Fatigue Fracture Research Articles

Effects of functional treatment of V metatarsal bone fracture in athletes – an evaluation of cases

This study presents the rehabilitation process for the management of six cases of fractures of the fifth metatarsal bone in players of various sports playing at high levels of competition in Poland. The course of treatment was based on an intensive rehabilitation protocol with the need for orthopaedic shoe inserts, with full weight bearing on the limb and under close supervision of a physiotherapist. The effectiveness of rehabilitation was assessed by physical examination, X-ray examination and the numerical pain rating scale - NRS. This study focuses on the rehabilitation process for managing fractures of the fifth metatarsal bone in high-level athletes in Poland. The treatment involved an intensive rehabilitation protocol with orthopaedic shoe inserts, full weight bearing, and physiotherapist supervision. The effectiveness of rehabilitation was evaluated through physical exams, X-rays, and the numerical pain rating scale. Introduction Fractures of the fifth metatarsal bone are common in athletes aged 10-29, especially in football, basketball, and dance. Complications include delayed bone fusion and repeat fractures, emphasizing the importance of quick return to fitness. The involvement of physiotherapists and patient positivity is crucial. The debate among clinicians stems from classification variations and interpretations of 'Jones fractures'. Diagnostic and Classification Methods The Lawrence and Bottle classification distinguishes three types of metatarsal fractures: avulsion, Jones, and fatigue fractures. The study presents six cases of conservative treatment for these fractures, showing positive outcomes in returning athletes to competition. Rehabilitation Procedure Patients underwent functional treatment with orthopaedic insoles, immediate weight-bearing, and various therapies like Orthokine®, Exogen, hyperbaric chamber sessions, ESWT, and EPTA. Post-workout treatments included Game Ready®, flossing, manual therapy, dry needling, and lymphatic drainage. Patients also engaged in self-managed rehabilitation exercises. Treatment Results Radiographic examinations showed progressive healing in all cases, with reduced pain and no edema after two weeks. Patients returned to sports within three weeks, with no complaints after 13 months. The study highlights the success of functional treatment in achieving full recovery without complications. Conclusion The study challenges the need for surgical intervention and immobilization in treating fifth metatarsal fractures. Functional treatment led to excellent outcomes and quick return to sports. Literature review supports early mobilization and functional therapy for optimal results. Further research is needed to establish a standard treatment protocol based on evidence-based medicine.

Influence of rolling defects on fatigue crack initiation of leaf spring

ABSTRACT Leaf springs, as vital suspension components in trucks, endure various forces such as torsion, compression, tension and impact, rendering them highly susceptible to fatigue and fracture risks, thereby posing a significant threat to vehicle safety. During the production process of leaf springs, surface decarburisation can easily occur, leading to the formation of numerous surface rolling defects. These defects exert varying influences on the initiation of fatigue crack. This study investigates the influence of various forms of rolling defects caused by decarburisation on fatigue crack initiation in 50CrMnMoNbAT leaf spring through experimental and numerical analysis of fatigue fracture behaviour. The results indicate that fracture locations in the leaf springs are predominantly concentrated approximately 297 mm and 698 mm from the ends. Furthermore, the occurrence of surface decarburisation during the rolling process engenders a significant number of surface rolling defects. Surface defects in leaf springs can be categorised into three forms: Parallel defect, Parcel defect and Occlusal defect. In terms of defect propagation rate, rolling defects on the concave surface are most prone to initiate fatigue cracks, with Occlusal defects exhibiting the highest likelihood of developing internal cracks and the fastest crack propagation rate.

Research on online monitoring method for time-varying tension in transmission lines based on operational modal response

The cumulative overload of conductor tension under severe weather conditions is an important cause of accelerated fatigue fracture of transmission lines. Traditional tension measurement methods require the replacement of ball head hanging rings, which poses safety risks. In this paper, a method for monitoring conductor tension based on acceleration data under operating conditions is proposed. Firstly, a modal order extraction based method for identifying the modal frequencies of conductor operation is proposed, and then the time-varying tension of the conductor is estimated based on the instantaneous modal frequencies. Since this method directly installs sensors on the conductor, there is a certain error in the obtained intrinsic characteristic data of the conductor. Therefore, a modal correction method is used to remove the influence of the sensors. The accuracy of modal identification, modal correction, and tension identification methods is verified through finite element models. Based on the above methods, a monitoring system for conductor tension status is designed, and the feasibility of this system is verified through experiments. Finally, the vibration data obtained from the field engineering pilot test is successfully used for conductor tension analysis. The results show that the proposed method can effectively identify time-varying tension and provide a new approach for monitoring the status of transmission line conductors.

Digital fatigue cracking test and fatigue life assessment of rib-deck joints in orthotropic steel decks

The orthotropic steel decks (OSDs) are vulnerable to fatigue fractures, which will inevitably impair the normal service of the steel bridge panels. To determine the impact of the initial cracks on the fatigue life, this study constructed an evaluation model of the OSD rib-to-deck joints crack based on the fracture mechanics principle. And combined it with the multi-scale finite element analysis model, the digital fatigue test model of the whole bridge was established. Research shows: A typical I-II-III composite crack with the supremacy of type I crack can be seen in the OSD rib-to-deck joints. Fatigue cracks developed at the deck weld toe dominate the fatigue failure mode. Further research revealed that as the depth of cracks increased, the stress on the cross-section was redistributed. The intensity factor then displayed a trend of growing and then gradually flattening or even dropping. Based on the relationship between cracks of different depths and the remaining life of the OSDs, recommendations are given for bridge maintenance. The multi-scale digital fatigue test can provide analysis and simulation methods for the fatigue crack propagation in the steel bridge deck of the bridge in operation.

Investigating the role of geochemistry and geotechnical properties in landslide characterization and triggering mechanisms: A case study from Dir Upper, Khyber Pakhtunkhwa Pakistan

The 83.5 km Chukyatan-Kumrat Upper Dir road plays a crucial role in transportation and tourism in North Pakistan. Despite its significance, the area faces frequent landslides due to hydrometeorological hazards, posing a threat to its stability. This study conducts the first extensive investigation of landslide susceptibility in the region, considering geological features, geotechnical properties, and rock weathering. The road traverses diverse rock formations, including meta-volcanics, andesites, meta-rhyolites, ignimbrites, volcanic ash, granodiorites, and spotted slates, overlain by residual soils. The presence of the Dir fault has led to significant accumulations of loose, weathered rock debris (>100 m deep). Exposed slopes exhibit polygonal stress fractures, joints, and fissures with steep inclinations (>40°), further enhancing instability. Geotechnical analysis reveals a low internal friction angle (28.5°–31.9°) and cohesion (4.1–5.9 kPa) of slope materials, indicating poor shear resistance compared to stable slopes. The unconfined compressive strength of bedrock (10.7–41.5 MPa) ranges from weak to moderate-strong, emphasizing the contribution of weaker rock formations to instability. Acidic soil pH (3.1–4.2) and clay minerals support the prevalence of weathering conditions promoting landslides. Thin section analysis and X-ray diffraction reveal hydrothermal alteration during low-grade metamorphism, leading to the formation of chlorite, smectite, montmorillonite, and zeolites. Additionally, physical weathering has increased quartz content, potentially impacting slope stability. The combined effect of factors such as steep slope geometry, low shear strength with strain-softening properties, rainfall, snowmelt, freeze-thaw activity, slope base cutting for road development, and massive loading from houses contributes to numerous landslides in the region. The study aids effective mitigation and preparedness in the Chukyatan-Kumrat area and offers insights for landslide susceptibility mapping in similar geological settings.

Humeral Component Version Has No Effect on Outcomes Following Reverse Total Shoulder Arthroplasty: A Prospective, Double-Blinded, Randomized Controlled Trial.

Controversy exists regarding the ideal humeral component version to optimize humeral rotation and patient outcomes in reverse total shoulder arthroplasty (rTSA). Patients undergoing primary rTSA for rotator cuff tear arthropathy, a massive rotator cuff tear, or primary osteoarthritis with a rotator cuff tear were randomized to placement of the humeral component in neutral version or 30° of retroversion. Shoulder active range of motion and strength and visual analog scale (VAS) pain, American Shoulder and Elbow Surgeons (ASES), and Patient-Reported Outcomes Measurement Information System Global 10 (PROMIS-10) scores were collected up to 2 years postoperatively. The goal of the study was to determine whether humeral external rotation and internal rotation are affected by humeral component version following rTSA at 2 years postoperatively. Sixty-six patients were included in the analysis. The median follow-up was 26 months for the neutral and 27 months for the 30° retroversion group. No differences between the groups were observed with respect to the primary diagnosis, sex, age, body mass index, or American Society of Anesthesiologists (ASA) class. The 2 groups did not differ significantly in terms of improvement at 2 years in active shoulder abduction (p = 0.969), forward elevation (p = 1.000), internal rotation measured as the highest spinal level reached (p = 1.000), internal rotation with the arm abducted 90° (p = 0.451), external rotation (p = 0.362), or muscle strength in forward elevation (p = 1.000), abduction (p = 1.000), external rotation (p = 0.617), or internal rotation (p = 1.000). The 2 groups did not differ significantly in terms of improvement in postoperative ASES (p = 1.000), PROMIS-10 physical (p = 1.000), or VAS pain scores (p = 0.718) at the time of final follow-up. In the neutral version group, 1 patient underwent revision for instability and 1 for stiffness. One acromial stress fracture occurred in the 30° humeral retroversion group. Scapular notching was observed in 7 (21.2%) of the patients in neutral version group and 5 (15.2%) of the patients in the 30° retroversion group (p = 0.750). Securing the humeral component at neutral version or 30° of retroversion in rTSA resulted in similar active shoulder external rotation, internal rotation, forward elevation, abduction, and strength measurements, complication rates, and VAS pain, PROMIS-10 physical, and ASES scores at 2 years postoperatively. Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Finite Element Analysis of a Rib Cage Model: Influence of Four Variables on Fatigue Life during Simulated Manual CPR.

Cardiopulmonary resuscitation (CPR) is a life-saving technique used in emergencies when the heart stops beating, typically involving chest compressions and ventilation. Current adult CPR guidelines do not differentiate based on age beyond infancy and childhood. This oversight increases the risk of fatigue fractures in the elderly due to decreased bone density and changes in thoracic structure. Therefore, this study aimed to investigate the correlation and impact of factors influencing rib fatigue fractures for safer out-of-hospital manual cardiopulmonary resuscitation (OHMCPR) application. Using the finite element analysis (FEA) method, we performed fatigue analysis on rib cage models incorporating chest compression conditions and age-specific trabecular bone properties. Fatigue life analyses were conducted on three age-specific rib cage models, each differentiated by trabecular bone properties, to determine the influence of four explanatory variables (the properties of the trabecular bone (a surrogate for the age of the subject), the site of application of the compression force on the breastbone, the magnitude of applied compression force, and the rate of application of the compression force) on the fatigue life of the model. Additionally, considering the complex interaction of chest compression conditions during actual CPR, we aimed to predict rib fatigue fractures under conditions simulating real-life scenarios by analyzing the sensitivity and interrelation of chest compression conditions on the model's fatigue life. Time constraints led to the selection of optimal analysis conditions through the use of design of experiments (DOE), specifically orthogonal array testing, followed by the construction of a deep learning-based metamodel. The predicted fatigue life values of the rib cage model, obtained from the metamodel, showed the influence of the four explanatory variables on fatigue life. These results may be used to devise safer CPR guidelines, particularly for the elderly at a high risk of acute cardiac arrest, safeguarding against potential complications like fatigue fractures.

Spatiotemporal Characterization of Microstructure Morphology, Mechanical Properties and Bone Remodeling of Rat Tibia Under Uniaxial Compressive Overload Loading.

Bone tissue is subjected to increased mechanical stress during high-intensity work. Inadequate bone remodeling reparability can result in the continuous accumulation of microdamage, leading to stress fractures. The aim of this work was to investigate the characteristics and repair mechanisms of tibial microdamage under several degrees of overload. Also, we aimed at better understanding the effects of overload on the multi-scale structure and mechanical properties of bone. Sixty 5-month female rats were divided into three groups with different time points. Micro-CT was used to evaluate the three-dimensional microstructure, and three-point bending, quasi-static fracture toughness and creep mechanical test were carried out to evaluate the mechanical properties. SEM was used to observe the morphological characteristics of fracture surfaces. Section staining was used to count the microdamage parameters and numbers of osteoblasts and osteoclasts. The microarchitectures of cancellous and cortical bones in the three overload groups showed different degrees of damage. Overload led to a messy crystal structure of cortical bone, with slender microcracks mixed in, and a large number of broken fibers of cancellous bone. The properties associated with the elastic plasticity, fracture toughness, and viscoelasticity of cortical bone reduced in three groups, with that corresponding to day 30 presenting the highest damage. The accumulation of microdamage mainly occurred in the first 14days, that is, the crack density peaked on day 14. Peak-targeted bone remodeling of cortical and cancellous bones occurred mainly between days 14 and 30. The influence of overload mechanical environment on bone quality at different time points was deeply investigated, which is of great significance for the etiology and treatment of stress fractures.

Fatigue life evaluation of laser welded lap joints of dissimilar aluminum alloys

Abstract Constant amplitude fatigue tests were conducted on 6061/7075 dissimilar aluminum alloy laser welded lap specimens, as well as weld line cross-section hardness measurements. The fatigue test results show that the specimens exhibit multiple fracture modes that exit near the weld seam. The microhardness data on weld line cross-section from 7075 side to 6061 side display a sharp change and the softening phenomenon is serious. The hardness variation in heat affected zone of laser welding is very shallow, and its hardness is close to that of the base material. It was found that there are slag inclusions and pores in the weld seam when observing the fatigue fracture surface using SEM, and a small amount of secondary cracks were generated. However, stress concentration plays a dominant role in causing specimen fracture under fatigue loading, rather than welding defects. Defective specimens are found to have higher fatigue strength. The fatigue life prediction results obtained by the notch stress method and the hot spot stress method are both conservative and fall within two factor lines. The hot spot stress method has relatively higher accuracy for life prediction. The accuracy of both methods in predicting life is influenced by the location of the fracture.

Hydrodissection of the Eighth Cervical Nerve Root for Scapular Girdle Pain Associated With Nonunion of the First Rib Stress Fracture: A Case Report

Hydrodissection of the Eighth Cervical Nerve Root for Scapular Girdle Pain Associated With Nonunion of the First Rib Stress Fracture: A Case Report

Tibial strains are sensitive to speed, but not grade, perturbations during running.

A fatigue-failure process is hypothesized to govern the development of tibial stress fractures, where bone damage is highly dependent on the peak strain magnitude. To date, much of the work examining tibial strains during running has ignored uphill and downhill running despite the prevalence of this terrain. This study examined the sensitivity of tibial strains to changes in running grade and speed using a combined musculoskeletal-finite element modeling routine. Seventeen participants ran on a treadmill at ±10°, ±5°, and 0°; at each grade, participants ran at 3.33 ms-1 and at a grade-adjusted speed -2.50 and 4.17 ms-1 for uphill and downhill grades, respectively. Force and motion data were recorded in each grade and speed combination. Muscle and joint contact forces were estimated using inverse-dynamics-based static optimization. These forces were applied to a participant-adjusted finite element model of the tibia. None of the strain variables (50th and 95th percentile strain and strained volume ≥4000 μɛ) differed as a function of running grade; however, all strain variables were sensitive to running speed (F ≥ 9.59, p ≤ 0.03). In particular, a 1 ms-1 increase in speed resulted in a 9% (≈260 μɛ) and 155% (≈ 600 mm3) increase in peak strain and strained volume, respectively. Overall, these findings suggest that faster running speeds, but not changes in running grade, may be more deleterious to the tibia. • High-magnitude tibial strains that are implicated in stress-fracture development were sensitive to changes in running speed but not grade. • The majority of the variance in measures of tibial strain was accounted for by individual subject variation, reinforcing the importance of inherent musculoskeletal properties in determining the bone strain environment.

Cyclic Fatigue Resistance of Edge File X7 and 2Shape Endodontic Systems: in vitro study.

Objectives: In order to test the resistance of rotary instruments to cyclic fatigue fracture and its importance in root canal preparationthe purpose of this study was to see how different tapers (4% and 6%) affected the cyclic fatigue resistance of the Edge File X7 and 2Shape endodontic systems at 45° and 60°canal curvature.Methods: Eighty NiTi files from two different systems (N= 40 each) were used; Group 1: Edge File X7, Group 2: 2Shape. each group was subdivided into four subgroups (N= 10 for each subgroup). The files were evaluated for cyclic fatigue resistance using a modified custom-made static model with 45°and 60° angles having a radius of 3mm and a diameter of 1.5 mm. Each file was rotated in a continuous rotation motion at 300 rpm with 1.2 N.cm torque for TS1, 300 rpm with 2.5 N.cm torque for TS2, and Edge file X7 was used at 300 rpm and 3 N.cm. Until it fractured. The time it took to separate the files was noted. Each file's number of cycles to failure was computed. A Kolmogorov-Smirnova normality test was done for all groups, and a two-way ANOVA was used to statistically examine the data.Results: The ranking of the groups from the highest to the lowest NCF was as follows: EdgeFile 4% 45 degrees (6594.00), EdgeFile 6% 45 degrees (6317.90), EdgeFile 4% 60 degrees (5682.00), EdgeFile 6% 60 degrees (2142.00), 2Shape 4% 45 degrees (2517.00), 2Shape 4% 60 degrees (535.90), 2Shape 6% 45 degrees (474.50), and 2Shape 6% 60 degrees (213.00). Conclusions: Edge File X7 showed better results than the 2Shape system. EdgeFile X7 4% at 45 degrees showed the highest NCF. The 2Shape system 6% at 60 degree that showed lowest NCF. As the canal curvature increased the NCF decreased. Taper 4% is better than taper 6%.

High fatigue performance and microscopic mechanisms of in-situ TiB2/7050Al composite at different temperatures

In this work, the fatigue properties of in-situ TiB2 particle-reinforced 7050 Al-matrix (TiB2/7050Al) composites at room temperature (RM), 100 ℃ and 150 ℃ were studied, respectively, and the microstructure changes, fatigue fracture characteristics and fracture mechanism were analyzed. The results indicate that when the fatigue temperature increased, the amount of S phase precipitation along grain boundaries increases, forming a banded distribution with TiB2 particles near the grain boundary regions. The RM fatigue limit of the composite is high up to 307.5 MPa. Under the same fatigue strength, TiB2/7050 composites can withstand fatigue cycles far greater than 7050Al alloy. With the increase of temperature, the fatigue performance of the composite gradually decreased, and unlike at RM and 100 ℃, the use of Weibull three-parameter model is necessary to obtain a satisfactory S-N curve at 150 ℃. In some locations of the steady-state crack propagation stage, the direction and spacing of fatigue striations were influenced by grain orientation, grain boundaries and TiB2 particle bands. Therefore, the effects of TiB2 particles, grain boundaries, and precipitations on the fatigue processes were analyzed to reveal the strengthening mechanisms of the composite.

Resonant Fatigue Tests on Polished Drill Pipe Specimens

In this study, the fatigue strength of polished drill pipe specimens was investigated and compared with previous test results of corroded and not-corroded pipes. The resonant fatigue test rig, which was designed and implemented by the University of Pisa, is initially presented by providing a detailed description of the set-up of the machine, the calibration of the strain gauges, the control system, and the correct identification of the vibrational node locations. A polishing rig was also designed and put into operation to remove the corrosion pits from the outer surface of almost the entire length of the drill pipe specimens. After the fatigue tests with the resonant rig, and the observation of the fatigue fracture of the specimens, a few samples were extracted from different zones (corroded and not corroded) of the failed drill pipe specimens. This allowed for investigations to be carried out using a scanning electronic microscope. The obtained results were analyzed using the Murakami model, and a discussion is presented about the effect of the corrosion pits on the fatigue strength.

Abstract GS02-10: Effects of a structured and individualized exercise program on fatigue and health-related quality of life in patients with metastatic breast cancer: the multinational randomized controlled PREFERABLE-EFFECT study

Abstract INTRODUCTION: Patients with metastatic breast cancer (mBC) often experience cancer- and treatment-related side effects that can impair daily life activities and health-related quality of life (HRQoL). Interventions are needed that improve HRQoL by alleviating fatigue and other side effects during palliative BC cancer treatment. Recent evidence-based international guidelines (ASCO, ACSM) recommend exercise for patients with BC during adjuvant treatment for reducing side effects. However, evidence of the effectiveness of exercise in patients with mBC is scarce. The PREFERABLE-EFFECT study (NCT04120298) was designed to assess the effects of a 9-month supervised exercise program in patients with mBC on fatigue, HRQoL, and other cancer- and treatment-related side effects. METHODS: PREFERABLE-EFFECT is a multinational, randomized controlled trial including patients with mBC from five European countries (Germany, Poland, Spain, Sweden, The Netherlands) and Australia. Participants were randomly assigned to usual care or an individualized, structured exercise program consisting of aerobic, resistance, and balance training. The first six months included twice weekly supervised exercise sessions of one hour. In the last three months, one supervised session was replaced by an unsupervised session, supplemented by an exercise App. All participants received general exercise advice (physical activity ≥ 30 min/day) and an activity tracker. Our primary outcomes, physical fatigue (subscale of the EORTC QLQ-FA12) and HRQoL (summary score of the EORTC QLQ-C30), were assessed at baseline, 3, 6, and 9 months. Among other physical fitness outcomes, maximal short exercise capacity was assessed with the Steep Ramp Test. The intervention effects (intention-to-treat) were determined by comparing the change from baseline to 3, 6 (i.e., primary endpoint) and 9 months between groups using separate mixed models for repeated measures, adjusted for baseline values of the outcome variable and stratification factors (mBC line of treatment (1st/2nd vs. 3rd or higher) and study center). A significant improvement of either or both primary outcomes (applying the Bonferroni-Holm method) was considered as successful. RESULTS: Between 2019-2022, we included 357 patients with mBC, with 178 patients randomized to the exercise intervention and 179 to usual care. Patients were, on average, 55.4 years of age (SD=11.1), most patients received 1st or 2nd line of treatment at study enrollment (74.8%) and had bone metastases (73.9%). At 6 months (primary endpoint), participation in the exercise intervention resulted in statistically significant positive effects on both primary outcomes, compared to usual care: physical fatigue was lower (mean difference: -5.3, 95% CI -10.0; -0.6, p=0.027, effect size (ES)=0.22) and HRQoL was better (+4.8, 95% CI 2.2; 7.4, p=0.0003, ES=0.33). Beneficial effects were also found at 3 months (physical fatigue: -3.4, -7.8; 1.0, ES=0.14 and QoL: 3.9, 1.5; 6.3, ES=0.27) and 9 months (physical fatigue: -5.6, -10.9; -0.4, ES=0.24 and QoL: +4.3, 1.4; 7.3, ES=0.31). Further, at the primary endpoint, we found positive exercise effects on physical fitness (+24.3 Watts, 15.5; 33.1, ES=0.42) and numerous QLQ-C30 scales, including social functioning (+5.5, 0.2; 10.8, ES=0.20), pain (-7.1, -12.1; -1.9, ES=0.28) and dyspnea (-7.6, -12.2; -3.0, ES=0.28). Two SAEs occurred (one wrist fracture and one sacral stress fracture), neither related to bone metastases. CONCLUSION: This large multinational study demonstrated significant beneficial effects of a supervised exercise intervention offered during palliative treatment on mBC patients’ fatigue, HRQoL, and other clinically relevant outcomes. Based on these findings, we recommend supervised resistance and aerobic exercise as part of supportive care regimens during palliative treatment of mBC. Citation Format: Anne May, Anouk Hiensch, Johanna Depenbusch, Martina Schmidt, Evelyn Monninkhof, Mireia Pelaez, Dorothea Clauss, Philipp Zimmer, Jon Belloso, Mark Trevaskis, Helene Rundqvist, Joachim Wiskemann, Jana Muller, Carlo Fremd, Renske Altena, Joanna Kufel-Grabowska, Rhode Bijlsma, Lobke van Leeuwen-Snoeks, Daan ten Bokkel-Huinink, Gabe Sonke, Bruce Mann, Prudence Francis, Gary Richardson, Isabel Álvarez, Wolfram Malter, Elsken Van der Wall, Neil Aaronson, Elżbieta Senkus, Ander Urriticoechea, Eva Zopf, Wilhelm Bloch, Martijn Stuiver, Yvonne Wengström, Karen Steindorf. Effects of a structured and individualized exercise program on fatigue and health-related quality of life in patients with metastatic breast cancer: the multinational randomized controlled PREFERABLE-EFFECT study [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr GS02-10.

A Scoping Review of the Epidemiology, Management, and Outcomes of Golf-Related Fractures.

Golf is a popular sport; however, there is a paucity of data in relation to golf-associated fractures, and the rate and timing of returning to golf. The aim of this review is to describe golf-associated fractures, including epidemiology, management, and timing of returning to golf following treatment. A literature search was performed using MEDLINE/PubMed, Embase, and Web of Science. Data were extracted and summarized in a narrative synthesis. A total of 436 articles were identified with an initial search of which 58 met the inclusion criteria. Twelve anatomical sites of golf swing-related fractures were identified, of which 10 sites were specific for stress fractures. The most common sites of golf swing-related stress fractures were the ribs followed by the hook of hamate. There was a common theme of delay to diagnosis, being initially assigned to a soft tissue injury. Most golfers with swing-related stress fractures were able to return to golf with the exception of osteoporotic associated vertebral stress fractures. Timing of returning to golf was between 4 and 12 months for most of the golfers with stress fractures following conservative management. Operative intervention was an option of hook of hamate nonunion, following a stress fracture, and tibial shaft stress fractures. Golf equipment-related fractures were not rare and were associated with major trauma and in some cases associated with significant persistent morbidity. Golf-related stress fractures commonly involve the ribs and hook of hamate; knowledge of this may aid in early diagnosis and appropriate treatment when symptomatic golfers are encountered. Although golf is a noncontact sport, fractures associated with golf equipment can be life changing, and safety training guidelines should be established.

Investigations of fatigue crack growth rate behaviour and life prediction of Si3N4/TiB2 reinforced hybrid metal matrix composites

Many engineering structures and components experience complex fatigue loading throughout their operational lifespan. Economically, it is crucial to forecast the remaining lifespan to prevent catastrophic failure by implementing appropriate inspection schedules. The aim of present work is to investigate the fatigue, and fracture performances of AA7075 alloy-based hybrid MMCs containing Si3N4/TiB2 reinforcement. The composite samples are made by a liquid-state stir-casting process. The study examines the fatigue characteristics of manufactured Hybrid Metal Matrix Composites (HMMCs) by analyzing fatigue crack propagation and fracture toughness under constant amplitude loading with a uniform load ratio of 0.1. The potential influence of reinforcement particles on the fatigue durability of HMMCs was predicted through the application of an 'Exponential Model'. A comparison between the model's performance and experimental findings was carried out. The study suggests that the exponential model accurately predicts fatigue life, showing a maximum percentage deviation of −4.96 %, in close agreement with experimental findings. The fatigue crack growth rate (da/dN) and crack opening displacement (COD) of HMMC indicate that the fatigue life and fracture toughness improve with increase in TiB2 content, up to 6 wt%. The fabricated HMMC with 4wt% Si3N4 and 6 wt% TiB2 particulates demonstrated the highest resistance to fracture and longest fatigue life among others HMMCs and base alloy.

On effect of residual stress on fracture behavior of mandibular reconstruction plates

Titanium reconstruction plates are often used to bridge mandibulectomy defects in load bearing scenarios when bone grafts are not well integrated to the host bone. The residual stress within a standard reconstruction plate is generated when being bent and installed to adapt to a patient-specific anatomical contour and it may have a detrimental effect on the structural stability and reliability of the reconstruction system. This study aimed to evaluate the impact of residual stress on the mechanical strength of the reconstructed mandibular system by utilizing both conventional finite element method (FEM) and eXtended Finite Element Method (XFEM). The mechanical stresses introduced by plate pre-bending and screw tightening were first modeled computationally and the residual stress data induced by the surgical procedure was incorporated to the deformed reconstruction plate for the subsequent biomechanical evaluation. Static and cyclic loading conditions were then imposed on the mandibular plate models to further investigate two common failure types, namely overloading fracture and fatigue fracture. It is revealed that the residual stress could considerably increase the susceptibility of plate fracture. The simulation results demonstrate that the pre-stresses induced by screw tightening are more substantial than that from plate bending during the surgical procedure. The finding is of important clinical implications for surgeons who are commonly involved in selecting and preparing different forms of fixation plates for mandibular reconstruction. This study helps elucidate the key factors contributing on the failure of reconstruction plates and guide the development of more robust and durable mandibular reconstruction systems.

Investigation of ratcheting fatigue behavior and failure mechanism of 1Cr18Ni10Ti pressure pipe under different force amplitudes and internal fluid pressure

This work reports on the development of an improved testing system to examine the effects of force amplitude and internal fluid pressure on ratcheting behavior and failure mechanism of 1Cr18Ni10Ti aero-engine pipe. Experimental results indicate that the ratcheting displacement and its rate during steady stage increase with the increasing force amplitude or internal fluid pressure, exhibiting a reverse tendency to fatigue life. Continuous cyclic softening response until fatigue fracture was observed in all conditions. Furthermore, microstructural evolution was characterized by SEM, EDS, XRD, and EBSD. The critical force amplitude to trigger noticeable dislocation accumulation and transition from austenite to ferrite phase was evaluated to be around 1900 N. The results highlight the decreased high-angle grain boundary (HAGB) and increased dislocation density causing the sample with a higher force amplitude to be more inclined to fracture. The initiation of fatigue crack was accelerated by the accumulation of dislocation within ferrite phase grains. Similar fatigue fracture morphology with ovalization phenomenon was observed in all conditions. To predict the ratcheting fatigue life of aero-engine thin wall pipes, a validated fatigue life estimation model considering steady ratcheting displacement rate based on a finite element analysis (FEA) model was conducted, and all of the fatigue data are contained in a 1.1X scatter band.

Considerations in the Aging Female Athlete

As female athletes age, their risk of musculoskeletal injuries increases. These injuries can have a negative impact on their health and athletic abilities. This article explores the most common conditions that aging female athletes may face, such as osteoarthritis, meniscal injuries, joint instability, rotator cuff injuries, and stress fractures. Hormonal and physiological changes, anatomical differences, and changes in bone mineral density can cause these injuries. To prevent such injuries, it is crucial to incorporate comprehensive injury prevention programs that include strength training, flexibility exercises, balance training, and appropriate warm-up and cool-down routines. These programs should be tailored to the individual's fitness level and musculoskeletal issues. Additionally, the article offers valuable insights into various techniques for managing and treating these injuries, such as non-surgical interventions, surgical options, and rehabilitation programs. Healthcare professionals, coaches, and athletes themselves must recognize and address these issues to improve performance, prevent injuries, and support the overall health and well-being of aging female athletes. In conclusion, maintaining physical fitness and engaging in structured exercise programs are crucial for aging female athletes to slow the decline in musculoskeletal strength and integrity. Proper first aid measures, appropriate medications, and a comprehensive exercise regimen can aid in recovery and regain strength, function, and mobility, enabling a return to competitive sports or other athletic pursuits.