Original Fracture Research Articles

CHARACTERISTICS OF FOREARM RE-FRACTURE IN YOUTH ATHLETES

Background:The forearm is the most common site of fracture, and perhaps re-fracture, in the pediatric population. Although both bone forearm (BBFA) fractures represent approximately 30% of pediatric upper extremity fractures, little is known about BBFA re-fractures, particularly among youth athletes.Purpose:To evaluate characteristics of BBFA re-fracture and recurrent fractures.Methods:An IRB-approved retrospective chart review based on CPT and ICD-9/10 codes of forearm fractures (ages 10-18 years) treated by a single academic pediatric orthopedic group from June 2009 to May 2020 was conducted. All BBFA, radial, or ulnar fractures with ipsilateral same-site, or non-identical ipsilateral or contralateral forearm fracture were included. Demographics, injury characteristics, length of immobilization, timing of return to activity, and radiographic data (angulation, distance between radius fracture and ulna fracture [in mm], position of fracture within bone, and radiographic healing). An analysis was performed to evaluate associations of ipsilateral same-site re-fracture versus ipsilateral or contra-lateral non-identical site fractures.Results:Twenty-nine of 686 BBFA and distal radius fractures were identified to have recurrent fracture (4.23%), with an average age of 11.5 years and male-to-female ratio of 6.25:1. 67% of ipsilateral same-site re-fractures occurred within one year. The most common mechanisms of primary fracture were contact sports (40%) and tumbling (30%), and re-fracture occurred 182 days after original fracture.52% percent of recurrent fractures were ipsilateral same-site re-fractures, while 48% occurred in a non-identical site, either ipsilaterally or contralaterally. The most common mechanisms of recurrent fracture were contact sports (38%), falls (38%), and tumbling (14%). Ipsilateral same-site re-fractures compared to other recurrent fractures, were significantly associated with a mid-shaft location (p=0.0029), increased radius to ulna fracture distance (21.14 mm versus 11.3 mm, p=0.0277) [Figure 1], and earlier occurrence following index fracture (re-fracture= 397.33 days versus non-identical recurrent fracture= 884.07 days, p=0.0056). Degree of angulation was not significantly associated with re-fracture.Conclusion:Recurrent fracture may occur at different times and locations following primary injury treatment. Ipsilateral same-site re-fractures tend to occur within the first year of treatment following mid-shaft fractures incurred during contact sports and tumbling, with widely spaced radial and ulnar fracture sites. Further research may be warranted to evaluate biologic, bone health, or personality traits that may lead to recurrent and re-fractures in pediatric forearm fractures.Figure 1.Anteroposterior images of a left forearm demonstrating a primary fracture (A) and a same-site ipsilateral re-fracture (B). Distance between fractures on the radius and ulna are noted.

ANTERIOR CRUCIATE LIGAMENT TEAR FOLLOWING SURGICAL TREATMENT OF PEDIATRIC TIBIAL EMINENCE FRACTURE IN A MULTICENTER COHORT

Background:While operative treatment of displaced pediatric tibial eminence fractures has generally been shown to be safe, post-operative complications including arthrofibrosis, infection, fixation failure, and postoperative ipsilateral ACL injuries remain prevalent. The purpose of this study was to describe the prevalence of and risk factors for post-operative ACL tears in a cohort of patients surgically treated for tibial eminence fracture.Methods:We performed a retrospective review of children undergoing treatment of a tibial eminence fracture at 10 tertiary children’s hospitals.. The primary outcome was subsequent ACL rupture. Patients with 2 year follow up data and those that had met the primary outcome within the 2 year period, were analyzed for demographics, risk factors and survival analysesResults:385 pediatric patients were reviewed. Overall, 46 patients had either 2 year follow up data or met the primary outcome measure of an ACL tear prior to the 2 year mark. Mean age was 11.2 years old (SD 2.8), and the median follow time was 36.4 months (SD 17.7 months) There was a 21.7% incidence of subsequent ACL tear in the cohort analyzed. Subsequent ACL tears occurred at a median of 10.2 months (SD 19.5 months) postoperatively. There was a statistically significant association with higher Myers & McKeever grade tibial spine fractures (Type III and IV) and subsequent ACL rupture (p=0.006). Subsequent ACL tears occurred in patients who were older when they had their original tibial eminence fracture, 13.4 years old versus 11.3 years old (p=0.035). There was no statistically significant relationship between ipsilateral ACL tear and body mass index, operative time, fixation method used, postoperative weight bearing status, type of postoperative immobilization, contact versus non-contact injury mechanism, type of post-operative physical therapy protocol based on chi-squared or t-test (p>0.05).Conclusion:Subsequent ipsilateral ACL tears following operatively treated pediatric tibial eminence fractures in a large multicenter cohort occurred at a rate of 21.7%. They were associated with completely displaced (Type III or IV) tibial eminence fractures, and older patients. Clinicians should therefore continue to follow patients for at least 2 years after treatment of pediatric tibial eminence fractures in order to track this potential complication.

Retaining primary wall roughness for flow in rock fractures and implications on heat transfer and solute transport

Wall roughness is often found to have evident influences on flow-related processes in rock fractures. In this work, we first define the primary wall roughness to have dominating effects on the overall flow, whereas the secondary roughness only generates additional flow resistance and have insignificant impacts on the bulk flow. Accordingly, an effective procedure is presented to quantitatively identify primary and secondary roughness, and the validity of the procedure is tested with flow simulations in a two-dimensional rough fracture. The results show that the reconstructed fracture with only primary roughness can still well resemble the general flow behavior in the original fracture with a steady transmissivity increment of 5% for the Reynolds number from 0.01 to 100. We further examine the effects of both primary and secondary roughness on processes associated with heat transfer and solute transport in fracture flow. It is found that the heat transfer and solute transport behaviors are closely related to the flow behavior under the effect of wall roughness. As the flow velocity increases to cause strong flow inertia, larger eddies can occur to affect the heat transfer and solute transport processes. Although the presence of secondary roughness shows limited effects on the overall transport behaviors, secondary roughness is found to give rise to more irregularly-shaped eddies, which result in different local behaviors. The findings in this study can provide new insights into the roughness effect on fracture flow and associated processes. In addition, the roughness quantification presents a straight-forward evaluation of potential deviations when neglecting small-scale secondary roughness, as is often needed when analyzing larger-scale problems.

Investigation of the stress evolution under the effect of hydraulic fracturing in the application of coalbed methane recovery

The study of stress transfer can delimitate the hydraulic fracturing (HF) range to evaluate the extraction efficiency of coalbed methane (CBM). However, less research has been done to explore the stress change of underground coal seam due to the field test limitations. In this paper, a total of 9 stress monitoring boreholes (SMBs) are designed to investigate the stress evolution of coal seam during HF through field experiments. Although the middle-low pressure fracturing may cause some stress concentrations, the stress could completely release in the period of subsequent mining, which will not cause potential safety hazards. The stress increase direction is more likely to extend to the original fracture area, especially the direction of loose ring in front of coal seam. The range of stress increase is inversely proportional to the distance to the hydraulic fracturing borehole (HFB) in the same direction, except for the geological structure development areas. The plastic ring will expand with an increasing radius R1 along with the stress increase of coal seam until the radial stress increment Δσrp of outer wall of plastic ring decreases to zero. The effective stress affecting range is about 140 m according to the analysis of stress transfer at different time during HF. The stress no longer increases and gradually decreases to stability after fracturing. The stress transfer method is one of ways to represent the effective region of field HF and enrich the evaluation system for HF affecting range.

Formation damage mitigation mechanism for coalbed methane wells via refracturing with fuzzy-ball fluid as temporary blocking agents

During drainage and production from coalbed methane (CBM) wells, the reservoir is prone to formation damage in the form of blockage of the seepage channels by coal fines or invasion of external water, which inevitably causes a significant decline in the productivity of the wells. To restore their productivity, temporary blocking materials (TBMs) are typically used to seal the original fractures for refracturing treatments. In this study, a special fuzzy-ball temporary blocking fluid (FTBF) was designed to effectively mitigate the formation damage through the refracturing operation. The performance of the FTBF was analysed via experiments, application to two case studies, and its formation damage mitigation mechanisms. The following results were obtained: (1) From the experimental analysis, it was observed that the FTBF increased the water resistance in the fracture and it was less than the gas resistance. (2) In Case one, there was no gas production before the refracturing; however after the refracturing, the daily gas production rose to 494 m3. In Case two, the daily gas production of the well before the refracturing was intermittent and less than 80 m3; however, after the refracturing, the gas production remained stable at 220 m3. (3) The analysis of damage mitigation mechanisms revealed that firstly, sodium dodecyl sulfate improved the viscoelasticity of FTBF and its chemical affinity to water, which enhanced the mitigation of the formation damage by water invasion; secondly, the viscoelastic characteristics of the vesicles enabled it to modify the mechanical properties of the rock and consequently improving the refracturing process; thirdly, sodium dodecyl benzene sulfonate provided excellent dispersion stability by adsorption of coal fines in the proppant pack to enhance the fracture conductivity. This study provided a reliable basis for understanding the mechanisms and application of FTBFs in mitigating the formation damage through refracturing CBM wells.

Torsion control of the electronic and optical properties of monolayer WS2: A first-principles study

The paper systematically investigates the effects of torsional deformation for monolayer graphene-like transition metal disulfide-WS 2 using first-principles calculations. It demonstrates that the geometrical, electronic, and optical properties are influenced distinctively by torsion. The electronic structure analysis reveals that torsion can regularly manipulate the energy level. Torsion improves the intrinsic absorption long-wave cutoff wavelength from 0.639 μm to 0.850 μm. In addition to studying the effect of torsion on the optical properties of monolayer WS 2 , dielectric function, absorption coefficient, reflectivity, and loss function are analyzed. The absorption edge threshold, maximum absorption coefficient, and reflectivity all decrease with the torsion angle increase. When the torsion angle reaches 20°, the electronic structure and optical properties change significantly due to the original bond fracture. This paper provides new possibilities for designing materials on demand.

Anatomical Location of Initial and Repeat Mandible Fractures: A 5-Year, Multi-Institution Retrospective Study

The purpose of the present study was to investigate new fracture patterns resulting from low velocity mechanisms in subjects who had previously fractured their mandible and had been treated with open reduction and internal fixation (ORIF) or closed reduction. A multi-institutional retrospective cohort study was designed to analyze subjects presenting at 2 tertiary care centers with mandibular fractures with specific interest in subjects who had repeat mandible fractures. Variables recorded included demographic (age, sex, etc) data, fracture location of all fractures treated, and the location of previous fracture. Descriptive and bivariate analyses were completed of the data. The sample included a total of 492 subjects and 875 total fractures from both institutions. Four hundred fourty-four (91.1%) were male. The average age of all subjects was 36.4 ± 14.9 years. Twenty-six (5.28%) subjects were previously treated for a mandible fracture. All subjects' subsequent fractures occurred outside of previous ORIF except for 1 subject. Original fracture location (P = .596) and previous ORIF type (P = .689) did not influence if the subsequent fracture was within a site of previous ORIF. The present study demonstrates that repeat mandible fractures are relatively rare, likely to occur only 5% of the time at large tertiary care centers. The repeat fracture is not likely to occur in a site of previous ORIF, regardless of the ORIF modality. Furthermore, the fracture is likely to occur on the contralateral side. This is 1 of the largest data sets on repeat mandible fractures, which, given their rarity, are difficult to study.

Anterior Cruciate Ligament Tear Following Operative Treatment of Pediatric Tibial Eminence Fractures in a Multicenter Cohort

Postoperative ipsilateral anterior cruciate ligament (ACL) tears after tibial eminence fracture fixation has been previously noted in the literature. This study aims to describe the prevalence of and risk factors for postoperative ACL tears in a cohort of patients operatively treated for tibial eminence fracture. A retrospective review of children undergoing treatment of a tibial eminence fracture at 10 tertiary care children's hospitals was performed. The primary outcome of interest was subsequent ACL rupture. Incidence of ACL tear was recorded for the entire cohort. Patients who sustained a postoperative ACL tear were compared with those without ACL tear and analyzed for demographics and risk factors. A subgroup analysis was performed on patients with a minimum of 2-year follow-up data or those who had met the primary outcome (ACL tear) before 2 years. A total of 385 pediatric patients were reviewed. 2.6% of the cohort experienced a subsequent ACL tear. The median follow-up time was 6.5 months (SD=6.4 mo). Subsequent ACL tears occurred at a median of 10.2 months (SD=19.5 mo) postoperatively. There was a statistically significant association with higher grade tibial spine fractures (Myers and McKeever type III and IV) and subsequent ACL tear (P=0.01). Patients with a subsequent ACL tear were older on average (13.5 vs. 12.2 y old), however, this difference was not statistically significant (P=0.08). Subgroup analysis of 46 patients who had a 2-year follow-up or sustained an ACL tear before 2 years showed a 21.7% incidence of a subsequent ACL tear. There was a statistically significant association with higher grade tibial spine fractures (Myers and McKeever type III and IV) and subsequent ACL rupture (P=0.006) in this subgroup. Postoperative ACL tears occurred in patients who were older at the time that they sustained their original tibial eminence fracture (13.4 vs. 11.3 y old, P=0.035). Ipsilateral ACL tears following operatively treated pediatric tibial eminence fractures in a large multicenter cohort occurred at a rate of 2.6%. However, in those with at least 2 years of follow-up, the incidence was 21.7%. Subsequent ACL tear was more likely in those with completely displaced (type III or IV) tibial eminence fractures and older patients. Level III-retrospective cohort study.

Microstructural evolution and mechanical properties of the friction stir welded Al[sbnd]Cu dissimilar joint enhanced by post-weld heat treatment

Dissimilar butt joint of pure aluminum and commercially pure copper was prepared using friction stir welding (FSW) process and subsequent post-weld heat treatment (PWHT) was also performed to improve the mechanical properties of the joints. The microstructural evolution of the intermetallic compounds (IMCs) was principally characterized by optical microscopy (OM), scanning electron microscopy equipped with energy diffraction spectrometer (SEM-EDS), X-ray diffraction (XRD), electron backscatter diffraction (EBSD) and high-resolution transmission electron microscopy (HRTEM). The results suggested that the IMCs layer played a critical role on the metallurgical bounding. A 1.9 μm thickness of AlCu IMCs layer successfully achieved by the post annealing treatment which was composed of dominated Al2Cu phase with average grain size of 0.72 μm and small proportion of Al4Cu9 phase. This thin IMCs layer with very fine grain structure and further refined Al matrix in stir zone promoted the improvement of total joint strength from 79% towards 95% of Al base material. Moreover, the failure mode of the FS Welds converted into the mixed fracture from original brittle fracture. While the very low strength with high brittleness of the joint was mainly attributed to the thicker thickness of IMCs layer containing coarse Al2Cu grains with average grain size of 2.6 μm, which produced by the solution treatment. It was established that the existence of the IMCs layer was the main contribution to the distinct rise in microhardness. In addition, the high fraction of high angle grain boundaries of Al2Cu phase indicated the occurrence of grain bulging mechanism through grain boundary migration during annealing treatment. The grain growth behavior of IMCs layer revealed that a core-shell structured AlCu-Al4Cu9 particles probably occurred in the Al2Cu matrix.

Comparison of surgical effects between extension and flexion type of distal radius fracture

To compare therapeutic effects of internal fixation with volar locking plate in treating extension and flexion type of distal radius fracture (DRF). From January 2015 to June 2018, 103 patients with DRF were retrospectively analyzed. According to original fracture displacement direction, patients were divided into extension fracture(Colles) group and flexion fracture (Smith) group. In Colles fracture group, there were 24 males and 44 females aged from 20 to 79 years old with an average of (59.0±13.4) years old;according to AO classification, 9 patients of type A2, 13 patients of type A3, 16 patientsof type C1, 17 patients of type C2 and 13 patients of type C3;the time from injury to operation ranged from 2 to 9 days with an average of (3.9±0.8) days. In Smith fracture group, there were 15 males and 20 females, aged from 27 to 87 years old with an average of (60.1±15.3) years old;according to AO classification, 4 patienst of A2, 7 patients of A3, 14 patients of C1, 5 patients of C2 and 5 patients of C3;the time from injury to operation ranged from 2 to 6 days with an average of (4.1±0.9) days. Operation time, fracture healing time and postoperative complications were recorded between two groups. Disabilities of arm, shoulder and hand (DASH) score at 6 and 8 weeks, 6 and 8 months were used to evaluate functional recovery of affected limbs during each follow up. Volar tilt, radial inclination and radius height were measured at 8 months after operation. Mayo score was measured at 8 months after operation to evaluate recovery of limb function. All patients were followed up for 8 to 30 months with an average of (14.8±4.3) months, and no difference in follow up between two groups (P> 0.05). There were no statistical differences in operation time, fracture healing time and postoperative complications between two groups(P>0.05). DASH score at 6 and 12 weeks in Colles fracture group were (37.24±5.08) and (19.68±4.55), while in Smith fracture group were (39.05±4.79) and (23.44±4.21);Colles fracture group was better than that of Smith fracture group (P<0.001);while there were no differences in DASH score at 6 and 8 months between two groups (P>0.05). Volar tilt of Smith fracture group (11.1±3.1)° was better than that of Colles fracture group (8.6±4.1) °, and there were no significant difference in radial inclination and radius height between two groups(P>0.05). Also there was no significant difference in Mayo score between two group(P>0.05). Patients with Colles fracture and Smith fracture could receive good reduction and fixation through volar locking plate. The radiographic parameters of both groups recovered satisfactorily after operation. Recovery of volar tilt of Smith fracture group is better than that of Colles fracture group, and early recovery function of Colles fracture group is better than that of Smith group, but there is no significant difference in long-term wrist joint function and incidence of postoperative complications between two groups.

Fracture surface analysis and quantitative characterization of gallium arsenide III-V semiconductors using fractography

Gallium arsenide (GaAs) is used in the most demanding semiconductor applications, including in the medical, aerospace and communication industries, where significant mechanical stresses are experienced during operation. Mechanical stresses from thermal expansion and mechanical loading can result in the fracture of GaAs crystals, a leading cause of semiconductor device failure. Unfortunately, the underlying fracture mechanisms in GaAs III-V semiconductors are currently not well understood. In this manuscript, we present a quantitative approach to identify the main GaAs fractographic features and correlate these to a crystal’s original mechanical fracture strength. In addition, detailed fractographic analysis was used to estimate the crystal hackle constant (analogous to the mirror constant in isotropic media), AXH110〈221〉= 1.58 MPa√m on the {110} cleavage planes of GaAs. Finally, crystal stereography and analytical geometry was used to confirm that the fractographic features correspond to the intrinsic symmetries of single-crystal GaAs.

Are cranial peri-mortem fractures identifiable in cremated remains? A study on 38 known cases.

Accurate identification and analysis of signs of trauma on human bone is one of the mainstays of forensic pathology. However, when a forensic pathologist has to deal with charred remains, the task become extremely difficult, because tissues are subjected to severe morphological alterations and their assessment can be critically distorted. We analyzed 38 individuals with peri-mortem skull fractures due to falls from height (17 cases), traffic accidents (16 cases), gunshots wounds (5 cases), of which we had the demographic and clinical data and the autopsy report with the description and photographic records of the fracture lines. After autopsy, the bodies were cremated in gas furnaces and the analysis of cremated cranial remains was conducted in order to verify if it was possible to reconstruct the original peri-mortem fractures and verify differences between known peri-mortem and post-mortem fractures. After 90min and exposure to temperatures up to 1280°C, in less than a third of cases (11-29%) the original peri-mortem fracture pattern could be found and reconstructed. The edges and the surface of the fractures can preserve their proper morphology, or they can be affected by post-mortem heat-induced fractures and deformations. Interestingly whenever peri-mortem fracture margins showed the evidence of yellow/brownish colouration, a matte appearance was observed, much different from post-mortem fractures, which may provide further food for thought for the identification of peri-mortem fractures after the cremation process.

Repair of proximal humerus fracture nonunions using a standardized treatment algorithm: a case series.

Nonunion of fractures about the proximal humerus represents a rare and complex problem. The purpose of this study was to evaluate the clinical and functional outcomes following proximal humerus fracture (PHF) nonunion repair using a plate and screw construct with a direct comparison to those experienced following operative fixation of acute PHF using a plate and screw construct. Two separate patient cohorts were included in this study. The first consisted of 16 patients diagnosed with a non-united PHF who underwent operative nonunion repair treated with a standard algorithmic approach. The comparison group consisted of 173 patients who achieved union following initial open reduction and internal fixation of an acute PHF treated with a proximal humerus locking plate construct. All patients had at least 12months of postoperative follow-up. Outcomes were assessed for both groups using American Shoulder and Elbow Surgeons (ASES) scores, visual analog scale (VAS) pain scores, and postoperative shoulder range of motion (ROM). Statistical analyses were used to compare these outcome measures between the two cohorts. The nonunion repair cohort consisted of eleven surgical neck nonunions and five nonunions of both the surgical neck and greater tuberosity. Ten patients had undergone surgical treatment for their original fracture, while six were initially treated non-operatively. All patients had Boileau type 3 sequelae of their proximal humerus fracture. Union was achieved in all patients at a mean of 5.4months following nonunion repair. Complications included hardware failure requiring revision in two patients (12.5%) and avascular necrosis requiring conversion to anatomic total shoulder arthroplasty following union in one patient (6.3%). The nonunion repair and acute fracture cohorts did not differ with respect to mean ASES scores, VAS pain scores, or active shoulder ROM at any postoperative time point. Surgical repair of PHF nonunion is a viable treatment strategy that can lead to consistent bony healing with outcomes comparable to those of patients who achieve fracture union following initial surgical repair of an acute proximal humerus fracture. Surgeons should be cognizant of mechanical considerations that may lead to early failure.

On the cleavage hoop stress responsible for crack path deflection and notch-induced anisotropic fracture in cold drawn pearlitic steel: Revisiting John Ford’s Monument Valley

In this paper a study is presented of the fracture behaviour in the presence of notches of high-strength pearlitic steel with different cold drawing degree. To this end, axisymmetric notched samples with a circumferentially-shaped notch of very distinct geometries (sharp and blunt, deep and shallow) were taken from wires with different levels of drawing from the initial hot rolled bar (not cold drawn at all) to the final commercial product (prestressing steel wire: heavily cold drawn). Experimental results show that cold drawn steels exhibit a markedly anisotropic fracture behaviour in the form of fracture path deviation from the original transverse fracture path perpendicular to the wire axis or cold drawing direction. Present paper proposes a key variable governing the notch-induced anisotropic fracture process: the cleavage hoop stress as the relevant factor promoting this sort of fracture path deviation in the most heavily cold drawn pearlitic steel wires

A Simple Physical Therapy Algorithm Is Successful in Decreasing Skilled Nursing Facility Length of Stay and Increasing Cost Savings After Hip Fracture With No Increase in Adverse Events.

Introduction:Shorter length of stays (LOS) at a Skilled Nursing Facility (SNF) after hip fracture surgery would be expected to lead to costs savings for the healthcare system. Evidence also suggests that shorter SNF stays also leads to improved 30-day outcomes, thus compounding this value proposition. Our Integrated Fragility Hip Fracture Program created a simple algorithm at discharge to provide each post-operative hip fracture patient with an expected SNF LOS. We studied whether this intervention produced a shorter SNF LOS and other observable short-term outcomes.Methods:We retrospectively reviewed all original Medicare hip fracture patients treated with operative fixation who were admitted to our hospital in 2015, 2017 and 2018. We selected patients who were discharged to a single SNF following hospitalization, and excluded patients with incomplete records. The algorithm for the expected LOS recommendation was based on the degree of assistance the patient needed for ambulation: 7 days (“0-person assist”), 14 days (“1-person assist”), or 21 days (“2-person assist”). We compare the SNF LOS of our hip fracture patient population between those discharged to a program participant, those SNF that agreed to this algorithm, and those discharged to a non-program participant SNF.Results:We identified 246 patients meeting our selection criteria. 69 were discharged to a program participant SNF. Patients discharged to a participant SNF had similar baseline demographics and ASA distributions to those discharged to a non-participant provider. There was a statistically significant difference in length of stay between the groups, with program participant patients spending an average of 23 days at the SNF while the control group spent an average of 31 days. (p < 0.001). Program participant discharges were also associated with additional cost savings. There was no significant difference in ED visits within 90 days of discharge.Discussion:SNF LOS for geriatric hip fractures can be decreased with implementation of a simple physical therapy driven algorithm based on the patient’s ambulatory independence at hospital discharge. Conclusion: This is a simple, yet completely unique program that seems to have increased the value of healthcare provided.

A fully coupled seepage–heat transfer model including a dynamic heat transfer coefficient in fractured rock sample with a single fissure

Conventional seepage–heat transfer models in simulating the heat transfer between fluid and rock in fractures mainly involve one-way coupling and do not consider the influence of temperature on the seepage. Moreover, it is an enormous challenge to define parameters of the explicit heat transfer between the rock and fluid. In order to resolve these shortcomings, a two-way fully coupled model of the seepage–heat transfer in the fractured rock was established in the present study. Based on the original geometric structure of the experimental device, combined with the actual engineering scale, the local dynamic heat transfer coefficient of the fractured rock was established, which is related to the fracture aperture, flow velocity and thermal parameters. Then, the proposed model was verified through the experiment and excellent agreement was achieved in this regard. It was found that the dynamic heat transfer coefficient changes the temperature distribution of fluid and rock in the original static heat transfer coefficient fracture system. The proposed model simplifies the parameters required for the calculation of the heat transfer coefficient. These parameters are related to characteristic variables, such as velocity and rock temperature, and can be simply obtained from standard laboratory tests.

Reduction of Neglected Displaced Fractures of the Distal Femoral Physis.

We performed open osteoclasis, soft-tissue release, and fracture fragment reduction and fixation to treat 10 cases of neglected physeal fractures of the distal aspect of the femur with severe deformity. To our knowledge, no specific surgical procedure for this problem has been reported in the literature. The procedure is typically performed through an extensile anterolateral approach. With use of an osteotome, the typically abundant fracture callus is disrupted and partially removed to recreate the original fracture line. Through periosteal dissection, an extensive musculoperiosteal detachment and release is achieved to facilitate fracture reduction while protecting the physis from further injury. Knee rehabilitation in closed, nondisplaced or minimally displaced fractures1.Open callus osteoclasis in combination with a Z-shaped quadriceps tenoplasty, reduction, and plaster cast immobilization2.Open subperiosteal osteoclasis, reduction, and tibial traction3.Open callus osteoclasis, reduction, and condylar plating4.Sequestrectomy with preservation of a periosteal sleeve to treat osteomyelitis complicating an open fracture1.Transfemoral amputation to treat gas gangrene or vascular injury following severe open injury1,5-7. This procedure was developed in remote medical facilities where patients are often first seen >21 days after the original injury. By that time, closed reduction or standard open reduction and internal fixation techniques are no longer possible. After 6 months of fracture age, the procedure is inefficient. This procedure allows correction of limb malalignment and shortening while preserving the growth plate1. In some cases, hypertrophic fracture callus might be mistaken for the femoral diaphysis.An extensive musculoperiosteal release will facilitate reduction of the fracture fragments.The adequacy of reduction must be assessed in all 3 planes intraoperatively.The adequacy of reduction must be assessed in all 3 planes intraoperatively.The adequacy of reduction must be assessed in all 3 planes intraoperatively.

Brazilian tensile failure characteristics of marine shale under the hydration effect of different fluids

In this paper, shale gas cores from the Lower Silurian Longmaxi Formation in the Zhaotong National Shale Gas Demonstration Area were selected to study the hydration effect of different fluids on the fracture morphology inside the shale, the rock tensile strength and the Brazilian tensile failure mode. Fresh water and slick water were adopted for hydration pretreatments and the CT technique was used to compare the changes of the fabric in the shale. Then, Brazilian tensile tests were carried out to study the tensile strength and tensile failure modes of the shale specimen after hydration pretreatment. Finally, two horizontal wells in the study area were selected to perform pilot tests of hydration pretreatment in their fracturing operation sites. And the following research results were obtained. First, in the process of spontaneous imbibition, the hydration effect of fresh water is superior to that of slick water in promoting the fracture complexity of marine shale in the same hydration duration. Second, fresh water has greater surface tension and lower viscosity and its hydration effect can not only promote the propagation of original fractures but induce new micro-fractures or branches, while the hydration effect of slick water mainly promotes the propagation of original fractures. Third, due to hydration effect, marine shale is damaged and its tensile strength is reduced. After the hydration pretreatment by fresh water and slick water, the tensile strength of the shale specimens are reduced by 35.6% and 18.1%, respectively. Fourth, according to the propagation paths of main fractures, the Brazilian tensile failure modes of hydrated shale can be divided into four types (i.e., step shaped, dog-leg shaped, branching shaped and arc shaped) or their combinations, while the tensile failure mode of unhydrated shale is only a straight line. Fifth, hydration effect can effectively increase the complexity of the hydraulic fractures in marine shale, so if the conditions permit, it is recommended to inject a certain amount of fresh water at a high pumping rate within the limited pressure after perforation and to shut in the well until the hydraulic fracturing operation. And in order to reduce the difficulties of pumping the proppant during the hydraulic fracturing operation, a pumping strategy of “low proppant concentration, large volume of slurries” can be adopted to reach the expected proppant volume.

Natural mineralized fractures from the Montney-Doig unconventional reservoirs (Western Canada Sedimentary Basin): Timing and controlling factors

Characterizing the origin of natural fractures in organic-rich fine-grained deposits is key to constraining permeability evolution in these potential source rocks and tight reservoirs, as well as to assess the hydraulic connectivity of the fluid systems in which they develop.Differently oriented calcite-filled fractures (i.e. veins), hosted by organic-rich mudrocks of the Lower-Middle Triassic Montney-Doig unconventional resource play (Western Canada Sedimentary Basin), were sampled in sub-surface well cores from British Columbia. A multidisciplinary approach (including sedimentology, Rock-Eval pyrolysis, petrography, O–C–Sr isotope geochemistry and fluid inclusion microthermometry) was applied to host-rocks and fracture filling calcites.The results demonstrate the relevance and usefulness of such multidisciplinary studies to gather insights on: 1) the lithology-related factors controlling fracture occurrence; 2) the timing of fracture opening and the origin of the circulating paleo-fluids; 3) the openness of the fluid system through time.More specifically, host-rock facies (particularly grain size) and vertical facies changes appear to be the leading factors controlling fracture occurrence. A less relevant role was played by the occurrence of diagenetic carbonates, while TOC possibly did not control fracture occurrence.Three generations of calcite cemented fractures were identified. Vertical fractures (first generation) post-dated the onset of oil generation (Late Cretaceous). Horizontal, bedding-parallel fractures (second generation) post-dated the onset of gas generation and possibly opened close to maximum burial, corresponding to peak hydrocarbon (CH4) generation (Late Cretaceous - Early Paleogene). Vertical fractures (third generation) post-dated the horizontal ones and opened during basin uplift (Middle to Late Paleogene).The consistent petrographic and geochemical features of all the calcite cements point to parent fluids in equilibrium with the host-rock lithologies, that possibly behaved as a closed hydraulic system during Late Cretaceous to Paleogene time; this would support the hypothesis that, at least in the portion of the basin investigated, the Montney Fm also acted as source rock of the unconventional system.

Morbidity and mortality of surgically treated pathologic humerus fractures compared to native humerus fractures.

Despite an increasing prevalence of patients sustaining pathologic fractures of neoplastic origin, few studies have investigated 30-day postoperative complication profiles after surgical treatment of pathologic humerus fractures. The purposes of this study were to use a large nationally representative database to determine short-term complication profiles after surgical treatment of pathologic humerus fractures and assess how these complications compared with more commonly studied native humerus fractures. Using the National Surgical Quality Improvement Program database, we identified 30,866 patients who underwent surgical treatment for either pathologic (n = 449) or native humerus fractures (n = 30,417) from 2007 to 2017. Thirty-day postoperative complication profiles were ascertained and compared between the 2 groups using χ2 analyses. Three logistic regression models were then performed to determine which complications were primarily attributable to the pathologic fracture itself vs. the increased comorbidity burden faced by these patients. Patients with pathologic humerus fractures experienced significantly higher rates of death (6.0% vs. 0.3%, P < .001), serious adverse events (12.2% vs. 3.7%, P < .001), minor complications (15.8% vs. 4.8%, P < .001), extended postoperative lengths of stay (42.3% vs. 21.3%, P < .001), discharge to facilities (22.3% vs. 13.5%, P < .001), and readmissions (14.8% vs. 3.4%, P < .001) compared with patients with native humerus fractures. With respect to specific complications, patients with pathologic fractures were at significantly higher risk of pulmonary complications (1.3% vs. 0.3%, P < .001), renal complications (0.7% vs. 0.2%, P = .007), thromboembolic complications (1.6% vs. 0.6%, P = .01), and transfusions (15.1% vs. 4.1%, P < .001). After surgical treatment, patients with pathologic humerus fractures had significantly higher complication rates compared with native humerus fractures, suggesting that guidelines and treatment algorithms for native humerus fractures may not be generalizable for those of pathologic origin. These findings have significant implications for preoperative patient counseling and may be used to negotiate higher reimbursement rates for these patients given a significantly higher morbidity and mortality than was previously described in literature. Postoperatively, orthopedic surgeons should closely monitor patients with pathologic humerus fractures for deep vein thrombosis, renal complications, and pulmonary complications, use blood-sparing techniques, and employ a multidisciplinary approach to help manage and prevent a more heterogeneous profile of postsurgical complications.