractures detected within the 3D DOMs;(2)Calculation of the orientation,position and dimensions of discontinuities that are represented by best-fit circular planes;(3)Determining the discontinuity parameters(dimension,distribution,spacing and intensity)by the DICE algorithm using different 3D oriented sampling techniques(3D oriented scanline,3D oriented circular scan window and spherical scan volume).Different sampling methods were bench tested with a synthetic,as well as a natural case study,and compared in order to understand the advantages and limitations of each technique.The 3D oriented circular scan window appears to be the most effective method for fracture intensity estimation with high accuracy(error 0.4%)and stability with variations in scan radius.

FRACTURE序列在中轴型脊柱关节炎骶髂关节结构性病变中的诊断价值

目的:评估限制回波间隔的快速梯度回波类CT成像(FRACTURE)序列在检测中轴型脊柱关节炎(SpA)骶髂关节结构病变中的诊断价值。方法:回顾性分析83例确诊中轴型SpA患者在2021年12月-2022年8月进行骶髂关节MRI和CT检查的影像资料。评估图像包括FRACTURE、T_(1)WI序列和CT平扫图像。对骶髂关节的影像图像进行结构性病变评分:关节间隙变化(0~5分)、骨质侵蚀(0~3分)和骨质硬化(0~2分)。根据修改后的纽约标准评分系统对骶髂关节炎进行综合评分。结果:总共有166个骶髂关节图像(83名受试者)可供分析。以CT图像作为参考标准,FRACTURE序列在关节间隙改变、骨质侵蚀、骨质硬化和骶髂关节炎综合评分与CT结果表现出较高的一致性,AUC分别为0.908、0.943、0.918和0.944。与T_(1)WI相比,FRACTURE在关节间隙变化(91.8%vs.70.5%)、骨质侵蚀(93.3%vs.56.4%)、骨质硬化(94%vs.77.6%)和骶髂关节炎综合评分(98.9%vs.75.3%)方面具有更高的诊断准确性。结论:FRACTURE成像可以评估中轴型SpA患者骶髂关节的结构性病变,并显示出良好的诊断性能。

Complication rates after direct anterior vs posterior approach for hip hemiarthroplasty in elderly individuals with femoral neck fractures

BACKGROUND Dislocation rates after hemiarthroplasty reportedly vary from 1%to 17%.This serious complication is associated with increased morbidity and mortality rates.Approaches to this surgery are still debated,with no consensus regarding the superiority of any single approach.AIM To compare early postoperative complications after implementing the direct anterior and posterior approaches(PL)for hip hemiarthroplasty after femoral neck fractures.METHODS This is a comparative,retrospective,single-center cohort study conducted at a university hospital.Between March 2008 and December 2018,273 patients(a total of 280 hips)underwent bipolar hemiarthroplasties(n=280)for displaced femoral neck fractures using either the PL(n=171)or the minimally invasive direct anterior approach(DAA)(n=109).The choice of approach was related to the surgeons’practices;the implant types were similar and unrelated to the approach.Dislocation rates and other complications were reviewed after a minimum followup of 6 mo.RESULTS Both treatment groups had similarly aged patients(mean age:82 years),sex ratios,patient body mass indexes,and patient comorbidities.Surgical data(surgery delay time,operative time,and blood loss volume)did not differ significantly between the groups.The 30 d mortality rate was higher in the PL group(9.9%)than in the DAA group(3.7%),but the difference was not statistically significant(P=0.052).Among the one-month survivors,a significantly higher rate of dislocation was observed in the PL group(14/154;9.1%)than in the DAA group(0/105;0%)(P=0.002).Of the 14 patients with dislocation,8 underwent revision surgery for recurrent instability(posterior group),and one of them had 2 additional procedures due to a deep infection.The rate of other complications(e.g.,perioperative and early postoperative periprosthetic fractures and infection-related complications)did not differ significantly between the groups.CONCLUSION These findings suggest that the DAA to bipolar hemiarthroplasty for patients with femoral neck fractures is associated with a lower dislocation rate(<1%)than the PL.

A coupled thermo-mechanical peridynamic model for fracture behavior of granite subjected to heating and water-cooling processes

Thermal damage and thermal fracture of rocks are two important indicators in geothermal mining projects.This paper investigates the effects of heating and water-cooling on granite specimens at various temperatures.The laboratory uniaxial compression experiments were also conducted.Then,a coupled thermo-mechanical ordinary state-based peridynamic(OSB-PD)model and corresponding numerical scheme were developed to simulate the damage of rocks after the heating and cooling processes,and the change of crack evolution process was predicted.The results demonstrate that elevated heating temperatures exacerbate the thermal damage to the specimens,resulting in a decrease in peak strength and an increase in ductility of granite.The escalating occurrence of thermal-induced cracks significantly affects the crack evolution process during the loading phase.The numerical results accurately reproduce the damage and fracture characteristics of the granite under different final heating temperatures(FHTs),which are consistent with the test results in terms of strength,crack evolution process,and failure mode.

Numerical manifold method for thermo-mechanical coupling simulation of fractured rock mass

As a calculation method based on the Galerkin variation,the numerical manifold method(NMM)adopts a double covering system,which can easily deal with discontinuous deformation problems and has a high calculation accuracy.Aiming at the thermo-mechanical(TM)coupling problem of fractured rock masses,this study uses the NMM to simulate the processes of crack initiation and propagation in a rock mass under the influence of temperature field,deduces related system equations,and proposes a penalty function method to deal with boundary conditions.Numerical examples are employed to confirm the effectiveness and high accuracy of this method.By the thermal stress analysis of a thick-walled cylinder(TWC),the simulation of cracking in the TWC under heating and cooling conditions,and the simulation of thermal cracking of the SwedishÄspöPillar Stability Experiment(APSE)rock column,the thermal stress,and TM coupling are obtained.The numerical simulation results are in good agreement with the test data and other numerical results,thus verifying the effectiveness of the NMM in dealing with thermal stress and crack propagation problems of fractured rock masses.