Characteristics of Acoustic Emission Waveforms Induced by Hydraulic Fracturing of Coal under True Triaxial Stress in a Laboratory-Scale Experiment

Hydraulic fracturing (HF) is an effective technology to prevent and control coal dynamic disaster. The process of coal hydraulic fracturing (HF) induces a large number of microseismic/acoustic emission (MS/AE) waveforms. Understanding the characteristic of AE waveforms’ parameters is essential for evaluating the fracturing effect and optimizing the HF strategy in coal formation. In this study, laboratory hydraulic fracturing under true triaxial stress was performed on a cubic coal sample combined with AE monitoring. The injection pressure curve and temporal variation of AE waveforms’ parameters in different stages were analyzed in detail. The experimental results show that the characteristics of the AE waveforms’ parameters well reflect the HF growth behavior in coal. The majority of AE waveforms’ dominant frequency is distributed between 145 and 160 kHz during HF. The sharp decrease of the injection pressure curve and the sharp increase of the AE waveforms’ amplitude show that the fracture already runs through the coal sample during the initial fracture stage. The “trapezoidal” rise pattern of cumulative energy and most AE waveforms with low amplitude may indicate the stage of liquid storage space expansion. The largest proportion of AE waveforms’ energy and higher overall level of AE waveforms’ amplitude occur during the secondary fracture stage, which indicates the most severe degree of coal fracture and complex activity of internal fracture. The phenomenon shows the difference in fracture mechanism between the initial and secondary fracture stage. We propose a window-number index of AE waveforms for better response to hydraulic fracture, which can improve the accuracy of the HF process division.

The Establishment of Ore-Controlling Fracture System of Baoginshan Gold Mine Based on Fracture-Tectonic Analysis

The Baoginshan quartz vein type gold mine in the Baimashan-Longshan-Ziyunshan gold belt is the object of study, and the nature of the fracture structure and its ore-controlling effect are studied through surface and pit investigation, and the nature of the ore-controlling structure system and combination pattern of the Baoginshan gold mine is established. The F7 and F9 fractures in the near-east-west (EW) direction are the main fractures, which tend to the north and control the spreading of the ore zone; the northwest (NW) direction secondary tension fracture, with a dominant yield of 221°∠63°, is a T-type fracture in the Riedel shear mode and is the ore-holding structure of the vein-like ore body; the northeast-east (NEE) direction secondary shear fracture, with a dominant yield of 343°∠53°, is a P-type fracture and the combination of the two controls the specific positioning of the ore body. The characteristics and nature of the fracture structures in the whole ore zone, as well as their combination patterns, indicate that the overall ore-controlling fracture system of Baoginshan is a right-going tensional shear fracture zone composed of NW-oriented (T-type) and NEE-oriented (P-type) secondary fractures with F7 and F9 fractures as boundary fractures. The directions of the principal stresses are σ1≈158°∠40°, σ2≈288°∠38°, and σ3≈42°∠28°, respectively. In the next step of the prospecting process, based on increasing the spacing of prospecting pits (to 40m), in-pit drilling is deployed in the upper and lower discs of the NEE secondary fracture along with the tendency and strike for literacy, which can significantly improve the efficiency and effectiveness of prospecting and greatly reduce the cost of prospecting.

Increased Geriatric Treatment Frequency Improves Mobility and Secondary Fracture Prevention in Older Adult Hip Fracture Patients—An Observational Cohort Study of 23,828 Patients from the Registry for Geriatric Trauma (ATR-DGU)

Interdisciplinary orthogeriatric care of older adult hip fracture patients is of growing importance due to an ageing population, yet there is ongoing disagreement about the most effective model of care. This study aimed to compare different forms of orthogeriatric treatment, with focus on their impact on postoperative mobilization, mobility and secondary fracture prevention. In this observational cohort study, patients aged 70 years and older with a proximal femur fracture requiring surgery, were included from 1 January 2016 to 31 December 2019. Data were recorded from hospital stay to 120-day follow-up in the Registry for Geriatric Trauma (ATR-DGU), a specific designed registry for older adult hip fracture patients. Of 23,828 included patients from 95 different hospitals, 72% were female, median age was 85 (IQR 80–89) years. Increased involvement of geriatricians had a significant impact on mobilization on the first day (OR 1.1, CI 1.1–1.2) and mobility seven days after surgery (OR 1.1, CI 1.1–1.2), initiation of an osteoporosis treatment during in-hospital stay (OR 2.5, CI 2.4–2.7) and of an early complex geriatric rehabilitation treatment (OR 1.3, CI 1.2–1.4). These findings were persistent after 120 days of follow-up. Interdisciplinary treatment of orthogeriatric patients is beneficial and especially during in-patient stay increased involvement of geriatricians is decisive for early mobilization, mobility and initiation of osteoporosis treatment. Standardized treatment pathways in certified geriatric trauma departments with structured data collection in specific registries improve outcome monitoring and interpretation.

The Evolution of Olecranon Fractures and Its Fixation Strategies

Introduction. Olecranon fractures are a common fracture of the upper extremity. The primary aim was to investigate the evolution of olecranon fractures and fixation method over a period of 12 years. The secondary aim was to compare complication rates of Tension Band Wiring (TBW) and Plate Fixation (PF). Materials and Methods Retrospective Study for all patients with surgically treated olecranon fractures from 1 January 2005 to 31 December 2016 from a tertiary trauma center. Records review for demographic, injury characteristics, radiographic classification and configuration, implant choices and complications. Results grouped into three 4-year intervals, analyzed comparatively to establish significant trends over 12 years. Results 262 patients were identified. Demographically, increasing mean age (48.7 to 58.9 years old, p-value 0.004) and higher ASA scores (7.1% ASA 3 to 21.0% ASA 3 p-value 0.001). Later fractures were more oblique (fracture angle 86.1 to 100.0 degrees, p-value 0.001) and comminuted (Schatzker D type 10.4–30.0%, p-value 0.025, single fracture line 94.0–66.0%, p-value 0.001). Implant choice, sharp increase in PF compared to TBW (PF 16.0% to PF 80.2%, p-value 0.001). Complication-wise, TBW had higher rates of symptomatic implant, implant and bony failures and implant removal. Conclusion Demographic and fracture characteristic trends suggest that olecranon fractures are exhibiting fragility fracture characteristics (older age, higher ASA scores, more unstable, oblique and comminuted olecranon fractures). Having a high index of suspicion would alert surgeons to consider use of advanced imaging, utilize appropriate fixation techniques and manage the underlying osteoporosis for secondary fracture prevention. Despite this, trends suggest a potential overutilization of PF particularly for stable fracture patterns and the necessary precaution should be exercised.

Risk factors for secondary fractures to percutaneous vertebroplasty for osteoporotic vertebral compression fractures: a systematic review

Background Osteoporotic vertebral compression fracture (OVCF) is one of the most common fragile fractures, and percutaneous vertebroplasty provides considerable long-term benefits. At the same time, there are many reports of postoperative complications, among which fracture after percutaneous vertebroplasty is one of the complications after vertebroplasty (PVP). Although there are many reports on the risk factors of secondary fracture after PVP at home and abroad, there is no systematic analysis on the related factors of secondary fracture after PVP. Methods The databases, such as CNKI, Wan Fang Database and PubMed, were searched for documents on secondary fractures after percutaneous vertebroplasty published at home and abroad from January 2011 to March 2021. After strictly evaluating the quality of the included studies and extracting data, a meta-analysis was conducted by using Revman 5.3 software. Results A total of 9 articles were included, involving a total of 1882 patients, 340 of them diagnosed as secondary fractures after percutaneous vertebroplasty. Conclusion The additional history of fracture, age, bone mineral density (BMD), bone cement leakage, intravertebral fracture clefts and Cobb Angle might be risk factors related to secondary fractures after percutaneous vertebroplasty for osteoporotic vertebral compression fractures. The height of vertebral anterior and body mass index (BMI) were not correlated.

Functional and clinical outcome of MIPPO anterolateral plating for proximal tibia fracture both proximal one third and coronal intrarticular fracture

<p class="abstract"><strong>Background: </strong>The proximal tibial fractures are one of the commonest intraarticular fractures. Generally these injuries fall into two broad categories, high energy fractures and low energy fractures. The tibial plateau fractures are mostly due to high velocity road traffic accidents and fall from height, where fractures result from direct axial compression, usually with a valgus (more common) or varus moment and indirect shear forces.</p><p class="abstract"><strong>Methods: </strong>This is a prospective study and includes operations by MIPPO technique that were undertaken between January 2020 till June 2021 in RNT government hospital; Udaipur. The total number of cases studied were 25 with the youngest being 25 years old and oldest 70 years old. Intraoperative complications were noted. Functional outcome was assessed using Modified Rasmussen’s Criteria.</p><p class="abstract"><strong>Results: </strong>Patients with fracture in our study occurred between the age of 25 to 70 years with maximum incidence involving the productive age group of 21-30 years (90%). Majority of the patients was males- 90%.</p><p class="abstract"><strong>Conclusions: </strong>From the minimally invasive percutaneous plate osteosynthesis of proximal tibial fracture there is an increase in the complexity of proximal tibial fractures with increasing road traffic accident. As most of the patients sustained these fractures belong to physically highly active and productive age group, they need optimal treatment to get back to their previous work capacity and avoid long term complications like osteoarthritis. We treated all fractures in our study with MIPPO technique and found rapid healing by secondary fracture union and hence achieving strong bone union across the fracture site due to inherent benefits of less tissue damage and minimal disturbance of fracture site biology. We operated 20 proximal tibial fractures with MIPPO technique and observed rapid healing and good functional recovery.</p>

Clinical value of MRI in evaluating and diagnosing of humeral lateral condyle fracture in children

Background Humeral lateral condyle fractures (HLCFs) are common paediatric fractures. Radiographs are hard to accurately evaluate and diagnose the damage of articular epiphyseal cartilage in HLCFs. Methods 60 children who should be suspected to be HLCFs in clinical practice from Dec 2015 to Nov 2017 were continuously included as the first part patients. Subsequently, 35 HLCFs patients with complete follow-up information who had no obvious displacement on radiograph were the second part patients. The sensitivity and specificity of radiograph and MRI in diagnosing of HLCFs and their stability were calculated respectively. Calculated the sensitivity and specificity of each scan sequence of MRI in diagnosing of HLCFs osteochondral fractures. The degree of fracture displacement was measured respectively. Compared the ratio of surgical treatment, secondary fracture displacement and complications between the stable fracture group and the unstable fracture group on MRI in part 2 patients. Results Sensitivity of diagnosing HLCFs by MRI was significantly higher than radiograph (100.00% vs. 89.09%, P = 0.03). Sensitivity of diagnosing integrity of trochlear cartilage chain by MRI was 96.30%, which was significantly higher than that by radiograph (62.96%, P < 0.01). The sensitivity of cartilage sensitive sequence (3D-FS-FSPGR/3D-FSPGR) was different with FS-PDWI and FS-T2WI (P = 0.01 and P = 0.02, respectively). The degree of HLCFs displacement by MRI was higher than radiograph (P < 0.05). In the unstable fracture group, 5 cases (45.45%) had a fracture displacement of more than 2 mm on MRI, which was significantly higher than that in stable fracture group (0.00%, P < 0.01). Conclusions MRI is superior to the radiograph of elbow joint in evaluating and diagnosing children HLCFs and their stability. The coronal 3D-FS-FSPGR/3D-FSPGR sequence is a significant sequence for diagnosing osteochondral fractures in HLCFs. MRI can provide important clinical value for treatment decisions of HLCFs without significant displacement.

Unconventional Well Test Analysis for Assessing Individual Fracture Stages through Post-Treatment Pressure Falloffs: Case Study

Researchers and operators have recently become interested in the individual stage optimization of unconventional reservoir hydraulic fracture. These professionals aim to maximize well performance during an unconventional well’s early-stage and potential Enhanced Oil Recovery (EOR) lifespan. Although there have been advances in hydraulic fracturing technology that allow for the creation of large stimulated reservoir volumes (SRVs), it may not be optimal to use the same treatment design for all stages of a well or many wells in an area. We present a comprehensive review of the main approaches used to discuss applicability, pros and cons, and a detailed comparison between different methodologies. Our research outlines a combination of the Diagnostic Fracture Injection Test (DFIT) and falloff pressure analysis, which can help to design intelligent production and improve well performance. Our field study presents an unconventional well to explain the objective optimization workflow. The analysis indicates that most of the fracturing fluid was leaked off through natural fracture surface area and resulted in the estimation of larger values compared to the hydraulic fracture calculated area. These phenomena might represent a secondary fracture set with a high fracture closure stress activated in neighbor stages that was not well-developed in other sections. The falloff pressure analysis provides significant and vital information, assisting operators in fully understanding models for fracture network characterization.