Comparing fracture healing disorders and long-term functional outcome of polytrauma patients and patients with an isolated displaced midshaft clavicle fracture.

PubMed

Ferree, Steven; Hietbrink, Falco; van der Meijden, Olivier A J; Verleisdonk, Egbert Jan M M; Leenen, Luke P H; Houwert, Roderick M

2017-01-01

Although clavicle fractures are a common injury in polytrauma patients, the functional outcome of displaced midshaft clavicle fractures (DMCFs) in this population is unknown. Our hypothesis was that there would be no differences in fracture healing disorders or functional outcome in polytrauma patients with a DMCF compared with patients with an isolated DMCF, regardless of the treatment modality. A retrospective cohort study of patients (treated at our level I trauma center) with a DMCF was performed and a follow-up questionnaire was administered. Polytrauma patients, defined as an Injury Severity Score ≥16, and those with an isolated clavicle fracture were compared. Fracture healing disorders (nonunion and delayed union) and delayed fixation rates were determined. Functional outcome was assessed by the Quick Disability of the Arm, Shoulder, and Hand questionnaire. A total of 152 patients were analyzed, 71 polytrauma patients and 81 patients with an isolated DMCF. Questionnaire response of 121 patients (80%) was available (mean, 53 months; standard deviation, 22 months). No differences were found between polytrauma patients and those with an isolated DMCF with regard to nonunion (7% vs. 5%, respectively), delayed union (4% vs. 4%), and delayed fixation rate (13% vs. 13%). Polytrauma patients had an overall worse functional outcome, regardless of initial nonoperative treatment or delayed operative fixation. Polytrauma patients had a similar nonunion and delayed fixation rate but had an overall worse functional outcome compared with patients with an isolated DMCF. For polytrauma patients, a wait and see approach can be advocated without the risk of decreased upper extremity function after delayed fixation. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Early Initial Antibiotics and Debridement Independently Reduce Infection in an Open Fracture Model

DTIC Science & Technology

2012-01-01

infection in those Gustilo-Anderson grade III fractures whose surgery was delayed until return to the US, compared with those who underwent early...LEAP) included a prospective observational study of 315 patients with Gustilo-Anderson grade III open fractures of the tibia, foot and ankle and, in...6. Ashford RU, Mehta JA, Cripps R. Delayed presentation is no barrier to satisfactory outcome in the management of open tibial fractures . Injury

The use of low-intensity pulsed ultrasound in treating delayed union of fifth metatarsal fractures.

PubMed

Teoh, Kar Hao; Whitham, Robert; Wong, Jenny F; Hariharan, Kartik

2018-01-31

There are no studies looking at the success rate of low-intensity pulsed ultrasound (LIPUS) in fifth metatarsal fracture delayed unions to our knowledge. The aim of this study is to investigate the use of LIPUS treatment for delayed union of fifth metatarsal fractures. A retrospective review of patients who were treated with LIPUS following a delayed union of fifth metatarsal fracture was conducted over a three-year period. There were thirty patients (9 males, 21 females) in this cohort. The average age was 39.3 years. Type 2 fractures made up 43% of our cohort. Twenty-seven (90%) patients went on to progress to union clinically and radiologically following LIPUS treatment. Smoking (p=0.014) was predictive of non-union. Assuming that there were 10 delayed unions a year and 6 went on to non-union as previously suggested by a systematic review, the cost savings of using LIPUS (90% success rate; 10 LIPUS machine and surgery for 1 non-union) vs operative intervention (surgery for 6 non-union) equates to a cost saving of £7765 a year. There is a role for the use of LIPUS in delayed union of fifth metatarsal fractures and can serve as an adjunct prior to consideration of surgery. The findings of this study also suggest the use of LIPUS to be a cost effective treatment modality compared to surgical management. Level 4. Copyright © 2018 Elsevier Ltd. All rights reserved.

[Comparison of effect between early and delayed in primary intramedullary nailing combined with locked plate fixation for the treatment of multi-segments tibial fractures of type].

PubMed

Gao, Wei-qiang; Hu, Jiang-hai; Gu, Zhu-chao; Zhang, Huai-xian; Min, Peng; Zhang, Lin-jun; Yu, Wen-wen; Wang, Guang-lin

2015-02-01

To compare the clinical results of early and delayed intramedullary nailing and locked plating for the treatment of multi-segments tibial fractures of type AO/ASIF-42C2. Between January 2010 and January 2013,45 patients with multi-segments closed tibial fractures of AO/ASIF-42C2 were treated by early primary intramedullary nailing and locked plating in 20 cases as early group and delayed in 25 cases as delayed group. In early group,20 cases included 13 males and 7 females with an average age of (37.9±14.3) years old ranging from 20 to 56 years;according to soft tissue injury Tscherne classification, 8 fractures were frade I,12 were grade II. In delayed group, 25 cases included 17 males and 8 females with an average age of (38.7±17.2) years old ranging from 24 to 55 years,4 fractures were grade I ,19 were grade II ,2 were grade III. The operative time, blood loss, hospital stay,fracture healing time and complications were recorded. At final follow-up, the Johner-Wruhs score were used to evaluate functional efficacy, and the posterior-anterior and lateral X-ray to evaluate fracture reduction and alignment. All the patients were followed up for (12.5±2.5) months in early group and (13.2±2.8) months in delayed group (P>0.05). No wounds infections were happened. At the last follow-up, the mean range of knee joint was 10°-0°-120°. According to Johner-Wruhs scoring,there were 15 cases in excellent,3 in good,fair in 2 in early group; 21 in excellent,2 in good,2 in fair. The average operative time,blood loss had no significant differences between two groups (P>0.05), but hospital stay in early group was significantly shorter than those in delayed group(P<0.05). Average fracture healing time of early group and delayed group were (5.3±2.6) months and (6.0±2.9) months, respectively (P>0.05). For multi-segments tibial fractures of type AO/ASIF-42C2 with preoperative minor soft tissue injuries lighter of Tscherne grade I or II, early primary intramedullary nailing and locked plating does not significantly increase the postoperative incidence of soft tissue complications for patients. The early and delayed primary intramedullary nailing and locked plating for treatment of AO/ASIF-42C2 proximal third tibial fractures can get similar curative effect.

Technical considerations to avoid delayed and non-union.

PubMed

McMillan, Tristan E; Johnstone, Alan J

2017-06-01

For many years intramedullary nails have been a well accepted and successful method of diaphyseal fracture fixation. However, delayed and non unions with this technique do still occur and are associated with significant patient morbidity. The reason for this can be multi-factorial. We discuss a number of technical considerations to maximise fracture reduction, fracture stability and fracture vascularity in order to achieve bony union. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

Open reduction of nasal bone fractures through an intercartilaginous incision.

PubMed

Kim, Ji Heui; Lee, Jun Ho; Hong, Seok Min; Park, Chan Hum

2013-01-01

Open reduction through an intercartilaginous incision was useful for treating delayed-diagnosed nasal bone fractures because it resulted in a successful outcome with minimal complications. Nasal bone fractures are generally managed with closed reduction, which is usually inadequate and results in airway obstruction with a delayed diagnosis of nasal bone fracture when bone healing and fibrotic adhesions around the bone fragment have progressed. This study investigated the surgical outcome of open reduction through an intercartilaginous incision for delayed-diagnosis nasal bone fractures. The study enrolled 18 patients who underwent open reduction through an intercartilaginous incision to correct delayed-diagnosis nasal bone fractures. Three independent otorhinolaryngologists evaluated the outcomes 4-35 months (average 12.7 months) postoperatively as excellent, fair or poor. The time from injury to surgery was 11-39 days (20-39 days in adults and 11-30 days in children). The 18 cases included 16 primary repairs and two revisions. A Kirschner wire was inserted in six (33.3%) patients who had unstable reduced nasal bones. Postoperatively, l5 (83%) patients had excellent results, two (11%) had fair, and one (6%) had a poor outcome. No patient experienced any complication.

Comparison of Early and Delayed Open Reduction and Internal Fixation for Treating Closed Tibial Pilon Fractures.

PubMed

Tang, Xin; Liu, Lei; Tu, Chong-qi; Li, Jian; Li, Qi; Pei, Fu-xing

2014-07-01

The timing of surgery for osteosynthesis of type C pilon (AO/OTA) fractures remains controversial. The aim of this study was to determine the outcome of early and delayed open reduction and internal fixation (ORIF) for treating closed type C pilon fractures. Forty-six patients with closed type C pilon fractures matched according to age, gender, soft tissue conditions, and fracture pattern were divided into group A (early group: underwent surgery within 36 hours of the injury) or group B (delayed group: underwent surgery 10 days to 3 weeks postinjury after the soft tissue swelling subsided). In the delayed group, 9 patients were treated first by temporary external fixation. All the closed fractures were managed by ORIF with locking plates. At follow-up, the clinical and radiographic results were retrospectively analyzed. The mean follow-up time was 25.8 months (range, 14 to 48 months) in group A and 26.0 months (range, 15 to 44 months) in group B. There was no significant difference (P > .05) between the 2 groups regarding the rate of soft tissue complication, the rate of fracture union, and the final functional score. The patients in group A had a significantly shorter mean time to fracture union (21.5 ± 4.0 weeks vs 23.3 ± 3.7 weeks, P < .05), operating time (84.3 ± 12.1 months vs 100.6 ± 13.7 months, P < .01), and hospital stay (7.6 ± 2.6 days vs 15.2 ± 4.2 days, P < .01). If soft tissue conditions are acceptable, early ORIF for treating closed type C pilon fractures can be safe and effective, with similar rates of wound complication, fracture union, and final good functional recovery but shorter operative time, union time, and hospital stay. These results favorably compare with delayed ORIF treatment. Level III, retrospective comparative study. © The Author(s) 2014.

Manubriosternal dislocation with spinal fracture: A rare cause for delayed haemothorax.

PubMed

Kothari, Manish; Saini, Pramod; Shethna, Sunny; Dalvie, Samir

2015-01-01

Type 2 manubriosternal dislocations with concomitant spinal fracture are rare and may be associated with thoracic visceral injuries. The complication of delayed haemothorax has not been reported yet. We report a case of a young male who suffered manubriosternal dislocation with chance type thoracic spine fracture due to fall of a tree branch over his back. The haemothorax presented late on day three. The possible injury mechanism is discussed along with review of literature. We conclude that a lateral chest radiograph is indicated in spinal fracture patients complaining of midsternal pain. Computerized axial tomography scan of chest with contrast is indicated to rule out visceral injuries and a chest radiograph should be repeated before the patient is discharged to look for delayed haemothorax.

Complications of ankle fracture in patients with diabetes.

PubMed

Chaudhary, Saad B; Liporace, Frank A; Gandhi, Ankur; Donley, Brian G; Pinzur, Michael S; Lin, Sheldon S

2008-03-01

Ankle fractures in patients with diabetes mellitus have long been recognized as a challenge to practicing clinicians. Complications of impaired wound healing, infection, malunion, delayed union, nonunion, and Charcot arthropathy are prevalent in this patient population. Controversy exists as to whether diabetic ankle fractures are best treated noninvasively or by open reduction and internal fixation. Patients with diabetes are at significant risk for soft-tissue complications. In addition, diabetic ankle fractures heal, but significant delays in bone healing exist. Also, Charcot ankle arthropathy occurs more commonly in patients who were initially undiagnosed and had a delay in immobilization and in patients treated nonsurgically for displaced ankle fractures. Several techniques have been described to minimize complications associated with diabetic ankle fractures (eg, rigid external fixation, use of Kirschner wires or Steinmann pins to increase rigidity). Regardless of the specifics of treatment, adherence to the basic principles of preoperative planning, meticulous soft-tissue management, and attention to stable, rigid fixation with prolonged, protected immobilization are paramount in minimizing problems and yielding good functional outcomes.

Delayed retropubic urethroplasty of completely transected urethra associated with pelvic fracture in girls.

PubMed

Hosseini, Jalil; Tavakkoli Tabassi, Kamyar; Razi, Abdollah

2009-01-01

The objective of the present study was to evaluate the results and the complications of delayed retropubic urethroplasty of completely transected urethra associated with pelvic fracture in girls. From 2002 to 2008, a total of 7 girls with complete urethral disruption after pelvic fracture were referred to our center and all of them underwent delayed retropubic urethroplasty with end-to-end anastomosis of the urethra. Seven female patients with a median age of 6 years old underwent delayed end-to-end anastomosis. The median time to surgery was 6 months from the trauma. Voiding was normal after catheter removal in all of the patients. The median follow-up was 36 months. Three patients had mild stress urinary incontinence after catheter removal. There are some different strategies for management of complete urethral avulsion in females who have sustained pelvic fracture, including early realignment, bladder flaps, and end-to-end anastomosis. The strategy of delayed end-to-end anastomosis urethroplasty with retropubic approach is sound and produces acceptable results. The use of flexible cystoscope and omental flap is effective in achieving continence after urethroplasty in such cases.

PTH 1-34 Ameliorates the Osteopenia and Delayed Healing of Stabilized Tibia Fracture in Mice with Achondroplasia Resulting from Gain-Of-Function Mutation of FGFR3

PubMed Central

Chen, Hangang; Sun, Xianding; Yin, Liangjun; Chen, Shuai; Zhu, Ying; Huang, Junlan; Jiang, Wanling; Chen, Bo; Zhang, Ruobin; Chen, Lin; Nie, Mao; Xie, Yangli; Deng, Zhongliang

2017-01-01

Bone fracture healing is processed through multiple stages including the cartilaginous callus formation and its transition to bony callus. FGFR3 negatively regulates chondrogenesis and enhances osteogenesis during skeleton development. We previously found in mice carrying gain-of-function mutation of FGFR3 that FGFR3 delays the healing of un-stabilized fracture that heals mainly through endochondral ossification. Since fracture is regularly treated in clinics with rigid fixation, and stabilized fracture is healed largely through intramembranous ossification, we asked whether FGFR3, a key regulator of osteogenesis, also affect the regeneration of stabilized fracture. We found that gain-of-function mutation of FGFR3 inhibits the initiation of chondrogenesis and the subsequent bone formation. We further studied whether PTH1-34 can improve the osteopenia and delayed healing of the stabilized tibia fracture in mice with achondroplasia. Fracture healing was evaluated by radiography, micro-CT, biomechanical tests, histology, and real-time polymerase chain reaction (RT-PCR) analysis. We found that PTH 1-34 can alleviate the decreased bone mass and compromised architecture in ACH mice. Histological analysis revealed that administration of PTH1-34 increased the size of both the total callus and cartilaginous callus at 14 days after the surgery in ACH mice. RT-PCR data suggested that systemic PTH1-34 accelerated the initiation of chondrogenesis and chondrocyte maturation (earlier and higher levels of expression of chondrogenesis related markers) and enhanced the osteogenic differentiation in the fracture callus in ACH mice. These results indicate that the PTH1-34 administration resulted in an enhanced callus formation during bone fracture healing in ACH mice, which is at least in part mediated by an increase of cartilaginous callus at early stage and the promotion of bone formation in bony callus. In summary, in this study we revealed that FGFR3 delays the regeneration of stabilized fracture by inhibiting both the chondrogenesis and osteogenesis, and PTH1-34 treatment can improve the dysregulated bone metabolism and delayed bone injury healing resulting from gain-of-function mutation of FGFR3. PMID:29104492

2014 Accomplishments-Tritium aging studies on stainless steel: Fracture toughness properties of forged stainless steels-Effect of hydrogen, forging strain rate, and forging temperature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morgan, Michael J.

Forged stainless steels are used as the materials of construction for tritium reservoirs. During service, tritium diffuses into the reservoir walls and radioactively decays to helium-3. Tritium and decay helium cause a higher propensity for cracking which could lead to a tritium leak or delayed failure of a tritium reservoir. The factors that affect the tendency for crack formation and propagation include: Environment; steel type and microstructure; and, vessel configuration (geometry, pressure, residual stress). Fracture toughness properties are needed for evaluating the long-term effects of tritium on their structural properties. Until now, these effects have been characterized by measuring themore » effects of tritium on the tensile and fracture toughness properties of specimens fabricated from experimental forgings in the form of forward-extruded cylinders. A key result of those studies is that the long-term cracking resistance of stainless steels in tritium service depends greatly on the interaction between decay helium and the steels’ forged microstructure. New experimental research programs are underway and are designed to measure tritium and decay helium effects on the cracking properties of stainless steels using actual tritium reservoir forgings instead of the experimental forgings of past programs. The properties measured should be more representative of actual reservoir properties because the microstructure of the specimens tested will be more like that of the tritium reservoirs. The programs are designed to measure the effects of key forging variables on tritium compatibility and include three stainless steels, multiple yield strengths, and four different forging processes. The effects on fracture toughness of hydrogen and crack orientation were measured for type 316L forgings. In addition, hydrogen effects on toughness were measured for Type 304L block forgings having two different yield strengths. Finally, fracture toughness properties of type 304L stainless steel were measured for four different forging strain rates which and two forging temperatures. Tritium exposures have been and are being conducted on companion specimens for property measurements in the upcoming years.« less

Diabetes mellitus affects the biomechanical function of the callus and the expression of TGF-beta1 and BMP2 in an early stage of fracture healing.

PubMed

Xu, M T; Sun, S; Zhang, L; Xu, F; Du, S L; Zhang, X D; Wang, D W

2016-01-01

Transforming growth factor beta 1 (TGF-β1) and bone morphogenetic protein-2 (BMP-2) are important regulators of bone repair and regeneration. In this study, we examined whether TGF-β1 and BMP-2 expressions were delayed during bone healing in type 1 diabetes mellitus. Tibial fractures were created in 95 diabetic and 95 control adult male Wistar rats of 10 weeks of age. At 1, 2, 3, 4, and 5 weeks after fracture induction, five rats were sacrificed from each group. The expressions of TGF-β1 and BMP2 in the fractured tibias were measured by immunohistochemistry and quantitative reverse-transcription polymerase chain reaction, weekly for the first 5 weeks post-fracture. Mechanical parameters (bending rigidity, torsional rigidity, destruction torque) of the healing bones were also assessed at 3, 4, and 5 weeks post-fracture, after the rats were sacrificed. The bending rigidity, torsional rigidity and destruction torque of the two groups increased continuously during the healing process. The diabetes group had lower mean values for bending rigidity, torsional rigidity and destruction torque compared with the control group (P<0.05). TGF-β1 and BMP-2 expression were significantly lower (P<0.05) in the control group than in the diabetes group at postoperative weeks 1, 2, and 3. Peak levels of TGF-β1 and BMP-2 expression were delayed by 1 week in the diabetes group compared with the control group. Our results demonstrate that there was a delayed recovery in the biomechanical function of the fractured bones in diabetic rats. This delay may be associated with a delayed expression of the growth factors TGF-β1 and BMP-2.

Delayed pneumothorax complicating minor rib fracture after chest trauma.

PubMed

Lu, Ming-Shian; Huang, Yao-Kuang; Liu, Yun-Hen; Liu, Hui-Ping; Kao, Chiung-Lun

2008-06-01

Pneumothorax (PTX) after trauma is a preventable cause of death. Drainage procedures such as chest tube insertion have been traditionally advocated to prevent fatal tension PTX. We evaluated the safety of close observation in patients with delayed PTX complicating rib fracture after minor chest trauma. Adult patients (>18 years) with a diagnosis of chest trauma and 3 or fewer fractured ribs were reviewed. Case patients were divided according to age, location and number of fractured ribs, mechanism of trauma, and initial pulmonary complication after thoracic trauma for comparative analysis. There were 207 male (70.2%) and 88 female (29.8%) patients whose ages ranged from 18 to 93 years (median, 55 years). The mechanisms of trauma were a motor vehicle accident in 207 patients, falls in 66, pedestrian injury in 10, and assaults in 14. Ninety-five patients sustained 1 rib fracture, 95 had 2 rib fractures, and 105 suffered 3 rib fractures. Right-sided injury occurred in 164 cases, left-sided injury did in 127, and bilateral injury did in 4. The most frequent location of rib fractures was from the fourth rib to the ninth rib. The initial pulmonary complications after trauma were PTX in 16 patients, hemothorax in 43, pneumohemothorax in 14, lung contusion in 75, and isolated subcutaneous emphysema (SubcEmph) in 33. Thirty percent of the patients (n = 5/16) who presented with traumatic PTX were observed safely without drainage. Delayed PTX was recorded in 16 patients, occurring mostly during the first 2 days of their admission. Associated extrathoracic injury was recorded in 189 patients. The mean hospital stay of the patients was 7.66 days. Longer hospital stay was related to increasing number of fractured ribs, need for thoracic drainage, and the presence of associated extrathoracic injury. The mortality rate for the entire group was 2%. The presence of SubcEmph was the only risk factor associated with the development of delayed PTX. Patients sustaining blunt chest trauma and minor rib fractures should be admitted for close observation when presenting with SubcEmph because of possible delayed presentation of PTX.

Delay in weight bearing in surgically treated tibial shaft fractures is associated with impaired healing: a cohort analysis of 166 tibial fractures.

PubMed

Houben, I B; Raaben, M; Van Basten Batenburg, M; Blokhuis, T J

2018-04-09

The relation between timing of weight bearing after a fracture and the healing outcome is yet to be established, thereby limiting the implementation of a possibly beneficial effect for our patients. The current study was undertaken to determine the effect of timing of weight bearing after a surgically treated tibial shaft fracture. Surgically treated diaphyseal tibial fractures were retrospectively studied between 2007 and 2015. The timing of initial weight bearing (IWB) was analysed as a predictor for impaired healing in a multivariate regression. Totally, 166 diaphyseal tibial fractures were included, 86 cases with impaired healing and 80 with normal healing. The mean age was 38.7 years (range 16-89). The mean time until IWB was significantly shorter in the normal fracture healing group (2.6 vs 7.4 weeks, p < 0.001). Correlation analysis yielded four possible confounders: infection requiring surgical intervention, fracture type, fasciotomy and open fractures. Logistic regression identified IWB as an independent predictor for impaired healing with an odds ratio of 1.13 per week delay (95% CI 1.03-1.25). Delay in initial weight bearing is independently associated with impaired fracture healing in surgically treated tibial shaft fractures. Unlike other factors such as fracture type or soft tissue condition, early resumption of weight bearing can be influenced by the treating physician and this factor therefore has a direct clinical relevance. This study indicates that early resumption of weight bearing should be the treatment goal in fracture fixation. 3b.

Models of tibial fracture healing in normal and Nf1-deficient mice.

PubMed

Schindeler, Aaron; Morse, Alyson; Harry, Lorraine; Godfrey, Craig; Mikulec, Kathy; McDonald, Michelle; Gasser, Jürg A; Little, David G

2008-08-01

Delayed union and nonunion are common complications associated with tibial fractures, particularly in the distal tibia. Existing mouse tibial fracture models are typically closed and middiaphyseal, and thus poorly recapitulate the prevailing conditions following surgery on a human open distal tibial fracture. This report describes our development of two open tibial fracture models in the mouse, where the bone is broken either in the tibial midshaft (mid-diaphysis) or in the distal tibia. Fractures in the distal tibial model showed delayed repair compared to fractures in the tibial midshaft. These tibial fracture models were applied to both wild-type and Nf1-deficient (Nf1+/-) mice. Bone repair has been reported to be exceptionally problematic in human NF1 patients, and these patients can also spontaneously develop tibial nonunions (known as congenital pseudarthrosis of the tibia), which are recalcitrant to even vigorous intervention. pQCT analysis confirmed no fundamental differences in cortical or cancellous bone in Nf1-deficient mouse tibiae compared to wild-type mice. Although no difference in bone healing was seen in the tibial midshaft fracture model, the healing of distal tibial fractures was found to be impaired in Nf1+/- mice. The histological features associated with nonunited Nf1+/- fractures were variable, but included delayed cartilage removal, disproportionate fibrous invasion, insufficient new bone anabolism, and excessive catabolism. These findings imply that the pathology of tibial pseudarthrosis in human NF1 is complex and likely to be multifactorial.

Are the current guidelines for surgical delay in hip fractures too rigid? A single center assessment of mortality and economics.

PubMed

Kempenaers, Kristof; Van Calster, Ben; Vandoren, Cindy; Sermon, An; Metsemakers, Willem-Jan; Vanderschot, Paul; Misselyn, Dominique; Nijs, Stefaan; Hoekstra, Harm

2018-06-01

Controversy remains around acceptable surgical delay of acute hip fractures with current guidelines ranging from 24 to 48 h. Increasing healthcare costs force us to consider the economic burden as well. We aimed to evaluate the adjusted effect of surgical delay for hip fracture surgery on early mortality, healthcare costs and readmission rate. We hypothesized that shorter delays resulted in lower early mortality and costs. In this retrospective cohort study 2573 consecutive patients aged ≥50 years were included, who underwent surgery for acute hip fractures between 2009 and 2017. Main endpoints were thirty- and ninety-day mortality, total cost, and readmission rate. Multivariable regression included sex, age and ASA score as covariates. Thirty-day mortality was 5% (n = 133), ninety-day mortality 12% (n = 304). Average total cost was €11960, dominated by hospitalization (59%) and honoraria (23%). Per 24 h delay, the adjusted odds ratio was 1.07 (95% CI 0.98-1.18) for thirty-day mortality, 1.12 (95% CI 1.04-1.19) for ninety-day mortality, and 0.99 (95% CI = 0.88-1.12) for readmission. Per 24 h delay, costs increased with 7% (95% CI 6-8%). For mortality, delay was a weaker predictor than sex, age, and ASA score. For costs, delay was the strongest predictor. We did not find clear cut-points for surgical delay after which mortality or costs increased abruptly. Despite only modest associations with mortality, we observed a steady increase in healthcare costs when delaying surgery. Hence, a more pragmatic approach with surgery as soon as medically and organizationally possible seems justifiable over rigorous implementation of the current guidelines. Copyright © 2018 Elsevier Ltd. All rights reserved.

Delayed surgical repair of penile fracture under local anesthesia.

PubMed

Nasser, Taha Abdel; Mostafa, Taymour

2008-10-01

Penile fracture is a traumatic rupture of the tunica albuginea because of blunt injury of an erect penis. To assess the efficacy of a simple delayed surgical repair of penile fracture after a conservative treatment under local anesthesia in patients presented after 24 hours. Twenty-four patients with penile fracture presented after 24 hours were subjected to history taking, clinical examination, urine analysis, and penile ultrasound. They underwent conservative treatment for 7-12 days, and then a surgical repair under local anesthesia was carried out. A follow-up for 6 months for sexual activity and any associated complaints in addition to local examination. All cases were presented with unilateral single tear, and the main cause of penile fracture was sexual intercourse. No intraoperative or postoperative complications were encountered. They regained their sexual activity 4-6 weeks after the repair. One case developed a mild penile deviation that did not interfere with sexual relation after the 6-month follow-up. Surgical repair of penile fracture after a conservative treatment is an effective method for patients with delayed presentation devoid of urethral involvement.

The effects of different nutritional measurements on delayed wound healing after hip fracture in the elderly.

PubMed

Guo, Jiong Jiong; Yang, Huilin; Qian, Haixin; Huang, Lixin; Guo, Zhongxing; Tang, Tiansi

2010-03-01

It has been well recognized that malnutrition causes wounds to heal inadequately and incompletely. Malnutrition is often observed in the elderly, and it appears to be more severe in patients with hip fracture than in the general aging population. Few prospective studies give a detailed account of the identification and classification of nutritional status in the elderly. The objective of this study was to evaluate the effects of different nutritional measurements on wound healing status after hip fracture in the elderly. From September 2002 to December 2007, 207 hip fracture patients older than 60 y treated surgically were reviewed for preoperative nutritional status. There were 81 males and 126 females with an average age of 75.93 y (62-91 y); 131 cases with femoral neck fractures, 76 cases with intertrochanteric fractures. Parameters indicative of nutritional status (serum albumin, serum transferrin, serum pre-albumin, and total lymphocyte count levels) at the time of admission were assessed, along with anthropometric measurements, Rainey MacDonald nutritional index, and MNA tool. Suture removal was performed on postoperative day 14. Delayed wound healing complicated 46 (22.2%) of the 207 cases. The preoperative serum transferring total lymphocyte count levels, MNA total score, and Rainey MacDonald nutritional index were significantly lower for patients who subsequently had delayed wound healing. When all variables were subjected to multivariate analysis, only total lymphocyte count levels and MNA total score showed significant value in predicting which patients would have delayed wound healing. Through prophylactic antibiotics and adherence to strict aseptic precautions, on follow-up, wound healing was normal in all patients. Patients at risk for delayed wound healing problems after hip fracture can be identified using relatively inexpensive laboratory test such as TLC and MNA tool. The clinician must be aware of the risk values of both measurements. We believe this information is particularly important before planning procedures of hip fractures in the elderly. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Delayed onset porous polyethylene implant-related inflammation after orbital blowout fracture repair: four case reports.

PubMed

Aryasit, Orapan; Ng, Danny S; Goh, Alice S C; Woo, Kyung In; Kim, Yoon-Duck

2016-07-07

Porous polyethylene implants are commonly used in orbital blowout fracture repair because of purported biocompatibility, durability, and low frequency of complications. Delayed inflammation related to porous polyethylene sheet implants is very rare and no case series of this condition have been reported. This is a retrospective review of clinical presentations, radiographic findings, histopathological findings, treatments, and outcomes of patients who developed delayed complications in orbital blowout fracture repair using porous polyethylene sheets. Four male patients were included with a mean age of 49 years (range 35-69 years). Blowout fracture repair was complicated with implant-related inflammation 10 months, 2 years, 3 years, and 8 years after surgery. Chronic and subacute orbital inflammatory signs were noted in two patients and acute fulminant orbital inflammation was found in two patients. Three patients developed peri-implant abscesses and one patient had a soft tissue mass around the implant. All patients underwent implant removal and two of these patients with paranasal sinusitis had sinus surgery. Histopathological findings revealed chronic inflammatory changes with fibrosis, and one patient had foreign body granuloma with culture positive Staphylococcus aureus. Delayed complications with porous polyethylene sheets used in orbital blowout fracture repair may occur many years following the initial surgery in immunocompetent patients. Low-grade or fulminant inflammation could complicate blowout fracture repair related with the implant.

Delayed Anterior Cruciate Ligament Reconstruction in Young Patients With Previous Anterior Tibial Spine Fractures.

PubMed

Mitchell, Justin J; Mayo, Meredith H; Axibal, Derek P; Kasch, Anthony R; Fader, Ryan R; Chadayammuri, Vivek; Terhune, E Bailey; Georgopoulos, Gaia; Rhodes, Jason T; Vidal, Armando F

2016-08-01

Avulsion fractures of the anterior tibial spine in young athletes are injuries similar to anterior cruciate ligament (ACL) injuries in adults. Sparse data exist on the association between anterior tibial spine fractures (ATSFs) and later ligamentous laxity or injuries leading to ACL reconstruction. To better delineate the incidence of delayed instability or ACL ruptures requiring delayed ACL reconstruction in young patients with prior fractures of the tibial eminence. Case series; Level of evidence, 4. We identified 101 patients between January 1993 and January 2012 who sustained an ATSF and who met inclusion criteria for this study. All patients had been followed for at least 2 years after the initial injury and were included for analysis after completion of a questionnaire via direct contact, mail, and/or telephone. If patients underwent further surgical intervention and/or underwent later ACL reconstruction, clinical records and operative reports pertaining to these secondary interventions were obtained and reviewed. Differences between categorical variables were assessed using the Fisher exact test. The association between time to revision ACL surgery and fracture type was assessed by Kaplan-Meier plots. The association between need for revision ACL surgery and age, sex, and mechanism of surgery was assessed using logistic regression. Nineteen percent of all patients evaluated underwent delayed ACL reconstruction after a previous tibial spine fracture on the ipsilateral side. While there were a higher proportion of ACL reconstructions in type II fractures, there was not a statistically significant difference in the number of patients within each fracture group who went on to undergo later surgery (P = .29). Further, there was not a significant association between fracture type, sex, or mechanism of injury as it related to the progression to later ACL reconstruction. However, there was a significant association between age at the time of injury and progression to later ACL reconstruction (P = .02). For every year increase in age at the time of injury, the odds of going on to undergo delayed ACL reconstruction were greater by a factor of 1.3 (95% CI, 1.1-1.6). Although an ATSF is a relatively rare injury, our cohort of patients suggests that a subset of young patients with all types of tibial spine fractures will require later ACL reconstruction. There is a need to counsel patients that a delayed ACL rupture is a potential risk after an ATSF, especially as children approach skeletal maturity. Further patient follow-up and prospective studies are required. © 2016 The Author(s).

Delayed Union of a Sacral Fracture: Percutaneous Navigated Autologous Cancellous Bone Grafting and Screw Fixation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huegli, R. W.; Messmer, P.; Jacob, A. L.

2003-09-15

Delayed or non-union of a sacral fracture is a serious clinical condition that may include chronic pain, sitting discomfort, gait disturbances, neurological problems, and inability to work. It is also a difficult reconstruction problem. Late correction of the deformity is technically more demanding than the primary treatment of acute pelvic injuries. Open reduction, internal fixation (ORIF), excision of scar tissue, and bone grafting often in a multi-step approach are considered to be the treatment of choice in delayed unions of the pelvic ring. This procedure implies the risk of neurological and vascular injuries, infection, repeated failure of union, incomplete correctionmore » of the deformity, and incomplete pain relief as the most important complications. We report a new approach for minimally invasive treatment of a delayed union of the sacrum without vertical displacement. A patient who suffered a Malgaigne fracture (Tile C1.3) was initially treated with closed reduction and percutaneous screw fixation (CRPF) of the posterior pelvic ring under CT navigation and plating of the anterior pelvic ring. Three months after surgery he presented with increasing hip pain caused by a delayed union of the sacral fracture. The lesion was successfully treated percutaneously in a single step procedure using CT navigation for drilling of the delayed union, autologous bone grafting, and screw fixation.« less

[Case-control study on transverse carpal ligament resection for the prevention of delayed carpal tunnel syndrome after distal radius fracture].

PubMed

Wang, Yan-jie; Wang, Shi-gang; Miao, Shu-juan; Su, Xia

2011-06-01

To investigate the effects of open reduction by palm side for the distal radius fracture and T shape plate internal fixation with simultaneous anterior transverse carpal ligament resection for the prevention of delayed carpal tunnel syndrome after operation. From March 2000 to March 2007, 32 patients (8 males and 24 females, ranging in age from 46 to 66 years) with distal radius fracture were treated with open reduction by palm side and T shape plate internal fixation with simultaneous anterior transverse carpal ligament resection; while 30 patients (7 males and 23 females,ranging in age from 45 to 65 years) only with open reduction by palm side and T shape plate internal fixation. The incidences of delayed carpal tunnel syndrome between the two groups were compared. Among 32 patients treated with open reduction by palm side and T shape plate internal fixation with anterior transverse carpal ligament resection, 3 patients had delayed carpal tunnel syndrome; while in 30 patients treated with open reduction by palm side and T shape plate internal fixation, 10 patients had delayed carpal tunnel syndrome. There was significant statistically difference (P < 0.05%). Simultaneous anterior transverse carpal ligament resection can effectively prevent the delayed carpal tunnel syndrome occurrence for the distal radius fracture with open reduction by palm side.

Multiple Low Energy Long Bone Fractures in the Setting of Rothmund-Thomson Syndrome.

PubMed

Beckmann, Nicholas

2015-01-01

Rothmund-Thomson syndrome is a rare autosomal recessive genodermatosis characterized by a poikilodermatous rash starting in infancy as well as various skeletal anomalies, juvenile cataracts, and predisposition to certain cancers. Although Rothmund-Thomson syndrome is associated with diminished bone mineral density in addition to multiple skeletal abnormalities, there are few reports of the association with stress fractures or pathologic fractures in low energy trauma or delayed healing of fractures. Presented is a case of a young adult male with Rothmund-Thomson syndrome presenting with multiple episodes of long bone fractures caused by low energy trauma with one of the fractures exhibiting significantly delayed healing. The patient was also found to have an asymptomatic stress fracture of the lower extremity, another finding of Rothmund-Thomson syndrome rarely reported in the literature. A thorough review of the literature and comprehensive presentation of Rothmund-Thomson syndrome is provided in conjunction with our case.

Effect of Nb on Delayed Fracture Resistance of Ultra-High Strength Martensitic Steels

NASA Astrophysics Data System (ADS)

Song, Rongjie; Fonstein, Nina; Pottore, Narayan; Jun, Hyun Jo; Bhattacharya, Debanshu; Jansto, Steve

Ultra-high strength steels are materials of considerable interest for automotive and structural applications and are increasingly being used in those areas. Higher strength, however, makes steels more prone to hydrogen embrittlement (HE). The effects of Nb and other alloying elements on the hydrogen-induced delayed fracture resistance of cold rolled martensitic steels with ultra-high strength 2000 MPa were studied using an acid immersion test, thermal desorption analysis (TDA) and measuring of permeation. The microstructure was characterized by high resolution field emission Scanning Electron Microscopy (SEM) with Electron Backscattered Diffraction (EBSD) and Transmission Electron Microscopy (TEM). It was shown that the combined addition of Nb significantly improved the delayed fracture resistance of investigated steel. The addition of Nb to alloyed martensitic steels resulted in very apparent grain refinement of the prior austenite grain size. The Nb microalloyed steel contained a lower diffusible hydrogen content during thermal desorption analysis as compared to the base steel and had a higher trapped hydrogen amount after charging. The reason that Nb improved the delayed fracture resistance of steels can be attributed mostly to both hydrogen trapping and grain refinement.

Do biodegradable magnesium alloy intramedullary interlocking nails prematurely lose fixation stability in the treatment of tibial fracture? A numerical simulation.

PubMed

Wang, Haosen; Hao, Zhixiu; Wen, Shizhu

2017-01-01

Intramedullary interlocking nailing is an effective technique used to treat long bone fractures. Recently, biodegradable metals have drawn increased attention as an intramedullary interlocking nailing material. In this study, numerical simulations were implemented to determine whether the degradation rate of magnesium alloy makes it a suitable material for manufacturing biodegradable intramedullary interlocking nails. Mechano-regulatory and bone-remodeling models were used to simulate the fracture healing process, and a surface corrosion model was used to simulate intramedullary rod degradation. The results showed that magnesium alloy intramedullary rods exhibited a satisfactory degradation rate; the fracture healed and callus enhancement was observed before complete dissolution of the intramedullary rod. Delayed magnesium degradation (using surface coating techniques) did not confer a significant advantage over the non-delayed degradation process; immediate degradation also achieved satisfactory healing outcomes. However, delayed degradation had no negative effect on callus enhancement, as it did not cause signs of stress shielding. To avoid risks of individual differences such as delayed union, delayed degradation is recommended. Although the magnesium intramedullary rod did not demonstrate rapid degradation, its ability to provide high fixation stiffness to achieve earlier load bearing was inferior to that of the conventional titanium alloy and stainless steel rods. Therefore, light physiological loads should be ensured during the early stages of healing to achieve bony healing; otherwise, with increased loading and degraded intramedullary rods, the fracture may ultimately fail to heal. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fractures Due to Gunshot Wounds: Do Retained Bullet Fragments Affect Union?

PubMed

Riehl, John T; Connolly, Keith; Haidukewych, George; Koval, Ken

2015-01-01

Many types of projectiles, including modern hollow point bullets, fragment into smaller pieces upon impact, particularly when striking bone. This study was performed to examine the effect on time to union with retained bullet material near a fracture site in cases of gunshot injury. All gunshot injuries operatively treated with internal fixation at a Level 1 Trauma Center between March 2008 and August 2011 were retrospectively reviewed. Retained bullet load near the fracture site was calculated based on percentage of material retained compared to the cortical diameter of the involved bone. Analyses were performed to assess the effect of the lead-cortical ratio and amount of comminution on time to fracture union. Thirty-two patients (34 fractures) met the inclusion criteria, with an equal number of comminuted (17) and non-comminuted fractures (17). Seventeen of 34 fractures (50%) united within 4 months, 16/34 (47%) developed a delayed union, and 1/34 (3%) developed a nonunion requiring revision surgery. Sixteen of 17 fractures (94%) that united by 4 months had a cumulative amount of bullet fragmentation retained near the fracture site of less than 20% of the cortical diameter. Nine out of 10 fractures (90%) with retained fragments near the fracture site was equal to or exceeding 20% of the cortical diameter had delayed or nonunion. Fracture comminution had no effect on time to union. The quantity of retained bullet material near the fracture site was more predictive of the rate of fracture union than was comminution. Fractures with bullet fragmentation equal to or exceeding 20% of the cortical width demonstrated a significantly higher rate of delayed union/nonunion compared to those fractures with less retained bullet material, which may indicate a local cytotoxic effect from lead on bone healing. These findings may influence decisions on timing of secondary surgeries. Level III.

Fractures Due to Gunshot Wounds: Do Retained Bullet Fragments Affect Union?

PubMed Central

Riehl, John T.; Connolly, Keith; Haidukewych, George; Koval, Ken

2015-01-01

Background Many types of projectiles, including modern hollow point bullets, fragment into smaller pieces upon impact, particularly when striking bone. This study was performed to examine the effect on time to union with retained bullet material near a fracture site in cases of gunshot injury. Methods All gunshot injuries operatively treated with internal fixation at a Level 1 Trauma Center between March 2008 and August 2011 were retrospectively reviewed. Retained bullet load near the fracture site was calculated based on percentage of material retained compared to the cortical diameter of the involved bone. Analyses were performed to assess the effect of the lead-cortical ratio and amount of comminution on time to fracture union. Results Thirty-two patients (34 fractures) met the inclusion criteria, with an equal number of comminuted (17) and non-comminuted fractures (17). Seventeen of 34 fractures (50%) united within 4 months, 16/34 (47%) developed a delayed union, and 1/34 (3%) developed a nonunion requiring revision surgery. Sixteen of 17 fractures (94%) that united by 4 months had a cumulative amount of bullet fragmentation retained near the fracture site of less than 20% of the cortical diameter. Nine out of 10 fractures (90%) with retained fragments near the fracture site was equal to or exceeding 20% of the cortical diameter had delayed or nonunion. Fracture comminution had no effect on time to union. Conclusions The quantity of retained bullet material near the fracture site was more predictive of the rate of fracture union than was comminution. Fractures with bullet fragmentation equal to or exceeding 20% of the cortical width demonstrated a significantly higher rate of delayed union/nonunion compared to those fractures with less retained bullet material, which may indicate a local cytotoxic effect from lead on bone healing. These findings may influence decisions on timing of secondary surgeries. Level of Evidence Level III PMID:26361445

A new experimental method for the accelerated characterization of composite materials

NASA Technical Reports Server (NTRS)

Brinson, H. F.; Morris, D. H.; Yeow, Y. T.

1978-01-01

A method which permits the prediction of long-term properties of graphite/epoxy laminates on the basis of short-term (15 min) laboratory tests is described. Demonstration of delayed viscoelastic fracture in one laminate configuration, and data on the time and temperature response of a matrix-dominated unidirectional laminate contributed to a characterization of the viscoelastic process in the graphite/epoxy composites. Master curves from short-term tests of certain laminate configurations can be employed to generate long-term master curves. In addition, analytical predictions from short-term results can be used to predict long-term (25-hour) laminate properties.

External fixation of tibial pilon fractures and fracture healing.

PubMed

Ristiniemi, Jukka

2007-06-01

Distal tibial fractures are rare and difficult to treat because the bones are subcutaneous. External fixation is commonly used, but the method often results in delayed union. The aim of the present study was to find out the factors that affect fracture union in tibial pilon fractures. For this purpose, prospective data collection of tibial pilon fractures was carried out in 1998-2004, resulting in 159 fractures, of which 83 were treated with external fixation. Additionally, 23 open tibial fractures with significant > 3 cm bone defect that were treated with a staged method in 2000-2004 were retrospectively evaluated. The specific questions to be answered were: What are the risk factors for delayed union associated with two-ring hybrid external fixation? Does human recombinant BMP-7 accelerate healing? What is the role of temporary ankle-spanning external fixation? What is the healing potential of distal tibial bone loss treated with a staged method using antibiotic beads and subsequent autogenous cancellous grafting compared to other locations of the tibia? The following risk factors for delayed healing after external fixation were identified: post-reduction fracture gap of >3 mm and fixation of the associated fibula fracture. Fracture displacement could be better controlled with initial temporary external fixation than with early definitive fixation, but it had no significant effect on healing time, functional outcome or complication rate. Osteoinduction with rhBMP-7 was found to accelerate fracture healing and to shorten the sick leave. A staged method using antibiotic beads and subsequent autogenous cancellous grafting proved to be effective in the treatment of tibial bone loss. Healing potential of the bone loss in distal tibia was at least equally good as in other locations of the tibia.

Factors Associated With Early Functional Outcome After Hip Fracture Surgery

PubMed Central

Cong, Guang-Ting; Nwachukwu, Benedict U.; Patt, Minda L.; Desai, Pingal; Zambrana, Lester; Lane, Joseph M.

2016-01-01

Background: Hip fractures are common in the elderly and are likely to become more prevalent as the US population ages. Early functional status is an indicator of longer term outcome, yet in-hospital predictors of functional recovery, particularly time of surgery and composition of support staff, after hip fracture surgery have not been well studied. Methods: Ninety-nine consecutive patients underwent hip fracture surgery by a single surgeon between 2009 and 2013. Surgery after 48 hours was deemed as surgical delay, and surgery after 5 pm was deemed as after hours. Surgical support staff experience was determined by experts from our institution as well as documented level of training. Functional status was determined by independent ambulation on postoperative day (POD) 3. Results: On POD3, 48 (79%) of 62 patients with no delay were able to ambulate, whereas only 14 (38%) of 37 patients with delayed surgery were able to ambulate (P < .001). This relationship persisted when adjusted for American Society of Anesthesiologist classification. No delay in patients older than 80 (odds ratio [OR], 6.91; 95% confidence interval [CI], 2.16-22.10) and females (OR, 7.05; 95% CI, 2.34-21.20) was associated with greater chance of early ambulation. After-hours surgery was not associated with ambulation (P = .35). Anesthesiologist and circulating nurse experience had no impact on patient’s ambulatory status; however, nonorthopedic scrub technicians were associated with worse functional status (OR 7.50; 95% CI, 1.46-38.44, P = .01). Conclusion: Surgical delay and nonorthopedic scrub technicians are associated with worse early functional outcome after hip fracture surgery. Surgical delay should be avoided in older patients and women. More work should be done to understand the impact of surgical team composition on outcome. PMID:26929850

Feasibility of using administrative data for identifying medical reasons to delay hip fracture surgery: a Canadian database study.

PubMed

Guy, Pierre; Sheehan, Katie J; Morin, Suzanne N; Waddell, James; Dunbar, Michael; Harvey, Edward; Sirett, Susan; Sobolev, Boris; Kuramoto, Lisa; Tang, Michael

2017-10-05

Failure to account for medically necessary delays may lead to an underestimation of early surgery benefits. This study investigated the feasibility of using administrative data to identify the National Institute for Health and Care Excellence (NICE) 124 guideline list of conditions that appropriately delay hip fracture surgery. We assembled a list of diagnosis and procedure codes to reflect the NICE 124 conditions. The list was reviewed and updated by an advanced clinical coder. The list was refined by five clinical experts. We then screened Canadian Institute for Health Information discharge abstracts for 153 918 patients surgically treated for a non-pathological first hip fracture between 1 January 2004 and 31 December 2012 for diagnosis codes present on admission and procedure codes that antedated hip fracture surgery. We classified abstracts as having medical reasons for delaying surgery based on the presence of these codes. In total, 10 237 (6.7%; 95% CI 6.5% to 6.8%) patients had diagnostic and procedure codes indicating medical reasons for delay. The most common reasons for medical delay were exacerbation of a chronic chest condition (35.9%) and acute chest infection (23.2%). The proportion of patients with reasons for medical delays increased with time from admission to surgery: 3.9% (95% CI 3.6% to 4.1%) for same day surgery; 4.7% (95% CI 4.5% to 4.8%) for surgery 1 day after admission; 7.1% (95% CI 6.9% to 7.4%) for surgery 2 days after admission; and 15.5% (95% CI 15.1% to 16.0%) for surgery more than 2 days after admission. The trend was seen for admissions on weekday working hours, weekday after hours and on weekends. Administrative data can be considered to identify conditions that appropriately delay hip fracture surgery. Accounting for medically necessary delays can improve estimates of the effectiveness of early surgery. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Correlation between RUST assessments of fracture healing to structural and biomechanical properties.

PubMed

Cooke, Margaret E; Hussein, Amira I; Lybrand, Kyle E; Wulff, Alexander; Simmons, Erin; Choi, Jeffrey H; Litrenta, Jody; Ricci, William M; Nascone, Jason W; O'Toole, Robert V; Morgan, Elise F; Gerstenfeld, Louis C; Tornetta, Paul

2018-03-01

Radiographic Union Score for Tibia (RUST) and modified RUST (mRUST) are radiographic tools for quantitatively evaluating fracture healing using a cortical scoring system. This tool has high intra-class correlation coefficients (ICCs); however, little evidence has evaluated the scores against the physical properties of bone healing. Closed, stabilized fractures were made in the femora of C3H/HeJ male mice (8-12 week-old) of two dietary groups: A control and a phosphate restricted diet group. Micro-computed tomography (µCT) and torsion testing were carried out at post-operative days (POD) 14, 21, 35, and 42 (n = 10-16) per group time-point. Anteroposterior and lateral radiographic views were constructed from the µCT scans and scored by five raters. The raters also indicated if the fracture were healed. ICCs were 0.71 (mRUST) and 0.63 (RUST). Both RUST scores were positively correlated with callus bone mineral density (BMD) (r = 0.85 and 0.80, p < 0.001) and bone volume fraction (BV/TV) (r = 0.86 and 0.80, p < 0.001). Both RUST scores positively correlated with callus strength (r = 0.35 and 0.26, p < 0.012) and rigidity (r = 0.50 and 0.39, p < 0.001). Radiographically healed calluses had a mRUST ≥13 and a RUST ≥10 and had excellent relationship to structural and biomechanical metrics. Effect of delayed healing due to phosphate dietary restrictions was found at later time points with all mechanical properties (p < 0.011), however no differences found in the RUST scores (p > 0.318). Clinical relevance of this study is both RUST scores showed high correlation to physical properties of healing and generally distinguished healed vs. non-healed fractures. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:945-953, 2018. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Individual risk factors for deep infection and compromised fracture healing after intramedullary nailing of tibial shaft fractures: a single centre experience of 480 patients.

PubMed

Metsemakers, W-J; Handojo, K; Reynders, P; Sermon, A; Vanderschot, P; Nijs, S

2015-04-01

Despite modern advances in the treatment of tibial shaft fractures, complications including nonunion, malunion, and infection remain relatively frequent. A better understanding of these injuries and its complications could lead to prevention rather than treatment strategies. A retrospective study was performed to identify risk factors for deep infection and compromised fracture healing after intramedullary nailing (IMN) of tibial shaft fractures. Between January 2000 and January 2012, 480 consecutive patients with 486 tibial shaft fractures were enrolled in the study. Statistical analysis was performed to determine predictors of deep infection and compromised fracture healing. Compromised fracture healing was subdivided in delayed union and nonunion. The following independent variables were selected for analysis: age, sex, smoking, obesity, diabetes, American Society of Anaesthesiologists (ASA) classification, polytrauma, fracture type, open fractures, Gustilo type, primary external fixation (EF), time to nailing (TTN) and reaming. As primary statistical evaluation we performed a univariate analysis, followed by a multiple logistic regression model. Univariate regression analysis revealed similar risk factors for delayed union and nonunion, including fracture type, open fractures and Gustilo type. Factors affecting the occurrence of deep infection in this model were primary EF, a prolonged TTN, open fractures and Gustilo type. Multiple logistic regression analysis revealed polytrauma as the single risk factor for nonunion. With respect to delayed union, no risk factors could be identified. In the same statistical model, deep infection was correlated with primary EF. The purpose of this study was to evaluate risk factors of poor outcome after IMN of tibial shaft fractures. The univariate regression analysis showed that the nature of complications after tibial shaft nailing could be multifactorial. This was not confirmed in a multiple logistic regression model, which only revealed polytrauma and primary EF as risk factors for nonunion and deep infection, respectively. Future strategies should focus on prevention in high-risk populations such as polytrauma patients treated with EF. Copyright © 2014 Elsevier Ltd. All rights reserved.

The influence of procedure delay on resource use: a national study of patients with open tibial fracture.

PubMed

Sears, Erika Davis; Burke, James F; Davis, Matthew M; Chung, Kevin C

2013-03-01

The purpose of this study was to (1) understand national variation in delay of emergency procedures in patients with open tibial fracture at the hospital level and (2) compare length of stay and cost in patients cared for at the best- and worst-performing hospitals for delay. The authors retrospectively analyzed the 2003 to 2009 Nationwide Inpatient Sample. Adult patients with open tibial fracture were included. Hospital probability of delay in performing emergency procedures beyond the day of admission was calculated. Multilevel linear regression random-effects models were created to evaluate the relationship between the treating hospital's tendency for delay (in quartiles) and the log-transformed outcomes of length of stay and cost. The final sample included 7029 patients from 332 hospitals. Patients treated at hospitals in the fourth (worst) quartile for delay were estimated to have 12 percent (95 percent CI, 2 to 21 percent) higher cost compared with patients treated at hospitals in the first quartile. In addition, patients treated at hospitals in the fourth quartile had an estimated 11 percent (95 percent CI, 4 to 17 percent) longer length of stay compared with patients treated at hospitals in the first quartile. Patients with open tibial fracture treated at hospitals with more timely initiation of surgical care had lower cost and shorter length of stay than patients treated at hospitals with less timely initiation of care. Policies directed toward mitigating variation in care may reduce unnecessary waste.

Lack of endogenous parathyroid hormone delays fracture healing by inhibiting vascular endothelial growth factor‑mediated angiogenesis.

PubMed

Ding, Qingfeng; Sun, Peng; Zhou, Hao; Wan, Bowen; Yin, Jian; Huang, Yao; Li, Qingqing; Yin, Guoyong; Fan, Jin

2018-07-01

Intermittent low‑dose injections of parathyroid hormone (PTH) have been reported to exert bone anabolic effects and to promote fracture healing. As an important proangiogenic cytokine, vascular endothelial growth factor (VEGF) is secreted by bone marrow mesenchymal stem cells (BMSCs) and osteoblasts, and serves a crucial regulatory role in the process of vascular development and regeneration. To investigate whether lack of endogenous PTH causes reduced angiogenic capacity and thereby delays the process of fracture healing by downregulating the VEGF signaling pathway, a PTH knockout (PTHKO) mouse fracture model was generated. Fracture healing was observed using X‑ray and micro‑computerized tomography. Bone anabolic and angiogenic markers were analyzed by immunohistochemistry and western blot analysis. The expression levels of VEGF and associated signaling pathways in murine BMSC‑derived osteoblasts were measured by quantitative polymerase chain reaction and western blot analysis. The expression levels of protein kinase A (PKA), phosphorylated‑serine/threonine protein kinase (pAKT), hypoxia‑inducible factor‑1α (HIF1α) and VEGF were significantly decreased in BMSC‑derived osteoblasts from PTHKO mice. In addition, positive platelet endothelial cell adhesion molecule staining was reduced in PTHKO mice, as determined by immunohistochemistry. The expression levels of HIF1α, VEGF, runt‑related transcription factor 2, osteocalcin and alkaline phosphatase were also decreased in PTHKO mice, and fracture healing was delayed. In conclusion, lack of endogenous PTH may reduce VEGF expression in BMSC‑derived osteoblasts by downregulating the activity of the PKA/pAKT/HIF1α/VEGF pathway, thus affecting endochondral bone formation by causing a reduction in angiogenesis and osteogenesis, ultimately leading to delayed fracture healing.

Complex tibial fracture outcomes following treatment with low-intensity pulsed ultrasound.

PubMed

Leung, Kwok-Sui; Lee, Wing-Sze; Tsui, Hon-For; Liu, Paul Po-Lung; Cheung, Wing-Hoi

2004-03-01

A clinical study was conducted to investigate the effect of low-intensity pulsed ultrasound (US) stimulation (LIPUS) on the healing of complex tibial fractures. Thirty complex tibial fractures were randomly assigned to the treatment with LIPUS (n = 16) or by a dummy machine (sham-exposed: n = 14). The fractures were immobilized by either internal or external fixations according to the clinical indications. LIPUS was given 20 min/day for 90 days. Fracture healing was monitored by clinical, radiological, densitometric and biochemical assessments. The LIPUS-treated group showed statistically significantly better healing, as demonstrated by all assessments. Complications were minimal in the LIPUS group. There were two cases of delayed union, with one in each group. There were two cases of infection in the control group. The delayed-union cases were subsequently treated by LIPUS and the infection cases were treated with standard protocol. Fracture healing in these patients was again treated by LIPUS.

The corrosion fatigue fractography of Ti-24Al-11Nb

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Y.; Wang, Y.B.; Chu, W.Y.

1994-03-01

Many researchers have studied the fracture behaviors and fractography of the Ti-24Al-11Nb alloy. While hydrogen induced delayed fracture could occur in this titanium aluminide in hydrogen gas at temperatures above 300[degree]C, there was no obvious difference in fractography of the alloy in hydrogen or air. The fractography of stress corrosion cracking in a solution was also similar to that of overloaded fracture in air. The recent work showed that hydrogen induced delayed fracture for a notched sample could occur during dynamic cathodic charging at the temperature. There were a lot of small dimples on the fracture surface near the notchmore » tip when K[sub I] neared the threshold k[sub IH]. This differed from that of an overloaded fracture. The fractography of corrosion fatigue in methanol or during dynamic charging for the Ti-24Al-11Nb alloy was studied in this paper.« less

Delayed presentation is no barrier to satisfactory outcome in the management of open tibial fractures.

PubMed

Ashford, Robert U; Mehta, Janak A; Cripps, Robin

2004-04-01

The management of open tibial fractures is a challenge to all orthopaedic trauma surgeons. The major goals are fracture union, uncomplicated soft tissue healing and return to pre-injury level of function. The geographical isolation and vastness of the Northern Territory of Australia complicates the management of these injuries by adding a significant delay to treatment. Forty-five patients sustained 48 open tibial fractures over the 30-month period of the study. Twelve received primary surgical treatment within 6h of injury but 33 were treated more than 6h after injury. The mean time to treatment in this latter group was 12h 15min (median 9h 45min, range 6-37h). The majority of injuries were high energy, with 23 patients having multiple injuries and 29 fractures (60%) being classified as AO C3 with 35 (73%) having Gustilo III soft tissue injuries. There was a mean time to union of 7.5 months and an overall complication rate of 42.2%. Thirteen patients (29%) required additional (late) surgical procedures subsequent to definitive fracture and soft tissue management. The zone of injury infection rate was 12.5%. The high incidence of open tibial fractures places a large financial burden on the state. However, despite the absence of a plastic surgical service and delays in presentation, satisfactory outcomes can be obtained by the application of the established surgical principles of thorough debridement, soft tissue management and fracture stabilisation.

Titanium Mesh Reconstruction of Orbital Roof Fracture with Traumatic Encephalocele: A Case Report and Review of Literature

PubMed Central

Mokal, Nitin J.; Desai, Mahinoor F.

2012-01-01

Orbital roof fractures are rare. Traumatic encephaloceles in the orbital cavity are even rarer, with only 21 cases published to date. Orbital roof fractures are generally encountered in males between 20 and 40 years of age following automobile collision. We report a case of an orbital roof fracture with traumatic encephalocele into the left orbit. Early diagnosis and treatment are very important because the raised intraorbital pressure may irreversibly damage the optic nerve. Computed tomography with 3-D reconstruction, the imaging modality of choice, showed the displaced fracture fragment deep into the orbit. Reconstruction of the orbital roof should be performed in every case. We used an extracranial approach to elevate the fracture with titanium mesh to stabilize the fragment. The cosmetic results were excellent but delay in treatment was responsible for delayed recovery of vision. The case report is followed by a brief overview of orbital roof fractures including pertinent review of literature. PMID:23450105

Delayed presentation of a loose body in undisplaced paediatric talar neck fracture

PubMed Central

Patel, Vishal; Bloch, Benjamin; Johnson, Nicholas; Mangwani, Jitendra

2014-01-01

Fractures of the talus are rare in children. A high index of suspicion is needed to avoid missing such an injury, which is not an uncommon occurrence especially with undisplaced fractures. We present an unusual case of an undisplaced talar neck fracture in a five-year-old child leading to a delayed presentation of a symptomatic osteochondral loose body in the ankle joint. To our knowledge there are no reports in the literature of osteochondral loose bodies occurring in conjunction with an associated undisplaced talar neck fracture in either children or adults. The loose body was removed using anterior ankle arthroscopy. The child had an uneventful post operative recovery and regained full range of movement and function of his ankle joint and was discharged at one year follow-up. We aim to highlight the need to have a low threshold to further evaluate symptomatic children after fracture healing of an undisplaced talar neck fracture for a possible associated loose body in the ankle joint. PMID:25035846

Management of neglected open extremity fractures in low-resource settings: Experience of the French Army Medical Service in Chad.

PubMed

Mathieu, L; Mottier, F; Bertani, A; Danis, J; Rongiéras, F; Chauvin, F

2014-11-01

The purpose of this study was to report the experience of the French Army Medical Service in the management of neglected open extremity fractures and related-complications in Chad. Delayed treatment of open extremity fractures is possible in a low-resource setting. An observational prospective study was performed in a French Forward Surgical Team deployed in N'Djamena for six months. Twenty-seven patients, 24 men and three women, mean age 30 years old with an open fracture that was managed more than 24 hours after it occurred were included. The mean treatment delay was 83 days. Fractures were located in the tibia in 20 cases. There were 15 non-infected and twelve infected fractures. The number of cases of debridement, flap coverage, and the overall number of procedures were higher in the group with infection, but the difference was not significant. Treatment of infected fractures was complicated by six early recurrent infections, while there were no complications in the group without infection. The mean follow-up was 4.4 months. Infection was controlled in eleven cases, however evaluation of fracture healing was limited because of the short follow-up in the group with infection. Functional outcome of the lower extremities was often complicated by knee stiffness. Delayed management of open fractures depends on the available resources. In low-resource settings, the goals of surgery should be modest. Treatment of non-infected injuries and osteomyelitis is possible. On the other hand, treatment of infected fractures and septic nonunions should be undertaken with caution if all the necessary aspects of treatment, in particular extended antibiotic treatment and sequential procedures are not possible. level IV. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Biomechanical properties of a structurally optimized carbon-fibre/epoxy intramedullary nail for femoral shaft fracture fixation.

PubMed

Samiezadeh, Saeid; Fawaz, Zouheir; Bougherara, Habiba

2016-03-01

Intramedullary nails are the golden treatment option for diaphyseal fractures. However, their high stiffness can shield the surrounding bone from the natural physiologic load resulting in subsequent bone loss. Their stiff structure can also delay union by reducing compressive loads at the fracture site, thereby inhibiting secondary bone healing. Composite intramedullary nails have recently been introduced to address these drawbacks. The purpose of this study is to evaluate the mechanical properties of a previously developed composite IM nail made of carbon-fibre/epoxy whose structure was optimized based on fracture healing requirements using the selective stress shielding approach. Following manufacturing, the cross-section of the composite nail was examined under an optical microscope to find the porosity of the structure. Mechanical properties of the proposed composite intramedullary nail were determined using standard tension, compression, bending, and torsion tests. The failed specimens were then examined to obtain the modes of failure. The material showed high strength in tension (403.9±7.8MPa), compression (316.9±10.9MPa), bending (405.3±8.1MPa), and torsion (328.5±7.3MPa). Comparing the flexural modulus (41.1±0.9GPa) with the compressive modulus (10.0±0.2GPa) yielded that the material was significantly more flexible in compression than in bending. This customized flexibility along with the high torsional stiffness of the nail (70.7±2.0Nm(2)) has made it ideal as a fracture fixation device since this unique structure can stabilize the fracture while allowing for compression of fracture ends. Negligible moisture absorption (~0.5%) and low porosity of the laminate structure (< 3%) are other advantages of the proposed structure. The findings suggested that the carbon-fibre/epoxy intramedullary nail is flexible axially while being relatively rigid in bending and torsion and is strong enough in all types of physiologic loading, making it a potential candidate for use as an alternative to the conventional titanium-alloy intramedullary nails. Copyright © 2015 Elsevier Ltd. All rights reserved.

Posterior urethral stricture repair following trauma and pelvic fracture.

PubMed

Rios, Emilio; Martinez-Piñeiro, Luis; Álvarez-Maestro, Mario

2014-01-01

Posterior urethral injuries typically arise in the context of a pelvic fracture.The correct and appropriate initial treatment of associated urethral rupture is critical to the proper healing of the injury. In this paper, we provide a comprehensive review of the literature with special emphasis on the various treatments available: open or endoscopic primary realignment, immediate or delayed urethroplasty after suprapubic cystostomy, and delayed optical urethrotomy.

The Effects of Injury Magnitude on the Kinetics of the Acute Phase Response

PubMed Central

Bauzá, Graciela; Miller, Glenn; Kaseje, Neema; Wigner, Nathan A.; Wang, Zhongyan; Gerstenfeld, Louis C.; Burke, Peter A.

2013-01-01

Background The acute-phase response (APR) is critical to the body's ability to successfully respond to injury. A murine model of closed unilateral femur fractures and bilateral femur fracture were used to study the effect of injury magnitude on this response. Methods Standardized unilateral femur fracture and bilateral femur fracture in mice were performed. The femur fracture sites, livers, and serum were harvested over time after injury. Changes in mRNA expression of cytokines, hepatic acute-phase proteins, and serum cytokines overtime were measured. Results There was a rapid and short-lived hepatic APR to fracture injuries. The overall pattern in both models was similar. Both acute-phase proteins' mRNA (fibrinogen-γ and serum amyloid A-3) showed increased mRNA expression over baseline within the first 48 hours and their levels positively correlated with the extent of injury. However, increased severity of injury resulted in a delayed induction of the APR. A similar effect on the gene expression of cytokines (interleukin [IL]-1β, IL-6, and tumor necrosis factor-α) at the fracture site was seen. Serum IL-6 levels increased with increased injury and showed no delay between injury models. Conclusions Greater severity of injury resulted in a delayed induction of the liver's APR and a diminished expression of cytokines at the fracture site. Serum IL-6 levels were calibrated to the extent of the injury, and changes may represent mechanisms by which the local organ responses to injury are regulated by the injury magnitude. PMID:20693926

Reverse distal femoral locking compression plate a salvage option in nonunion of proximal femoral fractures.

PubMed

Dumbre Patil, Sampat S; Karkamkar, Sachin S; Patil, Vaishali S Dumbre; Patil, Shailesh S; Ranaware, Abhijeet S

2016-01-01

When primary fixation of proximal femoral fractures with implants fails, revision osteosynthesis may be challenging. Tracts of previous implants and remaining insufficient bone stock in the proximal femur pose unique problems for the treatment. Intramedullary implants like proximal femoral nail (PFN) or surface implants like Dynamic Condylar Screw (DCS) are few of the described implants for revision surgery. There is no evidence in the literature to choose one implant over the other. We used the reverse distal femur locking compression plate (LCP) of the contralateral side in such cases undergoing revision surgery. This implant has multiple options of fixation in proximal femur and its curvature along the length matches the anterior bow of the femur. We aimed to evaluate the efficacy of this implant in salvage situations. Twenty patients of failed primary proximal femoral fractures who underwent revision surgery with reverse distal femoral locking plate from February 2009 to November 2012 were included in this retrospective study. There were 18 subtrochanteric fractures and two ipsilateral femoral neck and shaft fractures, which exhibited delayed union or nonunion. The study included 14 males and six females. The mean patient age was 43.6 years (range 22-65 years) and mean followup period was 52.1 months (range 27-72 months). Delayed union was considered when clinical and radiological signs of union failed to progress at the end of four months from initial surgery. All fractures exhibited union without any complications. Union was assessed clinically and radiologically. One case of ipsilateral femoral neck and shaft fracture required bone grafting at the second stage for delayed union of the femoral shaft fracture. Reverse distal femoral LCP of the contralateral side can be used as a salvage option for failed fixation of proximal femoral fractures exhibiting nonunion.

Penile fracture: surgical repair and late effects on erectile function.

PubMed

Ateyah, Ahmed; Mostafa, Taymour; Nasser, Taha Abdel; Shaeer, Osama; Hadi, Ahmed Abdel; Al-Gabbar, Mohammed Abd

2008-06-01

Penile fracture is described as a traumatic rupture of the tunica albuginea because of blunt injury of an erect penis. To assess the etiology, treatment maneuvers, and late effects of penile fractures treated by surgical repair. Thirty-three patients diagnosed provisionally as having fractured penises. Thirty patients were managed by immediate surgical repair and three by delayed repair. International Index of Erectile Function-5 for married cases and Single-question Self-report of Erectile Dysfunction questionnaires and recording complications after 2, 3, and 6 months. The most common cause of fracture penis is self-inflicted acute bending (54.5%). The tear was visualized by ultrasound in 20/30 patients (66.7%) mostly on the right proximal third of the penis. All tears were unilateral with mean length 2.0 +/- 0.9 cm (range 0.5-4 cm). All patients who completed their follow-up after 6 months (N = 24) were able to achieve an adequate erection except two married cases who felt mild erectile dysfunction. Penile nodules were the most common postoperative complication (41.7%) after 6 months' follow-up. Patients treated with immediate or delayed repair had comparable complications. Fracture penis is not uncommon as an emergency that must be repaired either immediately or delayed. Clinical diagnosis is more predictive than ultrasound in diagnosis and determining the site of the tear. Ultrasound may be of value in patients where there is clinical doubt.

Vertebral Compression Fractures

MedlinePlus

... and monitored to avoid putting pressure on the ribs that can cause new fractures. Surgical Procedures • When there is severe incapacitating pain • When healing is delayed or when bone fragments ...

Anatomical frame plate osteosynthesis in Ada-Miller Type 2 or 4 scapula fractures.

PubMed

Esenkaya, İrfan; Ünay, Koray

2011-01-01

The aim of this prospective study was to evaluate the results of anatomical frame plate osteosynthesis in patients with Ada and Miller Type 2 or 4 scapula fractures. Eleven Ada and Miller Type 2 or 4 scapula fractures in nine patients were treated with anatomical frame plate osteosynthesis. The mean follow-up time was 39.8 (12-77) months. The results were evaluated using the Herscovici score. No complications, such as neurovascular injury, postoperative hematoma, infection, delayed wound healing, implant failure, delayed union, or nonunion occurred. Based on the Herscovici score, the results were excellent. Osteosynthesis with anatomical frame plates appears to be a safe method that allows early range of motion and that provides excellent results in Ada and Miller Type 2 or 4 scapula fractures.

Application of Local Vibrations in Delayed and Non-Union Fractures: a Case Study

NASA Astrophysics Data System (ADS)

Trombetta, Chiara; Abundo, Paolo; Foti, Calogero; Rosato, Nicola

2011-02-01

The aim of the study was to assess the efficacy of local vibration treatments (LV) in delayed-union and non-union fractures, through therapeutic exercise vibration (TEV) practice, analysing the radiological trend. The Medical Engineering Service of the Fondazione Policlinico Tor Vergata in collaboration with the Chair-Department of Rehabilitation Medicine of the University of Rome Tor Vergata and the Boscosystem company, is developing a device dedicated to LV application, to favour bone regeneration and muscle strengthening. This case report analyses the bone activity of a male patient presenting a right tibial fracture, treated with TEV. At the end of the TEV program, clinical results confirmed independent ambulation with disappearance of perimalleolar edema, while radiographic images revealed the presence of bone repair activity around the fracture line.

The Influence of Procedure Delay on Resource Utilization: A National Study of Patients with Open Tibial Fracture

PubMed Central

Sears, Erika Davis; Burke, James F.; Davis, Matthew M.; Chung, Kevin C.

2016-01-01

Background The purpose of this study is to 1) understand national variation in delay of emergency procedures in patients with open tibial fracture at the hospital level and 2) compare length of stay (LOS) and cost in patients cared for at the best and worst performing hospitals for delay. Methods We retrospectively analyzed the 2003 – 2009 Nationwide Inpatient Sample. Adult patients with primary diagnosis of open tibial fracture were selected for inclusion. We calculated hospital probability of delay of emergency procedures beyond the day of admission (day 0). Multilevel linear regression random effects models were created to evaluate the relationship between the treating hospital’s tendency for delay (in quartiles) and the log-transformed outcomes of LOS and cost, while adjusting for patient and hospital variables. Results The final sample included 7,029 patients from 332 hospitals. Adjusted analyses demonstrate that patients treated at hospitals in the fourth (worst) quartile for delay were estimated to have 12% (95% CI 2–21%) higher cost compared to patients treated at hospitals in the first quartile. In addition, patients treated at hospitals in the fourth quartile had an estimated 11% (CI 4–17%) longer LOS compared to patients treated at hospitals in the first quartile. Conclusions Patients with open tibial fracture treated at hospitals with more timely initiation of surgical care had lower cost and shorter LOS than patients treated at hospitals with less timely initiation of care. Policies directed toward mitigating variation in care are not only beneficial for patient outcomes, but may also reduce unnecessary waste. Level II (Prognostic) PMID:23142940

The long-term outcome of displaced mid-third clavicle fractures on scapular and shoulder function: variations between immediate surgery, delayed surgery, and nonsurgical management.

PubMed

George, Daniel M; McKay, Bartholomew P; Jaarsma, Ruurd L

2015-05-01

Conservative management for uncomplicated displaced clavicle fractures is common practice. Delay of surgical fixation may result in less favorable outcomes. A retrospective cohort study was conducted of 60 patients with a closed mid-third clavicle fracture that did not meet current operative or nonoperative guidelines; 20 primary (plate fixation <6 weeks), 20 delayed (plate fixation >6 weeks), and 20 matched conservative patients were included. Each patient completed 2 questionnaires, the Disabilities of the Arm, Shoulder, and Hand and the American Shoulder and Elbow Surgeons, as well as visual analog scales for pain, cosmetic satisfaction, and overall satisfaction. In addition, 10 patients from each group underwent clinical review of scapular rotation by the lateral scapular slide test, clinical impingement, range of motion assessment, and radiologic review of clavicle union and length. The American Shoulder and Elbow Surgeons patient self-reported questionnaire demonstrated a median score of 5.5 for the delayed group, 2 for the primary group, and 1 for the conservative group (P = .032). The median Disabilities of the Arm, Shoulder, and Hand score was 7.92 for the delayed group, 3.32 for the primary group, and 1.67 for the conservative group (P = .212). Six patients in the delayed group had scapular malrotation compared with 2 in the primary group and none in the conservative group (P = .008). Flexion and external rotation in 90° abduction were decreased in the conservative group (P = .049 and .041, respectively). We support the conservative management of uncomplicated displaced clavicle fractures but recognize that a lower threshold for early surgery should be considered where optimal shoulder function is required. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Management of genitourinary injuries in patients with pelvic fractures.

PubMed Central

Weems, W L

1979-01-01

Associated injuries frequently occur in patients who sustain fractures of the pelvis. Hemorrhage from intrapelvic vessels, rupture of the urinary bladder and avulsion of the membranous urethra in males are among the integral risks in this trauma. Non-operative methods of managing hemorrhage have gained favor in recent experience. The case records of 282 male patients with pelvic fractures were reviewed to evaluate experience with lower genitourinary injuries. Early recognition is important in bladder injuries, and surgical repair is advised, except in selected patients who may be managed by catheter drainage alone. Delayed complications of bladder injury are rare. Membranous urethral injuries entail a high risk of chronic stricture disease and sexual impotence. The rationale of early repair versus delayed repair of these injuries is discussed. The results in this series show advantage for delayed repair. Images Fig. 2. Fig. 3. PMID:453943

Surgical treatment of open pilon fractures.

PubMed

Zeng, Xian-tie; Pang, Gui-gen; Ma, Bao-tong; Mei, Xiao-long; Sun, Xiang; Wang, Jia; Jia, Peng

2011-02-01

To discuss the methods, timing and clinical outcomes of surgical treatment for open pilon fractures. From April 2003 to July 2008, 28 patients with open pilon fractures were treated. All had type C fractures according to the Arbeitsgemeinschaft für osteosynthesefragen-Association for the Study of Internal Fixation (AO/ASIF) classification. Three operative methods were applied, the methods being determined by the types of fracture, soft tissue damage and time interval after injury. Seven cases were treated by debridement and internal fixation with plate; 19 by limited internal fixation combined with external fixation; and 2 by delayed surgery. The clinical outcomes were evaluated by the Burwell-Charnley score. All cases were followed up for from 6 to 48 months (average 24 months). The Burwell-Charnley score of clinical outcomes: anatomic reduction achieved in 12 cases, functional reduction in 15, and unsatisfactory reduction in 1. The healing time was from 2.5 to 11 months (average 4.7 months). Two cases had delayed union. According to the American Orthopaedic Foot and Ankle Society (AOFAS) scale for the ankle joint, there were excellent results in 8 cases, good in 14, fair in 5 and poor in 1. Complications included four cases of skin superficial sloughing, two of superficial infection, one of deep infection, two of delayed fracture union and ten of post-traumatic arthritis. It is important to perform appropriate surgeries for open pilon fracture according to fracture classification, different damage to skin and tissue and time interval after injury. Thorough debridement, proper use of anti-infective medication, appropriate bone grafting, and postoperative ankle function exercise can reduce the occurrence of complications. © 2011 Tianjin Hospital and Blackwell Publishing Asia Pty Ltd.

Dependence for basic and instrumental activities of daily living after hip fractures.

PubMed

González-Zabaleta, Jorge; Pita-Fernandez, Salvador; Seoane-Pillado, Teresa; López-Calviño, Beatriz; Gonzalez-Zabaleta, Jose Luis

2015-01-01

The objective of the study is to determine basic activities of daily living (Barthel Index) and instrumental activities of daily living (Lawton-Brody Index) before and after hip fracture. Follow-up study of patients (n=100) with hip fracture, operated at Complejo Hospitalario Universitario de A Coruña (Spain). Period January/2009-December/2011. Demographic characteristic of the patients, Charlson Index, Glomerular filtration rate, Barthel index, Lawton index, type of proximal femur fracture and surgical treatment delay were recorded. Multivariate regression was performed. Informed patient consent and ethical review approval were obtained. Before fracture were independent for activities of daily living (ADL) a 38.0%, at 90 days were 15.4%. The Barthel index score decreased from 75.2±28.2 to 56.5±31.8) (p<0.0001). If we consider the age, gender, comorbidity (Charlson index), renal function, fracture type and surgical delay objectify the only independent variable to predict dependency effect is age. If we also consider the Barthel score objectify the variable that significantly modifies that score at 90 days is the baseline value of the index. The prevalence of independence for instrumental activities of daily living (IADL) at the baseline moment is 11% and at 90 days is decreased to 2.2%. There is a decrease in the independence effect in all activities. The variable predictor of independence for all activities after taking into consideration age, sex, comorbidity, fracture type, surgical delay and renal function is the baseline score of the Barthel and Lawton index. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Functional Impact of a Minor Thoracic Injury: An Investigation of Age, Delayed Hemothorax, and Rib Fracture Effects.

PubMed

Émond, Marcel; Sirois, Marie-Josée; Guimont, Chantal; Chauny, Jean-Marc; Daoust, Raoul; Bergeron, Éric; Vanier, Laurent; Camden, Stephanie; Le Sage, Natalie

2015-12-01

To investigate whether minor thoracic injuries (MTIs) relate to subsequent functional limitations. Approximately 75% of patients with an MTI are discharged after an emergency department (ED) visit, whereas significant functional limitations can occur in the weeks that follow. A 19 months' prospective cohort study with a 90-day follow-up was conducted at 4 university-affiliated EDs. Patients 16 years and older with an MTI were assessed at initial ED visit, 7, 14, 30, and 90 days after injury. Functional outcome was measured using the SF-12 scale. General linear model were used to assess outcome. A total of 482 patients were included, of whom 127 (26.3%) were 65 or older. Overall, 147 patients (30.5%) presented with at least 1 rib fracture and 59 subjects (12.2%) with delayed hemothorax. At 90 days, 22.8% of patients still had severe or moderate disabilities on global physical health score. Patients with solely delayed hemothorax and no rib fracture had the lowest global physical health score (46.4 vs 61.1, P < 0.01, effect size =  -2.60) than patients with simple MTI. Generally, functional limitations also increase with increments of number of rib fracture detected on radiograph. Outcomes were not different among patients 65 years or older when compared to their younger counterparts. In this prospective study of MTIs, severe to moderate disabilities were present in nearly 1 patient out of 5 at 90 days. The presence of delayed hemothorax and the number of rib fracture were associated with increased functional limitations after a MTI.

Female urethral injuries associated with pelvic fracture: a systematic review of the literature.

PubMed

Patel, Devin N; Fok, Cynthia S; Webster, George D; Anger, Jennifer T

2017-12-01

To review systematically the literature on female urethral injuries associated with pelvic fracture and to determine the optimum management of this rare injury. Using Meta-analysis of Observational Studies in Epidemiology criteria, we searched the Cochrane, Pubmed and OVID databases for all articles available before 30 June 2016 using the terms 'female pelvic fracture urethroplasty', 'female urethral distraction', 'female pelvic fracture urethral injury' and 'female pelvic fracture urethra girls.' Two authors of this paper independently reviewed the titles, abstracts, and articles in duplicate. We identified 162 individual articles from the databases. Fifty-one articles met our criteria for full review, including 158 female patients with urethral trauma. Of these injuries, 83 (53%) were managed with immediate repair; 17/83 (20%) via primary alignment and 66/83 (80%) via anastomotic repair. The remaining 75/158 (47%) were managed with delayed repair. Rates of urethral stenosis and fistula were highest after primary alignment. Urethral integrity appears to be similar after both primary anastomosis and delayed repair; however, patients experienced significantly more incontinence and vaginal stenosis after delayed repair. Patients who underwent delayed urethral repair were more likely to undergo more extensive reconstructive surgery than those who underwent primary repair. The optimum management of female urethral distraction defects is based on very-low-quality literature. Based on our review of the available literature, primary anastomotic repair of a female urethral distraction defect via a vaginal approach as soon as the patient is haemodynamically stable appears to be optimal. © 2017 The Authors BJU International © 2017 BJU International Published by John Wiley & Sons Ltd.

2017 Status report-Tritium aging studies on stainless steel: Effect of hydrogen, tritium and decay helium on the fracture-toughness properties of stem, cup and block forgings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morgan, Michael J.

The materials of construction of tritium reservoirs are forged stainless steels. During service, the structural properties of the stainless steel change over time because of the diffusion of tritium into the reservoir wall and its radioactive decay to helium-3. This aging effect can cause cracks to initiate and grow which could result in a tritium leak or delayed failure of a tritium reservoir. Numerous factors affect the tendency for crack formation and propagation and are being investigated in this program. The goal of the research is to provide relevant fracture mechanics data that can be used by the design agenciesmore » in their assessments of tritium reservoir structural integrity. In this status report, new experimental results are presented on the effects of tritium and decay helium on the cracking properties of specimens taken from actual tritium reservoir forgings instead of the experimental forgings of past programs. The properties measured are more representative of actual reservoir properties because the microstructure of the specimens tested are more like that of the actual tritium reservoirs. The program was designed to measure the effects of material variables on tritium compatibility and includes two stainless steels (Type 304L and 316L stainless steel), multiple yield strengths (360-500 MPa), and multiple forging shapes (Stem, Cup, and Block).« less

Fracture of the penis: an atypical presentation.

PubMed

Waseem, Muhammad; Upadhyay, Ruchi; Kapoor, Ramnath; Agyare, Samuel

2013-08-13

Fracture of the penis is an uncommon injury presenting to the emergency department (ED). Personal embarrassment and social scenarios associated with this condition may result in underreporting. Patients often delay seeking medical attention, and even when they do, as in our case report, they may withhold the condition for a significant time. ED physicians need to be aware of the social inhibitions and the need for early diagnosis and prompt treatment. A delay in treatment increases the risk of complications such as ischemia, necrosis and penile deformity.Fracture of the penis is caused by rupture of the tunica albuginea of one or both corpora cavernosa by a blunt trauma to the erect penis. Diagnosis is usually clinical as evident by the characteristic history and clinical presentation. Diagnostic modalities aid in the management of the fracture and associated injuries if present. But promptness in the recognition and initiation of treatment can significantly reduce the chances of post-injury complications. We present a case of penile fracture in a young male who presented to the ED with abdominal pain, but careful history and physical examination revealed penile fracture. A delay in diagnosis could have led to complications. Our case report is an attempt to emphasize the need to suspect injury to the penis in a young adult who might present to the emergency department with an entirely different complaint and also to treat any penile trauma as an emergency. This report provides evidence of an uncommon and underreported clinical entity. A review of the pertinent literature is included.

Nanoscale origins of the damage tolerance of the high-entropy alloy CrMnFeCoNi

DOE PAGES

Zhang, ZiJiao; Mao, M. M.; Wang, Jiangwei; ...

2015-12-09

Damage tolerance can be an elusive characteristic of structural materials requiring both high strength and ductility, properties that are often mutually exclusive. High-entropy alloys are of interest in this regard. Specifically, the single-phase CrMnFeCoNi alloy displays tensile strength levels of ~1 GPa, excellent ductility (~60–70%) and exceptional fracture toughness (KJIc>200M Pa√m). Here through the use of in situ straining in an aberration-corrected transmission electron microscope, we report on the salient atomistic to micro-scale mechanisms underlying the origin of these properties. We identify a synergy of multiple deformation mechanisms, rarely achieved in metallic alloys, which generates high strength, work hardening andmore » ductility, including the easy motion of Shockley partials, their interactions to form stacking-fault parallelepipeds, and arrest at planar slip bands of undissociated dislocations. In conclusion, we further show that crack propagation is impeded by twinned, nanoscale bridges that form between the near-tip crack faces and delay fracture by shielding the crack tip.« less

Nanoscale origins of the damage tolerance of the high-entropy alloy CrMnFeCoNi

PubMed Central

Zhang, ZiJiao; Mao, M. M.; Wang, Jiangwei; Gludovatz, Bernd; Zhang, Ze; Mao, Scott X.; George, Easo P.; Yu, Qian; Ritchie, Robert O.

2015-01-01

Damage tolerance can be an elusive characteristic of structural materials requiring both high strength and ductility, properties that are often mutually exclusive. High-entropy alloys are of interest in this regard. Specifically, the single-phase CrMnFeCoNi alloy displays tensile strength levels of ∼1 GPa, excellent ductility (∼60–70%) and exceptional fracture toughness (KJIc>200 MPa√m). Here through the use of in situ straining in an aberration-corrected transmission electron microscope, we report on the salient atomistic to micro-scale mechanisms underlying the origin of these properties. We identify a synergy of multiple deformation mechanisms, rarely achieved in metallic alloys, which generates high strength, work hardening and ductility, including the easy motion of Shockley partials, their interactions to form stacking-fault parallelepipeds, and arrest at planar slip bands of undissociated dislocations. We further show that crack propagation is impeded by twinned, nanoscale bridges that form between the near-tip crack faces and delay fracture by shielding the crack tip. PMID:26647978

Operative fixation of chest wall fractures: an underused procedure?

PubMed

Richardson, J David; Franklin, Glen A; Heffley, Susan; Seligson, David

2007-06-01

Chest wall fractures, including injuries to the ribs and sternum, usually heal spontaneously without specific treatment. However, a small subset of patients have fractures that produce overlying bone fragments that may produce severe pain, respiratory compromise, and, if untreated mechanically, result in nonunion. We performed open reduction and internal fixation on seven patients with multiple rib fractures-five in the initial hospitalization and two delayed--as well as 35 sternal fractures (19 immediate fixation and 16 delayed). Operative fixation was accomplished using titanium plates and screws in both groups of patients. All patients with rib fractures did well; there were no major complications or infections, and no plates required removal. Clinical results were excellent. There was one death in the sternal fracture group in a patient who was ventilator-dependent preoperatively and extubated himself in the early postoperative period. Otherwise, the results were excellent, with no complications occurring in this group. Three patients had their plates removed after boney union was achieved. No evidence of infection or nonunion occurred. The excellent results achieved in the subset of patients with severe chest wall deformities treated initially at our institution and those referred from outside suggest that operative fixation is a useful modality that is likely underused.

Delayed diagnosis of a peroneal artery false aneurysm at a concomitant tibial fracture. A case report.

PubMed

Tyllianakis, M; Panagiotopoulos, E; Megas, P; Lambiris, E

1995-07-01

A 49-year-old man had posttraumatic persistent calf swelling and a tibial and fibular fracture. Despite the intramedullary nailing of the fracture, the swelling did not improve, and at the 6th postoperative week it was misdiagnosed (using venogram) as deep vein thrombosis. Therefore, it was mistreated with anticoagulants, which led to great deterioration of the local signs. An arteriogram revealed an initially missed false peroneal artery aneurysm. Surgical treatment was performed immediately. The 6-week delay had led to some atrophy of the posterior compartment muscles, fortunately without any permanent disability. The importance of proper and early diagnosis of posttraumatic persistent calf swelling is stressed.

Operative stabilization of open long bone fractures: A tropical tertiary hospital experience

PubMed Central

Ifesanya, Adeleke O.; Alonge, Temitope O.

2012-01-01

Background: Operative treatment of open fractures in our environment is fraught with problems of availability of theater space, appropriate hardware, and instrumentation such that high complication rates may be expected. Materials and Methods: We evaluated all open long bone fractures operatively stabilized at our center to determine the outcome of the various treatment modalities as well as the determinant factors. Result: A total of 160 patients with 171 fractures treated between December 1995 and December 2008 were studied. There were twice as many males; mean age was 35.0 years. About half were open tibia fractures. Gustilo IIIa and IIIb fractures each accounted for 56 cases (45.2%). Fifty-three percent were stabilized within the first week of injury. Interval between injury and operative fixation averaged 11.1 days. Anderson-Hutchin's technique was employed in 27 cases (21.8%), external fixation in 21 (16.9%), plate osteosynthesis in 50 (40.3%), and intramedullary nail 15 cases (12.1%). Mean time to union was 24.7 weeks. Fifty-two complications occurred in 50 fractures (40.3%) with joint stiffness and chronic osteomyelitis each accounting for a quarter of the complications. Union was delayed in grade IIIb open fractures and those fractures treated with external fixation. Conclusion: A significant proportion of open long bone fractures we operatively treated were severe. Severe open fractures (type IIIb) with concomitant stabilization using external fixation delayed fracture union. While we recommend intramedullary devices for open fractures, in our setting where locking nails are not readily available, external fixation remains the safest choice of skeletal stabilization particularly when contamination is high. PMID:23271839

Outcomes of Internal Fixation in a Combat Environment

DTIC Science & Technology

2010-01-01

analyzed. Forty-seven patients had internal fixation performed on 50 fractures in a combat theater hospital. Hip, forearm, and ankle fractures made up the...limited number of fracture patterns associated with a significant risk of failure if definitive treatment is delayed (4). Because of the limited...Injuries Hip, forearm, and ankle fractures made up the majority of internal fixation cases with 14 (28%), 14 (28%), and 10 TABLE 1 Mechanism of

Non union of an epiphyseal fibular fracture in a pediatric patient.

PubMed

Mirmiran, Roya; Schuberth, John M

2006-01-01

There are few reports on delayed or nonunion in the pediatric ankle fracture. The authors present a case of a nonunion of a mid-epiphyseal fracture of the distal fibula, described as a type 7 pediatric fracture. Both the occurrence of this injury pattern and a nonunion has not been reported in the same patient. Operative reduction of the nonunion resulted in a satisfactory outcome.

Delayed union and nonunions: epidemiology, clinical issues, and financial aspects.

PubMed

Hak, David J; Fitzpatrick, Daniel; Bishop, Julius A; Marsh, J Lawrence; Tilp, Susanne; Schnettler, Reinhard; Simpson, Hamish; Alt, Volker

2014-06-01

Fracture healing is a critically important clinical event for fracture patients and for clinicians who take care of them. The clinical evaluation of fracture healing is based on both radiographic findings and clinical findings. Risk factors for delayed union and nonunion include patient dependent factors such as advanced age, medical comorbidities, smoking, non-steroidal anti-inflammatory use, various genetic disorders, metabolic disease and nutritional deficiency. Patient independent factors include fracture pattern, location, and displacement, severity of soft tissue injury, degree of bone loss, quality of surgical treatment and presence of infection. Established nonunions can be characterised in terms of biologic capacity, deformity, presence or absence of infection, and host status. Hypertrophic, oligotrophic and atrophic radiographic appearances allow the clinician to make inferences about the degree of fracture stability and the biologic viability of the fracture fragments while developing a treatment plan. Non-unions are difficult to treat and have a high financial impact. Indirect costs, such as productivity losses, are the key driver for the overall costs in fracture and non-union patients. Therefore, all strategies that help to reduce healing time with faster resumption of work and activities not only improve medical outcome for the patient, they also help reduce the financial burden in fracture and non-union patients. Copyright © 2014 Elsevier Ltd. All rights reserved.

Early prophylactic autogenous bone grafting in type III open tibial fractures.

PubMed

Kesemenli, Cumhur C; Kapukaya, Ahmet; Subaşi, Mehmet; Arslan, Huseyin; Necmioğlu, Serdar; Kayikçi, Cuma

2004-08-01

The authors report the results achieved in patients with type III open tibial fractures who underwent primary autogenous bone grafting at the time of debridement and skeletal stabilisation. Twenty patients with a mean age of 35.8 years (range, 24-55) were treated between 1996 and 1999. Eight fractures were type IIIA, 11 were type IIIB, and 1 was type IIIC. At the index procedure, wound debridement, external fixation and autogenous bone grafting with bone coverage were achieved. The mean follow-up period was 46 months (range, 34-55). The mean time to fixator removal was 21 weeks (range, 14-35), and the mean time to union was 28 weeks (range, 19-45). Skin coverage was achieved by a myocutaneous flap in 2 patients, late primary closure in 4, and split skin grafting in 14. One (5%) of the patients experienced delayed union, and 1 (5%) developed infection. In tibial type III open fractures, skin coverage may be delayed, using the surrounding soft tissue to cover any exposed bone after thorough débridement and wound cleansing. Primary prophylactic bone grafting performed at the same time reduces the rate of delayed union, shortens the time to union, and does not increase the infection rate.

Risk Factors for Injury and Cigarette Smoking and Temporal Trends in Demographic and Lifestyle Characteristics Among U.S. Army Ordinance School Students

DTIC Science & Technology

2008-07-01

took 166 ± 92 days or had a 24% slower healing time to clinical union , compared with nonsmokers at 134 ± 71 days. Possible attributes of the delayed ...1993). Are smokers a risk group for delayed healing of tibial shaft fractures . Annales Chirurgiae et Gynaeacologiae, 82:254-262. 47. Mazess R...experience stress fractures , compared with Caucasians(29), possibly because Blacks having a higher bone density(30,31).Other studies performed

[Intramedullary nailing of the distal tibia illustrated with the Expert(TM) tibia nail].

PubMed

El Attal, R; Hansen, M; Rosenberger, R; Smekal, V; Rommens, P M; Blauth, M

2011-12-01

Restoration of axis, length, and rotation of the lower leg. Sufficient primary stability of the osteosynthesis for functional aftercare and to maintain joint mobility. Good bony healing in closed and open fractures. Closed and open fractures of the tibia and complete lower leg fractures distal to the isthmus (AO 42), extraarticular fractures of the distal tibia (AO 43 A1/A2/A3), segmental fractures of the tibia with a fracture in the distal tibia, and certain intraarticular fractures of the distal tibia without impression of the joint line with the use of additional implants (AO 43 C1) Patient in reduced general condition (e.g., bed ridden), flexion of the knee of less than 90°, patients with knee arthroplasty of the affected leg, infection in the area of the nail's insertion, infection of the tibial cavity, complex articular fractures of the proximal or distal tibia with joint depression. Closed reduction of the fracture preferably on a fracture table or using a distractor or an external fixation frame. If necessary, use pointed reduction clamps or sterile drapery. In some cases, additional implants like percutaneous small fragment screws, poller screws or k-wires are helpful. Open reduction is rarely necessary and must be avoided. Opening of the proximal tibia in line with the medullary canal. Canulated insertion of the Expert(TM) tibia nail (ETN; Synthes GmbH, Oberdorf, Switzerland) with reaming of the medullary canal. Control of axis, length, and rotation. Distal interlocking with the radiolucent drill and proximal interlocking with the targeting device. Immediate mobilization of ankle and knee joint. Mobilization with 20 kg weight-bearing with crutches. X-ray control 6 weeks postoperatively and increased weight-bearing depending on the fracture status. In cases with simple fractures, good bony contact, or transverse fracture pattern, full weight-bearing at the end of week 6 is targeted. Between July 2004 and May 2005, 180 patients were included in a multicenter study. The follow-up rate was 81% after 1 year. Of these, 91 fractures (50.6%) were located in the distal third of the tibia. In this segment, the rate of delayed union was 10.6%. Malalignment of > 5° was observed in 5.4%. A secondary malalignment after initial good reduction was detected in only 1.1% of all cases. The implant-specific risk for screw breakage was 3.2%. One patient sustained a deep infection. If additional fibula plating was performed an 8-fold higher risk for delayed bone healing was observed (95%CI: 2.9-21.2, p< 0.001). If the fracture of the fibula was at the same height as on the tibia, the risk for delayed healing was even 14-fold (95% CI: 3.4-62.5, p< 0.001). Biomechanically plating of the fibula does not increase stability in suprasyndesmal distal tibia-fibular fractures treated with an intramedullary nail. Using the ETN with its optimized locking options, fibula plating is not recommended, thus, avoiding soft tissue problems and potentially delayed bone healing.

[Cohort study on the prevalence and risk factors of late pulmonary complications in adults following a closed minor chest trauma].

PubMed

Plourde, Miville; Émond, Marcel; Lavoie, André; Guimont, Chantal; Le Sage, Natalie; Chauny, Jean-Marc; Bergeron, Éric; Vanier, Laurent; Moore, Lynne; Allain-Boulé, Nadine; Fratu, Ramona-Florina; Dufresne, Maryline

2013-11-01

The objectives of this study are to determine the prevalence, risk factors, and time to onset of delayed hemothorax and pneumothorax in adults who experienced a minor blunt thoracic trauma. A prospective cohort of 450 consecutive patients was recruited. Eligible patients had to be over 16 years of age, consulted within 72 hours for a trauma, and available for outpatient follow-up at 2, 7, and 14 days posttrauma. The clinical outcome investigated was the presence of delayed pneumothorax or hemothorax on the follow-up chest x-ray. Delayed hemothorax occurred in 11.8% (95% CI 8.8-14.8), and delayed pneumothorax occurred in 0.9% (95% CI 0.2-2.3) of participants. During the 14-day follow-up period, 87.0% of these delayed complications developed in the first week. In the multivariate analysis, the only statistically significant risk factor for delayed complications was the location of fractures on the x-ray of the hemithorax. The adjusted odds ratio was 1.52 (95% CI 0.62-3.73) for the lower ribs (tenth to twelfth rib), 3.11 (95% CI 1.60-6.08) for the midline ribs (sixth to ninth rib), and 5.05 (95% CI 1.80-14.19) for the upper ribs (third to fifth rib) versus patients with no fractures. The presence of at least one rib fracture between the third and ninth rib on the x-ray of the hemithorax is a significant risk factor for delayed hemothorax and pneumothorax.

Delayed Union of a Jones Fracture in a Patient With Rothmund-Thomson Syndrome: A Case Report and Review of the Literature.

PubMed

Barisonek, Kirsten L; Protzman, Nicole M; Wobst, Garrett M; Brigido, Stephen A

2016-01-01

Rothmund-Thomson syndrome is a rare autosomal recessive genodermatosis, characterized by poikiloderma, small stature, juvenile cataracts, sparse hair, skeletal abnormalities, and a predisposition to osteogenic sarcomas and skin cancers. Although numerous skeletal abnormalities have been described in patients with Rothmund-Thomson syndrome, to our knowledge, only 1 study has shown evidence of delayed fracture healing in a patient with Rothmund-Thomson syndrome. We present the case of a 13-year-old female diagnosed with Rothmund-Thomson syndrome who demonstrated delayed union of her fifth metatarsal after a Jones fracture. She was treated conservatively for 6 weeks with non-weightbearing cast immobilization and was then transitioned to a controlled ankle motion walker for an additional 4 weeks. Two months later, however, she continued to experience pain, and, on radiographic examination, the fracture remained unchanged. Therefore, with her guardian's consent, the patient elected to undergo open reduction and internal fixation of the fifth metatarsal fracture. At 8 weeks postoperatively, the patient reported a subsidence of symptoms and had returned to normal activity. With our report, we hope to increase practitioner awareness that delayed bone healing could be a possibility in patients with Rothmund-Thomson syndrome and encourage consideration of routine imaging and supplementation with calcium and vitamin D. Additionally, the present findings suggest that patients with Rothmund-Thomson syndrome could benefit from early surgical intervention, given their poor bone healing capacity and high likelihood of nonunion. Although the association between impaired bone healing and Rothmund-Thomson syndrome is rational, additional studies are needed to determine the prevalence of chronic nonunion in this patient population. Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Delayed Expression of Circulating TGF-β1 and BMP-2 Levels in Human Nonunion Long Bone Fracture Healing.

PubMed

Hara, Yoshiaki; Ghazizadeh, Mohammad; Shimizu, Hajime; Matsumoto, Hisashi; Saito, Nobuyuki; Yagi, Takanori; Mashiko, Kazuki; Mashiko, Kunihiro; Kawai, Makoto; Yokota, Hiroyuki

2017-01-01

The healing process of bone fracture requires a well-controlled multistage and sequential order beginning immediately after the injury. However, complications leading to nonunion exist, creating serious problems and costs for patients. Transforming growth factor-beta 1 (TGF-β1) and bone morphogenic protein 2 (BMP-2) are two major growth factors involved in human bone fracture healing by promoting various stages of bone ossification. In this study, we aimed to determine the role of these factors during the fracture healing of human long bones and assess their impacts on nonunion condition. We performed a comprehensive analysis of plasma TGF-β1 and BMP-2 levels in blood samples from 10 patients with proved nonunion and 10 matched patients with normal union following a predetermined time schedule. The concentrations of TGF-β1 and BMP-2 were measured at each time point using a solid-phase ELISA. TGF-β1 and BMP-2 levels were detectable in all patients. For all patients, a maximal peak for TGF-β1 was found at 3-week. In normal union group, TGF-β1 showed a maximal peak at 2-week while nonunion group had a delayed maximal peak at 3-week. Plasma levels of BMP-2 for all patients and for normal union group reached a maximal peak at 1-week, but nonunion group showed a delayed maximal peak at 2-week. In general, plasma TGF-β1 or BMP-2 level was not significantly different between normal union and nonunion groups. The expression levels of TGF-β1 and BMP-2 appeared to be delayed in nonunion patients which could play an important role in developing an early marker of fracture union condition and facilitate improved patient's management.

Locking plate fixation in distal metaphyseal tibial fractures: series of 79 patients.

PubMed

Gupta, Rakesh K; Rohilla, Rajesh Kumar; Sangwan, Kapil; Singh, Vijendra; Walia, Saurav

2010-12-01

Open reduction and internal fixation in distal tibial fractures jeopardises fracture fragment vascularity and often results in soft tissue complications. Minimally invasive osteosynthesis, if possible, offers the best possible option as it permits adequate fixation in a biological manner. Seventy-nine consecutive adult patients with distal tibial fractures, including one patient with a bilateral fracture of the distal tibia, treated with locking plates, were retrospectively reviewed. The 4.5-mm limited-contact locking compression plate (LC-LCP) was used in 33 fractures, the metaphyseal LCP in 27 fractures and the distal medial tibial LCP in the remaining 20 fractures. Fibula fixation was performed in the majority of comminuted fractures (n = 41) to maintain the second column of the ankle so as to achieve indirect reduction and to prevent collapse of the fracture. There were two cases of delayed wound breakdown in fractures fixed with the 4.5-mm LC-LCP. Five patients required primary bone grafting and three patients required secondary bone grafting. All cases of delayed union (n = 7) and nonunion (n = 3) were observed in cases where plates were used in bridge mode. Minimally invasive plate osteosynthesis (MIPO) with LCP was observed to be a reliable method of stabilisation for these fractures. Peri-operative docking of fracture ends may be a good option in severely impacted fractures with gap. The precontoured distal medial tibial LCP was observed to be a better tolerated implant in comparison to the 4.5-mm LC-LCP or metaphyseal LCP with respect to complications of soft tissues, bone healing and functional outcome, though its contour needs to be modified.

Lower limb stress fractures in sport: Optimising their management and outcome

PubMed Central

Robertson, Greg A J; Wood, Alexander M

2017-01-01

Stress fractures in sport are becoming increasing more common, comprising up to 10% of all of sporting injuries. Around 90% of such injuries are located in the lower limb. This articles aims to define the optimal management of lower limb stress fractures in the athlete, with a view to maximise return rates and minimise return times to sport. Treatment planning of this condition is specific to the location of the injury. However, there remains a clear division of stress fractures by “high” and “low” risk. “Low risk” stress fractures are those with a low probability of fracture propagation, delayed union, or non-union, and so can be managed reliably with rest and exercise limitation. These include stress fractures of the Postero-Medial Tibial Diaphysis, Metatarsal Shafts, Distal Fibula, Medial Femoral Neck, Femoral Shaft and Calcaneus. “High risk” stress fractures, in contrast, have increased rates of fracture propagation, displacement, delayed and non-union, and so require immediate cessation of activity, with orthopaedic referral, to assess the need for surgical intervention. These include stress fractures of the Anterior Tibial Diaphysis, Fifth Metatarsal Base, Medial Malleolus, Lateral Femoral Neck, Tarsal Navicular and Great Toe Sesamoids. In order to establish the optimal methods for managing these injuries, we present and review the current evidence which guides the treatment of stress fractures in athletes. From this, we note an increased role for surgical management of certain high risk stress fractures to improve return times and rates to sport. Following this, key recommendations are provided for the management of the common stress fracture types seen in the athlete. Five case reports are also presented to illustrate the application of sport-focussed lower limb stress fracture treatment in the clinical setting. PMID:28361017

The structure and effect of suture zones in the Larsen C Ice Shelf, Antarctica

NASA Astrophysics Data System (ADS)

McGrath, Daniel; Steffen, Konrad; Holland, Paul R.; Scambos, Ted; Rajaram, Harihar; Abdalati, Waleed; Rignot, Eric

2014-03-01

Ice shelf fractures frequently terminate where they encounter suture zones, regions of material heterogeneity that form between meteoric inflows in ice shelves. This heterogeneity can consist of marine ice, meteoric ice with modified rheological properties, or the presence of fractures. Here, we use radar observations on the Larsen C Ice Shelf, Antarctica, to investigate (i) the termination of a 25 km long rift in the Churchill Peninsula suture zone, which was found to contain 60 m of accreted marine ice, and (ii) the along-flow evolution of a suture zone originating at Cole Peninsula. We determine a steady state field of basal melting/freezing rates and apply it to a flowline model to delineate the along-flow evolution of layers within the ice shelf. The thickening surface wedge of locally accumulated meteoric ice, which likely has limited lateral variation in its mechanical properties, accounts for 60% of the total ice thickness near the calving front. Thus, we infer that the lower 40% of the ice column and the material heterogeneities present there are responsible for resisting fracture propagation and thereby delaying tabular calving events, as demonstrated in the >40 year time series leading up to the 2004/2005 calving event for Larsen C. This likely represents a highly sensitive aspect of ice shelf stability, as changes in the oceanic forcing may lead to the loss of this heterogeneity.

The ameloblastin extracellular matrix molecule enhances bone fracture resistance and promotes rapid bone fracture healing.

PubMed

Lu, Xuanyu; Li, Wenjin; Fukumoto, Satoshi; Yamada, Yoshihiko; Evans, Carla A; Diekwisch, Tom; Luan, Xianghong

2016-01-01

The extracellular matrix (ECM) provides structural support, cell migration anchorage, cell differentiation cues, and fine-tuned cell proliferation signals during all stages of bone fracture healing, including cartilaginous callus formation, callus remodeling, and bony bridging of the fracture gap. In the present study we have defined the role of the extracellular matrix protein ameloblastin (AMBN) in fracture resistance and fracture healing of mouse long bones. To this end, long bones from WT and AMBN(Δ5-6) truncation model mice were subjected to biomechanical analysis, fracture healing assays, and stem cell colony formation comparisons. The effect of exogenous AMBN addition to fracture sites was also determined. Our data indicate that lack of a functional AMBN in the bone matrix resulted in 31% decreased femur bone mass and 40% reduced energy to failure. On a cellular level, AMBN function inhibition diminished the proliferative capacity of fracture repair callus cells, as evidenced by a 58% reduction in PCNA and a 40% reduction in Cyclin D1 gene expression, as well as PCNA immunohistochemistry. In terms of fracture healing, AMBN truncation was associated with an enhanced and prolonged chondrogenic phase, resulting in delayed mineralized tissue gene expression and delayed ossification of the fracture repair callus. Underscoring a role of AMBN in fracture healing, there was a 6.9-fold increase in AMBN expression at the fracture site one week after fracture, and distinct AMBN immunolabeling in the fracture gap. Finally, application of exogenous AMBN protein to bone fracture sites accelerated callus formation and bone fracture healing (33% increase in bone volume and 19% increase in bone mineral density), validating the findings of our AMBN loss of function studies. Together, these data demonstrate the functional importance of the AMBN extracellular matrix protein in bone fracture prevention and rapid fracture healing. Copyright © 2016 International Society of Matrix Biology. Published by Elsevier B.V. All rights reserved.

The Ameloblastin extracellular matrix molecule enhances bone fracture resistance and promotes rapid bone fracture healing

PubMed Central

Lu, Xuanyu; Li, Wenjin; Fukumoto, Satoshi; Yamada, Yoshihiko; Evans, Carla; Diekwisch, Thomas G.H.; Luan, Xianghong

2016-01-01

The extracellular matrix (ECM) provides structural support, cell migration anchorage, cell differentiation cues, and fine-tuned cell proliferation signals during all stages of bone fracture healing, including cartilaginous callus formation, callus remodeling, and bony bridging of the fracture gap. In the present study we have defined the role of the extracellular matrix protein ameloblastin (AMBN) in fracture resistance and fracture healing of mouse long bones. To this end, long bones from WT and AMBNΔ5-6 truncation model mice were subjected to biomechanical analysis, fracture healing assays, and stem cell colony formation comparisons. The effect of exogenous AMBN addition to fracture sites was also determined. Our data indicate that lack of a functional AMBN in the bone matrix resulted in 31% decreased femur bone mass and 40% reduced energy to failure. On a cellular level, AMBN function inhibition diminished the proliferative capacity of fracture repair callus cells, as evidenced by a 58% reduction in PCNA and a 40% reduction in Cyclin D1 gene expression, as well as PCNA immunohistochemistry. In terms of fracture healing, AMBN truncation was associated with an enhanced and prolonged chondrogenic phase, resulting in delayed mineralized tissue gene expression and delayed ossification of the fracture repair callus. Underscoring a role of AMBN in fracture healing, there was a 6.9-fold increase in AMBN expression at the fracture site one week after fracture, and distinct AMBN immunolabeling in the fracture gap. Finally, application of exogenous AMBN protein to bone fracture sites accelerated callus formation and bone fracture healing (33% increase in bone volume and 19% increase in bone mineral density), validating the findings of our AMBN loss of function studies. Together, these data demonstrate the functional importance of the AMBN extracellular matrix protein in bone fracture prevention and rapid fracture healing. PMID:26899203

Internal fracture heterogeneity in discrete fracture network modelling: Effect of correlation length and textures with connected and disconnected permeability field

NASA Astrophysics Data System (ADS)

Frampton, A.; Hyman, J.; Zou, L.

2017-12-01

Analysing flow and transport in sparsely fractured media is important for understanding how crystalline bedrock environments function as barriers to transport of contaminants, with important applications towards subsurface repositories for storage of spent nuclear fuel. Crystalline bedrocks are particularly favourable due to their geological stability, low advective flow and strong hydrogeochemical retention properties, which can delay transport of radionuclides, allowing decay to limit release to the biosphere. There are however many challenges involved in quantifying and modelling subsurface flow and transport in fractured media, largely due to geological complexity and heterogeneity, where the interplay between advective and dispersive flow strongly impacts both inert and reactive transport. A key to modelling transport in a Lagrangian framework involves quantifying pathway travel times and the hydrodynamic control of retention, and both these quantities strongly depend on heterogeneity of the fracture network at different scales. In this contribution, we present recent analysis of flow and transport considering fracture networks with single-fracture heterogeneity described by different multivariate normal distributions. A coherent triad of fields with identical correlation length and variance are created but which greatly differ in structure, corresponding to textures with well-connected low, medium and high permeability structures. Through numerical modelling of multiple scales in a stochastic setting we quantify the relative impact of texture type and correlation length against network topological measures, and identify key thresholds for cases where flow dispersion is controlled by single-fracture heterogeneity versus network-scale heterogeneity. This is achieved by using a recently developed novel numerical discrete fracture network model. Furthermore, we highlight enhanced flow channelling for cases where correlation structure continues across intersections in a network, and discuss application to realistic fracture networks using field data of sparsely fractured crystalline rock from the Swedish candidate repository site for spent nuclear fuel.

Bisphosphonates and Nonhealing Femoral Fractures: Analysis of the FDA Adverse Event Reporting System (FAERS) and International Safety Efforts

PubMed Central

Edwards, Beatrice J.; Bunta, Andrew D.; Lane, Joseph; Odvina, Clarita; Rao, D. Sudhaker; Raisch, Dennis W.; McKoy, June M.; Omar, Imran; Belknap, Steven M.; Garg, Vishvas; Hahr, Allison J.; Samaras, Athena T.; Fisher, Matthew J.; West, Dennis P.; Langman, Craig B.; Stern, Paula H.

2013-01-01

Background: In the United States, hip fracture rates have declined by 30% coincident with bisphosphonate use. However, bisphosphonates are associated with sporadic cases of atypical femoral fracture. Atypical femoral fractures are usually atraumatic, may be bilateral, are occasionally preceded by prodromal thigh pain, and may have delayed fracture-healing. This study assessed the occurrence of bisphosphonate-associated nonhealing femoral fractures through a review of data from the U.S. FDA (Food and Drug Administration) Adverse Event Reporting System (FAERS) (1996 to 2011), published case reports, and international safety efforts. Methods: We analyzed the FAERS database with use of the proportional reporting ratio (PRR) and empiric Bayesian geometric mean (EBGM) techniques to assess whether a safety signal existed. Additionally, we conducted a systematic literature review (1990 to February 2012). Results: The analysis of the FAERS database indicated a PRR of 4.51 (95% confidence interval [CI], 3.44 to 5.92) for bisphosphonate use and nonhealing femoral fractures. Most cases (n = 317) were attributed to use of alendronate (PRR = 3.32; 95% CI, 2.71 to 4.17). In 2008, international safety agencies issued warnings and required label changes. In 2010, the FDA issued a safety notification, and the American Society for Bone and Mineral Research (ASBMR) issued recommendations about bisphosphonate-associated atypical femoral fractures. Conclusions: Nonhealing femoral fractures are unusual adverse drug reactions associated with bisphosphonate use, as up to 26% of published cases of atypical femoral fractures exhibited delayed healing or nonhealing. PMID:23426763

The use of weightbearing radiographs to assess the stability of supination-external rotation fractures of the ankle.

PubMed

Weber, Martin; Burmeister, Helge; Flueckiger, Gerhard; Krause, Fabian G

2010-05-01

Isolated lateral malleolar fractures usually result from a supination-external rotation (SER) injury and may include a deltoid ligament rupture. The necessity of operative treatment is based on the recognition of a relevant medial soft-tissue disruption. Currently used tests to assess ankle stability include manual stress radiographs and gravity stress radiographs, but seem to overestimate the need for fracture fixation. We investigated the use of weightbearing radiographs to distinguish stable and unstable isolated lateral malleolar fractures induced by the SER mechanism in 57 patients. Patients with stable fractures (SER type II according to the Lauge-Hansen classification) were treated non-operatively with varying external support. Forty-seven patients were evaluated by questionnaire and AOFAS ankle-hindfoot score. Follow-up was 18-120 months (mean 62). Fifty-one of fifty-seven (90%) patients were found to have stable fractures (SER type II) and were treated nonoperatively. The AOFAS score was 96.1 points on average (range 85-100) at latest follow-up. Four patients reported minor complaints. A "moderate" correlation of risk factors (i.e. smoking) to delayed bone healing was found while the correlation of varying external support (i.e. bandage, cast) to the AOFAS score and delayed bone healing was "poor". The use of weightbearing radiographs is an easy, pain-free, safe and reliable method to exclude the need for operative treatment, with excellent clinical outcome in the majority of the patients seen at latest follow-up. The delay of 3-10 days until the decision about surgical treatment is well accepted by the patients.

Extracorporeal shock wave treatment of non- or delayed union of proximal metatarsal fractures.

PubMed

Alvarez, Richard G; Cincere, Brandon; Channappa, Chandra; Langerman, Richard; Schulte, Robert; Jaakkola, Juha; Melancon, Keith; Shereff, Michael; Cross, G Lee

2011-08-01

Nonunion or delayed union of fractures in the proximal aspect of metatarsals 1 to 4 and Zone 2 of the fifth metatarsal were treated by high energy extracorporeal shock wave treatment (ESWT) to study the safety and efficacy of this method of treatment in a FDA study of the Ossatron device. In a prospective single-arm, multi-center study, 34 fractures were treated in 32 patients (two subjects had two independent fractures) with ESWT. All fractures were at least 10 (range, 10 to 833) weeks after injury, with a median of 23 weeks. ESWT application was conducted using a protocol totaling 2,000 shocks for a total energy application of approximately 0.22 to 0.51 mJ/mm2 per treatment. The mean ESWT application time for each of the treatments was 24.6 +/- 16.6 minutes, and anesthesia time averaged 27.1 +/- 10.4 minutes. All subjects were followed for 1 year after treatment at intervals of 12 weeks, 6, 9, and 12 months. The overall success rate at the 12-week visit was 71% with low complications, significant pain improvement as well as improvement on the SF-36. The success/fail criteria was evaluated again at the 6- and 12-month followup, showing treatment success rates of 89% (23/26) and 90% (18/20), respectively. The most common adverse event was swelling in the foot, reported by five subjects (15.6%). High-energy ESWT appears to be effective and safe in patients for treatment of nonunion or a delayed healing of a proximal metatarsal, and in fifth metatarsal fractures in Zone 2.

Mandibular fractures in India during the Second World War (1944 and 1945): analysis of the Snawdon series.

PubMed

Chambers, I G; Scully, C

1987-10-01

The records of Major J. W. E. Snawdon of the No. 2 Indian Maxillofacial Unit provide a rare and detailed insight into the treatment of mandibular fractures during the Second World War. Notable features were the high frequency of civilian-type injuries, the considerable delays between injury and definitive treatment, the lengthy periods of intermaxillary fixation required, the high incidence of infections and the common occurrence of delayed union. Despite these problems, only 12% of fractures resulted in non-union, usually when these were missile injuries with considerable destruction. Reporting of the details from Snawdon's records should be of interest particularly to young oral surgeons, whose experience of trauma belongs to an entirely different environment.

Fracture healing: a consensus report from the International Osteoporosis Foundation Fracture Working Group.

PubMed

Silverman, S L; Kupperman, E S; Bukata, S V

2016-07-01

We used the RAND UCLA appropriateness method to decide appropriateness of use of osteoporosis medication after incident fracture and potential for fracture healing and make suggestions for trial design for clinical and preclinical research. To develop appropriateness criteria to assist in the use and study of osteoporosis medications in patients with recent fracture and in the potential use of osteoporosis medications to enhance delayed fracture healing. To promote further research by suggesting preclinical and clinical trial design for studies where fracture healing is the endpoint. RAND/UCLA appropriateness method (RUAM). A panel of experts, both members and non-members of the International Osteoporosis Foundation Fracture Working Group, were identified consisting of geriatricians, rheumatologists, orthopedists, endocrinologists, and internists. This resulted in a round 1 panel of 15 panelists, round 2 panel of 15 members, and a round 3 panel of 14 members. Agreement on statements and scenarios using RUAM. Three rounds of voting by panelists took place. Agreement in a third round was reached for 111 statements and scenarios, measured by median panel ratings and the amount of dispersion of panel ratings, based on the interpercentile range. An expert panel validated a set of statements and scenarios about the use of osteoporosis medications after incident fracture and use of these medications to enhance delayed fracture healing and made recommendations for study designs to investigate the effect of osteoporosis medications on fracture healing. The result of this exercise is intended to assist in improving patient care by identifying the appropriateness of use of osteoporosis medications after fracture and in fracture healing and to make suggestions for further preclinical and clinical research.

Genetic factors responsible for long bone fractures non-union.

PubMed

Szczęsny, Grzegorz; Olszewski, Waldemar L; Zagozda, Małgorzata; Rutkowska, Joanna; Czapnik, Zanetta; Swoboda-Kopeć, Ewa; Górecki, Andrzej

2011-02-01

Approximately 10-15% of all fractures of long bones heal with delay, prolonged immobilization and repetitive operative interventions. Despite intense investigations, the pathomechanism of impaired healing of skeletal tissue remains unclear. An important role in the pathomechanism of mal-union of close fractures plays subclinically proceeding infections. The question arises whether colonization and proliferation of bacteria in the fracture gap could be related to the mutation of genes for factors regulating local antimicrobial response, such as pathogen recognizing receptors (PRR), cytokines and chemokines. We carried out studies in patients with delayed long bone fractures estimating the frequency of mutation of genes crucial for pathogen recognition (TLR2, TLR4 and CD14), and elimination (CRP, IL-6, IL-1ra), as well as wound healing (TGF-β). The molecular milieu regulating healing process (IGF-1, COLL1a, TGF-β, BMP-2, and PDGF) was validated by Western blot analysis of the gap tissue. Microbiological investigations showed the presence of viable bacterial strains in 34 out of 108 gaps in patients with non-healing fractures (31.5%) and in 20 out of 122 patients with uneventful healing (16.4%) (P < 0.05). The occurrence of mutated TLR4 1/W but not 2/W gene was significantly higher (P < 0.05) in the non-healing infected than sterile group. In the non-healing infected group 1/W mutated gene frequency was also higher than in healing infected. In the TGF-β codon 10 a significantly higher frequency of mutated homozygote T and heterozygote C/T in the non-healing infected versus non-healing sterile subgroup was observed (P < 0.05). Similar difference was observed in the non-healing infected versus healing infected subgroup (P < 0.05). The CRP (G1059C), IL1ra (genotype 2/2), IL-6 (G176C), CD14 (G-159T), TLR2 (G2259A) and TLR4/2 (Thr399Ile) polymorphisms did not play evident role in the delay of fracture healing. Individuals bearing the mutant TLR 4 gene 1/W (Asp299Gly) and TGF-β gene codon 10 mutant T and T/C allele may predispose to impaired pathogen recognition and elimination, leading to prolonged pathogen existence in the fracture gaps and healing delays.

Design and Optimization of an Austenitic TRIP Steel for Blast and Fragment Protection

NASA Astrophysics Data System (ADS)

Feinberg, Zechariah Daniel

In light of the pervasive nature of terrorist attacks, there is a pressing need for the design and optimization of next generation materials for blast and fragment protection applications. Sadhukhan used computational tools and a systems-based approach to design TRIP-120---a fully austenitic transformation-induced plasticity (TRIP) steel. Current work more completely evaluates the mechanical properties of the prototype, optimizes the processing for high performance in tension and shear, and builds models for more predictive power of the mechanical behavior and austenite stability. Under quasi-static and dynamic tension and shear, the design exhibits high strength and high uniform ductility as a result of a strain hardening effect that arises with martensitic transformation. Significantly more martensitic transformation occurred under quasi-static loading conditions (69% in tension and 52% in shear) compared to dynamic loading conditions (13% tension and 5% in shear). Nonetheless, significant transformation occurs at high-strain rates which increases strain hardening, delays the onset of necking instability, and increases total energy absorption under adiabatic conditions. Although TRIP-120 effectively utilizes a TRIP effect to delay necking instability, a common trend of abrupt failure with limited fracture ductility was observed in tension and shear at all strain rates. Further characterization of the structure of TRIP-120 showed that an undesired grain boundary cellular reaction (η phase formation) consumed the fine dispersion of the metastable gamma' phase and limited the fracture ductility. A warm working procedure was added to the processing of TRIP-120 in order to eliminate the grain boundary cellular reaction from the structure. By eliminating η formation at the grain boundaries, warm-worked TRIP-120 exhibits a drastic improvement in the mechanical properties in tension and shear. In quasi-static tension, the optimized warm-worked TRIP-120 with an Mssigma( u.t.) of -13°C has a yield strength of 180 ksi (1241 MPa), uniform ductility of 0.303, and fracture ductility of 0.95, which corresponds to a 48% increase in yield strength, a 43% increase in uniform ductility, and a 254% increase in fracture ductility relative to the designed processing of TRIP-120. The highest performing condition of warm-worked TRIP-120 in quasi-static shear with an Mssigma( sh) of 58°C exhibits a shear yield strength of 95.1 ksi (656 MPa), shear fracture strain of 144%, and energy dissipation density of 1099 MJ/m3, which corresponds to a shear yield strength increase of 61%, a shear fracture strain increase of 55%, and an energy dissipation density increase of 76%. A wide range of austenite stabilities can be achieved by altering the heat treatment times and temperatures, which significantly alters the mechanical properties. Although performance cannot be optimized for tension and shear simultaneously, different heat treatments can be applied to warm-worked TRIP-120 to achieve high performance in tension or shear. Parametric models calibrated with three-dimensional atom probe data played a crucial role in guiding the predictive process optimization of TRIP-120. Such models have been built to provide the predictive capability of inputting warm working and aging conditions and outputting the resulting structure, austenite stability, and mechanical properties. The predictive power of computational models has helped identify processing conditions that have improved the performance of TRIP-120 in tension and shear and can be applied to future designs that optimize for adiabatic conditions.

Fragility Hip Fractures in Elderly Patients in Bhubaneswar, India (2012-2014): A Prospective Multicenter Study of 1031 Elderly Patients.

PubMed

Dash, Sunil K; Panigrahi, Ranajit; Palo, Nishit; Priyadarshi, Ashok; Biswal, Manas

2015-03-01

Elderly patients with hip fracture constitute Single Largest Group of Emergency Orthopaedics Admissions. In 2050, 6.26 million hip fractures worldwide, approximately 50%, will occur in Asia. Only small number of reports on incidence of hip fractures in the Asian population exist. India lacks data registry for fragility hip fractures, therefore, the magnitude and standard of patient care are not known. A prospective multicenter study was conducted from January 2012 to April 2014 to describe population-based longitudinal trends, namely, age-specific incidence, fracture type, timing of presentation, kilometers traveled, timing of surgery, hospital stay, man hours lost, pressure ulcers, weight bearing, 30-day return, 3-month mortality, and so on, of fragility hip fractures. A total of 1031 patients were included with 59.7% females and 40.3% of male patients, with a female-male ratio of 1.5:1. Commonest mode: Falls 45%. 56.4% IT fractures. 66.2%patients operated, Operative/Conservative Ratio of 2.8:1. Patients travel a mean distance of 86.4 kilometers for quality treatment. Of the patients, 85.9 % presented late due to ignorance and misguiding quack practice. Incidence of delayed surgery was 69.3%. Persistent electrolytes imbalance and hyperglycemia normalized in 81.2% by second or third postoperative day. The man hours lost was 157.85 hours/person. Medical complications was more (90%) in patients who had delays in surgeries and presentation. Mortality rate was 6.2 %. Patients travel long for quality treatment, most of them are misguided, present late with significant complications and sufferings, and their pockets half drained depriving them off best treatment. Early presentation and operation have better prognosis and rehabilitation, facilitates early return to work, and independence. Increased pressure sores, infections, hospital stay, treatment cost, depression, and mortality are directly related to delays in surgeries and presentation. Estimated losses according to lost man hours may go up to 10 million dollars.

Ovariectomy-Induced Osteopenia Influences the Middle and Late Periods of Bone Healing in a Mouse Femoral Osteotomy Model.

PubMed

Pang, Jian; Ye, Meina; Gu, Xinfeng; Cao, Yuelong; Zheng, Yuxin; Guo, Hailing; Zhao, Yongfang; Zhan, Hongsheng; Shi, Yinyu

2015-08-01

It is known that bone healing is delayed in the presence of osteoporosis in humans. However, due to the complexities of the healing of osteoporotic fractures, animal models may be more appropriate for studying the effects of osteoporosis in more detail and for testing drugs on the fracture repair process. The purpose of this study was to investigate the influence of ovariectomy-induced osteopenia in bone healing in an open femoral osteotomy model, and to test the feasibility of this model for evaluating the healing process under osteopenic conditions. Ovariectomized (OVX) mouse models were employed to assess the effects of osteopenia on fracture healing, A mid-shaft femur osteotomy model was also established 3 weeks after ovariectomy as an osteopenic fracture group (OVX group). Femurs were then harvested at 2 weeks and 6 weeks after fracture for X-ray radiography, micro-computed tomography (micro-CT), histology, and biomechanical analysis. A sham-operated group (sham group) was used for comparison. The OVX mice had significantly lower bone volume density (BVF), volumetric bone mineral density (vBMD), and tissue mineral density (TMD) in the fracture calluses at 6 weeks (p<0.05), and similar trend was observed in 2 weeks. Additionally, larger calluses in OVX animals were observed via micro-CT and X-ray, but these did not result in better healing outcomes, as determined by biomechanical test at 6 weeks. Histological images of the healing fractures in the OVX mice found hastening of broken end resorption and delay of hard callus remodeling. The impaired biomechanical measurements in the OVX group (p<0.05) were consistent with micro-CT measurements and radiographic scoring, which also indicated delay in fracture healing of the OVX group. This study provided evidence that ovariectomy-induced osteopenia impair the middle and late bone healing process. These data also supported the validity of the mouse femoral osteotomy model in evaluating the process of bone healing under osteopenic conditions.

Ovariectomy-induced osteopenia influences the middle and late periods of bone healing in a mouse femoral osteotomy model.

PubMed

Pang, Jian; Ye, Meina; Cao, Yuelong; Zheng, Yuxin; Guo, Hailing; Zhao, Yongfang; Zhan, Hongsheng; Shi, Yinyu

2014-10-09

Objective It is known that bone healing was delayed in the presence of osteoporosis in humans. However, due to the complexities of the healing of osteoporotic fractures, animal models may be more appropriate to study the effects of osteoporosis in more details and to test drugs on the fracture repair process. The purpose of this study was to investigate the influence of ovariectomy-induced osteopenia in bone healing in an open femoral osteotomy model, and to test the feasibility of this model for evaluating the healing process under osteopenic conditions. Methods In assessing the effects of osteopenia on fracture healing, ovariectomized mouse models were employed. A mid-shaft femur osteotomy model was also established 3 weeks after ovariectomy as an osteopenic fracture group (OVX group). Femurs were then harvested at 2 weeks and 6 weeks after fracture for X-ray radiography, micro-computed tomography (micro-CT), histology and biomechanical analysis. A sham-operated group (Sham group) was used for comparison. Results The OVX mice had significantly lower BVF, vBMD and TMD in the fracture calluses at 6 weeks (P < 0.05), and similar trend was observed in 2 weeks. Additionally, larger calluses in OVX animals were observed via micro-CT and X-ray, but these did not result in better healing outcomes as determined by biomechanical test at 6 weeks. Histological images of the healing fractures in the OVX mice found forward of broken end resorption and delay of hard callus remodeling. The impaired biomechanical measurements in the OVX group (P < 0.05) were consistent with micro-CT measurements and radiographic scoring, which also indicated delay in fracture healing of the OVX group. Conclusions This study provided evidences that ovariectomy-induced osteopenia impair the middle and late bone healing process once more. These data also supported the validity of the mouse femoral osteotomy model in evaluating the process of bone healing under osteopenic conditions.

Delayed wound healing after tooth extraction and self-reported kyphosis in Japanese men and women

PubMed Central

Taguchi, Akira; Kamimura, Mikio; Nakamura, Yukio; Sugino, Noriyuki; Ichinose, Akira; Maezumi, Hisayoshi; Fukuzawa, Takashi; Ashizawa, Ryouhei; Takahara, Kenji; Gushiken, Susumu; Mukaiyama, Keijiro; Ikegami, Shota; Uchiyama, Shigeharu; Kato, Hiroyuki

2016-01-01

It is unclear whether osteoporosis itself is a main risk factor for delayed wound healing after tooth extraction in humans. In this study, we evaluated the association between experience of delayed wound healing after last tooth extraction and self-reported kyphosis, with the possibility of having vertebral fractures, in Japanese patients. Among the 1,504 patients who responded to the structured questionnaire survey, 518 patients (134 men and 384 women) aged 55–97 years finally participated in this study. Patients who self-reported mild-moderate kyphosis were more likely to have problematic delayed wound healing after last tooth extraction than those who reported severe kyphosis (odds ratio [OR] 4.98; 95% confidence interval [CI], 1.86–13.38 and OR 2.30; 95% CI, 0.52–10.22, respectively) (p for trend = 0.005). Japanese patients with vertebral fractures may have a higher risk of having problematic delayed wound healing after tooth extraction. PMID:27848958

Delayed wound healing after tooth extraction and self-reported kyphosis in Japanese men and women.

PubMed

Taguchi, Akira; Kamimura, Mikio; Nakamura, Yukio; Sugino, Noriyuki; Ichinose, Akira; Maezumi, Hisayoshi; Fukuzawa, Takashi; Ashizawa, Ryouhei; Takahara, Kenji; Gushiken, Susumu; Mukaiyama, Keijiro; Ikegami, Shota; Uchiyama, Shigeharu; Kato, Hiroyuki

2016-11-16

It is unclear whether osteoporosis itself is a main risk factor for delayed wound healing after tooth extraction in humans. In this study, we evaluated the association between experience of delayed wound healing after last tooth extraction and self-reported kyphosis, with the possibility of having vertebral fractures, in Japanese patients. Among the 1,504 patients who responded to the structured questionnaire survey, 518 patients (134 men and 384 women) aged 55-97 years finally participated in this study. Patients who self-reported mild-moderate kyphosis were more likely to have problematic delayed wound healing after last tooth extraction than those who reported severe kyphosis (odds ratio [OR] 4.98; 95% confidence interval [CI], 1.86-13.38 and OR 2.30; 95% CI, 0.52-10.22, respectively) (p for trend = 0.005). Japanese patients with vertebral fractures may have a higher risk of having problematic delayed wound healing after tooth extraction.

Experience with management of posterior urethral injury associated with pelvic fracture.

PubMed

Coffield, K S; Weems, W L

1977-06-01

Review of records from 205 patients with pelvic fracture and hematuria revealed that 121 underwent urologic and radiographic evaluation. Of these patients 20 had severe posterior urethral injuries documented by urethrography of voiding cystourethrography: 9 underwent primary repair and 11 had delayed scrotal-inlay urethroplasty after initial cystostomy alone. Patients who underwent primary repair had a 77 per cent incidence of stricture, a 22 per cent incidence of incontinence and a 33 per cent incidence of impotency. Patients who underwent delayed closure had no incidence of stricture, incontinence or impotence. Patients in both groups had urinary tract infections. Simple cystostomy followed by delayed scrotal-inlay urethroplasty appears superior to primary realignment in the management of patients with posterior urethral injuries.

High-Risk Stress Fractures: Diagnosis and Management.

PubMed

McInnis, Kelly C; Ramey, Lindsay N

2016-03-01

Stress fractures are common overuse injuries in athletes. They occur during periods of increased training without adequate rest, disrupting normal bone reparative mechanisms. There are a host of intrinsic and extrinsic factors, including biochemical and biomechanical, that put athletes at risk. In most stress fractures, the diagnosis is primarily clinical, with imaging indicated at times, and management focused on symptom-free relative rest with advancement of activity as tolerated. Overall, stress fractures in athletes have an excellent prognosis for return to sport, with little risk of complication. There is a subset of injuries that have a greater risk of fracture progression, delayed healing, and nonunion and are generally more challenging to treat with nonoperative care. Specific locations of high-risk stress fracture include the femoral neck (tension side), patella, anterior tibia, medial malleolus, talus, tarsal navicular, proximal fifth metatarsal, and great toe sesamoids. These sites share a characteristic region of high tensile load and low blood flow. High-risk stress fractures require a more aggressive approach to evaluation, with imaging often necessary, to confirm early and accurate diagnosis and initiate immediate treatment. Treatment consists of nonweight-bearing immobilization, often with a prolonged period away from sport, and a more methodic and careful reintroduction to athletic activity. These stress fractures may require surgical intervention. A high index of suspicion is essential to avoid delayed diagnosis and optimize outcomes in this subset of stress fractures. Copyright © 2016 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Comparison of surgical techniques of 111 medial malleolar fractures classified by fracture geometry.

PubMed

Ebraheim, Nabil A; Ludwig, Todd; Weston, John T; Carroll, Trevor; Liu, Jiayong

2014-05-01

Evaluation of operative techniques used for medial malleolar fractures by classifying fracture geometry has not been well documented. One hundred eleven patients with medial malleolar fractures (transverse n = 63, oblique n = 29, vertical n = 7, comminuted n = 12) were included in this study. Seventy-two patients had complicating comorbidities. All patients were treated with buttress plate, lag screw, tension band, or K-wire fixation. Treatment outcomes were evaluated on the basis of radiological outcome (union, malunion, delayed union, or nonunion), need for operative revision, presence of postoperative complications, and AOFAS Ankle-Hindfoot score. For transverse fractures, tension band fixation showed the highest rate of union (79%), highest average AOFAS score (86), lowest revision rate (5%), and lowest complication rate (16%). For oblique fractures, lag screws showed the highest rate of union (71%), highest average AOFAS score (80), lowest revision rate (19%), and lowest complication rate (33%) of the commonly used fixation techniques. For vertical fractures, buttress plating was used in every case but 1, achieving union (whether normal or delayed) in all cases with an average AOFAS score of 84, no revisions, and a 17% complication rate. Comminuted fractures had relatively poor outcomes regardless of fixation method. The results of this study suggest that both tension bands and lag screws result in similar rates of union for transverse fractures of the medial malleolus, but that tension band constructs are associated with less need for revision surgery and fewer complications. In addition, our data demonstrate that oblique fractures were most effectively treated with lag screws and that vertical fractures attained superior outcomes with buttress plating. Level III, retrospective comparative series.

5-year follow-up of a randomized controlled trial of immediate versus delayed zoledronic acid for the prevention of bone loss in postmenopausal women with breast cancer starting letrozole after tamoxifen: N03CC (Alliance) trial.

PubMed

Wagner-Johnston, Nina D; Sloan, Jeff A; Liu, Heshan; Kearns, Ann E; Hines, Stephanie L; Puttabasavaiah, Suneetha; Dakhil, Shaker R; Lafky, Jacqueline M; Perez, Edith A; Loprinzi, Charles L

2015-08-01

Postmenopausal women with breast cancer receiving aromatase inhibitors are at an increased risk of bone loss. The current study was undertaken to determine whether upfront versus delayed treatment with zoledronic acid (ZA) impacted bone loss. This report described the 5-year follow-up results. A total of 551 postmenopausal women with breast cancer who completed tamoxifen treatment and were undergoing daily letrozole treatment were randomized to either upfront (274 patients) or delayed (277 patients) ZA at a dose of 4 mg intravenously every 6 months. In the patients on the delayed treatment arm, ZA was initiated for a postbaseline bone mineral density T-score of <-2.0 or fracture. The incidence of a 5% decrease in the total lumbar spine bone mineral density at 5 years was 10.2% in the upfront treatment arm versus 41.2% in the delayed treatment arm (P<.0001). A total of 41 patients in the delayed treatment arm were eventually started on ZA. With the exception of increased NCI Common Toxicity Criteria (CTC) grade 1/2 elevated creatinine and fever in the patients treated on the upfront arm and cerebrovascular ischemia among those in the delayed treatment arm, there were no significant differences observed between arms with respect to the most common adverse events of arthralgia and back pain. Osteoporosis occurred less frequently in the upfront treatment arm (2 vs 8 cumulative cases), although this difference was not found to be statistically significant. Bone fractures occurred in 24 patients in the upfront treatment arm versus 25 patients in the delayed treatment arm. Immediate treatment with ZA prevented bone loss compared with delayed treatment in postmenopausal women receiving letrozole and these differences were maintained at 5 years. The incidence of osteoporosis or fractures was not found to be significantly different between treatment arms. © 2015 American Cancer Society.

Immediate management of posterior urethral disruptions due to pelvic fracture: therapeutic alternatives.

PubMed

Podestá, M L; Medel, R; Castera, R; Ruarte, A

1997-04-01

We retrospectively reviewed the results of 3 types of initial management of pelvic fracture urethral disruption in children. From 1980 to 1994, 35 boys 2 to 15 years old (mean age 8.1) with prostatomembranous urethral disruption were treated, including 17 who also had associated injuries. Immediate treatment included suprapubic cystostomy and delayed urethroplasty in 19 patients (group 1), urethral catheter alignment without traction and concomitant suprapubic cystostomy in 10 (group 2), and primary retropubic anastomotic urethroplasty in 6 (group 3). In all patients in groups 1 and 2 severe urethral obliteration developed. Four group 3 patients (66%) had a stricture at the site of anastomotic repair. After delayed urethroplasty 16 group 1 (84%) and all 10 group 2 patients were continent. However, only 3 group 3 patients (50%) achieved continence. Retrospectively associated bladder neck injury occurred in 5 of the 6 incontinent boys. Erections were observed before and after treatment in all but 3 children. Unstable pelvic ring fractures (type IV) comprised 28% of all pelvic fractures with a high rate of associated injuries. As described, urethral alignment was not beneficial for avoiding urethral obliteration. Therefore we recommend suprapublic cystostomy as the only form of initial treatment in these cases. Urinary incontinence seems more likely related to associated bladder neck rupture and the severity of pelvic fracture rather than to initial treatment or delayed urethral repair. Consequently, when associated bladder neck injury is present, we advocate immediate surgical repair.

Deformation and fracture of cross-linked polymer gels

NASA Astrophysics Data System (ADS)

Lin, Wei-Chun

Because soft materials, particularly polymer gels, are playing a greater role in industrial and biotechnological applications today, the exploration of their mechanical behavior over a range of deformations is becoming more relevant in our daily lives. Understanding these properties is therefore necessary as a means to predict their response for specific applications. To address these concerns, this dissertation presents a set of analytic tools based on flat punch probe indentation tests to predict the response of polymer gels from a mechanical perspective over a large range of stresses and at failure. At small strains, a novel technique is developed to determine the transport properties of gels based on their measured mechanical behavior. Assuming that a polymer gel behaves in a similar manner as a porous structure, the differentiation of solvent flow from viscoelasticity of a gel network is shown to be possible utilizing a flat, circular punch and a flat, rectangular punch under oscillatory conditions. Use of the technique is demonstrated with a poly(N-isopropyl acrylamide) (pNIPAM) hydrogel. Our results indicate that solvent flow is inhibited at temperatures above the critical solution temperature of 35°C. At high stresses and fracture, the flat probe punch indentation geometry is used to understand how the structure and geometry of silicone based gels affect their mechanical properties. A delayed failure response of the gels is observed and the modes of failure are found to be dependent on the geometry of the system. The addition of a sol fraction in these gels was found to toughen the network and play an important role at these large deformations. Potential mechanisms of fracture resistance are discussed, as is the effect of geometric confinement as it relates to large scale deformation and fracture. These results lay the groundwork for understanding the mechanical response of other highly, deformable material systems utilizing this particular geometry.

VEGF serum concentrations in patients with long bone fractures: a comparison between impaired and normal fracture healing.

PubMed

Sarahrudi, Kambiz; Thomas, Anita; Braunsteiner, Tomas; Wolf, Harald; Vécsei, Vilmos; Aharinejad, Seyedhossein

2009-10-01

Vascular endothelial growth factor (VEGF) plays an important role in the bone repair process as a potent mediator of angiogenesis and it influences directly osteoblast differentiation. Inhibiting VEGF suppresses angiogenesis and callus mineralization in animals. However, no data exist so far on systemic expression of VEGF with regard to delayed or failed fracture healing in humans. One hundred fourteen patients with long bone fractures were included in the study. Serum samples were collected over a period of 6 months following a standardized time schedule. VEGF serum concentrations were measured. Patients were assigned to one of two groups according to their course of fracture healing. The first group contained 103 patients with physiological fracture healing. Eleven patients with delayed or nonunions formed the second group of the study. In addition, 33 healthy volunteers served as controls. An increase of VEGF serum concentration within the first 2 weeks after fracture in both groups with a following decrease within 6 months after trauma was observed. Serum VEGF concentrations in patients with impaired fracture healing were higher compared to the patients with physiological healing during the entire observation period. However, statistically significant differences were not observed at any time point between both groups. VEGF concentrations in both groups were significantly higher than those in controls. The present results show significantly elevated serum concentrations of VEGF in patients after fracture of long bones especially at the initial healing phase, indicating the importance of VEGF in the process of fracture healing in humans. (c) 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Technical considerations for surgical intervention of Jones fractures.

PubMed

Mendicino, Robert W; Hentges, Matthew J; Mendicino, Michael R; Catanzariti, Alan R

2013-01-01

Jones fractures are a common injury treated by foot and ankle surgeons. Surgical intervention is recommended because of the high rate of delayed union, nonunion, and repeat fracture, when treated conservatively. Percutaneous intramedullary screw fixation is commonly used in the treatment of these fractures. We present techniques that can increase the surgical efficiency and decrease the complications associated with percutaneous delivery of internal fixation. Copyright © 2013 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Site Specific Effects of Zoledronic Acid during Tibial and Mandibular Fracture Repair

PubMed Central

Yu, Yan Yiu; Lieu, Shirley; Hu, Diane; Miclau, Theodore; Colnot, Céline

2012-01-01

Numerous factors can affect skeletal regeneration, including the extent of bone injury, mechanical loading, inflammation and exogenous molecules. Bisphosphonates are anticatabolic agents that have been widely used to treat a variety of metabolic bone diseases. Zoledronate (ZA), a nitrogen-containing bisphosphonate (N-BP), is the most potent bisphosphonate among the clinically approved bisphosphonates. Cases of bisphosphonate-induced osteonecrosis of the jaw have been reported in patients receiving long term N-BP treatment. Yet, osteonecrosis does not occur in long bones. The aim of this study was to compare the effects of zoledronate on long bone and cranial bone regeneration using a previously established model of non-stabilized tibial fractures and a new model of mandibular fracture repair. Contrary to tibial fractures, which heal mainly through endochondral ossification, mandibular fractures healed via endochondral and intramembranous ossification with a lesser degree of endochondral ossification compared to tibial fractures. In the tibia, ZA reduced callus and cartilage formation during the early stages of repair. In parallel, we found a delay in cartilage hypertrophy and a decrease in angiogenesis during the soft callus phase of repair. During later stages of repair, ZA delayed callus, cartilage and bone remodeling. In the mandible, ZA delayed callus, cartilage and bone remodeling in correlation with a decrease in osteoclast number during the soft and hard callus phases of repair. These results reveal a more profound impact of ZA on cartilage and bone remodeling in the mandible compared to the tibia. This may predispose mandible bone to adverse effects of ZA in disease conditions. These results also imply that therapeutic effects of ZA may need to be optimized using time and dose-specific treatments in cranial versus long bones. PMID:22359627

Predictors of hip fracture mortality at a general hospital in South Brazil: an unacceptable surgical delay

PubMed Central

Ribeiro, Tiango Aguiar; Premaor, Melissa Orlandin; Larangeira, João Alberto; Brito, Luiz Giulian; Luft, Michel; Guterres, Leonardo Waihrich; Monticielo, Odirlei André

2014-01-01

OBJECTIVE: Hip fractures have been associated with increased mortality in the elderly. Several risk factors such as the time between the insult and the surgical repair have been associated with hip fracture mortality. Nevertheless, the risk of delayed surgical repair remains controversial. Few studies have examined this issue in Brazil. The aim of this study was to study the risk factors for death one year after hip fracture and in-hospital stay at a tertiary hospital in South Brazil. METHODS: A prospective cohort study was carried out from April 2005 to April 2011 at a tertiary university hospital at Santa Maria, Brazil. Subjects admitted for hip fracture who were 65 years of age or older were followed for one year. Information about fracture type, age, gender, clinical comorbidities, time to surgery, discharge, and American Society of Anesthesiologists score were recorded. Death was evaluated during the hospital stay and at one year. RESULTS: Four hundred and eighteen subjects were included in the final analysis. Of these, 4.3% died in-hospital and 15.3% were dead at one year. Time to surgery, American Society of Anesthesiologists score, Ischemic Heart Disease, and in-hospital stay were associated with death at one year in the univariate analysis. The American Society of Anesthesiologists score and time to surgery were one-year mortality predictors in the final regression model. In-hospital death was associated with American Society of Anesthesiologists score and age. CONCLUSION: Time to surgery is worryingly high at the South Brazil tertiary public health center studied here. Surgical delay is a risk factor that has the potential to be modified to improve mortality. PMID:24714833

Immediate percutaneous sacroiliac screw insertion for unstable pelvic fractures: is it safe enough?

PubMed

Acker, A; Perry, Z H; Blum, S; Shaked, G; Korngreen, A

2018-04-01

The purpose of this study was to compare the results of immediate and delayed percutaneous sacroiliac screws surgery for unstable pelvic fractures, regarding technical results and complication rate. Retrospective study. The study was conducted at the Soroka University Medical center, Beer Sheva, Israel, which is a level 1 trauma Center. 108 patients with unstable pelvic injuries were operated by the orthopedic department at the Soroka University Medical Center between the years 1999-2010. A retrospective analysis found 50 patients with immediate surgery and 58 patients with delayed surgery. Preoperative and postoperative imaging were analyzed and data was collected regarding complications. All patients were operated on by using the same technique-percutaneous fixation of sacroiliac joint with cannulated screws. The study's primary outcome measure was the safety and quality of the early operation in comparison with the late operation. A total of 156 sacroiliac screws were inserted. No differences were found between the immediate and delayed treatment groups regarding technical outcome measures (P value = 0.44) and complication rate (P value = 0.42). The current study demonstrated that immediate percutaneous sacroiliac screw insertion for unstable pelvic fractures produced equally good technical results, in comparison with the conventional delayed operation, without additional complications.

Predictors of Time to Union After Operative Fixation of Closed Ankle Fractures.

PubMed

Matson, Andrew P; Hamid, Kamran S; Adams, Samuel B

2017-08-01

Ankle fractures are common and represent a significant burden to society. We aim to report the rate of union as determined by clinical and radiographic data, and to identify factors that predict time to union. A cohort of 112 consecutive patients with isolated, closed, operative malleolar ankle fractures treated with open reduction and internal fixation was retrospectively reviewed for time to clinical union. Clinical union was defined based on radiographic and clinical parameters, and delayed union was defined by time to union >12 weeks. Injury characteristics, patient factors and treatment variables were recorded, and statistical techniques employed included the Chi-square test, the Student's T-test, and multivariate linear regression modeling. Forty-two (37.5%) of patients who achieved union did so in less than 12 weeks, and 69 (61.6%) of these patients demonstrated delayed union at a mean of 16.7 weeks (range, 12.1-26.7 weeks), and the remaining patient required revision surgery. Factors associated with higher rates of delayed union or increased time to union included tobacco use, bimalleolar fixation, and high energy mechanism (all p<0.05). In regression analysis, statistically significant negative predictors of time to union were BMI, dislocation of the tibiotalar joint, external fixation for initial stabilization and delay of definitive management (all p<0.05). Patient characteristics, injury factors and treatment variables are predictive of time to union following open reduction and internal fixation of closed ankle fractures. These findings should assist with patient counseling, and help guide the provider when considering adjunctive therapies that promote bone healing. Prognostic, Level IV: Case series.

The impact of social isolation on delayed hospital discharges of older hip fracture patients and associated costs.

PubMed

Landeiro, F; Leal, J; Gray, A M

2016-02-01

Delayed discharges represent an inefficient use of acute hospital beds. Social isolation and referral to a public-funded rehabilitation unit were significant predictors of delayed discharges while admission from an institution was a protective factor for older hip fracture patients. Preventing delays could save between 11.2 and 30.7 % of total hospital costs for this patient group. Delayed discharges of older patients from acute care hospitals are a major challenge for administrative, humanitarian, and economic reasons. At the same time, older people are particularly vulnerable to social isolation which has a detrimental effect on their health and well-being with cost implications for health and social care services. The purpose of the present study was to determine the impact and costs of social isolation on delayed hospital discharge. A prospective study of 278 consecutive patients aged 75 or older with hip fracture admitted, as an emergency, to the Orthopaedics Department of Hospital Universitário de Santa Maria, Portugal, was conducted. A logistic regression model was used to examine the impact of relevant covariates on delayed discharges, and a negative binomial regression model was used to examine the main drivers of days of delayed discharges. Costs of delayed discharges were estimated using unit costs from national databases. Mean age at admission was 85.5 years and mean length of stay was 13.1 days per patient. Sixty-two (22.3 %) patients had delayed discharges, resulting in 419 bed days lost (11.5 % of the total length of stay). Being isolated or at a high risk of social isolation, measured with the Lubben social network scale, was significantly associated with delayed discharges (odds ratio (OR) 3.5) as was being referred to a public-funded rehabilitation unit (OR 7.6). These two variables also increased the number of days of delayed discharges (2.6 and 4.9 extra days, respectively, holding all else constant). Patients who were admitted from an institution were less likely to have delayed discharges (OR 0.2) with 5.5 fewer days of delay. Total costs of delayed discharges were between 11.2 and 30.7 % of total costs (€2352 and €9317 per patient with delayed discharge) conditional on whether waiting costs for placement in public-funded rehabilitation unit were included. High risk of social isolation, social isolation and referral to public-funded rehabilitation units increase delays in patients' discharges from acute care hospitals.

Quantitative Survey and Structural Classification of Hydraulic Fracturing Chemicals Reported in Unconventional Gas Production.

PubMed

Elsner, Martin; Hoelzer, Kathrin

2016-04-05

Much interest is directed at the chemical structure of hydraulic fracturing (HF) additives in unconventional gas exploitation. To bridge the gap between existing alphabetical disclosures by function/CAS number and emerging scientific contributions on fate and toxicity, we review the structural properties which motivate HF applications, and which determine environmental fate and toxicity. Our quantitative overview relied on voluntary U.S. disclosures evaluated from the FracFocus registry by different sources and on a House of Representatives ("Waxman") list. Out of over 1000 reported substances, classification by chemistry yielded succinct subsets able to illustrate the rationale of their use, and physicochemical properties relevant for environmental fate, toxicity and chemical analysis. While many substances were nontoxic, frequent disclosures also included notorious groundwater contaminants like petroleum hydrocarbons (solvents), precursors of endocrine disruptors like nonylphenols (nonemulsifiers), toxic propargyl alcohol (corrosion inhibitor), tetramethylammonium (clay stabilizer), biocides or strong oxidants. Application of highly oxidizing chemicals, together with occasional disclosures of putative delayed acids and complexing agents (i.e., compounds designed to react in the subsurface) suggests that relevant transformation products may be formed. To adequately investigate such reactions, available information is not sufficient, but instead a full disclosure of HF additives is necessary.

Treatment of ankle fractures--our results.

PubMed

Vranic, Haris; Hadzimehmedagic, Amel; Gavrankapetanovic, Ismet; Zjakic, Amir; Talic, Adnana

2010-01-01

Break ankle today is becoming more frequent. There is a dilemma to operate immediately upon receipt or delayed surgical treatment for a day or two. This work aims at showing the importance of the anatomy, mechanism of injury, injury classification, diagnostic and therapeutic methods in treatment of brake ankle from our experience. In the past year in our clinic there were 30 patients treated for all types of ankle fractures, and these patients were divided in two groups. Patients of the first group are those immediately operated, and the second group were with delayed surgery. The results showed that the patients of the first group had better healing, fewer complications, better and faster rehabilitation. Second groups of patients were with complications in terms dehiscence of wounds, bad healing fracture and DVT. Our results showed that better result in the treatment of ankle fractures is achieved by aggressive treatment immediately after trauma, with reconstruction of articular surface and tibiofibular syndesmosis with early rehabilitation.

Assessment of malnutrition in hip fracture patients: effects on surgical delay, hospital stay and mortality.

PubMed

Symeonidis, Panagiotis D; Clark, David

2006-08-01

The importance of malnutrition in elderly hip fracture patients has long been recognised. All patients operated upon for a hip fracture over a five-year period were assessed according to two nutritional markers : a) serum albumin levels and b) peripheral blood total lymphocyte count. Patients were subdivided into groups according to the four possible combinations of these results. Outcomes according to four clinical outcome parameters were validated: a) waiting time to operation b) length of hospitalisation, c) in-hospital mortality, and d) one-year postoperative mortality. Significant differences were found between malnourished patients and those with normal laboratory values with regard to surgical delay and one year postoperative mortality. Malnourished patients were also more likely to be hospitalised longer than a month and to die during their hospital stay, but the difference was not significant. The combination of serum albumin level and total lymphocyte count can be used as an independent prognostic factor in hip fracture patients.

Rigid fixation of facial fractures in children.

PubMed

Koltai, P J; Rabkin, D; Hoehn, J

1995-01-01

This article presents a retrospective analysis of a selective use of rigid fixation among 62 children with facial fractures, treated at a Level I trauma center over a 5-year period (1986-1991). There were 21 mandible fractures, 11 orbital fractures, 11 zygomaticomalar complex fractures, 7 nasal fractures, 5 maxillary fractures, 3 pan-facial fractures, 2 nasal-orbital-ethmoidal complex fractures, and 2 frontal sinus fractures. Only 18 children had rigid fixation of their injuries. Complications of Le Fort upper facial fractures repaired with rigid fixation involved perioperative sinusitis; one case required oral antibiotics, the other ethmoidectomy and maxillary antrostomy. One child with a Le Fort fracture had delayed exposure of a zygomaticomalar buttress plate, which required surgical removal. Permanent enophthalmos occurred in two children with Le Fort fractures. The authors conclude that traditional conservative management is appropriate in most cases. However, in children aged 13 and older with mandible fractures and children with complex mid- and upper facial fractures, a judicious use of rigid fixation has advantages over the traditional techniques.

Benzo[a]pyrene impedes self-renewal and differentiation of mesenchymal stem cells and influences fracture healing.

PubMed

Zhou, Yiqing; Jiang, Rong; An, Liqin; Wang, Hong; Cheng, Sicheng; Qiong, Shi; Weng, Yaguang

2017-06-01

Mesenchymal stem cells (MSCs) are implicated in the bone-forming process during fracture repair. Benzo[a]pyrene (BaP)-a cigarette smoke component and powerful motivator of the aryl hydrocarbon receptor (Ahr)-unfavorably influences bone condition and osteoblast differentiation. The first thing we noticed decreases self-renewal and differentiation of human bone marrow mesenchymal stem (hBM-MSCs) from smokers and activates Ahr signaling in MSCs by up-regulating the Ahr target gene cytochrome P450 (CYP) 1B1 expression. In vitro studies, we employed C3H10T1/2 and bone marrow mesenchymal stem cells (BM-MSCs) with BaP and discovered that BaP impaired innate properties of MSCs. Further investigation into MSCs showed that exposure to BaP activated Ahr signaling and inhibited TGF-β1/SMAD4 and TGF-β1/ERK/AKT signaling pathways. Corresponding with the outcomes, tibial fracture calluses produced by BaP-administered rats appeared to delay healing. This effect of BaP was abrogated by resveratrol, a natural Ahr antagonist, in vitro and in vivo. These data demonstrated that Ahr may play a key role in BaP-impaired innate properties by inhibiting SMAD-dependent signaling pathways TGF-β1/SMAD4 and SMAD-independent TGF-β1/ERK/AKT signaling pathways. Furthermore, resveratrol inhibited MSCs from adverse effects caused by BaP. Copyright © 2017. Published by Elsevier B.V.

Ball-joint versus single monolateral external fixators for definitive treatment of tibial shaft fractures.

PubMed

Beltsios, Michail; Mavrogenis, Andreas F; Savvidou, Olga D; Karamanis, Eirineos; Kokkalis, Zinon T; Papagelopoulos, Panayiotis J

2014-07-01

To compare modular monolateral external fixators with single monolateral external fixators for the treatment of open and complex tibial shaft fractures, to determine the optimal construct for fracture union. A total of 223 tibial shaft fractures in 212 patients were treated with a monolateral external fixator from 2005 to 2011; 112 fractures were treated with a modular external fixator with ball-joints (group A), and 111 fractures were treated with a single external fixator without ball-joints (group B). The mean follow-up was 2.9 years. We retrospectively evaluated the operative time for fracture reduction with the external fixator, pain and range of motion of the knee and ankle joints, time to union, rate of malunion, reoperations and revisions of the external fixators, and complications. The time for fracture reduction was statistically higher in group B; the rate of union was statistically higher in group B; the rate of nonunion was statistically higher in group A; the mean time to union was statistically higher in group A; the rate of reoperations was statistically higher in group A; and the rate of revision of the external fixator was statistically higher in group A. Pain, range of motion of the knee and ankle joints, rates of delayed union, malunion and complications were similar. Although modular external fixators are associated with faster intraoperative fracture reduction with the external fixator, single external fixators are associated with significantly better rates of union and reoperations; the rates of delayed union, malunion and complications are similar.

[Minimally invasive percutaneous plate osteosynthesis versus open reduction and internal fixation for distal tibial fractures in adults: a meta-analysis].

PubMed

Zhang, Qing-xi; Gao, Fu-qiang; Sun, Wei; Wang, Yun-ting; Yang, Yu-run; Li, Zirong

2015-08-01

To perform a meta-analysis on clinical outcomes of minimally invasive percutaneous plate osteosynthesis (MIPPO) or open reduction and internal fixation (ORIF) for distal tibial fractures in adults. Pubmed database (from 1968 to March 2014), Cochrane library and CNKI database (from 1998 to March 2014) were searched. Case-control study on minimally invasive percutaneous plate osteosynthesis (MIPPO) or open reduction and internal fixation (ORIF) for distal tibial fractures in adults were chosen,and postoperative infection, operative time, blood loss, fracture nonunion rate, delayed union,fracture malunion rate were seen as evaluation index for meta analysis. The system review was performed using the method recommended by the Cochrane Collaboration. Totally 5 studies (366 patients) were enrolled. Meta-analysis showed that there were significant meaning in postoperative infection between MIPPO and ORIF [OR = 0.23,95% CI (0.06,0.92), P = 0.04]; fracture nonunion rate in MIPPO was lower than in ORIF group [OR = 0.16, 95% CI (0.03,0.76), P = 0.02]; operative time in MIPPO was shorter than in ORIF group, and had significant difference [MD = -14.42, 95% CI (-27.79, -1.05), P < 0.05]; blood loss in MIPPO was less than in ORIF group [MD= -87.17,95%CI (-99.20, -75.15), P < 0.05]; there was no obviously meaning in delayed union between two groups. For distal tibial fractures in adults, MIPPO has, advantages of short operative time, less blood loss, lower incidence of infection and fracture non-uniom, but with high fracture malunion rate. MIPPO for distal tibial fractures in adults is better than ORIF, and the best treatment should choose according to patient's condition.

Rheological Characteristics of Cement Grout and its Effect on Mechanical Properties of a Rock Fracture

NASA Astrophysics Data System (ADS)

Liu, Quansheng; Lei, Guangfeng; Peng, Xingxin; Lu, Chaobo; Wei, Lai

2018-02-01

Grouting reinforcement, which has an obvious strengthening effect on fractured rock mass, has been widely used in various fields in geotechnical engineering. The rheological properties of grout will greatly affect its diffusion radius in rock fractures, and the water-cement ratio is an important factor in determining the grouting flow patterns. The relationship between shear stress and shear rate which could reflect the grout rheological properties, the effects of water-cement ratio, and temperature on the rheological properties of grouting was studied in the laboratory. Besides, a new method for producing fractured rock specimens was proposed and solved the problem of producing natural fractured rock specimens. To investigate the influences of grouting on mechanical properties of a rock fracture, the fractured rock specimens made using the new method were reinforced by grouting on the independent designed grouting platform, and then normal and tangential mechanical tests were carried out on fractured rock specimens. The results showed that the mechanical properties of fractured rock mass are significantly improved by grouting, the peak shear strength and residual strength of rock fractures are greatly improved, and the resistance to deformation is enhanced after grouting. Normal forces affect the tangential behavior of the rock fracture, and the tangential stress strength increases with normal forces. The strength and stability of fractured rock mass are increased by grouting reinforcement.

Pelvic fracture urethral injury in males—mechanisms of injury, management options and outcomes

PubMed Central

Barratt, Rachel C.; Bernard, Jason; Mundy, Anthony R.

2018-01-01

Pelvic fracture urethral injury (PFUI) management in male adults and children is controversial. The jury is still out on the best way to manage these injuries in the short and long-term to minimise complications and optimise outcomes. There is also little in the urological literature about pelvic fractures themselves, their causes, grading systems, associated injuries and the mechanism of PFUI. A review of pelvic fracture and male PFUI literature since 1757 was performed to determine pelvic fracture classification, associated injuries and, PFUI classification and management. The outcomes of; suprapubic catheter (SPC) insertion alone, primary open surgical repair (POSR), delayed primary open surgical repair (DPOSR), primary open realignment (POR), primary endoscopic realignment (PER), delayed endoscopic treatment (DET) and delayed urethroplasty (DU) in male adults and children in all major series have been reviewed and collated for rates of restricture (RS), erectile dysfunction (ED) and urinary incontinence (UI). For SPC, POSR, DPOSR, POR, PER, DET and DU; (I) mean RS rate was 97.9%, 53.9%, 18%, 58.3%, 62.0%, 80.2%, 14.4%; (II) mean ED rate was 25.6%, 22.5%, 71%, 37.2%, 23.6%, 31.9%, 12.7%; (III) mean UI rate was 6.7%, 13.6%, 0%, 14.5%, 4.1%, 4.1%, 6.8%; (IV) mean FU in months was 46.3, 29.4, 12, 61, 31.4, 31.8, 54.9. For males with PFUI restricture and new onset ED is lowest following DU whilst UI is lowest following DPOSR. On balance DU offers the best overall outcomes and should be the treatment of choice for PFUI. PMID:29644168

Pelvic fracture urethral injury in males-mechanisms of injury, management options and outcomes.

PubMed

Barratt, Rachel C; Bernard, Jason; Mundy, Anthony R; Greenwell, Tamsin J

2018-03-01

Pelvic fracture urethral injury (PFUI) management in male adults and children is controversial. The jury is still out on the best way to manage these injuries in the short and long-term to minimise complications and optimise outcomes. There is also little in the urological literature about pelvic fractures themselves, their causes, grading systems, associated injuries and the mechanism of PFUI. A review of pelvic fracture and male PFUI literature since 1757 was performed to determine pelvic fracture classification, associated injuries and, PFUI classification and management. The outcomes of; suprapubic catheter (SPC) insertion alone, primary open surgical repair (POSR), delayed primary open surgical repair (DPOSR), primary open realignment (POR), primary endoscopic realignment (PER), delayed endoscopic treatment (DET) and delayed urethroplasty (DU) in male adults and children in all major series have been reviewed and collated for rates of restricture (RS), erectile dysfunction (ED) and urinary incontinence (UI). For SPC, POSR, DPOSR, POR, PER, DET and DU; (I) mean RS rate was 97.9%, 53.9%, 18%, 58.3%, 62.0%, 80.2%, 14.4%; (II) mean ED rate was 25.6%, 22.5%, 71%, 37.2%, 23.6%, 31.9%, 12.7%; (III) mean UI rate was 6.7%, 13.6%, 0%, 14.5%, 4.1%, 4.1%, 6.8%; (IV) mean FU in months was 46.3, 29.4, 12, 61, 31.4, 31.8, 54.9. For males with PFUI restricture and new onset ED is lowest following DU whilst UI is lowest following DPOSR. On balance DU offers the best overall outcomes and should be the treatment of choice for PFUI.

A rare combined injury of dorsal fracture-dislocation of four carpometacarpal joints and trapezium, trapezoid and distal radius bone fractures.

PubMed

Touloupakis, Georgios; Stuflesser, Wilfried; Antonini, Guido; Ferrara, Fabrizio; Crippa, Cornelio; Lettera, Maria Gabriella

2016-05-06

Incorrect or delayed diagnosis and treatment of the carpometacarpal fracture-dislocations is often associated with poor prognosis. We present a rare case of unusual pattern of injury, involving dorsal dislocation of four ulnar carpometacarpal joints, associated with fracture of the trapezium, a burst fracture of the trapezoid  bone and an extra-articular fracture of the third distal  of the radius. The first surgical intervention was followed by unsatisfactory results, confirmed by the CT scans. A second surgery followed and an open reduction and pinning with K wires performed. Post-operative follow up lasting for nine months revealed a very good surgical outcome.

Early Appropriate Care: A Protocol to Standardize Resuscitation Assessment and to Expedite Fracture Care Reduces Hospital Stay and Enhances Revenue.

PubMed

Vallier, Heather A; Dolenc, Andrea J; Moore, Timothy A

2016-06-01

We hypothesized that a standardized protocol for fracture care would enhance revenue by reducing complications and length of stay. Prospective consecutive series. Level 1 trauma center. Two hundread and fifty-three adult patients with a mean age of 40.7 years and mean Injury Severity Score of 26.0. Femur, pelvis, or spine fractures treated surgically. Hospital and professional charges and collections were analyzed. Fixation was defined as early (<36 hours) or delayed. Complications and hospital stay were recorded. Mean charges were US $180,145 with a mean of US $66,871 collected (37%). The revenue multiplier was US $59,882/$6989 (8.57), indicating hospital collection of US $8.57 for every professional dollar, less than half of which went to orthopaedic surgeons. Delayed fracture care was associated with more intensive care unit (4.5 vs. 9.4) and total hospital days (9.4 vs. 15.3), with mean loss of actual revenue US $6380/patient delayed (n = 47), because of the costs of longer length of stay. Complications were associated with the highest expenses: mean of US $291,846 charges and US $101,005 collections, with facility collections decreased by 5.1%. An uncomplicated course of care was associated with the most favorable total collections: (US $60,017/$158,454 = 38%) and the shortest mean stay (8.7 days). Facility collections were nearly 9 times more than professional collections. Delayed fixation was associated with more complications, and facility collections decreased 5% with a complication. Furthermore, delayed fixation was associated with longer hospital stay, accounting for US $300K more in actual costs during the study. A standardized protocol to expedite definitive fixation enhances the profitability of the trauma service line. Economic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Constructing an episode of care from acute hospitalization records for studying effects of timing of hip fracture surgery.

PubMed

Sheehan, Katie J; Sobolev, Boris; Guy, Pierre; Bohm, Eric; Hellsten, Erik; Sutherland, Jason M; Kuramoto, Lisa; Jaglal, Susan

2016-02-01

Episodes of care defined by the event of hip fracture surgery are widely used for the assessment of surgical wait times and outcomes. However, this approach does not consider nonoperative deaths, implying that survival time begins at the time of procedure. This approach makes treatment effect implicitly conditional on surviving to treatment. The purpose of this article is to describe a novel conceptual framework for constructing an episode of hip fracture care to fully evaluate the incidence of adverse events related to time after admission for hip fracture. This admission-based approach enables the assessment of the full harm of delay by including deaths while waiting for surgery, not just deaths after surgery. Some patients wait until their conditions are optimized for surgery, whereas others have to wait until surgical service becomes available. We provide definitions, linkage rules, and algorithms to capture all hip fracture patients and events other than surgery. Finally, we discuss data elements for stratifying patients according to administrative factors for delay to allow researchers and policymakers to determine who will benefit most from expedited access to surgery. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Pelvic-fracture urethral injury in children

PubMed Central

Hagedorn, Judith C.; Voelzke, Bryan B.

2015-01-01

Objective To review paediatric posterior urethral injuries and the current potential management options; because urethral injury due to pelvic fracture in children is rare and has a low incidence, the management of this type of trauma and its complications remains controversial. Methods We reviewed previous reports identified by searching the PubMed Medline electronic database for clinically relevant articles published in the past 25 years. The search was limited to the keywords ‘pediatric’, ‘pelvic fracture’, ‘urethral injury’, ‘stricture’, ‘trauma’ and ‘reconstruction’. Results Most paediatric urethral injuries are a result of pelvic fractures after high-impact blunt trauma. After the diagnosis, immediate bladder drainage via a suprapubic cystotomy, or urethral realignment, are the initial management options, except for a possible immediate primary repair in girls. The common complications of pelvic fracture-associated urethral injury include urethral stricture formation, incontinence and erectile dysfunction. Excellent results can be achieved with delayed urethroplasty for pelvic fracture-associated urethral injuries. Conclusion Traumatic injury to the paediatric urethra is rare and calls for an immediate diagnosis and management. These devastating injuries have a high complication rate and therefore a close follow-up is warranted to assure adequate delayed repair by a reconstructive urologist. PMID:26019977

Complications and their risk factors following hip fracture surgery.

PubMed

Poh, Keng Soon; Lingaraj, K

2013-08-01

PURPOSE. To evaluate various postoperative complications and their risk factors in hip fracture patients. METHODS. 207 female and 87 male consecutive patients (mean age, 78.1 years) who underwent surgical (n=242) or conservative (n=52) treatment for closed fractures of the femoral neck (n=157) or peritrochanter (n=137) were prospectively studied. The types of complication and outcome were recorded. The comorbidity status of the patients was categorised based on the American Society of Anesthesiologists (ASA) classification. Complications and their associations with various risk factors and mortality were analysed. RESULTS. For all patients, the mean length of hospitalisation was 14.6 days. For the 242 patients who underwent surgical treatment after a mean of 3.6 days, 56.8% of them had at least one complication. Acute urinary retention (39.3%) and urinary tract infection (24.0%) were most common. Patients with ASA grade III or higher had 2.3 fold higher risk of developing complications than those with lower-grade comorbidity, whereas patients with delayed operation (>48 hours after presentation) had 1.8 fold higher risk of developing complications than those without delayed operation. Four patients died in hospital: 2 from myocardial infarction and 2 from upper gastrointestinal bleeding. CONCLUSION. Complications after hip fracture surgery were common. Advanced age, high ASA status, and delay in surgery were associated with higher complication rates. Operations should be performed on medically fit patients as early as possible.

Does the Zone of Injury in Combat-Related Type III Open Tibia Fractures Preclude the Use of Local Soft Tissue Coverage?

DTIC Science & Technology

2010-11-01

delayed union , non- union , and deep infection.39 The large zone of injury surrounding the open fracture site led to the rationale that free flap coverage...also lower for the rotational flap cohort (7% versus 27%, P 0.08). The average time to fracture union for the free flap group was 9.5 months (range, 5...success of coverage, complication rates, visual pain scores, time to radiographic fracture union , and progression to amputation for local rotational

Composite Bone and Soft Tissue Loss Treated with Distraction Histiogenesis

DTIC Science & Technology

2010-01-01

their frames removed had healed docking sites, and the fourth whose frame remained in place had a healing fracture without evidence of delayed union ...interventions (3–8). The goals of limb salvage surgery in this setting are to restore length and alignment, regenerate bone loss, obtain fracture union ...angulation to manage composite bone and soft tissue loss associated with combat-related type IIIB open tibia fractures . Four patients underwent placement

Numerical Simulation of Permeability Change in Wellbore Cement Fractures after Geomechanical Stress and Geochemical Reactions Using X-ray Computed Tomography Imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kabilan, Senthil; Jung, Hun Bok; Kuprat, Andrew P.

X-ray microtomography (XMT) imaging combined with a three-dimensional (3D) computational fluid dynamics (CFD) modeling technique was used to study the effect of geochemical and geomechanical processes on fracture properties in composite Portland cement–basalt caprock core samples. The effect of fluid properties and flow conditions on fracture permeability was numerically studied by using fluids with varying physical properties and simulating different pressure conditions. CFD revealed that the application of geomechanical stress led to increased fluid flow, which resulted in increased fracture permeability. After CO2-reaction, XMT images displayed preferential precipitation of calcium carbonate within the fractures in the cement matrix and lessmore » precipitation in fractures located at the cement–basalt interface. CFD predicted changes in flow characteristics and differences in absolute values of flow properties due to different pressure gradients. CFD was able to highlight the profound effect of fluid properties on flow characteristics and hydraulic properties of fractures. This study demonstrates the applicability of XMT imaging and CFD as powerful tools for characterizing the hydraulic properties of fractures in a number of applications like geologic carbon sequestration and storage, hydraulic fracturing for shale gas production, and enhanced geothermal systems.« less

Damage Control Orthopedics Management as Vital Procedure in Elderly Patients with Femoral Neck Fractures Complicated with Chronic Renal Failure: A Retrospective Cohort Study

PubMed Central

Dong, Chenhui; Wang, Yunjiao; Wang, Ziming; Wang, Yu; Wu, Siyu; Du, Quanyin; Wang, Aimin

2016-01-01

Background Chronic renal failure (CRF) predisposes to hip fractures in elderly patients, with high subsequent mortality. Selection and timing of the surgical procedure of such patients is a serious challenge. Many clinicians believe in earlier surgery as preferable and providing better outcomes. Damage control orthopedics (DCO) aids to adjust and optimize the overall condition of patients. Methods In 32 patients with femoral neck fractures complicated with CRF, we evaluated how the timing of the surgery determines the mortality rates if the DCO approach is applied. Preoperative ASA grading, POSSUM score, P-POSSUM score and DCO were carried out. Based on the assessment, timing of the surgery was ascertained. Results Of a total of 32 patients, twenty-nine patients were accepted for either early (< 48 hours; n = 18) or delayed (3–10 days; n = 10) surgery. Hip arthroplasty (total hip arthroplasty and hemiarthroplasty) was the principal surgery option. All patients survived operation and were followed up postoperatively with the average time of 30 days. Postoperative complications tended to occur at higher rates in the early vs. delayed surgery group (7/18 vs. 5/10). During follow up, a total of 3 patients died in both groups (2/18 in the early surgery and 1/10 in the delayed surgery group), mostly from multi-organ failures and acute respiratory distress syndrome. There was no significant difference in complication rates and Harris hip score between both groups. Conclusion In patients with femoral neck fracture complicated with CRF, delaying the surgery for several days does not increase the incidence of postoperative adverse events. PMID:27149117

An Integrated Tensorial Approach for Quantifying Porous, Fractured Rocks

NASA Astrophysics Data System (ADS)

Healy, David; Rizzo, Roberto; Harland, Sophie; Farrell, Natalie; Browning, John; Meredith, Phil; Mitchell, Tom; Bubeck, Alodie; Walker, Richard

2017-04-01

The patterns of fractures in deformed rocks are rarely uniform or random. Fracture orientations, sizes, shapes and spatial distributions often exhibit some kind of order. In detail, there may be relationships among the different fracture attributes e.g. small fractures dominated by one orientation, and larger fractures by another. These relationships are important because the mechanical (e.g. strength, anisotropy) and transport (e.g. fluids, heat) properties of rock depend on these fracture patterns and fracture attributes. Based on previously published work (Oda, Cowin, Sayers & Kachanov) this presentation describes an integrated tensorial approach to quantifying fracture networks and predicting the key properties of fractured rock: permeability and elasticity (and in turn, seismic velocities). Each of these properties can be represented as tensors, and these entities capture the essential 'directionality', or anisotropy of the property. In structural geology, we are familiar with using tensors for stress and strain, where these concepts incorporate volume averaging of many forces (in the case of the stress tensor), or many displacements (for the strain tensor), to produce more tractable and more computationally efficient quantities. It is conceptually attractive to formulate both the structure (the fracture network) and the structure-dependent properties (permeability, elasticity) in a consistent way with tensors of 2nd and 4th rank, as appropriate. Examples are provided to highlight the interdependence of the property tensors with the geometry of the fracture network. The fabric tensor (or orientation tensor of Scheidegger, Woodcock) describes the orientation distribution of fractures in the network. The crack tensor combines the fabric tensor (orientation distribution) with information about the fracture density and fracture size distribution. Changes to the fracture network, manifested in the values of the fabric and crack tensors, translate into changes in predicted permeability and elasticity (seismic velocity). Conversely, this implies that measured changes in any of the in situ properties or responses in the subsurface (e.g. permeability, seismic velocity) could be used to predict, or at least constrain, the fracture network. Explicitly linking the fracture network geometry to the permeability and elasticity (seismic velocity) through a tensorial formulation provides an exciting and efficient alternative to existing approaches.

Stress fractures about the tibia, foot, and ankle.

PubMed

Shindle, Michael K; Endo, Yoshimi; Warren, Russell F; Lane, Joseph M; Helfet, David L; Schwartz, Elliott N; Ellis, Scott J

2012-03-01

In competitive athletes, stress fractures of the tibia, foot, and ankle are common and lead to considerable delay in return to play. Factors such as bone vascularity, training regimen, and equipment can increase the risk of stress fracture. Management is based on the fracture site. In some athletes, metabolic workup and medication are warranted. High-risk fractures, including those of the anterior tibial diaphysis, navicular, proximal fifth metatarsal, and medial malleolus, present management challenges and may require surgery, especially in high-level athletes who need to return to play quickly. Noninvasive treatment modalities such as pulsed ultrasound and extracorporeal shock wave therapy may have some benefit but require additional research.

Delayed signatures of underground nuclear explosions

PubMed Central

Carrigan, Charles R.; Sun, Yunwei; Hunter, Steven L.; Ruddle, David G.; Wagoner, Jeffrey L.; Myers, Katherine B. L.; Emer, Dudley F.; Drellack, Sigmund L.; Chipman, Veraun D.

2016-01-01

Radionuclide signals from underground nuclear explosions (UNEs) are strongly influenced by the surrounding hydrogeologic regime. One effect of containment is delay of detonation-produced radioxenon reaching the surface as well as lengthening of its period of detectability compared to uncontained explosions. Using a field-scale tracer experiment, we evaluate important transport properties of a former UNE site. We observe the character of signals at the surface due to the migration of gases from the post-detonation chimney under realistic transport conditions. Background radon signals are found to be highly responsive to cavity pressurization suggesting that large local radon anomalies may be an indicator of a clandestine UNE. Computer simulations, using transport properties obtained from the experiment, track radioxenon isotopes in the chimney and their migration to the surface. They show that the chimney surrounded by a fractured containment regime behaves as a leaky chemical reactor regarding its effect on isotopic evolution introducing a dependence on nuclear yield not previously considered. This evolutionary model for radioxenon isotopes is validated by atmospheric observations of radioxenon from a 2013 UNE in the Democratic People’s Republic of Korea (DPRK). Our model produces results similar to isotopic observations with nuclear yields being comparable to seismic estimates. PMID:26979288

Delayed signatures of underground nuclear explosions

NASA Astrophysics Data System (ADS)

Carrigan, Charles R.; Sun, Yunwei; Hunter, Steven L.; Ruddle, David G.; Wagoner, Jeffrey L.; Myers, Katherine B. L.; Emer, Dudley F.; Drellack, Sigmund L.; Chipman, Veraun D.

2016-03-01

Radionuclide signals from underground nuclear explosions (UNEs) are strongly influenced by the surrounding hydrogeologic regime. One effect of containment is delay of detonation-produced radioxenon reaching the surface as well as lengthening of its period of detectability compared to uncontained explosions. Using a field-scale tracer experiment, we evaluate important transport properties of a former UNE site. We observe the character of signals at the surface due to the migration of gases from the post-detonation chimney under realistic transport conditions. Background radon signals are found to be highly responsive to cavity pressurization suggesting that large local radon anomalies may be an indicator of a clandestine UNE. Computer simulations, using transport properties obtained from the experiment, track radioxenon isotopes in the chimney and their migration to the surface. They show that the chimney surrounded by a fractured containment regime behaves as a leaky chemical reactor regarding its effect on isotopic evolution introducing a dependence on nuclear yield not previously considered. This evolutionary model for radioxenon isotopes is validated by atmospheric observations of radioxenon from a 2013 UNE in the Democratic People’s Republic of Korea (DPRK). Our model produces results similar to isotopic observations with nuclear yields being comparable to seismic estimates.

Delayed signatures of underground nuclear explosions.

PubMed

Carrigan, Charles R; Sun, Yunwei; Hunter, Steven L; Ruddle, David G; Wagoner, Jeffrey L; Myers, Katherine B L; Emer, Dudley F; Drellack, Sigmund L; Chipman, Veraun D

2016-03-16

Radionuclide signals from underground nuclear explosions (UNEs) are strongly influenced by the surrounding hydrogeologic regime. One effect of containment is delay of detonation-produced radioxenon reaching the surface as well as lengthening of its period of detectability compared to uncontained explosions. Using a field-scale tracer experiment, we evaluate important transport properties of a former UNE site. We observe the character of signals at the surface due to the migration of gases from the post-detonation chimney under realistic transport conditions. Background radon signals are found to be highly responsive to cavity pressurization suggesting that large local radon anomalies may be an indicator of a clandestine UNE. Computer simulations, using transport properties obtained from the experiment, track radioxenon isotopes in the chimney and their migration to the surface. They show that the chimney surrounded by a fractured containment regime behaves as a leaky chemical reactor regarding its effect on isotopic evolution introducing a dependence on nuclear yield not previously considered. This evolutionary model for radioxenon isotopes is validated by atmospheric observations of radioxenon from a 2013 UNE in the Democratic People's Republic of Korea (DPRK). Our model produces results similar to isotopic observations with nuclear yields being comparable to seismic estimates.

Ideas, properties, and standards of fracture repositioning with osteopathy in traditional Mongolian medicine in China.

PubMed

Wang, Mei; Wang, Hongxia; Zhao, Namula

2015-02-01

To explore the unique ideas, properties, and standards of fracture repositioning with osteopathy in traditional Mongolian medicine in China. Based on the natural life concept of "integration of universe and man", osteopathy in traditional Mongolian medicine in China uses the modern principles and methods of physiology, psychology, and biomechanics. Against this background, we explored the unique ideas, properties, and stan- dards of fracture repositioning in traditional Mongolian medicine. Fracture treatment with osteopathy in traditional Mongolian medicine in China is based on (a) the ideas of natural, sealed, self and dynamic repositioning of fractures; (b) the properties of structural continuity and functional completeness; (c) the standards of "integration of movement and stillness" and "force to force". The unique ideas, properties, and standards of fracture repositioning with osteopathy in traditional Mongolian medicine in China have resulted in the widespread use of such techniques and represents the future direction of the development of fracture repositioning.

Application of oil-water discrimination technology in fractured reservoirs using the differences between fast and slow shear-waves

NASA Astrophysics Data System (ADS)

Luo, Cong; Li, Xiangyang; Huang, Guangtan

2017-08-01

Oil-water discrimination is of great significance in the design and adjustment of development projects in oil fields. For fractured reservoirs, based on anisotropic S-wave splitting information, it becomes possible to effectively solve such problems which are difficult to deal with in traditional longitudinal wave exploration, due to the similar bulk modulus and density of these two fluids. In this paper, by analyzing the anisotropic character of the Chapman model (2009 Geophysics 74 97-103), the velocity and reflection coefficient differences between the fast and slow S-wave caused by fluid substitution have been verified. Then, through a wave field response analysis of the theoretical model, we found that water saturation causes a longer time delay, a larger time delay gradient and a lower amplitude difference between the fast and slow S-wave, while the oil case corresponds to a lower time delay, a lower gradient and a higher amplitude difference. Therefore, a new class attribute has been proposed regarding the amplitude energy of the fast and slow shear wave, used for oil-water distinction. This new attribute, as well as that of the time delay gradient, were both applied to the 3D3C seismic data of carbonate fractured reservoirs in the Luojia area of the Shengli oil field in China. The results show that the predictions of the energy attributes are more consistent with the well information than the time delay gradient attribute, hence demonstrating the great advantages and potential of this new attribute in oil-water recognition.

Rehabilitation of neglected Monteggia fracture: Dislocations in children.

PubMed

Yıldırım, Azad; Nas, Kemal

2017-11-06

There are limited studies related to the rehabilitation of neglected Monteggia fracture-dislocations. This study reports the results of the rehabilitation of neglected Monteggia fractures and dislocations and the best treatment options available. Thirteen children were rehabilitated between 2009 and 2012. A retrospective chart review was conducted to record the following: age, gender, anatomic region of fractures, time delay from symptom onset to fracture, Bado classification, Mayo Elbow Performance Index (MEPI) which includes pain, range of motion and daily life comfort, surgeries, length of hospitalization, location and pattern of fracture, length of follow-up and complications. The study group included thirteen children and adolescents; eleven males and two females with a mean age of 8.5 (range 2-15) years. According to the Bado classification, 11 patients had type 1, one had type 3 and one had type 4 fracture-dislocations. For Mayo Elbow Performance Index (MEPI) scales, patients that were less than ten years old had greater mean scores. Two patients had superficial infection, one had subluxation, one had osteoarthritis, one had delayed bone union and two had rigidity at the elbow. The goals of elbow rehabilitation following Neglected Monteggia cases include restoring function by restoring motion and muscle performance; influencing scar remodeling and preventing joint contracture; and restoring or maintaining joint stability. Patients aged younger than 10 years and intervals of less than one-year, between trauma and diagnosis, as well as early and effective rehabilitation were found as important parameters regarding favorable outcomes.

Bone healing in 2016

PubMed Central

Buza, John A.; Einhorn, Thomas

2016-01-01

Summary Delayed fracture healing and nonunion occurs in up to 5–10% of all fractures, and can present a challenging clinical scenario for the treating physician. Methods for the enhancement of skeletal repair may benefit patients that are at risk of, or have experienced, delayed healing or nonunion. These methods can be categorized into either physical stimulation therapies or biological therapies. Physical stimulation therapies include electrical stimulation, low-intensity pulsed ultrasonography, or extracorporeal shock wave therapy. Biological therapies can be further classified into local or systemic therapy based on the method of delivery. Local methods include autologous bone marrow, autologous bone graft, fibroblast growth factor-2, platelet-rich plasma, platelet-derived growth factor, and bone morphogenetic proteins. Systemic therapies include parathyroid hormone and bisphosphonates. This article reviews the current applications and supporting evidence for the use of these therapies in the enhancement of fracture healing. PMID:27920804

Joint Distraction Treatments of Intra-Articular Fracture-Induced Posttraumatic Osteoarthritis in a Large Animal Model

DTIC Science & Technology

2017-10-01

that was developed this Year for use in the upcoming Aim 2 studies. 15. SUBJECT TERMS External Fixator, Fracture Fixation Delay, Yucatan Minipig 16... Yucatan minipig model of PTOA after IAF that was developed during our previous work (W81XWH-10-1-0864) to investigate the use of joint distraction to...proactive treatment for PTOA. 2. KEYWORDS Post-traumatic Osteoarthritis Intra-articular Fracture Yucatan Miniature Pig Impact Ankle Cartilage

Early Fixation of Calcaneus Fractures.

PubMed

Swords, Michael P; Penny, Phillip

2017-03-01

The treatment of calcaneus fractures is controversial. Historically, most operatively treated fractures have been approached with a lateral extensile incision requiring delay in operative treatment until swelling has improved. There is a current trend and interest in small incision approaches allowing, and in some cases requiring, earlier operative fixation. Clinical scenarios amenable to consideration for early fixation are reviewed. The sinus tarsi surgical approach and reduction techniques are outlined in detail. Copyright © 2016 Elsevier Inc. All rights reserved.

Lunate fractures and associated radiocarpal and midcarpal instabilities: a systematic review.

PubMed

Shunmugam, Meenalochani; Phadnis, Joideep; Watts, Amy; Bain, Gregory I

2018-01-01

The aim of this study was to analyse lunate fractures and any associated osseo-ligamentous injuries. A systematic review identified 34 cases. We identified carpal instabilities at the radiocarpal and midcarpal joints in volar and dorsal directions. Radiocarpal instabilities (10/34) were usually dorsoradial (8/10), with a transverse lunate fracture, best seen on a coronal image. Midcarpal instabilities (24/34) were usually volar (14/18), with a volar lunate shear fracture, best seen on a sagittal image. Instabilities were sub-classified into non-displaced, subluxated and dislocated. Associated fractures of the scaphoid and the radial and ulnar styloid processes were common. Lunate fractures without subluxation or dislocation had good outcomes with cast immobilization or fixation of associated fractures. Lunate fracture-subluxations are unstable injuries that are best managed with fixation of the carpal fractures. Lunate fracture-dislocations are complex injuries, requiring stabilization of the lunate, associated fractures and ligament injuries; complications are common and acute or delayed salvage procedures may be required.

Recurrent Proximal Femur Fractures in a Teenager With Osteogenesis Imperfecta on Continuous Bisphosphonate Therapy: Are We Overtreating?

PubMed

Vasanwala, Rashida F; Sanghrajka, Anish; Bishop, Nicholas J; Högler, Wolfgang

2016-07-01

Long-term bisphosphonate (BP) therapy in adults with osteoporosis is associated with atypical femoral fractures, caused by increased material bone density and prolonged suppression of bone remodeling which may reduce fracture toughness. In children with osteogenesis imperfecta (OI), long-term intravenous BP therapy improves bone structure and mass without further increasing the already hypermineralized bone matrix, and is generally regarded as safe. Here we report a teenage girl with OI type IV, who was started on cyclical intravenous pamidronate therapy at age 6 years because of recurrent fractures. Transiliac bone biopsy revealed classical structural features of OI but unusually low bone resorption surfaces. She made substantial improvements in functional ability, bone mass, and fracture rate. However, after 5 years of pamidronate therapy she started to develop recurrent, bilateral, nontraumatic, and proximal femur fractures, which satisfied the case definition for atypical femur fractures. Some fractures were preceded by periosteal reactions and prodromal pain. Pamidronate was discontinued after 7 years of therapy, following which she sustained two further nontraumatic femur fractures, and continued to show delayed tibial osteotomy healing. Despite rodding surgery, and very much in contrast to her affected, untreated, and normally mobile mother, she remains wheelchair-dependent. The case of this girl raises questions about the long-term safety of BP therapy in some children, in particular about the risk of oversuppressed bone remodeling with the potential for microcrack accumulation, delayed healing, and increased stiffness. The principal concern is whether there is point at which benefit from BP therapy could turn into harm, where fracture risk increases again. This case should stimulate debate whether current adult atypical femoral fracture guidance should apply to children, and whether low-frequency, low-dose cyclical, intermittent, or oral treatment maintenance regimens should be considered on a case-by-case basis. © 2016 American Society for Bone and Mineral Research. © 2016 American Society for Bone and Mineral Research.

Health Care Usage and Related Costs in Fibular Plating for AO Type 44-B Ankle Fractures in a Belgian University Hospital: An Exploratory Analysis.

PubMed

Smeets, Bart; Nijs, Stefaan; Nderlita, Meri; Vandoren, Cindy; Hoekstra, Harm

2016-01-01

Open reposition and internal fixation (ORIF) is the reference standard for unstable Arbeitsgemeinschaft für Osteosynthesefragen (AO)-type 44-B ankle fractures. Age, comorbidity, delayed-staged surgery, and length-of-stay (LOS) are all factors that presumably correlate positively with health care costs. We performed an exploratory analysis of the health care costs associated with the treatment of this type of fracture and hypothesized that these costs will be significantly greater for the elderly. A total of 217 patients with an acute AO type 44-B ankle fracture were included. We studied 14 variables, and 5 main cost categories were defined. The health care costs associated with the treatment of ankle fractures in the present study constituted more than one half (53%) of the hospitalization costs, which, in turn, were strongly related to the LOS. Delayed-staged surgery and age were the most important clinical variables driving the total health care costs and LOS (p < .001). The median LOS before ORIF was 6 times greater (12 versus 2 days) for patients treated using a delayed-staged surgery protocol. The cutoff age above which the costs differed significantly was 65 years. Thus, the median total health care costs for the treatment of these fractures were doubled in the older group ($9207 versus $4559), mainly owing to a 2 times greater LOS before ORIF (2 versus 4 days) and 3 times greater total LOS (4 versus 12.5 days) in the elderly. Surprisingly, the complication rate was equal (27.7% versus 29.3%) in the 2 groups. Therefore, to decrease the total health care costs, we should focus on a reduction of the costly LOS before ORIF in the elderly population. Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

A Prospective Randomized Study on Operative Treatment for Simple Distal Tibial Fractures-Minimally Invasive Plate Osteosynthesis Versus Minimal Open Reduction and Internal Fixation.

PubMed

Kim, Ji Wan; Kim, Hyun Uk; Oh, Chang-Wug; Kim, Joon-Woo; Park, Ki Chul

2018-01-01

To compare the radiologic and clinical results of minimally invasive plate osteosynthesis (MIPO) and minimal open reduction and internal fixation (ORIF) for simple distal tibial fractures. Randomized prospective study. Three level 1 trauma centers. Fifty-eight patients with simple and distal tibial fractures were randomized into a MIPO group (treatment with MIPO; n = 29) or a minimal group (treatment with minimal ORIF; n = 29). These numbers were designed to define the rate of soft tissue complication; therefore, validation of superiority in union time or determination of differences in rates of delayed union was limited in this study. Simple distal tibial fractures treated with MIPO or minimal ORIF. The clinical outcome measurements included operative time, radiation exposure time, and soft tissue complications. To evaluate a patient's function, the American Orthopedic Foot and Ankle Society ankle score (AOFAS) was used. Radiologic measurements included fracture alignment, delayed union, and union time. All patients acquired bone union without any secondary intervention. The mean union time was 17.4 weeks and 16.3 weeks in the MIPO and minimal groups, respectively. There was 1 case of delayed union and 1 case of superficial infection in each group. The radiation exposure time was shorter in the minimal group than in the MIPO group. Coronal angulation showed a difference between both groups. The American Orthopedic Foot and Ankle Society ankle scores were 86.0 and 86.7 in the MIPO and minimal groups, respectively. Minimal ORIF resulted in similar outcomes, with no increased rate of soft tissue problems compared to MIPO. Both MIPO and minimal ORIF have high union rates and good functional outcomes for simple distal tibial fractures. Minimal ORIF did not result in increased rates of infection and wound dehiscence. Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Osteoporotic fracture of the sacrum: sacroplasty and physical medecine.

PubMed

Thomas, E N; Cyteval, C; Herisson, C; Leonard, L; Blotman, F

2009-06-01

Traditional treatment of sacrum osteoporotic fractures is mainly based on antalgics and rest in bed. But complications are frequent, cutaneous, respiratory, thrombotic or digestive and mortality at 1 year significant. We wanted to define the interest of sacroplasty when treating osteoporotic fracture of sacrum. We reviewed literature while studying a clinical case in an elderly patient. Sacroplasty was efficient at short and mean delay to control the pain due to osteoporotic sacrum fracture. Rate of complications is low in the centers mastering the procedure. Sacroplasty is of evident interest for elderly patients suffering of an osteoporotic fracture of sacrum. It reduces decubitus complications, secondary effects of antalgics and allows an early reeducation.

Penile Fracture: A Meta-Analysis.

PubMed

Amer, Tarik; Wilson, Rebekah; Chlosta, Piotr; AlBuheissi, Salah; Qazi, Hasan; Fraser, Michael; Aboumarzouk, Omar M

2016-01-01

To review the causes and management of penile fracture and to compare between surgical and conservative management as well as immediate and delayed interventions in terms of overall and specific complications. A search of all reported literature was conducted for all articles reporting on the management and outcomes of penile fractures. Full texts of relevant articles were obtained and screened according to the inclusion criteria. Outcomes measures were numbers of patients receiving surgical or conservative management, aetiology of fracture, length of admission, complications as well as the specifics of diagnostic approaches and operative management. Data was collated and where possible meta-analysed using Revman software. A total of 58 relevant studies involving 3,213 patients demonstrated that intercourse accounts for only 48% of cases with masturbation and forced flexion accounting for 39%. Meta-analysis shows that surgical intervention was associated with significantly fewer complications vs. conservative management (p < 0.000001). Surgical intervention results in significantly less erectile dysfunction (ED), curvature and painful erection than conservative management. There was no significant difference in the number of patients developing plaques/nodules (p = 0.94). Meta-analysis shows that overall early surgery is preferable to delayed surgery but that rates of ED are not significantly different. Early surgical intervention is associated with significantly fewer complications than conservative management or delayed surgery. The combined outcome of rapid diagnosis by history and clinical examination and swift surgical intervention is key for reconstruction with minimal long-term complications. © 2016 S. Karger AG, Basel.

Intramedullary nailing versus plating for distal tibia fractures without articular involvement: a meta-analysis.

PubMed

Mao, Zhi; Wang, Guoqi; Zhang, Lihai; Zhang, Licheng; Chen, Shuo; Du, Hailong; Zhao, Yanpeng; Tang, Peifu

2015-06-16

The choice between intramedullary (IM) nailing or plating of distal tibia fractures without articular involvement remains controversial. A meta-analysis of randomized controlled trials (RCTs) and observational studies was performed to compare IM nailing with plating for distal tibia fractures without articular involvement and to determine the dominant strategy. The PubMed, Embase, Cochrane Library databases, Chinese Wan-Fang Database, and China National Knowledge Infrastructure were searched. Twenty-eight studies, which included 1863 fractures, met the eligible criteria. The meta-analysis did not identify a statistically significant difference between the two treatments in terms of the rate of deep infection, delayed union, removal of instrumentation, or secondary procedures either in the RCT or retrospective subgroups. IM nailing was associated with significantly more malunion events and a higher incidence of knee pain in the retrospective subgroup and across all the studies, but not significantly in the RCT subgroup, and a lower rate of delayed wound healing and superficial infection both in the RCT and retrospective subgroups relative to plating. A meta-analysis of the functional scores or questionnaires was not possible because of the considerable variation among the included studies, and no significant differences were observed. Evidence suggests that both IM nailing and plating are appropriate treatments as IM nailing shows lower rate of delayed wound healing and superficial infection and plating may avoid malunion and knee pain. These findings should be interpreted with caution, however, because of the heterogeneity of the study designs. Large, rigorous RCTs are required.

Fractures of the Talus: State of the Art.

PubMed

Vallier, Heather A

2015-09-01

Talus fractures occur rarely but are often associated with complications and functional limitations. Urgent reduction of associated dislocations is recommended with open reduction and internal fixation of displaced fractures when adjacent soft tissue injury permits. Delayed definitive fixation may reduce the risks of wound complications and infections. Restoration of articular and axial alignment is necessary to optimize ankle and hindfoot function. Despite this, posttraumatic arthrosis occurs frequently after talar neck and body fractures, especially with comminution of the talar body. Osteonecrosis is reported in up to half of talar neck fractures, although many of these injuries will revascularize without collapse of the talar dome. Initial fracture displacement and presence of open fractures increase the risk of osteonecrosis. Talar process fractures may be subtle and easily missed on plain radiographs. Advanced imaging will provide detail to facilitate treatment planning. Therapeutic Level V. See Instructions for Authors for a complete description of levels of evidence.

Foot fractures frequently misdiagnosed as ankle sprains.

PubMed

Judd, Daniel B; Kim, David H

2002-09-01

Most ankle injuries are straightforward ligamentous injuries. However, the clinical presentation of subtle fractures can be similar to that of ankle sprains, and these fractures are frequently missed on initial examination. Fractures of the talar dome may be medial or lateral, and they are usually the result of inversion injuries, although medial injuries may be atraumatic. Lateral talar process fractures are characterized by point tenderness over the lateral process. Posterior talar process fractures are often associated with tenderness to deep palpation anterior to the Achilles tendon over the posterolateral talus, and plantar flexion may exacerbate the pain. These fractures can often be managed nonsurgically with nonweight-bearing status and a short leg cast worn for approximately four weeks. Delays in treatment can result in long-term disability and surgery. Computed tomographic scans or magnetic resonance imaging may be required because these fractures are difficult to detect on plain films.

Surgical treatment for pilon fracture of the ankle-open reduction and internal fixation.

PubMed

Chen, Y W; Huang, P J; Hsu, C Y; Kuo, C H; Cheng, Y M; Lin, S Y; Chen, L H; Chiang, H C

1998-01-01

From 1991 to 1994, 39 ankles of 38 patients underwent surgical open reduction and internal fixation for pilon fractures. These patients included 29 males and 9 females with an average age of 38.6 y/o (range 28 y/o-58 y/o). The follow up and evaluation period averaged 31.7 months (range 22Ms-44Ms), during which time a standing x-ray for arthrosis grading and functional scale was used for clinical evaluation. Complications included 1 case of infection, 1 case of loss reduction, 2 cases of partial skin necrosis and 2 cases of delayed union. Post-traumatic arthritis occurred in 23 ankles (59%) but only 4 ankles of grade 4 arthrosis resulted in poor functional scale and the overall satisfactory rate was 82%. It was found that anatomic reduction, rigid fixation and early motion exercise are important to successful treatment of ankle fractures. Regarding pilon fracture, specifically the severity of fracture pattern and delay of reduction are important problems to overcome to ensure successful results. Therefore, adequate surgical approach for entire view of ankle joint, reduction and fixation of fibula, sufficient bone graft for articular support, intraoperative x-ray check and postoperative immobilization are essential for the achievement of better clinical results.

Fluid-driven fracture propagation in heterogeneous media: Probability distributions of fracture trajectories

NASA Astrophysics Data System (ADS)

Santillán, David; Mosquera, Juan-Carlos; Cueto-Felgueroso, Luis

2017-11-01

Hydraulic fracture trajectories in rocks and other materials are highly affected by spatial heterogeneity in their mechanical properties. Understanding the complexity and structure of fluid-driven fractures and their deviation from the predictions of homogenized theories is a practical problem in engineering and geoscience. We conduct a Monte Carlo simulation study to characterize the influence of heterogeneous mechanical properties on the trajectories of hydraulic fractures propagating in elastic media. We generate a large number of random fields of mechanical properties and simulate pressure-driven fracture propagation using a phase-field model. We model the mechanical response of the material as that of an elastic isotropic material with heterogeneous Young modulus and Griffith energy release rate, assuming that fractures propagate in the toughness-dominated regime. Our study shows that the variance and the spatial covariance of the mechanical properties are controlling factors in the tortuousness of the fracture paths. We characterize the deviation of fracture paths from the homogenous case statistically, and conclude that the maximum deviation grows linearly with the distance from the injection point. Additionally, fracture path deviations seem to be normally distributed, suggesting that fracture propagation in the toughness-dominated regime may be described as a random walk.

Fluid-driven fracture propagation in heterogeneous media: Probability distributions of fracture trajectories.

PubMed

Santillán, David; Mosquera, Juan-Carlos; Cueto-Felgueroso, Luis

2017-11-01

Hydraulic fracture trajectories in rocks and other materials are highly affected by spatial heterogeneity in their mechanical properties. Understanding the complexity and structure of fluid-driven fractures and their deviation from the predictions of homogenized theories is a practical problem in engineering and geoscience. We conduct a Monte Carlo simulation study to characterize the influence of heterogeneous mechanical properties on the trajectories of hydraulic fractures propagating in elastic media. We generate a large number of random fields of mechanical properties and simulate pressure-driven fracture propagation using a phase-field model. We model the mechanical response of the material as that of an elastic isotropic material with heterogeneous Young modulus and Griffith energy release rate, assuming that fractures propagate in the toughness-dominated regime. Our study shows that the variance and the spatial covariance of the mechanical properties are controlling factors in the tortuousness of the fracture paths. We characterize the deviation of fracture paths from the homogenous case statistically, and conclude that the maximum deviation grows linearly with the distance from the injection point. Additionally, fracture path deviations seem to be normally distributed, suggesting that fracture propagation in the toughness-dominated regime may be described as a random walk.

CSA-90 Promotes Bone Formation and Mitigates Methicillin-resistant Staphylococcus aureus Infection in a Rat Open Fracture Model.

PubMed

Mills, Rebecca; Cheng, Tegan L; Mikulec, Kathy; Peacock, Lauren; Isaacs, David; Genberg, Carl; Savage, Paul B; Little, David G; Schindeler, Aaron

2018-06-01

Infection of open fractures remains a significant cause of morbidity and mortality to patients worldwide. Early administration of prophylactic antibiotics is known to improve outcomes; however, increasing concern regarding antimicrobial resistance makes finding new compounds for use in such cases a pressing area for further research. CSA-90, a synthetic peptidomimetic compound, has previously demonstrated promising antimicrobial action against Staphylococcus aureus in rat open fractures. However, its efficacy against antibiotic-resistant microorganisms, its potential as a therapeutic agent in addition to its prophylactic effects, and its proosteogenic properties all require further investigation. (1) Does prophylactic treatment with CSA-90 reduce infection rates in a rat open fracture model inoculated with S aureus, methicillin-resistant S aureus (MRSA), and methicillin-resistant Staphylococcus epidermidis (MRSE) as measured by survival, radiographic union, and deep tissue swab cultures? (2) Does CSA-90 reduce infection rates when administered later in the management of an open fracture as measured by survival, radiographic union, and deep tissue swab cultures? (3) Does CSA-90 demonstrate a synergistic proosteogenic effect with bone morphogenetic protein 2 (BMP-2) in a noninfected rat ectopic bone formation assay as assessed by micro-CT bone volume measurement? (4) Can CSA-90 elute and retain its antimicrobial efficacy in vitro when delivered using clinically relevant agents measured using a Kirby-Bauer disc diffusion assay? All in vivo studies were approved by the local animal ethics committee. In the open fracture studies, 12-week-old male Wistar rats underwent open midshaft femoral fractures stabilized with a 1.1-mm Kirschner wire and 10 µg BMP-2 ± 500 µg CSA-90 was applied to the fracture site using a collagen sponge along with 1 x 10 colony-forming units of bacteria (S aureus/MRSA/MRSE; n = 10 per group). In the delayed treatment study, débridement and treatment with 500 µg CSA-90 were performed at Day 1 and Day 5 after injury and bacterial insult (S aureus). All animals were reviewed daily for signs of local infection and/or sepsis. An independent, blinded veterinarian reviewed twice-weekly radiographs, and rats showing osteolysis and/or declining overall health were culled at his instruction. The primary outcome of both fracture studies was fracture infection, incorporating survival, radiographic union, and deep tissue swab cultures. For the ectopic bone formation assay, 0 to 10 µg BMP-2 and 0 to 500 µg CSA-90 were delivered on a collagen sponge into bilateral quadriceps muscle pouches of 8-week-old rats (n = 10 per group). Micro-CT quantification of bone volume and descriptive histologic analysis were performed for all in vivo studies. Modified Kirby-Bauer disc diffusion assays were used to quantify antimicrobial activity in vitro using four different delivery methods, including bone cement. Infection was observed in none of the MRSA inoculated open fractures treated with CSA-90 with 10 of 10 deep tissue swab cultures negative at the time of cull. Median survival was 43 days (range, 11-43 days) in the treated group versus 11 days (range, 8-11 days) in the untreated MRSA inoculated group (p < 0.001). However, delayed débridement and treatment of open fractures with CSA-90 at either Day 1 or Day 5 did not prevent infection, resulting in early culls by Day 21 with positive swab cultures (10 of 10 for each time point). Maximal ectopic bone formation was achieved with 500 μg CSA-90 and 10 μg BMP-2 (mean volume, 9.58 mm; SD, 7.83), creating larger bone nodules than formed with 250 μg CSA-90 and 10 μg BMP-2 (mean volume, 1.7 mm; SD, 1.07; p < 0.001). Disc diffusion assays showed that CSA-90 could successfully elute from four potential delivery agents including calcium sulphate (mean zone of inhibition, 11.35 mm; SD, 0.957) and bone cement (mean, 4.67 mm; SD, 0.516). CSA-90 shows antimicrobial action against antibiotic-resistant Staphylococcal strains in vitro and in an in vivo model of open fracture infection. The antimicrobial properties of CSA-90 combined with further evidence of its proosteogenic potential make it a promising compound to develop further for orthopaedic applications.

Fracture of the penis--report of seven cases.

PubMed

Sharma, M Birkumar; Singh, Th Sudhirchandra; Khumukcham, Sridartha; Chito, Th; Sharma, B Bobby

2011-01-01

Fracture of the penis is an uncommon emergency consisting of rupture of the tunica albuginea of the corpus cavernosum resulting from blunt trauma over an erect penis. Prompt diagnosis and early surgical repair are essential to ensure a successful outcome with minimal complications. Delay may result in devastating physical and psychological disabilities that are potentially avoidable. Here in this article, 7 cases of fracture penis are being reported, who had been managed successfully by surgery in 6 cases and one case treated conservatively as he refused surgery.

Charcot joint-like changes following ankle fracture in a patient with no underlying disease: report of a rare case.

PubMed

Kumagai, Masaru; Yokota, Kiyoshi; Endoh, Toshiya; Takemoto, Hitoshi; Nagata, Kensei

2002-01-01

Charcot joint is a disease that often occurs in patients with diabetes mellitus, tabes dorsalis, syringomyelia, chronic alcoholism, leprosy, trauma, or infection after fractures and dislocations. The treatment for Charcot joint has various complications, such as skin lesions, infections, and delayed union. We present our experience with a male patient who developed Charcot joint-like changes without diabetes mellitus or any other disease after an ankle fracture due to minor trauma.

Elastic nailing of tibia shaft fractures in young children up to 10 years of age.

PubMed

Heo, Jeong; Oh, Chang-Wug; Park, Kyeong-Hyeon; Kim, Joon-Woo; Kim, Hee-June; Lee, Jong-Chul; Park, Il-Hyung

2016-04-01

Although tibia shaft fractures in children usually have satisfactory results after closed reduction and casting, there are several surgical indications, including associated fractures and soft tissue injuries such as open fractures. Titanium elastic nails (TENs) are often used for pediatric tibia fractures, and have the advantage of preserving the open physis. However, complications such as delayed union or nonunion are not uncommon in older children or open fractures. In the present study, we evaluated children up to 10 years of age with closed or open tibial shaft fractures treated with elastic nailing technique. A total of 16 tibia shaft fractures treated by elastic nailing from 2001 to 2013 were reviewed. The mean patient age at operation was 7 years (range: 5-10 years). Thirteen of 16 cases were open fractures (grade I: 4, grade II: 6, grade IIIA: 3 cases); the other cases had associated fractures that necessitated operative treatments. Closed, antegrade intramedullary nailing was used to insert two nails through the proximal tibial metaphysis. All patients were followed up for at least one year after the injury. Outcomes were evaluated using modified Flynn's criteria, including union, alignment, leg length discrepancies, and complications. All fractures achieved union a mean of 16.1 weeks after surgery (range: 11-26 weeks). No patient reported knee pain or experienced any loss of knee or ankle motion. There was a case of superficial infection in a patient with grade III open fracture. Three patients reported soft tissue discomfort due to prominent TEN tips at the proximal insertion site, which required cutting the tip before union or removing the nail after union. At the last follow-up, there were no angular or rotational deformities over 10° in either the sagittal or coronal planes. With the exception of one case with an overgrowth of 15 mm, no patient showed shortening or overgrowth exceeding 10mm. Among final outcomes, 15 were excellent and 1 was satisfactory. Even with open fractures or soft tissue injuries, elastic nailing can achieve satisfactory results in young children, with minimal complications of delayed bone healing, or infection. Copyright © 2015 Elsevier Ltd. All rights reserved.

Delaying Surgical Treatment of Penile Fracture Results in Poor Functional Outcomes: Results from a Large Retrospective Multicenter European Study.

PubMed

Bozzini, Giorgio; Albersen, Maarten; Otero, Javier Romero; Margreiter, Markus; Cruz, Eduard Garcia; Mueller, Alexander; Gratzke, Christian; Serefoglu, Ege Can; Salamanca, Juan Ignacio Martinez; Verze, Paolo

2018-01-01

Penile fracture is a rare clinical entity that represents a urologic emergency. It involves traumatic rupture of the tunica albuginea of the corpora cavernosa due to twisting or bending of the penile shaft during erection. To determine the differences in preoperative diagnostic evaluation patterns and outcomes of penile fracture patients to investigate the impact of surgical delay on functional outcomes. A retrospective analysis was performed using data obtained from 137 patients presenting with penile fracture at seven different European academic medical centers between 1996 and 2013. Age, imaging modalities used, timing of surgical intervention, length of tunica albuginea defect, and surgical technique were recorded. Postoperative erectile function outcomes were assessed with the International Index of Erectile Function (IIEF-5), and the presence of postoperative penile curvature was noted. The association between timing of surgical intervention and postoperative IIEF-5 results was evaluated with discriminant function analysis. The median age of the patients was 34.50 yr (interquartile range [IQR]: 28.0-46.5 yr). Of the 137 patients, 82 (59.85%) underwent penile Doppler ultrasound, and 5 patients (3.64%) were evaluated with magnetic resonance imaging. All patients were treated surgically, and the duration between emergency room admission and surgical intervention was 5.0h (IQR: 3.6-8.0h). The median length of tunica albuginea defect was 10mm (IQR: 8-20mm). Postoperative IIEF-5 scores were 21 (IQR: 12-23) and 23 (IQR: 15-24) at the first and third postoperative months, respectively. Discriminant function analysis revealed that if the surgical intervention was performed >8.23hours after emergency room admission, postoperative erectile function was significantly worse (p=0.0051 at first month and p=0.0057 at third month postoperatively). Our multicenter study showed that delaying surgical intervention results in significantly impaired erectile function. Surgical treatment must be planned as soon as possible to avoid postoperative erectile dysfunction. We looked at sexual outcomes following the repair of penile fracture in a large European population. We found that outcomes worsened if surgical repair was delayed. Copyright © 2016 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Femur Fractures in Professional Athletes: A Case Series

PubMed Central

Sikka, Robby; Fetzer, Gary; Hunkele, Thomas; Sugarman, Eric; Boyd, Joel

2015-01-01

Objective: To discuss return to play after femur fractures in several professional athletes. Background: Femur fractures are rare injuries and can be associated with significant morbidity and mortality. No reports exist, to our knowledge, on return to play after treatment of isolated femur fractures in professional athletes. Return to play is expected in patients with femur fractures, but recovery can take more than 1 year, with an expected decrease in performance. Treatment: Four professional athletes sustained isolated femur fractures during regular-season games. Two athletes played hockey, 1 played football, and 1 played baseball. Three players were treated with anterograde intramedullary nails, and 1 was treated with retrograde nailing. All players missed the remainder of the season. At an average of 9.5 months (range, 7–13 months) from the time of injury, all athletes were able to return to play. One player required the removal of painful hardware, which delayed his return to sport. Final radiographs revealed that all fractures were well healed. No athletes had subjective complaints or concerns that performance was affected by the injury at an average final follow-up of 25 months (range, 22–29 months). Uniqueness: As the size and speed of players increase, on-field trauma may result in significant injury. All players returned to previous levels of performance or exceeded previous statistical performance levels. Conclusions: In professional athletes, return to play from isolated femur fractures treated with either an anterograde or retrograde intramedullary nail is possible within 1 year. Return to the previous level of performance is possible, and it is important to develop management protocols, including rehabilitation guidelines, for such injuries. However, return to play may be delayed by subsequent procedures, including hardware removal. PMID:25680071

Anti-osteoporosis therapy and fracture healing.

PubMed

Larsson, Sune; Fazzalari, Nicola L

2014-02-01

A number of medications are approved for treatment of osteoporosis. As mode of action usually is anti-catabolic/anti-resorptive or anabolic, it is of interest to know whether these drugs affect not only normal bone remodeling, but also fracture healing. The purpose of this paper is to give a short overview of the potential effect of various anti-osteoporotic medication on fracture healing. A narrative literature review was performed to describe the current knowledge. Anti-catabolic/anti-resorptive drugs: for bisphosphonates, the most common class of drugs in this group, experimental studies have shown a larger and stronger callus and delayed remodeling but no evidence of delayed healing. A human monoclonal antibody to RANKL is another anti-catabolic drug, with the only report to date showing enhanced healing in an animal model. Strontium ranelate is a drug where both anti-catabolic and a weak anabolic effect have been proposed, with experimental data ranging from no effect to significant increase in both callus volume and strength. Anabolic drugs: PTH has demonstrated accelerated healing of various experimental fractures and of distal radius and pelvic fractures in humans. While the exact mechanism is not fully understood, PTH results in increased recruitment and differentiation of chondrocytes and enhancement of endochondral ossification. A monoclonal antibody to block sclerostin is another potential anabolic pathway, where animal data have shown increase in bone mass and strength. The potential effect on fracture healing is yet to be studied. There are still large gaps in the understanding of the potential effect of anti-osteoporotic drugs on fracture healing, although based on present knowledge a recent or present fracture should not be considered as a contraindication to such treatment.

Hybrid external fixation in the treatment of tibial pilon fractures: A retrospective analysis of 162 fractures.

PubMed

Galante, Vito N; Vicenti, Giovanni; Corina, Gianfranco; Mori, Claudio; Abate, Antonella; Picca, Girolamo; Conserva, Vito; Speciale, Domenico; Scialpi, Lorenzo; Tartaglia, Nicola; Caiaffa, Vincenzo; Moretti, Biagio

2016-10-01

To determine the efficacy of hybrid external fixation in the treatment of tibial pilon fractures. Retrospective, multicentre study. Adult patients with tibial pilon fractures treated with hybrid external fixation. Fracture reduction with ligamentotaxis and fixation with XCaliber hybrid external fixator. Fracture union, complications, functional outcome (Mazur Ankle Score). Union was obtained in 159 fractures at an average of 125days; there were three delayed unions and three non-unions. The most frequent complication was superficial pin-track infections (48), all of which responded to local wound care and antibiotics. There were no deep infections and no DVT. Only one fracture had loss of reduction that required frame revision. The overall functional scores were 91 (excellent) for AO/OTA type A fractures, 89 (good) for type B fractures, and 75 (satisfactory) for type C fractures. Hybrid external fixation is an effective method of stabilising tibial pilon fractures, particularly those with marked comminution. The minimally-invasive technique and stable fixation enable early mobilisation, with good functional results and minimal complications. Level IV Case series. Copyright © 2016 Elsevier Ltd. All rights reserved.

Treatment of femoral shaft fractures with monoaxial external fixation in polytrauma patients

PubMed Central

Testa, Gianluca; Aloj, Domenico; Ghirri, Alessandro; Petruccelli, Eraclite; Pavone, Vito; Massé, Alessandro

2017-01-01

Background: Femoral shaft fractures, typical in younger people, are often associated with polytrauma followed by traumatic shock. In these situations, despite intramedullary nailing being the treatment of choice, external fixation could be used as the definitive treatment. The aim of this study is to report evidence regarding definitive treatment of femoral shaft fractures with monoaxial external fixation. Methods: Between January 2006 and December 2015, 83 patients with 87 fractures were treated at the Department of Orthopaedics and Traumatology CTO of Turin, with a monoaxial external fixation device. Mean age at surgery, type of fracture, mean follow-up, time and modalities of treatment, non-weight bearing period, average healing, external fixation removal time, and complications were reported. Results: The average patient age was 31.43±15.19 years. In 37 cases (42.53%) the right femur was involved. 73 (83.91%) fractures were closed, and 14 (16.09%) were open. The average follow-up time was 61.07±21.86 weeks.  In 68 (78.16%) fractures the fixation was carried out in the first 24 hours, using a monoaxial external fixator. In the remaining 19 cases, the average delay was 6.80±4.54 days. Mean non-weight bearing time was 25.82±27.66 days (ranging from 0 to 120). The 87 fractures united at an average of 23.60±11.37 weeks (ranging from 13 to 102). The external fixator was removed after an average of 33.99±14.33 weeks (ranging from 20 to 120). Reported complications included 9.19% of delayed union, 1.15% of septic non-union, 5.75% of malunion, and 8.05% cases of loss of reduction. Conclusions: External fixation of femoral shaft fractures in polytrauma is an ideal method for definitive fracture stabilization, with minimal additional operative trauma and an acceptable complication rate. PMID:28928953

Effect of nano/micro B4C and SiC particles on fracture properties of aluminum 7075 particulate composites under chevron-notch plane strain fracture toughness test

NASA Astrophysics Data System (ADS)

Morovvati, M. R.; Lalehpour, A.; Esmaeilzare, A.

2016-12-01

Reinforcing aluminum with SiC and B4C nano/micro particles can lead to a more efficient material in terms of strength and light weight. The influence of adding these particles to an aluminum 7075 matrix is investigated using chevron-notch fracture toughness test method. The reinforcing factors are type, size (micro/nano), and weight percent of the particles. The fracture parameters are maximum load, notch opening displacement, the work up to fracture and chevron notch plane strain fracture toughness. The findings demonstrate that addition of micro and nano size particles improves the fracture properties; however, increasing the weight percent of the particles leads to increase of fracture properties up to a certain level and after that due to agglomeration of the particles, the improvement does not happen for both particle types and size categories. Agglomeration of particles at higher amounts of reinforcing particles results in improper distribution of particles and reduction in mechanical properties.

Experimental investigation of the hydraulic and heat-transfer properties of artificially fractured granite.

PubMed

Luo, Jin; Zhu, Yongqiang; Guo, Qinghai; Tan, Long; Zhuang, Yaqin; Liu, Mingliang; Zhang, Canhai; Xiang, Wei; Rohn, Joachim

2017-01-05

In this paper, the hydraulic and heat-transfer properties of two sets of artificially fractured granite samples are investigated. First, the morphological information is determined using 3D modelling technology. The area ratio is used to describe the roughness of the fracture surface. Second, the hydraulic properties of fractured granite are tested by exposing samples to different confining pressures and temperatures. The results show that the hydraulic properties of the fractures are affected mainly by the area ratio, with a larger area ratio producing a larger fracture aperture and higher hydraulic conductivity. Both the hydraulic apertureand the hydraulic conductivity decrease with an increase in the confining pressure. Furthermore, the fracture aperture decreases with increasing rock temperature, but the hydraulic conductivity increases owing to a reduction of the viscosity of the fluid flowing through. Finally, the heat-transfer efficiency of the samples under coupled hydro-thermal-mechanical conditions is analysed and discussed.

Experimental investigation of the hydraulic and heat-transfer properties of artificially fractured granite

PubMed Central

Luo, Jin; Zhu, Yongqiang; Guo, Qinghai; Tan, Long; Zhuang, Yaqin; Liu, Mingliang; Zhang, Canhai; Xiang, Wei; Rohn, Joachim

2017-01-01

In this paper, the hydraulic and heat-transfer properties of two sets of artificially fractured granite samples are investigated. First, the morphological information is determined using 3D modelling technology. The area ratio is used to describe the roughness of the fracture surface. Second, the hydraulic properties of fractured granite are tested by exposing samples to different confining pressures and temperatures. The results show that the hydraulic properties of the fractures are affected mainly by the area ratio, with a larger area ratio producing a larger fracture aperture and higher hydraulic conductivity. Both the hydraulic apertureand the hydraulic conductivity decrease with an increase in the confining pressure. Furthermore, the fracture aperture decreases with increasing rock temperature, but the hydraulic conductivity increases owing to a reduction of the viscosity of the fluid flowing through. Finally, the heat-transfer efficiency of the samples under coupled hydro-thermal-mechanical conditions is analysed and discussed. PMID:28054594

Impairment of wound healing after operative treatment of mandibular fractures, and the influence of dexamethasone.

PubMed

Snäll, Johanna; Kormi, Eeva; Lindqvist, Christian; Suominen, Anna Liisa; Mesimäki, Karri; Törnwall, Jyrki; Thorén, Hanna

2013-12-01

Our aim was to clarify the incidence of impaired wound healing after open reduction and ostheosynthesis of mandibular fractures, and to find out whether the use of dexamethasone during the operation increased the risk. Patients were drawn from a larger group of healthy adult dentate patients who had participated in a single-blind, randomised study, the aim of which was to clarify the benefits of operative dexamethasone after treatment of facial fractures. The present analysis comprised 41 patients who had had open reduction and fixation of mandibular fractures with titanium miniplates and monocortical screws through one or 2 intraoral approaches. The outcome variable was impaired healing of the wound. The primary predictive variable was the perioperative use of dexamethasone; other potential predictive variables were age, sex, smoking habit, type of fracture, delay in treatment, and duration of operation. Wound healing was impaired in 13/41 patients (32%) (13/53 of all fractures). The incidence among patients who were given dexamethasone and those who were not did not differ significantly. Only age over 25 was significantly associated with delayed healing (p=0.02). The use of dexamethasone 30 mg perioperatively did not significantly increase the risk of impaired wound healing in healthy patients with clinically uninfected mandibular fractures fixed with titanium miniplates through an intraoral approach. Older age is a significant predictor of impaired healing, which emphasises the importance of thorough anti-infective care in these patients during and after the operation. Copyright © 2013 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Recent biological trends in management of fracture non-union

PubMed Central

Emara, Khaled M; Diab, Ramy Ahmed; Emara, Ahmed Khaled

2015-01-01

Bone regeneration is a complex, well-orchestrated physiological process of bone formation, which can be seen during normal fracture healing, and is involved in continuous remodelling throughout adult life. Currently, there is a plethora of different strategies to augment the impaired or “insufficient” bone-regeneration process, including the “gold standard” autologous bone graft, free fibula vascularised graft, allograft implantation, and use of growth factors, osteoconductive scaffolds, osteoprogenitor cells and distraction osteogenesis. Improved “local” strategies in terms of tissue engineering and gene therapy, or even “systemic” enhancement of bone repair, are under intense investigation, in an effort to overcome the limitations of the current methods, to produce bone-graft substitutes with biomechanical properties that are as identical to normal bone as possible, to accelerate the overall regeneration process, or even to address systemic conditions, such as skeletal disorders and osteoporosis. An improved understanding of the molecular and cellular events that occur during bone repair and remodeling has led to the development of biologic agents that can augment the biological microenvironment and enhance bone repair. Orthobiologics, including stem cells, osteoinductive growth factors, osteoconductive matrices, and anabolic agents, are available clinically for accelerating fracture repair and treatment of compromised bone repair situations like delayed unions and nonunions. A lack of standardized outcome measures for comparison of biologic agents in clinical fracture repair trials, frequent off-label use, and a limited understanding of the biological activity of these agents at the bone repair site have limited their efficacy in clinical applications. PMID:26396938

Fatigue crack growth and fracture behavior of bainitic rail steels.

DOT National Transportation Integrated Search

2011-08-01

"The microstructuremechanical properties relationships, fracture toughness, fatigue crack growth and fracture surface morphology of J6 bainitic, manganese, and pearlitic rail steels were studied. Microstructuremechanical properties correlation ...

Fatigue crack growth and fracture behavior of bainitic rail steels.

DOT National Transportation Integrated Search

2011-09-01

"The microstructuremechanical properties relationships, fracture toughness, fatigue crack growth and fracture surface morphology of J6 bainitic, manganese, and pearlitic rail steels were studied. Microstructuremechanical properties correlation ...

Biomechanical assessment and clinical analysis of different intramedullary nailing systems for oblique fractures.

PubMed

Alierta, J A; Pérez, M A; Seral, B; García-Aznar, J M

2016-09-01

The aim of this study is to evaluate the fracture union or non-union for a specific patient that presented oblique fractures in tibia and fibula, using a mechanistic-based bone healing model. Normally, this kind of fractures can be treated through an intramedullary nail using two possible configurations that depends on the mechanical stabilisation: static and dynamic. Both cases are simulated under different fracture geometries in order to understand the effect of the mechanical stabilisation on the fracture healing outcome. The results of both simulations are in good agreement with previous clinical experience. From the results, it is demonstrated that the dynamization of the fracture improves healing in comparison with a static or rigid fixation of the fracture. This work shows the versatility and potential of a mechanistic-based bone healing model to predict the final outcome (union, non-union, delayed union) of realistic 3D fractures where even more than one bone is involved.

Complications in the Treatment of Adolescent Clavicle Fractures

PubMed Central

Luo, T. David; Ashraf, Ali; Larson, A. Noelle; Stans, Anthony A.; Shaughnessy, William J.; McIntosh, Amy L.

2015-01-01

The authors’ study evaluates the complications associated with the treatment of clavicle fractures in adolescents. During the study period, 153 clavicle fractures occurred in patients between the ages of 14 and 17 years who were treated at the authors’ center, of which 23 (15.0%) were treated surgically. Compared to the fractures treated nonoperatively, the surgical fractures had greater shortening (mean, 2.0 vs 0.9 cm; P<.001) and were more likely to be comminuted (65.2% vs 23.1%; P<.001). Complications occurred in 21.7% of fractures treated surgically. One delayed union occurred in the nonoperative cohort, but no other complications or patients who required clavicular osteotomy for malunion. Pediatric fellowship-trained orthopedic surgeons treated 78 displaced fractures, resulting in 8 (10.3%) surgeries. Nonpediatric orthopedic specialists treated 46 displaced fractures, 15 (32.6%) of which were treated operatively (P=.0035). FigureA 15-year-old boy sustained a comminuted clavicle fracture from playing football. Preoperative radiograph showing significant clavicle shortening and a vertical fragment. PMID:25901621

Mechanical properties and fracture behaviour of defective phosphorene nanotubes under uniaxial tension

NASA Astrophysics Data System (ADS)

Liu, Ping; Pei, Qing-Xiang; Huang, Wei; Zhang, Yong-Wei

2017-12-01

The easy formation of vacancy defects and the asymmetry in the two sublayers of phosphorene nanotubes (PNTs) may result in brand new mechanical properties and failure behaviour. Herein, we investigate the mechanical properties and fracture behaviour of defective PNTs under uniaxial tension using molecular dynamics simulations. Our simulation results show that atomic vacancies cause local stress concentration and thus significantly reduce the fracture strength and fracture strain of PNTs. More specifically, a 1% defect concentration is able to reduce the fracture strength and fracture strain by as much as 50% and 66%, respectively. Interestingly, the reduction in the mechanical properties is found to depend on the defect location: a defect located in the outer sublayer has a stronger effect than one located in the inner layer, especially for PNTs with a small diameter. Temperature is also found to strongly influence the mechanical properties of both defect-free and defective PNTs. When the temperature is increased from 0 K to 400 K, the fracture strength and fracture strain of defective PNTs with a defect concentration of 1% are reduced further by 71% and 61%, respectively. These findings are of great importance for the structural design of PNTs as building blocks in nanodevices.

Natural history of medial clavicle fractures.

PubMed

Salipas, Andrew; Kimmel, Lara A; Edwards, Elton R; Rakhra, Sandeep; Moaveni, Afshin Kamali

2016-10-01

Fractures of the medial third of the clavicle comprise less than 3% of all clavicle fractures. The natural history and optimal management of these rare injuries are unknown. The aim of our study is to describe the demographics, management and outcomes of patients with medial clavicle fractures treated at a Level 1 Trauma Centre. A retrospective review was conducted of patients presenting to our institution between January 2008 and March 2013 with a medial third clavicle fracture. Clinical and radiographic data were recorded including mechanism of injury, fracture pattern and displacement, associated injuries, management and complications. Functional outcomes were assessed using the Glasgow Outcome Scale Extended (GOS-E) scores from the Victorian Orthopaedic Trauma Outcomes Registry (VOTOR). Shoulder outcomes were assessed using two patient reported outcomes scores, the American Shoulder and Elbow Society Score (ASES) and the Subjective Shoulder Value (SSV). Sixty eight medial clavicle fractures in 68 patients were evaluated. The majority of patients were male (n=53), with a median age of 53.5 years (interquartile range (IQR) 37.5-74.5 years). The most common mechanism of injury was motor vehicle accident (n=28). The in-hospital mortality rate was 4.4%. The fracture pattern was almost equally distributed between extra articular (n=35) and intra-articular (n=33). Fifty-five fractures (80.9%) had minimal or no displacement. Associated injuries were predominantly thoracic (n=31). All fractures were initially managed non-operatively, with a broad arm sling. Delayed operative fixation was performed for painful atrophic delayed union in two patients (2.9%). Both patients were under 65 years of age and had a severely displaced fracture of the medial clavicle. One intra-operative vascular complication was seen, with no adverse long-term outcome. Follow-up was obtained in 85.0% of the surviving cohort at an average of three years post injury (range 1-6 years). The mean ASES score was 80.3 (SD 24.8, range 10-100,), and the mean SSV score was 77.0 (SD 24.6, range 10-100). Sixty eight patients with medial clavicle fractures were identified over a 5year period, with excellent functional results seen following conservative management. Copyright © 2016 Elsevier Ltd. All rights reserved.

Stability of highwalls in surface coal mines, western Powder Ridge Basin, Wyoming and Montana

USGS Publications Warehouse

Lee, Fitzhugh T.; Smith, William K.; Savage, William Z.

1976-01-01

Preliminary results from the first part of a two-part investigation of the stability of highwalls in open-pit coal mines in the Fort Union Formation of the western Powder River Basin of Wyoming and Montana indicate that these highwalls are subject to time-dependent deformation. Field investigations and laboratory physical-properties tests of coal and overburden rocks suggest that several factors influence highwall stability. Some of these factors are rebound of overconsolidated rocks, desiccation, water, orientation and spacing of fractures, and strength and deformation properties. Factors of safety for a typical highwall in the study area (calculated by the finite-element method) may be less than 1.0 when open fractures are present and the highwall has degraded. Although it is concluded that most open-pit mines in the Fort Union Formation within the study area have generally stable highwalls, these highwalls do deteriorate and become progressively less stable. Because of this, postmining failures are common and could be critical if mining were delayed and then resumed after a period of several months. The second part of the investigation will utilize field measurements of rock-mass properties and instrumentation of actively mined highwalls to obtain data for comparison with the results of the initial investigation. Because the height of highwalls will increase as the more shallow coal is exhausted, these data will also be used to predict the behavior of slopes higher than those presently found in the western Powder River Basin.

Comparative Evaluation of Enalapril and Losartan in Pharmacological Correction of Experimental Osteoporosis and Fractures of Its Background

PubMed Central

Rajkumar, D. S. R.; Faitelson, A. V.; Gudyrev, O. S.; Dubrovin, G. M.; Pokrovski, M. V.; Ivanov, A. V.

2013-01-01

In the experiment on the white Wistar female rats (222 animals), the osteoprotective effect of enalapril and losartan was studied on experimental models of osteoporosis and osteoporotic fractures. It was revealed that in rats after ovariectomy, the endothelial dysfunction of microcirculation vessels of osteal tissue develops, resulting in occurrence of osteoporosis and delay of consolidation of experimental fractures. Enalapril and losartan prevented the reduction of microcirculation in bone, which was reflected in slowing the thinning of bone trabeculae and in preventing the occurrence of these microfractures, as well as increasing quality of experimental fractures healing. PMID:23401845

Stress Fractures of the Foot.

PubMed

Hossain, Munier; Clutton, Juliet; Ridgewell, Mark; Lyons, Kathleen; Perera, Anthony

2015-10-01

Stress fractures of the foot and ankle may be more common among athletes than previously reported. A low threshold for investigation is warranted and further imaging may be appropriate if initial radiographs remain inconclusive. Most of these fractures can be treated conservatively with a period of non-weight-bearing mobilization followed by gradual return to activity. Early surgery augmented by bone graft may allow athletes to return to sports earlier. Risk of delayed union, nonunion, and recurrent fracture is high. Many of the patients may also have risk factors for injury that should be modified for a successful outcome. Copyright © 2015 Elsevier Inc. All rights reserved.

Multiple roles of tumor necrosis factor-alpha in fracture healing.

PubMed

Karnes, Jonathan M; Daffner, Scott D; Watkins, Colleen M

2015-09-01

This review presents a summary of basic science evidence examining the influence of tumor necrosis factor-alpha (TNF-α) on secondary fracture healing. Multiple studies suggest that TNF-α, in combination with the host reservoir of peri-fracture mesenchymal stem cells, is a main determinant in the success of bone healing. Disease states associated with poor bone healing commonly have inappropriate TNF-α responses, which likely contributes to the higher incidence of delayed and nonunions in these patient populations. Appreciation of TNF-α in fracture healing may lead to new therapies to augment recovery and reduce the incidence of complications. Copyright © 2015 Elsevier Inc. All rights reserved.

Intrinsic material property differences in bone tissue from patients suffering low-trauma osteoporotic fractures, compared to matched non-fracturing women.

PubMed

Vennin, S; Desyatova, A; Turner, J A; Watson, P A; Lappe, J M; Recker, R R; Akhter, M P

2017-04-01

Osteoporotic (low-trauma) fractures are a significant public health problem. Over 50% of women over 50yrs. of age will suffer an osteoporotic fracture in their remaining lifetimes. While current therapies reduce skeletal fracture risk by maintaining or increasing bone density, additional information is needed that includes the intrinsic material strength properties of bone tissue to help develop better treatments, since measurements of bone density account for no more than ~50% of fracture risk. The hypothesis tested here is that postmenopausal women who have sustained osteoporotic fractures have reduced bone quality, as indicated with measures of intrinsic material properties compared to those who have not fractured. Transiliac biopsies (N=120) were collected from fracturing (N=60, Cases) and non-fracturing postmenopausal women (N=60, age- and BMD-matched Controls) to measure intrinsic material properties using the nano-indentation technique. Each biopsy specimen was embedded in epoxy resin and then ground, polished and used for the nano-indentation testing. After calibration, multiple indentations were made using quasi-static (hardness, modulus) and dynamic (storage and loss moduli) testing protocols. Multiple indentations allowed the median and variance to be computed for each type of measurement for each specimen. Cases were found to have significantly lower median values for cortical hardness and indentation modulus. In addition, cases showed significantly less within-specimen variability in cortical modulus, cortical hardness, cortical storage modulus and trabecular hardness, and more within-specimen variability in trabecular loss modulus. Multivariate modeling indicated the presence of significant independent mechanical effects of cortical loss modulus, along with variability of cortical storage modulus, cortical loss modulus, and trabecular hardness. These results suggest mechanical heterogeneity of bone tissue may contribute to fracture resistance. Although the magnitudes of differences in the intrinsic properties were not overwhelming, this is the first comprehensive study to investigate, and compare the intrinsic properties of bone tissue in fracturing and non-fracturing postmenopausal women. Copyright © 2017 Elsevier Inc. All rights reserved.

Neglected nonunion of phalangeal neck fractures of the thumb in children: the outcome of delayed bone grafting in adulthood.

PubMed

Al-Qattan, Mohammad M

2012-03-01

Over a 12-year period, the author treated a total of 5 adults (mean age, 23 years) with neglected nonunion of phalangeal neck fractures of the thumb that were sustained in early childhood. Cosmetically, the affected thumb was shorter and smaller than the contralateral thumb. The thumb tip was flail and thumb pinch was weak. X-rays showed a nonunited phalangeal neck fracture with no radiologic evidence of avascular necrosis of the phalangeal head. All patients underwent iliac crest bone grafting. Bone union was obtained in all patients. At final follow-up (mean, 9 months), all patients were satisfied with the cosmetic appearance of the thumb. The thumb length increased by an average of 6 mm (range, 5-8 mm). Pinch improved in the range of 69% to 87% of the power of the contralateral thumb. However, there was restricted range of motion of the interphalangeal joint (mean range of motion of 10 degree only). It was concluded that delayed bone grafting of neglected nonunions of pediatric phalangeal neck fractures of the thumb is a worthwhile procedure and has a high satisfaction rate.

WISDOM GPR performance assessment in a cold artificial environment

NASA Astrophysics Data System (ADS)

Dechambre, M.; Ciarletti, V.; Biancheri-Astier, M.; Saintenoy, A.; Costard, F.; Hassen-Khodja, R.

2012-04-01

The WISDOM (Water Ice Subsurface Deposit Observation on Mars) GPR is one of the instruments that have been selected as part of the Pasteur payload of ESA's 2018 ExoMars Rover mission. WISDOM has been designed to obtain information about the nature of the subsurface along the rover path with the objective to explore the first ~ 3 m of the soil with a vertical resolution of a few centimetres. The sub-surface properties that can be addressed with WISDOM are variations in composition, texture, stratification (e.g., number, thickness and orientation of layers), the presence of unconformities and other structural characteristics (such as fractures and the deformation of strata). It is then essential to quantify the performances of WISDOM in controlled conditions, and several full polarimetric measurements have been carried out with the prototype in a cold artificial environment. The main objectives are the detection of different interface between homogeneous materials with WISDOM. The characterization of the material (porosity, % of water, dielectric properties, thickness and depth, temperature ...) is well-controlled. The cold room facility of IDES at Orsay (France) has been used, the ambient temperature ranged from -7° C to -10° C. A tank laying on the metallic floor (height: 0.5m, width: 0.80 m, length: 1.20m) in macrolon can contain liquid or frozen water or layers (dielectric contrasts) of home-maid permafrost (frozen saturated sand) with and without embedded objects or fractures. The temperature inside the medium (ice or permafrost) is controlled, the radar antennas are put on a sheet of polystyrene over the tank. Frequent measurements were performed (every 2cm) along a track from one side to the other side of the tank. The experimental conditions were: (1)dry cold sand (Fontainebleau sand) : porosity 35% density 2,67 (2) saturated wet sand : 35% of water (3) permafrost (frozen saturated sand) : 35% of ice content 1 layer: 3 consecutive experiments : 10cm dry sand ( 1) 10cm saturated sand (2) 10cm permafrost(3) 2 layers :previous 10cm permafrost in the bottom +3 consecutive experiments : 10cm dry sand ( 1) 10cm saturated sand (2) 10cm permafrost(3) . Basalt rocks and air fractures are or are not embedded in the layers Values of the permittivity of dry sand and permafrost were retrieve by two different ways. 1.Retrieval of the sand and permafrost permittivity from delay measurements knowing the layer thickness d ɛr = ct/2d = n2 2. Retrieval of the sand and permafrost permittivity from amplitude measurements knowing a calibration reference (reflection over a metallic plate), R is the Fresnel coefficient between the air and the medium. Aint/ = R = n- 1-,ɛ = 1+-R-= n2 Aair n +1 r 1- R Results : Internal layering is observed. The transition between dry sand and permafrost can be detected. The permittivity can be retrieved from delay or amplitude measurements as well from delay measurements : dry sand ɛr = 2.71 permafrost ɛr = 3.72 from amplitude measurements : dry sand ɛr = 2.73 permafrost ɛr = 3.35 Embedded objects are detected, Fracture and its orientation is detected.

A primer on selecting grain boundary sets for comparison of interfacial fracture properties in molecular dynamics simulations

DOE PAGES

Dingreville, Remi; Aksoy, Doruk; Spearot, Douglas E.

2017-08-21

In this study, all grain boundaries are not equal in their predisposition for fracture due to the complex coupling between lattice geometry, interfacial structure, and mechanical properties. The ability to understand these relationships is crucial to engineer materials resilient to grain boundary fracture. Here, a methodology is presented to isolate the role of grain boundary structure on interfacial fracture properties, such as the tensile strength and work of separation, using atomistic simulations. Instead of constructing sets of grain boundary models within the misorientation/structure space by simply varying the misorientation angle around a fixed misorientation axis, the proposed method creates setsmore » of grain boundary models by means of isocurves associated with important fracture-related properties of the adjoining lattices. Such properties may include anisotropic elastic moduli, the Schmid factor for primary slip, and the propensity for simultaneous slip on multiple slip systems. This approach eliminates the effect of lattice properties from the comparative analysis of interfacial fracture properties and thus enables the identification of structure-property relationships for grain boundaries. As an example, this methodology is implemented to study crack propagation along Ni grain boundaries. Segregated H is used as a means to emphasize differences in the selected grain boundary structures while keeping lattice properties fixed.« less

A primer on selecting grain boundary sets for comparison of interfacial fracture properties in molecular dynamics simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dingreville, Remi; Aksoy, Doruk; Spearot, Douglas E.

In this study, all grain boundaries are not equal in their predisposition for fracture due to the complex coupling between lattice geometry, interfacial structure, and mechanical properties. The ability to understand these relationships is crucial to engineer materials resilient to grain boundary fracture. Here, a methodology is presented to isolate the role of grain boundary structure on interfacial fracture properties, such as the tensile strength and work of separation, using atomistic simulations. Instead of constructing sets of grain boundary models within the misorientation/structure space by simply varying the misorientation angle around a fixed misorientation axis, the proposed method creates setsmore » of grain boundary models by means of isocurves associated with important fracture-related properties of the adjoining lattices. Such properties may include anisotropic elastic moduli, the Schmid factor for primary slip, and the propensity for simultaneous slip on multiple slip systems. This approach eliminates the effect of lattice properties from the comparative analysis of interfacial fracture properties and thus enables the identification of structure-property relationships for grain boundaries. As an example, this methodology is implemented to study crack propagation along Ni grain boundaries. Segregated H is used as a means to emphasize differences in the selected grain boundary structures while keeping lattice properties fixed.« less

Rap system of stress stimulation can promote bone union after lower tibial bone fracture: a clinical research.

PubMed

Yao, Jian-fei; Shen, Jia-zuo; Li, Da-kun; Lin, Da-sheng; Li, Lin; Li, Qiang; Qi, Peng; Lian, Ke-jian; Ding, Zhen-qi

2012-01-01

Lower tibial bone fracture may easily cause bone delayed union or nonunion because of lacking of dynamic mechanical load. Research Group would design a new instrument as Rap System of Stress Stimulation (RSSS) to provide dynamic mechanical load which would promote lower tibial bone union postoperatively. This clinical research was conducted from January 2008 to December 2010, 92 patients(male 61/female 31, age 16-70 years, mean 36.3 years) who suffered lower tibial bone closed fracture were given intramedullary nail fixation and randomly averagely separated into experimental group and control group(according to the successively order when patients went for the admission procedure). Then researchers analysed the clinical healing time, full weight bearing time, VAS (Visual Analogue Scales) score and callus growth score of Lane-Sandhu in 3,6,12 months postoperatively. The delayed union and nonunion rates were compared at 6 and 12 months separately. All the 92 patients had been followed up (mean 14 months). Clinical bone healing time in experimental group was 88.78±8.80 days but control group was 107.91±9.03 days. Full weight bearing time in experimental group was 94.07±9.81 days but control group was 113.24±13.37 days respectively (P<0.05). The delayed union rate in 6 months was 4.3% in experimental group but 10.9% in control group(P<0.05). The nonunion rate in 12 months was 6.5% in experimental group but 19.6% in control group(P<0.05). In 3, 6, 12 months postoperatively, VAS score and Lane-Sandhu score in experimental group had more significantly difference than them in control group. RSSS can intermittently provide dynamic mechanical load and stimulate callus formation, promote lower tibial bone union, reduce bone delayed union or nonunion rate. It is an adjuvant therapy for promoting bone union after lower tibial bone fracture.

Open fractures caused by high velocity missiles: the outcome of treatment of 39 fractures followed for 1-3 years.

PubMed

Khan, M A; Hussain, R; Khan, S H; Umar, M

1997-11-01

Between 1993 and 1995, thirty-three patients having 39 fractures caused by missiles fired from a high velocity rifle were reviewed retrospectively between 1 and 3 years after injury and the outcome of treatment assessed. Majority (33 out of 39) were Grade III. Union was achieved in 35 out of 39 fractures, there was deep infection and delayed union in one case each. Non-union occurred in three fractures. The fractures were stabilized using different techniques, but highest complication rate was seen with the use of the static external fixator. This was related to the severe nature of the injury as well as the inherent limitations of the external fixator. Revision of the external fixator with internal fixation after healing of the soft tissues seems to be the direction of the future.

Stress fractures of the foot and ankle.

PubMed

Welck, M J; Hayes, T; Pastides, P; Khan, W; Rudge, B

2017-08-01

Stress fractures occur as a result of microscopic injuries sustained when bone is subjected to repeated submaximal stresses. Overtime, with repeated cycles of loading, accumulation of such injuries can lead to macro-structural failure and frank fracture. There are numerous stress fractures about the foot and ankle of which a trauma and orthopaedic surgeon should be aware. These include: metatarsal, tibia, calcaneus, navicular, fibula, talus, medial malleolus, sesamoid, cuneiform and cuboid. Awareness of these fractures is important as the diagnosis is frequently missed and appropriate treatment delayed. Late identification can be associated with protracted pain and disability, and may predispose to non-union and therefore necessitate operative intervention. This article outlines the epidemiology and risk factors, aetiology, presentation and management of the range of stress fractures in the foot and ankle. Copyright © 2015 Elsevier Ltd. All rights reserved.

Osteoid Osteoma of the Femoral Neck in Athletes

PubMed Central

Cordova, Christopher B.; Dembowski, Scott C.; Johnson, Michael R.; Combs, John J.; Svoboda, Steven J.

2015-01-01

The diagnosis of an intra-articular osteoid osteoma can be a challenging and lengthy process, with reports of delayed diagnosis of greater than 2 years. In the young, athletic patient with an atraumatic onset of groin pain, an overuse injury or muscle strain is the most likely etiology. However, an overuse injury of femoral neck stress fracture must be identified because of the potentially disastrous outcome of fracture completion. The similar clinical presentation of a femoral neck stress fracture and intra-articular osteoid osteoma of the femoral neck can further delay the diagnosis of the osteoid osteoma. In a patient with these differential diagnoses that do not improve with a period of nonweightbearing activity, a more intensive workup must ensue. The purpose of this case report is to describe the initial presentations, subsequent follow-up, and imaging findings leading to the diagnosis of osteoid osteoma as well as to differentiate an osteoid osteoma from femoral neck stress injuries. PMID:26517936

Fracture Properties of Polystyrene Aggregate Concrete after Exposure to High Temperatures

PubMed Central

Tang, Waiching; Cui, Hongzhi; Tahmasbi, Soheil

2016-01-01

This paper mainly reports an experimental investigation on the residual mechanical and fracture properties of polystyrene aggregate concrete (PAC) after exposure to high temperatures up to 800 degrees Celsius. The fracture properties namely, the critical stress intensity factor (KICS), the critical crack tip opening displacement (CTODC) for the Two-Parameter Model, and the fracture energy (GF) for the Fictitious Crack Model were examined using the three-point bending notched beam test, according to the RILEM recommendations. The effects of polystyrene aggregate (PA) content and temperature levels on the fracture and mechanical properties of concrete were investigated. The results showed that the mechanical properties of PAC significantly decreased with increase in temperature level and the extent of which depended on the PA content in the mixture. However, at a very high temperature of 800 °C, all samples showed 80 percent reduction in modulus of elasticity compared to room temperature, regardless of the level of PA content. Fracture properties of control concrete (C) and PAC were influenced by temperature in a similar manner. Increasing temperature from 25 °C to 500 °C caused almost 50% reduction of the fracture energy for all samples while 30% increase in fracture energy was occurred when the temperature increased from 500 °C to 800 °C. It was found that adding more PA content in the mixture lead to a more ductile behaviour of concrete. PMID:28773752

Delayed signatures of underground nuclear explosions

DOE PAGES

Carrigan, Charles R.; Sun, Yunwei; Hunter, Steven L.; ...

2016-03-16

Radionuclide signals from underground nuclear explosions (UNEs) are strongly influenced by the surrounding hydrogeologic regime. One effect of containment is delay of detonation-produced radioxenon reaching the surface as well as lengthening of its period of detectability compared to uncontained explosions. Using a field-scale tracer experiment, we evaluate important transport properties of a former UNE site. Here, we observe the character of signals at the surface due to the migration of gases from the post-detonation chimney under realistic transport conditions. Background radon signals are found to be highly responsive to cavity pressurization suggesting that large local radon anomalies may be anmore » indicator of a clandestine UNE. Computer simulations, using transport properties obtained from the experiment, track radioxenon isotopes in the chimney and their migration to the surface. They show that the chimney surrounded by a fractured containment regime behaves as a leaky chemical reactor regarding its effect on isotopic evolution introducing a dependence on nuclear yield not previously considered. This evolutionary model for radioxenon isotopes is validated by atmospheric observations of radioxenon from a 2013 UNE in the Democratic People’s Republic of Korea (DPRK). In conclusion, our model produces results similar to isotopic observations with nuclear yields being comparable to seismic estimates.« less

Microstructure-dependent fracture toughness (JIC) variations in dissimilar pipe welds for pressure vessel system of nuclear plants

NASA Astrophysics Data System (ADS)

Rathod, Dinesh W.; Pandey, Sunil; Singh, P. K.; Kumar, Suranjit

2017-09-01

In present study, dissimilar metal weld (DMW) joints between SA508Gr.3cl.1 ferritic steel and SS304LN pipes were prepared using Inconel 82/182, and Inconel 52/152 consumables. Metallurgical properties and their influence on fracture toughness of weldment regions and interfacial regions could play a significant role in integrity assessment of these joints. Ni-based consumables exhibit complex metallurgical properties at interfacial regions. The metallurgical characterization and fracture toughness studies of Inconel 82/182 and Inconel 52/152 joints have been carried out for determining the optimum consumable for DMW joint requirements and the effect of microstructure on fracture toughness in weldment regions. The present codes and procedures for integrity assessment of DMW joints have not given due considerations of metallurgical properties. The requirements for metallurgical properties by considering their effect on fracture toughness properties in integrity assessment have been discussed for reliable analysis. Inconel 82/182 is preferred over Inconel 52/152 joints owing to favorable metallurgical and fracture toughness properties across the interfacial and weldment regions.

Scaling of the flow-stiffness relationship in weakly correlated single fractures

NASA Astrophysics Data System (ADS)

Petrovitch, Christopher L.

The remote characterization of the hydraulic properties of fractures in rocks is important in many subsurface projects. Fractures create uncertainty in the hydraulic properties of the subsurface in that their topology controls the amount of flow that can occur in addition to that from the matrix. In turn, the fracture topology is also affected by stress which alters the topology as the stress changes directly. This alteration of fracture topology with stress is captured by fracture specific stiffness. The specific stiffness of a single fracture can be remotely probed from the attenuation and velocity of seismic waves. The hydromechanical coupling of single fractures, i.e. the relationship between flow and stiffness, holds the key to finding a method to remotely characterize a fractures hydraulic properties. This thesis is separated into two parts: (1) a description of the hydromechanical coupling of fractures based on numerical models used to generate synthetic fractures, compute the flow through a fracture, and deform fracture topologies to unravel the scaling function that is fundamental to the hydromechanical coupling of single fractures; (2) a Discontinuous Galerkin (DG) method was developed to accurately simulate the scattered seismic waves from realistic fracture topologies. The scaling regimes of fluid flow and specific stiffness in weakly correlated fractures are identified by using techniques from Percolation Theory and initially treating the two processes separately. The fixed points associated with fluid flow were found to display critical scaling while the fixed points for specific stiffness were trivial. The two processes could be indirectly related because the trivial scaling of the mechanical properties allowed the specific stiffness to be used as surrogate to the void area fraction. The dynamic transport exponent was extracted at threshold by deforming fracture geometries within the effective medium regime (near the ``cubic law'' regime) to the critical regime. From this, a scaling function was defined for the hydromechanical coupling. This scaling function provides the link between fluid flow and fracture specific stiffness so that seismic waves may be used to remotely probe the hydraulic properties of fractures. Then, the DG method is shown to be capable of measuring such fracture specific stiffnesses by numerically measuring the velocity of interface waves when propagated across laboratory measured fracture geometries of Austin Chalk.

Explaining the texture properties of whey protein isolate/starch co-gels from fracture structures.

PubMed

Fu, Wei; Nakamura, Takashi

2017-04-01

The effects of tapioca starch (TS) and potato starch (PS) on texture properties of whey protein isolate (WPI)/starch co-gels were investigated for fracture structures. We focused on two types of WPI network structures. In a fine-stranded structure at pH 6.8, the WPI/TS co-gel fractured similarly to the WPI single gel. The WPI/PS co-gel was broken at a lower strain and lower stress. In a random aggregation at pH 5.8, the WPI/TS co-gel reached a yielding point at a lower strain, whereas the WPI/PS co-gel fractured at a higher strain and higher stress. In the fracture structures, it was revealed that breaks occurred in different places in these cases, which could explain the different texture properties of samples. This study tries to explain the texture properties of WPI/starch co-gels from fracture structures and provides a reference to predict texture properties of the WPI/starch food system.

Lower extremity and pelvic stress fractures in athletes

PubMed Central

Liong, S Y; Whitehouse, R W

2012-01-01

Stress fractures occur following excessive use and are commonly seen in athletes, in whom the lower limbs are frequently involved. Delayed diagnosis and management of these injuries can result in significant long-term damage and athlete morbidity. A high index of suspicion may facilitate diagnosis, but clinical presentation may be non-specific. In this regard, imaging in the form of plain radiograph, CT, MRI and bone scintigraphy may be of value. This article reviews the incidence, presentation, radiological findings and management options for athletes with stress fractures of the lower limb. PMID:22815414

Role of Cbl-PI3K Interaction during Skeletal Remodeling in a Murine Model of Bone Repair.

PubMed

Scanlon, Vanessa; Soung, Do Yu; Adapala, Naga Suresh; Morgan, Elise; Hansen, Marc F; Drissi, Hicham; Sanjay, Archana

2015-01-01

Mice in which Cbl is unable to bind PI3K (YF mice) display increased bone volume due to enhanced bone formation and repressed bone resorption during normal bone homeostasis. We investigated the effects of disrupted Cbl-PI3K interaction on fracture healing to determine whether this interaction has an effect on bone repair. Mid-diaphyseal femoral fractures induced in wild type (WT) and YF mice were temporally evaluated via micro-computed tomography scans, biomechanical testing, histological and histomorphometric analyses. Imaging analyses revealed no change in soft callus formation, increased bony callus formation, and delayed callus remodeling in YF mice compared to WT mice. Histomorphometric analyses showed significantly increased osteoblast surface per bone surface and osteoclast numbers in the calluses of YF fractured mice, as well as increased incorporation of dynamic bone labels. Furthermore, using laser capture micro-dissection of the fracture callus we found that cells lacking Cbl-PI3K interaction have higher expression of Osterix, TRAP, and Cathepsin K. We also found increased expression of genes involved in propagating PI3K signaling in cells isolated from the YF fracture callus, suggesting that the lack of Cbl-PI3K interaction perhaps results in enhanced PI3K signaling, leading to increased bone formation, but delayed remodeling in the healing femora.

Acute flexor tendon injury following midshaft radius and ulna fractures in a paediatric patient.

PubMed

Williams, James; Wharton, Rupert; Peev, Peter; Horwitz, Maxim

2018-06-01

Delayed rupture of the extensor and flexor tendons are recognised complications of distal radius fractures. However, acute flexor tendon rupture in the context of forearm fractures is rare. A twelve-year-old female sustained midshaft fractures of the radius and ulna. Intra-operatively the flexor pollicis longus (FPL) was found to be stripped from its musculotendinous junction at the level of the fracture fragment. The ruptured tendon was repaired using a modified Krackow technique at the time of fracture fixation. The repair was protected in plaster of Paris prior to referral to the paediatric hand clinic. The patient made a full recovery. Flexor tendon injury is a rare but potentially devastating consequence of acute forearm fractures. High energy trauma, significant volar angulation of the fracture fragment and clinical signs of flexor tendon injury should raise suspicion of this injury. A high index of suspicion in conjunction with repeat clinical examination of flexor tendon function should be performed before opting for closed management or intramedullary nailing in paediatric patients.

End-threaded intramedullary positive profile screw ended self-tapping pin (Admit pin) - A cost-effective novel implant for fixing canine long bone fractures.

PubMed

Chanana, Mitin; Kumar, Adarsh; Tyagi, Som Prakash; Singla, Amit Kumar; Sharma, Arvind; Farooq, Uiase Bin

2018-02-01

The current study was undertaken to evaluate the clinical efficacy of end-threaded intramedullary pinning for management of various long bone fractures in canines. This study was conducted in two phases, managing 25 client-owned dogs presented with different fractures. The technique of application of end-threaded intramedullary pinning in long bone fractures was initially standardized in 6 clinical patients presented with long bone fractures. In this phase, end-threaded pins of different profiles, i.e., positive and negative, were used as the internal fixation technique. On the basis of results obtained from standardization phase, 19 client-owned dogs clinically presented with different fractures were implanted with end-threaded intramedullary positive profile screw ended self-tapping pin in the clinical application phase. The patients, allocated randomly in two groups, when evaluated postoperatively revealed slight pin migration in Group-I (negative profile), which resulted in disruption of callus site causing delayed union in one case and large callus formation in other two cases whereas no pin migration was observed in Group-II (positive profile). Other observations in Group-I was reduced muscle girth and delayed healing time as compared to Group-II. In clinical application, phase 21 st and 42 nd day post-operative radiographic follow-up revealed no pin migration in any of the cases, and there was no bone shortening or fragment collapse in end-threaded intramedullary positive profile screw ended self-tapping pin. The end-threaded intramedullary positive profile screw ended self-tapping pin used for fixation of long bone fractures in canines can resist pin migration, pin breakage, and all loads acting on the bone, i.e., compression, tension, bending, rotation, and shearing to an extent with no post-operative complications.

[Early operative treatment of pelvic fractures associated with urethral disruption].

PubMed

Jia, Jian; Guo, Lu-Zeng; Wu, Chang-Lin; Chen, Jia-Geng; Zhang, Tie-Liang; Pei, Fu-Xing

2007-02-15

To evaluate the early operative treatment and clinical results of pelvic fractures associated with urethra disruption. From January 1995 to January 2005, 25 patients suffered from pelvic fractures combined urethra disruption treated by operation were retrospectively analyzed. According to Tile's classification, 1 case was stable pelvic fracture, 17 rotational unstable fractures, and 7 rotational combined vertical unstable fractures. The complete urethra rupture were in 23 cases and incomplete in 2 cases. The operative methods included: (1) emergency open reduction and internal fixation of the pelvis combined primary urethra suturing in 2 cases, partial suturing after realignment in 4 cases, realignment in 2 cases, and urethrovaginal penetrating wound repairing in 1 case; (2) primary urethra realignment only and delayed (range, 7 to 21 days) pelvic internal fixation in 10 cases; (3) early cystostomy and delayed (range, 3 to 21 days) urethra realignment and pelvic internal fixation in 6 cases. The mean follow-up time of all patients was 34 months (range from 6 to 120 months). According to Majeed's evaluation, 17 cases of pelvic injury showed excellent results, 5 good, and 3 fare. After urinary catheter removed, the mean maximal urine flow rate of 19 (76%) patients was 18.6 ml/s and the mean scar length between both disrupted ends on the film of excretion urethrography was 0.51 cm. Five (20%) cases suffered in dysuria needed urethral dilatation or further surgery. One (4%) female could not control urination who need a second-look operation. The primary suprapubic soft tissue avulsion wound infection secondary to retropubic abscess was found in 1 case, posterior urethra-stenosis in 5 cases, sexual impotence in 3 cases, and incontinence in 1 case. The satisfactory reduction and effective fixation of the pelvic fractures is an anatomical basis for receiving "tension-free urethral anastomosis".

Genetic research of fractures in carbonate reservoir: a case study of NT carbonate reservoir in the pre-Caspian basin

NASA Astrophysics Data System (ADS)

Fan, Zifei; Wang, Shuqin; Li, Jianxin; Zhao, Wenqi; Sun, Meng; Li, Weiqiang; Li, Changhai

2018-02-01

The degree of development and characteristics of fractures are key factors for the appraisal of carbonate reservoirs. In this paper, core data and well logging data from the NT oilfield in the Pre-Caspian Basin are used to study the formation mechanism and distribution characteristics of different genetic fractures, and analyze their influence on reservoir properties. Fractures in carbonate reservoirs can be divided into three categories according to their formation mechanism; these are tectonic fracture, dissolved fracture, and diagenetic fracture,which is further divided into interlayer fracture and stylolite. Fractures of different formation mechanism influence fluid seepage in different degree, tectonic fractures possessing strong connecting ability to pores, and dissolved fractures also improving reservoir properties effectively, however, diagenetic fractures contributing relatively little to fluid seepage.

The effects of shot-peening residual stresses on the fracture and crack growth properties of D6AC steel

NASA Technical Reports Server (NTRS)

Elber, W.

1973-01-01

The fracture strength and cyclic crack-growth properties of surface-flawed, shot-peened D6AC steel plate were investigated. For short crack lengths (up to 1.5mm) simple linear elastic fracture mechanics - based only on applied loading - did not predict the fracture strengths. Also, Paris' Law for cyclic crack growth did not correlate the crack-growth behavior. To investigate the effect of shot-peening, additional fracture and crack-growth tests were performed on material which was precompressed to remove the residual stresses left by the shot-peening. Both tests and analysis show that the shot-peening residual stresses influence the fracture and crack-growth properties of the material. The analytical method of compensating for residual stresses and the fracture and cyclic crack-growth test results and predictions are presented.

Effects of shot-peening residual stresses on the fracture and crack-growth properties of D6AC steel

NASA Technical Reports Server (NTRS)

Elber, W.

1974-01-01

The fracture strength and cyclic crack-growth properties of surface-flawed, shot-peened D6AC steel plate were investigated. For short crack lengths (up to 1.5 mm) simple linear elastic fracture mechanics - based only on applied loading - did not predict the fracture strengths. Also, Paris' Law for cyclic crack growth did not correlate the crack-growth behavior. To investigate the effect of shot-peening, additional fracture and crack-growth tests were performed on material which was precompressed to remove the residual stresses left by the shot-peening. Both tests and analysis show that shot-peening residual stresses influence the fracture and crack-growth properties of the material. This report presents the analytical method of compensating for residual stresses and the fracture and cyclic crack-growth test results and predictions.

Bone scanning in the detection of occult fractures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Batillas, J.; Vasilas, A.; Pizzi, W.F.

1981-07-01

The potential role of bone scanning in the early detection of occult fractures following acute trauma was investigated. Technetium 99m pyrophosphate bone scans were obtained in patients with major clinical findings and negative or equivocal roentgenograms following trauma. Bone scanning facilitated the prompt diagnosis of occult fractures in the hip, knee, wrist, ribs and costochondral junctions, sternum, vertebrae, sacrum, and coccyx. Several illustrative cases are presented. Roentgenographic confirmation occurred following a delay of days to weeks and, in some instances, the roentgenographic findings were subtle and could be easily overlooked. This study demonstrates bone scanning to be invaluable and definitivemore » in the prompt detection of occult fractures.« less

a Fractal Network Model for Fractured Porous Media

NASA Astrophysics Data System (ADS)

Xu, Peng; Li, Cuihong; Qiu, Shuxia; Sasmito, Agus Pulung

2016-04-01

The transport properties and mechanisms of fractured porous media are very important for oil and gas reservoir engineering, hydraulics, environmental science, chemical engineering, etc. In this paper, a fractal dual-porosity model is developed to estimate the equivalent hydraulic properties of fractured porous media, where a fractal tree-like network model is used to characterize the fracture system according to its fractal scaling laws and topological structures. The analytical expressions for the effective permeability of fracture system and fractured porous media, tortuosity, fracture density and fraction are derived. The proposed fractal model has been validated by comparisons with available experimental data and numerical simulation. It has been shown that fractal dimensions for fracture length and aperture have significant effect on the equivalent hydraulic properties of fractured porous media. The effective permeability of fracture system can be increased with the increase of fractal dimensions for fracture length and aperture, while it can be remarkably lowered by introducing tortuosity at large branching angle. Also, a scaling law between the fracture density and fractal dimension for fracture length has been found, where the scaling exponent depends on the fracture number. The present fractal dual-porosity model may shed light on the transport physics of fractured porous media and provide theoretical basis for oil and gas exploitation, underground water, nuclear waste disposal and geothermal energy extraction as well as chemical engineering, etc.

Voiding and sexual dysfunctions after pelvic fracture urethral injuries treated with either initial cystostomy and delayed urethroplasty or immediate primary urethral realignment.

PubMed

Aşci, R; Sarikaya, S; Büyükalpelli, R; Saylik, A; Yilmaz, A F; Yildiz, S

1999-08-01

The aim of this study is to evaluate the effects of the different immediate treatment modalities on the sexual and voiding functions in pelvic fracture urethral injuries. The records of 38 male patients with traumatic posterior urethral injuries were reviewed, 18 of whom were treated by initial suprapubic cystostomy and delayed repair (Group 1), and 20 by primary urethral realignment (Group 2). Types of pelvic fractures and urethral injuries were classified according to surgical and radiological findings. Long-term voiding functions were determined by the patient questionnaire, residual urine and uroflow. Sexual functions were also determined by the patient questionnaire and a penile duplex ultrasound study. Mean follow-ups of Groups 1 and 2 were 37 and 39 months, respectively. Membranous urethral disruption extending to the urogenital diaphragm was the most frequent urethral injury (type 3), with incidences of 66.7% and 77.7%, respectively. There were no statistically significant differences in mean age, incidence of pelvic fracture types and urethral injury types between groups (p > 0.05). After the immediate treatments, 16.7% and 55% of the patients regained normal urination, and stricture developed in 83.3% and 45% of the patients, respectively. In 44.4% of the patients in Group 1 and 10% in Group 2, urethral strictures required open urethroplasty (p < 0.05). Erectile impotence before urethroplasty in 17.6% and 20%, anejaculation after urethroplasty in 17.6% and 15% and incontinence in 5.6% and 10% of the patients were found in Groups 1 and 2, respectively (p > 0.05). However, 88.8% and 90% of patients eventually achieved normal urination with complete continence. Sexual and voiding dysfunction after pelvic fracture posterior urethral injury seem to be the result of the injury itself, not of the immediate treatment modalities. In urethral disruption injuries, primary urethral realignment seems more favourable than suprapubic cystostomy and delayed repair.

Fracture Properties of Polystyrene Aggregate Concrete after Exposure to High Temperatures.

PubMed

Tang, Waiching; Cui, Hongzhi; Tahmasbi, Soheil

2016-07-28

This paper mainly reports an experimental investigation on the residual mechanical and fracture properties of polystyrene aggregate concrete (PAC) after exposure to high temperatures up to 800 degrees Celsius. The fracture properties namely, the critical stress intensity factor ( K I C S ), the critical crack tip opening displacement ( CTOD C ) for the Two-Parameter Model, and the fracture energy ( G F ) for the Fictitious Crack Model were examined using the three-point bending notched beam test, according to the RILEM recommendations. The effects of polystyrene aggregate (PA) content and temperature levels on the fracture and mechanical properties of concrete were investigated. The results showed that the mechanical properties of PAC significantly decreased with increase in temperature level and the extent of which depended on the PA content in the mixture. However, at a very high temperature of 800 °C, all samples showed 80 percent reduction in modulus of elasticity compared to room temperature, regardless of the level of PA content. Fracture properties of control concrete (C) and PAC were influenced by temperature in a similar manner. Increasing temperature from 25 °C to 500 °C caused almost 50% reduction of the fracture energy for all samples while 30% increase in fracture energy was occurred when the temperature increased from 500 °C to 800 °C. It was found that adding more PA content in the mixture lead to a more ductile behaviour of concrete.

Total knee arthroplasty and fractures of the tibial plateau

PubMed Central

Softness, Kenneth A; Murray, Ryan S; Evans, Brian G

2017-01-01

Tibial plateau fractures are common injuries that occur in a bimodal age distribution. While there are various treatment options for displaced tibial plateau fractures, the standard of care is open reduction and internal fixation (ORIF). In physiologically young patients with higher demand and better bone quality, ORIF is the preferred method of treating these fractures. However, future total knee arthroplasty (TKA) is a consideration in these patients as post-traumatic osteoarthritis is a common long-term complication of tibial plateau fractures. In older, lower demand patients, ORIF is potentially less favorable for a variety of reasons, namely fixation failure and the need for delayed weight bearing. In some of these patients, TKA can be considered as primary mode of treatment. This paper will review the literature surrounding TKA as both primary treatment and as a salvage measure in patients with fractures of the tibial plateau. The outcomes, complications, techniques and surgical challenges are also discussed. PMID:28251061

Development of a new semi-analytical model for cross-borehole flow experiments in fractured media

USGS Publications Warehouse

Roubinet, Delphine; Irving, James; Day-Lewis, Frederick D.

2015-01-01

Analysis of borehole flow logs is a valuable technique for identifying the presence of fractures in the subsurface and estimating properties such as fracture connectivity, transmissivity and storativity. However, such estimation requires the development of analytical and/or numerical modeling tools that are well adapted to the complexity of the problem. In this paper, we present a new semi-analytical formulation for cross-borehole flow in fractured media that links transient vertical-flow velocities measured in one or a series of observation wells during hydraulic forcing to the transmissivity and storativity of the fractures intersected by these wells. In comparison with existing models, our approach presents major improvements in terms of computational expense and potential adaptation to a variety of fracture and experimental configurations. After derivation of the formulation, we demonstrate its application in the context of sensitivity analysis for a relatively simple two-fracture synthetic problem, as well as for field-data analysis to investigate fracture connectivity and estimate fracture hydraulic properties. These applications provide important insights regarding (i) the strong sensitivity of fracture property estimates to the overall connectivity of the system; and (ii) the non-uniqueness of the corresponding inverse problem for realistic fracture configurations.

Influence of Natural Fractures Cohesive Properties on Geometry of Hydraulic Fracture Networks

NASA Astrophysics Data System (ADS)

Gonzalez-Chavez, M. A.; Dahi Taleghani, A.; Puyang, P.

2014-12-01

An integrated modeling methodology is proposed to analyze hydraulic fracturing jobs in the presence of the natural fracture network in the formation. A propagating hydraulic fracture may arrest, cross, or diverts into a preexisting natural crack depending on fracture properties of rock and magnitude and direction of principal rock stresses. Opening of natural fractures during fracturing treatment could define the effectiveness of the stimulation technique. Here, we present an integrated methodology initiated with lab scale fracturing properties using Double Cantilever Beam tests (DCB) to determine cohesive properties of rock and natural fractures. We used cohesive finite element models to reproduce laboratory results to verify the numerical model for the interaction of the hydraulic fracture and individual cemented natural fractures. Based on the initial investigations, we found out that distribution of pre-existing natural fractures could play a significant role in the final geometry of the induced fracture network; however in practice, there is not much information about the distribution of natural fractures in the subsurface due to the limited access. Hence, we propose a special optimization scheme to generate natural fracture geometry from the location of microseismic events. Accordingly, the criteria of evaluating the fitness of natural fracture realizations is defined as the total minimum distance squares of all microseismic events, which is the sum of minimum square distance for all microseismic events. Moreover, an additional constraint in this problem is that we need to set a minimum distance between fracture grids. Using generated natural fracture realizations, forward field-scale simulations are implemented using cohesive finite element analysis to find the best match with the recorded bottomhole pressure. To show the robustness of the proposed workflow for real field problem, we implemented this technique on available data from several well Chicontepec basin to forecast post-treatment production rate. Our results show a constructive approach to integrate microseismic maps with lab mechanical measurements and bottomhole pressure to estimate the geometry of induced fracture network in the subsurface which does not suffer from any limiting assumption about fracture geometries.

Finite element modeling of the influence of hand position and bone properties on the Colles' fracture load during a fall.

PubMed

Buchanan, Drew; Ural, Ani

2010-08-01

Distal forearm fracture is one of the most frequently observed osteoporotic fractures, which may occur as a result of low energy falls such as falls from a standing height and may be linked to the osteoporotic nature of the bone, especially in the elderly. In order to prevent the occurrence of radius fractures and their adverse outcomes, understanding the effect of both extrinsic and intrinsic contributors to fracture risk is essential. In this study, a nonlinear fracture mechanics-based finite element model is applied to human radius to assess the influence of extrinsic factors (load orientation and load distribution between scaphoid and lunate) and intrinsic bone properties (age-related changes in fracture properties and bone geometry) on the Colles' fracture load. Seven three-dimensional finite element models of radius were created, and the fracture loads were determined by using cohesive finite element modeling, which explicitly represented the crack and the fracture process zone behavior. The simulation results showed that the load direction with respect to the longitudinal and dorsal axes of the radius influenced the fracture load. The fracture load increased with larger angles between the resultant load and the dorsal axis, and with smaller angles between the resultant load and longitudinal axis. The fracture load also varied as a function of the load ratio between the lunate and scaphoid, however, not as drastically as with the load orientation. The fracture load decreased as the load ratio (lunate/scaphoid) increased. Multiple regression analysis showed that the bone geometry and the load orientation are the most important variables that contribute to the prediction of the fracture load. The findings in this study establish a robust computational fracture risk assessment method that combines the effects of intrinsic properties of bone with extrinsic factors associated with a fall, and may be elemental in the identification of high fracture risk individuals as well as in the development of fracture prevention methods including protective falling techniques. The additional information that this study brings to fracture identification and prevention highlights the promise of fracture mechanics-based finite element modeling in fracture risk assessment.

Stress fracture of the pelvis and lower limbs including atypical femoral fractures-a review.

PubMed

Tins, Bernhard J; Garton, Mark; Cassar-Pullicino, Victor N; Tyrrell, Prudencia N M; Lalam, Radhesh; Singh, Jaspreet

2015-02-01

Stress fractures, that is fatigue and insufficiency fractures, of the pelvis and lower limb come in many guises. Most doctors are familiar with typical sacral, tibial or metatarsal stress fractures. However, even common and typical presentations can pose diagnostic difficulties especially early after the onset of clinical symptoms. This article reviews the aetiology and pathophysiology of stress fractures and their reflection in the imaging appearances. The role of varying imaging modalities is laid out and typical findings are demonstrated. Emphasis is given to sometimes less well-appreciated fractures, which might be missed and can have devastating consequences for longer term patient outcomes. In particular, atypical femoral shaft fractures and their relationship to bisphosphonates are discussed. Migrating bone marrow oedema syndrome, transient osteoporosis and spontaneous osteonecrosis are reviewed as manifestations of stress fractures. Radiotherapy-related stress fractures are examined in more detail. An overview of typical sites of stress fractures in the pelvis and lower limbs and their particular clinical relevance concludes this review. Teaching Points • Stress fractures indicate bone fatigue or insufficiency or a combination of these. • Radiographic visibility of stress fractures is delayed by 2 to 3 weeks. • MRI is the most sensitive and specific modality for stress fractures. • Stress fractures are often multiple; the underlying cause should be evaluated. • Infratrochanteric lateral femoral fractures suggest an atypical femoral fracture (AFF); endocrinologist referral is advisable.

Calcaneus Fractures: A Possible Musculoskeletal Emergency.

PubMed

Snoap, Tyler; Jaykel, Matthew; Williams, Cayla; Roberts, Jason

2017-01-01

Calcaneal fractures are commonly seen and treated in the emergency department. There are subsets of calcaneal fractures that pose a high risk to the adjacent soft tissue of the heel and can result in full-thickness tissue necrosis. To identify which calcaneal fractures need to be managed within hours and triaged to the orthopedic team and which can be temporized in a neutral or plantarflexed ankle splint and seen in an outpatient setting. Tongue-type calcaneal fractures and tuberosity fractures must be triaged appropriately within the first few hours of presentation to prevent skin compromise. This requires the emergency physician to understand the radiographic morphology of the fracture as well as the clinical signs of skin compromise. Communication with the orthopedic surgery service is essential and splinting in a specific manner is important to stabilize the soft tissue envelope. Recognizing the calcaneal injury pattern and implementing the correct treatment strategy is paramount to having successful patient outcomes. A delay or error in treatment can turn a closed fracture into an open fracture. Copyright © 2016 Elsevier Inc. All rights reserved.

On the possibility of magnetic nano-markers use for hydraulic fracturing in shale gas mining

NASA Astrophysics Data System (ADS)

Zawadzki, Jaroslaw; Bogacki, Jan

2016-04-01

Recently shale gas production became essential for the global economy, thanks to fast advances in shale fracturing technology. Shale gas extraction can be achieved by drilling techniques coupled with hydraulic fracturing. Further increasing of shale gas production is possible by improving the efficiency of hydraulic fracturing and assessing the spatial distribution of fractures in shale deposits. The latter can be achieved by adding magnetic markers to fracturing fluid or directly to proppant, which keeps the fracture pathways open. After that, the range of hydraulic fracturing can be assessed by measurement of vertical and horizontal component of earth's magnetic field before and after fracturing. The difference in these components caused by the presence of magnetic marker particles may allow to delineate spatial distribution of fractures. Due to the fact, that subterranean geological formations may contain minerals with significant magnetic properties, it is important to provide to the markers excellent magnetic properties which should be also, independent of harsh chemical and geological conditions. On the other hand it is of great significance to produce magnetic markers at an affordable price because of the large quantities of fracturing fluids or proppants used during shale fracturing. Examining the properties of nano-materials, it was found, that they possess clearly superior magnetic properties, as compared to the same structure but having a larger particle size. It should be then possible, to use lower amount of magnetic marker, to obtain the same effect. Although a research on properties of new magnetic nano-materials is very intensive, cheap magnetic nano-materials are not yet produced on a scale appropriate for shale gas mining. In this work we overview, in detail, geological, technological and economic aspects of using magnetic nano-markers in shale gas mining. Acknowledgment This work was supported by the NCBiR under Grant "Electromagnetic method to estimate penetration of proppant in the fracturing process".

Lower extremity trauma: trends in the management of soft-tissue reconstruction of open tibia-fibula fractures.

PubMed

Parrett, Brian M; Matros, Evan; Pribaz, Julian J; Orgill, Dennis P

2006-04-01

Open lower leg fractures with exposed bone or tendon continue to be challenging for plastic surgeons. Microvascular free-tissue transfer increases the ability to close wounds, transfer vascularized bone, and prevent amputation, yet remains a complex, invasive procedure with significant complication rates, donor-site morbidity, and failure rates. This review documents the changing treatment protocol in the authors' institution for these injuries. Two hundred ninety consecutive open tibia-fibula fractures over a 12-year period (1992 to 2003) were retrospectively reviewed and methods and outcomes were compared by grouping the fractures into 4-year intervals. The number of open lower extremity fractures increased, whereas the distribution of Gustilo grade I to III fractures remained unchanged. Overall, free-tissue transfer was performed less frequently and constituted 20 percent of reconstructions in period 1 (1992 to 1995), 11 percent in period 2 (1996 to 1999), and 5 percent in period 3 (2000 to 2003). For the most severe fractures, Gustilo grade III, free-flap reconstruction has decreased significantly, constituting 42 percent, 26 percent, and 11 percent of procedures in periods 1, 2, and 3, respectively. Local flaps for grade III fractures have remained relatively constant throughout the study. In contrast, local wound care for grade III fractures, including skin grafts, delayed primary closures, and secondary intention closures has significantly increased from 22 percent to 49 percent of reconstructions from periods 1 through 3. In 1997, the authors began to use the vacuum-assisted closure device and now use it in nearly half of all open fractures. Despite this trend, there has been no change in infection, amputation, or malunion/nonunion rates and a decrease in reoperation rate with at least 1-year follow-up. These results demonstrate a change in practice, with a trend down the reconstructive ladder, currently using fewer free flaps and more delayed closures and skin grafts with frequent use of the vacuum-assisted closure sponge. Possible reasons for this change are a better understanding of lower leg vascular anatomy and better use of improved wound care technology.

Nano-chemo-mechanical signature of conventional oil-well cement systems: Effects of elevated temperature and curing time

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krakowiak, Konrad J., E-mail: kjkrak@mit.edu; Thomas, Jeffrey J., E-mail: JThomas39@slb.com; Musso, Simone, E-mail: SMusso@slb.com

2015-01-15

With ever more challenging (T,p) environments for cementing applications in oil and gas wells, there is a need to identify the fundamental mechanisms of fracture resistant oil well cements. We report results from a multi-technique investigation of behavior and properties of API class G cement and silica-enriched cement systems subjected to hydrothermal curing from 30 °C to 200 °C; including electron probe microanalysis, X-ray diffraction, thermogravimetry analysis, electron microscopy, neutron scattering (SANS), and fracture scratch testing. The results provide a new insight into the link between system chemistry, micro-texture and micro-fracture toughness. We suggest that the strong correlation found betweenmore » chemically modulated specific surface and fracture resistance can explain the drop in fracture properties of neat oil-well cements at elevated temperatures; the fracture property enhancement in silica-rich cement systems, between 110° and 175 °C; and the drop in fracture properties of such systems through prolonged curing over 1 year at 200 °C.« less

Mechanical properties of kinked silicon nanowires

NASA Astrophysics Data System (ADS)

Jing, Yuhang; Zhang, Chuan; Liu, Yingzhi; Guo, Licheng; Meng, Qingyuan

2015-04-01

Molecular dynamics simulations are used to investigate the mechanical properties of KSiNWs. Our results show that KSiNWs have a much larger fracture strain compared to straight SiNWs. The effects of the periodic length of KSiNWs with symmetric arms and the arm length of the KSiNW with asymmetric arms on the mechanical properties of KSiNWs are studied. The fracture stress of KSiNWs decrease as the periodic length increases. However, the fracture strain of KSiNWs is not dependent on the short periodic length and the fracture strain of KSiNWs will abruptly increase to very large value and then vary slightly as the periodic length increases. In addition, the fracture stress is not dependent on arm length while the fracture strain monotonically increases as the arm length increases. We also investigate the fracture process of KSiNWs. The results in this paper suggest that the KSiNWs with larger fracture strain can be a promising anode materials in high performance Li-ion batteries.

The treatment of posterior urethral disruption associated with pelvic fractures: comparative experience of early realignment versus delayed urethroplasty.

PubMed

Mouraviev, Vladimir B; Coburn, Michael; Santucci, Richard A

2005-03-01

Urological treatment of the patient with severe mechanical trauma and urethral disruption remains controversial. Debate continues regarding the advisability of early realignment vs delayed open urethroplasty. We analyzed our experience with 96 patients to determine the long-term results of the 2 approaches. We retrospectively reviewed the records of 191 men with posterior urethral disruption after severe blunt pelvic injury between 1984 and 2001, of whom 96 survived. Data on 57 patients who underwent early realignment were compared to those on 39 treated with delayed urethroplasty with an average 8.8-year followup (range 1 to 22). All patients were evaluated postoperatively for incontinence, impotence and urethral strictures. The majority of patients had severe concomitant organ injuries (78%) and severe pelvic fractures (76%). The overall mortality rate was 51%. Diagnosis of urethral rupture was based on clinical findings and retrograde urethrography. Strictures developed in 49% of the early realignment group and in 100% of the suprapubic tube group. Impotence (33.6%) and incontinence (17.7%) were less frequent in the early realignment group than in the delayed reconstruction group (42.1% and 24.9%, respectively). Patients with delayed reconstruction underwent an average of 3.1 procedures compared with an average of 1.6 in the early realignment group. Early realignment may provide better outcomes than delayed open urethroplasty after posterior urethral disruption. Increased complications are not seen and, although it can be inconvenient in the massively injured patient, it appears to be a worthwhile maneuver.

Elastic properties and fracture strength of quasi-isotropic graphite/epoxy composites

NASA Technical Reports Server (NTRS)

Sullivan, T. L.

1977-01-01

The layups of the studied laminates are (0, + or - 60) sub s, (0, + or - 45, 90) sub s, (0, + or - 30, + or - 60, 90) sub s (0, + or - 22 1/2, + or - 45, + or - 67 1/2, 90) sub s. The properties determined were tensile modulus, Poisson's ratio, bending stiffness, fracture strength and fracture strain. Measured properties and properties predicted using laminate theory were found to be in reasonable agreement. Reasons for data scatter were determined.

Mechanical properties of contemporary composite resins and their interrelations.

PubMed

Thomaidis, Socratis; Kakaboura, Afrodite; Mueller, Wolf Dieter; Zinelis, Spiros

2013-08-01

To characterize a spectrum of mechanical properties of four representative types of modern dental resin composites and to investigate possible interrelations. Four composite resins were used, a microhybrid (Filtek Z-250), a nanofill (Filtek Ultimate), a nanohybrid (Majesty Posterior) and an ormocer (Admira). The mechanical properties investigated were Flexural Modulus and Flexural Strength (three point bending), Brinell Hardness, Impact Strength, mode I and mode II fracture toughness employing SENB and Brazilian tests and Work of Fracture. Fractographic analysis was carried out in an SEM to determine the origin of fracture for specimens subjected to SENB, Brazilian and Impact Strength testing. The results were statistically analyzed employing ANOVA and Tukey post hoc test (a=0.05) while Pearson correlation was applied among the mechanical properties. Significant differences were found between the mechanical properties of materials tested apart from mode I fracture toughness measured by Brazilian test. The latter significantly underestimated the mode I fracture toughness due to analytical limitations and thus its validity is questionable. Fractography revealed that the origin of fracture is located at notches for fracture toughness tests and contact surface with pendulum for Impact Strength testing. Pearson analysis illustrated a strong correlation between modulus of elasticity and hardness (r=0.87) and a weak negative correlation between Work of Fracture and Flexural Modulus (r=-0.46) and Work of Fracture and Hardness (r=-0.44). Weak correlations were also allocated between Flexural Modulus and Flexural Strength (r=0.40), Flexural Strength and Hardness (r=0.39), and Impact Strength and Hardness (r=0.40). Since the four types of dental resin composite tested exhibited large differences among their mechanical properties differences in their clinical performance is also anticipated. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

EFFECT OF TRITIUM AND DECAY HELIUM ON WELDMENT FRACTURE TOUGHNESS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morgan, M; Scott West, S; Michael Tosten, M

2006-09-26

The fracture toughness data collected in this study are needed to assess the long-term effects of tritium and its decay product on tritium reservoirs. The results show that tritium and decay helium have negative effects on the fracture toughness properties of stainless steel and its weldments. The data and report from this study has been included in a material property database for use in tritium reservoir modeling efforts like the Technology Investment Program ''Lifecycle Engineering for Tritium Reservoirs''. A number of conclusions can be drawn from the data: (1) For unexposed Type 304L stainless steel, the fracture toughness of weldmentsmore » was two to three times higher than the base metal toughness. (2) Tritium exposure lowered the fracture toughness properties of both base metals and weldments. This was characterized by lower J{sub Q} values and lower J-da curves. (3) Tritium-exposed-and-aged base metals and weldments had lower fracture toughness values than unexposed ones but still retained good toughness properties.« less

Semi-analytical model of cross-borehole flow experiments for fractured medium characterization

NASA Astrophysics Data System (ADS)

Roubinet, D.; Irving, J.; Day-Lewis, F. D.

2014-12-01

The study of fractured rocks is extremely important in a wide variety of research fields where the fractures and faults can represent either rapid access to some resource of interest or potential pathways for the migration of contaminants in the subsurface. Identification of their presence and determination of their properties are critical and challenging tasks that have led to numerous fracture characterization methods. Among these methods, cross-borehole flowmeter analysis aims to evaluate fracture connections and hydraulic properties from vertical-flow-velocity measurements conducted in one or more observation boreholes under forced hydraulic conditions. Previous studies have demonstrated that analysis of these data can provide important information on fracture connectivity, transmissivity, and storativity. Estimating these properties requires the development of analytical and/or numerical modeling tools that are well adapted to the complexity of the problem. Quantitative analysis of cross-borehole flowmeter experiments, in particular, requires modeling formulations that: (i) can be adapted to a variety of fracture and experimental configurations; (ii) can take into account interactions between the boreholes because their radii of influence may overlap; and (iii) can be readily cast into an inversion framework that allows for not only the estimation of fracture hydraulic properties, but also an assessment of estimation error. To this end, we present a new semi-analytical formulation for cross-borehole flow in fractured media that links transient vertical-flow velocities measured in one or a series of observation wells during hydraulic forcing to the transmissivity and storativity of the fractures intersected by these wells. Our model addresses the above needs and provides a flexible and computationally efficient semi-analytical framework having strong potential for future adaptation to more complex configurations. The proposed modeling approach is demonstrated in the context of sensitivity analysis for a relatively simple two-fracture synthetic problem, as well as in the context of field-data analysis for fracture connectivity and estimation of corresponding hydraulic properties.

Mechanical and hydraulic properties of rocks related to induced seismicity

USGS Publications Warehouse

Witherspoon, P.A.; Gale, J.E.

1977-01-01

Witherspoon, P.A. and Gale, J.E., 1977. Mechanical and hydraulic properties of rocks related to induced seismicity. Eng. Geol., 11(1): 23-55. The mechanical and hydraulic properties of fractured rocks are considered with regard to the role they play in induced seismicity. In many cases, the mechanical properties of fractures determine the stability of a rock mass. The problems of sampling and testing these rock discontinuities and interpreting their non-linear behavior are reviewed. Stick slip has been proposed as the failure mechanism in earthquake events. Because of the complex interactions that are inherent in the mechanical behavior of fractured rocks, there seems to be no simple way to combine the deformation characteristics of several sets of fractures when there are significant perturbations of existing conditions. Thus, the more important fractures must be treated as individual components in the rock mass. In considering the hydraulic properties, it has been customary to treat a fracture as a parallel-plate conduit and a number of mathematical models of fracture systems have adopted this approach. Non-steady flow in fractured systems has usually been based on a two-porosity model, which assumes the primary (intergranular) porosity contributes only to storage and the secondary (fracture) porosity contributes only to the overall conductivity. Using such a model, it has been found that the time required to achieve quasi-steady state flow in a fractured reservoir is one or two orders of magnitude greater than it is in a homogeneous system. In essentially all of this work, the assumption has generally been made that the fractures are rigid. However, it is clear from a review of the mechanical and hydraulic properties that not only are fractures easily deformed but they constitute the main flow paths in many rock masses. This means that one must consider the interaction of mechanical and hydraulic effects. A considerable amount of laboratory and field data is now available that clearly demonstrates this stress-flow behavior. Two approaches have been used in attempting to numerically model such behavior: (1) continuum models, and (2) discrete models. The continuum approach only needs information as to average values of fracture spacing and material properties. But because of the inherent complexity of fractured rock masses and the corresponding decrease in symmetry, it is difficult to develop an equivalent continuum that will simulate the behavior of the entire system. The discrete approach, on the other hand, requires details of the fracture geometry and material properties of both fractures and rock matrix. The difficulty in obtaining such information has been considered a serious limitation of discrete models, but improved borehole techniques can enable one to obtain the necessary data, at least in shallow systems. The possibility of extending these methods to deeper fracture systems needs more investigation. Such data must be considered when deciding whether to use a continuum or discrete model to represent the interaction of rock and fluid forces in a fractured rock system, especially with regard to the problem of induced seismicity. When one is attempting to alter the pressure distribution in a fault zone by injection or withdrawal of fluids, the extent to which this can be achieved will be controlled in large measure by the behavior of the fractures that communicate with the borehole. Since this is essentially a point phenomenon, i.e., the changes will propagate from a relatively small region around the borehole, the use of a discrete model would appear to be preferable. ?? 1977.

Low-dose TNF augments fracture healing in normal and osteoporotic bone by up-regulating the innate immune response

PubMed Central

Chan, James K; Glass, Graeme E; Ersek, Adel; Freidin, Andrew; Williams, Garry A; Gowers, Kate; Espirito Santo, Ana I; Jeffery, Rosemary; Otto, William R; Poulsom, Richard; Feldmann, Marc; Rankin, Sara M; Horwood, Nicole J; Nanchahal, Jagdeep

2015-01-01

The mechanism by which trauma initiates healing remains unclear. Precise understanding of these events may define interventions for accelerating healing that could be translated to the clinical arena. We previously reported that addition of low-dose recombinant human TNF (rhTNF) at the fracture site augmented fracture repair in a murine tibial fracture model. Here, we show that local rhTNF treatment is only effective when administered within 24 h of injury, when neutrophils are the major inflammatory cell infiltrate. Systemic administration of anti-TNF impaired fracture healing. Addition of rhTNF enhanced neutrophil recruitment and promoted recruitment of monocytes through CCL2 production. Conversely, depletion of neutrophils or inhibition of the chemokine receptor CCR2 resulted in significantly impaired fracture healing. Fragility, or osteoporotic, fractures represent a major medical problem as they are associated with permanent disability and premature death. Using a murine model of fragility fractures, we found that local rhTNF treatment improved fracture healing during the early phase of repair. If translated clinically, this promotion of fracture healing would reduce the morbidity and mortality associated with delayed patient mobilization. PMID:25770819

Complications and functional recovery in treatment of femoral shaft fractures with unreamed intramedullary nailing.

PubMed

Sadic, Sahmir; Custovic, Svemir; Smajic, Nedim; Fazlic, Mirsad; Vujadinovic, Aleksandar; Hrustic, Asmir; Jasarevic, Mahir

2014-01-01

Fracture of the femoral shaft is a common fracture encountered in orthopedic practice. In the 1939, Küntscher introduced the concept of intramedullary nailing for stabilization of long bone fractures. Intramedullary nailing has revolutionized the treatment of fractures. The study included 37 male patients and 13 female patients, averaged 39 +/- 20.5 years (range, 16 to 76 years). There were 31 left femurs and 21 right femurs fractured. 46 fractures were the result of blunt trauma. Low energy trauma was the cause of fractures in six patients, of which five in elderly females. 49 fractures were closed. Healing time given in weeks was 19.36 +/- 6.1. The overall healing rate was 93.6%. There were three (6.25%) major complications nonunion. There were one (2%) delayed union, one (2%) rotational malunion and no infection. The shortening of 1 cm were in two patients. Antercurvatum of 10 degrees was found in one patient. There was no statistically significant reduction of a motion in the hip and knee (p < 0.05). There was statistically significant in the thigh (knee extensors) muscle weakness (p < 0.001). : Intramedullary nailing is the treatment of choice for femoral shaft fractures.

Fractures of the distal tibia treated with polyaxial locking plating.

PubMed

Gao, Hong; Zhang, Chang-Qing; Luo, Cong-Feng; Zhou, Zu-Bin; Zeng, Bing-Fang

2009-03-01

We evaluated the healing rate, complications, and functional outcomes in 32 adult patients with very short metaphyseal fragments in fractures of the distal tibia treated with a polyaxial locking system. The average distance from the distal extent of the fracture to the tibial plafond was 11 mm. All fractures healed and the average time to union was 14 weeks. Six patients (19%) reported occasional local disturbance over the medial malleolus. There were two cases of postoperative superficial infections and evidence of delayed wound healing. Using the American Orthopaedic Foot and Ankle Society ankle score, the average functional score was 87.3 points (of 100 total possible points). Our results show the polyaxial locking plates, which offer more fixation versatility, may be a reasonable treatment option for distal tibia fractures with very short metaphyseal segments.

Rotary self-locking intramedullary nail for long tubular bone fractures.

PubMed

Huang, Zhong-lian; Yang, Hai-long; Xu, Jian-kun; Xia, Xue; Wang, Xin-jia; Song, Jian-xin; Hu, Jun

2013-10-01

Intramedullary nails had been widely used in the treatment of long-bone fractures because of less interference of fractures and center bearing biomechanical advantage. However, it had been also found many shortcomings such as broken nails, delayed healing and was modified in order to achieve better efficacy and reduce complications. The aim of the present study is to compare the efficacy of rotary self-locking intramedullary nails (RSIN) with that of interlocking intramedullary nails (IIN) in the treatment of long-bone fractures. A retrospective study investigated 129 cases with long-bone fractures (36 with femoral fracture, 81 with tibial fracture, and 12 with humeral fracture). The fractures were fixed using either an RSIN or IIN. All patients underwent followup for 12-30 months. All patients in both groups achieved a clinical fracture healing standard and the postoperative affected limb muscle strength and joint function were well restored. The RSIN group required a shorter operative time and the fracture healed faster. There was no significant difference in the hospital stay, intraoperative blood loss or postoperative complications between the two groups. RSIN is used to treat long-bone fractures. Its healing efficacy is equivalent to the IIN. Moreover, the RSIN method is simpler and causes less tissue damage than the IIN, therefore having the advantage of accelerated healing.

Elastic properties and fracture strength of quasi-isotropic graphite/epoxy composites

NASA Technical Reports Server (NTRS)

Sullivan, T. L.

1977-01-01

A research program is described which was devised to determine experimentally the elastic properties in tension and bending of quasi-isotropic laminates made from high-modulus graphite fiber and epoxy. Four laminate configurations were investigated, and determinations were made of the tensile modulus, Poisson's ratio, bending stiffness, fracture strength, and fracture strain. The measured properties are compared with those predicted by laminate theory, reasons for scatter in the experimental data are discussed, and the effect of fiber misalignment on predicted elastic tensile properties is examined. The results strongly suggest that fiber misalignment in combination with variation in fiber volume content is responsible for the scatter in both elastic constants and fracture strength.

Studying physical properties of deformed intact and fractured rocks by micro-scale hydro-mechanical-seismicity model

NASA Astrophysics Data System (ADS)

Raziperchikolaee, Samin

The pore pressure variation in an underground formation during hydraulic stimulation of low permeability formations or CO2 sequestration into saline aquifers can induce microseismicity due to fracture generation or pre-existing fracture activation. While the analysis of microseismic data mainly focuses on mapping the location of fractures, the seismic waves generated by the microseismic events also contain information for understanding of fracture mechanisms based on microseismic source analysis. We developed a micro-scale geomechanics, fluid-flow and seismic model that can predict transport and seismic source behavior during rock failure. This model features the incorporation of microseismic source analysis in fractured and intact rock transport properties during possible rock damage and failure. The modeling method considers comprehensive grains and cements interaction through a bonded-particle-model. As a result of grain deformation and microcrack development in the rock sample, forces and displacements in the grains involved in the bond breakage are measured to determine seismic moment tensor. In addition, geometric description of the complex pore structure is regenerated to predict fluid flow behavior of fractured samples. Numerical experiments are conducted for different intact and fractured digital rock samples, representing various mechanical behaviors of rocks and fracture surface properties, to consider their roles on seismic and transport properties of rocks during deformation. Studying rock deformation in detail provides an opportunity to understand the relationship between source mechanism of microseismic events and transport properties of damaged rocks to have a better characterizing of fluid flow behavior in subsurface formations.

The management of ankle fractures in patients with diabetes.

PubMed

Wukich, Dane K; Kline, Alex J

2008-07-01

Patients with diabetes mellitus have higher complication rates following both open and closed management of ankle fractures. Diabetic patients with neuropathy or vasculopathy have higher complication rates than both diabetic patients without these comorbidities and nondiabetic patients. Unstable ankle fractures in diabetic patients without neuropathy or vasculopathy are best treated with open reduction and internal fixation with use of standard techniques. Patients with neuropathy or vasculopathy are at increased risk for both soft-tissue and osseous complications, including delayed union and nonunion. Careful soft-tissue management as well as stable, rigid internal fixation are crucial to obtaining a good outcome. Prolonged non-weight-bearing and subsequently protected weight-bearing are recommended following both operative and nonoperative management of ankle fractures in patients with diabetes.

In vivo effect of shock-waves on the healing of fractured bone.

PubMed

Augat, P; Claes, L; Suger, G

1995-10-01

In a controlled animal experiment we attempted to clarify the question of whether there is a stimulating effect of extracorporeal shock-waves on the repair process of fractured long bones. As a fracture model we used an osteotomy in the diaphysis of the ovine tibia and an external fixation device. Shock-wave treatment at two levels of intensity and with four different numbers of applied shocks was performed with an electromagnetic acoustic source. Healing of the osteotomized bone was evaluated by biomechanical and radiological investigations on the whole bone as well as on bone sections from areas of the fracture gap and the periosteal fracture callus. We found a non-significant tendency to deterioration of the fracture healing with increasing shock-wave intensities. The study of treatment parameters led neither to significantly different biomechanical outcomes nor to altered radiological results in comparison to the untreated control group. RELEVANCE:--While we cannot comment upon the effectiveness of extracorporeal shock-waves in the delayed treatment of fractures or pseudarthrosis, our results suggest that shock-waves have no beneficial effect in acute fracture repair.

The spectrum of pelvic fracture urethral injuries and posterior urethroplasty in an Italian high-volume centre, from 1980 to 2013.

PubMed

Barbagli, Guido; Sansalone, Salvatore; Romano, Giuseppe; Lazzeri, Massimo

2015-03-01

To describe the emergency and delayed treatment of patients with pelvic fracture urethral injuries (PFUI) presenting to an Italian high-volume centre. In a retrospective, observational study we evaluated the spectrum of PFUI and posterior urethroplasty in an Italian high-volume centre, from 1980 to 2013. Patients requiring emergency treatment for PFUI and delayed treatment for pelvic fracture urethral defects (PFUD) were included. Patients with incomplete clinical records were excluded from the study. Descriptive statistical methods were applied. In all, 159 male patients (median age 35 years) were included in the study. A traffic accident was the most frequent (42.8%) cause of PFUI, and accidents at work were reported as the cause of trauma in 34% of patients. Agricultural accidents decreased from 24.4% to 6.2% over the course of the survey. A suprapubic cystostomy was the most frequent (49%) emergency treatment in patients with PFUI. The use of surgical realignment decreased from 31.7% to 6.2%, and endoscopic realignment increased from 9.7% to 35.3%. A bulbo-prostatic anastomosis was the most frequent (62.9%) delayed treatment in patients with PFUD. The use of the Badenoch pull-through decreased from 19.5% to 2.6%, and endoscopic holmium laser urethrotomy increased from 4.9% to 32.7%. The spectrum of PFUI and subsequent treatment of PFUD has changed greatly over the last 10 years at our centre. These changes involved patient age, aetiology, emergency and delayed treatments, and were found to be related to changes in the economy and lifestyle of the Italian patients.

Mastoid bone fracture presenting as unusual delayed onset of facial nerve palsy.

PubMed

Hsu, Ko-Chiang; Wang, Ann-Ching; Chen, Shyi-Jou

2008-03-01

Delayed-onset facial nerve paralysis is a rather uncommon complication of a mastoid bone fracture for children younger than 10 years. We routinely arrange a cranial computed tomography (CT) for patients encountering initial loss of consciousness, severe headache, intractable vomiting, and/or any neurologic deficit arising from trauma to the head. However, minor symptomatic cranial nerve damage may be missed and the presenting symptom diagnosed as being a peripheral nerve problem. Herein, we report a case of a young boy who presented at our emergency department (ED) 3 days subsequent to his accident, complaining of hearing loss in the right ear and paralysis of the ipsilateral face. Unpredictably, we observed his cranial CT scan revealing a linear fracture of the skull over the right temporal bone involving the right mastoid air cells. The patient was treated conservatively and recovered well without any adverse neurologic consequences. We emphasize that ED physicians should arrange a cranial CT scan for a head-injured child with symptomatic facial nerve palsy, even if there are no symptoms such as severe headache, vomiting, Battle sign, and/or initial loss of consciousness.

Delayed coma in head injury: consider cerebral fat embolism.

PubMed

Metting, Zwany; Rödiger, Lars A; Regtien, Joost G; van der Naalt, Joukje

2009-09-01

To describe a case of a young man with delayed coma after mild head injury, suggestive of cerebral fat embolism (CFE). To underline the value of MR imaging in the differential diagnosis of secondary deterioration in mild head injury. A 21-year-old man admitted with mild head injury after a fall with facial fractures and long bone fractures. He was admitted to the intensive care unit and was mechanically ventilated. Weaning was not possible because of desaturations and pulmonary congestion. Low platelet count and anaemia developed. On several time points during his admission cerebral imaging data were obtained. Non-contrast CT on admission was normal while follow-up MRI showed extensive white matter abnormalities. These imaging abnormalities combined with the clinical presentation suggests cerebral fat embolism (CFE) as the most likely cause of secondary deterioration in our patient. In head injured patients with long bone fractures one should consider cerebral fat embolism. When the classical clinical syndrome is not present, MR imaging is warranted for diagnosis and to exclude other causes of secondary deterioration.

Tibial plafond fractures: limited incision reduction with percutaneous fixation.

PubMed

Salton, Heather L; Rush, Shannon; Schuberth, John

2007-01-01

This study was a retrospective review of 18 patients with 19 pilon fractures treated with limited incision reduction and percutaneous plate fixation of the tibia. Patients were treated with either a 1- or 2-stage protocol. The latter consisted of placement of an external fixator followed by definitive reduction. The emphasis of analysis was placed on the identification of complications to the soft tissue envelope or bone-healing problems within the first 6 months after surgery. A major complication was defined as an unplanned operation within the first 6 months. Minor complications were any superficial wound defects that did not require operative intervention to resolve or any malunion or delayed union. With this protocol, no major complications were encountered. Minor complications were identified in 4 patients (4 fractures) of which 2 were minor wound problems. One patient developed a malunion, and the other had a delayed union. Four patients requested removal of prominent hardware. These results indicate that limited incision reduction and percutaneous plate fixation lead to safe methods of stabilization. The authors also provide guidance and strategies for the consistent execution of this technique.

Pressure sores and hip fractures.

PubMed

Haleem, S; Heinert, G; Parker, M J

2008-02-01

Development of pressure sores during hospital admission causes morbidity and distress to the patient, increases strain on nursing resources, delaying discharge and possibly increasing mortality. A hip fracture in elderly patients is a known high-risk factor for development of pressure sores. We aimed to determine the current incidence of pressure sores and identify those factors which were associated with an increased risk of pressure sores. We retrospectively analysed prospectively collected data of 4654 consecutive patients admitted to a single unit. One hundred and seventy-eight (3.8%) of our patients developed pressure sores. Patient factors that increased the risk of pressure sores were increased age, diabetes mellitus, a lower mental test score, a lower mobility score, a higher ASA score, lower admission haemoglobin and an intra-operative drop in blood pressure. The risk was higher in patients with an extracapsular neck of femur fracture and patients with an increased time interval between admission to hospital and surgery. Our studies indicate that while co-morbidities constitute a substantial risk in an elderly population, the increase in incidence of pressure sores can be reduced by minimising delays to surgery.

Diaphyseal forearm fractures, 20 years after surgical treatment. Is there still an indication for percutaneous fixation?

PubMed

Fernández-Marín, M R; Hidalgo-Pérez, M; Arias-Rodríguez, G; García-Mendoza, A; Prada-Chamorro, E; Domecq-Fernández de Bobadilla, G

This is a retrospective study of 98 diaphyseal forearm fractures in adults, treated by a percutaneous technique with intramedullar Kirchner wires. We reviewed 64 patients with 98 forearm fractures with a radiographic follow-up, assessing the presence of pseudarthrosis or delayed bone union and evaluating functional outcomes with the Anderson and the Disability of the Arm, Shoulder and Hand scale. Clinical and radiological bone union was achieved in an average of 12 weeks. We obtained 77% of excellent and good results following Anderson's scale. There were 4 cases of pseudarthrosis and 6 cases of delayed bone union. This surgical technique provides several advantages, such as a low incidence of complications and a total absence of infections, refractures and iatrogenic neurovascular injuries. It allows a lower hospital stay and a shortening of the surgery time compared with other techniques such as plates and intramedullary nails, that have similar results, in terms of bone union and functional outcomes, as we have verified from the published literature. Copyright © 2017 SECOT. Publicado por Elsevier España, S.L.U. All rights reserved.

Pre-operative urinary tract infection: is it a risk factor for early surgical site infection with hip fracture surgery? A retrospective analysis.

PubMed

Yassa, Rafik Rd; Khalfaoui, Mahdi Y; Veravalli, Karunakar; Evans, D Alun

2017-03-01

The aims of the current study were to determine whether pre-operative urinary tract infections in patients presenting acutely with neck of femur fractures resulted in a delay to surgery and whether such patients were at increased risk of developing post-operative surgical site infections. A retrospective review of all patients presenting with a neck of femur fracture, at a single centre over a one-year period. The hospital hip fracture database was used as the main source of data. UK University Teaching Hospital. All patients ( n  = 460) presenting across a single year study period with a confirmed hip fracture. The presence of pre-operative urinary tract infection, the timing of surgical intervention, the occurrence of post-operative surgical site infection and the pathogens identified. A total of 367 patients were operated upon within 24 hours of admission. Urinary infections were the least common cause of delay. A total of 99 patients (21.5%) had pre-operative urinary tract infection. Post-operatively, a total of 57 (12.4%) patients developed a surgical site infection. Among the latter, 31 (54.4%) did not have a pre-operative urinary infection, 23 (40.4%) patients had a pre-operative urinary tract infection, 2 had chronic leg ulcers and one patient had a pre-operative chest infection. Statistically, there was a strong relationship between pre-operative urinary tract infection and the development of post-operative surgical site infection ( p -value: 0.0005). The results of our study indicate that pre-operative urinary tract infection has a high prevalence amongst those presenting with neck of femur fractures, and this is a risk factor for the later development of post-operative surgical site infection.

Pharmacologically targeting beta-catenin for NF1 associated deficiencies in fracture repair.

PubMed

Baht, Gurpreet S; Nadesan, Puviindran; Silkstone, David; Alman, Benjamin A

2017-05-01

Patients with Neurofibromatosis type 1 display delayed fracture healing and the increased deposition of fibrous tissue at the fracture site. Severe cases can lead to non-union and even congenital pseudarthrosis. Neurofibromatosis type 1 is caused by a mutation in the NF1 gene and mice lacking the Nf1 gene show a fracture repair phenotype similar to that seen in patients. Tissue from the fracture site of patients with Neurofibromatosis type 1 and from mice deficient in the Nf1 gene both show elevated levels of β-catenin protein and activation of β-catenin mediated signaling. Constitutively elevated β-catenin leads to a delayed and fibrous fracture repair process, and (RS)-5-methyl-1-phenyl-1,3,4,6-tetrahydro-2,5-benzoxazocine (Nefopam, a centrally-acting, non-narcotic analgesic agent) inhibits β-catenin mediated signaling during skin wound repair. Here we investigate Nefopam's potential as a modulator of bone repair in mice deficient in Nf1. Mice were treated with Nefopam and investigated for bone fracture repair. Bone marrow stromal cells flushed from the long bones of unfractured mice were treated with Nefopam and investigated for osteogenic potential. Treatment with Nefopam was able to lower the β-catenin level and the Axin2 transcript level in the fracture calluses of Nf1 deficient mice. Cultures from the bone marrow of Nf1 -/- mice had significantly lower osteoblastic colonies and mineralized nodules, which was increased when cells were cultured in the presence of Nefopam. Fracture calluses were harvested and analyzed 14days and 21days after injury. Nf1 -/- calluses had less bone, less cartilage, and higher fibrous tissue content than control calluses. Treatment with Nefopam increased the bone and cartilage content and decreased the fibrous tissue content in Nf1 -/- calluses. These findings present a potential treatment for patients with Neurofibromatosis 1 in the context of bone repair. Since Nefopam is already in use in patient care, it could be rapidly translated to the clinical setting. Copyright © 2017 Elsevier Inc. All rights reserved.

Scratching as a Fracture Process: From Butter to Steel

NASA Astrophysics Data System (ADS)

Akono, A.-T.; Reis, P. M.; Ulm, F.-J.

2011-05-01

We present results of a hybrid experimental and theoretical investigation of the fracture scaling in scratch tests and show that scratching is a fracture dominated process. Validated for paraffin wax, cement paste, Jurassic limestone and steel, we derive a model that provides a quantitative means to relate quantities measured in scratch tests to fracture properties of materials at multiple scales. The scalability of scratching for different probes and depths opens new venues towards miniaturization of our technique, to extract fracture properties of materials at even smaller length scales.

External fixation combined with delayed internal fixation in treatment of tibial plateau fractures with dislocation

PubMed Central

Tao, Xingguang; Chen, Nong; Pan, Fugen; Cheng, Biao

2017-01-01

Abstract The aim of this study was to evaluate the clinical efficacy of external fixation, delayed open reduction, and internal fixation in treating tibial plateau fracture with dislocation. Clinical data of 34 patients diagnosed with tibial plateau fracture complicated with dislocation between January 2009 and May 2015 were retrospectively analyzed. Fifteen patients in group A underwent early calcaneus traction combined with open reduction and internal fixation and 19 in group B received early external fixation combined with delayed open reduction and internal fixation. Operation time, postoperative complication, bone healing time, knee joint range of motion, initial weight-bearing time, Rasmussen tibial plateau score, and knee function score (HSS) were statistically compared between 2 groups. The mean follow-up time was 18.6 months (range: 5–24 months). The mean operation time in group A was 96 minutes, significantly longer than 71 minutes in group B (P < .05). In group A, 5 cases had postoperative complications and 1 in group B (P < .05). The mean bone healing time in group A was 6.9 months (range: 5–9 months) and 6.0 months (range: 5–8 months) in group B (P > .05). In group A, initial weight-bearing time in group A was (14.0 ± 3.6) weeks, significantly differing from (12.9 ± 2.8) weeks in group B (P < 0.05). In group A, the mean knee joint range of motion was 122° (range: 95°–150°) and 135° (range: 100°–160°) in group B (P > 0.05). Rasmussen tibial plateau score in group A was slightly lower than that in group B (P > .05). The excellent rate of knee joint function in group A was 80% and 84.21% in group B (P > .05). External fixation combined with delayed open reduction and internal fixation is a safer and more efficacious therapy of tibial plateau fracture complicated with dislocation compared with early calcaneus traction and open reduction and internal fixation. PMID:29019890

External fixation combined with delayed internal fixation in treatment of tibial plateau fractures with dislocation.

PubMed

Tao, Xingguang; Chen, Nong; Pan, Fugen; Cheng, Biao

2017-10-01

The aim of this study was to evaluate the clinical efficacy of external fixation, delayed open reduction, and internal fixation in treating tibial plateau fracture with dislocation.Clinical data of 34 patients diagnosed with tibial plateau fracture complicated with dislocation between January 2009 and May 2015 were retrospectively analyzed. Fifteen patients in group A underwent early calcaneus traction combined with open reduction and internal fixation and 19 in group B received early external fixation combined with delayed open reduction and internal fixation. Operation time, postoperative complication, bone healing time, knee joint range of motion, initial weight-bearing time, Rasmussen tibial plateau score, and knee function score (HSS) were statistically compared between 2 groups.The mean follow-up time was 18.6 months (range: 5-24 months). The mean operation time in group A was 96 minutes, significantly longer than 71 minutes in group B (P < .05). In group A, 5 cases had postoperative complications and 1 in group B (P < .05). The mean bone healing time in group A was 6.9 months (range: 5-9 months) and 6.0 months (range: 5-8 months) in group B (P > .05). In group A, initial weight-bearing time in group A was (14.0 ± 3.6) weeks, significantly differing from (12.9 ± 2.8) weeks in group B (P < 0.05). In group A, the mean knee joint range of motion was 122° (range: 95°-150°) and 135° (range: 100°-160°) in group B (P > 0.05). Rasmussen tibial plateau score in group A was slightly lower than that in group B (P > .05). The excellent rate of knee joint function in group A was 80% and 84.21% in group B (P > .05).External fixation combined with delayed open reduction and internal fixation is a safer and more efficacious therapy of tibial plateau fracture complicated with dislocation compared with early calcaneus traction and open reduction and internal fixation.

Proximal tibial stress fracture associated with mild osteoarthritis of the knee: case report.

PubMed

Curković, Marko; Kovac, Kristina; Curković, Bozidar; Babić-Naglić, Durda; Potocki, Kristina

2011-03-01

Stress fractures are considered as multifactorial overuse injuries occurring in 0.3%-0.8% of patients suffering from rheumatic diseases, with rheumatoid arthritis being the most common underlying condition. Stress fractures can be classified according to the condition of the bone affected as: 1) fatigue stress fractures occurring when normal bone is exposed to repeated abnormal stresses; and 2) insufficiency stress fractures that occur when normal stress is applied to bone weakened by an underlying condition. Stress fractures are rarely associated with severe forms of knee osteoarthritis, accompanied with malalignment and obesity. We present a patient with a proximal tibial stress fracture associated with mild knee osteoarthritis without associated malalignment or obesity. Stress fracture should be considered when a patient with osteoarthritis presents with sudden deterioration, severe localized tenderness to palpation and localized swelling or periosteal thickening at the pain site and elevated local temperature. The diagnosis of stress fractures in patients with rheumatic diseases may often be delayed because plain film radiographs may not reveal a stress fracture soon after the symptom onset; moreover, evidence of a fracture may never appear on plain radiographs. Triple phase nuclear bone scans and magnetic resonance imaging are more sensitive in the early clinical course than plain films for initial diagnosis.

Results of operative fixation of unstable ankle fractures in geriatric patients.

PubMed

Pagliaro, A J; Michelson, J D; Mizel, M S

2001-05-01

It is widely accepted that operative fixation of unstable ankle fractures yields predictably good outcomes in the general population. The current literature, however reports less acceptable results in the geriatric population age 65 years and older. The current study analyzes the outcome of the surgical treatment of unstable ankle fractures in patients at least 65 years old. Twenty three patient over 65 years old were surgically treated after sustaining 21 (91%) closed and 2 (9%) open grade II unstable ankle fractures. Fractures were classified according to the Danis-Weber and Lauge-Hansen schemes. Fracture type was predominantly Weber B (21/23, 91%), or supination external rotation stage IV (21/23, 91%). Fracture union rate was 100%. There were three significant complications including a lateral wound dehiscence with delayed fibular union in an open fracture dislocation, and two below knee amputations, neither of which was directly related to the fracture treatment. There were three minor complications; one superficial wound infection and two cases of prolonged incision drainage, all of which resolved without further surgical intervention. Complications were associated with open fractures and preexisting systemic disease. These results indicate that open reduction and internal fixation of unstable ankle fractures in geriatric patients is an efficacious treatment regime that with results that are comparable to the general population.

Reactive solute transport in an asymmetrical fracture-rock matrix system

NASA Astrophysics Data System (ADS)

Zhou, Renjie; Zhan, Hongbin

2018-02-01

The understanding of reactive solute transport in a single fracture-rock matrix system is the foundation of studying transport behavior in the complex fractured porous media. When transport properties are asymmetrically distributed in the adjacent rock matrixes, reactive solute transport has to be considered as a coupled three-domain problem, which is more complex than the symmetric case with identical transport properties in the adjacent rock matrixes. This study deals with the transport problem in a single fracture-rock matrix system with asymmetrical distribution of transport properties in the rock matrixes. Mathematical models are developed for such a problem under the first-type and the third-type boundary conditions to analyze the spatio-temporal concentration and mass distribution in the fracture and rock matrix with the help of Laplace transform technique and de Hoog numerical inverse Laplace algorithm. The newly acquired solutions are then tested extensively against previous analytical and numerical solutions and are proven to be robust and accurate. Furthermore, a water flushing phase is imposed on the left boundary of system after a certain time. The diffusive mass exchange along the fracture/rock matrixes interfaces and the relative masses stored in each of three domains (fracture, upper rock matrix, and lower rock matrix) after the water flushing provide great insights of transport with asymmetric distribution of transport properties. This study has the following findings: 1) Asymmetric distribution of transport properties imposes greater controls on solute transport in the rock matrixes. However, transport in the fracture is mildly influenced. 2) The mass stored in the fracture responses quickly to water flushing, while the mass stored in the rock matrix is much less sensitive to the water flushing. 3) The diffusive mass exchange during the water flushing phase has similar patterns under symmetric and asymmetric cases. 4) The characteristic distance which refers to the zero diffusion between the fracture and the rock matrix during the water flushing phase is closely associated with dispersive process in the fracture.

Tritium and decay helium effects on the fracture toughness properties of types 316L, 304L and 21Cr-6Ni-9Mn stainless steels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morgan, M.J.; Tosten, M.H

1994-10-01

J-integral fracture mechanics techniques and electron microscopy observations were used to investigate the effects of tritium and its radioactive decay product, {sup 3}He, on Types 316L, 304L and 21Cr-6Ni-9Mn stainless steels. Tritium-exposed-and-aged steels had lower fracture-toughness values and shallower sloped crack-growth-resistance curves than unexposed steels. Both fracture-toughness parameters decreased with increasing concentrations of {sup 3}He. The fracture-toughness reductions were accompanied by a change in fracture mode from microvoid-nucleation-and-growth processes in control samples to grain-and-twin-boundary fracture in tritium-charged-and-aged samples. Type 316L stainless steel had the highest fracture-toughness values and Type 21Cr-6Ni-9Mn had the lowest. Samples containing {sup 3}He but degassed ofmore » tritium had fracture toughness properties that were similar to uncharged samples. The results indicate that helium bubbles enhance the embrittlement effects of hydrogen by affecting the deformation properties and by increasing localized hydrogen concentrations through trapping effects.« less

Method of Evaluating Hydrogen Embrittlement Susceptibility of Tempered Martensitic Steel Showing Intergranular Fracture

NASA Astrophysics Data System (ADS)

Matsumoto, Yu; Takai, Kenichi

2018-02-01

A stress application method in delayed fracture susceptibility tests was investigated using 1450 MPa class tempered martensitic steel. Its fracture mode under hydrogen charging was mainly intergranular because of its relatively small Si content of 0.21 mass pct. The conditions for consistency in fracture strength between tensile tests and constant load tests (CLTs) were clarified: first, to conduct hydrogen precharging before stress application; and second, to choose a sufficiently low crosshead speed in tensile tests. When hydrogen precharging was not conducted before CLTs, the fracture strength was higher than the values in CLTs with hydrogen charging and in tensile tests. If the crosshead speed was too high, the fracture strength obtained was higher than the values in CLTs. The dependence of the fracture strength on crosshead speed was seen for both notched and smooth bar specimens. These results suggested that plastic deformation, i.e., dislocation motion, was related to intergranular fracture with a tear pattern as well as to quasi-cleavage fracture. In addition, cathodic electrolysis in an alkaline solution containing NaOH should be used as the hydrogen charging method to avoid the effects of corrosion.

Complications in the treatment of adolescent clavicle fractures.

PubMed

Luo, T David; Ashraf, Ali; Larson, A Noelle; Stans, Anthony A; Shaughnessy, William J; McIntosh, Amy L

2015-04-01

This study evaluated the complications associated with the treatment of clavicle fractures in adolescents. All cases of clavicle fractures were identified during an 8-year period between January 2005 and January 2013. During the study period, 153 clavicle fractures occurred in patients between the ages of 14 and 17 years who were treated at the authors' center. Medical records and radiographs were reviewed to determine injury mechanism, fracture pattern, treatment, and complications. Injury severity was assessed as high, medium, and low. Patients with medial or distal metaphyseal fractures and intra-articular fractures were excluded. Of the 153 clavicle fractures, 23 (15.0%) were treated surgically. Compared with the fractures treated nonsurgically, the surgical fractures had greater shortening (mean, 2.0 vs 0.9 cm; P<.001) and were more likely to be comminuted (65.2% vs 23.1%; P<.001). Complications occurred in 21.7% of fractures treated surgically, including refracture (n=2), implant removal for prominence (n=2), and nonunion with implant failure (n=1). One complication was associated with intramedullary nailing, whereas the other 4 complications occurred in clavicles treated with plate fixation. In the non-surgical group, no patients sustained a refracture or malunion who required delayed surgical intervention. Pediatric fellowship-trained orthopedic surgeons treated 78 displaced fractures, resulting in 8 (10.3%) surgeries. Nonpediatric orthopedic specialists treated 46 displaced fractures, 15 (32.6%) of which were treated surgically (P=.0035). Copyright 2015, SLACK Incorporated.

Study of the Influence of Metallurgical Factors on Fatigue and Fracture of Aerospace Structural Materials

DTIC Science & Technology

1989-03-01

11 II. MICROSTRUCTURE/ PROPERTY RELATIONSHIPS IN ADVANCED 12 STRUCTURAL ALLOYS A. Research Objectives 12 B. Summary of Research Efforts 12 1. Fracture...relationship is needed. Figure 5. Correlation between crack growth rates and effective 7 AK for small and large fatigue cracks in a titanium aluminide ...Microstructural/ Property Relationships in Advanced Structural Alloys Table I. Tensile and Fracture Properties of A-Fe-X Alloys in the 13 LT

Comparison of Surface Properties in Natural and Artificially Generated Fractures in a Crystalline Rock

NASA Astrophysics Data System (ADS)

Vogler, Daniel; Walsh, Stuart D. C.; Bayer, Peter; Amann, Florian

2017-11-01

This work studies the roughness characteristics of fracture surfaces from a crystalline rock by analyzing differences in surface roughness between fractures of various types and sizes. We compare the surface properties of natural fractures sampled in situ and artificial (i.e., man-made) fractures created in the same source rock under laboratory conditions. The topography of the various fracture types is compared and characterized using a range of different measures of surface roughness. Both natural and artificial, and tensile and shear fractures are considered, along with the effects of specimen size on both the geometry of the fracture and its surface characterization. The analysis shows that fracture characteristics are substantially different between natural shear and artificial tensile fractures, while natural tensile fracture often spans the whole result domain of the two other fracture types. Specimen size effects are also evident, not only as scale sensitivity in the roughness metrics, but also as a by-product of the physical processes used to generate the fractures. Results from fractures generated with Brazilian tests show that fracture roughness at small scales differentiates fractures from different specimen sizes and stresses at failure.

Understanding the Geometry of Connected Fracture Flow with Multiperiod Oscillatory Hydraulic Tests.

PubMed

Sayler, Claire; Cardiff, Michael; Fort, Michael D

2018-03-01

An understanding of the spatial and hydraulic properties of fast preferential flow pathways in the subsurface is necessary in applications ranging from contaminant fate and transport modeling to design of energy extraction systems. One method for the characterization of fracture properties over interwellbore scales is Multiperiod Oscillatory Hydraulic (MOH) testing, in which the aquifer response to oscillatory pressure stimulations is observed. MOH tests were conducted on isolated intervals of wells in siliciclastic and carbonate aquifers in southern Wisconsin. The goal was to characterize the spatial properties of discrete fractures over interwellbore scales. MOH tests were conducted on two discrete fractured intervals intersecting two boreholes at one field site, and a nest of three piezometers at another field site. Fracture diffusivity estimates were obtained using analytical solutions that relate diffusivity to observed phase lag and amplitude decay. In addition, MOH tests were used to investigate the spatial extent of flow using different conceptual models of fracture geometry. Results indicated that fracture geometry at both field sites can be approximated by permeable two-dimensional fracture planes, oriented near-horizontally at one site, and near-vertically at the other. The technique used on MOH field data to characterize fracture geometry shows promise in revealing fracture network characteristics important to groundwater flow and transport. © 2017, National Ground Water Association.

[Reasons for proximal femoral fracture surgery delays : Analysis of the structured dialog in Rheinland-Pfalz].

PubMed

Ruffing, T; Haunschild, M; Egenolf, M; Eymann, W; Jost, D; Wallmen, G; Burmeister, C

2016-11-01

For the "preoperative stay" quality indicator , which is part of the external quality assurance for proximal femoral fractures (module 17/1), a tolerance range for surgery within 48 h after admission of ≤15 % is given. The structured dialog (2014) in Rheinland-Pfalz was analyzed with respect to reasons for delaying surgery for more than 48 h after admission. A total of 331 cases were analyzed. In 60.7 % patient-related reasons and in 13.3 % administrative reasons were found. In 9.1 % the statements were not feasible. Due to a lack of software-related specifications in 7.3 % a wrong preoperative length of stay was generated. Wrong coding or a computer-related problem was found in 6.6 %. The most common reason for delay was the intake of an anticoagulant (25.7 %). The significance of the quality indicator "Preoperative stay" without division into whether this was administrative or patient-related must be considered critically.

Open tibial fractures grade IIIC treated successfully with external fixation, negative-pressure wound therapy and recombinant human bone morphogenetic protein 7.

PubMed

Babiak, Ireneusz

2014-10-01

The aim of the therapy in open tibial fractures grade III was to cover the bone with soft tissue and achieve healed fracture without persistent infection. Open tibial fractures grade IIIC with massive soft tissue damage require combined orthopaedic, vascular and plastic-reconstructive procedures. Negative-pressure wound therapy (NPWT), used in two consecutive cases with open fracture grade IIIC of the tibia diaphysis, healed extensive soft tissue defect with exposure of the bone. NPWT eventually allowed for wound closure by split skin graft within 21-25 days. Ilizarov external fixator combined with application of recombinant human bone morphogenetic protein-7 at the site of delayed union enhanced definitive bone healing within 16-18 months. © 2012 The Authors. International Wound Journal © 2012 Medicalhelplines.com Inc and John Wiley & Sons Ltd.

Coupling Hydraulic Fracturing Propagation and Gas Well Performance for Simulation of Production in Unconventional Shale Gas Reservoirs

NASA Astrophysics Data System (ADS)

Wang, C.; Winterfeld, P. H.; Wu, Y. S.; Wang, Y.; Chen, D.; Yin, C.; Pan, Z.

2014-12-01

Hydraulic fracturing combined with horizontal drilling has made it possible to economically produce natural gas from unconventional shale gas reservoirs. An efficient methodology for evaluating hydraulic fracturing operation parameters, such as fluid and proppant properties, injection rates, and wellhead pressure, is essential for the evaluation and efficient design of these processes. Traditional numerical evaluation and optimization approaches are usually based on simulated fracture properties such as the fracture area. In our opinion, a methodology based on simulated production data is better, because production is the goal of hydraulic fracturing and we can calibrate this approach with production data that is already known. This numerical methodology requires a fully-coupled hydraulic fracture propagation and multi-phase flow model. In this paper, we present a general fully-coupled numerical framework to simulate hydraulic fracturing and post-fracture gas well performance. This three-dimensional, multi-phase simulator focuses on: (1) fracture width increase and fracture propagation that occurs as slurry is injected into the fracture, (2) erosion caused by fracture fluids and leakoff, (3) proppant subsidence and flowback, and (4) multi-phase fluid flow through various-scaled anisotropic natural and man-made fractures. Mathematical and numerical details on how to fully couple the fracture propagation and fluid flow parts are discussed. Hydraulic fracturing and production operation parameters, and properties of the reservoir, fluids, and proppants, are taken into account. The well may be horizontal, vertical, or deviated, as well as open-hole or cemented. The simulator is verified based on benchmarks from the literature and we show its application by simulating fracture network (hydraulic and natural fractures) propagation and production data history matching of a field in China. We also conduct a series of real-data modeling studies with different combinations of hydraulic fracturing parameters and present the methodology to design these operations with feedback of simulated production data. The unified model aids in the optimization of hydraulic fracturing design, operations, and production.

Approaching a universal scaling relationship between fracture stiffness and fluid flow

NASA Astrophysics Data System (ADS)

Pyrak-Nolte, Laura J.; Nolte, David D.

2016-02-01

A goal of subsurface geophysical monitoring is the detection and characterization of fracture alterations that affect the hydraulic integrity of a site. Achievement of this goal requires a link between the mechanical and hydraulic properties of a fracture. Here we present a scaling relationship between fluid flow and fracture-specific stiffness that approaches universality. Fracture-specific stiffness is a mechanical property dependent on fracture geometry that can be monitored remotely using seismic techniques. A Monte Carlo numerical approach demonstrates that a scaling relationship exists between flow and stiffness for fractures with strongly correlated aperture distributions, and continues to hold for fractures deformed by applied stress and by chemical erosion as well. This new scaling relationship provides a foundation for simulating changes in fracture behaviour as a function of stress or depth in the Earth and will aid risk assessment of the hydraulic integrity of subsurface sites.

Fracture properties of concrete specimens made from alkali activated binders

NASA Astrophysics Data System (ADS)

Šimonová, Hana; Kucharczyková, Barbara; Topolář, Libor; Bílek, Vlastimil, Jr.; Keršner, Zbyněk

2017-09-01

The aim of this paper is to quantify crack initiation and other fracture properties - effective fracture toughness and specific fracture energy - of two types of concrete with an alkali activated binder. The beam specimens with a stress concentrator were tested in a three-point bending test after 28, 90, and 365 days of maturing. Records of fracture tests in the form of load versus deflection (P-d) diagrams were evaluated using effective crack model and work-of-fracture method and load versus mouth crack opening displacement (P-CMOD) diagrams were evaluated using the Double-K fracture model. The initiation of cracks during the fracture tests for all ages was also monitored by the acoustic emission method. The higher value of monitored mechanical fracture parameters of concrete with alkali activated blast furnace slag were achieved with substitution blast furnace slag by low calcium fly ash in comparison with substitution by cement kiln dust.

The burden of previous fractures in hip fracture patients. The Break Study.

PubMed

Maggi, Stefania; Siviero, Paola; Gonnelli, Stefano; Caffarelli, Carla; Gandolini, Giorgio; Cisari, Carlo; Rossini, Maurizio; Iolascon, Giovanni; Mauro, Giulia Letizia; Nuti, Ranuccio; Crepaldi, Gaetano

2011-06-01

A positive history of fractures in older patients with hip fracture is common. We determined the risk factors associated with a positive history of fractures and the profile of care in hip fracture patients. In the Break Study, we enrolled 1249 women aged ≥60 years, seeking care for a hip fracture. Baseline information included age, body mass index, lifestyle (smoking habit, alcohol consumption), patient's history of fracture after the age of 50 years, family history of fragility fracture and health status (presence of comorbidity, use of specific drugs, pre-fracture walking ability, type of fracture, time to surgery, type of surgery, osteoporosis treatment). In the multivariable model age, smoking, family history, treatment with antiplatelet, anticoagulants and anticonvulsants, were significant predictors of a positive history of fracture. More than 70% of patients underwent surgery more than 48 hours after admission. About 50% were discharged with a treatment for osteoporosis, but more than 30% only with calcium and vitamin D. In conclusion, factors associated with a positive history of fracture are the traditional risk factors, suggesting that they continue to have a negative impact on health even at older ages. Selected drugs, such as antiplatelet and anticoagulants, deserve further consideration as significant factors associated with fractures. Given that delay in surgery is a major cause of mortality and disability, while treatment for osteoporosis decreases significantly the risk of recurrent fractures and disability, interventions to modify these patterns of care are urgently needed.

Tension band plating of a nonunion anterior tibial stress fracture in an athlete.

PubMed

Merriman, Jarrad A; Villacis, Diego; Kephart, Curtis J; Rick Hatch, George F

2013-07-01

The authors present a rare technique of tension band plating of the anterior tibia in the setting of a nonunion stress fracture. Surgical management with an intramedullary nail is a viable and proven option for treating such injuries. However, in treating elite athletes, legitimate concerns exist regarding the surgical disruption of the extensor mechanism and the risk of anterior knee pain associated with intramedullary nail use. The described surgical technique demonstrates the use of tension band plating as an effective treatment of delayed union and nonunion anterior tibial stress fractures in athletes without the potential risks of intramedullary nail insertion. Copyright 2013, SLACK Incorporated.

Talar Fractures in Children: A Possible Injury After Go-Karting Accidents.

PubMed

Kamphuis, Saskia J M; Meijs, Claartje M E M; Kleinveld, Sanne; Diekerhof, Carel H; van der Heijden, Frank H W M

2015-01-01

Go-karting is an increasingly popular high-energy sport enjoyed by both children and adults. Because of the speeds involved, accidents involving go-karts can lead to serious injury. We describe 6 talar fractures in 4 patients that resulted from go-karting accidents. Talar fractures can cause severe damage to the tibiotalar joint, talocalcaneal or subtalar joint, and the talonavicular joint. This damage can, in turn, lead to complications such as avascular necrosis, arthritis, nonunion, delayed union, and neuropraxia, which have the potential to cause long-term disability in a child. Copyright © 2015 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Strain Rate Dependency of Fracture Toughness, Energy Release Rate and Geomechanical Attributes of Select Indian Shales

NASA Astrophysics Data System (ADS)

Mahanta, B.; Vishal, V.; Singh, T. N.; Ranjith, P.

2016-12-01

In addition to modern improved technology, it requires detailed understanding of rock fractures for the purpose of enhanced energy extraction through hydraulic fracturing of gas shales and geothermal energy systems. The understanding of rock fracture behavior, patterns and properties such as fracture toughness; energy release rate; strength and deformation attributes during fracturing hold significance. Environmental factors like temperature, pressure, humidity, water vapor and experimental condition such as strain rate influence the estimation of these properties. In this study, the effects of strain rates on fracture toughness, energy release rate as well as geomechanical properties like uniaxial compressive strength, Young's modulus, failure strain, tensile strength, and brittleness index of gas shales were investigated. In addition to the rock-mechanical parameters, the fracture toughness and the energy release rates were measured for three different modes viz. mode I, mixed mode (I-II) and mode II. Petrographic and X-ray diffraction (XRD) analyses were performed to identify the mineral composition of the shale samples. Scanning electron microscope (SEM) analyses were conducted to have an insight about the strain rate effects on micro-structure of the rock. The results suggest that the fracture toughness; the energy release rate as well as other geomechanical properties are a function of strain rates. At high strain rates, the strength and stiffness of shale increases which in turn increases the fracture toughness and the energy release rate of shale that may be due to stress redistribution during grain fracturing. The fracture toughness and the strain energy release rates for all the modes (I/I-II/II) are comparable at lower strain rates, but they vary considerably at higher strain rates. In all the cases, mode I and mode II fracturing requires minimum and maximum applied energy, respectively. Mode I energy release rate is maximum, compared to the other modes.

Fluid driven fracture mechanics in highly anisotropic shale: a laboratory study with application to hydraulic fracturing

NASA Astrophysics Data System (ADS)

Gehne, Stephan; Benson, Philip; Koor, Nick; Enfield, Mark

2017-04-01

The finding of considerable volumes of hydrocarbon resources within tight sedimentary rock formations in the UK led to focused attention on the fundamental fracture properties of low permeability rock types and hydraulic fracturing. Despite much research in these fields, there remains a scarcity of available experimental data concerning the fracture mechanics of fluid driven fracturing and the fracture properties of anisotropic, low permeability rock types. In this study, hydraulic fracturing is simulated in a controlled laboratory environment to track fracture nucleation (location) and propagation (velocity) in space and time and assess how environmental factors and rock properties influence the fracture process and the developing fracture network. Here we report data on employing fluid overpressure to generate a permeable network of micro tensile fractures in a highly anisotropic shale ( 50% P-wave velocity anisotropy). Experiments are carried out in a triaxial deformation apparatus using cylindrical samples. The bedding planes are orientated either parallel or normal to the major principal stress direction (σ1). A newly developed technique, using a steel guide arrangement to direct pressurised fluid into a sealed section of an axially drilled conduit, allows the pore fluid to contact the rock directly and to initiate tensile fractures from the pre-defined zone inside the sample. Acoustic Emission location is used to record and map the nucleation and development of the micro-fracture network. Indirect tensile strength measurements at atmospheric pressure show a high tensile strength anisotropy ( 60%) of the shale. Depending on the relative bedding orientation within the stress field, we find that fluid induced fractures in the sample propagate in two of the three principal fracture orientations: Divider and Short-Transverse. The fracture progresses parallel to the bedding plane (Short-Transverse orientation) if the bedding plane is aligned (parallel) with the direction of σ1. Conversely, the crack plane develops perpendicular to the bedding plane, if the bedding plane is orientated normal to σ1. Fracture initiation pressures are higher in the Divider orientation ( 24MPa) than in the Short-Transverse orientation ( 14MPa) showing a tensile strength anisotropy ( 42%) comparable to ambient tensile strength results. We then use X-Ray Computed Tomography (CT) 3D-images to evaluate the evolved fracture network in terms of fracture pattern, aperture and post-test water permeability. For both fracture orientations, very fine, axial fractures evolve over the entire length of the sample. For the fracturing in the Divider orientation, it has been observed, that in some cases, secondary fractures are branching of the main fracture. Test data from fluid driven fracturing experiments suggest that fracture pattern, fracture propagation trajectories and fracturing fluid pressure (initiation and propagation pressure) are predominantly controlled by the interaction between the anisotropic mechanical properties of the shale and the anisotropic stress environment. The orientation of inherent rock anisotropy relative to the principal stress directions seems to be the main control on fracture orientation and required fracturing pressure.

The relation of microdamage to fracture and material property degradation in human cortical bone tissue

NASA Astrophysics Data System (ADS)

Akkus, Ozan

This dissertation investigates the relation of microdamage to fracture and material property degradation of human cortical bone tissue. Fracture resistance and fatigue crack growth of microcracks were examined experimentally and material property degradation was examined through theoretical modeling. To investigate the contribution of microdamage to static fracture resistance, fracture toughness tests were conducted in the transverse and longitudinal directions to the osteonal orientation of normal bone tissue. Damage accumulation was monitored by acoustic emission during testing and was spatially observed by histological observation following testing. The results suggested that the propagation of the main crack involved weakening of the tissue by diffuse damage at the fracture plane and by formation of linear microcracks away from the fracture plane for the transverse specimens. For the longitudinal specimens, growth of the main crack occurred in the form of separations at lamellar interfaces. Acoustic emission results supported the histological observations. To investigate the contribution of ultrastructure to static fracture resistance, fracture toughness tests were conducted after altering the collagen phase of the bone tissue by gamma radiation. A significant decrease in the fracture toughness, Work-to-Fracture and the amount damage was observed due to irradiation in both crack growth directions. For cortical bone irradiated at 27.5kGy, fracture toughness is reduced due to the inhibition of damage formation at and near the crack tip. Microcrack fatigue crack growth and arrest were investigated through observations of surface cracks during cyclic loading. At the applied cyclic stresses, the microcracks propagated and arrested in less than 10,000 cycles. In addition, the microcracks were observed not to grow beyond a length of 150mum and a DeltaK of 0.5MNm-3/2, supporting a microstructural barrier concept. Finally, the contribution of linear microcracks to material property degradation was examined by developing a theoretical micromechanical damage model. The model was compared to experimentally induced damage in bone tissue. The percent contribution of linear microcracks to the total degradation was predicted to be less than 5%, indicating that diffuse damage or an unidentified form of damage is primarily responsible for material property degradation in human cortical bone tissue.

Anatomically precontoured LCP for delayed union of a medial third clavicle fracture. Case report with review of the literature.

PubMed

Siebenlist, S; Sandmann, G; Kirchhoff, C; Biberthaler, P; Neumaier, M

2013-01-01

Fractures of the medial clavicle third are rare injuries. Even in case of significant fracture displacement, their therapeutic management has been nonoperative. Recently, surgical intervention has become mandatory for displaced fractures types to prevent non-union and functional complaints, but the optimal operative strategy is being discussed controversially. We describe the case of a 63-year-old male patient with a significantly displaced medial clavicle fracture after failed conservative treatment resulting in restricted, painful shoulder function. The patient underwent open reduction and osteosynthesis with an anatomically precontoured locking compression plate (LCP). One year after surgery the patient is free of complaints and has returned to his preinjury activity level without any functional restrictions. As a not yet reported operative approach, anatomically preshaped locking plating seems to be an effective fixation method for displaced fractures of the medial clavicle third. The operative management is described in detail and discussed with the current literature. Based on the presented case, we underline the statement that displaced medial clavicle fractures should be surgically addressed to avoid late damage.

Multiple fractures and impaired bone metabolism in Wolfram syndrome: a case report.

PubMed

Catalano, Antonino; Bellone, Federica; Cicala, Giuseppe; Giandalia, Annalisa; Morabito, Nunziata; Cucinotta, Domenico; Russo, Giuseppina Tiziana

2017-01-01

Wolfram Syndrome (WS) is a rare and lethal disease characterized by optic atrophy, diabetes mellitus, diabetes insipidus, and hearing loss. To date, osteoporotic related fractures have not been reported in affected patients. Here, we describe the case of a man affected by WS complicated by several bone fragility fractures. A 50-year-old Caucasian man was hospitalized because of tibia and fibula fractures. His clinical features included diabetes mellitus, diabetes insipidus, optic atrophy and deafness that were consistent with an unrecognized WS diagnosis, which was confirmed by the identification of a specific mutation in gene WFS1 encoding wolframin. Bone mineral density by phalangeal quantitative ultrasound demonstrated severe osteoporosis, with high serum levels of surrogate markers of bone turn-over. Previously unidentified rib fractures were also detected. To the best of our knowledge, this is the first report of osteoporotic related fractures in a patient affected by WS. Although no effective treatments are currently available to delay the progression of the disease, this case report suggests to evaluate fracture risk in the diagnostic work-up of WS.

CORRELATION BETWEEN TIME UNTIL SURGICAL TREATMENT AND MORTALITY AMONG ELDERLY PATIENTS WITH FRACTURES AT THE PROXIMAL END OF THE FEMUR.

PubMed

Arliani, Gustavo Gonçalves; da Costa Astur, Diego; Linhares, Glauber Kazuo; Balbachevsky, Daniel; Fernandes, Hélio Jorge Alvachian; Dos Reis, Fernando Baldy

2011-01-01

The primary aim of this study was to analyze the possible association between delay in receiving surgical treatment and mortality among elderly patients with fractures at the proximal end of the femur. 269 patients with fractures at the proximal end of the femur (femur neck and intertrochanteric fractures) who were treated surgically at Hospital São Paulo, UNIFESP, São Paulo, between January 2003 and December 2007, were studied. The following attributes were analyzed and compared with the literature relating to this subject: sex, age, type of fracture, classification of the fracture, affected side, synthesis used, trauma mechanism, length of hospitalization, waiting time for surgery, associated comorbidities, hemogram on admission, type of anesthesia, need for blood transfusion, day of the week and season of the year of the fracture. The study showed that higher mortality correlated with higher numbers of clinical comorbidities, longer hospitalization and use of general anesthesia during the surgery. There was no association between the time spent waiting for surgery and mortality.

Talar injuries--the orthopaedic challenge.

PubMed

Lesić, Aleksandar R; Zagorac, Slavisa G; Bumbasirević, Marko Z

2012-01-01

Injuries of the talus represents an important part of the foot and ankle trauma. Since talar bone connect the lower limb and foot, the sequelas of its trauma could have significant influence on the function of the whole lower limb and gait. The specific vascularization of the talus results in delayed union and even in the avascular necrosis. The diagnosis of the fractures of the talus can be made on the x-rays, but sometimes real picture of the fracture pattern can be seen only in the CT scans. Ocult fractures such as osteochondral fractures and avascular necrosis can be exactly detected on MRI in aim not to be overlookded as the ankle sprain diagnosis. The precise reduction and stable internal fixation is mandatory in the treatment to enable the anatomical position of the talonavicular, talocrural and subtalar joint and to make possible early motion and rehabilitation, without weight bearing. On the other hand, crushed fractures, open fractures and the Hawkins III-IV fractures with the dislocations of the talar body sometimes needs salvage procedures like Blair or tibio-talar or tibio-calcaneal fusion.

[Surgical treatment of tibial nonunion after wounding by high velocity missile and external fixators: a case report].

PubMed

Golubović, Ivan; Vukašinović, Zoran; Stojiljković, Predrag; Golubović, Zoran; Stojiljković, Danilo; Radovanović, Zoran; Ilić, Nenad; Najman, Stevo; Višnjić, Aleksandar; Arsić, Stojanka

2012-01-01

The missiles of modern firearms can cause severe fractures of the extremity. High velocity missile fractures of the tibia are characterized by massive tissue destruction and primary contamination with polymorphic bacteria. Treatment of these fractures is often complicated by delayed healing, poor position healing, nonhealing and bone tissue infection. We present the management of tibial nonunion after wounding by high velocity missile and primary treatment by external fixation in a 25-year-old patient. The patient was primarily treated with external fixation and reconstructive operations of the soft tissue without union of the fracture. Seven months after injury we placed a compression-distraction external fixator type Mitkovic and started with compression and distraction in the fracture focus after osteotomy of the fibula and autospongioplasty. We recorded satisfactory fracture healing and good functional outcome. Contamination and devitalization of the soft-tissue envelope increase the risk of infection and nonunion in fractures after wounding by high velocity missile. The use of the compression-distraction external fixator type Mitkovic may be an effective method in nonunions of the tibia after this kind of injury.

Fractures of the proximal fifth metatarsal: percutaneous bicortical fixation.

PubMed

Mahajan, Vivek; Chung, Hyun Wook; Suh, Jin Soo

2011-06-01

Displaced intraarticular zone I and displaced zone II fractures of the proximal fifth metatarsal bone are frequently complicated by delayed nonunion due to a vascular watershed. Many complications have been reported with the commonly used intramedullary screw fixation for these fractures. The optimal surgical procedure for these fractures has not been determined. All these observations led us to evaluate the effectiveness of percutaneous bicortical screw fixation for treating these fractures. Twenty-three fractures were operatively treated by bicortical screw fixation. All the fractures were evaluated both clinically and radiologically for the healing. All the patients were followed at 2 or 3 week intervals till fracture union. The patients were followed for an average of 22.5 months. Twenty-three fractures healed uneventfully following bicortical fixation, with a mean healing time of 6.3 weeks (range, 4 to 10 weeks). The average American Orthopaedic Foot & Ankle Society (AOFAS) score was 94 (range, 90 to 99). All the patients reported no pain at rest or during athletic activity. We removed the implant in all cases at a mean of 23.2 weeks (range, 18 to 32 weeks). There was no refracture in any of our cases. The current study shows the effectiveness of bicortical screw fixation for displaced intraarticular zone I fractures and displaced zone II fractures. We recommend it as one of the useful techniques for fixation of displaced zone I and II fractures.

Low-dose TNF augments fracture healing in normal and osteoporotic bone by up-regulating the innate immune response.

PubMed

Chan, James K; Glass, Graeme E; Ersek, Adel; Freidin, Andrew; Williams, Garry A; Gowers, Kate; Espirito Santo, Ana I; Jeffery, Rosemary; Otto, William R; Poulsom, Richard; Feldmann, Marc; Rankin, Sara M; Horwood, Nicole J; Nanchahal, Jagdeep

2015-05-01

The mechanism by which trauma initiates healing remains unclear. Precise understanding of these events may define interventions for accelerating healing that could be translated to the clinical arena. We previously reported that addition of low-dose recombinant human TNF (rhTNF) at the fracture site augmented fracture repair in a murine tibial fracture model. Here, we show that local rhTNF treatment is only effective when administered within 24 h of injury, when neutrophils are the major inflammatory cell infiltrate. Systemic administration of anti-TNF impaired fracture healing. Addition of rhTNF enhanced neutrophil recruitment and promoted recruitment of monocytes through CCL2 production. Conversely, depletion of neutrophils or inhibition of the chemokine receptor CCR2 resulted in significantly impaired fracture healing. Fragility, or osteoporotic, fractures represent a major medical problem as they are associated with permanent disability and premature death. Using a murine model of fragility fractures, we found that local rhTNF treatment improved fracture healing during the early phase of repair. If translated clinically, this promotion of fracture healing would reduce the morbidity and mortality associated with delayed patient mobilization. © 2015 The Authors. Published under the terms of the CC BY 4.0 license.

An evaluation of flexible intramedullary nail fixation in femoral shaft fractures in paediatric age group.

PubMed

Kumar, Sanjay; Roy, Sandip Kumar; Jha, Amrish Kumar; Chatterjee, Debdutta; Banerjee, Debabrata; Garg, Anant Kumar

2011-06-01

Sixty-two femoral shaft fractures in 60 patients treated by elastic intramedullary nailing with mean age of the patients being 9.2 years (range 5 years to 12 years) and average follow-up of 15 months (range 7 months to 60 months) are evaluated. Twenty-eight fractures were fixed with titanium elastic nail while 34 fractures were fixed with Enders nail. There were 40 midshaft fractures, 18 proximal femoral and 4 were fractures of distal third. Fracture patterns were transverse in 35, short oblique in 14 cases and 13 were spiral fractures. Mean age of union in this series was 17 weeks (range 12 weeks to 28 weeks). Ten cases had complications, 5 had nail tip irritation, 3 varus or valgus malalignment and 2 had delayed union. In this series, we did not have any non-union, refracture, limb length discrepancy or any major infection. The result demonstrates 100% union rate irrespective of the age, weight and height of the patient. Regardless of the site of fracture and their pattern, it united every time with elastic nail fixation. We did not find and mismatch in the results of fractures stabilised with titanium elastic nail with that of elastic stainless steel nail.

Complications and Functional Recovery in Treatment of Femoral Shaft Fractures with Unreamed Intramedullary Nailing

PubMed Central

Sadic, Sahmir; Custovic, Svemir; Smajic, Nedim; Fazlic, Mirsad; Vujadinovic, Aleksandar; Hrustic, Asmir; Jasarevic, Mahir

2014-01-01

ABSTRACT Introduction: Fracture of the femoral shaft is a common fracture encountered in orthopedic practice. In the 1939, Küntscher introduced the concept of intramedullary nailing for stabilization of long bone fractures. Intramedullary nailing has revolutionized the treatment of fractures. Material and methods: The study included 37 male patients and 13 female patients, averaged 39±20,5 years (range, 16 to 76 years). Results and discussion: There were 31 left femurs and 21 right femurs fractured. 46 fractures were the result of blunt trauma. Low energy trauma was the cause of fractures in six patients, of which five in elderly females. 49 fractures were closed. Healing time given in weeks was 19,36 ± 6,1. The overall healing rate was 93,6%. There were three (6,25%) major complications nonunion. There were one (2%) delayed union, one (2%) rotational malunion and no infection. The shortening of 1 cm were in two patients. Antercurvatum of 10 degrees was found in one patient. There was no statistically significant reduction of a motion in the hip and knee (p<0.05). There was statistically significant in the thigh (knee extensors) muscle weakness (p<0.001). Conclusion: Intramedullary nailing is the treatment of choice for femoral shaft fractures. PMID:24783908

Bone morphogenetic protein 2 and decorin expression in old fracture fragments and surrounding tissues.

PubMed

Han, X G; Wang, D K; Gao, F; Liu, R H; Bi, Z G

2015-09-21

Bone morphogenetic protein 2 (BMP-2) can promote fracture healing. Although the complex role BMP-2 in bone formation is increasingly understood, the role of endogenous BMP-2 in nonunion remains unclear. Decorin (DCN) can promote the formation of bone matrix and calcium deposition to control bone morphogenesis. In this study, tissue composition and expression of BMP-2 and DCN were detected in different parts of old fracture zones to explore inherent anti-fibrotic ability and osteogenesis. Twenty-three patients were selected, including eight cases of delayed union and 15 cases of nonunion. Average duration of delayed union or nonunion was 15 months. Fracture fragments and surrounding tissues, including bone grafts, marrow cavity contents, and sticking scars, were categorically sampled during surgery. Through observation and histological testing, component comparisons were made between fracture fragments and surrounding tissue. The expression levels of DCN and BMP-2 in different tissues were detected by immunohistochemical staining and real-time polymerase chain reaction. The expression of DCN and BMP- 2 in different parts of the nonunion area showed that, compared with bone graft and marrow cavity contents, sticking scars had the highest expression of BMP-2. Compared with the marrow cavity contents and sticking scars, bone grafts had the highest expression of DCN. The low antifibrotic and osteogenic activity of the nonunion area was associated with non-co-expression of BMP-2 and DCN. Therefore, the co-injection of osteogenic factor BMP and DCN into the nonunion area can improve the induction of bone formation and enhance the conversion of the old scar, thereby achieving better nonunion treatment.

What is the hardware removal rate after anteroinferior plating of the clavicle? A retrospective cohort study.

PubMed

Baltes, Thomas P A; Donders, Johanna C E; Kloen, Peter

2017-10-01

Plate position in the operative treatment of displaced midshaft clavicle fractures or nonunions is most often on the superior side. However, superior clavicular plating often results in complaints of plate prominence and local soft tissue irritation, necessitating hardware removal. We have used anteroinferior placement of the plate in the hope of increasing biomechanical stability and fixation and also of lowering complaints of plate prominence and soft tissue irritation. In this report, we set out to study the percentage of hardware removal in our group of patients treated with anteroinferior plating of the clavicle after long-term follow-up. In this retrospective review, we evaluated all patients who were surgically treated with anteroinferior plating for midshaft clavicle fracture, delayed union, or nonunion by the senior author between February 2003 and July 2015. Patients required a minimum age of 16 years at time of surgery and a follow-up of >12 months. Patients with malunion, plating on the superior aspect, or double plating were excluded. The medical records of 53 patients (54 fractures) were reviewed after a mean follow-up duration of 6.4 years (range, 1.1-13.1). The mean age at follow-up was 47.8 years (range, 20.4-80.7). All fractures and nonunions healed. In only 3 cases (5.6%), hardware removal was requested by the patient because of plate prominence. Anteroinferior plating of midshaft clavicle fractures, delayed unions, and nonunions resulted in low hardware removal rates in our cohort. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Influence of fracture network physical properties on stability criteria of density-driven flow in a dual-porosity system

NASA Astrophysics Data System (ADS)

Hassanzadeh, H.; Jafari Raad, S. M.

2017-12-01

Linear stability analysis is conducted to study the onset of buoyancy-driven convection involved in solubility trapping of CO2 into deep fractured aquifers. In this study, the effect of fracture network physical properties on the stability criteria in a brine-rich fractured porous layer is investigated using dual porosity concept for both single and variable matrix block size distributions. Linear stability analysis results show that both fracture interporosity flow and fracture storativity factors play an important role in the stability behavior of the system. It is shown that a diffusive boundary layer under the gravity field in a fractured rock with lower fracture storativity and/or higher fracture interporosity flow coefficient is more stable. We present scaling relations that relate the onset of convective instability in fractured aquifers. These findings improve our understanding of buoyancy driven flow in fractured aquifers and are particularly important in estimation of potential storage capacity, risk assessment, and storage sites characterization and screening.Keywords: CO2 sequestration; fractured rock; buoyancy-driven convection; stability analysis

A NOVEL APPROACH TO TREATMENT FOR CHRONIC AVULSION FRACTURE OF THE ISCHIAL TUBEROSITY IN THREE ADOLESCENT ATHLETES: A CASE SERIES

PubMed Central

Nilsson, Kurt J.

2014-01-01

Background and Incidence: Ischial tuberosity fracture and its associated complications are an under recognized diagnosis in the adolescent athlete. Apophyseal injuries of the pelvis in the skeletally immature athlete can occur in multiple locations but are most common at the ischial tuberosity, affecting males more commonly than females. Description of Injury and Current Management: The most common cause of ischial tuberosity avulsion fracture is a quick eccentric load to the proximal hamstrings, occurring with kicking as in soccer, football, or dance. Signs and symptoms are similar to a proximal hamstring injury but avulsion injuries often go undiagnosed, as radiographs are not frequently obtained. In acute cases, rest and relative immobilization are the recommended course of care. In chronic cases, including those with delayed diagnosis, or those that remain symptomatic after initial care due to non‐union or associated sciatic nerve adhesions, surgery is often performed in order to restore normal anatomy, alleviate symptoms, and help return the athlete to full activity. Purpose: The authors' share a novel treatment approach consisting of ultrasound guided percutaneous needle fenestration for the treatment of three adolescent athletes with symptomatic delayed diagnoses of ischial tuberosity fractures. Needle fenestration was followed by a physical therapy progression which was developed based on tissue healing rates, symptom presentation, and the available literature related to proximal hamstring injuries. Outcomes: Two athletes reported elimination of pain, full functional recovery and return to sport without limitations as measured by use of the Numeric Pain Rating Scale, the Global Rating of Change Scale, and the Lower Extremity Functional Scale. One athlete reported elimination of pain and full functional recovery and chose to return to a new sport. Symptoms of possible concurrent hamstring syndrome are discussed as well the management of this condition. Discussion/Conclusions: This case series introduced a novel approach for treatment of symptomatic delayed union ischial tuberosity fractures in three adolescents prior to consideration of surgical intervention. Percutanous needle fenestration and the described subsequent rehabilitation provided positive treatment outcomes in the presented cases, including full return to athletic and recreational endeavors. Level of Evidence: Level 5 PMID:25540712

Prediction of Fracture Behavior in Rock and Rock-like Materials Using Discrete Element Models

NASA Astrophysics Data System (ADS)

Katsaga, T.; Young, P.

2009-05-01

The study of fracture initiation and propagation in heterogeneous materials such as rock and rock-like materials are of principal interest in the field of rock mechanics and rock engineering. It is crucial to study and investigate failure prediction and safety measures in civil and mining structures. Our work offers a practical approach to predict fracture behaviour using discrete element models. In this approach, the microstructures of materials are presented through the combination of clusters of bonded particles with different inter-cluster particle and bond properties, and intra-cluster bond properties. The geometry of clusters is transferred from information available from thin sections, computed tomography (CT) images and other visual presentation of the modeled material using customized AutoCAD built-in dialog- based Visual Basic Application. Exact microstructures of the tested sample, including fractures, faults, inclusions and void spaces can be duplicated in the discrete element models. Although the microstructural fabrics of rocks and rock-like structures may have different scale, fracture formation and propagation through these materials are alike and will follow similar mechanics. Synthetic material provides an excellent condition for validating the modelling approaches, as fracture behaviours are known with the well-defined composite's properties. Calibration of the macro-properties of matrix material and inclusions (aggregates), were followed with the overall mechanical material responses calibration by adjusting the interfacial properties. The discrete element model predicted similar fracture propagation features and path as that of the real sample material. The path of the fractures and matrix-inclusion interaction was compared using computed tomography images. Initiation and fracture formation in the model and real material were compared using Acoustic Emission data. Analysing the temporal and spatial evolution of AE events, collected during the sample testing, in relation to the CT images allows the precise reconstruction of the failure sequence. Our proposed modelling approach illustrates realistic fracture formation and growth predictions at different loading conditions.

Three-Dimensional Smoothed Particle Hydrodynamics Modeling of Preferential Flow Dynamics at Fracture Intersections on a High-Performance Computing Platform

NASA Astrophysics Data System (ADS)

Kordilla, J.; Bresinsky, L. T.

2017-12-01

The physical mechanisms that govern preferential flow dynamics in unsaturated fractured rock formations are complex and not well understood. Fracture intersections may act as an integrator of unsaturated flow, leading to temporal delay, intermittent flow and partitioning dynamics. In this work, a three-dimensional Pairwise-Force Smoothed Particle Hydrodynamics (PF-SPH) model is being applied in order to simulate gravity-driven multiphase flow at synthetic fracture intersections. SPH, as a meshless Lagrangian method, is particularly suitable for modeling deformable interfaces, such as three-phase contact dynamics of droplets, rivulets and free-surface films. The static and dynamic contact angle can be recognized as the most important parameter of gravity-driven free-surface flow. In SPH, surface tension and adhesion naturally emerges from the implemented pairwise fluid-fluid (sff) and solid-fluid (ssf) interaction force. The model was calibrated to a contact angle of 65°, which corresponds to the wetting properties of water on Poly(methyl methacrylate). The accuracy of the SPH simulations were validated against an analytical solution of Poiseuille flow between two parallel plates and against laboratory experiments. Using the SPH model, the complex flow mode transitions from droplet to rivulet flow of an experimental study were reproduced. Additionally, laboratory dimensionless scaling experiments of water droplets were successfully replicated in SPH. Finally, SPH simulations were used to investigate the partitioning dynamics of single droplets into synthetic horizontal fractures with various apertures (Δdf = 0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0 mm) and offsets (Δdoff = -1.5, -1.0, -0.5, 0, 1.0, 2.0, 3.0 mm). Fluid masses were measured in the domains R1, R2 and R3. The perfect conditions of ideally smooth surfaces and the SPH inherent advantage of particle tracking allow the recognition of small scale partitioning mechanisms and its importance for bulk flow behavior.

Physical simulation study on the hydraulic fracture propagation of coalbed methane well

NASA Astrophysics Data System (ADS)

Wu, Caifang; Zhang, Xiaoyang; Wang, Meng; Zhou, Longgang; Jiang, Wei

2018-03-01

As the most widely used technique to modify reservoirs in the exploitation of unconventional natural gas, hydraulic fracturing could effectively raise the production of CBM wells. To study the propagation rules of hydraulic fractures, analyze the fracture morphology, and obtain the controlling factors, a physical simulation experiment was conducted with a tri-axial hydraulic fracturing test system. In this experiment, the fracturing sample - including the roof, the floor, and the surrounding rock - was prepared from coal and similar materials, and the whole fracturing process was monitored by an acoustic emission instrument. The results demonstrated that the number of hydraulic fractures in coal is considerably higher than that observed in other parts, and the fracture morphology was complex. Vertical fractures were interwoven with horizontal fractures, forming a connected network. With the injection of fracturing fluid, a new hydraulic fracture was produced and it extended along the preexisting fractures. The fracture propagation was a discontinuous, dynamic process. Furthermore, in-situ stress plays a key role in fracture propagation, causing the fractures to extend in a direction perpendicular to the minimum principal stress. To a certain extent, the different mechanical properties of the coal and the other components inhibited the vertical propagation of hydraulic fractures. Nonetheless, the vertical stress and the interfacial property are the major factors to influence the formation of the "T" shaped and "工" shaped fractures.

Effect of heat-treatment conditions on the structure and physicomechanical and chemical properties of a Ni-Cr-Cu-Ti maraging steel

NASA Astrophysics Data System (ADS)

Bannykh, O. A.; Berezovskaya, V. V.

2007-06-01

The effects of quenching (from 950°C or from 950 and 850°C) and the aging conditions on the structure, properties, and delayed fracture (DF) of 03Kh11N10M2DT maraging steel has been studied by dilatometry, X-ray diffraction, and fracture tests. The DF-crack growth rate is maximal after aging at 400°C irrespective of the quenching conditions, and the corrosion rate is maximal after aging at 350 400°C in the case of single quenching and at 350°C after double quenching. The kinetics and mechanism of the early stages of the decomposition of a supersaturated α solid solution are investigated by electrical-resistance measurements and transmission electron microscopy. In the state after single quenching, aging occurs in two stages at all isothermal heat treatments; in the state after double quenching, aging occurs in one stage at a time exponent n = 0.2 in the Johnson-Mehl equation. Upon aging at 400°C, the intermediate ordered Fe3(Ni,Ti) phase with a complex cubic lattice precipitates, and the intermetallic compound Ni3Ti precipitates upon subsequent aging. Moreover, copper-rich ɛ-phase precipitates form only in the case of single quenching. The substantial increase in the crack growth rate during DF with n < 0.2 is likely to be caused by the formation of Guinier-Preston zones enriched in nickel and titanium.

Association of maternal fractures with adverse perinatal outcomes.

PubMed

El Kady, Dina; Gilbert, William M; Xing, Guibo; Smith, Lloyd H

2006-09-01

We sought to assess the effects of fracture injuries on maternal and fetal/neonatal outcomes in a large obstetric population. We performed a retrospective cohort study using a database in which maternal and neonatal hospital discharge summaries were linked with birth and death certificates to identify any relation between maternal fractures and maternal and perinatal morbidity. Fracture injuries and perinatal outcomes were identified with the use of the International Classification of Diseases, 9th revision, Clinical Modification codes. Outcomes were further subdivided on the basis of anatomic site of fracture. A total of 3292 women with > or = 1 fractures were identified. Maternal mortality (odds ratio, 169 [95% CI, 83.2,346.4]) and morbidity (abruption and blood transfusion) rates were increased significantly in women who were delivered during hospitalization for their injury. Women who were discharged undelivered continued to have delayed morbidity, which included a 46% increased risk of low birth weight infants (odds ratio, 1.5 [95% CI, 1.3,1.7]) and a 9-fold increased risk of thrombotic events (odds ratio, 9.2 [95% CI, 1.3,65.7]) Pelvic fractures had the worst outcomes. Fractures during pregnancy are an important marker for poor perinatal outcomes.

Challenges and Solutions for the Integration of Structural and Hydrogeological Understanding of Fracture Systems - Insights from the Olkiluoto Site, Finland

NASA Astrophysics Data System (ADS)

Hartley, L. J.; Aaltonen, I.; Baxter, S. J.; Cottrell, M.; Fox, A. L.; Hoek, J.; Koskinen, L.; Mattila, J.; Mosley, K.; Selroos, J. O.; Suikkanen, J.; Vanhanarkaus, O.; Williams, T. R. N.

2017-12-01

A field site at Olkiluoto in SW Finland has undergone extensive investigations as a location for a deep geological repository for spent nuclear fuel, which is expected to become operational in the early 2020s. Characterisation data comes from 58 deep cored drillholes, a wide variety of geophysical investigations, many outcrops, kilometres of underground mapping and testing in the ONKALO research facility, and groundwater pressure monitoring and sampling in both deep and shallow holes. A primary focus is on the properties of natural fractures and brittle fault zones in the low permeability crystalline rocks at Olkiluoto; an understanding of the flow and transport processes in these features are an essential part of assessing long-term safety of the repository. This presentation will illustrate how different types of source data and cross-disciplinary interpretations are integrated to develop conceptual and numerical models of the fracture system. A model of the brittle fault zones developed from geological and geophysical data provides the hydrostructural backbone controlling the most intense fracturing and dynamic conduits for fluids. Models of ductile deformation and lithology form a tectonic framework for the description of fracture heterogeneity in the background rock, revealing correlations between the intensity and orientation of fractures with geological and spatial properties. The sizes of brittle features are found to be best defined on two scales relating to individual fractures and zones. Inferred fracture-specific from flow logging are correlated with fracture geometric and mechanical properties along with in situ stress measurements to create a hydromechanical description of fracture hydraulic properties. The insights and understandings gained from these efforts help define a discrete fracture network (DFN) model for the Olkiluoto site, with hydrogeological characteristics consistent with monitoring data of hydraulic heads and their disturbances to pumping and underground construction. This work offers ideas and proposed solutions on how some of the challenges in describing fractured rock hydrogeology can be tackled.

A comparative study of discrete fracture network and equivalent continuum models for simulating flow and transport in the far field of a hypothetical nuclear waste repository in crystalline host rock

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hadgu, Teklu; Karra, Satish; Kalinina, Elena

One of the major challenges of simulating flow and transport in the far field of a geologic repository in crystalline host rock is related to reproducing the properties of the fracture network over the large volume of rock with sparse fracture characterization data. Various approaches have been developed to simulate flow and transport through the fractured rock. The approaches can be broadly divided into Discrete Fracture Network (DFN) and Equivalent Continuum Model (ECM). The DFN explicitly represents individual fractures, while the ECM uses fracture properties to determine equivalent continuum parameters. In this paper, we compare DFN and ECM in termsmore » of upscaled observed transport properties through generic fracture networks. The major effort was directed on making the DFN and ECM approaches similar in their conceptual representations. This allows for separating differences related to the interpretation of the test conditions and parameters from the differences between the DFN and ECM approaches. The two models are compared using a benchmark test problem that is constructed to represent the far field (1 × 1 × 1 km 3) of a hypothetical repository in fractured crystalline rock. The test problem setting uses generic fracture properties that can be expected in crystalline rocks. The models are compared in terms of the: 1) effective permeability of the domain, and 2) nonreactive solute breakthrough curves through the domain. The principal differences between the models are mesh size, network connectivity, matrix diffusion and anisotropy. We demonstrate how these differences affect the flow and transport. Finally, we identify the factors that should be taken in consideration when selecting an approach most suitable for the site-specific conditions.« less

A comparative study of discrete fracture network and equivalent continuum models for simulating flow and transport in the far field of a hypothetical nuclear waste repository in crystalline host rock

DOE PAGES

Hadgu, Teklu; Karra, Satish; Kalinina, Elena; ...

2017-07-28

One of the major challenges of simulating flow and transport in the far field of a geologic repository in crystalline host rock is related to reproducing the properties of the fracture network over the large volume of rock with sparse fracture characterization data. Various approaches have been developed to simulate flow and transport through the fractured rock. The approaches can be broadly divided into Discrete Fracture Network (DFN) and Equivalent Continuum Model (ECM). The DFN explicitly represents individual fractures, while the ECM uses fracture properties to determine equivalent continuum parameters. In this paper, we compare DFN and ECM in termsmore » of upscaled observed transport properties through generic fracture networks. The major effort was directed on making the DFN and ECM approaches similar in their conceptual representations. This allows for separating differences related to the interpretation of the test conditions and parameters from the differences between the DFN and ECM approaches. The two models are compared using a benchmark test problem that is constructed to represent the far field (1 × 1 × 1 km 3) of a hypothetical repository in fractured crystalline rock. The test problem setting uses generic fracture properties that can be expected in crystalline rocks. The models are compared in terms of the: 1) effective permeability of the domain, and 2) nonreactive solute breakthrough curves through the domain. The principal differences between the models are mesh size, network connectivity, matrix diffusion and anisotropy. We demonstrate how these differences affect the flow and transport. Finally, we identify the factors that should be taken in consideration when selecting an approach most suitable for the site-specific conditions.« less

A comparative study of discrete fracture network and equivalent continuum models for simulating flow and transport in the far field of a hypothetical nuclear waste repository in crystalline host rock

NASA Astrophysics Data System (ADS)

Hadgu, Teklu; Karra, Satish; Kalinina, Elena; Makedonska, Nataliia; Hyman, Jeffrey D.; Klise, Katherine; Viswanathan, Hari S.; Wang, Yifeng

2017-10-01

One of the major challenges of simulating flow and transport in the far field of a geologic repository in crystalline host rock is related to reproducing the properties of the fracture network over the large volume of rock with sparse fracture characterization data. Various approaches have been developed to simulate flow and transport through the fractured rock. The approaches can be broadly divided into Discrete Fracture Network (DFN) and Equivalent Continuum Model (ECM). The DFN explicitly represents individual fractures, while the ECM uses fracture properties to determine equivalent continuum parameters. We compare DFN and ECM in terms of upscaled observed transport properties through generic fracture networks. The major effort was directed on making the DFN and ECM approaches similar in their conceptual representations. This allows for separating differences related to the interpretation of the test conditions and parameters from the differences between the DFN and ECM approaches. The two models are compared using a benchmark test problem that is constructed to represent the far field (1 × 1 × 1 km3) of a hypothetical repository in fractured crystalline rock. The test problem setting uses generic fracture properties that can be expected in crystalline rocks. The models are compared in terms of the: 1) effective permeability of the domain, and 2) nonreactive solute breakthrough curves through the domain. The principal differences between the models are mesh size, network connectivity, matrix diffusion and anisotropy. We demonstrate how these differences affect the flow and transport. We identify the factors that should be taken in consideration when selecting an approach most suitable for the site-specific conditions.

Non-Newtonian fluid flow in 2D fracture networks

NASA Astrophysics Data System (ADS)

Zou, L.; Håkansson, U.; Cvetkovic, V.

2017-12-01

Modeling of non-Newtonian fluid (e.g., drilling fluids and cement grouts) flow in fractured rocks is of interest in many geophysical and industrial practices, such as drilling operations, enhanced oil recovery and rock grouting. In fractured rock masses, the flow paths are dominated by fractures, which are often represented as discrete fracture networks (DFN). In the literature, many studies have been devoted to Newtonian fluid (e.g., groundwater) flow in fractured rock using the DFN concept, but few works are dedicated to non-Newtonian fluids.In this study, a generalized flow equation for common non-Newtonian fluids (such as Bingham, power-law and Herschel-Bulkley) in a single fracture is obtained from the analytical solutions for non-Newtonian fluid discharge between smooth parallel plates. Using Monte Carlo sampling based on site characterization data for the distribution of geometrical features (e.g., density, length, aperture and orientations) in crystalline fractured rock, a two dimensional (2D) DFN model is constructed for generic flow simulations. Due to complex properties of non-Newtonian fluids, the relationship between fluid discharge and the pressure gradient is nonlinear. A Galerkin finite element method solver is developed to iteratively solve the obtained nonlinear governing equations for the 2D DFN model. Using DFN realizations, simulation results for different geometrical distributions of the fracture network and different non-Newtonian fluid properties are presented to illustrate the spatial discharge distributions. The impact of geometrical structures and the fluid properties on the non-Newtonian fluid flow in 2D DFN is examined statistically. The results generally show that modeling non-Newtonian fluid flow in fractured rock as a DFN is feasible, and that the discharge distribution may be significantly affected by the geometrical structures as well as by the fluid constitutive properties.

Inverse modeling of the hydraulic properties of fractured media : development of a flow tomography approach

NASA Astrophysics Data System (ADS)

Bour, O.; Klepikova, M.; Le Borgne, T.; De Dreuzy, J.

2013-12-01

Inverse modeling of hydraulic and geometrical properties of fractured media is a very challenging objective due to the spatial heterogeneity of the medium and the scarcity of data. Here we present a flow tomography approach that permits to characterize the location, the connectivity and the hydraulic properties of main flow paths in fractured media. The accurate characterization of the location, hydraulic properties and connectivity of major fracture zones is essential to model flow and solute transport in fractured media. Cross-borehole flowmeter tests, which consist of measuring changes in vertical borehole flows when pumping a neighboring borehole, were shown to be an efficient technique to provide information on the properties of the flow zones that connect borehole pairs [Paillet, 1998; Le Borgne et al., 2006]. The interpretation of such experiments may however be quite uncertain when multiple connections exist. In this study, we explore the potential of flow tomography (i.e., sequential cross-borehole flowmeter tests) for characterizing aquifer heterogeneity. We first propose a framework for inverting flow and drawdown data to infer fracture connectivity and transmissivities. Here we use a simplified discrete fracture network approach that highlights main connectivity structures. This conceptual model attempts to reproduce fracture network connectivity without taking fracture geometry (length, orientation, dip) into account. We then explore the potential of the method for simplified synthetic fracture network models and quantify the sensitivity of drawdown and borehole flow velocities to the transmissivity of the connecting flowpaths. Flow tomography is expected to be most effective if cross-borehole pumping induces large changes in vertical borehole velocities. The uncertainty of the transmissivity estimates increases for small borehole flow velocities. The uncertainty about the transmissivity of fractures that connect the main flowpath but not the boreholes is generally higher. We demonstrate that successively changing pumping and observation boreholes improves the quality of available information and reduces the indetermination of the problem. The inverse method is validated for different synthetic flow scenarios. It is shown to provide a good estimation of connectivity patterns and transmissivities of main flowpaths. Although the chosen fracture network geometry has been simplified, flow tomography appears to be a promising approach for characterizing connectivity patterns and transmissivities of fractured media.

Increase of Coastal Cliff Rockfall Trigerred By Rainfall On The Chalk Coast of NW France During The Year 2001

NASA Astrophysics Data System (ADS)

Duperret, A.; Genter, A.; Daigneault, M.; Mortimore, R. N.

Coastal chalk cliffs exposed on each part of the English Channel suffer numerous collapses, with mean volumes varying between 10 000 and 100 000 cubic meters. Between October 1998 and October 2001, a minimum of 52 collapses have been ob- served along 120 km of the French chalk coastline located in Upper-Normandy and Picardy. The chalk coastline has evidenced 4 collapses in 1999 and 6 collapses in 2000 (winter and spring), whereas 28 collapses with volume greater than 1000 m3 was recorded in 2001 (winter, spring and summer). The increase of large-scale collapses during 2001 is interpreted as an excess of rainfalls recorded previously. Most of these collapses extend all over the vertical cliff height and are mainly controlled by ground- water infiltration. The modality of water circulation through the chalk rock depends on the chalk lithology and the hydrogeological properties of pre-existing fractures. In the framework of the European scientific project named ROCC (Risk of Cliff Col- lapse), the chalk lithology and the pre-existing fracture pattern have been investigated in order to determine the response of the rock mass to subaerial and marine solicita- tions, including rainfall conditions. Such data have been reported in a GIS system in order to determine the degree of cliff sensibility to collapses. Some rainfall-triggered collapses will be presented to illustrate the diversity of the rock mass response to rain- fall excess, in terms of rock mass characteristics and time delay: (1) a collapse was witnessed at Puys, the 17th May 2000, after two periods of intense rainfall inducing floods, during the two previous months. The occurrence of impervious marl seams levels within the chalk and its low fracture content may have generated water over- pressure and consequently stress concentration on the marl seams, which conduct to the rupture. The delay between rainfall and the rupture may be explained by the low velocity of groundwater through a poorly fractured porous chalk. (2) a series of large- scale collapses has been evidenced at Yport in June 2001, at Grandes Dalles the 15th July 2001 and at Benouville the 24th July 2001. These collapses occurred after a dry period, during the previous three months. A collapse occurred again at Yport the 27th August 2001, after an increase of rainfall during August 2001. All these sites present the same lithological chalk succession than at Puys, but their fracture pattern is made of large-scale subvertical fractures expanding all over the cliff height. Some of them 1 which correspond to dissolution pipes are filled with clays-with-flints. The sharp in- crease of collapses during the summer 2001 could be related to the superimposition of dry periods which alternate with heavy rainfalls, in karst environment. 2

Numerical Modelling of Femur Fracture and Experimental Validation Using Bone Simulant.

PubMed

Marco, Miguel; Giner, Eugenio; Larraínzar-Garijo, Ricardo; Caeiro, José Ramón; Miguélez, María Henar

2017-10-01

Bone fracture pattern prediction is still a challenge and an active field of research. The main goal of this article is to present a combined methodology (experimental and numerical) for femur fracture onset analysis. Experimental work includes the characterization of the mechanical properties and fracture testing on a bone simulant. The numerical work focuses on the development of a model whose material properties are provided by the characterization tests. The fracture location and the early stages of the crack propagation are modelled using the extended finite element method and the model is validated by fracture tests developed in the experimental work. It is shown that the accuracy of the numerical results strongly depends on a proper bone behaviour characterization.

Torsional and axial compressive properties of tibiotarsal bones of red-tailed hawks (Buteo jamaicensis).

PubMed

Kerrigan, Shannon M; Kapatkin, Amy S; Garcia, Tanya C; Robinson, Duane A; Guzman, David Sanchez-Migallon; Stover, Susan M

2018-04-01

OBJECTIVE To describe the torsional and axial compressive properties of tibiotarsal bones of red-tailed hawks (Buteo jamaicensis). SAMPLE 16 cadaveric tibiotarsal bones from 8 red-tailed hawks. PROCEDURES 1 tibiotarsal bone from each bird was randomly assigned to be tested in torsion, and the contralateral bone was tested in axial compression. Intact bones were monotonically loaded in either torsion (n = 8) or axial compression (8) to failure. Mechanical variables were derived from load-deformation curves. Fracture configurations were described. Effects of sex, limb side, and bone dimensions on mechanical properties were assessed with a mixed-model ANOVA. Correlations between equivalent torsional and compressive properties were determined. RESULTS Limb side and bone dimensions were not associated with any mechanical property. During compression tests, mean ultimate cumulative energy and postyield energy for female bones were significantly greater than those for male bones. All 8 bones developed a spiral diaphyseal fracture and a metaphyseal fissure or fracture during torsional tests. During compression tests, all bones developed a crushed metaphysis and a fissure or comminuted fracture of the diaphysis. Positive correlations were apparent between most yield and ultimate torsional and compressive properties. CONCLUSIONS AND CLINICAL RELEVANCE The torsional and axial compressive properties of tibiotarsal bones described in this study can be used as a reference for investigations into fixation methods for tibiotarsal fractures in red-tailed hawks. Although the comminuted and spiral diaphyseal fractures induced in this study were consistent with those observed in clinical practice, the metaphyseal disruption observed was not and warrants further research.

The clinical presentation and management of zygomatic complex fractures in a Nigeria Teaching Hospital.

PubMed

Anyanechi, C E; Charles, E A; Saheeb, B D; Birch, D S

2012-01-01

Fractures of the zygomatic complex occur worldwide and are a component part of injuries that can be sustained in the maxillofacial region. The objective was to analyze the clinical presentation and management ofzygomatic complex fractures. This was a prospective study carried out over a period of five years at the University of Calabar Teaching Hospital, Nigeria. Data documented were patients' age, gender, time of presentation, cause and type of fracture, associated head and maxillofacial injuries, clinical features, types of plain radiographs, treatment methods, duration of follow-up and complications. Majority of the patients (n = 81, 63.3%) were in their third and fourth decades of life while the male to female ratio was 20.3:1. Road traffic accident (n = 111, 86.7%) was the most common cause of fracture. Fractures of the zygomatic complex alone (n = 105, 82.0%) were more common than isolated fractures of the arch (n = 13, 10.2%) and combined fractures of the zygomatic complex and arch (n = 10, 7.8%). While multi-disciplinary approach to treatment is important, majority of the fractures were treated by simple elevation and transosseous wire osteosynthesis. Delay in presentation, associated injuries and non-availability of mini-plating technique contributed to the development of complications.

Outcome of intramedullary interlocking SIGN nail in tibial diaphyseal fracture.

PubMed

Khan, Irfanullah; Javed, Shahzad; Khan, Gauhar Nawaz; Aziz, Amer

2013-03-01

To determine the outcome of intramedullary interlocking surgical implant generation network (SIGN) nail in diaphyseal tibial fractures in terms of union and failure of implant (breakage of nail or interlocking screws). Case series. Orthopaedics and Spinal Surgery, Ghurki Trust Teaching Hospital, Lahore Medical and Dental College, Lahore, from September 2008 to August 2009. Fifty patients aged 14 - 60 years, of either gender were included, who had closed and Gustilo type I and II open fractures reported in 2 weeks, whose closed reduction was not possible or was unsatisfactory and fracture was located 7 cm below knee joint to 7 cm above ankle joint. Fractures previously treated with external fixator, infected fractures and unfit patients were excluded. All fractures were fixed with intramedullary interlocking SIGN nail and were followed clinically and radiographically for union and for any implant failure. Forty one (88%) patients had united fracture within 6 months, 5 (10%) patients had delayed union while 4 (8%) patients had non-union. Mean duration for achieving union was 163 + 30.6 days. Interlocking screws were broken in 2 patients while no nail was broken in any patient. Intramedullary interlocking nailing is an effective measure in treating closed and grade I and II open tibial fractures. It provides a high rate of union less complications and early return to function.

Injuries and Physical Fitness Before and After Deployments of the 10th Mountain Division to Afghanistan and the 1st Cavalry Division to Iraq, September 2005 - October 2008

DTIC Science & Technology

2008-10-01

Epidemiology Report No. 12-HF-05SR-05, September 2005 – October 2008 5 especially for fractures and for bone and soft-tissue injuries, in two...more in-theater hospitalizations,(22, 23) so that service members required less “ delayed ” postdeployment hospitalization. (6) Postdeployment...lower body overuse-type injuries and includes diagnoses such as stress fractures , stress reactions, tendonitis, bursitis, fasciitis, arthralgia

Radionuclide Imaging of Musculoskeletal Injuries in Athletes with Negative Radiographs.

PubMed

Nagle, C E; Freitas, J E

1987-06-01

In brief: Radionuclide bone scans can be useful in the diagnostic evaluation of musculoskeletal injuries in athletes. Bone scans can detect shinsplints, stress fractures, and muscle injuries before they are detectable on radiographs. Prognosis can be accurately assessed, allowing appropriate treatment to proceed without delay. The authors discuss the use of bone scans and identify musculoskeletal injuries that are associated with specific sports, such as stress fracture of the femur (soccer), tibia (running), scapula (gymnastics), and pars interarticularis (football or lacrosse).

Hydraulic Properties of Closely Spaced Dipping Open Fractures Intersecting a Fluid-Filled Borehole Derived From Tube Wave Generation and Scattering

NASA Astrophysics Data System (ADS)

Minato, Shohei; Ghose, Ranajit; Tsuji, Takeshi; Ikeda, Michiharu; Onishi, Kozo

2017-10-01

Fluid-filled fractures and fissures often determine the pathways and volume of fluid movement. They are critically important in crustal seismology and in the exploration of geothermal and hydrocarbon reservoirs. We introduce a model for tube wave scattering and generation at dipping, parallel-wall fractures intersecting a fluid-filled borehole. A new equation reveals the interaction of tube wavefield with multiple, closely spaced fractures, showing that the fracture dip significantly affects the tube waves. Numerical modeling demonstrates the possibility of imaging these fractures using a focusing analysis. The focused traces correspond well with the known fracture density, aperture, and dip angles. Testing the method on a VSP data set obtained at a fault-damaged zone in the Median Tectonic Line, Japan, presents evidences of tube waves being generated and scattered at open fractures and thin cataclasite layers. This finding leads to a new possibility for imaging, characterizing, and monitoring in situ hydraulic properties of dipping fractures using the tube wavefield.

Investigation of Mechanical Properties and Fracture Simulation of Solution-Treated AA 5754

NASA Astrophysics Data System (ADS)

Kumar, Pankaj; Singh, Akhilendra

2017-10-01

In this work, mechanical properties and fracture toughness of as-received and solution-treated aluminum alloy 5754 (AA 5754) are experimentally evaluated. Solution heat treatment of the alloy is performed at 530 °C for 2 h, and then, quenching is done in water. Yield strength, ultimate tensile strength, impact toughness, hardness, fatigue life, brittle fracture toughness (K_{Ic} ) and ductile fracture toughness (J_{Ic} ) are evaluated for as-received and solution-treated alloy. Extended finite element method has been used for the simulation of tensile and fracture behavior of material. Heaviside function and asymptotic crack tip enrichment functions are used for modelling of the crack in the geometry. Ramberg-Osgood material model coupled with fracture energy is used to simulate the crack propagation. Fracture surfaces obtained from various mechanical tests are characterized by scanning electron microscopy.

The relative stress-corrosion-cracking susceptibility of candidate aluminum-lithium alloys for aerospace structural applications

NASA Technical Reports Server (NTRS)

Pizzo, P. P.

1980-01-01

The microstructure and tensile properties of two powder metallurgy processed aluminum-lithium alloys were determined. Strength properties of 480 MPa yield and 550 MPa ultimate tensile strength with 5% strain to fracture were attained. Very little reduction in area was observed and fracture characteristics were brittle. The magnesium bearing alloy exhibited the highest strength and ductility, but fracture was intergranular. Recrystallization and grain growth, as well as coarse grain boundary precipitation, occurred in Alloy 2. The fracture morphology of the two alloys differed. Alloy 1 fractured along a plane of maximum shear stress, while Alloy 2 fractured along a plane of maximum tensile stress. It is found that a fixed orientation relationship exists between the shear fracture plane and the rolling direction which suggests that the PM alloys are strongly textured.

Anisotropic and heterogeneous mechanical properties of a stratified shale/limestone sequence at Nash Point, South Wales: A case study for hydraulic fracture propagation through a layered medium

NASA Astrophysics Data System (ADS)

Forbes Inskip, Nathaniel; Meredith, Philip; Gudmundsson, Agust

2016-04-01

While considerable effort has been expended on the study of fracture propagation in rocks in recent years, our understanding of how fractures propagate through layered sedimentary rocks with different mechanical and elastic properties remains poorly constrained. Yet this is a key issue controlling the propagation of both natural and anthropogenic hydraulic fractures in layered sequences. Here we report measurements of the contrasting mechanical and elastic properties of the Lower Lias at Nash Point, South Wales, which comprises an interbedded sequence of shale and limestone layers, and how those properties may influence fracture propagation. Elastic properties of both materials have been characterised via ultrasonic wave velocity measurements as a function of azimuth on samples cored both normal and parallel to bedding. The shale is highly anisotropic, with P-wave velocities varying from 2231 to 3890 m s-1, giving an anisotropy of ~55%. By contrast, the limestone is essentially isotropic, with a mean P-wave velocity of 5828 m s-1 and an anisotropy of ~2%. The dynamic Young's modulus of the shale, calculated from P- and S-wave velocity data, is also anisotropic with a value of 36 GPa parallel to bedding and 12 GPa normal to bedding. The modulus of the limestone is again isotropic with a value of 80 GPa. It follows that for a vertical fracture propagating (i.e. normal to bedding) the modulus contrast is 6.6. This is important because the contrast in elastic properties is a key factor in controlling whether fractures arrest, deflect, or propagate across interfaces between layers in a sequence. There are three principal mechanisms by which a fracture may deflect across or along an interface, namely: Cook-Gordon debonding, stress barrier, and elastic mismatch. Preliminary numerical modelling results (using a Finite Element Modelling software) of induced fractures at Nash Point suggest that all three are important. The results demonstrate a rotation of the maximum principal compressive stress across an interface but also a confinement of tensile stress within the host layer. Mechanical properties have been characterised by indirect measurement of the tensile strength using the Brazil-Disk technique. Measurements were made in the three principal orientations relative to bedding, Arrester, Divider, and Short-Transverse, and also at 15° intervals between these planes. Values for the shale again showed a high degree of anisotropy; with similar values in the Arrester and Divider orientations, but with much lower values in the Short-Transverse (bedding parallel) orientation. The tensile strength of the limestone is considerably higher than that of the shale and exhibits no significant anisotropy. Current work is underway to characterise the fracture propagation properties by measuring the fracture toughness and fracture ductility of both rocks using a combination of the Semi-Circular Bend and Short-Rod techniques.

Immediate versus delayed intramedullary nailing for open fractures of the tibial shaft: a multivariate analysis of factors affecting deep infection and fracture healing.

PubMed

Yokoyama, Kazuhiko; Itoman, Moritoshi; Uchino, Masataka; Fukushima, Kensuke; Nitta, Hiroshi; Kojima, Yoshiaki

2008-10-01

The purpose of this study was to evaluate contributing factors affecting deep infection and fracture healing of open tibia fractures treated with locked intramedullary nailing (IMN) by multivariate analysis. We examined 99 open tibial fractures (98 patients) treated with immediate or delayed locked IMN in static fashion from 1991 to 2002. Multivariate analyses following univariate analyses were derived to determine predictors of deep infection, nonunion, and healing time to union. The following predictive variables of deep infection were selected for analysis: age, sex, Gustilo type, fracture grade by AO type, fracture location, timing or method of IMN, reamed or unreamed nailing, debridement time (< or =6 h or >6 h), method of soft-tissue management, skin closure time (< or =1 week or >1 week), existence of polytrauma (ISS< 18 or ISS> or =18), existence of floating knee injury, and existence of superficial/pin site infection. The predictive variables of nonunion selected for analysis was the same as those for deep infection, with the addition of deep infection for exchange of pin site infection. The predictive variables of union time selected for analysis was the same as those for nonunion, excluding of location, debridement time, and existence of floating knee and superficial infection. Six (6.1%; type II Gustilo n=1, type IIIB Gustilo n=5) of the 99 open tibial fractures developed deep infections. Multivariate analysis revealed that timing or method of IMN, debridement time, method of soft-tissue management, and existence of superficial or pin site infection significantly correlated with the occurrence of deep infection (P< 0.0001). In the immediate nailing group alone, the deep infection rate in type IIIB + IIIC was significantly higher than those in type I + II and IIIA (P = 0.016). Nonunion occurred in 17 fractures (20.3%, 17/84). Multivariate analysis revealed that Gustilo type, skin closure time, and existence of deep infection significantly correlated with occurrence of nonunion (P < 0.05). Gustilo type and existence of deep infection were significantly correlated with healing time to union on multivariate analysis (r(2) = 0.263, P = 0.0001). Multivariate analyses for open tibial fractures treated with IMN showed that IMN after EF (especially in existence of pin site infection) was at high risk of deep infection, and that debridement within 6 h and appropriate soft-tissue managements were also important factor in preventing deep infections. These analyses postulated that both the Gustilo type and the existence of deep infection is related with fracture healing in open fractures treated with IMN. In addition, immediate IMN for type IIIB and IIIC is potentially risky, and canal reaming did not increase the risk of complication for open tibial fractures treated with IMN.

Tensile Property of ANSI 304 Stainless Steel Weldments Subjected to Cavitation Erosion Based on Treatment of Laser Shock Processing.

PubMed

Zhang, Lei; Liu, Yue-Hua; Luo, Kai-Yu; Zhang, Yong-Kang; Zhao, Yong; Huang, Jian-Yun; Wu, Xu-Dong; Zhou, Chuang

2018-05-16

Tensile property was one important index of mechanical properties of ANSI 304 stainless steel laser weldments subjected to cavitation erosion (CE). Laser shock processing (LSP) was utilized to strengthen the CE resistance, and the tensile property and fracture morphology were analyzed through three replicated experiment times. Results showed tensile process of treated weldments was composed of elastic deformation, plastic deformation, and fracture. The elastic limit, elastic modulus, elongation, area reduction, and ultimate tensile strength of tensile sample after CE were higher in view of LSP. In the fracture surface, the fiber zone, radiation zone and shear lip zone were generated, and those were more obvious through LSP. The number and size of pores in the fracture surface were smaller, and the fracture surface was smoother and more uniform. The dimples were elongated along the unified direction due to effects of LSP, and the elongated direction was in agreement with the crack propagation direction. Their distribution and shape were uniform with deeper depth. It could be reflected that the tensile property was improved by LSP and the CE resistance was also enhanced.

Tensile Property of ANSI 304 Stainless Steel Weldments Subjected to Cavitation Erosion Based on Treatment of Laser Shock Processing

PubMed Central

Zhang, Lei; Liu, Yue-Hua; Luo, Kai-Yu; Zhang, Yong-Kang; Zhao, Yong; Huang, Jian-Yun; Wu, Xu-Dong; Zhou, Chuang

2018-01-01

Tensile property was one important index of mechanical properties of ANSI 304 stainless steel laser weldments subjected to cavitation erosion (CE). Laser shock processing (LSP) was utilized to strengthen the CE resistance, and the tensile property and fracture morphology were analyzed through three replicated experiment times. Results showed tensile process of treated weldments was composed of elastic deformation, plastic deformation, and fracture. The elastic limit, elastic modulus, elongation, area reduction, and ultimate tensile strength of tensile sample after CE were higher in view of LSP. In the fracture surface, the fiber zone, radiation zone and shear lip zone were generated, and those were more obvious through LSP. The number and size of pores in the fracture surface were smaller, and the fracture surface was smoother and more uniform. The dimples were elongated along the unified direction due to effects of LSP, and the elongated direction was in agreement with the crack propagation direction. Their distribution and shape were uniform with deeper depth. It could be reflected that the tensile property was improved by LSP and the CE resistance was also enhanced. PMID:29772661

Strain Measurements within Fibre Boards. Part II: Strain Concentrations at the Crack Tip of MDF Specimens Tested by the Wedge Splitting Method

PubMed Central

Sinn, Gerhard; Müller, Ulrich; Konnerth, Johannes; Rathke, Jörn

2012-01-01

This is the second part of an article series where the mechanical and fracture mechanical properties of medium density fiberboard (MDF) were studied. While the first part of the series focused on internal bond strength and density profiles, this article discusses the fracture mechanical properties of the core layer. Fracture properties were studied with a wedge splitting setup. The critical stress intensity factors as well as the specific fracture energies were determined. Critical stress intensity factors were calculated from maximum splitting force and two-dimensional isotropic finite elements simulations of the specimen geometry. Size and shape of micro crack zone were measured with electronic laser speckle interferometry. The process zone length was approx. 5 mm. The specific fracture energy was determined to be 45.2 ± 14.4 J/m2 and the critical stress intensity factor was 0.11 ± 0.02 MPa.

2016 Accomplishments. Tritium aging studies on stainless steel. Forging process effects on the fracture toughness properties of tritium-precharged stainless steel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morgan, Michael J.

Forged austenitic stainless steels are used as the materials of construction for pressure vessels designed to contain tritium at high pressure. These steels are highly resistant to tritium-assisted fracture but their resistance can depend on the details of the forging microstructure. During FY16, the effects of forging strain rate and deformation temperature on the fracture toughness properties of tritium-exposed-and-aged Type 304L stainless steel were studied. Forgings were produced from a single heat of steel using four types of production forging equipment – hydraulic press, mechanical press, screw press, and high-energy-rate forging (HERF). Each machine imparted a different nominal strain ratemore » during the deformation. The objective of the study was to characterize the J-Integral fracture toughness properties as a function of the industrial strain rate and temperature. The second objective was to measure the effects of tritium and decay helium on toughness. Tritium and decay helium effects were measured by thermally precharging the as-forged specimens with tritium gas at 34.5 MPa and 350°C and aging for up to five years at -80°C to build-in decay helium prior to testing. The results of this study show that the fracture toughness properties of the as-forged steels vary with forging strain rate and forging temperature. The effect is largely due to yield strength as the higher-strength forgings had the lower toughness values. For non-charged specimens, fracture toughness properties were improved by forging at 871°C versus 816°C and Screw-Press forgings tended to have lower fracture toughness values than the other forgings. Tritium exposures reduced the fracture toughness values remarkably to fracture toughness values averaging 10-20% of as-forged values. However, forging strain rate and temperature had little or no effect on the fracture toughness after tritium precharging and aging. The result was confirmed by fractography which indicated that fracture modes in the tritium-exposed specimens were similar for all forgings. Another FY16 objective was to prepare fracture toughness specimens from Types 304L and 21-6-9 stainless steel weldments and heat-affected zones (HAZ) for tritium charging.« less

Rock fracture processes in chemically reactive environments

NASA Astrophysics Data System (ADS)

Eichhubl, P.

2015-12-01

Rock fracture is traditionally viewed as a brittle process involving damage nucleation and growth in a zone ahead of a larger fracture, resulting in fracture propagation once a threshold loading stress is exceeded. It is now increasingly recognized that coupled chemical-mechanical processes influence fracture growth in wide range of subsurface conditions that include igneous, metamorphic, and geothermal systems, and diagenetically reactive sedimentary systems with possible applications to hydrocarbon extraction and CO2 sequestration. Fracture processes aided or driven by chemical change can affect the onset of fracture, fracture shape and branching characteristics, and fracture network geometry, thus influencing mechanical strength and flow properties of rock systems. We are investigating two fundamental modes of chemical-mechanical interactions associated with fracture growth: 1. Fracture propagation may be aided by chemical dissolution or hydration reactions at the fracture tip allowing fracture propagation under subcritical stress loading conditions. We are evaluating effects of environmental conditions on critical (fracture toughness KIc) and subcritical (subcritical index) fracture properties using double torsion fracture mechanics tests on shale and sandstone. Depending on rock composition, the presence of reactive aqueous fluids can increase or decrease KIc and/or subcritical index. 2. Fracture may be concurrent with distributed dissolution-precipitation reactions in the hostrock beyond the immediate vicinity of the fracture tip. Reconstructing the fracture opening history recorded in crack-seal fracture cement of deeply buried sandstone we find that fracture length growth and fracture opening can be decoupled, with a phase of initial length growth followed by a phase of dominant fracture opening. This suggests that mechanical crack-tip failure processes, possibly aided by chemical crack-tip weakening, and distributed solution-precipitation creep in the hostrock can independently affect fracture opening displacement and thus fracture aperture profiles and aperture distribution.

Hydraulic fracturing in shales: the spark that created an oil and gas boom

NASA Astrophysics Data System (ADS)

Olson, J. E.

2017-12-01

In the oil and gas business, one of the valued properties of a shale was its lack of flow capacity (its sealing integrity) and its propensity to provide mechanical barriers to hydraulic fracture height growth when exploiting oil and gas bearing sandstones. The other important property was the high organic content that made shale a potential source rock for oil and gas, commodities which migrated elsewhere to be produced. Technological advancements in horizontal drilling and hydraulic fracturing have turned this perspective on its head, making shale (or other ultra-low permeability rocks that are described with this catch-all term) the most prized reservoir rock in US onshore operations. Field and laboratory results have changed our view of how hydraulic fracturing works, suggesting heterogeneities like bedding planes and natural fractures can cause significant complexity in hydraulic fracture growth, resulting in induced networks of fractures whose details are controlled by factors including in situ stress contrasts, ductility contrasts in the stratigraphy, the orientation and strength of pre-existing natural fractures, injection fluid viscosity, perforation cluster spacing and effective mechanical layer thickness. The stress shadowing and stress relief concepts that structural geologists have long used to explain joint spacing and orthogonal fracture pattern development in stratified sequences are key to understanding optimal injection point spacing and promotion of more uniform length development in induced hydraulic fractures. Also, fracture interaction criterion to interpret abutting vs crossing natural fracture relationships in natural fracture systems are key to modeling hydraulic fracture propagation within natural fractured reservoirs such as shale. Scaled physical experiments provide constraints on models where the physics is uncertain. Numerous interesting technical questions remain to be answered, and the field is particularly appealing in that better geologic understanding of the stratigraphic heterogeneity and material property attributes of shale can have a direct effect on the engineering design of wellbores and stimulation treatments.

Effect of a high helium content on the flow and fracture properties of a 9Cr martensitic steel

NASA Astrophysics Data System (ADS)

Henry, J.; Vincent, L.; Averty, X.; Marini, B.; Jung, P.

2007-08-01

An experimental characterization was conducted of helium effects on the mechanical properties of a 9Cr martensitic steel. Six sub-size Charpy samples were implanted in the notch region at 250 °C with 0.25 at.% helium and subsequently tested in 3-point bending at room temperature. Brittle fracture mode (cleavage and intergranular fracture) was systematically observed in the implanted zones of the samples. Finite element calculations of the tests, using as input the tensile properties measured on a helium loaded sample, were performed in order to determine the fracture stress at the onset of brittle crack propagation. Preliminary TEM investigations of the implantation-induced microstructure revealed a high density of small helium bubbles.

Use of fibular bone graft and cancellous screw fixation in the management of neglected femur neck fractures in young patients.

PubMed

Khani, Ghulam Mustafa Kaim; Hafeez, Kamran; Bux, Muhammad; Rasheed, Nusrat; Ahmed, Naveed; Anjum, M Perwez

2017-01-01

To present the clinical outcome of patients with neglected femur neck fracture treated with fibular bone graft. During May 2010-February 2013, 15 patients younger than 35 years of age with neglected fracture neck of femur were managed with non-vascularized fibular graft and cannulated screws. Fractures were classified according to Sandhu Classification. Hip function was assessed using Harris hip score. Fifteen patients with mean age of 28.67 years were managed. Mean period of delay from injury to presentation was 3.07 months. Mean follow-up was 18.5 months. Union was achieved in 13 cases. 2 patients developed nonunion with progression of avascular necrosis (AVN). Patients with healed fracture did not show radiological signs of AVN till the past follow-up. Functional status was evaluated at 6 months according to Harris hip score and was poor in 2 patients, fair in 2 patients, good in 6 patients, and excellent in 5 patients. Fibular graft along with two cancellous screws proved to be an effective technique in our cases with neglected femur neck fractures.

Obturator Artery Injury Resulting in Massive Hemorrhage From a Low-Energy Pubic Ramus Fracture.

PubMed

Solarz, Mark K; Kistler, Justin M; Rehman, Saqib

2017-05-01

Pelvic ring fractures are common in the elderly population and are usually a result of low-energy trauma, such as falls from standing. In most cases, low-energy pelvic ring injuries can be treated with appropriate analgesia and early mobilization. Arterial injury resulting in hemodynamic instability from a low-energy pelvic ring injury is rare but, given the poor compliance of vessels in the elderly population, possible. These patients must be carefully monitored after the initial injury. The purpose of this report is to describe an elderly patient who sustained a superior pubic ramus fracture and arterial injury following a low-energy fall from standing that required angiographic intervention. Elderly patients who sustain low-energy or pelvic insufficiency fractures are unlike the younger population with high-energy pelvic fractures and hemodynamic collapse. Elderly patients can have a delayed presentation of arterial injury and require careful physical examination and close monitoring. Additionally, the authors provide a review of the literature for low-energy pelvic fractures. [Orthopedics. 2017; 40(3):e546-e548.]. Copyright 2017, SLACK Incorporated.

Treatment of close-range, low-velocity gunshot fractures of tibia and femur diaphysis with consecutive compression-distraction technique: a report of 11 cases.

PubMed

Ateşalp, A Sabri; Kömürcü, Mahmut; Demiralp, Bahtiyar; Bek, Dogan; Oğuz, Erbil; Yanmiş, Ibrahim

2004-01-01

Lower extremity injuries secondary to close-range, low-velocity gunshot wounds are frequently seen in both civilian and military populations. A close-range, low-velocity injury produces high energy and often results in comminuted and complicated fractures with significant morbidity. In this study, four femoral, four tibial, and three combined tibia and fibular comminuted diaphyseal fractures secondary to close-range, low-velocity gunshot wounds in 11 military personnel were treated with debridement followed by compression-distraction lengthening using a circular external fixator frame. Fracture union was obtained in all without significant major complications. Fracture consolidation occurred at a mean of 3.5 months. At follow-up of 46.8 months, there were no delayed unions, nonunions, or malunions. Minor complications included four pin-tract infections and knee flexion limitation in two femur fractures. Osteomyelitis and deep soft tissue infection were not observed. This technique provided an alternative to casting, open reduction internal fixation, or intermedullary fixation with an acceptable complication rate.

Shear Wave Splitting analysis of borehole microseismic reveals weak azimuthal anisotropy hidden behind strong VTI fabric of Lower Paleozoic shales in northern Poland

NASA Astrophysics Data System (ADS)

Gajek, Wojciech; Verdon, James; Malinowski, Michał; Trojanowski, Jacek

2017-04-01

Azimuthal anisotropy plays a key-role in hydraulic fracturing experiments, since it provides information on stress orientation and pre-existing fracture system presence. The Lower Paleozoic shale plays in northern Poland are characterized by a strong (15-18%) Vertical Transverse Isotropy (VTI) fabric which dominates weak azimuthal anisotropy being of order of 1-2%. A shear wave travelling in the subsurface after entering an anisotropic medium splits into two orthogonally polarized waves travelling with different velocities. Splitting parameters which can be assessed using a microseismic array are polarization of the fast shear wave and time delay between two modes. Polarization of the fast wave characterizes the anisotropic system on the wave path while the time delay is proportional to the magnitude of anisotropy. We employ Shear Wave Splitting (SWS) technique using a borehole microseismic dataset collected during a hydraulic stimulation treatment located in northern Poland, to image fracture strike masked by a strong VTI signature. During the inversion part, the VTI background parameters were kept constant using information from 3D seismic (VTI model used for pre-stack depth migration). Obtained fracture azimuths averaged over fracturing stages are consistent with the available XRMI imager logs from the nearby vertical well, however they are different from the large-scale maximum stress direction (by 40-45 degrees). Inverted Hudson's crack density (ca. 2%) are compatible with the low shear-wave anisotropy observed in the cross-dipole sonic logs (1-2%). This work has been funded by the Polish National Centre for Research and Development within the Blue Gas project (No BG2/SHALEMECH/14). Data were provided by the PGNiG SA. Collaboration with University of Bristol was supported within TIDES COST Action ES1401.

Outcome Analysis following Operative Skeletal Stabilization in Established Non Unions of Malleolar Fractures - A Series of 11 Cases.

PubMed

Balasubramanian, Navin; Babu, Ganesh; Prakasam, Sindhuja

2015-01-01

Established non-unions pose a real nightmare for even the most accomplished surgeon. The variations in anatomy due to extensive fibrous tissue growth, soft tissue contractures around the fracture site and bony alterations like smoothening and sclerosis of the fracture ends must each be addressed as a whole if good outcome is to be expected. Here we present a series of 11 patients who had bimalleolar fracture of the ankle following which they had native splinting. These patients presented to us with established non-union. There were 7 males and 4 females in the study. The average age was 44.63 years. Ten out of the 11 patients went on to union (90.1%) following internal fixation with or without immobilization in a plaster cast at an average of 13.8 weeks (range 12-17 weeks). The remaining patient did not progress to union and was advised revision fixation but she refused. She was put on an ankle foot orthoses and mobilized with satisfactory results. There was no infection in any of the patients. Two patients had delayed wound healing with delayed suture removal at 18 days. Weight bearing was started at the end of 16 weeks in all the patients. All patients were assessed using the Karlsson and Peterson functional score for the ankle. Six patients had excellent outcome, 3 had good outcome, 2 had fair with one patient having poor functional result. We conclude that open reduction internal fixation +/- bone grafting provides excellent union rates and good functional results in even the most established non unions of bimalleolar fractures of the ankle.

History of internal fixation with plates (part 2): new developments after World War II; compressing plates and locked plates.

PubMed

Hernigou, Philippe; Pariat, Jacques

2017-07-01

The first techniques of operative fracture with plates were developed in the 19th century. In fact, at the beginning these methods consisted of an open reduction of the fracture usually followed by a very unstable fixation. As a consequence, the fracture had to be opened with a real risk of (sometimes lethal) infection, and due to unstable fixation, protection with a cast was often necessary. During the period between World Wars I and II, plates for fracture fixation developed with great variety. It became increasingly recognised that, because a fracture of a long bone normally heals with minimal resorption at the bone ends, this may result in slight shortening and collapse, so a very rigid plate might prevent such collapse. However, as a consequence, delayed healing was observed unless the patient was lucky enough to have the plate break. One way of dealing with this was to use a slotted plate in which the screws could move axially, but the really important advance was recognition of the role of compression. After the first description of compression by Danis with a "coapteur", Bagby and Müller with the AO improved the technique of compression. The classic dynamic compression plates from the 1970s were the key to a very rigid fixation, leading to primary bone healing. Nevertheless, the use of strong plates resulted in delayed union and the osteoporosis, cancellous bone, comminution, and/or pathological bone resulted in some failures due to insufficient stability. Finally, new devices represented by locking plates increased the stability, contributing to the principles of a more biological osteosynthesis while giving enough stability to allow immediate full weight bearing in some patients.

Tensile and fracture properties of type 316 stainless steel after creep

NASA Astrophysics Data System (ADS)

Gan, D.

1982-12-01

The effects of creep on the mechanical properties of type 316 stainless steel were studied. Tensile and Charpy specimens were machined from the oversize specimens crept at 750 °C and 103 MPa. The ambient fracture energy was found to deteriorate rapidly after creep. The ambient yield stress was increased moderately, but the tensile ductility was severely reduced. The effects of intergranular carbides alone on mechanical properties were studied with specimens thermal aged without load. These carbides were shown to cause a moderate reduction in fracture energy and tensile ductility but had little effect on yield stress. Extensive grain boundary separations were observed on the fracture surfaces. SEM studies showed that these grain boundaries were covered with micro voids initiated by the dense intergranular carbides. Frequently, large dimples on grain boundary joined up and initiated shear fracture into the grain. In the crept specimens additional microstructural changes in the form of intragranular carbides and subgrain boundaries were observed. Both are responsible for the increase in yield stress and the further reduction in tensile ductility and fracture energy. The intragranular carbides also modified the size and density of the dimples on the fracture surfaces.

Spartan Release Engagement Mechanism (REM) stress and fracture analysis

NASA Technical Reports Server (NTRS)

Marlowe, D. S.; West, E. J.

1984-01-01

The revised stress and fracture analysis of the Spartan REM hardware for current load conditions and mass properties is presented. The stress analysis was performed using a NASTRAN math model of the Spartan REM adapter, base, and payload. Appendix A contains the material properties, loads, and stress analysis of the hardware. The computer output and model description are in Appendix B. Factors of safety used in the stress analysis were 1.4 on tested items and 2.0 on all other items. Fracture analysis of the items considered fracture critical was accomplished using the MSFC Crack Growth Analysis code. Loads and stresses were obtaind from the stress analysis. The fracture analysis notes are located in Appendix A and the computer output in Appendix B. All items analyzed met design and fracture criteria.

Stress fluctuations in fracture networks from theoretical and numerical models

NASA Astrophysics Data System (ADS)

Davy, P.; Darcel, C.; Mas Ivars, D.; Le Goc, R.

2017-12-01

We analyze the spatial fluctuations of stress in a simple tridimensional model constituted by a population of disc-shaped fractures embedded in an elastic matrix with uniform and isotropic properties. The fluctuations arise from the classical stress enhancement at fracture tips and stress shadowing around fracture centers that are amplified or decreased by the interactions between close-by fractures. The distribution of local stresses is calculated at the elementary mesh scale with the 3DEC numerical program based on the distinct element method. As expected, the stress distributions vary with fracture density, the larger is the density, the wider is the distribution. For freely slipping fractures, it is mainly controlled by the percolation parameter p (i.e., the total volume of spheres surrounding fractures). For stresses smaller than the remote deviatoric stress, the distribution depends only on for the range of density that has been studied. For large stresses, the distribution decreases exponentially when increasing stress, with a characteristic stress that increases with entailing a widening of the stress distribution. We extend the analysis to fractures with plane resistance defined by an elastic shear stiffness ks and a slip Coulomb threshold. A consequence of the fracture plane resistance is to lower the stress perturbation in the surrounding matrix by a factor that depends on the ratio between ks and a fracture-matrix stiffness km mainly dependent on the ratio between Young modulus and fracture size. km is also the ratio between the remote shear stress and the displacement across the fracture plane in the case of freely slipping fractures. A complete analytical derivation of the expressions of the stress perturbations and of the fracture displacements is obtained and checked with numerical simulations. In the limit ks >> km, the stress perturbation tends to 0 and the stress state is spatially uniform. The analysis allows us to quantify the intensity of the stress fluctuations in fractured rocks as a function of both the fracture network characteristics (density and size distribution), and the mechanical properties (fracture shear stiffness vs matrix elastic properties).

The litigation cost of negligent scaphoid fracture management.

PubMed

Harrison, William; Newton, Ashley W; Cheung, Graham

2015-04-01

The aims of the study were to quantify the litigation cost of scaphoid mismanagement, identify the main reasons why patients sought compensation and hence provide suggestions for reducing litigation. Data were obtained from the National Health Service Litigation Authority. All orthopaedic-related litigation between 1995 and 2010 in the UK was reviewed. Litigation specifically against mismanagement of scaphoid fractures were identified and grouped according to the plaintiff's complaint. Exclusions were all unsettled claims. There were 85 closed cases of scaphoid fracture mismanagement over 15 years. Reasons for litigation were as follows: seven failures in interpreting radiographs, 57 missed fractures, four fractures not immobilized, nine discharged too early, five delayed operations and three inappropriate surgeries. The mean cost was &OV0556;41 680 per case (range &OV0556;0-&OV0556;206 789), and a cumulative cost of &OV0556;3 542 855. The majority of litigation may relate to a lack of follow-up and may demonstrate a failure of protocol-driven reassessment. Secondary surveys following major trauma are also highly relevant.

Mobility one week after a hip fracture - can it be predicted?

PubMed

Fitzgerald, Michelle; Blake, Catherine; Askin, David; Quinlan, John; Coughlan, Tara; Cunningham, Caitriona

2018-05-01

Better patient outcomes and more efficient healthcare could be achieved by predicting post hip fracture function at an early stage. This study aimed to identify independent predictors of mobility outcome one week post hip fracture surgery. All hip fracture inpatients (n=77) were included in this 6 month prospective observational cohort study. Predictor variables were obtained on the first postoperative day and included premorbid function using the New Mobility Score (NMS). Mobility outcome measures one week postoperatively included the Cumulated Ambulatory Score (CAS). Data were analysed with SPSS using binary multiple logistic regression analysis RESULTS: Patients who fell outdoors (OR 3.848; 95% CI, 1.053-14.061), had no delay to surgery (OR 5.472; 95% CI, 1.073-27.907) and had high pre-fracture function (OR3.366; 95% CI, 1.042-10.879) were predicted to achieve independent mobility (CAS = 6) one week postoperatively. Fall location, time to surgery and baseline function predict independent mobility one week after hip fracture, and can be used for early rehabilitation stratification. The NMS and CAS are recommended as standardised hip fracture clinical measures. Orthogeriatric and physiotherapy service initiatives may improve early functional outcome. Copyright © 2017. Published by Elsevier Ltd.

Interactions between MSCs and Immune Cells: Implications for Bone Healing

PubMed Central

Kovach, Tracy K.; Dighe, Abhijit S.; Lobo, Peter I.; Cui, Quanjun

2015-01-01

It is estimated that, of the 7.9 million fractures sustained in the United States each year, 5% to 20% result in delayed or impaired healing requiring therapeutic intervention. Following fracture injury, there is an initial inflammatory response that plays a crucial role in bone healing; however, prolonged inflammation is inhibitory for fracture repair. The precise spatial and temporal impact of immune cells and their cytokines on fracture healing remains obscure. Some cytokines are reported to be proosteogenic while others inhibit bone healing. Cell-based therapy utilizing mesenchymal stromal cells (MSCs) is an attractive option for augmenting the fracture repair process. Osteoprogenitor MSCs not only differentiate into bone, but they also exert modulatory effects on immune cells via a variety of mechanisms. In this paper, we review the current literature on both in vitro and in vivo studies on the role of the immune system in fracture repair, the use of MSCs in the enhancement of fracture healing, and interactions between MSCs and immune cells. Insight into this paradigm can provide valuable clues in identifying cellular and noncellular targets that can potentially be modulated to enhance both natural bone healing and bone repair augmented by the exogenous addition of MSCs. PMID:26000315

Biological Perspectives of Delayed Fracture Healing

PubMed Central

Hankenson, KD; Zmmerman, G; Marcucio, R

2015-01-01

Fracture healing is a complex biological process that requires interaction among a series of different cell types. Maintaining the appropriate temporal progression and spatial pattern is essential to achieve robust healing. We can temporally assess the biological phases via gene expression, protein analysis, histologically, or non-invasively using biomarkers as well as imaging techniques. However, determining what leads to normal verses abnormal healing is more challenging. Since the ultimate outcome of the process of fracture healing is to restore the original functions of bone, assessment of fracture healing should include not only monitoring the restoration of structure and mechanical function, but also an evaluation of the restoration of normal bone biology. Currently very few non-invasive measures of the biology of healing exist; however, recent studies that have correlated non-invasive measures with fracture healing outcome in humans have shown that serum TGFbeta1 levels appear to be an indicator of healing vs non-healing. In the future, developing additional serum measures to assess biological healing will improve the reliability and permit us to assess stages of fracture healing. Additionally, new functional imaging technologies could prove useful for better understanding both normal fracture healing and predicting dysfunctional healing in human patients. PMID:24857030

The Effects of Obesity on Murine Cortical Bone

NASA Astrophysics Data System (ADS)

Martin, Sophi

This dissertation details the effects of obesity on the mechanical properties and structure of cortical bone. Obesity is associated with greater bone mineral content that might be expected to protect against fracture, which has been observed in adults. Paradoxically however, the incidence of bone fractures has been found to increase in overweight and obese children and adolescents. Femora from adolescent and adult mice fed a high-fat diet are investigated for changes in shape, tissue structure, as well as tissue-level and whole-bone mechanical properties. Results indicate increased bone size, reduced size-independent mechanical properties, but maintained size-dependent mechanical properties. Other changes in cortical bone response to obesity are observed with advancing age. This study indicates that bone quantity and bone quality play important compensatory roles in determining fracture risk, and that fracture risk may not be lessened for adults as previously thought.

Does timing of presentation of penile fracture affect outcome of surgical intervention?

PubMed

el-Assmy, Ahmed; el-Tholoth, Hossam S; Mohsen, Tarek; Ibrahiem, el-Housseiny I

2011-06-01

To assess the effect of timing of presentation of cases with penile fracture on the outcome of surgical intervention. Between January 1986 and May 2010, 180 patients with penile fracture were treated surgically in our center. To assess the effect of timing of presentation, patients were classified into 2 groups: group I with early presentation (≤24 hours) and group II with delayed presentation (>24 hours). All patients were contacted by mail or phone and were re-evaluated. All patients were reevaluated by questionnaire and local examination. Patients with erectile dysfunction were evaluated by color Doppler ultrasonography. Group I included 149 patients (82.8%) and group II included 31 (17.2%). In group I, patients presented to the emergency department from 1-24 hours (mean, 11.8) after occurrence of the penile trauma. Although patients in group II presented from 30 hours to 7 days (mean, 44.7 hours). Both groups were similar regarding etiology of injury, clinical presentation, surgical findings, and incidence of associated urethral injury. Mean follow-up period for group I was 105 months, and for group II it was 113 months. After such long-term follow up, 35 (19.4%) patients had complications; however, there was no statistically significant difference between both groups. Cases of penile fracture with early or delayed presentation up to 7 days should be managed surgically. Both groups have comparable excellent outcome with no serious long-term complications. Copyright © 2011 Elsevier Inc. All rights reserved.

Surgical treatment of distal tibia fractures: open versus MIPO.

PubMed

Gülabi, Deniz; Bekler, Halil İbrahim; Sağlam, Fevzi; Taşdemir, Zeki; Çeçen, Gültekin Sıtkı; Elmalı, Nurzat

2016-01-01

Treatment of the distal tibial fractures are challenging due to the limited soft tissue, subcutaneous location and poor vascularity. In this control-matched study, it was aimed to compare the traditional open reduction and internal fixation with minimal invasive plating (MIPO). We hypothesized that superior results may be achieved with MIPO technique. 22 patients treated with traditional open reduction and internal fixation were matched with 22 patients treated with closed reduction and MIPO on the basis of age (±3), gender, and fracture pattern (AO classification). Evaluation was assed according to the wound problems, the American Orthopaedic Foot and Ankle surgery (AOFAS) scoring, radiological union, malunion, delayed union, hospitalisation time, time from injury to surgery, and operation time. There was no significant difference in the distribution of AO/OTA classification, age, gender, AOFAS score, time from injury to operation, follow-up, bone union time, delayed union, malunion and infection (p>0.05). The operation time was significantly longer in the open group than in the MIPO group: 69.59±7.21 min. for the ORIF, and 61.14±5.61 for the MIPO group (p<0.01).The hospitalisation time was significantly longer in the open group than in the MIPO group: 7.64±4.71 days for the MIPO, and 10.18±4.32 days for the ORIF group (p<0.05). MIPO technique can be beneficial for the treatment of distal tibia AO/OTA A and B type fractures with reduced hospital stay, cost-effectiveness, and infection rate.

Effect of early realignment on length and delayed repair of postpelvic fracture urethral injury.

PubMed

Koraitim, Mamdouh M

2012-04-01

To determine the effect of early realignment of posterior urethral injury on the length and delayed repair of ensuing urethral defect. We reviewed the medical records of 120 patients with a pelvic fracture urethral defect who were referred for delayed repair from elsewhere from 1995 to 2009. The review was focused on 5 variables: initial management of urethral injury, length of urethral defect, type of delayed repair, continence, and erectile function. Of the patients, 26 were excluded from the study and 94 were categorized as having been initially treated by realignment (42 patients, group 1) or suprapubic cystostomy (52 patients, group 2). Urethral defects ≤ 2 cm in length were found in 28 patients (67%) in group 1 versus 22 (42%) in group 2. Defects >2 cm were found in 14 patients (33%) in group 1 versus 30 (58%) in group 2. The repair was accomplished by a simple perineal operation in 32 (76%) and 30 (58%) patients in groups 1 and 2, respectively. An elaborated perineal or perineo-abdominal procedure was required in 10 (24%) and 22 (42%) patients in groups 1 and 2, respectively (all P < .05). Incontinence occurred in 1 patient in group 1. Impotence developed in 10 (28%) of 36 realigned adults and in 2 (5%) of 38 adults with suprapubic cystostomy. Early realignment of posterior urethral injury decreases the length of the ensuing urethral defect and facilitates its delayed repair. Incontinence and impotence appear to result from the injury itself and not the treatment. Copyright © 2012 Elsevier Inc. All rights reserved.

Functional outcomes of "floating elbow" injuries in adult patients.

PubMed

Yokoyama, K; Itoman, M; Kobayashi, A; Shindo, M; Futami, T

1998-05-01

To assess elbow function, complications, and problems of floating elbow fractures in adults receiving surgical treatment. Retrospective clinical review. Level I trauma center in Kanagawa, Japan. Fourteen patients with fifteen floating elbow injuries, excluding one immediate amputation, seen at the Kitasato University Hospital from January 1, 1984, to April 30, 1995. All fractures were managed surgically by various methods. In ten cases, the humeral and forearm fractures were treated simultaneously with immediate fixation. In three cases, both the humeral and forearm fractures were treated with delayed fixation on Day 1, 4, or 7. In the remaining two cases, the open forearm fracture was managed with immediate fixation and the humerus fracture with delayed fixation on Day 10 or 25. All subjects underwent standardized elbow evaluations, and results were compared with an elbow score based on a 100-point scale. The parameters evaluated were pain, motion, elbow and grip strength, and function during daily activities. Complications such as infections, nonunions, malunions, and refractures were investigated. Mean follow-up was forty-three months (range 13 to 112 months). At final follow-up, the mean elbow function score was 79 points, with 67 percent (ten of fifteen) of the subjects having good or excellent results. The functional outcome did not correlate with the Injury Severity Score of the individual patients, the existence of open injuries or neurovascular injuries, or the timing of surgery. There were one deep infection, two nonunions of the humerus, two nonunions of the forearm, one varus deformity of the humerus, and one forearm refracture. Based on the present data, we could not clarify the factors influencing the final functional outcome after floating elbow injury. These injuries, however, potentially have many complications, such as infection or nonunion, especially when there is associated brachial plexus injury. We consider that floating elbow injuries are severe injuries and that surgical stabilization is needed; beyond that, there are no specific forms of surgical treatment to reliably guarantee excellent results.

Management of anticoagulation in hip fractures: A pragmatic approach.

PubMed

Yassa, Rafik; Khalfaoui, Mahdi Yacine; Hujazi, Ihab; Sevenoaks, Hannah; Dunkow, Paul

2017-09-01

Hip fractures are common and increasing with an ageing population. In the United Kingdom, the national guidelines recommend operative intervention within 36 hours of diagnosis. However, long-term anticoagulant treatment is frequently encountered in these patients which can delay surgical intervention. Despite this, there are no set national standards for management of drug-induced coagulopathy pre-operatively in the context of hip fractures.The aim of this study was to evaluate the management protocols available in the current literature for the commonly encountered coagulopathy-inducing agents.We reviewed the current literature, identified the reversal agents used in coagulopathy management and assessed the evidence to determine the optimal timing, doses and routes of administration.Warfarin and other vitamin K antagonists (VKA) can be reversed effectively using vitamin K with a dose in the range of 2 mg to 10 mg intravenously to correct coagulopathy.The role of fresh frozen plasma is not clear from the current evidence while prothrombin complex remains a reliable and safe method for immediate reversal of VKA-induced coagulopathy in hip fracture surgery or failed vitamin K treatment reversal.The literature suggests that surgery should not be delayed in patients on classical antiplatelet medications (aspirin or clopidogrel), but spinal or regional anaesthetic methods should be avoided for the latter. However, evidence regarding the use of more novel antiplatelet medications (e.g. ticagrelor) and direct oral anticoagulants remains a largely unexplored area in the context of hip fracture surgery. We suggest treatment protocols based on best available evidence and guidance from allied specialties.Hip fracture surgery presents a common management dilemma where semi-urgent surgery is required. In this article, we advocate an evidence-based algorithm as a guide for managing these anticoagulated patients. Cite this article: EFORT Open Rev 2017;2:394-402. DOI: 10.1302/2058-5241.2.160083.

Crack Initiation and Propagation Properties of HY 130 Steel Weldments Following Temper Embrittlement.

DTIC Science & Technology

1982-09-01

mechanics ( EPFM ) may be applied to engineering problems to determine material properties related to crack initiation and propagation. Specifically, these...Introduction The application of linear elastic fracture mechanics (LEFM) to engineering fracture analyses has become increasingly widespread and the use...structures to which the particular material was to be applied. The advent of elastic-plastic fracture mechanics ( EPFM ) has proven valuable because a

Misdiagnosis of Talar Body or Neck Fractures as Ankle Sprains in Low Energy Traumas

PubMed Central

Young, Ki-Won; Kim, Jin-Su; Cho, Hun-Ki; Choo, Ho-Sik; Park, Jang-Ho

2016-01-01

Background The talus has a very complex anatomical morphology and is mainly fractured by a major force caused by a fall or a traffic accident. Therefore, a talus fracture is not common. However, many recent reports have shown that minor injuries, such as sprains and slips during sports activities, can induce a talar fracture especially in the lateral or posterior process. Still, fractures to the main parts of the talus (neck and body) after ankle sprains have not been reported as occult fractures. Methods Of the total 102 cases from January 2005 to December 2012, 7 patients had confirmed cases of missed/delayed diagnosis of a talus body or neck fracture and were included in the study population. If available, medical records, X-rays, computed tomography scans, and magnetic resonance imaging of the confirmed cases were retrospectively reviewed and analyzed. Results In the 7-patient population, there were 3 talar neck fractures and 4 talar body fractures (coronal shearing type). The mechanisms of injuries were all low energy trauma episodes. The causes of the injuries included twisting of the ankle during climbing (n = 2), jumping to the ground from a 1-m high wall (n = 2), and twisting of the ankle during daily activities (n = 3). Conclusions A talar body fracture and a talar neck fracture should be considered in the differential diagnosis of patients with acute and chronic ankle pain after a minor ankle injury. PMID:27583114

Parathyroid hormone and bone healing.

PubMed

Ellegaard, M; Jørgensen, N R; Schwarz, P

2010-07-01

Fracture healing is a complex process, and a significant number of fractures are complicated by impaired healing and non-union. Impaired healing is prevalent in certain risk groups, such as the elderly, osteoporotics, people with malnutrition, and women after menopause. Currently, no pharmacological treatments are available. There is therefore an unmet need for medications that can stimulate bone healing. Parathyroid hormone (PTH) is the first bone anabolic drug approved for the treatment of osteoporosis, and intriguingly a number of animal studies suggest that PTH could be beneficial in the treatment of fractures and could thus be a potentially new treatment option for induction of fracture healing in humans. Furthermore, fractures in animals with experimental conditions of impaired healing such as aging, estrogen withdrawal, and malnutrition can heal in an expedited manner after PTH treatment. Interestingly, fractures occurring at both cancellous and cortical sites can be treated successfully, indicating that both osteoporotic and nonosteoporotic fractures can be the target of PTH-induced healing. Finally, the data suggest that PTH partly prevents the delay in fracture healing caused by aging. Recently, the first randomized, controlled clinical trial investigating the effect of PTH on fracture healing was published, indicating a possible clinical benefit of PTH treatment in inducing fracture healing. The aim of this article is therefore to review the evidence for the potential of PTH in bone healing, including the underlying mechanisms for this, and to provide recommendations for the clinical testing and use of PTH in the treatment of impaired fracture healing in humans.

A double-plating approach to distal femur fracture: A clinical study.

PubMed

Steinberg, Ely L; Elis, Jacov; Steinberg, Yohai; Salai, Moshe; Ben-Tov, Tomer

2017-10-01

Locked plating is one of the latest innovative options for treating supracondylar femur fractures with relatively low failure rates. Single lateral plating was often found to have a relative higher failure rate. No clinical studies of double-plating distal femur fixation have thus far been reported. The aim of this study is to present our clinical experience with this surgical approach. Thirty-two patients (26 females and 6 males, mean age 76 years, range 44-101) were included in the study. Eight of them patients had a periprosthetic stable implant fracture and two patients were treated for a nonunion. All fractures, excluding one that needed bone grafting and one refracture, healed within 12 weeks. One patient needed bone grafting for delayed union and one patient needed fixation exchange due to femur re-fracture at the site of the most proximal screw. Two patients developed superficial wound infection and one patient required medial plate removal after union due to deep infection. Based on these promising results, we propose that the double-plating technique should be considered in the surgeon's armamentarium for the treatment of supracondylar femur fractures, particularly in patients with poor bone quality, comminuted fractures and very low periprosthetic fractures. Copyright © 2017 Elsevier Ltd. All rights reserved.

Audit, guidelines and standards: clinical governance for hip fracture care in Scotland.

PubMed

Currie, Colin T; Hutchison, James D

To report on experience of national-level audit, guidelines and standards for hip fracture care in Scotland. Scottish Hip Fracture Audit (from 1993) documents case-mix, process and outcomes of hip fracture care in Scotland. Evidence-based national guidelines on hip fracture care are available (1997, updated 2002). Hip fracture serves as a tracer condition by the health quality assurance authority for its work on older people, which reported in 2004. Audit data are used locally to document care and support and monitor service developments. Synergy between the guidelines and the audit provides a means of improving care locally and monitoring care nationally. External review by the quality assurance body shows to what extent guideline-based standards relating to A&E care, pre-operative delay, multidisciplinary care and audit participation are met. Three national-level initiatives on hip fracture care have delivered: Reliable and large-scale comparative information on case-mix, care and outcomes; evidence-based recommendations on care; and nationally accountable standards inspected and reported by the national health quality assurance authority. These developments are linked and synergistic, and enjoy both clinical and managerial support. They provide an evolving framework for clinical governance, with casemix-adjusted outcome assessment for hip fracture care as a next step.

Cartilage to bone transformation during fracture healing is coordinated by the invading vasculature and induction of the core pluripotency genes.

PubMed

Hu, Diane P; Ferro, Federico; Yang, Frank; Taylor, Aaron J; Chang, Wenhan; Miclau, Theodore; Marcucio, Ralph S; Bahney, Chelsea S

2017-01-15

Fractures heal predominantly through the process of endochondral ossification. The classic model of endochondral ossification holds that chondrocytes mature to hypertrophy, undergo apoptosis and new bone forms by invading osteoprogenitors. However, recent data demonstrate that chondrocytes transdifferentiate to osteoblasts in the growth plate and during regeneration, yet the mechanism(s) regulating this process remain unknown. Here, we show a spatially-dependent phenotypic overlap between hypertrophic chondrocytes and osteoblasts at the chondro-osseous border in the fracture callus, in a region we define as the transition zone (TZ). Hypertrophic chondrocytes in the TZ activate expression of the pluripotency factors [Sox2, Oct4 (Pou5f1), Nanog], and conditional knock-out of Sox2 during fracture healing results in reduction of the fracture callus and a delay in conversion of cartilage to bone. The signal(s) triggering expression of the pluripotency genes are unknown, but we demonstrate that endothelial cell conditioned medium upregulates these genes in ex vivo fracture cultures, supporting histological evidence that transdifferentiation occurs adjacent to the vasculature. Elucidating the cellular and molecular mechanisms underlying fracture repair is important for understanding why some fractures fail to heal and for developing novel therapeutic interventions. © 2017. Published by The Company of Biologists Ltd.

Anti-DKK1 antibody promotes bone fracture healing through activation of β-catenin signaling

PubMed Central

Jin, Hongting; Wang, Baoli; Li, Jia; Xie, Wanqing; Mao, Qiang; Li, Shan; Dong, Fuqiang; Sun, Yan; Ke, Hua-Zhu; Babij, Philip; Tong, Peijian; Chen, Di

2015-01-01

In this study we investigated if Wnt/β-catenin signaling in mesenchymal progenitor cells plays a role in bone fracture repair and if DKK1-Ab promotes fracture healing through activation of β-catenin signaling. Unilateral open transverse tibial fractures were created in CD1 mice and in β-cateninPrx1ER conditional knockout (KO) and Cre-negative control mice (C57BL/6 background). Bone fracture callus tissues were collected and analyzed by radiography, micro-CT (μCT), histology, biomechanical testing and gene expression analysis. The results demonstrated that treatment with DKK1-Ab promoted bone callus formation and increased mechanical strength during the fracture healing processinCD1 mice. DKK1-Ab enhanced fracture repair by activation of endochondral ossification. The normal rate of bone repair was delayed when the β-catenin gene was conditionally deleted in mesenchymal progenitor cells during the early stages of fracture healing. DKK1-Ab appeared to act through β-catenin signaling to enhance bone repair since the beneficial effect of DKK1-Ab was abrogated in β-cateninPrx1ER conditional KO mice. Further understanding of the signaling mechanism of DKK1-Ab in bone formation and bone regeneration may facilitate the clinical translation of this anabolic agent into therapeutic intervention. PMID:25263522

The effect of HIV on early wound healing in open fractures treated with internal and external fixation.

PubMed

Aird, J; Noor, S; Lavy, C; Rollinson, P

2011-05-01

There are 33 million people worldwide currently infected with human immunodeficiency virus (HIV). This complex disease affects many of the processes involved in wound and fracture healing, and there is little evidence available to guide the management of open fractures in these patients. Fears of acute and delayed infection often inhibit the use of fixation, which may be the most effective way of achieving union. This study compared fixation of open fractures in HIV-positive and -negative patients in South Africa, a country with very high rates of both HIV and high-energy trauma. A total of 133 patients (33 HIV-positive) with 135 open fractures fulfilled the inclusion criteria. This cohort is three times larger than in any similar previously published study. The results suggest that HIV is not a contraindication to internal or external fixation of open fractures in this population, as HIV is not a significant risk factor for acute wound/implant infection. However, subgroup analysis of grade I open fractures in patients with advanced HIV and a low CD4 count (< 350) showed an increased risk of infection; we suggest that grade I open fractures in patients with advanced HIV should be treated by early debridement followed by fixation at an appropriate time.

Nonsteroidal anti-inflammatory drug-induced fracture nonunion: an inhibition of angiogenesis?

PubMed

Murnaghan, Mark; Li, Gang; Marsh, David R

2006-11-01

Approximately 5% to 10% of fractures may result in delayed union or nonunion. The results of research done over the past three decades have shown that the use of nonsteroidal anti-inflammatory drugs (NSAIDs) has an inhibitory effect on fracture repair, but the exact mechanism of action remains to be elucidated. Cancer research has identified that NSAIDs impede cell proliferation by inhibiting angiogenesis. It is proposed that a similar mechanism occurs in the induction of NSAID-induced nonunions. This hypothesis was investigated in a randomized placebo-controlled trial of the NSAID rofecoxib with use of a murine femoral fracture model. Two hundred and forty mice were randomized to receive either the nonsteroidal anti-inflammatory drug rofecoxib (5 mg/kg orally) in a 0.5% methylcellulose solution (the NSAID group) or the 0.5% methylcellulose solution only (the control group). Two hundred and thirty-five of the 240 mice underwent surgery to induce an open transverse middiaphyseal femoral fracture, which was then treated with use of a custom-made external fixator. Five additional animals underwent sham surgery with no fracture induced. Outcomes measures included radiographic assessment, histologic analysis, biomechanical testing, and use of laser Doppler flowmetry to assess blood flow across the fracture gap. Radiography revealed similar healing patterns in both groups; however, at the later stages (day 32), the NSAID group had poorer healing. Histological analysis demonstrated that the control animals healed quicker (at days 24 and 32) and had more callus and less fibrous tissue (at days 8 and 32) than the NSAID animals did. Biomechanical testing found that the control animals were stronger at day 32. Both groups exhibited a similar pattern of blood flow; however, the NSAID group exhibited a lower median flow from day 4 onward (significant at days 4, 16, and 24). Positive correlations were demonstrated between both histological and radiographic assessments of healing and increasing blood flow. NSAID-treated animals exhibited lower blood flow and poorer healing by all parameters. Regression analysis, however, demonstrated that the negative effect of NSAIDs on fracture repair is independent of its inhibitory action on blood flow. Following the development of a novel method of analyzing functional vascularity across a fracture gap, we have demonstrated that the cyclooxygenase-2 (COX-2) inhibitor rofecoxib has a significant negative effect on blood flow across the fracture gap as well as an inhibiting effect on fracture repair. COX-2 inhibitors are marketed as having low side-effect profiles. We propose that these drugs should be used with caution in all patients following osseous trauma and, in particular, after injuries that may already predispose a fracture to a delayed union due to osseous, vascular, or patient-related factors.

The management of open tibial fractures in children: a retrospective case series of eight years' experience of 61 cases at a paediatric specialist centre.

PubMed

Nandra, R S; Wu, F; Gaffey, A; Bache, C E

2017-04-01

Following the introduction of national standards in 2009, most major paediatric trauma is now triaged to specialist units offering combined orthopaedic and plastic surgical expertise. We investigated the management of open tibia fractures at a paediatric trauma centre, primarily reporting the risk of infection and rate of union. A retrospective review was performed on 61 children who between 2007 and 2015 presented with an open tibia fracture. Their mean age was nine years (2 to 16) and the median follow-up was ten months (interquartile range 5 to 18). Management involved IV antibiotics, early debridement and combined treatment of the skeletal and soft-tissue injuries in line with standards proposed by the British Orthopaedic Association. There were 36 diaphyseal fractures and 25 distal tibial fractures. Of the distal fractures, eight involved the physis. Motor vehicle collisions accounted for two thirds of the injuries and 38 patients (62%) arrived outside of normal working hours. The initial method of stabilisation comprised: casting in nine cases (15%); elastic nailing in 19 (31%); Kirschner (K)-wiring in 13 (21%); intramedullary nailing in one (2%); open reduction and plate fixation in four (7%); and external fixation in 15 (25%). Wound management comprised: primary wound closure in 24 (39%), delayed primary closure in 11 (18%), split skin graft (SSG) in eight (13%), local flap with SSG in 17 (28%) and a free flap in one. A total of 43 fractures (70%) were Gustilo-Anderson grade III. There were four superficial (6.6%) and three (4.9%) deep infections. Two deep infections occurred following open reduction and plate fixation and the third after K-wire fixation of a distal fracture. No patient who underwent primary wound closure developed an infection. All the fractures united, although nine patients required revision of a mono-lateral to circular frame for delayed union (two) or for altered alignment or length (seven). The mean time to union was two weeks longer in diaphyseal fractures than in distal fractures (13 weeks versus 10.8 weeks, p = 0.016). Children aged > 12 years had a significantly longer time to union than those aged < 12 years (16.3 weeks versus 11.4 weeks, p = 0.045). The length of stay in hospital for patients with a Gustilo-Anderson grade IIIB fracture was twice as long as for less severe injuries. Fractures in children heal better than those in adults. Based on our experience of deep infection we discourage the use of internal fixation with a plate for open tibial fractures in children. We advocate aggressive initial wound debridement in theatre with early definitive combined orthopaedic and plastic surgery in order to obtain skeletal stabilisation and soft-tissue cover. Cite this article: Bone Joint J 2017;99-B:544-53. ©2017 The British Editorial Society of Bone & Joint Surgery.

Toughening Mechanisms in Nanolayered MAX Phase Ceramics—A Review

PubMed Central

Chen, Xinhua; Bei, Guoping

2017-01-01

Advanced engineering and functional ceramics are sensitive to damage cracks, which delay the wide applications of these materials in various fields. Ceramic composites with enhanced fracture toughness may trigger a paradigm for design and application of the brittle components. This paper reviews the toughening mechanisms for the nanolayered MAX phase ceramics. The main toughening mechanisms for these ternary compounds were controlled by particle toughening, phase-transformation toughening and fiber-reinforced toughening, as well as texture toughening. Based on the various toughening mechanisms in MAX phase, models of SiC particles and fibers toughening Ti3SiC2 are established to predict and explain the toughening mechanisms. The modeling work provides insights and guidance to fabricate MAX phase-related composites with optimized microstructures in order to achieve the desired mechanical properties required for harsh application environments. PMID:28772723

Investigation of post hydraulic fracturing well cleanup physics in the Cana Woodford Shale

NASA Astrophysics Data System (ADS)

Lu, Rong

Hydraulic fracturing was first carried out in the 1940s and has gained popularity in current development of unconventional resources. Flowing back the fracturing fluids is critical to a frac job, and determining well cleanup characteristics using the flowback data can help improve frac design. It has become increasingly important as a result of the unique flowback profiles observed in some shale gas plays due to the unconventional formation characteristics. Computer simulation is an efficient and effective way to tackle the problem. History matching can help reveal some mechanisms existent in the cleanup process. The Fracturing, Acidizing, Stimulation Technology (FAST) Consortium at Colorado School of Mines previously developed a numerical model for investigating the hydraulic fracturing process, cleanup, and relevant physics. It is a three-dimensional, gas-water, coupled fracture propagation-fluid flow simulator, which has the capability to handle commonly present damage mechanisms. The overall goal of this research effort is to validate the model on real data and to investigate the dominant physics in well cleanup for the Cana Field, which produces from the Woodford Shale in Oklahoma. To achieve this goal, first the early time delayed gas production was explained and modeled, and a simulation framework was established that included all three relevant damage mechanisms for a slickwater fractured well. Next, a series of sensitivity analysis of well cleanup to major reservoir, fracture, and operational variables was conducted; five of the Cana wells' initial flowback data were history matched, specifically the first thirty days' gas and water producing rates. Reservoir matrix permeability, net pressure, Young's modulus, and formation pressure gradient were found to have an impact on the gas producing curve's shape, in different ways. Some moderately good matches were achieved, with the outcome of some unknown reservoir information being proposed using the corresponding inputs from the history matching study. It was also concluded that extended shut-in durations after fracturing all the stages do not delay production in the overall situation. The success of history matching will further knowledge of well cleanup characteristics in the Cana Field, enable the future usage of this tool in other hydraulically fractured gas wells, and help operators optimize the flowback operations. Future improvements can be achieved by further developing the current simulator so that it has the capability of optimizing its grids setting every time the user changes the inputs, which will result in better stability when the relative permeability setting is modified.

Supination external rotation ankle fractures: A simpler pattern with better outcomes

PubMed Central

Tejwani, Nirmal C; Park, Ji Hae; Egol, Kenneth A

2015-01-01

Background: Rotational injuries are the most common and usually classified as per the Lauge Hansen classification; with the most common subgroup being the supination external rotation (SER) mechanism. Isolated fractures of the distal fibula (SE2) without associated ligamentous injury are usually treated with a splint or brace and the patient may be allowed to weight bear as tolerated. This study reports the functional outcomes following a stable, low energy, rotational ankle fracture supination external rotation (SER2) when compared to unstable SER4 fractures treated operatively. Materials and Methods: 64 patients who were diagnosed and treated nonoperatively for a stable SER2 ankle fracture were followed prospectively. In the comparison group, 93 operatively treated fibular fractures were extracted from a prospectively collected database and evaluated comparison. Baseline characteristics obtained by trained interviewers at the time of injury included: Patient demographics, short form-36, short musculoskeletal functional assessment (SMFA) and American Orthopedic Foot and Ankle Society (AOFAS) questionnaires. Patients were followed at 3, 6 and 12 months postsurgery. Additional information obtained at each followup point included any complications or evidence on fracture healing. Data were analyzed by the Student's t-test and theFisher's Exact Test to compare demographic and functional outcomes between the two cohorts. P < 0.05 was considered to be significant. Results: The average of patients’ age in the stable fracture cohort was 43 versus 45 in the SER4 group. Nearly 64% of the patient population was female when compared with 37% in the operative group. In the SER2 by 6 months all patients had returned to baseline functional status. There were 18 delayed unions (all healed by 6 months). Based on the functional outcome scores all patients had returned to preoperative level. In comparison, SE4 patients had less functional recovery at 3 and 6 months (P < 0.05) based on the SMFA scores and at 3, 6 and 12 months based on the AOFAS (P < 0.001) scores. There was no difference in pain levels between the two groups at all time points. There were three nonunions in the SE4 group and six delayed unions. Conclusions: An SER2 ankle fracture is a relatively benign injury with functional limitations resolving by 3 months while the need for surgical fixation in SER ankle fractures appears to affect lower extremity function to a greater degree for a longer time period. Patients should be counseled as to these expected outcomes. PMID:26015612

A visual servo-based teleoperation robot system for closed diaphyseal fracture reduction.

PubMed

Li, Changsheng; Wang, Tianmiao; Hu, Lei; Zhang, Lihai; Du, Hailong; Zhao, Lu; Wang, Lifeng; Tang, Peifu

2015-09-01

Common fracture treatments include open reduction and intramedullary nailing technology. However, these methods have disadvantages such as intraoperative X-ray radiation, delayed union or nonunion and postoperative rotation. Robots provide a novel solution to the aforementioned problems while posing new challenges. Against this scientific background, we develop a visual servo-based teleoperation robot system. In this article, we present a robot system, analyze the visual servo-based control system in detail and develop path planning for fracture reduction, inverse kinematics, and output forces of the reduction mechanism. A series of experimental tests is conducted on a bone model and an animal bone. The experimental results demonstrate the feasibility of the robot system. The robot system uses preoperative computed tomography data to realize high precision and perform minimally invasive teleoperation for fracture reduction via the visual servo-based control system while protecting surgeons from radiation. © IMechE 2015.

Gas gangrene in orthopaedic patients.

PubMed

Ying, Zhimin; Zhang, Min; Yan, Shigui; Zhu, Zhong

2013-01-01

Clostridial myonecrosis is most often seen in settings of trauma, surgery, malignancy, and other underlying immunocompromised conditions. Since 1953 cases of gas gangrene have been reported in orthopaedic patients including open fractures, closed fractures, and orthopaedic surgeries. We present a case of 55-year-old obese woman who developed rapidly progressive gas gangrene in her right leg accompanied by tibial plateau fracture without skin lacerations. She was diagnosed with clostridial myonecrosis and above-the-knee amputation was carried out. This patient made full recovery within three weeks of the initial episode. We identified a total of 50 cases of gas gangrene in orthopaedic patients. Several factors, if available, were analyzed for each case: age, cause of injury, fracture location, pathogen, and outcome. Based on our case report and the literature review, emergency clinicians should be aware of this severe and potentially fatal infectious disease and should not delay treatment or prompt orthopedic surgery consultation.

Gas Gangrene in Orthopaedic Patients

PubMed Central

Ying, Zhimin; Zhang, Min; Yan, Shigui; Zhu, Zhong

2013-01-01

Clostridial myonecrosis is most often seen in settings of trauma, surgery, malignancy, and other underlying immunocompromised conditions. Since 1953 cases of gas gangrene have been reported in orthopaedic patients including open fractures, closed fractures, and orthopaedic surgeries. We present a case of 55-year-old obese woman who developed rapidly progressive gas gangrene in her right leg accompanied by tibial plateau fracture without skin lacerations. She was diagnosed with clostridial myonecrosis and above-the-knee amputation was carried out. This patient made full recovery within three weeks of the initial episode. We identified a total of 50 cases of gas gangrene in orthopaedic patients. Several factors, if available, were analyzed for each case: age, cause of injury, fracture location, pathogen, and outcome. Based on our case report and the literature review, emergency clinicians should be aware of this severe and potentially fatal infectious disease and should not delay treatment or prompt orthopedic surgery consultation. PMID:24288638

Toxic shock syndrome post open reduction and Kirschner wire fixation of a humeral lateral condyle fracture

PubMed Central

Chan, Yuen; Selvaratnam, Veenesh; Garg, Neeraj

2015-01-01

Use of Kirschner wires (K-wires) is the most common method of fracture stabilisation in lateral condyle fracture fixation in children. We report a case of toxic shock syndrome (TSS) following an open reduction and internal fixation using K-wires for a humeral lateral condyle fracture in a 5-year-old girl. TSS is a toxin-mediated multisystem illness. It typically presents with shock and it is most often attributed to toxin-producing strains of Staphylococcus aureus and Streptococcus pyogenes. It can lead to multiorgan failure and, ultimately, death. It is important to be aware of TSS, as it can present within any setting. Patients often have non-specific symptoms and their condition can worsen rapidly. TSS postorthopaedic surgery is rare; however, due to the serious nature of this disease, it is important to promptly recognise and diagnose TSS, and to ensure appropriate treatment is started without delay. PMID:26264942

Should plain X-rays be routinely performed after blunt knee trauma? A prospective analysis.

PubMed

Jenny, Jean-Yves; Boeri, Cyril; El Amrani, Hakima; Dosch, Jean-Claude; Dupuis, Michel; Moussaoui, Akli; Mairot, Fabrice

2005-06-01

We tested the hypothesis that it was possible to decrease the number of performed x-rays after a knee trauma without delayed fracture diagnosis by using the Ottawa knee rules. Patients had routine x-rays of the injured knee during the first stage of the study and selective x-rays during the second stage. All patients were followed up to 6 months after the trauma. 138 patients were included in the first stage; 57 had negative Ottawa criteria: no fracture was observed; following the Ottawa rules, 41% of the x-rays could have been avoided. 178 patients were included in the second stage; 63 patients had negative Ottawa criteria: no fracture was diagnosed during the whole follow-up; 35% of the x-rays have been avoided. Ottawa rules allowed decreasing the number of x-rays performed after a knee trauma by 35% with a sensitivity for a knee fracture detection of 100%.

Hydraulic fracture propagation modeling and data-based fracture identification

NASA Astrophysics Data System (ADS)

Zhou, Jing

Successful shale gas and tight oil production is enabled by the engineering innovation of horizontal drilling and hydraulic fracturing. Hydraulically induced fractures will most likely deviate from the bi-wing planar pattern and generate complex fracture networks due to mechanical interactions and reservoir heterogeneity, both of which render the conventional fracture simulators insufficient to characterize the fractured reservoir. Moreover, in reservoirs with ultra-low permeability, the natural fractures are widely distributed, which will result in hydraulic fractures branching and merging at the interface and consequently lead to the creation of more complex fracture networks. Thus, developing a reliable hydraulic fracturing simulator, including both mechanical interaction and fluid flow, is critical in maximizing hydrocarbon recovery and optimizing fracture/well design and completion strategy in multistage horizontal wells. A novel fully coupled reservoir flow and geomechanics model based on the dual-lattice system is developed to simulate multiple nonplanar fractures' propagation in both homogeneous and heterogeneous reservoirs with or without pre-existing natural fractures. Initiation, growth, and coalescence of the microcracks will lead to the generation of macroscopic fractures, which is explicitly mimicked by failure and removal of bonds between particles from the discrete element network. This physics-based modeling approach leads to realistic fracture patterns without using the empirical rock failure and fracture propagation criteria required in conventional continuum methods. Based on this model, a sensitivity study is performed to investigate the effects of perforation spacing, in-situ stress anisotropy, rock properties (Young's modulus, Poisson's ratio, and compressive strength), fluid properties, and natural fracture properties on hydraulic fracture propagation. In addition, since reservoirs are buried thousands of feet below the surface, the parameters used in the reservoir flow simulator have large uncertainty. Those biased and uncertain parameters will result in misleading oil and gas recovery predictions. The Ensemble Kalman Filter is used to estimate and update both the state variables (pressure and saturations) and uncertain reservoir parameters (permeability). In order to directly incorporate spatial information such as fracture location and formation heterogeneity into the algorithm, a new covariance matrix method is proposed. This new method has been applied to a simplified single-phase reservoir and a complex black oil reservoir with complex structures to prove its capability in calibrating the reservoir parameters.

Fracture toughness, diametrical strength, and fractography of amalgam and of amalgam to amalgam bonds.

PubMed

Bapna, M S; Mueller, H J

1993-01-01

Chevron-notch fracture toughness, diametrical tensile strength and fractography were evaluated for bulk amalgams and for bonds formed between new and 1-day-old amalgams of the same type. Three types of bonded specimens were prepared: 1) by mechanically roughening the 1-day-old amalgam with 600-grit paper; 2) using a new mercury-rich amalgam; and 3) using a bonding resin, either 4-META or a phosphate ester monomer. Similar values in bond properties were obtained with all bonding techniques for two commercial dispersed-phase bonded amalgams, one of which contained palladium; however, bulk fracture toughness of the palladium-containing amalgam was significantly less than for the palladium-free amalgam. This result reveals that the bonding of amalgam to amalgam, at least for these two amalgams, is a surface-related phenomenon, and thus, the traditional reporting of bonding properties as a percentage of bulk properties loses meaning. Short-rod geometry was more representative of the interfacial bond properties since these samples fractured within the interfacial bonds, while diametrical strength samples often fractured slightly away from the interface. The use of bonding resins did not improve bond fracture toughness for either amalgam, while the diametrical strength improved for one of the amalgams. The use of mercury-rich amalgam significantly improved the fracture toughness over all other techniques for one amalgam while proving to be similar to a 600-grit preparation for the second amalgam.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of the flow property of aluminum alloy AA6016 based on the fracture morphology using the hydroforming technology

NASA Astrophysics Data System (ADS)

Lang, Lihui; Zhang, Quanda; Sun, Zhiying; Wang, Yao

2017-09-01

In this paper, the hydraulic bulging experiments were respectively carried out using AA6016-T4 aluminum alloy and AA6016-O aluminum alloy, and the deformation properties and fracture mechanism of aluminum alloy under the conditions of thermal and hydraulic were analyzed. Firstly, the aluminum alloy AA6016 was dealt with two kinds of heat treatment systems such as solid solution heat treatment adding natural ageing and full annealing, then the aluminum alloy such as AA6016-T4 and AA6016-O were obtained. In the same working environment, the two kinds of materials were used in the process of hydraulic bulging experiments, according to the observation and measurement of the deformation sizes of grid circles and material thicknesses near the fracture region, the flow properties and development trend of fracture defect of the materials were analyzed comprehensively from the perspective of qualitative analysis and quantitative analysis; Secondly, the two kinds of materials were sampled in different regions of the fracture area and the microstructure morphology of the fracture was observed by the scanning electron microscope (SEM). The influence laws of the heat treatment systems on the fracture defect of the aluminum alloy under the condition of the liquid pressure were studied preliminarily by observing the distribution characteristics of the fracture microstructure morphology of dimple. At the same time, the experimental research on the ordinary stamping forming process of AA6016-O was carried out and the influence law of different forming process on the fracture defect of the aluminum alloy material was studied by observing the distribution of the fracture microstructure morphology; Finally, the development process of the fracture defect of aluminum alloy sheet was described theoretically from the view of the stress state.

Women with previous stress fractures show reduced bone material strength

PubMed Central

Duarte Sosa, Daysi; Fink Eriksen, Erik

2016-01-01

Background and purpose — Bone fragility is determined by bone mass, bone architecture, and the material properties of bone. Microindentation has been introduced as a measurement method that reflects bone material properties. The pathogenesis of underlying stress fractures, in particular the role of impaired bone material properties, is still poorly understood. Based on the hypothesis that impaired bone material strength might play a role in the development of stress fractures, we used microindentation in patients with stress fractures and in controls. Patients and methods — We measured bone material strength index (BMSi) by microindentation in 30 women with previous stress fractures and in 30 normal controls. Bone mineral density by DXA and levels of the bone markers C-terminal cross-linking telopeptide of type-1 collagen (CTX) and N-terminal propeptide of type-1 procollagen (P1NP) were also determined. Results — Mean BMSi in stress fracture patients was significantly lower than in the controls (SD 72 (8.7) vs. 77 (7.2); p = 0.02). The fracture subjects also had a significantly lower mean bone mineral density (BMD) than the controls (0.9 (0.02) vs. 1.0 (0.06); p = 0.03). Bone turnover—as reflected in serum levels of the bone marker CTX—was similar in both groups, while P1NP levels were significantly higher in the women with stress fractures (55 μg/L vs. 42 μg/L; p = 0.03). There was no correlation between BMSi and BMD or bone turnover. Interpretation — BMSi was inferior in patients with previous stress fracture, but was unrelated to BMD and bone turnover. The lower values of BMSi in patients with previous stress fracture combined with a lower BMD may contribute to the increased propensity to develop stress fractures in these patients. PMID:27321443

Thermophysics of fractures on comet 67P/Churyumov-Gerasimenko

NASA Astrophysics Data System (ADS)

Höfner, S.; Vincent, J.-B.; Blum, J.; Davidsson, B. J. R.; Sierks, H.; El-Maarry, M. R.; Deller, J.; Hofmann, M.; Hu, X.; Pajola, M.; Barbieri, C.; Lamy, P. L.; Rodrigo, R.; Koschny, D.; Rickman, H.; Keller, H. U.; A'Hearn, M. F.; Auger, A.-T.; Barucci, M. A.; Bertaux, J.-L.; Bertini, I.; Bodewits, D.; Cremonese, G.; Da Deppo, V.; Debei, S.; De Cecco, M.; Fornasier, S.; Fulle, M.; Gicquel, A.; Groussin, O.; Gutiérrez, P. J.; Gutiérrez-Marqués, P.; Güttler, C.; Hviid, S. F.; Ip, W.-H.; Jorda, L.; Knollenberg, J.; Kovacs, G.; Kramm, J.-R.; Kührt, E.; Küppers, M.; La Forgia, F.; Lazzarin, M.; Lopez-Moreno, J. J.; Marzari, F.; Michalik, H.; Moissl-Fraund, R.; Moreno, F.; Mottola, S.; Naletto, G.; Oklay, N.; Preusker, F.; Scholten, F.; Shi, X.; Thomas, N.; Toth, I.; Tubiana, C.; Zitzmann, S.

2017-12-01

Context. The camera OSIRIS on board Rosetta obtained high-resolution images of the nucleus of comet 67P/Churyumov-Gerasimenko (67P). Great parts of the nucleus surface are composed of fractured terrain. Aims: Fracture formation, evolution, and their potential relationship to physical processes that drive activity are not yet fully understood. Observed temperatures and gas production rates can be explained or interpreted with the presence of fractures by applying appropriate modelling methods. Methods: We followed a transient thermophysical model approach that includes radiative, conductive, and water-ice sublimation fluxes by considering a variety of heliocentric distances, illumination conditions, and thermophysical properties for a set of characteristic fracture geometries on the nucleus of 67P. We computed diurnal temperatures, heat fluxes, and outgassing behaviour in order to derive and distinguish the influence of the mentioned parameters on fractured terrain. Results: Our analysis confirms that fractures, as already indicated by former studies about concavities, deviate from flat-terrain topographies with equivalent properties, mostly through the effect of self-heating. Compared to flat terrain, illuminated cometary fractures are generally warmer, with smaller diurnal temperature fluctuations. Maximum sublimation rates reach higher peaks, and dust mantle quenching effects on sublimation rates are weaker. Consequently, the rough structure of the fractured terrain leads to significantly higher inferred surface thermal inertia values than for flat areas with identical physical properties, which might explain the range of measured thermal inertia on 67P. Conclusions: At 3.5 AU heliocentric distance, sublimation heat sinks in fractures converge to maximum values >50 W / m2 and trigger dust activity that can be related mainly to H2O. Fractures are likely to grow through the erosive interplay of alternating sublimation and thermal fatigue.

Numerical Simulation of Tension Properties for Al-Cu Alloy Friction Stir-Welded Joints with GTN Damage Model

NASA Astrophysics Data System (ADS)

Sun, Guo-Qin; Sun, Feng-Yang; Cao, Fang-Li; Chen, Shu-Jun; Barkey, Mark E.

2015-11-01

The numerical simulation of tensile fracture behavior on Al-Cu alloy friction stir-welded joint was performed with the Gurson-Tvergaard-Needleman (GTN) damage model. The parameters of the GTN model were studied in each region of the friction stir-welded joint by means of inverse identification. Based on the obtained parameters, the finite element model of the welded joint was built to predict the fracture behavior and tension properties. Good agreement can be found between the numerical and experimental results in the location of the tensile fracture and the mechanical properties.

Development of an injectable pseudo-bone thermo-gel for application in small bone fractures.

PubMed

Kondiah, Pariksha J; Choonara, Yahya E; Kondiah, Pierre P D; Kumar, Pradeep; Marimuthu, Thashree; du Toit, Lisa C; Pillay, Viness

2017-03-30

A pseudo-bone thermo-gel was synthesized and evaluated for its physicochemical, mechanical and rheological properties, with its application to treat small bone fractures. The pseudo-bone thermo-gel was proven to have thermo-responsive properties, behaving as a solution in temperatures below 25°C, and forming a gelling technology when maintained at physiological conditions. Poly propylene fumerate (PPF), Pluronic F127 and PEG-PCL-PEG were strategically blended, obtaining a thermo-responsive delivery system, to mimic the mechanical properties of bone with sufficient matrix hardness and resilience. A Biopharmaceutics Classification System (BCS) class II drug, simvastatin, was loaded in the pseudo-bone thermo-gel, selected for its bone healing properties. In vitro release analysis was undertaken on a series of experimental formulations, with the ideal formulations obtaining its maximum controlled drug release profile up to 14days. Ex vivo studies were undertaken on an induced 4mm diameter butterfly-fractured osteoporotic human clavicle bone samples. X-ray, ultrasound as well as textural analysis, undertaken on the fractured bones before and after treatment displayed significant bone filling, matrix hardening and matrix resilience properties. These characteristics of the pseudo-bone thermo-gel thus proved significant potential for application in small bone fractures. Copyright © 2017 Elsevier B.V. All rights reserved.

Fracture Toughness to Understand Stretch-Flangeability and Edge Cracking Resistance in AHSS

NASA Astrophysics Data System (ADS)

Casellas, Daniel; Lara, Antoni; Frómeta, David; Gutiérrez, David; Molas, Sílvia; Pérez, Lluís; Rehrl, Johannes; Suppan, Clemens

2017-01-01

The edge fracture is considered as a high risk for automotive parts, especially for parts made of advanced high strength steels (AHSS). The limited ductility of AHSS makes them more sensitive to the edge damage. The traditional approaches, such as those based on ductility measurements or forming limit diagrams, are unable to predict this type of fractures. Thus, stretch-flangeability has become an important formability parameter in addition to tensile and formability properties. The damage induced in sheared edges in AHSS parts affects stretch-flangeability, because the generated microcracks propagate from the edge. Accordingly, a fracture mechanics approach may be followed to characterize the crack propagation resistance. With this aim, this work addresses the applicability of fracture toughness as a tool to understand crack-related problems, as stretch-flangeability and edge cracking, in different AHSS grades. Fracture toughness was determined by following the essential work of fracture methodology and stretch-flangeability was characterized by means of hole expansions tests. Results show a good correlation between stretch-flangeability and fracture toughness. It allows postulating fracture toughness, measured by the essential work of fracture methodology, as a key material property to rationalize crack propagation phenomena in AHSS.

Intramedullary compression arthrodesis of the knee: early experience with a new device and technique.

PubMed

McQueen, David A; Cooke, Francis W; Hahn, Dustan L

2005-01-01

The irretrievably failed total knee arthroplasty is the primary indication for knee arthrodesis. Because this difficult condition is relatively rare, an intramedullary arthrodesis system was developed which requires minimal surgeon experience for successful use. The new system called the Wichita Fusion Nail was implanted by a single surgeon in 13 consecutive patients: 11 for arthrodesis alone, 1 for stabilization of a supracondylar fracture nonunion, and 1 for arthrodesis coupled with a supracondylar fracture nonunion. All arthrodesis attempts were successful. The average fusion time was 15.2 weeks except for 2 infected delayed arthrodeses. Both fracture nonunions persisted and went on to amputation. The WFN provides a simple arthrodesis system with minimal technique dependence and a high potential for success.

Cerebral fat embolism syndrome causing brain death after long-bone fractures and acetazolamide therapy.

PubMed

Walshe, Criona M; Cooper, James D; Kossmann, Thomas; Hayes, Ivan; Iles, Linda

2007-06-01

A 19-year-old woman with multiple fractures and mild brain injury developed severe cerebral fat embolism syndrome after "damage control" orthopaedic surgery. Acetazolamide therapy to manage ocular trauma, in association with hyperchloraemia, caused a profound metabolic acidosis with appropriate compensatory hypocapnia. During ventilator weaning, unexpected brainstem coning followed increased sedation and brief normalisation of arterial carbon dioxide concentration. Autopsy found severe cerebral fat embolism and brain oedema. In patients with multiple trauma, cerebral fat embolism syndrome is difficult to diagnose, and may be more common after delayed fixation of long-bone fractures. Acetazolamide should be used with caution, as sudden restoration of normocapnia during compensated metabolic acidosis in patients with raised intracranial pressure may precipitate coning.

Formulation and Physical Properties of Cyanate Ester Nanocomposites Based on Graphene

DTIC Science & Technology

2014-03-01

during cure. The addition of GO, and, to a lesser extent, TRGO, resulted in improved mechanical properties, particularly fracture toughness, with the...a lesser extent, TRGO, resulted in improved mechanical proper- ties, particularly fracture toughness, with the addition of TRGO having a modestly...LECy. However, the mechanism of fracture toughness improvement may be different with each form of graphene. In the case of GO, the high degree of oxi

Treatment of type II and type III open tibia fractures in children.

PubMed

Bartlett, C S; Weiner, L S; Yang, E C

1997-07-01

To determine whether severe open tibial fractures in children behave like similar fractures in adults. A combined retrospective and prospective review evaluated treatment protocol for type II and type III open tibial fractures in children over a ten-year period from 1984 to 1993. Twenty-three fractures were studied in children aged 3.5 to 14.5 (18 boys and 5 girls). There were six type II, eight type IIIA, and nine type IIIB fractures. Type I fractures were not included. Seven fractures were comminuted with significant butterfly fragments or segmental patterns. Treatment consisted of adequate debridement of soft tissues, closure of dead space, and stabilization with external fixation. Bone debridement only included contaminated devitalized bone or devitalized bone without soft tissue coverage. Bone that could be covered despite periosteal stripping was preserved. Clinical and roentgenographic examinations were used to determine time to union. All fractures in this series healed between eight and twenty-six weeks. Wound coverage included two flaps, three skin grafts, and two delayed primary closures. No bone grafts were required. There were no deep infections, growth arrests, or malunions. Follow-up has ranged from six months to four years. Open tibia fractures in children differ from similar fractures in adults in the following ways: soft tissues have excellent healing capacity, devitalized bone that is not contaminated or exposed can be saved and will become incorporated, and external fixation can be maintained until the fracture has healed. Periosteum in young children can form bone even in the face of bone loss.

Immature myeloid cells are critical for enhancing bone fracture healing through angiogenic cascade

PubMed Central

Levy, Seth; Feduska, Joseph M.; Sawant, Anandi; Gilbert, Shawn; Hensel, Jonathan A.; Ponnazhagan, Selvarangan

2016-01-01

Bone fractures heal with overlapping phases of inflammation, cell proliferation, and bone remodeling. Osteogenesis and angiogenesis work in concert to control many stages of this process, and when one is impaired it leads to failure of bone healing, termed a nonunion. During fracture repair, there is an infiltration of immune cells at the fracture site that not only mediate the inflammatory responses, but we hypothesize they also exert influence on neovasculature. Thus, further understanding the effects of immune cell participation throughout fracture healing will reveal additional knowledge as to why some fractures heal while others form nonunions, and lead to development of novel therapeutics modulating immune cells, to increase fracture healing and prevent nonunions. Using novel femoral segmental and critical-size defect models in mice, we identified a systemic and significant increase in immature myeloid cell (IMC) infiltration during the initial phase of fracture healing until boney union is complete. Using gemcitabine to specifically ablate the IMC population, we confirmed delayed bone healing. Further, adoptive transfer of IMC increased bone growth in a nonunion model, signifying the role of this unique cell population in fracture healing. We also identified IMC post-fracture have the ability to increase endothelial cell migration, and tube formation, signaling the essential communication between the immune system and angiogenesis as a requirement for proper bone healing. Based on this data we propose that IMC may play a significant role in fracture healing and therapeutic targeting of IMC after fracture would minimize the chances of eventual nonunion pathology. PMID:27664567

Immature myeloid cells are critical for enhancing bone fracture healing through angiogenic cascade.

PubMed

Levy, Seth; Feduska, Joseph M; Sawant, Anandi; Gilbert, Shawn R; Hensel, Jonathan A; Ponnazhagan, Selvarangan

2016-12-01

Bone fractures heal with overlapping phases of inflammation, cell proliferation, and bone remodeling. Osteogenesis and angiogenesis work in concert to control many stages of this process, and when one is impaired it leads to failure of bone healing, termed a nonunion. During fracture repair, there is an infiltration of immune cells at the fracture site that not only mediate the inflammatory responses, but we hypothesize they also exert influence on neovasculature. Thus, further understanding the effects of immune cell participation throughout fracture healing will reveal additional knowledge as to why some fractures heal while others form nonunions, and lead to development of novel therapeutics modulating immune cells, to increase fracture healing and prevent nonunions. Using novel femoral segmental and critical-size defect models in mice, we identified a systemic and significant increase in immature myeloid cell (IMC) infiltration during the initial phase of fracture healing until boney union is complete. Using gemcitabine to specifically ablate the IMC population, we confirmed delayed bone healing. Further, adoptive transfer of IMC increased bone growth in a nonunion model, signifying the role of this unique cell population in fracture healing. We also identified IMC post-fracture have the ability to increase endothelial cell migration, and tube formation, signaling the essential communication between the immune system and angiogenesis as a requirement for proper bone healing. Based on this data we propose that IMC may play a significant role in fracture healing and therapeutic targeting of IMC after fracture would minimize the chances of eventual nonunion pathology. Copyright © 2016 Elsevier Inc. All rights reserved.

3D Modeling and Characterization of Hydraulic Fracture Efficiency Integrated with 4D/9C Time-Lapse Seismic Interpretations in the Niobrara Formation, Wattenberg Field, Denver Basin

NASA Astrophysics Data System (ADS)

Alfataierge, Ahmed

Hydrocarbon recovery rates within the Niobrara Shale are estimated as low as 2-8%. These recovery rates are controlled by the ability to effectively hydraulic fracture stimulate the reservoir using multistage horizontal wells. Subsequent to any mechanical issues that affect production from lateral wells, the variability in production performance and reserve recovery along multistage lateral shale wells is controlled by the reservoir heterogeneity and its consequent effect on hydraulic fracture stimulation efficiency. Using identical stimulation designs on a number of wells that are as close as 600ft apart can yield variable production and recovery rates due to inefficiencies in hydraulic fracture stimulation that result from the variability in elastic rock properties and in-situ stress conditions. As a means for examining the effect of the geological heterogeneity on hydraulic fracturing and production within the Niobrara Formation, a 3D geomechanical model is derived using geostatistical methods and volumetric calculations as an input to hydraulic fracture stimulation. The 3D geomechanical model incorporates the faults, lithological facies changes and lateral variation in reservoir properties and elastic rock properties that best represent the static reservoir conditions pre-hydraulic fracturing. Using a 3D numerical reservoir simulator, a hydraulic fracture predictive model is generated and calibrated to field diagnostic measurements (DFIT) and observations (microseismic and 4D/9C multicomponent time-lapse seismic). By incorporating the geological heterogeneity into the 3D hydraulic fracture simulation, a more representative response is generated that demonstrate the variability in hydraulic fracturing efficiency along the lateral wells that will inevitability influence production performance. Based on the 3D hydraulic fracture simulation results, integrated with microseismic observations and 4D/9C time-lapse seismic analysis (post-hydraulic fracturing & post production), the variability in production performance within the Niobrara Shale wells is shown to significantly be affected by the lateral variability in reservoir quality, well and stage positioning relative to the target interval, and the relative completion efficiency. The variation in reservoir properties, faults, rock strength parameters, and in-situ stress conditions are shown to influence and control the hydraulic fracturing geometry and stimulation efficiency resulting in complex and isolated induced fracture geometries to form within the reservoir. This consequently impacts the effective drainage areas, production performance and recovery rates from inefficiently stimulated horizontal wells. The 3D simulation results coupled with the 4D seismic interpretations illustrate that there is still room for improvement to be made in optimizing well spacing and hydraulic fracturing efficiency within the Niobrara Formation. Integrated analysis show that the Niobrara reservoir is not uniformly stimulated. The vertical and lateral variability in rock properties control the hydraulic fracturing efficiency and geometry. Better production is also correlated to higher fracture conductivity. 4D seismic interpretation is also shown to be essential for the validation and calibration hydraulic fracture simulation models. The hydraulic fracture modeling also demonstrations that there is bypassed pay in the Niobrara B chalk resulting from initial Niobrara C chalk stimulation treatments. Forward modeling also shows that low pressure intervals within the Niobrara reservoir influence hydraulic fracturing and infill drilling during field development.

Identification of Flaws Responsible for Crack Initiation and Micromechanisms of Slow Crack Growth in the Delayed Fracture of Alumina.

DTIC Science & Technology

1982-02-01

ntsitycrOtained Alumina in 50 % Relative Humidity . 123 (1) the material constants under a certain environment, A, B, and n in eq. (2-14) and eq. (2-15), evalu... Fatigue Crack Growth," Int. Jour. Fract., 17 (1981) 235-247. 3. S.M. Wiederhorn, " Effects of Environment on the Fracture of Glass," Environment-Sensitive...Distribution of Alumina 4 1 34 2-11 Schematic Drawing of Variation in Effective Critical Stress Intensity Factor, KC ff with Crack Length Relative to Grain

Fracture characterization from near-offset VSP inversion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Horne, S.; MacBeth, C.; Queen, J.

1997-01-01

A global optimization method incorporating a ray-tracing scheme is used to invert observations of shear-wave splitting from two near-offset VSPs recorded at the Conoco Borehole Test Facility, Kay County, Oklahoma. Inversion results suggest that the seismic anisotropy is due to a non-vertical fracture system. This interpretation is constrained by the VSP acquisition geometry for which two sources are employed along near diametrically opposite azimuths about the well heads. A correlation is noted between the time-delay variations between the fast and slow split shear waves and the sandstone formations.

Using borehole geophysics and cross-borehole flow testing to define hydraulic connections between fracture zones in bedrock aquifers

USGS Publications Warehouse

Paillet, Frederick L.

1993-01-01

Nearly a decade of intensive geophysical logging at fractured rock hydrology research sites indicates that geophysical logs can be used to identify and characterize fractures intersecting boreholes. However, borehole-to-borehole flow tests indicate that only a few of the apparently open fractures found to intersect boreholes conduct flow under test conditions. This paper presents a systematic approach to fracture characterization designed to define the distribution of fractures along boreholes, relate the measured fracture distribution to structure and lithology of the rock mass, and define the nature of fracture flow paths across borehole arrays. Conventional electrical resistivity, gamma, and caliper logs are used to define lithology and large-scale structure. Borehole wall image logs obtained with the borehole televiewer are used to give the depth, orientation, and relative size of fractures in situ. High-resolution flowmeter measurements are used to identify fractures conducting flow in the rock mass adjacent to the boreholes. Changes in the flow field over time are used to characterize the hydraulic properties of fracture intersections between boreholes. Application of this approach to an array of 13 boreholes at the Mirror Lake, New Hamsphire site demonstrates that the transient flow analysis can be used to distinguish between fractures communicating with each other between observation boreholes, and those that are hydraulically isolated from each other in the surrounding rock mass. The Mirror Lake results also demonstrate that the method is sensitive to the effects of boreholes on the hydraulic properties of the fractured-rock aquifer. Experiments conducted before and after the drilling of additional boreholes in the array and before and after installation of packers in existing boreholes demonstrate that the presence of new boreholes or the inflation of packers in existing boreholes has a large effect on the measured hydraulic properties of the rock mass surrounding the borehole array. ?? 1993.

P-wave velocity anisotropy related to sealed fractures reactivation tracing the structural diagenesis in carbonates

NASA Astrophysics Data System (ADS)

Matonti, C.; Guglielmi, Y.; Viseur, S.; Garambois, S.; Marié, L.

2017-05-01

Fracture properties are important in carbonate reservoir characterization, as they are responsible for a large part of the fluid transfer properties at all scales. It is especially true in tight rocks where the matrix transfer properties only slightly contribute to the fluid flow. Open fractures are known to strongly affect seismic velocities, amplitudes and anisotropy. Here, we explore the impact of fracture evolution on the geophysical signature and directional Vp anisotropy of fractured carbonates through diagenesis. For that purpose, we studied a meter-scale, parallelepiped quarry block of limestone using a detailed structural and diagenetic characterization, and numerous Vp measurements. The block is affected by two en-échelon fracture clusters, both being formed in opening mode (mode 1) and cemented, but only one being reactivated in shear. We compared the diagenetic evolution of the fractures, which are almost all 100% filled with successive calcite cements, with the P-wave velocities measured across this meter-scale block of carbonate, which recorded the tectonic and diagenetic changes of a South Provence sedimentary basin. We found that a directional Vp anisotropy magnitude as high as 8-16% correlates with the reactivated fractures' cluster dip angle, which is explained by the complex filling sequence and softer material present inside the fractures that have been reactivated during the basin's tectonic inversion. We show that although a late karstification phase preferentially affected these reactivated fractures, it only amplified the pre-existing anisotropy due to tectonic shear. We conclude that Vp anisotropy measurements may help to identify the fracture sealing/opening processes associated with polyphased tectonic history, the anisotropy being independent of the current stress-state. This case shows that velocity anisotropies induced by fractures resulted here from a cause that is different from how these features have often been interpreted: selective reactivation of sealed fractures clusters rather than direction of currently open ones.

Role of Fas and Treg Cells in Fracture Healing as Characterized in the Fas-Deficient (lpr) Mouse Model of Lupus†

PubMed Central

Al-Sebaei, Maisa O; Daukss, Dana M; Belkina, Anna C; Kakar, Sanjeev; Wigner, Nathan A; Cusher, Daniel; Graves, Dana; Einhorn, Thomas; Morgan, Elise; Gerstenfeld, Louis C

2014-01-01

Previous studies showed that loss of tumor necrosis factor α (TNFα) signaling delayed fracture healing by delaying chondrocyte apoptosis and cartilage resorption. Mechanistic studies showed that TNFα induced Fas expression within chondrocytes; however, the degree to which chondrocyte apoptosis is mediated by TNFα alone or dependent on the induction of Fas is unclear. This question was addressed by assessing fracture healing in Fas-deficient B6.MRL/Faslpr/J mice. Loss of Fas delayed cartilage resorption but also lowered bone fraction in the calluses. The reduced bone fraction was related to elevated rates of coupled bone turnover in the B6.MRL/Faslpr/J calluses, as evidenced by higher osteoclast numbers and increased osteogenesis. Analysis of the apoptotic marker caspase 3 showed fewer positive chondrocytes and osteoclasts in calluses of B6.MRL/Faslpr/J mice. To determine if an active autoimmune state contributed to increased bone turnover, the levels of activated T cells and Treg cells were assessed. B6.MRL/Faslpr/J mice had elevated Treg cells in both spleens and bones of B6.MRL/Faslpr/J but decreased percentage of activated T cells in bone tissues. Fracture led to ∼30% to 60% systemic increase in Treg cells in both wild-type and B6.MRL/Faslpr/J bone tissues during the period of cartilage formation and resorption but either decreased (wild type) or left unchanged (B6.MRL/Faslpr/J) the numbers of activated T cells in bone. These results show that an active autoimmune state is inhibited during the period of cartilage resorption and suggest that iTreg cells play a functional role in this process. These data show that loss of Fas activity specifically in chondrocytes prolonged the life span of chondrocytes and that Fas synergized with TNFα signaling to mediate chondrocyte apoptosis. Conversely, loss of Fas systemically led to increased osteoclast numbers during later periods of fracture healing and increased osteogenesis. These findings suggest that retention of viable chondrocytes locally inhibits osteoclast activity or matrix proteolysis during cartilage resorption. © 2014 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research. PMID:24677136

Effect of water on mechanical properties and stress corrosion behavior of alloy 600, alloy 690, EN82H welds, and EN52 welds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, C.M.; Mills, W.J.

1999-02-01

The fracture toughness and tensile properties of alloy 600 (UNS N06600), alloy 690 (UNS N06690), and their welds (EN82H [UNS N06082] and EN52 [UNS N06052]) were characterized in 54 C and 338 C water with an elevated hydrogen content. Results were compared with air data to evaluate the effect of low- and high-temperature water on the mechanical properties. In addition, the stress corrosion cracking (SCC) behavior of EN82H and EN52 welds was evaluated in 360 C water. Elastic-plastic (J{sub IC}) fracture toughness testing revealed that the fracture resistance of all test materials was exceptionally high in 54 C and 338more » C air and 338 C water, demonstrating that fracture properties essentially were unaffected by the high-temperature water environment. In 54 C water, however, J{sub IC} values for EN82H and EN52 welds were reduced by an order of magnitude, and alloy 690 showed a fivefold decrease in J{sub IC}. Scanning electron fractography revealed that the degraded fracture properties were associated with a fracture mechanism transition from ductile dimple rupture to intergranular cracking. The latter was associated with hydrogen-induced cracking mechanism. The fracture toughness for alloy 600 remained high in 54 C water, and microvoid coalescence was the operative mechanism in low-temperature air and water. Tensile properties for all test materials essentially were unaffected by the water environment, except for the total elongation for EN82H welds, which was reduced significantly in 54 C water. Constant-load testing of precracked weld specimens in 360 C water resulted in extensive intergranular SCC in EN82H welds, whereas no SCC occurred in EN52 welds under comparable test conditions.« less

Constraining the Dynamic Rupture Properties with Moment Tensor Derived Vp/Vs Ratios.

NASA Astrophysics Data System (ADS)

Smith-Boughner, L.; Baig, A. M.; Urbancic, T.; Viegas, G. F.

2014-12-01

The goal of hydraulic fracturing is to increase the permeability of rocks to extract hydrocarbons from "tight" formations. This process stimulates fluid-driven fractures which induce microseismic events. Successfully treating the formations, stimulating large volumes of the reservoir, depends on targeting parts of the formation with more "brittleness", a property which is frequently characterized from the mechanical properties of the rock. Typically, these properties are constrained using well-logs, vertical seismic profiles and 3-D seismic surveys. Such tools provide a static view of the reservoir on very large or very small scales. While lithology controls the average rock strength within a unit, the content (gas or fluid filled), the shape of the pore space and the concentration of micro-fractures alters the mechanical properties of the reservoir. Seismic moment tensor inversion of the events generated during these stimulations reveals that they are significantly non-double-couple, and are described by a tensile angle and a Poisson's ratio (or, equivalently, ratio of shear to compressional velocities, Vp/Vs) of the rock-fracture system. Following Vavryčuk (2011), the mechanical properties of the reservoir (i.e. Vp/Vs ratio) are estimated as the hydraulic fracture progresses from an extensive catalog of microseismic events spanning magnitudes of -1.5 to 0.8 in the Horn-River Basin, Canada. Studying several fracture stages in the reservoir reveals temporal and spatial variations in the rock strength within a unit as hydraulic fracturing proceeds. Initially, the estimated values of Vp/Vs are quite close to those determined from 3-D seismic surveys. As the stage progresses, previously fractured regions have lower Vp/Vs values. At the onset of maximum treating pressure, regions have anomalously high Vp/Vs values, which could reflect short-term local concentrations of high pore pressures or other interactions of the treatment with the formation. The relationship between source parameters and variations in Vp/Vs are also examined. This technique has the potential to provide a unique and dynamic view of variations in the reservoir both spatially and temporally.

Mechanical properties of highly defective graphene: from brittle rupture to ductile fracture.

PubMed

Xu, Lanqing; Wei, Ning; Zheng, Yongping

2013-12-20

Defects are generally believed to deteriorate the superlative performance of graphene-based devices but may also be useful when carefully engineered to tailor the local properties and achieve new functionalities. Central to most defect-associated applications is the defect coverage and arrangement. In this work, we investigate, by molecular dynamics simulations, the mechanical properties and fracture dynamics of graphene sheets with randomly distributed vacancies or Stone-Wales defects under tensile deformations over a wide defect coverage range. With defects presented, an sp-sp(2) bonding network and an sp-sp(2)-sp(3) bonding network are observed in vacancy-defected and Stone-Wales-defected graphene, respectively. The ultimate strength degrades gradually with increasing defect coverage and saturates in the high-ratio regime, whereas the fracture strain presents an unusual descending-saturating-improving trend. In the dense vacancy defect situation, the fracture becomes more plastic and super-ductility is observed. Further fracture dynamics analysis reveals that the crack trapping by sp-sp(2) and sp-sp(2)-sp(3) rings and the crack-tip blunting account for the ductile fracture, whereas geometric rearrangement on the entire sheet for vacancy defects and geometric rearrangement on the specific defect sites for Stone-Wales defects account for their distinctive rules of the evolution of the fracture strain.

Stress fractures of the foot and ankle, part 2: site-specific etiology, imaging, and treatment, and differential diagnosis.

PubMed

Mandell, Jacob C; Khurana, Bharti; Smith, Stacy E

2017-09-01

Stress fractures of the foot and ankle are a commonly encountered problem among athletes and individuals participating in a wide range of activities. This illustrated review, the second of two parts, discusses site-specific etiological factors, imaging appearances, treatment options, and differential considerations of stress fractures of the foot and ankle. The imaging and clinical management of stress fractures of the foot and ankle are highly dependent on the specific location of the fracture, mechanical forces acting upon the injured site, vascular supply of the injured bone, and the proportion of trabecular to cortical bone at the site of injury. The most common stress fractures of the foot and ankle are low risk and include the posteromedial tibia, the calcaneus, and the second and third metatarsals. The distal fibula is a less common location, and stress fractures of the cuboid and cuneiforms are very rare, but are also considered low risk. In contrast, high-risk stress fractures are more prone to delayed union or nonunion and include the anterior tibial cortex, medial malleolus, navicular, base of the second metatarsal, proximal fifth metatarsal, hallux sesamoids, and the talus. Of these high-risk types, stress fractures of the anterior tibial cortex, the navicular, and the proximal tibial cortex may be predisposed to poor healing because of the watershed blood supply in these locations. The radiographic differential diagnosis of stress fracture includes osteoid osteoma, malignancy, and chronic osteomyelitis.

Changes in biochemical markers after lower limb fractures.

PubMed

Stoffel, Karl; Engler, Hanna; Kuster, Markus; Riesen, Walter

2007-01-01

The bone remodeling sequence after bone fracture changes the concentrations of biochemical bone markers, but the relationships of fracture size and of healing time to changes in biomarkers are unclear. The present pilot study was undertaken to determine the changes found in serum bone markers after plate osteosynthesis of closed distal tibial and malleolar fractures during a study period of 24 weeks. We measured tatrate-resistant acid phosphatase (TRACP 5b), collagen type I C-terminal telopeptide (ICTP), bone-specific alkaline phosphatase (bone ALP), osteocalcin (OC), procollagen type I C-terminal propeptide (PICP), procollagen type III N-terminal propeptide (PIIINP), and human cartilage glycoprotein 39 (YKL-40) in 20 patients with lower limb fractures (10 malleolar, 10 tibia). A physical examination and radiographs were completed to assess evidence of union. All malleolar fractures healed within 6 weeks, whereas 2 tibial fractures did not show complete bone healing after 24 weeks. Changes were comparable but more pronounced in the tibia group, and marker concentrations remained increased at the end of study (bone ALP, 86 vs 74 U/L; OC, 14.9 vs 7.7 microg/L; ICTP: 5.6 vs 3.3 microg/L at day 84 after osteosynthesis, P <0.05 in tibia; 80 vs 70 U/L, 8 vs 5.2 microg/L, and 3.5 vs 3.2 microg/L, respectively, in the malleolar fracture group). In normal bone healing, changes in bone turnover markers were primarily dependent on the fracture size. Delayed tibia fracture healing may involve a disturbance in bone remodeling.

Geophysical Properties of Hard Rock for Investigation of Stress Fields in Deep Mines

NASA Astrophysics Data System (ADS)

Tibbo, M.; Young, R. P.; Schmitt, D. R.; Milkereit, B.

2014-12-01

A complication in geophysical monitoring of deep mines is the high-stress dependency of the physical properties of hard rocks. In-mine observations show anisotropic variability of the in situ P- and S-wave velocities and resistivity of the hard rocks that are likely related to stress field changes. As part of a comprehensive study in a deep, highly stressed mine located in Sudbury, Ontario, Canada, data from in situ monitoring of the seismicity, conductivity, stress, and stress dependent physical properties has been obtain. In-laboratory experiments are also being performed on borehole cores from the Sudbury mines. These experiments will measure the Norite borehole core's properties including elastic modulus, bulk modulus, P- and S-wave velocities, and density. Hydraulic fracturing has been successfully implemented in industries such as oil and gas and enhanced geothermal systems, and is currently being investigated as a potential method for preconditioning in mining. However, further research is required to quantify how hydraulic fractures propagate through hard, unfractured rock as well as naturally fractured rock typically found in mines. These in laboratory experiments will contribute to a hydraulic fracturing project evaluating the feasibility and effectiveness of hydraulic fracturing as a method of de-stressing hard rock mines. A tri-axial deformation cell equipped with 18 Acoustic Emission (AE) sensors will be used to bring the borehole cores to a tri-axial state of stress. The cores will then be injected with fluid until the the hydraulic fracture has propagated to the edge of the core, while AE waveforms will be digitized continuously at 10 MHz and 12-bit resolution for the duration of each experiment. These laboratory hydraulic fracture experiments will contribute to understanding how parameters including stress ratio, fluid injection rate, and viscosity, affect the fracturing process.

Evaluation of fracture toughness and mechanical properties of ternary thiol-ene-methacrylate systems as resin matrix for dental restorative composites.

PubMed

Beigi, Saeed; Yeganeh, Hamid; Atai, Mohammad

2013-07-01

Study and evaluation of fracture toughness, flexural and dynamic mechanical properties, and crosslink density of ternary thiol-ene-methacrylate systems and comparison with corresponding conventional methacrylate system were considered in the present study. Urethane tetra allyl ether monomer (UTAE) was synthesized as ene monomer. Different formulations were prepared based on combination of UTAE, BisGMA/TEGDMA and a tetrathiol monomer (PETMP). The photocuring reaction was conducted under visible light using BD/CQ combination as photoinitiator system. Mechanical properties were evaluated via measuring flexural strength, flexural modulus and fracture toughness. Scanning electron microscopy (SEM) was utilized to study the morphology of the fractured specimen's cross section. Viscoelastic properties of the samples were also determined by dynamic mechanical thermal analysis (DMTA). The same study was performed on a conventional methacrylate system. The data were analyzed and compared by ANOVA and Tukey HSD tests (significance level=0.05). The results showed improvement in fracture toughness of the specimens containing thiol-ene moieties. DMTA revealed a lower glass transition temperature and more homogenous structure for thiol-ene containing specimens in comparison to the system containing merely methacrylate monomer. The flexural modulus and flexural strength of the specimens with higher thiol-ene content were lower than the neat methacrylate system. The SEM micrographs of the fractured surface of specimens with higher methacrylate content were smooth and mirror-like (shiny) which represent brittle fracture. The thiol-ene-methacrylate system can be used as resin matrix of dental composites with enhanced fracture toughness in comparison to the methacrylate analogous. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Triceps-sparing approach for open reduction and internal fixation of neglected displaced supracondylar and distal humeral fractures in children.

PubMed

Rizk, Ahmed Shawkat

2015-06-01

Supracondylar humeral fractures are one of the most common skeletal injuries in children. In cases of displacement and instability, the standard procedure is early closed reduction and percutaneous Kirschner wire fixation. However, between 10 and 20 % of patients present late. According to the literature, patients with neglected fractures are those patients who presented for treatment after 14 days of injury. The delay is either due to lack of medical facilities or social and financial constraints. The neglected cases are often closed injuries with no vascular compromise. However, the elbow may still be tense and swollen with abrasions or crusts. In neglected cases, especially after early appearance of callus, there is no place for closed reduction and percutaneous pinning. Traditionally, distal humeral fractures have been managed with surgical approaches that disrupt the extensor mechanism with less satisfactory functional outcome due to triceps weakness and elbow stiffness. The aim of this study is to evaluate the outcome of delayed open reduction using the triceps-sparing approach and Kirschner wire fixation for treatment of neglected, displaced supracondylar and distal humeral fractures in children. This prospective study included 15 children who had neglected displaced supracondylar and distal humeral fractures. All patients were completely evaluated clinically and radiologically before intervention, after surgery and during the follow-up. The follow-up period ranged from 8 to 49 months, with a mean period of 17 months. Functional outcome was evaluated according to the Mayo Elbow Performance Index (MEPI) and Mark functional criteria. All fractures united in a mean duration of 7.2 weeks (range 5-10 weeks) with no secondary displacement or mal-union. Excellent results were found at the last follow-up in 13 of the 15 patients studied (86.66 %), while good results were found in two patients (13.33 %) according to the MEPI scale. According to the Mark functional criteria, there was one patient with a fair result (6.66 %). The results were very satisfactory if compared with traditional operative techniques, with many advantages including anatomical reduction and fixation of the fractures, avoidance of ulnar nerve injury, preservation of the extensor mechanism, decrease in incidence of myositis ossificans around the elbow and decrease in post-operative stiffness. IV.

[Mechanical property of tooth-like yttria-stabilized tetragonal zirconia polycrystal by adding rare earth oxide].

PubMed

Gao, Yan; Zhang, Fuqiang; Gao, Jianhua

2012-02-01

To evaluate the influence of mechanical property of tooth-like yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) by adding rare earth oxide as colorants. Six kinds of tooth-like Y-TZP were made by introducing internal coloration technology. The colorants included rare earth oxide (Pr6O11, CeO2, Er2O3) and transition element oxide (MnO2). Mechanical properties (flexural strength, vickers hardness and fracture toughness) were tested. Microstructure was examined by scanning electron microscope(SEM), and the fracture model was analyzed. The range of flexural strength of the six kinds of tooth-like Y-TZP were (792 +/- 20)-(960 +/- 17) MPa, the fracture toughness were (4.72 +/- 0.31)-(5.64 +/- 0.38) MPam(1/2), and the vickers hardness were (1332 +/- 19)-(1380 +/- 17) MPa. SEM observation on the cross section of the six kinds of sintered composites showed a relatively dense polycrystal structure, and the fracture models was mixed type. Tooth-like Y-TZP is acquired with better mechanical properties (fracture toughness and vickers hardness) by adding rare earth oxide as colorants. It is available for clinical application.

Predicting the Macroscopic Fracture Energy of Epoxy Resins from Atomistic Molecular Simulations

DOE PAGES

Meng, Zhaoxu; Bessa, Miguel A.; Xia, Wenjie; ...

2016-12-06

Predicting the macroscopic fracture energy of highly crosslinked glassy polymers from atomistic simulations is challenging due to the size of the process zone being large in these systems. Here, we present a scale-bridging approach that links atomistic molecular dynamics simulations to macroscopic fracture properties on the basis of a continuum fracture mechanics model for two different epoxy materials. Our approach reveals that the fracture energy of epoxy resins strongly depends on the functionality of epoxy resin and the component ratio between the curing agent (amine) and epoxide. The most intriguing part of our study is that we demonstrate that themore » fracture energy exhibits a maximum value within the range of conversion degrees considered (from 65% to 95%), which can be attributed to the combined effects of structural rigidity and post-yield deformability. Our study provides physical insight into the molecular mechanisms that govern the fracture characteristics of epoxy resins and demonstrates the success of utilizing atomistic molecular simulations towards predicting macroscopic material properties.« less

Predicting the Macroscopic Fracture Energy of Epoxy Resins from Atomistic Molecular Simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meng, Zhaoxu; Bessa, Miguel A.; Xia, Wenjie

Predicting the macroscopic fracture energy of highly crosslinked glassy polymers from atomistic simulations is challenging due to the size of the process zone being large in these systems. Here, we present a scale-bridging approach that links atomistic molecular dynamics simulations to macroscopic fracture properties on the basis of a continuum fracture mechanics model for two different epoxy materials. Our approach reveals that the fracture energy of epoxy resins strongly depends on the functionality of epoxy resin and the component ratio between the curing agent (amine) and epoxide. The most intriguing part of our study is that we demonstrate that themore » fracture energy exhibits a maximum value within the range of conversion degrees considered (from 65% to 95%), which can be attributed to the combined effects of structural rigidity and post-yield deformability. Our study provides physical insight into the molecular mechanisms that govern the fracture characteristics of epoxy resins and demonstrates the success of utilizing atomistic molecular simulations towards predicting macroscopic material properties.« less

Bone scan as a screening test for missed fractures in severely injured patients.

PubMed

Lee, K-J; Jung, K; Kim, J; Kwon, J

2014-12-01

In many cases, patients with severe blunt trauma have multiple fractures throughout the body. These fractures are not often detectable by history or physical examination, and their diagnosis can be delayed or even missed. Thus, screening test fractures of the whole body is required after initial management. We performed this study to evaluate the reliability of bone scans for detecting missed fractures in patients with multiple severe traumas and we analyzed the causes of missed fractures by using bone scan. A bone scan is useful as a screening test for fractures of the entire body of severe trauma patients who are passed the acute phase. We reviewed the electronic medical records of severe trauma patients who underwent a bone scan from September 2009 to December 2010. Demographic and medical data were compared and statistically analyzed to determine whether missed fractures were detected after bone scan in the two groups. A total of 382 patients who had an injury severity score [ISS] greater than 16 points with multiple traumas visited the emergency room. One hundred and thirty-one patients underwent bone scan and 81 patients were identified with missed fractures by bone scan. The most frequent location for missed fractures was the rib area (55 cases, 41.98%), followed by the extremities (42 cases, 32.06%). The missed fractures that required surgery or splint were most common in extremities (11 cases). In univariate analysis, higher ISS scores and mechanism of injury were related with the probability that missed fractures would be found with a bone scan. The ISS score was statistically significant in multivariate analysis. Bone scan is an effective method of detecting missed fractures among patients with multiple severe traumas. Level IV, retrospective study. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Effect of sintering process on the magnetic and mechanical properties of sintered Nd-Fe-B magnets

NASA Astrophysics Data System (ADS)

Hu, Z. H.; Qu, H. J.; Zhao, J. Q.; Yan, C. J.; Liu, X. M.

2014-11-01

The magnetic and mechanical properties of sintered Nd-Fe-B magnets prepared by different sintering processes were investigated. The results showed that the intrinsic coercivity and fracture toughness of sintered Nd-Fe-B magnets first increased, and then declined with increasing annealing temperature. The optimum magnetic properties and fracture toughness of sintered Nd-Fe-B magnets were obtained at the annealing temperature of 540 °C. Sintering temperature increasing from 1047 °C to 1071 °C had hardly effect on the magnetic properties of sintered Nd-Fe-B magnets. The variation of Vickers hardness and fracture toughness was not the same with increasing sintering temperature, and the effect of sintering temperature on the mechanical properties was complex and irregular. The reasons for the variation on magnetic and mechanical properties were analyzed, and we presumed that the effect of microstructure on the mechanical properties was more sensitive than the magnetic properties through analyzing the microstructure of sintered Nd-Fe-B magnets.

Mathematical modeling and simulation analysis of hydraulic fracture propagation in three-layered poro-elastic media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moon, H.Y.; Advani, S.H.; Lee, T.S.

1992-11-01

Hydraulic fracturing plays a pivotal role in the enhancement of oil and gas production recovery from low permeability reservoirs. The process of hydraulic fracturing entails the generation of a fracture by pumping fluids blended with special chemicals and proppants into the payzone at high injection rates and pressures to extend and wedge fractures. The mathematical modeling of hydraulically induced fractures generally incorporates coupling between the formation elasticity, fracture fluid flow, and fracture mechanics equations governing the formation structural responses, fluid pressure profile, and fracture growth. Two allied unsymmetric elliptic fracture models are developed for fracture configuration evolutions in three-layered rockmore » formations. The first approach is based on a Lagrangian formulation incorporating pertinent energy components associated with the formation structural responses and fracture fluid flow. The second model is based on a generalized variational principle, introducing an energy rate related functional. These models initially simulate a penny-shaped fracture, which becomes elliptic if the crack tips encounters (upper and/or lower) barriers with differential reservoir properties (in situ stresses, 16 elastic moduli, and fracture toughness-contrasts and fluid leak-off characteristics). The energy rate component magnitudes are determined to interpret the governing hydraulic fracture mechanisms during fracture evolution. The variational principle is extended to study the phenomenon and consequences of fluid lag in fractures. Finally, parametric sensitivity and energy rate investigations to evaluate the roles of controllable hydraulic treatment variables and uncontrollable reservoir property characterization parameters are performed. The presented field applications demonstrate the overall capabilities of the developed models. These studies provide stimulation treatment guidelines for fracture configuration design, control, and optimization.« less

Application of characteristic time concepts for hydraulic fracture configuration design, control, and optimization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Advani, S.H.; Lee, T.S.; Moon, H.

1992-10-01

The analysis of pertinent energy components or affiliated characteristic times for hydraulic stimulation processes serves as an effective tool for fracture configuration designs optimization, and control. This evaluation, in conjunction with parametric sensitivity studies, provides a rational base for quantifying dominant process mechanisms and the roles of specified reservoir properties relative to controllable hydraulic fracture variables for a wide spectrum of treatment scenarios. Results are detailed for the following multi-task effort: (a) Application of characteristic time concept and parametric sensitivity studies for specialized fracture geometries (rectangular, penny-shaped, elliptical) and three-layered elliptic crack models (in situ stress, elastic moduli, and fracturemore » toughness contrasts). (b) Incorporation of leak-off effects for models investigated in (a). (c) Simulation of generalized hydraulic fracture models and investigation of the role of controllable vaxiables and uncontrollable system properties. (d) Development of guidelines for hydraulic fracture design and optimization.« less

Application of characteristic time concepts for hydraulic fracture configuration design, control, and optimization. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Advani, S.H.; Lee, T.S.; Moon, H.

1992-10-01

The analysis of pertinent energy components or affiliated characteristic times for hydraulic stimulation processes serves as an effective tool for fracture configuration designs optimization, and control. This evaluation, in conjunction with parametric sensitivity studies, provides a rational base for quantifying dominant process mechanisms and the roles of specified reservoir properties relative to controllable hydraulic fracture variables for a wide spectrum of treatment scenarios. Results are detailed for the following multi-task effort: (a) Application of characteristic time concept and parametric sensitivity studies for specialized fracture geometries (rectangular, penny-shaped, elliptical) and three-layered elliptic crack models (in situ stress, elastic moduli, and fracturemore » toughness contrasts). (b) Incorporation of leak-off effects for models investigated in (a). (c) Simulation of generalized hydraulic fracture models and investigation of the role of controllable vaxiables and uncontrollable system properties. (d) Development of guidelines for hydraulic fracture design and optimization.« less

Controlled shear/tension fixture

DOEpatents

Hsueh, Chun-Hway [Knoxville, TN; Liu, Chain-tsuan [Knoxville, TN; George, Easo P [Knoxville, TN

2012-07-24

A test fixture for simultaneously testing two material test samples is provided. The fixture provides substantially equal shear and tensile stresses in each test specimens. By gradually applying a load force to the fixture only one of the two specimens fractures. Upon fracture of the one specimen, the fixture and the load train lose contact and the second specimen is preserved in a state of upset just prior to fracture. Particular advantages of the fixture are (1) to control the tensile to shear load on the specimen for understanding the effect of these stresses on the deformation behavior of advanced materials, (2) to control the location of fracture for accessing localized material properties including the variation of the mechanical properties and residual stresses across the thickness of advanced materials, (3) to yield a fractured specimen for strength measurement and an unfractured specimen for examining the microstructure just prior to fracture.

Dynamic Mechanical Properties and Fracture Surface Morphologies of Core-Shell Rubber (CSR) Toughened Epoxy at Liquid Nitrogen (Ln2) Temperatures

NASA Technical Reports Server (NTRS)

Wang, J.; Magee, D.; Schneider, J. A.

2009-01-01

The dynamic mechanical properties and fracture surface morphologies were evaluated for a commercial epoxy resin toughened with two types of core-shell rubber (CSR) toughening agents (Kane Ace(Registered TradeMark) MX130 and MX960). The impact resistance (R) was evaluated by the resulting breaking energy measured in Charpy impact tests conducted on an instrumented drop tower. The resulting fracture surface morphologies were examined using Scanning Electron Microscopy (SEM). Fractographic observations of the CSR toughened epoxy tested at ambient temperature, showed a fracture as characterized by slender dendrite textures with large voids. The increasing number of dendrites and decreasing size of scale-like texture with more CSR particles corresponded with increased R. As the temperature decreased to Liquid Nitrogen (LN 2), the fracture surfaces showed a fracture characterized by a rough, torn texture containing many river markings and deep furrows.

Effect of water on critical and subcritical fracture properties of Woodford shale

NASA Astrophysics Data System (ADS)

Chen, Xiaofeng; Eichhubl, Peter; Olson, Jon E.

2017-04-01

Subcritical fracture behavior of shales under aqueous conditions is poorly characterized despite increased relevance to oil and gas resource development and seal integrity in waste disposal and subsurface carbon sequestration. We measured subcritical fracture properties of Woodford shale in ambient air, dry CO2 gas, and deionized water by using the double-torsion method. Compared to tests in ambient air, the presence of water reduces fracture toughness by 50%, subcritical index by 77%, and shear modulus by 27% and increases inelastic deformation. Comparison between test specimens coated with a hydrophobic agent and uncoated specimens demonstrates that the interaction of water with the bulk rock results in the reduction of fracture toughness and enhanced plastic effects, while water-rock interaction limited to the vicinity of the propagating fracture tip by a hydrophobic specimen coating lowers subcritical index and increases fracture velocity. The observed deviation of a rate-dependent subcritical index from the power law K-V relations for coated specimens tested in water is attributed to a time-dependent weakening process resulting from the interaction between water and clays in the vicinity of the fracture tip.

Monitoring the mechanical properties of healing bone.

PubMed

Claes, L E; Cunningham, J L

2009-08-01

Fracture healing is normally assessed through an interpretation of radiographs, clinical evaluation, including pain on weight bearing, and a manual assessment of the mobility of the fracture. These assessments are subjective and their accuracy in determining when a fracture has healed has been questioned. Viewed in mechanical terms, fracture healing represents a steady increase in strength and stiffness of a broken bone and it is only when these values are sufficiently high to support unrestricted weight bearing that a fracture can be said to be healed. Information on the rate of increase of the mechanical properties of a healing bone is therefore valuable in determining both the rate at which a fracture will heal and in helping to define an objective and measurable endpoint of healing. A number of techniques have been developed to quantify bone healing in mechanical terms and these are described and discussed in detail. Clinical studies, in which measurements of fracture stiffness have been used to identify a quantifiable end point of healing, compare different treatment methods, predictably determine whether a fracture will heal, and identify factors which most influence healing, are reviewed and discussed.

Concurrent dorsal dislocations and fracture-dislocations of the index, long, ring, and small (second to fifth) carpometacarpal joints.

PubMed

Prokuski, L J; Eglseder, W A

2001-11-01

To review the outcome of patients with concurrent dorsal dislocations and fracture-dislocations of the second, third, fourth, and fifth carpometacarpal (CMC) joints treated with open reduction and internal fixation (ORIF). Retrospective review. Level 1 trauma center. Between 1991 and 1997, twelve multiply injured patients with the described CMC injury complex (one open injury) were treated with ORIF (eleven patients) or percutaneous wire fixation (one patient) by the same surgeon. Treatment consisted of ORIF with Kirschner wires followed by splints and immediate metacarpophalangeal and interphalangeal joint range of motion exercises. Grip strength, wrist and finger range of motion, pain, need for additional surgery, and return to work. Of the ten patients available for follow-up (mean, three years), all had been treated with ORIF (eight within forty-eight hours of injury and two had treatment delayed for four weeks because of delayed diagnosis and management of more serious injuries). Three patients had additional surgery (planned secondary second and third CMC arthrodeses). Grip strength of the operated hand in the five patients with JAMAR testing was 50 percent (n = 3), 75 percent (n = 1), and 90 percent (n = 1) of that in their contralateral hands. Five patients were pain-free, and five reported occasional, activity-related pain. The five patients who worked before the injury returned to their previous occupations (one with slightly modified duties). This is the largest series of patients with this CMC injury complex and the first report of open CMC dorsal dislocations and fracture-dislocations. Although early ORIF is suggested, delay of up to four weeks did not adversely affect results.

Inferring field-scale properties of a fractured aquifer from ground surface deformation during a well test

NASA Astrophysics Data System (ADS)

Schuite, Jonathan; Longuevergne, Laurent; Bour, Olivier; Boudin, Frédérick; Durand, Stéphane; Lavenant, Nicolas

2015-12-01

Fractured aquifers which bear valuable water resources are often difficult to characterize with classical hydrogeological tools due to their intrinsic heterogeneities. Here we implement ground surface deformation tools (tiltmetry and optical leveling) to monitor groundwater pressure changes induced by a classical hydraulic test at the Ploemeur observatory. By jointly analyzing complementary time constraining data (tilt) and spatially constraining data (vertical displacement), our results strongly suggest that the use of these surface deformation observations allows for estimating storativity and structural properties (dip, root depth, and lateral extension) of a large hydraulically active fracture, in good agreement with previous studies. Hence, we demonstrate that ground surface deformation is a useful addition to traditional hydrogeological techniques and opens possibilities for characterizing important large-scale properties of fractured aquifers with short-term well tests as a controlled forcing.

Hyperkyphosis, Kyphosis Progression, and Risk of Non-Spine Fractures in Older Community Dwelling Women: The Study of Osteoporotic Fractures (SOF)

PubMed Central

Kado, Deborah M.; Miller-Martinez, Dana; Lui, Li-Yung; Cawthon, Peggy; Katzman, Wendy B.; Hillier, Teresa A.; Fink, Howard A.; Ensrud, Kristine E.

2014-01-01

While accentuated kyphosis is associated with osteoporosis, it is unknown whether it increases risk of future fractures, independent of bone mineral density (BMD) and vertebral fractures. We examined the associations of baseline Cobb angle kyphosis and 15 year change in kyphosis with incident non-spine fractures using data from the Study of Osteoporotic Fractures. A total of 994 predominantly white women, aged 65 or older, were randomly sampled from 9,704 original participants to have repeated Cobb angle measurements of kyphosis measured from lateral spine radiographs at baseline and an average of 15 years later. Non-spine fractures, confirmed by radiographic report, were assessed every four months for up to 21.3 years. Compared with women in the lower three quartiles of kyphosis, women with kyphosis greater than 53 degrees (top quartile) had a 50% increased risk of non-spine fracture (95% CI, 1.10 –2.06 after adjusting for BMD, prevalent vertebral fractures, prior history of fractures, and other fracture risk factors. Cobb angle kyphosis progressed an average of 7 degrees (SD = 6.8) over 15 years. Per 1 SD increase in kyphosis change, there was a multivariable adjusted 28% increased risk of fracture (95% CI, 1.06 – 1.55) that was attenuated by further adjustment for baseline BMD (HR per SD increase in kyphosis change, 1.19; 95% CI 0.99 –1.44). Greater kyphosis is associated with an elevated non-spine fracture risk independent of traditional fracture risk factors in older women. Furthermore, worsening kyphosis is also associated with increased fracture risk that is partially mediated by low baseline BMD that itself is a risk factor for kyphosis progression. These results suggest that randomized controlled fracture intervention trials should consider implementing kyphosis measures to: 1) further study kyphosis and kyphosis change as an additional fracture risk factor; and 2) test whether therapies may improve or delay its progression. PMID:24715607

Hyperkyphosis, kyphosis progression, and risk of non-spine fractures in older community dwelling women: the study of osteoporotic fractures (SOF).

PubMed

Kado, Deborah M; Miller-Martinez, Dana; Lui, Li-Yung; Cawthon, Peggy; Katzman, Wendy B; Hillier, Teresa A; Fink, Howard A; Ensrud, Kristine E

2014-10-01

While accentuated kyphosis is associated with osteoporosis, it is unknown whether it increases risk of future fractures, independent of bone mineral density (BMD) and vertebral fractures. We examined the associations of baseline Cobb angle kyphosis and 15 year change in kyphosis with incident non-spine fractures using data from the Study of Osteoporotic Fractures. A total of 994 predominantly white women, aged 65 or older, were randomly sampled from 9704 original participants to have repeated Cobb angle measurements of kyphosis measured from lateral spine radiographs at baseline and an average of 15 years later. Non-spine fractures, confirmed by radiographic report, were assessed every 4 months for up to 21.3 years. Compared with women in the lower three quartiles of kyphosis, women with kyphosis greater than 53° (top quartile) had a 50% increased risk of non-spine fracture (95% CI, 1.10-2.06 after adjusting for BMD, prevalent vertebral fractures, prior history of fractures, and other fracture risk factors. Cobb angle kyphosis progressed an average of 7° (SD = 6.8) over 15 years. Per 1 SD increase in kyphosis change, there was a multivariable adjusted 28% increased risk of fracture (95% CI, 1.06-1.55) that was attenuated by further adjustment for baseline BMD (HR per SD increase in kyphosis change, 1.19; 95% CI 0.99-1.44). Greater kyphosis is associated with an elevated non-spine fracture risk independent of traditional fracture risk factors in older women. Furthermore, worsening kyphosis is also associated with increased fracture risk that is partially mediated by low baseline BMD that itself is a risk factor for kyphosis progression. These results suggest that randomized controlled fracture intervention trials should consider implementing kyphosis measures to the following: (1) further study kyphosis and kyphosis change as an additional fracture risk factor; and (2) test whether therapies may improve or delay its progression. © 2014 American Society for Bone and Mineral Research.

Minimally invasive plating osteosynthesis for mid-distal third humeral shaft fractures.

PubMed

Lian, Kejian; Wang, Lei; Lin, Dasheng; Chen, Zhiwen

2013-08-01

Mid-distal third humeral shaft fractures can be effectively treated with minimally invasive plating osteosynthesis and intramedullary nailing (IMN). However, these 2 treatments have not been adequately compared. Forty-seven patients (47 fractures) with mid-distal third humeral shaft fractures were randomly allocated to undergo either minimally invasive plating osteosynthesis (n=24) or IMN (n=23). The 2 groups were similar in terms of fracture patterns, fracture location, age, and associated injuries. Intraoperative measurements included blood loss and operative time. Clinical outcome measurements included fracture healing, radial nerve recovery, and elbow and shoulder discomfort. Radiographic measurements included fracture alignment, time to healing, delayed union, and nonunion. Functional outcome was satisfactory in both groups. Mean American Shoulder and Elbow Surgeons score and Mayo score were both better for the minimally invasive plating osteosynthesis group than for the IMN group (98.2 vs 97.6, respectively, and 93.5 vs 94.1, respectively; P<.001). Operative time was shorter and less intraoperative blood loss occurred in the minimally invasive plating osteosynthesis group than in the IMN group. Average time to union was similar in both groups. Primary union was achieved in 23 of 24 patients in the minimally invasive plating osteosynthesis group and in 22 of 23 in the IMN group. Minimally invasive plating osteosynthesis may have outcomes comparable with IMN for the management of mid-distal third humeral shaft fractures. Minimally invasive plating osteosynthesis is more suitable for complex fractures, especially for radial protection and motion recovery of adjacent joints, compared with IMN for simple fractures. Copyright 2013, SLACK Incorporated.

Zoledronic Acid for the Treatment and Prevention of Primary and Secondary Osteoporosis

PubMed Central

Rizzoli, René

2010-01-01

There is increasing interest in therapies that can be administered less frequently and/or avoid gastrointestinal irritation. The efficacy of once-yearly zoledronic acid (5 mg) in the treatment and prevention of osteoporosis has been evaluated in different patient populations. In the 3-year HORIZON-Pivotal Fracture Trial in postmenopausal women with osteoporosis, zoledronic acid reduced the risk of vertebral and hip fracture by 70% and 41%, respectively, versus placebo. The efficacy of zoledronic acid in preventing subsequent fracture in patients with a hip fracture was evaluated in the HORIZON-Recurrent Fracture Trial. New vertebral and nonvertebral fractures were significantly reduced by treatment initiated within 90 days of incident hip fracture, without evidence of delayed fracture healing. Data from a 1-year study show that a single zoledronic acid 5-mg infusion is superior to oral risedronate 5 mg/day for treatment and prevention of glucocorticoid-induced osteoporosis. Increases in bone mineral density and decreases in bone turnover markers were significantly greater with zoledronic acid than with risedronate. Two different treatment regimens of zoledronic acid were found to be more effective than placebo for prevention of bone loss in postmenopausal women and reducing markers of bone turnover after 2 years. In conclusion, zoledronic acid 5 mg once-yearly infusion has demonstrated marked efficacy in the treatment and prevention of primary and secondary osteoporosis, with a combination of fracture risk reduction and prevention of bone loss at key sites. It is the only agent shown to reduce the incidence of fracture and mortality in patients with a previous low-trauma hip fracture. PMID:22870433

Shale Gas Well, Hydraulic Fracturing, and Formation Data to Support Modeling of Gas and Water Flow in Shale Formations

NASA Astrophysics Data System (ADS)

Edwards, Ryan W. J.; Celia, Michael A.

2018-04-01

The potential for shale gas development and hydraulic fracturing to cause subsurface water contamination has prompted a number of modeling studies to assess the risk. A significant impediment for conducting robust modeling is the lack of comprehensive publicly available information and data about the properties of shale formations, shale wells, the process of hydraulic fracturing, and properties of the hydraulic fractures. We have collated a substantial amount of these data that are relevant for modeling multiphase flow of water and gas in shale gas formations. We summarize these data and their sources in tabulated form.

Laboratory investigations into fracture propagation characteristics of rock material

NASA Astrophysics Data System (ADS)

Prasad, B. N. V. Siva; Murthy, V. M. S. R.

2018-04-01

After Industrial Revolution, demand of materials for building up structures have increased enormously. Unfortunately, failures of such structures resulted in loss of life and property. Rock is anisotropic and discontinuous in nature with inherent flaws or so-called discontinuities in it. Rock is apparently used for construction in mining, civil, tunnelling, hydropower, geothermal and nuclear sectors [1]. Therefore, the strength of the structure built up considering rockmass as the construction material needs proper technical evaluation during designing stage itself to prevent and predict the scenarios of catastrophic failures due to these inherent fractures [2]. In this study, samples collected from nine different drilling sites have been investigated in laboratory for understanding the fracture propagation characteristics in rock. Rock material properties, ultrasonic velocities through pulse transmission technique and Mode I Fracture Toughness Testing of different variants of Dolomites and Graywackes are determined in laboratory and the resistance of the rock material to catastrophic crack extension or propagation has been determined. Based on the Fracture Toughness values and the rock properties, critical Energy Release Rates have been estimated. However further studies in this direction is to be carried out to understand the fracture propagation characteristics in three-dimensional space.

A new approach to tracer transport analysis: From fracture systems to strongly heterogeneous porous media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsang, Chin-Fu

Many current development and utilization of groundwater resources include a study of their flow and transport properties. These properties are needed in evaluating possible changes in groundwater quality and potential transport of hazardous solutes through the groundwater system. Investigation of transport properties of fractured rocks is an active area of research. Most of the current approaches to the study of flow and transport in fractured rocks cannot be easily used for analysis of tracer transport field data. A new approach is proposed based on a detailed study of transport through a fracture of variable aperture. This is a two-dimensional stronglymore » heterogeneous permeable system. It is suggested that tracer breakthrough curves can be analyzed based on an aperture or permeability probability distribution function that characterizes the tracer flow through the fracture. The results are extended to a multi-fracture system and can be equally applied to a strongly heterogeneous porous medium. Finally, the need for multi-point or line and areal tracer injection and observation tests is indicated as a way to avoid the sensitive dependence of point measurements on local permeability variability. 30 refs., 15 figs.« less

Scanning electron microscope fractography in failure analysis of steels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wouters, R.; Froyen, L.

1996-04-01

For many failure cases, macroscopic examination of the fracture surface permits discrimination of fatigue fractures from overload fractures. For clarifying fatigue fractures, the practical significance of microfractography is limited to an investigation of the crack initiation areas. Scanning electron microscopy is successfully used in tracing local material abnormalities that act as fatigue crack initiators. The task for the scanning electron microscope, however, is much more substantial in failure analysis of overload fractures, especially for steels. By revealing specific fractographic characteristics, complemented by information about the material and the loading conditions, scanning electron microscopy provides a strong indication of the probablemore » cause of failure. A complete dimple fracture is indicative of acceptable bulk material properties; overloading, by subdimensioning or excessive external loading, has to be verified. The presence of cleavage fracture makes the material properties questionable if external conditions causing embrittlement are absent. Intergranular brittle fracture requires verification of grain-boundary weakening conditions--a sensitized structure, whether or not combined with a local stress state or a specific environment. The role of scanning electron microscopy in failure analysis is illustrated by case histories of the aforementioned fracture types.« less

Factors related to mortality after osteoporotic hip fracture treatment at Chiang Mai University Hospital, Thailand, during 2006 and 2007.

PubMed

Chaysri, Rathasart; Leerapun, Taninnit; Klunklin, Kasisin; Chiewchantanakit, Siripong; Luevitoonvechkij, Sirichai; Rojanasthien, Sattaya

2015-01-01

To investigate the one-year mortality rate after osteoporotic hip fracture and to identify factors associated with that mortality rate. A retrospective review of 275 osteoporotic patients who sustained a low-trauma hip fracture and were admitted in Chiang Mai University Hospital during January 1, 2006 to December 31, 2007 was accomplished. Eligibility criteria were defined as age over 50 years, fracture caused by a simple fall and not apathologicalfracture caused by cancer or infection. Results of this one-year mortality rate study were compared to studies of hip fracture patient mortality in 1997 and the period 1998-2003. The average one-year mortality rate in 2006-2007 was 21.1%. Factors correlated with higher mortality were non-operative treatment, delayed surgical treatment, and absence of medical treatment for osteoporosis. The 2006-2007 mortality rate was slightly higher than for the 1997 and 1998-2003 periods. The one-year mortality rate after osteoporotic hip fracture of 21.1% was approximately 9.3 times the mortality rate for the same age group in the general population, indicating that treatment of osteoporosis as a means of helping prevent hip fracture is very important for the individual, the family, and society as a whole.

Rib fractures and death from deletion of osteoblast βcatenin in adult mice is rescued by corticosteroids.

PubMed

Duan, JinZhu; Lee, Yueh; Jania, Corey; Gong, Jucheng; Rojas, Mauricio; Burk, Laurel; Willis, Monte; Homeister, Jonathon; Tilley, Stephen; Rubin, Janet; Deb, Arjun

2013-01-01

Ribs are primarily made of cortical bone and are necessary for chest expansion and ventilation. Rib fractures represent the most common type of non-traumatic fractures in the elderly yet few studies have focused on the biology of rib fragility. Here, we show that deletion of βcatenin in Col1a2 expressing osteoblasts of adult mice leads to aggressive osteoclastogenesis with increased serum levels of the osteoclastogenic cytokine RANKL, extensive rib resorption, multiple spontaneous rib fractures and chest wall deformities. Within days of osteoblast specific βcatenin deletion, animals die from respiratory failure with a vanishing rib cage that is unable to sustain ventilation. Increased bone resorption is also observed in the vertebrae and femur. Treatment with the bisphosphonate pamidronate delayed but did not prevent death or associated rib fractures. In contrast, administration of the glucocorticoid dexamethasone decreased serum RANKL and slowed osteoclastogenesis. Dexamethasone preserved rib structure, prevented respiratory compromise and strikingly increased survival. Our findings provide a novel model of accelerated osteoclastogenesis, where deletion of osteoblast βcatenin in adults leads to rapid development of destructive rib fractures. We demonstrate the role of βcatenin dependent mechanisms in rib fractures and suggest that glucocorticoids, by suppressing RANKL, may have a role in treating bone loss due to aggressive osteoclastogenesis.

Rib Fractures and Death from Deletion of Osteoblast βcatenin in Adult Mice Is Rescued by Corticosteroids

PubMed Central

Duan, JinZhu; Lee, Yueh; Jania, Corey; Gong, Jucheng; Rojas, Mauricio; Burk, Laurel; Willis, Monte; Homeister, Jonathon; Tilley, Stephen; Rubin, Janet; Deb, Arjun

2013-01-01

Ribs are primarily made of cortical bone and are necessary for chest expansion and ventilation. Rib fractures represent the most common type of non-traumatic fractures in the elderly yet few studies have focused on the biology of rib fragility. Here, we show that deletion of βcatenin in Col1a2 expressing osteoblasts of adult mice leads to aggressive osteoclastogenesis with increased serum levels of the osteoclastogenic cytokine RANKL, extensive rib resorption, multiple spontaneous rib fractures and chest wall deformities. Within days of osteoblast specific βcatenin deletion, animals die from respiratory failure with a vanishing rib cage that is unable to sustain ventilation. Increased bone resorption is also observed in the vertebrae and femur. Treatment with the bisphosphonate pamidronate delayed but did not prevent death or associated rib fractures. In contrast, administration of the glucocorticoid dexamethasone decreased serum RANKL and slowed osteoclastogenesis. Dexamethasone preserved rib structure, prevented respiratory compromise and strikingly increased survival. Our findings provide a novel model of accelerated osteoclastogenesis, where deletion of osteoblast βcatenin in adults leads to rapid development of destructive rib fractures. We demonstrate the role of βcatenin dependent mechanisms in rib fractures and suggest that glucocorticoids, by suppressing RANKL, may have a role in treating bone loss due to aggressive osteoclastogenesis. PMID:23393600

A Pronounced Inflammatory Activity Characterizes the Early Fracture Healing Phase in Immunologically Restricted Patients

PubMed Central

Hoff, Paula; Gaber, Timo; Strehl, Cindy; Jakstadt, Manuela; Hoff, Holger; Schmidt-Bleek, Katharina; Lang, Annemarie; Röhner, Eric; Huscher, Dörte; Matziolis, Georg; Burmester, Gerd-Rüdiger; Schmidmaier, Gerhard; Perka, Carsten; Duda, Georg N.; Buttgereit, Frank

2017-01-01

Immunologically restricted patients such as those with autoimmune diseases or malignancies often suffer from delayed or insufficient fracture healing. In human fracture hematomas and the surrounding bone marrow obtained from immunologically restricted patients, we analyzed the initial inflammatory phase on cellular and humoral level via flow cytometry and multiplex suspension array. Compared with controls, we demonstrated higher numbers of immune cells like monocytes/macrophages, natural killer T (NKT) cells, and activated T helper cells within the fracture hematomas and/or the surrounding bone marrow. Also, several pro-inflammatory cytokines such as Interleukin (IL)-6 and Tumor necrosis factor α (TNFα), chemokines (e.g., Eotaxin and RANTES), pro-angiogenic factors (e.g., IL-8 and Macrophage migration inhibitory factor: MIF), and regulatory cytokines (e.g., IL-10) were found at higher levels within the fracture hematomas and/or the surrounding bone marrow of immunologically restricted patients when compared to controls. We conclude here that the inflammatory activity on cellular and humoral levels at fracture sites of immunologically restricted patients considerably exceeds that of control patients. The initial inflammatory phase profoundly differs between these patient groups and is probably one of the reasons for prolonged or insufficient fracture healing often occurring within immunologically restricted patients. PMID:28282868

Assessment of carbon fibre composite fracture fixation plate using finite element analysis.

PubMed

Saidpour, Seyed H

2006-07-01

In the internal fixation of fractured bone by means of bone-plates fastened to the bone on its tensile surface, an on-going concern has been the excessive stress shielding of the bone by the excessively-stiff stainless-steel plate. The compressive stress shielding at the fracture-interface immediately after fracture-fixation delays callus formation and bone healing. Likewise, the tensile stress shielding in the layer of bone underneath the plate can cause osteoporosis and decrease in tensile strength of this layer. In this study a novel forearm internal fracture fixation plate made from short carbon fibre reinforced plastic (CFRP) was used in an attempt to address the problem. Accordingly, it has been possible to analyse the stress distribution in the composite plates using finite-element modelling. A three-dimensional, quarter-symmetric finite element model was generated for the plate system. The stress state in the underlying bone was examined for several loading conditions. Based on the analytical results the composite plate system is likely to reduce stress-shielding effects at the fracture site when subjected to bending and torsional loads. The design of the plate was further optimised by reducing the width around the innermost holes.

Intra-articular injuries of the elbow: pitfalls of diagnosis and treatment.

PubMed Central

Fowles, J. V.; Rizkallah, R.

1976-01-01

Poor results in treating fractures and dislocations about the elbow may be avoided if the surgeon is aware of the possible injuries, examines good radiographs of both elbows, and treats the injury promptly and appropriately. A displaced fracture of the lateral or medial condyle of the humerus should be suspected if there is a flake fracture of the adjoining metaphysis; open reduction and internal fixation give better results than closed reduction. A shear fracture of the capitulum humeri can only be seen on a lateral radiograph; excision of the fragment, followed by mobilization, is sufficient for a good functional result. Dislocation of the elbow in a child may avulse the medial epicondyle, which sometimes lodges in the joint; it is essential to recognize this and remove the fragment without delay to avoid early degenerative arthritis. An apparently isolated fracture of the ulna should alert the surgeon to the possibility of a dislocation of the radial head; the dislocation and the fracture must be reduced and stabilized to conserve elbow function. Images FIG. 1 FIG. 2 FIG. 3 FIG. 4 FIG. 5 FIG. 6 FIG. 7 FIG. 8 PMID:943224

Lag screw fixation of anterior mandibular fractures: a retrospective analysis of intraoperative and postoperative complications.

PubMed

Tiwana, Paul S; Kushner, George M; Alpert, Brian

2007-06-01

To review, retrospectively, the outcomes of 102 patients who underwent lag screw technique fixation of fractures of the anterior mandible. A total of 102 consecutive, skeletally mature patients who have undergone open reduction internal fixation for fractures of the anterior mandible utilizing the lag screw technique were reviewed. All patients had a clinically mobile fracture between the mental foramina of the mandible. The patients were followed at usual postoperative intervals with shortest long-term follow-up of 2 months. Intraoperative and long-term postoperative outcomes including status of union, infection, and intraoperative surgical misadventure were recorded. Data from the 102 patients showed that there was 1 fixation failure due to inappropriate patient selection, 1 nonunion requiring bone grafting, 1 with infected screws but with union, 1 with an infected screw and delayed union treated conservatively, and 6 with broken drills from intraoperative surgical misadventures. Lag screw osteosynthesis of anterior mandibular fractures is a sensitive, facile, predictable, and relatively inexpensive method for internal fixation of indicated fractures. As with all methods of rigid internal fixation, most failures or complications are the result of operator judgment or technique.

Use of Resorbable Fixation System in Pediatric Facial Fractures.

PubMed

Wong, Frankie K; Adams, Saleigh; Hudson, Donald A; Ozaki, Wayne

2017-05-01

Resorbable fixation system (RFS) is an alternative to titanium in open reduction and internal fixation of pediatric facial fractures. This study retrospectively reviewed all medical records in a major metropolitan pediatric hospital in Cape Town, South Africa from September 2010 through May 2014. Inclusion criteria were children under the age of 13 with facial fractures who have undergone open reduction and internal fixation using RFS. Intraoperative and postoperative complications were reviewed. A total of 21 patients were included in this study. Twelve were males and 9 were females. Good dental occlusion was achieved in all patients and there were no complications intraoperatively. Three patients developed postoperative implanted-related complications: all 3 patients developed malocclusions and 1 developed an additional sterile abscess over the right zygomatic bone. For the latter, incision and drainage was performed and the problem resolved without additional operations. Resorbable fixation system is an alternative to titanium products in the setting of pediatric facial fractures without complications involving delayed union or malunion. The combination of intermaxillary fixation and RFS is not needed postoperatively for adequate fixation of mandible fractures. Resorbable fixation system is able to provide adequate internal fixation when both low-stress and high-stress craniofacial fractures occur simultaneously.

Split Fracture of the Posteromedial Tubercle of the Talus: Case Report and Proposed Classification System.

PubMed

Watanabe, Hiroshi; Majima, Tokifumi; Takahashi, Kenji; Kawaji, Hidemi; Takai, Shinro

We describe a rare case of a fracture of the medial tubercle of the posterior process of the talus in a 16-year-old male athlete who fell during basketball practice. The patient presented to our orthopedic clinic when pain and swelling had persisted despite 2 weeks of anti-inflammatory medication and rest. Computed tomography and magnetic resonance imaging scans revealed a fracture of the posteromedial tubercle of the talus and a small amount of retained fluid in the joint. Immobilization with a below-the-knee cast and non-weightbearing for 4 weeks, with a gradual return to full activity, was successful. At the 1-year follow-up evaluation, the patient expressed no complaints. Fracture of the posteromedial tubercle of the talus will usually result in a misdiagnosis or delayed diagnosis owing to the insidious onset of symptoms. We believe the present fracture configuration resulted from the vertical compression force that occurred on landing by posterior medial ankle impingement in plantarflexion-supination, modifying the conventional concept of the posteromedial tubercle fracture. We also present a suggested classification with a flowchart diagram. Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Anaesthesia for proximal femoral fracture in the UK: first report from the NHS Hip Fracture Anaesthesia Network.

PubMed

White, S M; Griffiths, R; Holloway, J; Shannon, A

2010-03-01

The aim of this audit was to investigate process, personnel and anaesthetic factors in relation to mortality among patients with proximal femoral fractures. A questionnaire was used to record standardised data about 1195 patients with proximal femoral fracture admitted to 22 hospitals contributing to the Hip Fracture Anaesthesia Network over a 2-month winter period. Patients were demographically similar between hospitals (mean age 81 years, 73% female, median ASA grade 3). However, there was wide variation in time from admission to operation (24-108 h) and 30-day postoperative mortality (2-25%). Fifty percent of hospitals had a mean admission to operation time < 48 h. Forty-two percent of operations were delayed: 51% for organisational; 44% for medical; and 4% for 'anaesthetic' reasons. Regional anaesthesia was administered to 49% of patients (by hospital, range = 0-82%), 51% received general anaesthesia and 19% of patients received peripheral nerve blockade. Consultants administered 61% of anaesthetics (17-100%). Wide national variations in current management of patients sustaining proximal femoral fracture reflect a lack of research evidence on which to base best practice guidance. Collaborative audits such as this provide a robust method of collecting such evidence.

DEVELOPMENT AND APPLICATION OF MATERIALS PROPERTIES FOR FLAW STABILITY ANALYSIS IN EXTREME ENVIRONMENT SERVICE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sindelar, R; Ps Lam, P; Andrew Duncan, A

Discovery of aging phenomena in the materials of a structure may arise after its design and construction that impact its structural integrity. This condition can be addressed through a demonstration of integrity with the material-specific degraded conditions. Two case studies of development of fracture and crack growth property data, and their application in development of in-service inspection programs for nuclear structures in the defense complex are presented. The first case study covers the development of fracture toughness properties in the form of J-R curves for rolled plate Type 304 stainless steel with Type 308 stainless steel filler in the applicationmore » to demonstrate the integrity of the reactor tanks of the heavy water production reactors at the Savannah River Site. The fracture properties for the base, weld, and heat-affected zone of the weldments irradiated at low temperatures (110-150 C) up to 6.4 dpa{sub NRT} and 275 appm helium were developed. An expert group provided consensus for application of the irradiated properties for material input to acceptance criteria for ultrasonic examination of the reactor tanks. Dr. Spencer H. Bush played a lead advisory role in this work. The second case study covers the development of fracture toughness for A285 carbon steel in high level radioactive waste tanks. The approach in this case study incorporated a statistical experimental design for material testing to address metallurgical factors important to fracture toughness. Tolerance intervals were constructed to identify the lower bound fracture toughness for material input to flaw disposition through acceptance by analysis.« less

Dynamic characterisation of the specific surface area for fracture networks

NASA Astrophysics Data System (ADS)

Cvetkovic, V.

2017-12-01

One important application of chemical transport is geological disposal of high-level nuclear waste for which crystalline rock is a prime candidate for instance in Scandinavia. Interconnected heterogeneous fractures of sparsely fractured rock such as granite, act as conduits for transport of dissolved tracers. Fluid flow is known to be highly channelized in such rocks. Channels imply narrow flow paths, adjacent to essentially stagnant water in the fracture and/or the rock matrix. Tracers are transported along channelised flow paths and retained by minerals and/or stagnant water, depending on their sorption properties; this mechanism is critical for rocks to act as a barrier and ultimately provide safety for a geological repository. The sorbing tracers are retained by diffusion and sorption on mineral surfaces, whereas non-sorbing tracers can be retained only by diffusion into stagnant water of fractures. The retention and transport properties of a sparsely fractured rock will primarily depend on the specific surface area (SSA) of the fracture network which is determined by the heterogeneous structure and flow. The main challenge when characterising SSA on the field-scale is its dependence on the flow dynamics. We first define SSA as a physical quantity and clarify its importance for chemical transport. A methodology for dynamic characterisation of SSA in fracture networks is proposed that relies on three sets of data: i) Flow rate data as obtained by a flow logging procedure; ii) transmissivity data as obtained by pumping tests; iii) fracture network data as obtained from outcrop and geophysical observations. The proposed methodology utilises these data directly as well as indirectly through flow and particle tracking simulations in three-dimensional discrete fracture networks. The methodology is exemplified using specific data from the Swedish site Laxemar. The potential impact of uncertainties is of particular significance and is illustrated for radionuclide attenuation. Effects of internal fracture heterogeneity vs fracture network heterogeneity, and of rock deformation, on the statistical properties of SSA are briefly discussed.

Structural Properties and Estimation of Delay Systems. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Kwong, R. H. S.

1975-01-01

Two areas in the theory of delay systems were studied: structural properties and their applications to feedback control, and optimal linear and nonlinear estimation. The concepts of controllability, stabilizability, observability, and detectability were investigated. The property of pointwise degeneracy of linear time-invariant delay systems is considered. Necessary and sufficient conditions for three dimensional linear systems to be made pointwise degenerate by delay feedback were obtained, while sufficient conditions for this to be possible are given for higher dimensional linear systems. These results were applied to obtain solvability conditions for the minimum time output zeroing control problem by delay feedback. A representation theorem is given for conditional moment functionals of general nonlinear stochastic delay systems, and stochastic differential equations are derived for conditional moment functionals satisfying certain smoothness properties.

Evaluation of the microstructure, secondary dendrite arm spacing, and mechanical properties of Al-Si alloy castings made in sand and Fe-Cr slag molds

NASA Astrophysics Data System (ADS)

Narasimha Murthy, I.; Babu Rao, J.

2017-07-01

The microstructure and mechanical properties of as-cast A356 (Al-Si) alloy castings were investigated. A356 alloy was cast into three different molds composed of sand, ferrochrome (Fe-Cr) slag, and a mixture of sand and Fe-Cr. A sodium silicate-CO2 process was used to make the necessary molds. Cylindrical-shaped castings were prepared. Cast products with no porosity and a good surface finish were achieved in all of the molds. These castings were evaluated for their metallography, secondary dendrite arm spacing (SDAS), and mechanical properties, including hardness, compression, tensile, and impact properties. Furthermore, the tensile and impact samples were analyzed by fractography. The results show that faster heat transfer in the Fe-Cr slag molds than in either the silica sand or mixed molds led to lower SDAS values with a refined microstructure in the products cast in Fe-Cr slag molds. Consistent and enhanced mechanical properties were observed in the slag mold products than in the castings obtained from either sand or mixed molds. The fracture surface of the slag mold castings shows a dimple fracture morphology with a transgranular fracture nature. However, the fracture surfaces of the sand mold castings display brittle fracture. In conclusion, products cast in Fe-Cr slag molds exhibit an improved surface finish and enhanced mechanical properties compared to those of products cast in sand and mixed molds.

Fracture Anisotropy and Toughness in the Mancos Shale: Implications for crack-growth geometry

NASA Astrophysics Data System (ADS)

Chandler, M. R.; Meredith, P. G.; Brantut, N.; Crawford, B. R.

2013-12-01

The hydraulic fracturing of gas-shales has drawn attention to the fundamental fracture properties of shales. Fracture propagation is dependent on a combination of the in-situ stress field, the fracturing fluid and pressure, and the mechanical properties of the shale. However, shales are strongly anisotropic, and there is a general paucity of available experimental data on the anisotropic mechanical properties of shales in the scientific literature. The mode-I stress intensity factor, KI, quantifies the concentration of stress at crack tips. The Fracture Toughness of a linear elastic material is then defined as the critical value of this stress intensity factor; KIc, beyond which rapid catastrophic crack growth occurs. However, shales display significant non-linearity, which produces hysteresis during experimental cyclic loading. This allows for the calculation of a ductility coefficient using the residual displacement after successive loading cycles. From this coefficient, a ductility corrected Fracture Toughness value, KIcc can be determined. In the Mancos Shale this ductility correction can be as large as 60%, giving a Divider orientation KIcc value of 0.8 MPa.m0.5. Tensile strength and mode-I Fracture Toughness have been experimentally determined for the Mancos Shale using the Brazil Disk and Short-Rod methodologies respectively. The three principal fracture orientations; Arrester, Divider and Short-Transverse were all analysed. A significant anisotropy is observed in the tensile strength, with the Arrester value being 1.5 times higher than the Short-Transverse value. Even larger anisotropy is observed in the Fracture Toughness, with KIcc in the Divider and Arrester orientations being around 1.8 times that in the Short-Transverse orientation. For both tensile strength and fracture toughness, the Short-Transverse orientation, where the fracture propagates in the bedding plane in a direction parallel to the bedding, is found to have significantly lower values than the other two orientations. This anisotropy and variability in fracture properties is seen to cause deviation of the fracture direction during experiments on Arrester and Short-Transverse oriented samples, and can be expected to influence the geometry of propagating fractures. A comparison between the anisotropic tensile strength of the material and the crack-tip stress field in a transversely isotropic material has been used to develop a crack-tip deflection criterion in terms of the elasticity theory of cracks. This criterion suggests that a small perturbation in the incident angle of a mode-I crack propagating perpendicular to the bedding is likely to lead to a substantial deflection towards bedding-parallel (Short-Transverse) propagation. Further experimental work is currently underway on anisotropic Fracture Toughness measurements at elevated pressures and temperatures, simulating conditions in Shale Gas reservoirs at depths up to around 4km.

Multi-scale fracture networks within layered shallow water tight carbonates

NASA Astrophysics Data System (ADS)

Panza, Elisa; Agosta, Fabrizio; Rustichelli, Andrea; Vinciguerra, Sergio; Zambrano, Miller; Prosser, Giacomo; Tondi, Emanuele

2015-04-01

The work is aimed at deciphering the contribution of background deformation and persistent fracture zones on the fluid flow properties of tight platform carbonates. Taking advantage of 3D exposures present in the Murge area of southern Italy, the fracture networks crosscutting at different scales the layered Cretaceous limestone of the Altamura Fm. were analyzed. The rock multi-layer is characterized by 10's of cm-thick, sub-horizontal, laterally continuous carbonate beds. Each bed commonly represents a shallowing-upward peritidal cycle made up of homogeneous micritic limestones grading upward to cm-thick stromatolitic limestones and/or fenestral limestones. The bed interfaces are formed by sharp maximum flooding surfaces. Porosity measurements carried out on 40 limestone samples collected from a single carbonate bed show values ranging between 0,5% and 5,5%. Background deformation includes both stratabound and non-stratabound fractures. The former elements consist of bed-perpendicular joints and sheared joints, which are confined within a single bed and often displace small, bed-parallel stylolites. Non-stratabound fractures consist of incipient, cm offset, sub-vertical strike-slip faults, which crosscut the bed interfaces. The aforementioned elements are often confined within individual bed-packages, which are identified by presence of pronounced surfaces locally marked by veneers of reddish clayey paleosoils. Persistent fracture zones consist of 10's of m-high, 10's of cm-offset strike-slip faults that offset the bed-package interfaces and are confined within individual bed-packages association. Laterally discontinuous, cm- to a few m-thick paleokarstic breccia levels separate the different bed-packages associations. Persistent fracture zones include asymmetric fractured damage zones and mm-thick veneers of discontinuous fault rocks. The fracture networks that pervasively crosscut the study limestone multi-layer are investigated by mean of scanline and scanarea methodologies. The dimensional, spatial and scaling properties of both stratabound and non-stratabound fractures are documented along single beds and bed-packages, respectively. Persistent fracture zones are studied from individual bed-package associations. By computing the intensity, height distribution, aspect ratio, aperture of each fracture/fault set, DFN (Discrete Fracture Network) models are built for the aforementioned different scales of observation. DFN models of single beds and bed-packages include stratabound and non-stratabound fractures. Differently, the DFN model of a bed-packages association also includes persistent fracture zones and related damage zones. To check the results of our computations, we also build up a smaller scale, 1m3 geocellular volume in which fractures are inserted one at time in the model. All DFN models do not include the matrix porosity. Porosity and 3D permeability (Kx, Ky, Kz) values are obtained as outputs of the DFN models. The results are consistent with the most prominet set of non-stratabound fractures being the major control on the petrophysical properties of both single beds and bed-packages. As expected, the persistent fractures zones strongly affect both porosity and permeability of the bed-packages association. The results of ongoing laboratory analyses on representative limestone samples not only will provide a quantitative assessment of the physical properties of the matrix in terms of porosity and permeability, but also will shed new light on the geometry, density and anisotropy of microfractures and their role on fluid flow properties.

Determination of Dynamic Fracture Toughness Properties of Rail Steels

DOT National Transportation Integrated Search

1987-11-01

Motivated by the occurrence of a long-running rail web fracture in service, dynamic fracture mechanics research was undertaken to (1) quantify the crack driving force due to the residual stresses induced by roller straightening operations, (2) determ...

Fishtail deformity--a delayed complication of distal humeral fractures in children.

PubMed

Narayanan, Srikala; Shailam, Randheer; Grottkau, Brian E; Nimkin, Katherine

2015-06-01

Concavity in the central portion of the distal humerus is referred to as fishtail deformity. This entity is a rare complication of distal humeral fractures in children. The purpose of this study is to describe imaging features of post-traumatic fishtail deformity and discuss the pathophysiology. We conducted a retrospective analysis of seven cases of fishtail deformity after distal humeral fractures. Seven children ages 7-14 years (five boys, two girls) presented with elbow pain and history of distal humeral fracture. Four of the seven children had limited range of motion. Five children had prior grade 3 supracondylar fracture treated with closed reduction and percutaneous pinning. One child had a medial condylar fracture and another had a lateral condylar fracture; both had been treated with conservative casting. All children had radiographs, five had CT and three had MRI. All children had a concave central defect in the distal humerus. Other imaging features included joint space narrowing with osteophytes and subchondral cystic changes in four children, synovitis in one, hypertrophy or subluxation of the radial head in three and proximal migration of the ulna in two. Fishtail deformity of the distal humerus is a rare complication of distal humeral fractures in children. This entity is infrequently reported in the radiology literature. Awareness of the classic imaging features can result in earlier diagnosis and appropriate treatment.

The importance of early operative treatment in open fractures of the fingers.

PubMed

Ng, Tim; Unadkat, Jignesh; Bilonick, Richard A; Wollstein, Ronit

2014-04-01

Current guidelines suggest early surgical treatment of open fractures. This rule in open hand fractures is not well supported and may be practically difficult to observe. Furthermore, desirable washout can be obtained in the emergency department (ED). The purpose of this study was to determine the importance of early surgery in our institution. Seventy patients with open fractures of the hand were retrospectively reviewed for demographics, fracture characteristics, and complications. Statistical analysis included univariate analysis, Fisher exact test, and Akaike information criterion. Intravenous antibiotics were administered early in 53 (75.7%) patients. Mean (SD) time to surgery was 2.3 (134.9) hours. The infection rate was 11.4%. No significant relationship was found between fracture type, finger involved, hand dominance, comorbidities, and infection. Antibiotic administration was significantly related to infection (P = 0.007), whereas time to surgery was not (P = 0.33). Age was weakly related to infection (P = 0.08). Administration of intravenous antibiotics in the ED was the most significant factor in preventing infection, whereas the time to operation was not significant. Because a thorough washout and debridement can be performed on open hand fractures in the ED due to the ability to provide adequate anesthesia, the actual time to surgery may possibly be delayed without increasing the risk of infection. Future prospective studies may allow for better guidelines for the treatment of open hand fractures.

The effects of dolomitization on petrophysical properties and fracture distribution within rift-related carbonates (Hammam Faraun Fault Block, Suez Rift, Egypt)

NASA Astrophysics Data System (ADS)

Korneva, I.; Bastesen, E.; Corlett, H.; Eker, A.; Hirani, J.; Hollis, C.; Gawthorpe, R. L.; Rotevatn, A.; Taylor, R.

2018-03-01

Petrographic and petrophysical data from different limestone lithofacies (skeletal packstones, matrix-supported conglomerates and foraminiferal grainstones) and their dolomitized equivalents within a slope carbonate succession (Eocene Thebes Formation) of Hammam Faraun Fault Block (Suez Rift, Egypt) have been analyzed in order to link fracture distribution with mechanical and textural properties of these rocks. Two phases of dolomitization resulted in facies-selective stratabound dolostones extending up to two and a half kilometers from the Hammam Faraun Fault, and massive dolostones in the vicinity of the fault (100 metres). Stratabound dolostones are characterized by up to 8 times lower porosity and 6 times higher frequency of fractures compared to the host limestones. Precursor lithofacies type has no significant effect on fracture frequency in the stratabound dolostones. At a distance of 100 metres from the fault, massive dolostones are present which have 0.5 times porosity of precursor limestones, and lithofacies type exerts a stronger control on fracture frequency than the presence of dolomitization (undolomitized vs. dolomitized). Massive dolomitization corresponds to increased fracture intensity in conglomerates and grainstones but decreased fracture intensity in packstones. This corresponds to a decrease of grain/crystal size in conglomerates and grainstones and its increase in packstones after massive dolomitization. Since fractures may contribute significantly to the flow properties of a carbonate rock, the work presented herein has significant applicability to hydrocarbon exploration and production from limestone and dolostone reservoirs, particularly where matrix porosities are low.

Analysis of a mesoscale infiltration and water seepage test in unsaturated fractured rock: Spatial variabilities and discrete fracture patterns

USGS Publications Warehouse

Zhou, Q.; Salve, R.; Liu, H.-H.; Wang, J.S.Y.; Hudson, D.

2006-01-01

A mesoscale (21??m in flow distance) infiltration and seepage test was recently conducted in a deep, unsaturated fractured rock system at the crossover point of two underground tunnels. Water was released from a 3??m ?? 4??m infiltration plot on the floor of an alcove in the upper tunnel, and seepage was collected from the ceiling of a niche in the lower tunnel. Significant temporal and (particularly) spatial variabilities were observed in both measured infiltration and seepage rates. To analyze the test results, a three-dimensional unsaturated flow model was used. A column-based scheme was developed to capture heterogeneous hydraulic properties reflected by these spatial variabilities observed. Fracture permeability and van Genuchten ?? parameter [van Genuchten, M.T., 1980. A closed-form equation for predicting the hydraulic conductivity of unsaturated soils. Soil Sci. Soc. Am. J. 44, 892-898] were calibrated for each rock column in the upper and lower hydrogeologic units in the test bed. The calibrated fracture properties for the infiltration and seepage zone enabled a good match between simulated and measured (spatially varying) seepage rates. The numerical model was also able to capture the general trend of the highly transient seepage processes through a discrete fracture network. The calibrated properties and measured infiltration/seepage rates were further compared with mapped discrete fracture patterns at the top and bottom boundaries. The measured infiltration rates and calibrated fracture permeability of the upper unit were found to be partially controlled by the fracture patterns on the infiltration plot (as indicated by their positive correlations with fracture density). However, no correlation could be established between measured seepage rates and density of fractures mapped on the niche ceiling. This lack of correlation indicates the complexity of (preferential) unsaturated flow within the discrete fracture network. This also indicates that continuum-based modeling of unsaturated flow in fractured rock at mesoscale or a larger scale is not necessarily conditional explicitly on discrete fracture patterns. ?? 2006 Elsevier B.V. All rights reserved.

Melt fracture of linear low-density polyethylenes: Die geometry and molecular weight characteristics

NASA Astrophysics Data System (ADS)

Ebrahimi, Marzieh; Tomkovic, Tanja; Liu, Guochang; Doufas, Antonios A.; Hatzikiriakos, Savvas G.

2018-05-01

The melt fracture phenomena of three linear low-density polyethylenes are investigated as a function of die geometry (capillary, slit, and annular) and molecular weight and its distribution. The onset of melt fracture instabilities is determined by using capillary rheometry, mainly studying the extrudate appearance using optical microscopy. It is found that the onset of flow instabilities (melt fracture phenomena) is significantly affected by die geometry and molecular weight characteristics of the polymers. Use of annular die eliminates the stick-slip transition (oscillating melt fracture) and delays the onset of sharkskin to higher values of shear rate and shear stress. Moreover, it is shown that the molecular weight characteristics of the polymers are well correlated with critical conditions for the onset of flow instabilities based on a criterion proposed in the literature [A. Allal et al., "Relationships between molecular structure and sharkskin defect for linear polymers," J. Non-Newtonian Fluid Mech. 134, 127-135 (2006) and A. Allal and B. Vergnes, "Molecular design to eliminate sharkskin defect for linear polymers," J. Non-Newtonian Fluid Mech. 146, 45-50 (2007)].

Patellar Shape-Memory Fixator for the Treatment of Comminuted Fractures of the Inferior Pole of the Patella

NASA Astrophysics Data System (ADS)

Liu, Xin-Wei; Shang, Hui-Juan; Xu, Shuo-Gui; Wang, Zhi-Wei; Zhang, Chun-Cai; Fu, Qing-Ge

2011-07-01

Comminuted and displaced fractures of the inferior pole of the patella are not easy to reduce and it is difficult to fix the fragments soundly enough to allow early movement of the knee. The purpose of this study is to evaluate the clinical effectiveness of the internal fixation technique with Patellar Shape-Memory Fixator (PSMF) in acute comminuted fractures of the inferior pole of the patella. We retrospectively studied 25 patients with comminuted fractures of the inferior pole of the patella who were treated with PSMF and followed up for a mean period of 26 months (14 to 60). All the fractures healed at a mean of 6 weeks (5 to 7). The mean grading at the final follow-up was 29.5 points (27 to 30) using the Bostman score, with no observable restriction of movement. No breakage of the PSMF or infection occurred. No delayed union, nonunion, and infection were seen. This technique preserved the length of the patella, reduced the comminuted fragments of the inferior pole and avoided long-term immobilization of the knee.

Shaft-Condylar Angle for surgical correction in neglected and displaced lateral humeral condyle fracture in children.

PubMed

Mulpruek, Pornchai; Angsanuntsukh, Chanika; Woratanarat, Patarawan; Sa-Ngasoongsong, Paphon; Tawonsawatruk, Tulyapruek; Chanplakorn, Pongsthorn

2015-09-01

To assess the outcome after using the Shaft-Condylar angle (SCA) as intraoperative reference for sagittal plane correction in displaced lateral humeral condyle fractures in children presented 3-weeks after injury. Ten children, with delayed presentation of a displaced lateral humeral condyle fracture and undergoing surgery during 1999-2011, were reviewed. The goal was to obtain a smooth articular surface with an intraoperative SCA of nearly 40° and nearest-anatomical carrying angle. They were allocated into two groups according to the postoperative SCA [Good-reduction group (SCA=30-50°), and Bad-reduction group (SCA<30°, >50°)] and the final outcomes were then compared. All fractures united without avascular necrosis. The Good-reduction group (n=7) showed a significant improvement in final range of motion and functional outcome compared to the Bad-reduction group (n=3) (p=0.02). However, there was no significant difference in pain, carrying angle and overall outcome between both groups. SCA is a possible intraoperative reference for sagittal alignment correction in late presented displaced lateral humeral condyle fractures.

Local delivery of HMGB1 in gelatin sponge scaffolds combined with mesenchymal stem cell sheets to accelerate fracture healing.

PubMed

Xue, Deting; Zhang, Wei; Chen, Erman; Gao, Xiang; Liu, Ling; Ye, Chenyi; Tan, Yanbin; Pan, Zhijun; Li, Hang

2017-06-27

Fracture nonunion and delayed union continue to pose challenges for orthopedic surgeons. In the present study, we combined HMGB1 gelatin sponges with MSC sheets to promote bone healing after surgical treatment of rat tibial fractures. The HMGB1 gelatin sponge scaffolds supported the expansion of mesenchymal stem cells (MSCs) and promoted the osteogenic differentiation of MSCs and MSC sheets. Lentiviral vectors were then used to overexpress HMGB1 in MSCs. The results indicated that HMGB1 promotes the osteogenic differentiation of MSCs through the STAT3 pathway. Both siRNA and a STAT3 inhibitor downregulated STAT3, further confirming that HMGB1 induces the osteogenic differentiation of MSCs partly via the STAT3 signal pathway. In a rat tibial osteotomy model, we demonstrated the ability of HMGB1 gelatin sponge scaffolds to increase bone formation. The addition of MSC sheets further enhanced fracture healing. These findings support the use of HMGB1-loaded gelatin sponge scaffolds combined with MSC sheets to enhance fracture healing after surgical intervention.

Local delivery of HMGB1 in gelatin sponge scaffolds combined with mesenchymal stem cell sheets to accelerate fracture healing

PubMed Central

Xue, Deting; Zhang, Wei; Chen, Erman; Gao, Xiang; Liu, Ling; Ye, Chenyi; Tan, Yanbin; Pan, Zhijun; Li, Hang

2017-01-01

Fracture nonunion and delayed union continue to pose challenges for orthopedic surgeons. In the present study, we combined HMGB1 gelatin sponges with MSC sheets to promote bone healing after surgical treatment of rat tibial fractures. The HMGB1 gelatin sponge scaffolds supported the expansion of mesenchymal stem cells (MSCs) and promoted the osteogenic differentiation of MSCs and MSC sheets. Lentiviral vectors were then used to overexpress HMGB1 in MSCs. The results indicated that HMGB1 promotes the osteogenic differentiation of MSCs through the STAT3 pathway. Both siRNA and a STAT3 inhibitor downregulated STAT3, further confirming that HMGB1 induces the osteogenic differentiation of MSCs partly via the STAT3 signal pathway. In a rat tibial osteotomy model, we demonstrated the ability of HMGB1 gelatin sponge scaffolds to increase bone formation. The addition of MSC sheets further enhanced fracture healing. These findings support the use of HMGB1-loaded gelatin sponge scaffolds combined with MSC sheets to enhance fracture healing after surgical intervention. PMID:28431400

High performance thermoplastics - A review of neat resin and composite properties

NASA Technical Reports Server (NTRS)

Johnston, Norman J.; Hergenrother, Paul M.

1987-01-01

A review was made of the principal thermoplastics used to fabricate high performance composites. Neat resin tensile and fracture toughness properties, glass transition temperatures (Tg), crystalline melt temperatures (Tm) and approximate processing conditions are presented. Mechanical properties of carbon fiber composites made from many of these thermoplastics are given, including flexural, longitudinal tensile, transverse tensile and in-plane shear properties as well as short beam shear and compressive strengths and interlaminar fracture toughness.

Percutaneous locking plates for fractures of the distal tibia: our experience and a review of the literature.

PubMed

Ahmad, Mudussar Abrar; Sivaraman, Alagappan; Zia, Ahmed; Rai, Amarjit; Patel, Amratlal D

2012-02-01

Distal tibial metaphyseal fractures pose many complexities. This study assessed the outcomes of distal tibial fractures treated with medial locking plates. Eighteen patients were selected based on the fracture pattern and classified using the AO classification and stabilized with an AO medial tibial locking plate. Time to fracture union, complications, and outcomes were assessed with the American Orthopedic Foot and Ankle Society Ankle score at 12 months. Sixteen of the 18 patients achieved fracture union, with 1 patient lost to follow-up. Twelve fractures united within 24 weeks, with an average union time of 23.1 weeks. Three delayed unions, two at 28 weeks and one at 56 weeks. The average time to union was 32 weeks in the smokers and 15.3 weeks in the nonsmokers. Five of the 18 patients (27%) developed complications. One superficial wound infection, and one chronic wound infection, resulting in nonunion at 56 weeks, requiring revision. Two patients required plate removal, one after sustaining an open fracture at the proximal end of the plate 6 months after surgery (postfracture union)and the other for painful hardware. One patient had implant failure of three proximal diaphyseal locking screws at the screwhead/neck junction, but successful fracture union. The average American Orthopedic Foot and Ankle Society ankle score was 88.8 overall, and 92.1 in fractures that united within 24 weeks. Distal tibial locking plates have high fracture union rates, minimum soft tissue complications, and good functional outcomes. The literature shows similar fracture union and complication rates in locking and nonlocking plates. Copyright © 2012 by Lippincott Williams & Wilkins

High revision rate but good healing capacity of atypical femoral fractures. A comparison with common shaft fractures.

PubMed

Schilcher, Jörg

2015-12-01

Healing of complete, atypical femoral fractures is thought to be impaired, but the evidence is weak and appears to be based on the delayed healing observed in patients with incomplete atypical fractures. Time until fracture healing is difficult to assess, therefore we compared the reoperation rates between women with complete atypical femoral fractures and common femoral shaft fractures. We searched the orthopaedic surgical registry in Östergötland County for patients with subtrochanteric and femoral shaft fractures (ICD-10 diagnosis codes S72.2, S72.3 and M84.3F) between January 1st 2007 and December 31st 2013. Out of 895 patients with surgically treated femoral shaft fractures, 511 were women 50 years of age or older. Among these we identified 24 women with atypical femoral shaft fractures, and 71 with common shaft fractures. Reoperations were performed in 6 and 5 patients, respectively, odds ratio 4.4 (95% CI 1.2 to 16.1). However, 5 reoperations in the atypical fracture group could not be ascribed to poor healing. In 3 patients the reoperation was due to a new fracture proximal to a standard intramedullary nail. In 2 patients the distal locking screws were removed due to callus formation that was deemed incomplete 5 months post-operatively. The one patient with poor healing showed faint callus formation at 5 months when the fracture was dynamised and callus remained sparse at 11 months. Among patients with common shaft fractures, 2 reoperations were performed to remove loose screws, 2 because of peri-implant fractures and 1 reoperation due to infection. Reoperation rates in patients with complete atypical femoral fractures are higher than in patients with common shaft fractures. The main reason for failure was peri-implant fragility fractures which might be prevented with the use of cephalomedullary nails at the index surgery. Fracture healing however, seems generally good. A watchful waiting approach is advocated in patients with fractures that appear to heal slowly. Copyright © 2015 Elsevier Ltd. All rights reserved.

Predictors of Postoperative Wound Necrosis Following Primary Wound Closure of Open Ankle Fractures.

PubMed

Ovaska, Mikko T; Madanat, Rami; Mäkinen, Tatu J

2016-04-01

Most open malleolar ankle fracture wounds can be closed primarily after meticulous debridement. However, the development of wound necrosis following operative treatment of open malleolar ankle fractures can have catastrophic consequences. The aim of this study was to identify risk factors predisposing to postoperative wound necrosis following primary wound closure of open malleolar ankle fractures. A total of 137 patients with open malleolar ankle fractures were identified. The open fracture wound was primarily closed in 110 of 137 (80%) patients, and postoperative wound necrosis occurred in 18 (16%) of these patients. These patients were compared to the open fracture patients without wound necrosis. Twenty possible risk factors for the development of wound necrosis were studied with logistic regression analysis. The variables that were independently associated with an increased risk for postoperative wound necrosis included ASA class ≥2, Gustilo grade III open injury, and the use of pulsatile lavage at index surgery. Our study showed that ASA class ≥2, Gustilo grade III open injury, and the use of pulsatile lavage at index surgery were the most important factors predisposing to postoperative wound necrosis following primary wound closure of open malleolar ankle fractures. The findings warrant a further study specifically comparing primary and delayed wound closure in patients with Gustilo grade III open malleolar ankle fractures and different ASA classes. Also, the role of pulsatile lavage should be re-evaluated. Level III, retrospective comparative series. © The Author(s) 2016.

Basic concepts regarding fracture healing and the current options and future directions in managing bone fractures.

PubMed

Bigham-Sadegh, Amin; Oryan, Ahmad

2015-06-01

Fracture healing is a complex physiological process, which involves a well-orchestrated series of biological events. Repair of large bone defects resulting from trauma, tumours, osteitis, delayed unions, non-unions, osteotomies, arthrodesis and multifragmentary fractures is a current challenge of surgeons and investigators. Different therapeutic modalities have been developed to enhance the healing response and fill the bone defects. Different types of growth factors, stem cells, natural grafts (autografts, allografts or xenografts) and biologic- and synthetic-based tissue-engineered scaffolds are some of the examples. Nevertheless, these organic and synthetic materials and therapeutic agents have some significant limitations, and there are still no well-approved treatment modalities to meet all the expected requirements. Bone tissue engineering is a newer option than the traditional grafts and may overcome many limitations of the bone graft. To select an appropriate treatment strategy in achieving a successful and secure healing, more information concerning injuries of bones, their healing process and knowledge of the factors involved are required. The main goals of this work are to present different treatment modalities of the fractured bones and to explain how fractures normally heal and what factors interfere with fracture healing. This study provides an overview of the processes of fracture healing and discusses the current therapeutic strategies that have been claimed to be effective in accelerating fracture healing. © 2014 The Authors. International Wound Journal © 2014 Medicalhelplines.com Inc and John Wiley & Sons Ltd.

Is Bone Grafting Necessary in the Treatment of Malunited Distal Radius Fractures?

PubMed Central

Disseldorp, Dominique J. G.; Poeze, Martijn; Hannemann, Pascal F. W.; Brink, Peter R. G.

2015-01-01

Background Open wedge osteotomy with bone grafting and plate fixation is the standard procedure for the correction of malunited distal radius fractures. Bone grafts are used to increase structural stability and to enhance new bone formation. However, bone grafts are also associated with donor site morbidity, delayed union at bone–graft interfaces, size mismatch between graft and osteotomy defect, and additional operation time. Purpose The goal of this study was to assess bone healing and secondary fracture displacement in the treatment of malunited distal radius fractures without the use of bone grafting. Methods Between January 1993 and December 2013, 132 corrective osteotomies and plate fixations without bone grafting were performed for malunited distal radius fractures. The minimum follow-up time was 12 months. Primary study outcomes were time to complete bone healing and secondary fracture displacement. Preoperative and postoperative radiographs during follow-up were compared with each other, as well as with radiographs of the uninjured side. Results All 132 osteotomies healed. In two cases (1.5%), healing took more than 4 months, but reinterventions were not necessary. No cases of secondary fracture displacement or hardware failure were observed. Significant improvements in all radiographic parameters were shown after corrective osteotomy and plate fixation. Conclusion This study shows that bone grafts are not required for bone healing and prevention of secondary fracture displacement after corrective osteotomy and plate fixation of malunited distal radius fractures. Level of evidence Therapeutic, level IV, case series with no comparison group PMID:26261748

Effects of aggregate gradation, aggregate type, and SBS polymer-modified binder on Florida HMAC fracture energy properties : final report, March 2009.

DOT National Transportation Integrated Search

2009-03-01

"The primary objective of this research study was to evaluate the fracture mechanics properties of HMA concrete for Superpave mixtures. An experimental program was performed on asphalt mixtures with various types of materials. The laboratory testing ...

Development of a quality control test procedure for characterizing fracture properties of asphalt mixtures.

DOT National Transportation Integrated Search

2011-06-01

The main objective of this study is to investigate the use of the semi-circular bend (SCB) : test as a quality assurance/quality control (QA/QC) measure for field construction. : Comparison of fracture properties from the SCB test and fatigue beam te...

A Numerical Study of Factors Affecting Fracture-Fluid Cleanup and Produced Gas/Water in Marcellus Shale: Part II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seales, Maxian B.; Dilmore, Robert; Ertekin, Turgay

Horizontal wells combined with successful multistage-hydraulic-fracture treatments are currently the most-established method for effectively stimulating and enabling economic development of gas-bearing organic-rich shale formations. Fracture cleanup in the stimulated reservoir volume (SRV) is critical to stimulation effectiveness and long-term well performance. But, fluid cleanup is often hampered by formation damage, and post-fracture well performance frequently falls to less than expectations. A systematic study of the factors that hinder fracture-fluid cleanup in shale formations can help optimize fracture treatments and better quantify long-term volumes of produced water and gas. Fracture-fluid cleanup is a complex process influenced by mutliphase flow through porousmore » media (relative permeability hysteresis, capillary pressure), reservoir-rock and -fluid properties, fracture-fluid properties, proppant placement, fracture-treatment parameters, and subsequent flowback and field operations. Changing SRV and fracture conductivity as production progresses further adds to the complexity of this problem. Numerical simulation is the best and most-practical approach to investigate such a complicated blend of mechanisms, parameters, their interactions, and subsequent effect on fracture-fluid cleanup and well deliverability. Here, a 3D, two-phase, dual-porosity model was used to investigate the effect of mutliphase flow, proppant crushing, proppant diagenesis, shut-in time, reservoir-rock compaction, gas slippage, and gas desorption on fracture-fluid cleanup and well performance in Marcellus Shale. Our findings have shed light on the factors that substantially constrain efficient fracture-fluid cleanup in gas shales, and we have provided guidelines for improved fracture-treatment designs and water management.« less

A Numerical Study of Factors Affecting Fracture-Fluid Cleanup and Produced Gas/Water in Marcellus Shale: Part II

DOE PAGES

Seales, Maxian B.; Dilmore, Robert; Ertekin, Turgay; ...

2017-04-01

Horizontal wells combined with successful multistage-hydraulic-fracture treatments are currently the most-established method for effectively stimulating and enabling economic development of gas-bearing organic-rich shale formations. Fracture cleanup in the stimulated reservoir volume (SRV) is critical to stimulation effectiveness and long-term well performance. But, fluid cleanup is often hampered by formation damage, and post-fracture well performance frequently falls to less than expectations. A systematic study of the factors that hinder fracture-fluid cleanup in shale formations can help optimize fracture treatments and better quantify long-term volumes of produced water and gas. Fracture-fluid cleanup is a complex process influenced by mutliphase flow through porousmore » media (relative permeability hysteresis, capillary pressure), reservoir-rock and -fluid properties, fracture-fluid properties, proppant placement, fracture-treatment parameters, and subsequent flowback and field operations. Changing SRV and fracture conductivity as production progresses further adds to the complexity of this problem. Numerical simulation is the best and most-practical approach to investigate such a complicated blend of mechanisms, parameters, their interactions, and subsequent effect on fracture-fluid cleanup and well deliverability. Here, a 3D, two-phase, dual-porosity model was used to investigate the effect of mutliphase flow, proppant crushing, proppant diagenesis, shut-in time, reservoir-rock compaction, gas slippage, and gas desorption on fracture-fluid cleanup and well performance in Marcellus Shale. Our findings have shed light on the factors that substantially constrain efficient fracture-fluid cleanup in gas shales, and we have provided guidelines for improved fracture-treatment designs and water management.« less

Mechanical property studies of human gallstones.

PubMed

Stranne, S K; Cocks, F H; Gettliffe, R

1990-08-01

The recent development of gallstone fragmentation methods has increased the significance of the study of the mechanical properties of human gallstones. In the present work, fracture strength data and microhardness values of gallstones of various chemical compositions are presented as tested in both dry and simulated bile environments. Generally, both gallstone hardness and fracture strength values were significantly less than kidney stone values found in previous studies. However, a single calcium carbonate stone was found to have an outer shell hardness exceeding those values found for kidney stones. Diametral compression measurements in simulated bile conclusively demonstrated low gallstone fracture strength as well as brittle fracture in the stones tested. Based on the results of this study, one may conclude that the wide range of gallstone microhardnesses found may explain the reported difficulties previous investigators have experienced using various fragmentation techniques on specific gallstones. Moreover, gallstone mechanical properties may be relatively sensitive to bile-environment composition.

A prospective study about the preoperative total blood loss in older people with hip fracture.

PubMed

Wu, Jie-Zhou; Liu, Peng-Cheng; Ge, Wei; Cai, Ming

2016-01-01

Our study is to confirm that hemoglobin (Hb) level is significantly reduced before operation in elderly patients with hip fracture and to specify potential amounts of bleeding and Hb decline in different types of fractures. A prospective analysis was made on the clinical data of 349 patients with both a diagnosis of hip fracture and an operative delay of greater than 72 hours between April 2014 and February 2016. Hb concentration was measured on a daily basis before the surgery. Patients were grouped according to the type of fracture (intracapsular and extracapsular) for calculation of the total blood loss (TBL). All data analyses were done by SPSS version 21 software. There was a significant decrease preoperatively in the Hb concentration of nearly 21.55 g/L (standard error of the mean [SEM] 7.67) in patients with extracapsular hip fractures and nearly 15.63 g/L (SEM 6.01) in patients with intracapsular hip fractures. The preoperative TBL in patients with extracapsular fracture was significantly larger compared to that in patients with intracapsular fracture (790.3 mL and 581.7 mL, respectively, P <0.05 using Student's t -test). We found no significant difference in the preoperative TBL between the male and female groups. Hip fracture patients have an obvious blood loss after the injury, yet prior to the surgery the Hb levels were found to be normal. Anesthetic and orthopedic staff should pay additional attention to the problem of low preoperative Hb concentration, even if the initial Hb level was apparently normal.

Malunion of Long-Bone Fractures in a Conflict Zone in the Democratic Republic of Congo.

PubMed

Bauhahn, Grace; Veen, Harald; Hoencamp, Rigo; Olim, Nelson; Tan, Edward C T H

2017-09-01

Malunion is a well-recognized complication of long-bone fractures which accounts for more than 25% of injuries in conflict zones. The aim of this study was to investigate the rate of malunion sustained by casualties with penetrating gunshot wounds in an International Committee of the Red Cross (ICRC) surgical substitution project in the Democratic Republic of Congo (DRC) and compare these results with current literature. A retrospective cohort study was performed. All patients admitted to the ICRC facility between the periods of 01.10.2014 and 31.12.2015 with long-bone fractures caused by gunshot wound were included, and data were collected retrospectively from the patient's hospital notes. A total of 191 fractures caused by gunshot were treated in the DRC at the ICRC surgical substitution project during the study period. On average, the fractures were 3 days old on admission and were all open, with 62% also being comminuted. The ICRC management protocol, which emphasizes debridement, antibiotic prophylaxis and conservative fracture stabilization, was followed in all cases. Forty-eight percentage of the fractures were finally classified as 'union without complication'; however, 17% were classified as 'malunion'. This study indicates that open long-bone fractures that are managed by the ICRC surgical substitution project in DRC may have an increased likelihood of malunion as compared to long-bone fractures treated in developed countries. Patient delay and mechanism of injury may have caused increased rates of infection which are likely behind these increased rates of malunion, alongside the lack of definitive fracture treatment options made available to the surgical team.

Using external and internal locking plates in a two-stage protocol for treatment of segmental tibial fractures.

PubMed

Ma, Ching-Hou; Tu, Yuan-Kun; Yeh, Jih-Hsi; Yang, Shih-Chieh; Wu, Chin-Hsien

2011-09-01

The tibial segmental fractures usually follow high-energy trauma and are often associated with many complications. We designed a two-stage protocol for these complex injuries. The aim of this study was to assess the outcome of tibial segmental fractures treated according to this protocol. A prospective series of 25 consecutive segmental tibial fractures were treated using a two-stage procedure. In the first stage, a low-profile locking plate was applied as an external fixator to temporarily immobilize the fractures after anatomic reduction had been achieved followed by soft-tissue reconstruction. The second stage involved definitive internal fixation with a locking plate using a minimally invasive percutaneous plate osteosynthesis technique. The median follow-up was 32 months (range, 20-44 months). All fractures achieved union. The median time for the proximal fracture union was 23 weeks (range, 12-30 weeks) and that for distal fracture union was 27 weeks (range, 12-46 weeks; p = 0.08). Functional results were excellent in 21 patients and good in 4 patients. There were three cases of delayed union of distal fracture. Valgus malunion >5 degrees occurred in two patients, and length discrepancy >1 cm was observed in two patients. Pin tract infection occurred in three patients. Use of the two-stage procedure for treatment of segmental tibial fractures is recommended. Surgeons can achieve good reduction with stable temporary fixation, soft-tissue reconstruction, ease of subsequent definitive fixation, and high union rates. Our patients obtained excellent knee and ankle joint motion, good functional outcomes, and a comfortable clinical course.

The effects of axial displacement on fracture callus morphology and MSC homing depend on the timing of application.

PubMed

Weaver, Aaron S; Su, Yu-Ping; Begun, Dana L; Miller, Joshua D; Alford, Andrea I; Goldstein, Steven A

2010-07-01

The local mechanical environment and the availability of mesenchymal stem cells (MSC) have both been shown to be important factors in bone fracture healing. This study was designed to investigate how the timing of an applied axial displacement across a healing fracture affects callus properties as well as the migration of systemically introduced MSC. Bilateral osteotomies were created in male, Sprague-Dawley rats. Exogenous MSC were injected via the tail vein, and a controlled micro-motion was applied to one defect starting 0, 3, 10, or 24 days after surgery. The results showed that fractures stimulated 10 days after surgery had more mineral, less cartilage, and greater mechanical properties at 48 days than other groups. Populations of MSC were found in osteotomies 48 days after surgery, with the exception of the group that was stimulated 10 days after surgery. These results demonstrate that the timing of mechanical stimulation affects the physical properties of the callus and the migration of MSC to the fracture site. Published by Elsevier Inc.

Physical Properties of Fractured Porous Media

NASA Astrophysics Data System (ADS)

Mohammed, T. E.; Schmitt, D. R.

2015-12-01

The effect of fractures on the physical properties of porous media is of considerable interest to oil and gas exploration as well as enhanced geothermal systems and carbon capture and storage. This work represents an attempt to study the effect fractures have on multiple physical properties of rocks. An experimental technique to make simultaneous electric and ultrasonic measurements on cylindrical core plugs is developed. Aluminum end caps are mounted with ultrasonic transducers to transmit pules along the axis of the cylinder while non-polarizing electrodes are mounted on the sides of the core to make complex conductivity measurements perpendicular to the cylinder axis. Electrical measurements are made by applying a sinusoidal voltage across the measurement circuit that consist of a resister and the sample in series. The magnitude and phase of the signal across the sample is recorded relative to the input signal across a range of frequencies. Synthetic rock analogs are constructed using sintered glass beads with fractures imbedded in them. The fracture location, size and orientation are controlled and each fractured specimen has an unfractured counterpart. Porosity, Permeability, electrical conductivity and ultrasonic velocity measurements are conducted on each sample with the complex electrical conductivities recorded at frequencies from 10hz to 1 Mhz. These measurements allow us to examine the changes induced by these mesoscale fractures on the embedding porous medium. Of particular interest is the effect of fracture orientation on electrical conductivity of the rock. Seismic anisotropy caused by fractures is a well understood phenomenon with many rock physics models dedicated to its understanding. The effect of fractures on electrical conductivity is less well understood with electrical anisotropy scarcely investigated in the literature. None the less, using electrical conductivity to characterize fractures can add an extra constraint to characterization based on seismic response. As well, the formal similarity between electrical conductivity and permeability can be utilized to help optimize injection and production strategies.

Numerical study of transitional flow in fractures: the role of roughness on the road to turbulence

NASA Astrophysics Data System (ADS)

Linga, G.; Mathiesen, J.

2017-12-01

In aquifers and petroleum reservoirs, fractures are ubiquitous, and the majority of the fluid transport in such systems often occurs through fracture networks. Knowledge of the flow properties in the single fractures that together form the networks is hence necessary for safe operation downhole. Non-linear, high-velocity flow in such systems is of particular importance for geothermics, since turbulent mixing is known to increase heat conduction by several orders of magnitude. This is of importance both in terms of storing and recovering heat from aquifers. On the other hand, flow in rough fractures is interesting from a turbulence perspective. The onset of turbulence in pipes and channels is a phenomenon that historically has received broad attention since the early experiments by Reynolds, and only during the last decades, the phenomenon is beginning to be fully understood. However, in the presence of roughness, much less is known. In this work, we present comprehensive numerical simulations of flow in synthetic rough channels, representing single fracture joints. Using the finite element method, we solve the full-fledged, time-dependent Navier-Stokes equations for flow in the channels, from laminar flow, through transitional, to turbulent flow. We link the descriptions of microscopic to macroscopic properties, using geometric properties such as effective aperture, paying particular attention to the role of inertia and roughness for the transport properties of the channels. Finally, we discuss implications of our study for the transition to turbulence in the presence of roughness.

Improving the mechanical properties of nano-hydroxyapatite

NASA Astrophysics Data System (ADS)

Khanal, Suraj Prasad

Hydroxyapatite (HAp) is an ideal bioactive material that is used in orthopedics. Chemical composition and crystal structure properties of HAp are similar to the natural bone hence it promotes bone growth. However, its mechanical properties of synthetic HAp are not sufficient for major load-bearing bone replacement. The potential of improving the mechanical properties of synthetic hydroxyapatite (HAp) by incorporating carboxyl functionalized single walled carbon nanotubes (CfSWCNT) and polymerized epsilon-caprolactam (nylon) is studied. The fracture toughness, tensile strength, Young's modulus, stiffness and fracture energy were studied for a series of HAp samples with CfSWCNT concentrations varying from 0 to 1.5 wt. % without, and with nylon addition. X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Differential Scanning Calorimetry (DSC) were used to characterize the samples. The fracture toughness and tensile test was performed under the standard protocol of ASTM D5045 and ASTM D638-02a respectively. Reproducible maximum values of (3.60 +/- 0.3) MPa.m1/2 for fracture toughness and 65.38 MPa for tensile strength were measured for samples containing 1 wt. % CfSWCNT and nylon. The Young's modulus, stiffness and fracture energy of the samples are 10.65 GPa, 1482.12 N/mm, and 644 J/m2 respectively. These values are comparable to those of the cortical bone. Further increase of the CfSWCNT content results to a decreased fracture toughness and tensile strength and formation of a secondary phase.

Fracture stimulation treatment design optimization: What can the NPV vs X{sub f} plot tell us?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huffman, C.H.; Harkrider, J.D.; Thompson, R.S.

1996-12-31

Fracture stimulation production response coupled with the hydrocarbon sales price determines the value of a fracture stimulation treatment. Many factors can significantly effect the production response of a fracture stimulated well. Some examples include stimulation fluid selection, proppant selection, pumping rates, rock properties, reservoir fluid properties, in-situ stresses, stress variations, on-site execution, post-treatment stimulation fluid recovery, and operating practices. The production response in economic terms portrays the net effect of these variables. This paper presents a case study that demonstrates how post-treatment evaluations expressed in economic terms can be used to assess the performance of stimulations and to guide futuremore » design choices.« less

Microstructural and mechanical characterization of postweld heat-treated thermite weld in rails

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ilic, N.; Jovanovic, M.T.; Todorovic, M.

1999-10-01

This paper describes a comparative study of the hardness characteristics, mechanical properties, microstructures, and fracture mechanisms of the thermite welded rail steel joints before and after heat treatment. It has been found that heat treatment of the welded joint improves the mechanical properties (UTS and elongation), and changes the fracture mechanism from brittle to ductile. Improved strength and elongation are attributed to the finer ferrite-pearlite microstructure and the different fracture mechanism. Microporosity and numerous inclusions were seen on the fracture surface of the welded joint. The chemical composition of the inclusions indicated that the molten thermite mixture had reacted withmore » the magnesite lining of the ladle and the feeder.« less

Tissue-level Mechanical Properties of Bone Contributing to Fracture Risk

PubMed Central

Nyman, Jeffry S.; Granke, Mathilde; Singleton, Robert C.; Pharr, George M.

2016-01-01

Tissue-level mechanical properties characterize mechanical behavior independently of microscopic porosity. Specifically, quasi-static nanoindentation provides measurements of modulus (stiffness) and hardness (resistance to yielding) of tissue at the length scale of the lamella, while dynamic nanoindentation assesses time-dependent behavior in the form of storage modulus (stiffness), loss modulus (dampening), and loss factor (ratio of the two). While these properties are useful in establishing how a gene, signaling pathway, or disease of interest affects bone tissue, they generally do not vary with aging after skeletal maturation or with osteoporosis. Heterogeneity in tissue-level mechanical properties or in compositional properties may contribute to fracture risk, but a consensus on whether the contribution is negative or positive has not emerged. In vivo indentation of bone tissue is now possible, and the mechanical resistance to microindentation has the potential for improving fracture risk assessment, though determinants are currently unknown. PMID:27263108

Tissue-Level Mechanical Properties of Bone Contributing to Fracture Risk.

PubMed

Nyman, Jeffry S; Granke, Mathilde; Singleton, Robert C; Pharr, George M

2016-08-01

Tissue-level mechanical properties characterize mechanical behavior independently of microscopic porosity. Specifically, quasi-static nanoindentation provides measurements of modulus (stiffness) and hardness (resistance to yielding) of tissue at the length scale of the lamella, while dynamic nanoindentation assesses time-dependent behavior in the form of storage modulus (stiffness), loss modulus (dampening), and loss factor (ratio of the two). While these properties are useful in establishing how a gene, signaling pathway, or disease of interest affects bone tissue, they generally do not vary with aging after skeletal maturation or with osteoporosis. Heterogeneity in tissue-level mechanical properties or in compositional properties may contribute to fracture risk, but a consensus on whether the contribution is negative or positive has not emerged. In vivo indentation of bone tissue is now possible, and the mechanical resistance to microindentation has the potential for improving fracture risk assessment, though determinants are currently unknown.

Borehole characterization of hydraulic properties and groundwater flow in a crystalline fractured aquifer of a headwater mountain watershed, Laramie Range, Wyoming

NASA Astrophysics Data System (ADS)

Ren, Shuangpo; Gragg, Samuel; Zhang, Ye; Carr, Bradley J.; Yao, Guangqing

2018-06-01

Fractured crystalline aquifers of mountain watersheds may host a significant portion of the world's freshwater supply. To effectively utilize water resources in these environments, it is important to understand the hydraulic properties, groundwater storage, and flow processes in crystalline aquifers and field-derived insights are critically needed. Based on borehole hydraulic characterization and monitoring data, this study inferred hydraulic properties and groundwater flow of a crystalline fractured aquifer in Laramie Range, Wyoming. At three open holes completed in a fractured granite aquifer, both slug tests and FLUTe liner profiling were performed to obtain estimates of horizontal hydraulic conductivity (Kh). Televiewer (i.e., optical and acoustic) and flowmeter logs were then jointly interpreted to identify the number of flowing fractures and fracture zones. Based on these data, hydraulic apertures were obtained for each borehole. Average groundwater velocity was then computed using Kh, aperture, and water level monitoring data. Finally, based on all available data, including cores, borehole logs, LIDAR topography, and a seismic P-wave velocity model, a three dimensional geological model of the site was built. In this fractured aquifer, (1) borehole Kh varies over ∼4 orders of magnitude (10-8-10-5 m/s). Kh is consistently higher near the top of the bedrock that is interpreted as the weathering front. Using a cutoff Kh of 10-10 m/s, the hydraulically significant zone extends to ∼40-53 m depth. (2) FLUTe-estimated hydraulic apertures of fractures vary over 1 order of magnitude, and at each borehole, the average hydraulic aperture by FLUTe is very close to that obtained from slug tests. Thus, slug test can be used to provide a reliable estimate of the average fracture hydraulic aperture. (3) Estimated average effective fracture porosity is 4.0 × 10-4, therefore this fractured aquifer can host significant quantity of water. (4) Natural groundwater velocity is estimated to range from 0.4 to 81.0 m/day, implying rapid pathways of fracture flow. (5) The average ambient water table position follows the boundary between saprolite and fractured bedrock. Groundwater flow at the site appears topography driven.

Bone stimulation for fracture healing: What's all the fuss?

PubMed Central

Victoria, Galkowski; Petrisor, Brad; Drew, Brian; Dick, David

2009-01-01

Approximately 10% of the 7.9 million annual fracture patients in the United States experience nonunion and/or delayed unions, which have a substantial economic and quality of life impact. A variety of devices are being marketed under the name of “bone growth stimulators.” This article provides an overview of electrical and electromagnetic stimulation, ultrasound, and extracorporeal shock waves. More research is needed for knowledge of appropriate device configurations, advancement in the field, and encouragement in the initiation of new trials, particularly large multicenter trials and randomized control trials that have standardized device and protocol methods. PMID:19838359

Establishment of a Uniform Format for Data Reporting of Structural Material Properties for Reliability Analysis

DTIC Science & Technology

1994-06-30

tip Opening Displacement (CTOD) Fracture Toughness Measurement". 48 The method has found application in the elastic-plastic fracture mechanics ( EPFM ...68 6.1 Proposed Material Property Database Format and Hierarchy .............. 68 6.2 Sample Application of the Material Property Database...the E 49.05 sub-committee. The relevant quality indicators applicable to the present program are: source of data, statistical basis of data

Foal Fractures: Osteochondral Fragmentation, Proximal Sesamoid Bone Fractures/Sesamoiditis, and Distal Phalanx Fractures.

PubMed

Reesink, Heidi L

2017-08-01

Foals are susceptible to many of the same types of fractures as adult horses, often secondary to external sources of trauma. In addition, some types of fractures are specific to foals and occur routinely in horses under 1 year of age. These foal-specific fractures may be due to the unique musculoskeletal properties of the developing animal and may present with distinct clinical signs. Treatment plans and prognoses are tailored specifically to young animals. Common fractures not affecting the long bones in foals are discussed in this article, including osteochondral fragmentation, proximal sesamoid bone fractures/sesamoiditis, and distal phalanx fractures. Copyright © 2017 Elsevier Inc. All rights reserved.

Growth Kinematics of Opening-Mode Fractures

NASA Astrophysics Data System (ADS)

Eichhubl, P.; Alzayer, Y.; Laubach, S.; Fall, A.

2014-12-01

Fracture aperture is a primary control on flow in fractured reservoirs of low matrix permeability including unconventional oil and gas reservoirs and most geothermal systems. Guided by principles of linear elastic fracture mechanics, fracture aperture is generally assumed to be a linear function of fracture length and elastic material properties. Natural opening-mode fractures with significant preserved aperture are observed in core and outcrop indicative of fracture opening strain accommodated by permanent solution-precipitation creep. Fracture opening may thus be decoupled from length growth if the material effectively weakens after initial elastic fracture growth by either non-elastic deformation processes or changes in elastic properties. To investigate the kinematics of fracture length and aperture growth, we reconstructed the opening history of three opening-mode fractures that are bridged by crack-seal quartz cement in Travis Peak Sandstone of the SFOT-1 well, East Texas. Similar crack-seal cement bridges had been interpreted to form by repeated incremental fracture opening and subsequent precipitation of quartz cement. We imaged crack-seal cement textures for bridges sampled at varying distance from the tips using scanning electron microscope cathodoluminescence, and determined the number and thickness of crack-seal cement increments as a function of position along the fracture length and height. Observed trends in increment number and thickness are consistent with an initial stage of fast fracture propagation relative to aperture growth, followed by a stage of slow propagation and pronounced aperture growth. Consistent with fluid inclusion observations indicative of fracture opening and propagation occurring over 30-40 m.y., we interpret the second phase of pronounced aperture growth to result from fracture opening strain accommodated by solution-precipitation creep and concurrent slow, possibly subcritical, fracture propagation. Similar deformation mechanisms are envisioned to govern fracture growth over shorter timescales in reactive chemical subsurface environments including CO2 reservoirs, organic-rich shales, and geothermal systems.

Application of Reservoir Flow Simulation Integrated with Geomechanics in Unconventional Tight Play

NASA Astrophysics Data System (ADS)

Lin, Menglu; Chen, Shengnan; Mbia, Ernest; Chen, Zhangxing

2018-01-01

Multistage hydraulic fracturing techniques, combined with horizontal drilling, have enabled commercial production from the vast reserves of unconventional tight formations. During hydraulic fracturing, fracturing fluid and proppants are pumped into the reservoir matrix to create the hydraulic fractures. Understanding the propagation mechanism of hydraulic fractures is essential to estimate their properties, such as half-length. In addition, natural fractures are often present in tight formations, which might be activated during the fracturing process and contribute to the post-stimulation well production rates. In this study, reservoir simulation is integrated with rock geomechanics to predict the well post-stimulation productivities. Firstly, a reservoir geological model is built based on the field data collected from the Montney formation in the Western Canadian Sedimentary Basin. The hydraulic fracturing process is then simulated through an integrated approach of fracturing fluid injection, rock geomechanics, and tensile failure criteria. In such a process, the reservoir pore pressure increases with a continuous injection of the fracturing fluid and proppants, decreasing the effective stress exerted on the rock matrix accordingly as the overburden pressure remains constant. Once the effective stress drops to a threshold value, tensile failure of the reservoir rock occurs, creating hydraulic fractures in the formation. The early production history of the stimulated well is history-matched to validate the predicted fracture geometries (e.g., half-length) generated from the fracturing simulation process. The effects of the natural fracture properties and well bottom-hole pressures on well productivity are also studied. It has been found that nearly 40% of hydraulic fractures propagate in the beginning stage (the pad step) of the fracturing schedule. In addition, well post-stimulation productivity will increase significantly if the natural fractures are propped or partially propped by the proppants. This paper provides insights on fracture propagation and can be a reference for fracturing treatments in unconventional tight reservoirs.

Dynamic osteosynthesis by modified Kuntscher nail for the treatment of tibial diaphyseal fractures.

PubMed

Gadegone, Wasudeo M; Salphale, Yogesh S

2009-04-01

We evaluated a series of diaphyseal fractures of the tibia using low-cost, Indian-made modified Kuntscher nail (Daga nail) with the provision of distal locking screw for the management of the tibial diaphyseal fractures. One hundred and fifty one consecutive patients with diaphyseal fractures of tibia with 151 fractures who were treated by Daga nail were enrolled. One of the patients who had died because of cancer, and the two patients who were lost to follow-up at 3 months were excluded from the study.Therefore data of 148 patients with one hundred and fortyeight fractures is described. One hundred twenty closed fractures, 20 open Grade I fractures, and eight open Grade II fractures as per Gustilo and Anderson classification were included in this study. One hundred fourteen men and 34 women, with a mean age of 38.4 years, were studied. The result were analysed for Surgical time, duration of hospitalisation, union time, union rate, complication rate, functional recovery and crutch walking time. The fractures were followed at least until the time of solid union. The follow-up period averaged 15 months (range, 6-26 months). Union occurred in 140 cases (94.6%). The mean time to union was 13 weeks for closed fractures,17.8 weeks for Grade I open fractures, and 21.6 weeks for Grade II open fractures. Compartment syndrome occurred in two patients. Superficial infection occurred in five cases of Grade I and II compound fractures. Three closed fractures and one case of Grade I compound fracture required bone grafting for delayed union. Two cases of Grade II compound fracture with nonunion required revision surgery and bone grafting. Twelve cases resulted in acceptable malalignment due to operative technical error. In four cases, the distal screw breakage was seen, but none of these complications interfered with fracture healing. Recovery of joint motion was essentially normal in those patients without knee or ankle injury. Unreamed distally locked dynamic tibial nailing (modified Kuntscher nail/Daga nail) can produce excellent clinical results for diaphyseal tibial fractures. It has the advantages of technical simplicity, minimal cost, user-friendly instrumentation, and a short learning curve.

A parametric study of fracture toughness of fibrous composite materials

NASA Technical Reports Server (NTRS)

Poe, C. C., Jr.

1987-01-01

Impacts to fibrous composite laminates by objects with low velocities can break fibers giving crack-like damage. The damage may not extend completely through a thick laminate. The tension strength of these damage laminates is reduced much like that of cracked metals. The fracture toughness depends on fiber and matrix properties, fiber orientations, and stacking sequence. Accordingly, a parametric study was made to determine how fiber and matrix properties and fiber orientations affect fracture toughness and notch sensitivity. The values of fracture toughness were predicted from the elastic constants of the laminate and the failing strain of the fibers using a general fracture toughness parameter developed previously. For a variety of laminates, values of fracture toughness from tests of center-cracked specimens and values of residual strength from tests of thick laminates with surface cracks were compared to the predictions to give credibility to the study. In contrast to the usual behavior of metals, it is shown that both ultimate tensile strength and fracture toughness of composites can be increased without increasing notch sensitivity.

Faulting, fracturing and in situ stress prediction in the Ahnet Basin, Algeria — a finite element approach

NASA Astrophysics Data System (ADS)

Beekman, Fred; Badsi, Madjid; van Wees, Jan-Diederik

2000-05-01

Many low-efficiency hydrocarbon reservoirs are productive largely because effective reservoir permeability is controlled by faults and natural fractures. Accurate and low-cost information on basic fault and fracture properties, orientation in particular, is critical in reducing well costs and increasing well recoveries. This paper describes how we used an advanced numerical modelling technique, the finite element method (FEM), to compute site-specific in situ stresses and rock deformation and to predict fracture attributes as a function of material properties, structural position and tectonic stress. Presented are the numerical results of two-dimensional, plane-strain end-member FEM models of a hydrocarbon-bearing fault-propagation-fold structure. Interpretation of the modelling results remains qualitative because of the intrinsic limitations of numerical modelling; however, it still allows comparisons with (the little available) geological and geophysical data. In all models, the weak mechanical strength and flow properties of a thick shale layer (the main seal) leads to a decoupling of the structural deformation of the shallower sediments from the underlying sediments and basement, and results in flexural slip across the shale layer. All models predict rock fracturing to initiate at the surface and to expand with depth under increasing horizontal tectonic compression. The stress regime for the formation of new fractures changes from compressional to shear with depth. If pre-existing fractures exist, only (sub)horizontal fractures are predicted to open, thus defining the principal orientation of effective reservoir permeability. In models that do not include a blind thrust fault in the basement, flexural amplification of the initial fold structure generates additional fracturing in the crest of the anticline controlled by the material properties of the rocks. The folding-induced fracturing expands laterally along the stratigraphic boundaries under enhanced tectonic loading. Models incorporating a blind thrust fault correctly predict the formation of secondary syn- and anti-thetic mesoscale faults in the basement and sediments of the hanging wall. Some of these faults cut reservoir and/or seal layers, and thus may influence effective reservoir permeability and affect seal integrity. The predicted faults divide the sediments across the anticline in several compartments with different stress levels and different rock failure (and proximity to failure). These numerical model outcomes can assist classic interpretation of seismic and well bore data in search of fractured and overpressured hydrocarbon reservoirs.

Treatment of displaced talar neck fractures using delayed procedures of plate fixation through dual approaches.

PubMed

Xue, Youdi; Zhang, Hui; Pei, Fuxing; Tu, Chongqi; Song, Yueming; Fang, Yue; Liu, Lei

2014-01-01

Treatment of talar neck fractures is challenging. Various surgical approaches and fixation methods have been documented. Clinical outcomes are often dissatisfying due to inadequate reduction and fixation with high rates of complications. Obtaining satisfactory clinical outcomes with minimum complications remains a hard task for orthopaedic surgeons. In the period from May 2007 to September 2010, a total of 31 cases with closed displaced talar neck fractures were treated surgically in our department. Injuries were classified according to the Hawkins classification modified by Canale and Kelly. Under general anaesthesia with sufficient muscle relaxation, urgent closed reduction was initiated once the patients were admitted; if the procedure failed, open reduction and provisional stabilisation with Kirschner wires through an anteromedial approach with tibiometatarsal external fixation were performed. When the soft tissue had recovered, definitive fixation was performed with plate and screws through dual approaches. The final follow-up examination included radiological analysis, clinical evaluation and functional outcomes which were carried out according to the Ankle-Hindfoot Scale of the American Orthopaedic Foot and Ankle Society (AOFAS), patient satisfaction and SF-36. Twenty-eight patients were followed up for an average of 25 months (range 18-50 months) after the injury. Only two patients had soft tissue complications, and recovery was satisfactory with conservative treatment. All of the fractures healed anatomically without malunion and nonunion, and the average union time was 14 weeks (range 12-24 weeks). Post-traumatic arthritis developed in ten cases, while six patients suffered from avascular necrosis of the talus. Secondary procedures included three cases of subtalar arthrodesis, one case of ankle arthrodesis and one case of total ankle replacement. The mean AOFAS hindfoot score was 78 (range 65-91). According to the SF-36, the average score of the physical component summary was 68 (range 59-81), and the average score of the mental component summary was 74 (range 63-85). Talar neck fractures are associated with a high incidence of long-term disability and complications. Urgent reduction of the fracture-dislocation and delayed plate fixation through a dual approach when the soft tissue has recovered may minimise the complications and provide good clinical outcomes.

[Repair and reconstruction for severe fracture and dislocation of ankle joint].

PubMed

Yin, Qingwei; Jiang, Yi; Xiao, Lianping; Li, Xiaodong; Fu, Jiaxin; Tian, Yonggang; Han, Liqiang; Liu, Zhi

2008-06-01

To summarize the technique and effect of the therapy for severe fracture and dislocation of ankle joint by operation. From March 2003 to February 2006, 76 cases were treated with primary open restoration and internal fixation for dislocated ankle joint fracture, with 47 males and 29 females, with the average age of 36.4 years (ranging from 18 years to 65 years). According to AO criterion, these fresh fractures were classified into 13 cases for type C3-1, 45 cases for type C3-2 and 18 cases for type C3-3. Based on the Gustilo-Anderson standard, 23 open fractures were classified into 17 cases for type II and 6 cases for type III A. The operation was delayed from 1 hours to 24 hours after the injury. All incisions healed at the first stage except 4 cases which delayed union because of simple infection by revision with ointment. A total of 72 cases were followed up, with the average time of 18.5 months (from 12 months to 35 months). The time of bone union was from 12 weeks to 24 weeks. The screws of fixation for lower tibia-fibula joint were found to be ruptured in 2 cases when further consultation was performed in the 16th and 20th week after the operation, respectively, and were broken within 1 year after the operation. These screws were taken out 12 weeks postoperative in 28 cases, while the whole internal fixations of the rest cases were taken out 1 year after the operation. The postoperative function of malleolus extended from 21.7 degrees to 26.8 degrees and flection from 38.5 degrees to 44.7 degrees. Assessed by the American Orthopaedic Foot and Ankle Society Clinical Rating Scales, 23 cases were excellent, 36 good, 13 fair, and the choiceness rate reached 81.94%. These procedures, together with reduction by twist after hospital, open and internal fixation in time, and parenchyma managed with internal fixation, are important to attain satisfactory effect for the treatment of severe fracture and dislocation of ankle joint.

Aging Periosteal Progenitor Cells have Reduced Regenerative Responsiveness to Bone Injury and to the Anabolic Actions of PTH 1-34 Treatment

PubMed Central

Yukata, Kiminori; Xie, Chao; Li, Tian-Fang; Takahata, Masahiko; Hoak, Donna; Kondabolu, Sirish; Zhang, Xinping; Awad, Hani A.; Schwarz, Edward M.; Beck, Christopher A.; Jonason, Jennifer H.; O’Keefe, Regis J.

2014-01-01

A stabilized tibia fracture model was used in young (8-week old) and aged (1-year old) mice to define the relative bone regenerative potential and the relative responsiveness of the periosteal progenitor population with aging and PTH 1-34 (PTH) systemic therapy. Bone regeneration was assessed through gene expressions, radiographic imaging, histology/histomorphometry, and biomechanical testing. Radiographs and microCT showed increased calcified callus tissue and enhanced bone healing in young compared to aged mice. A key mechanism involved reduced proliferation, expansion, and differentiation of periosteal progenitor cell populations in aged mice. The experiments showed that PTH increased calcified callus tissue and torsional strength with a greater response in young mice. Histology and quantitative histomorphometry confirmed that PTH increased callus tissue area due primarily to an increase in bone formation, since minimal changes in cartilage and mesenchyme tissue area occurred. Periosteum examined at 3, 5, and 7 days showed that PTH increased cyclin D1 expression, the total number of cells in the periosteum, and width of the periosteal regenerative tissue. Gene expression showed that aging delayed differentiation of both bone and cartilage tissues during fracture healing. PTH resulted in sustained Col10a1 expression consistent with delayed chondrocyte maturation, but otherwise minimally altered cartilage gene expression. In contrast, PTH 1-34 stimulated expression of Runx2 and Osterix, but resulted in reduced Osteocalcin. β-catenin staining was present in mesenchymal chondroprogenitors and chondrocytes in early fracture healing, but was most intense in osteoblastic cells at later times. PTH increased active β-catenin staining in the osteoblast populations of both young and aged mice, but had a lesser effect in cartilage. Altogether the findings show that reduced fracture healing in aging involves decreased proliferation and differentiation of stem cells lining the bone surface. While PTH 1-34 enhances the proliferation and expansion of the periosteal stem cell population and accelerates bone formation and fracture healing, the effects are proportionately reduced in aged mice compared to young mice. β-catenin is induced by PTH in early and late fracture healing and is a potential target of PTH 1-34 effects. PMID:24530870

Application of 3D printed customized external fixator in fracture reduction.

PubMed

Qiao, Feng; Li, Dichen; Jin, Zhongmin; Gao, Yongchang; Zhou, Tao; He, Jinlong; Cheng, Li

2015-01-01

Long bone fracture is common in traumatic osteopathic patients. Good reduction is beneficial for bone healing, preventing the complications such as delayed union, nonunion, malunion, but is hard to achieve. Repeated attempts during the surgery would increase the operation time, cause new damage to the fracture site and excessive exposure to radiation. Robotic and navigation techniques can help improve the reduction accuracy, however, the high cost and complexity of operation have limited their clinical application. We combined 3D printing with computer-assisted reduction technique to develop a customised external fixator with the function of fracture reduction. The original CT data obtained by scanning the fracture was imported to computer for reconstructing and reducing the 3D image of the fracture, based on which the external fixator (named as Q-Fixator) was designed and then fabricated by 3D printing techniques. The fracture reduction and fixation was achieved by connecting the pins inserted in the bones with the customised Q-Fixator. Experiments were conducted on three fracture models to demonstrate the reduction results. Good reduction results were obtained on all three fractured bone models, with an average rotation of 1.21°(± 0.24), angulation of 1.84°(± 0.28), and lateral displacement of 2.22 mm(± 0.62). A novel customised external fixator for long bone fracture reduction was readily developed using 3D printing technique. The customised external fixator had the advantages of easy manipulation, accurate reduction, minimally invasion and experience-independence. Future application of the customised external fixator can be extended to include the fixation function with stress adjustment and potentially optimise the fracture healing process. Copyright © 2015 Elsevier Ltd. All rights reserved.

Measurement of bone adjacent to tibial shaft fracture.

PubMed

Findlay, S C; Eastell, R; Ingle, B M

2002-12-01

Delayed union and non-union are common complications after fracture of the tibial shaft. Response of the surrounding bone as a fracture heals could be monitored using techniques currently used in the study of osteoporosis. The aims of our study were to: (1) evaluate the decrement in bone measurements made close to the fracture using dual-energy X-ray absorptiometry (DXA), quantitative ultrasound (QUS) and peripheral quantitative computed tomography (pQCT); (2) compare values for fractured versus non-fractured leg to determine the duration of decrement in bone measurements; and (3) calculate short-term precision in DXA, QUS and pQCT in order to calculate the ratio of decrement to precision (response ratio, RR) to determine the optimal test for monitoring changes after tibial fracture. The biggest decrement in bone measurements at the ipsilateral limb of 28 patients with tibial shaft fracture was observed at the pQCT tibial trabecular sites (distal = 19%, p<0.0001; proximal 5% = 21%, p<0.001; proximal 10% = 28%, p<0.001) and the ultradistal tibia/fibula measured by DXA (19%, p<0.0001). When comparing Z-scores, the magnitude of decrements at the ipsilateral limb was bigger for variables measured directly at the tibia, both proximal and distal to the fracture. The magnitude of the decrement in ultradistal tibia/fibula BMD decreased as the time since fracture increased ( r = 0.55). When response ratios are considered, pQCT measurements at the distal tibia (RR 6-8) and proximal 5% and 10% trabecular sites (RR 5 and 9 respectively) were found to be the most sensitive to change. Therefore, pQCT of the trabecular regions of either the proximal or distal tibia should prove the most sensitive measurement for monitoring changes in bone adjacent to a tibial shaft fracture.

Minimally invasive surgical technique: Percutaneous external fixation combined with titanium elastic nails for selective treatment of tibial fractures.

PubMed

Tu, Kai-Kai; Zhou, Xian-Ting; Tao, Zhou-Shan; Chen, Wei-Kai; Huang, Zheng-Liang; Sun, Tao; Zhou, Qiang; Yang, Lei

2015-12-01

Several techniques have been described to treat tibial fractures, which respectively remains defects. This article presents a novel intra- and extramedullary fixation technique: percutaneous external fixator combined with titanium elastic nails (EF-TENs system). The purpose of this study is to introduce this new minimally invasive surgical technique and selective treatment of tibial fractures, particularly in segmental fractures, diaphysis fractures accompanied with distal or proximal bone subfissure, or fractures with poor soft-tissue problems. Following ethical approval, thirty-two patients with tibial fractures were treated by the EF-TENs system between January 2010 and December 2012. The follow-up studies included clinical and radiographic examinations. All relevant outcomes were recorded during follow-up. All thirty-two patients were achieved follow-ups. According to the AO classification, 3 Type A, 9 Type B and 20 Type C fractures were included respectively. According to the Anderson-Gustilo classification, there were 5 Type Grade II, 3 Type Grade IIIA and 2 Type Grade IIIB. Among 32 patients, 8 of them were segmental fractures. 12 fractures accompanied with bone subfissure. Results showed no nonunion case, with an average time of 23.7 weeks (range, 14-32 weeks). Among them, there were 3/32 delayed union patients and 0/32 malunion case. 4/32 patients developed a pin track infection and no patient suffered deep infection. The external fixator was removed with a mean time of 16.7 weeks (range, 10-26 weeks). Moreover, only 1/32 patient suffered with the restricted ROM of ankle, none with the restricted ROM of knee. This preliminary study indicated that the EF-TENs system, as a novel intra- and extramedullary fixation technique, had substantial effects on selective treatment of tibial fractures. Copyright © 2015 Elsevier Ltd. All rights reserved.

Lattice Boltzmann simulation of CO2 reactive transport in network fractured media

NASA Astrophysics Data System (ADS)

Tian, Zhiwei; Wang, Junye

2017-08-01

Carbon dioxide (CO2) geological sequestration plays an important role in mitigating CO2 emissions for climate change. Understanding interactions of the injected CO2 with network fractures and hydrocarbons is key for optimizing and controlling CO2 geological sequestration and evaluating its risks to ground water. However, there is a well-known, difficult process in simulating the dynamic interaction of fracture-matrix, such as dynamic change of matrix porosity, unsaturated processes in rock matrix, and effect of rock mineral properties. In this paper, we develop an explicit model of the fracture-matrix interactions using multilayer bounce-back treatment as a first attempt to simulate CO2 reactive transport in network fractured media through coupling the Dardis's LBM porous model for a new interface treatment. Two kinds of typical fracture networks in porous media are simulated: straight cross network fractures and interleaving network fractures. The reaction rate and porosity distribution are illustrated and well-matched patterns are found. The species concentration distribution and evolution with time steps are also analyzed and compared with different transport properties. The results demonstrate the capability of this model to investigate the complex processes of CO2 geological injection and reactive transport in network fractured media, such as dynamic change of matrix porosity.

Phase Field Model of Hydraulic Fracturing in Poroelastic Media: Fracture Propagation, Arrest, and Branching Under Fluid Injection and Extraction

NASA Astrophysics Data System (ADS)

Santillán, David; Juanes, Ruben; Cueto-Felgueroso, Luis

2018-03-01

The simulation of fluid-driven fracture propagation in a porous medium is a major computational challenge, with applications in geosciences and engineering. The two main families of modeling approaches are those models that represent fractures as explicit discontinuities and solve the moving boundary problem and those that represent fractures as thin damaged zones, solving a continuum problem throughout. The latter family includes the so-called phase field models. Continuum approaches to fracture face validation and verification challenges, in particular grid convergence, well posedness, and physical relevance in practical scenarios. Here we propose a new quasi-static phase field formulation. The approach fully couples fluid flow in the fracture with deformation and flow in the porous medium, discretizes flow in the fracture on a lower-dimension manifold, and employs the fluid flux between the fracture and the porous solid as coupling variable. We present a numerical assessment of the model by studying the propagation of a fracture in the quarter five-spot configuration. We study the interplay between injection flow rate and rock properties and elucidate fracture propagation patterns under the leak-off toughness dominated regime as a function of injection rate, initial fracture length, and poromechanical properties. For the considered injection scenario, we show that the final fracture length depends on the injection rate, and three distinct patterns are observed. We also rationalize the system response using dimensional analysis to collapse the model results. Finally, we propose some simplifications that alleviate the computational cost of the simulations without significant loss of accuracy.

Bilateral femoral shaft fractures complicated by fat and pulmonary embolism: a case report.

PubMed

Randelli, Filippo; Capitani, Paolo; Pace, Fabrizio; Favilla, Sara; Galante, Claudio; Randelli, Pietro

2015-12-01

A 25-year-old man was admitted to our hospital because of pulmonary embolism and suspected fat embolism after sustaining bilateral femoral shaft fracture. A left arm weakness, tachycardia and sudden hemoglobin drop delayed his definitive fixation with intramedullary nailing. His clinical course was further complicated by bleeding from the pin sites of the external fixators which had initially been used to temporarily stabilize his femoral fractures (clotting disturbances). A lower leg Doppler ultrasound and a new pelvic-chest CT angiography excluded any remaining thrombus, meanwhile the embolus had broken in smaller pieces, more distally. His unfractionated heparin was revised to a Low Molecular Weight Heparin at prophylactic dose. After a 10 day period and when his condition had been improved bilateral reamed nailing was performed. Although bilateral closed femoral shaft fractures should be stabilized early, fat embolism syndrome (FES) and thromboembolic events (TEV) should always be kept in mind in these patients. Copyright © 2015 Elsevier Ltd. All rights reserved.

Toxic shock syndrome post open reduction and Kirschner wire fixation of a humeral lateral condyle fracture.

PubMed

Chan, Yuen; Selvaratnam, Veenesh; Garg, Neeraj

2015-08-11

Use of Kirschner wires (K-wires) is the most common method of fracture stabilisation in lateral condyle fracture fixation in children. We report a case of toxic shock syndrome (TSS) following an open reduction and internal fixation using K-wires for a humeral lateral condyle fracture in a 5-year-old girl. TSS is a toxin-mediated multisystem illness. It typically presents with shock and it is most often attributed to toxin-producing strains of Staphylococcus aureus and Streptococcus pyogenes. It can lead to multiorgan failure and, ultimately, death. It is important to be aware of TSS, as it can present within any setting. Patients often have non-specific symptoms and their condition can worsen rapidly. TSS postorthopaedic surgery is rare; however, due to the serious nature of this disease, it is important to promptly recognise and diagnose TSS, and to ensure appropriate treatment is started without delay. 2015 BMJ Publishing Group Ltd.

Sacral stress fracture after lumbar and lumbosacral fusion. How to manage it? A proposition based on three cases and literature review.

PubMed

Scemama, C; D'astorg, H; Guigui, P

2016-04-01

Sacral fracture after lumbosacral instrumentation could be a source of prolonged pain and a late autonomy recovery in old patients. Diagnosis remains difficult and usually delayed. No clear consensus for efficient treatment of this complication has been defined. Aim of this study was to determine how to manage them. Three patients who sustained sacral fracture after instrumented lumbosacral fusion performed for degenerative disease of the spine are discussed. History, physical examinations' findings and radiographic features are presented. Pertinent literature was analyzed. All patients complained of unspecific low back and buttock pain a few weeks after index surgery. Diagnosis was done on CT-scan. We always choose revision surgery with good functional results. Sacral stress fracture has to be reminded behind unspecific buttock or low back pain. CT-scan seems to be the best radiological test to do the diagnosis. Surgical treatment is recommended when lumbar lordosis and pelvic incidence mismatched. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Low-intensity pulsed ultrasound (LIPUS) therapy may enhance the negative effects of oxygen radicals in the acute phase of fracture.

PubMed

Zhao, Xiang; Yan, Shi-Gui

2011-02-01

Though it is well accepted that low-intensity pulsed ultrasound (LIPUS) can accelerate the healing process of a fracture with very good results, we should still pay attention to its side effects and further improve its application in detail, such as the appropriate time and point for the application. In the early phase of a bone fracture, there are millions of oxygen radicals released by neutrophils in the injured area. This article focuses on whether the increased permeability of normal cell membranes by LIPUS makes the concentration of oxygen radicals increase to such a high degree that damage occurs to healthy tissue cells. It is proposed that it may be better not to use LIPUS in the acute phase of a fracture (i.e. within 1week after injury) but instead delay its application until after any inflammatory reaction has weakened to yield better results. Copyright © 2010 Elsevier Ltd. All rights reserved.

Ankle fusion for definitive management of non-reconstructable pilon fractures.

PubMed

Bozic, Vladimir; Thordarson, David B; Hertz, Jennifer

2008-09-01

Highly comminuted pilon fractures, especially with a compromised soft tissue envelope, present a challenging treatment scenario. This study presents our results for patients managed with ankle fusion rather than ORIF. Fourteen patients with ankle joint incongruence after non-reconstructable tibia pilon fractures were treated with primary tibiotalar arthrodesis using a fixed-angle cannulated blade plate. Delayed metaphyseal unions due to bone defects were treated concurrently. The subtalar joint was preserved in all cases. Metaphyseal healing and stable arthrodesis was obtained in each case. There was one case of blade plate breakage in a patient who still achieved successful arthrodesis without reoperation. Union was achieved at an average of 15 weeks. No secondary procedures were required to obtain union. All 14 patients were ambulatory at last followup. Average followup was 39 weeks. Primary ankle arthrodesis can be achieved using a cannulated blade plate to address a non-reconstructable articular surface and metaphyseal bone defects in complex tibia pilon fractures.

Evaluation of ground-penetrating radar to detect free-phase hydrocarbons in fractured rocks - Results of numerical modeling and physical experiments

USGS Publications Warehouse

Lane, J.W.; Buursink, M.L.; Haeni, F.P.; Versteeg, R.J.

2000-01-01

The suitability of common-offset ground-penetrating radar (GPR) to detect free-phase hydrocarbons in bedrock fractures was evaluated using numerical modeling and physical experiments. The results of one- and two-dimensional numerical modeling at 100 megahertz indicate that GPR reflection amplitudes are relatively insensitive to fracture apertures ranging from 1 to 4 mm. The numerical modeling and physical experiments indicate that differences in the fluids that fill fractures significantly affect the amplitude and the polarity of electromagnetic waves reflected by subhorizontal fractures. Air-filled and hydrocarbon-filled fractures generate low-amplitude reflections that are in-phase with the transmitted pulse. Water-filled fractures create reflections with greater amplitude and opposite polarity than those reflections created by air-filled or hydrocarbon-filled fractures. The results from the numerical modeling and physical experiments demonstrate it is possible to distinguish water-filled fracture reflections from air- or hydrocarbon-filled fracture reflections, nevertheless subsurface heterogeneity, antenna coupling changes, and other sources of noise will likely make it difficult to observe these changes in GPR field data. This indicates that the routine application of common-offset GPR reflection methods for detection of hydrocarbon-filled fractures will be problematic. Ideal cases will require appropriately processed, high-quality GPR data, ground-truth information, and detailed knowledge of subsurface physical properties. Conversely, the sensitivity of GPR methods to changes in subsurface physical properties as demonstrated by the numerical and experimental results suggests the potential of using GPR methods as a monitoring tool. GPR methods may be suited for monitoring pumping and tracer tests, changes in site hydrologic conditions, and remediation activities.The suitability of common-offset ground-penetrating radar (GPR) to detect free-phase hydrocarbons in bedrock fractures was evaluated using numerical modeling and physical experiments. The results of one- and two-dimensional numerical modeling at 100 megahertz indicate that GPR reflection amplitudes are relatively insensitive to fracture apertures ranging from 1 to 4 mm. The numerical modeling and physical experiments indicate that differences in the fluids that fill fractures significantly affect the amplitude and the polarity of electromagnetic waves reflected by subhorizontal fractures. Air-filled and hydrocarbon-filled fractures generate low-amplitude reflections that are in-phase with the transmitted pulse. Water-filled fractures create reflections with greater amplitude and opposite polarity than those reflections created by air-filled or hydrocarbon-filled fractures. The results from the numerical modeling and physical experiments demonstrate it is possible to distinguish water-filled fracture reflections from air- or hydrocarbon-filled fracture reflections, nevertheless subsurface heterogeneity, antenna coupling changes, and other sources of noise will likely make it difficult to observe these changes in GPR field data. This indicates that the routine application of common-offset GPR reflection methods for detection of hydrocarbon-filled fractures will be problematic. Ideal cases will require appropriately processed, high-quality GPR data, ground-truth information, and detailed knowledge of subsurface physical properties. Conversely, the sensitivity of GPR methods to changes in subsurface physical properties as demonstrated by the numerical and experimental results suggests the potential of using GPR methods as a monitoring tool. GPR methods may be suited for monitoring pumping and tracer tests, changes in site hydrologic conditions, and remediation activities.

Modeling Staphylococcus epidermidis-Induced Non-Unions: Subclinical and Clinical Evidence in Rats

PubMed Central

Lovati, Arianna Barbara; Romanò, Carlo Luca; Bottagisio, Marta; Monti, Lorenzo; De Vecchi, Elena; Previdi, Sara; Accetta, Riccardo; Drago, Lorenzo

2016-01-01

S. epidermidis is one of the leading causes of orthopaedic infections associated with biofilm formation on implant devices. Open fractures are at risk of S. epidermidis transcutaneous contamination leading to higher non-union development compared to closed fractures. Although the role of infection in delaying fracture healing is well recognized, no in vivo models investigated the impact of subclinical low-grade infections on bone repair and non-union. We hypothesized that the non-union rate is directly related to the load of this commonly retrieved pathogen and that a low-grade contamination delays the fracture healing without clinically detectable infection. Rat femurs were osteotomized and stabilized with plates. Fractures were infected with a characterized clinical-derived methicillin-resistant S. epidermidis (103, 105, 108 colony forming units) and compared to uninfected controls. After 56 days, bone healing and osteomyelitis were clinically assessed and further evaluated by micro-CT, microbiological and histological analyses. The biofilm formation was visualized by scanning electron microscopy. The control group showed no signs of infection and a complete bone healing. The 103 group displayed variable response to infection with a 67% of altered bone healing and positive bacterial cultures, despite no clinical signs of infection present. The 105 and 108 groups showed severe signs of osteomyelitis and a non-union rate of 83–100%, respectively. The cortical bone reaction related to the periosteal elevation in the control group and the metal scattering detected by micro-CT represented limitations of this study. Our model showed that an intra-operative low-grade S. epidermidis contamination might prevent the bone healing, even in the absence of infectious signs. Our findings also pointed out a dose-dependent effect between the S. epidermidis inoculum and non-union rate. This pilot study identifies a relevant preclinical model to assess the role of subclinical infections in orthopaedic and trauma surgery and to test specifically designed diagnostic, prevention and therapeutic strategies. PMID:26796958

[Locked plating with minimally invasive percutaneous plate osteosynthesis versus intramedullary nailing of distal extra-articular tibial fracture: a retrospective study].

PubMed

Yao, Qi; Ni, Jie; Peng, Li-bin; Yu, Da-xin; Yuan, Xiao-ming

2013-12-17

To compare the efficacies of minimally invasive plate osteosynthesis (MIPPO) and interlocking intramedullary nailing (IMN) in the treatment of extra-articular fractures of distal tibia. Retrospective reviews were conducted for 126 patients with extra-articular distal tibia fractures. Treatment was either MIPPO (n = 61) or IMN (n = 65). The outcomes were assessed by comparing operating duration, time to union, the last follow-up American Orthopedic Foot and Ankle Society (AOFAS) score and complication rate. The average follow-up period was 23.7 (12-53) months. In the minimally invasive plate osteosynthesis group, there were deep infections (n = 2), superficial infections (n = 5), delayed union (n = 2), malunion (n = 2) and knee joint pain (n = 10) were observed. In addition, the average operating duration (85.9 ± 18.9 min), average time to union (17.3 ± 3.8 weeks) and average AOFAS (83.2 ± 11.9) were analyzed. In the interlocking intramedullary nailing group, there were delayed union (n = 3), malunion (n = 12) and knee joint pain (n = 22). And the average operating duration (83.3 ± 15.7 min), average time to union (16.5 ± 3.1 weeks) and average AOFAS (84.9 ± 12.0) were analyzed. No statistical significance existed in operating duration, time to union and the last follow-up AOFAS between two groups (P > 0.05). However, the rates of malformation and knee joint pain were higher in the intramedullary nail group than those in the plate group. And the difference was statistically significant (P = 0.015, P = 0.025). Both MIPPO and IMN are effective for extra-articular fractures of distal tibia. However, the former has the advantage of lowers rate of malformation and knee joint pain. Therefore a surgeon should consider the degree of injury while managing extra-articular fracture of distal tibia.

THE EFFECTS OF HYDROGEN, TRITIUM, AND HEAT TREATMENT ON THE DEFORMATION AND FRACTURE TOUGHNESS PROPERTIES OF STAINLESS STEEL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morgan, M.; Tosten, M.; Chapman, G.

2013-09-06

The deformation and fracture toughness properties of forged stainless steels pre-charged with tritium were compared to the deformation and fracture toughness properties of the same steels heat treated at 773 K or 873 K and precharged with hydrogen. Forged stainless steels pre-charged with tritium exhibit an aging effect: Fracture toughness values decrease with aging time after precharging because of the increase in concentration of helium from tritium decay. This study shows that forged stainless steels given a prior heat treatment and then pre-charged with hydrogen also exhibit an aging effect: Fracture toughness values decrease with increasing time at temperature. Amore » microstructural analysis showed that the fracture toughness reduction in the heat-treated steels was due to patches of recrystallized grains that form within the forged matrix during the heat treatment. The combination of hydrogen and the patches of recrystallized grains resulted in more deformation twinning. Heavy deformation twinning on multiple slip planes was typical for the hydrogen-charged samples; whereas, in the non-charged samples, less twinning was observed and was generally limited to one slip plane. Similar effects occur in tritium pre-charged steels, but the deformation twinning is brought on by the hardening associated with decay helium bubbles in the microstructure.« less

Graphene and its elemental analogue: A molecular dynamics view of fracture phenomenon

NASA Astrophysics Data System (ADS)

Rakib, Tawfiqur; Mojumder, Satyajit; Das, Sourav; Saha, Sourav; Motalab, Mohammad

2017-06-01

Graphene and some graphene like two dimensional materials; hexagonal boron nitride (hBN) and silicene have unique mechanical properties which severely limit the suitability of conventional theories used for common brittle and ductile materials to predict the fracture response of these materials. This study revealed the fracture response of graphene, hBN and silicene nanosheets under different tiny crack lengths by molecular dynamics (MD) simulations using LAMMPS. The useful strength of these two dimensional materials are determined by their fracture toughness. Our study shows a comparative analysis of mechanical properties among the elemental analogues of graphene and suggested that hBN can be a good substitute for graphene in terms of mechanical properties. We have also found that the pre-cracked sheets fail in brittle manner and their failure is governed by the strength of the atomic bonds at the crack tip. The MD prediction of fracture toughness shows significant difference with the fracture toughness determined by Griffth's theory of brittle failure which restricts the applicability of Griffith's criterion for these materials in case of nano-cracks. Moreover, the strengths measured in armchair and zigzag directions of nanosheets of these materials implied that the bonds in armchair direction have the stronger capability to resist crack propagation compared to zigzag direction.

Hydraulic Fracture Extending into Network in Shale: Reviewing Influence Factors and Their Mechanism

PubMed Central

Ren, Lan; Zhao, Jinzhou; Hu, Yongquan

2014-01-01

Hydraulic fracture in shale reservoir presents complex network propagation, which has essential difference with traditional plane biwing fracture at forming mechanism. Based on the research results of experiments, field fracturing practice, theory analysis, and numerical simulation, the influence factors and their mechanism of hydraulic fracture extending into network in shale have been systematically analyzed and discussed. Research results show that the fracture propagation in shale reservoir is influenced by the geological and the engineering factors, which includes rock mineral composition, rock mechanical properties, horizontal stress field, natural fractures, treating net pressure, fracturing fluid viscosity, and fracturing scale. This study has important theoretical value and practical significance to understand fracture network propagation mechanism in shale reservoir and contributes to improving the science and efficiency of shale reservoir fracturing design. PMID:25032240

Effect of tritium and decay helium on the fracture toughness properties of stainless steel weldments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morgan, M. J.; West, S.; Tosten, M. H.

2008-07-15

J-Integral fracture toughness tests were conducted on tritium-exposed-and- aged Types 304L and 21-6-9 stainless steel weldments in order to measure the combined effects of tritium and its decay product, helium-3 on the fracture toughness properties. Initially, weldments have fracture toughness values about three times higher than base-metal values. Delta-ferrite phase in the weld microstructure improved toughness provided no tritium was present in the microstructure. After a tritium-exposure-and-aging treatment that resulted in {approx}1400 atomic parts per million (appm) dissolved tritium, both weldments and base metals had their fracture toughness values reduced to about the same level. The tritium effect was greatermore » in weldments (67 % reduction vs. 37% reduction) largely because the ductile discontinuous delta-ferrite phase was embrittled by tritium and decay helium. For both base metals and weldments, fracture toughness values decreased with increasing decay helium content in the range tested (50-800 appm). (authors)« less

TRITIUM AND DECAY HELIUM EFFECTS ON THE FRACTURE TOUGHNESS PROPERTIES OF STAINLESS STEEL WELDMENTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morgan, M; Scott West, S; Michael Tosten, M

2007-08-31

J-Integral fracture toughness tests were conducted on tritium-exposed-and-aged Types 304L and 21-6-9 stainless steel weldments in order to measure the combined effects of tritium and its decay product, helium-3 on the fracture toughness properties. Initially, weldments have fracture toughness values about three times higher than base-metal values. Delta-ferrite phase in the weld microstructure improved toughness provided no tritium was present in the microstructure. After a tritium-exposure-and-aging treatment that resulted in {approx}1400 atomic parts per million (appm) dissolved tritium, both weldments and base metals had their fracture toughness values reduced to about the same level. The tritium effect was greater inmore » weldments (67 % reduction vs. 37% reduction) largely because the ductile discontinuous delta-ferrite interfaces were embrittled by tritium and decay helium. Fracture toughness values decreased for both base metals and weldments with increasing decay helium content in the range tested (50-200 appm).« less

Numerical modeling of thermal conductive heating in fractured bedrock.

PubMed

Baston, Daniel P; Falta, Ronald W; Kueper, Bernard H

2010-01-01

Numerical modeling was employed to study the performance of thermal conductive heating (TCH) in fractured shale under a variety of hydrogeological conditions. Model results show that groundwater flow in fractures does not significantly affect the minimum treatment zone temperature, except near the beginning of heating or when groundwater influx is high. However, fracture and rock matrix properties can significantly influence the time necessary to remove all liquid water (i.e., reach superheated steam conditions) in the treatment area. Low matrix permeability, high matrix porosity, and wide fracture spacing can contribute to boiling point elevation in the rock matrix. Consequently, knowledge of these properties is important for the estimation of treatment times. Because of the variability in boiling point throughout a fractured rock treatment zone and the absence of a well-defined constant temperature boiling plateau in the rock matrix, it may be difficult to monitor the progress of thermal treatment using temperature measurements alone. Copyright © 2010 The Author(s). Journal compilation © 2010 National Ground Water Association.

Mechanical Properties and Microstructure of Biomorphic Silicon Carbide Ceramics Fabricated from Wood Precursors

NASA Technical Reports Server (NTRS)

Singh, Mrityunjay; Salem, J. A.; Gray, Hugh R. (Technical Monitor)

2002-01-01

Silicon carbide based, environment friendly, biomorphic ceramics have been fabricated by the pyrolysis and infiltration of natural wood (maple and mahogany) precursors. This technology provides an eco-friendly route to advanced ceramic materials. These biomorphic silicon carbide ceramics have tailorable properties and behave like silicon carbide based materials manufactured by conventional approaches. The elastic moduli and fracture toughness of biomorphic ceramics strongly depend on the properties of starting wood preforms and the degree of molten silicon infiltration. Mechanical properties of silicon carbide ceramics fabricated from maple wood precursors indicate the flexural strengths of 3441+/-58 MPa at room temperature and 230136 MPa at 1350C. Room temperature fracture toughness of the maple based material is 2.6 +/- 0.2 MPa(square root of)m while the mahogany precursor derived ceramics show a fracture toughness of 2.0 +/- 0.2 Mpa(square root of)m. The fracture toughness and the strength increase as the density of final material increases. Fractographic characterization indicates the failure origins to be pores and chipped pockets of silicon.

Effect of autoclave postpolymerization treatments on the fracture toughness of autopolymerizing dental acrylic resins.

PubMed

Durkan, Rukiye; Gürbüz, Ayhan; Yilmaz, Burak; Özel, M Birol; Bağış, Bora

2012-06-26

Microwave and water bath postpolymerization have been suggested as methods to improve the mechanical properties of heat and autopolymerizing acrylic resins. However, the effects of autoclave heating on the fracture properties of autopolymerizing acrylic resins have not been investigated. The aim of this study was to assess the effectiveness of various autoclave postpolymerization methods on the fracture properties of 3 different autopolymerizing acrylic resins. Forty-two specimens of 3 different autopolymerizing acrylic resins (Orthocryl, Paladent RR and Futurajet) were fabricated (40x8x4mm), and each group was further divided into 6 subgroups (n=7). Control group specimens remained as processed (Group 1). The first test group was postpolymerized in a cassette autoclave at 135°C for 6 minutes and the other groups were postpolymerized in a conventional autoclave at 130°C using different time settings (5, 10, 20 or 30 minutes). Fracture toughness was then measured with a three-point bending test. Data were analyzed by ANOVA followed by the Duncan test (α=0.05). The fracture toughness of Orthocryl and Paladent-RR acrylic resins significantly increased following conventional autoclave postpolymerization at 130°C for 10 minutes (P<.05). However, the fracture toughness of autoclave postpolymerized Futurajet was not significantly different than its control specimens (P<.05). The fracture toughness of Futurajet was significantly less than Paladent RR and Orthocryl specimens when autoclaved at 130°C for 10 minutes. Within the limitations of this study, it can be suggested that autoclave postpolymerization is an effective method for increasing the fracture toughness of tested autoploymerized acrylic resins.

Reamed versus unreamed intramedullary nailing for the treatment of femoral fractures

PubMed Central

Li, A-Bing; Zhang, Wei-Jiang; Guo, Wei-Jun; Wang, Xin-Hua; Jin, Hai-Ming; Zhao, You-Ming

2016-01-01

Abstract Background and objective: Intramedullary nailing is commonly used for treating femoral shaft fractures, one of the most common long bone fractures in adults. The reamed intramedullary nail is considered the standard implant for femoral fractures. This meta-analysis was performed to verify the superiority of reamed intramedullary nailing over unreamed intramedullary nailing in fractures of the femoral shaft in adults. Subgroup analysis of implant failure and secondary procedure was also performed. Methods: Electronic literature databases were used to identify relevant publications and included MEDLINE (Ovid interface), EMBASE (Ovid interface), and the Cochrane Central Register of Controlled Trials (CENTRAL; Wiley Online Library). The versions available on January 30, 2016, were utilized. Only human studies, which were designed as randomized controlled clinical trials, were included. Two authors independently evaluated the quality of original research publications and extracted data from the studies that met the criteria. Results: Around 8 randomized controlled trials involving 1078 patients were included. Reamed intramedullary nailing was associated with shorter time to consolidation of the fracture (SMD = –0.62, 95% CI = –0.89 to –0.35, P < 0.00001), lower secondary procedure rate (OR = 0.25, 95% CI 0.10–0.62, P = 0.003), lower nonunion rate (OR = 0.14, 95% CI = 0.05–0.40, P < 0.01), and lower delayed-union rate (OR = 0.19, 95% CI = 0.07–0.49, P < 0.01) compared to unreamed intramedullary nailing. The 2 groups showed no significant differences in risk of implant failure (OR = 0.50, 95% CI 0.14–1.74, P = 0.27), mortality risk (OR = 0.94, 95% CI 0.19–4.68, P = 0.94), risk of acute respiratory distress syndrome (ARDS; OR = 1.55, 95% CI 0.36–6.57, P = 0.55), or blood loss (SMD = 0.57, 95% CI = –0.22 to 1.36, P = 0.15). Conclusion: Reamed intramedullary nailing is correlated with shorter time to union and lower rates of delayed-union, nonunion, and reoperation. Reamed intramedullary nailing did not increase blood loss or the rates of ARDS, implant failure, and mortality compared to unreamed intramedullary nailing. Therefore, the treatment of femoral fractures using reamed intramedullary nailing is recommended. PMID:27442651

The effect of the Tscherne injury pattern on the outcome of operatively treated Lisfranc fracture dislocations.

PubMed

Demirkale, Ismail; Tecimel, Osman; Celik, Ismail; Kilicarslan, Kasim; Ocguder, Ali; Dogan, Metin

2013-09-01

Lisfranc fracture dislocations cause severe tarso-metatarsal malalignment. The research question of this study was to evaluate the severity of the soft tissue injury on the final clinical outcome and compare that with the effect of various determinants on the disability in daily living activities after open reduction and internal fixation of a Lisfranc injury. This study consisted of a retrospective analysis of patients with Lisfranc fracture dislocations who were treated by open reduction and internal fixation beween 2004 and 2009. Evaluation focused mainly on the severity of the soft tissue injury, age, fracture classification, time to operation, posttraumatic osteoarthritis, and the results were compared with American Foot and Ankle Society (AOFAS) scores, and Foot and Ankle Disability Index (FADI). Eight patients had Tscherne Grade 1, 13 had Grade 2, and 11 had Grade 3 soft tissue injuries. Myerson classification revealed 11 type A, 8 type B and 13 type C fractures. Six patients' operations were delayed beyond 8h. Of the 38 patients treated in the study period, 32 patients (11 female, 21 male; <30 y-old: 14, >30 y-old: 18) were available for complete follow-up (average, 55.5 months). The comparison of treatment results revealed that those patients with high grade soft tissue injuries had lower AOFAS and FADI scores (43.8±15.9, 53.7±9.4, respectively) when compared to Tscherne Grade 1 injuries (82.8±6.1, 109±13.9, respectively) (p<0.001). The overall negative impact of the severity of soft tissue injury on functional outcomes had similar significance with regard to post-traumatic osteoarthritis, and fracture type. There was also a statistically significant difference between outcome measures and post-reduction quality (p=0.002). Patient age (p=0.9) and delayed surgery (p=0.5) had no statistically significant effect on the final outcome. Satisfactory results can be achieved with open reduction for Lisfranc injuries. However, despite this treatment, both the severity of the soft tissue injury and non-anatomic reduction are negative prognostic factors in the treatment of Lisfranc fracture dislocations. Copyright © 2013 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

The hip fracture incidence curve is shifting to the right

PubMed Central

2009-01-01

Background The number of hip fractures has doubled in the last 30–40 years in many countries. Age-adjusted incidence has been reported to be decreasing in Europe and North America, but is there a decreasing trend in all age groups? Patients and methods This population-based study included all hip-fracture patients over 50 years of age (a total of 2,919 individuals, 31% of whom were men) admitted to Umeå University Hospital, Sweden, from 1993 through 2005. Results The incidence of hip fracture declined between the periods 1993–1996 and 2001–2005: from 706 to 625 hip fractures per 105 women and from 390 to 317 hip fractures per 105 men. However, there was a 114% increase in the number of fractures in women aged 90 or older (12 and 25 hip fractures/year, respectively, in the two time periods). For the period 2001–05, women ≥ 90 years of age accounted for almost the same numbers of hip fractures as women aged 75–79 (27 fractures/year). The rate increased during this period, from 2,700 per 105 women to 3,900 per 105 women > 90 years. In men there were declining trends for both relative and absolute numbers. Interpretation Although age-adjusted incidence declined in the population > 50 years of age, absolute fracture rate and incidence increased in the very old. Women over 90 now have the same absolute number of hip fractures every year as women aged 75–79 years. There was a right-shift in hip fracture distribution towards the oldest old, probably due to an increased number of octo/nonagenarians, a new population of particularly frail old people that hardly existed earlier. Better health among septuagenarians may also have delayed the age at which fractures occurred. This changing pattern will strain orthopedic and geriatric resources even more. PMID:19916682

Mandibular Fracture Patterns at a Medical Center in Central Taiwan: A 3-Year Epidemiological Review.

PubMed

Lin, Fu-Yu; Wu, Chao-I; Cheng, Hsu-Tang

2017-12-01

Mandibular fractures constitute a major portion of maxillofacial trauma and may lead to considerable functional and aesthetic sequelae if treatment is inadequate or delayed. An epidemiology study on mandibular fractures may guide the preventive efforts of the Taiwan public health care system. Therefore, a retrospective review was conducted at a medical center in central Taiwan to evaluate the current mandibular fracture epidemiology.The medical records and digitized radiographs of 198 patients who received treatment for mandibular fractures during a 3-year period (from October 2010 to September 2013) at a medical center in central Taiwan were reviewed to obtain demographic and injury data.The average age was 29.4 years (3-82 years). Patients aged 21 to 30 years sustained the most mandibular fractures (62 patients, 31.3%). The overall sex distribution (male to female) ratio was 1.8. Motor-vehicle accidents (MVAs) were the most common mechanism of injury (162 patients, 82%), and scooter and motorcycle riders wearing partial-coverage helmets constituted the majority of patients. A chart review identified 198 patients with 335 mandibular fractures; 113 patients (57.1%) had multiple mandibular fractures. The most common fracture sites were the symphysis and parasymphysis regions (38.9%), followed by the condyle (26.0%), angle (14.3%), body (14.3%), and ramus (6.6%).MVAs are the major cause of mandibular fractures in central Taiwan, and patients aged <30 years sustained the most mandibular fractures. Compared with previous studies, the present study has a higher percentage of women with mandibular fractures. In addition, inadequate mandibular protection by partial-coverage helmets may be a major reason for mandibular fractures most commonly localized in the symphysis and parasymphysis regions. The incidence and causes of mandibular fractures may reflect the trauma patterns within the community, thus facilitating the development of a preventive strategy for the socioeconomic and environmental background of central Taiwan. Copyright © 2017 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.

Degraded and osteogenic properties of coated magnesium alloy AZ31; an experimental study.

PubMed

Zhuang, Jinpeng; Jing, Yongbin; Wang, Yaming; Zhang, Jinghuai; Xie, Huanxin; Yan, Jinglong

2016-03-14

Degraded and osteogenic property of coated magnesium alloy was evaluated for the fracture fixation in rabbits. Magnesium alloy AZ31 with a different coating thickness by microarc oxidation was used, and the bilateral radial fracture model was created by the bite bone clamp. Thirty-six New Zealand white rabbits in weight of 2.5~3.0 kg were randomly divided into A, B, and C groups at four time points and other 3 rabbits as the control group without magnesium alloy. Coated magnesium alloy AZ31 was implanted on the fracture and fixed with silk thread. Indexes such as general observation, histology, X-ray, hematology, and mechanical properties were observed and detected at 2nd, 4th, 8th, and 12th week after implantation. Fracture in each rabbit was healed at 12th week after implantation. Among the three groups, the best results of general observation, histology, and X-ray appeared in A group without coating. However, A group showed the worst results from the perspective of mechanical properties about tensile strength and flexural strength, which failed to reach that of the natural bone at the 12th week. Comprehensive results displayed that C group with 20-μm coating was better than others in mechanical properties, while there is no difference between B and C groups in hematology. Degradation rate is inversely proportional to the coating thickness. And magnesium alloy with a 20-μm coating is more suitable for the fracture fixation.

Dynamic seismic signatures of saturated porous rocks containing two orthogonal sets of fractures: theory versus numerical simulations

NASA Astrophysics Data System (ADS)

Guo, Junxin; Rubino, J. Germán; Glubokovskikh, Stanislav; Gurevich, Boris

2018-05-01

The dispersion and attenuation of seismic waves are potentially important attributes for the non-invasive detection and characterization of fracture networks. A primary mechanism for these phenomena is wave-induced fluid flow (WIFF), which can take place between fractures and their embedding background (FB-WIFF), as well as within connected fractures (FF-WIFF). In this work, we propose a theoretical approach to quantify seismic dispersion and attenuation related to these two manifestations of WIFF in saturated porous rocks permeated by two orthogonal sets of fractures. The methodology is based on existing theoretical models for rocks with aligned fractures, and we consider three types of fracture geometries, namely, periodic planar fractures, randomly spaced planar fractures and penny-shaped cracks. Synthetic 2-D rock samples with different degrees of fracture intersections are then explored by considering both the proposed theoretical approach and a numerical upscaling procedure that provides the effective seismic properties of generic heterogeneous porous media. The results show that the theoretical predictions are in overall good agreement with the numerical simulations, in terms of both the stiffness coefficients and the anisotropic properties. For the seismic dispersion and attenuation caused by FB-WIFF, the theoretical model for penny-shaped cracks matches the numerical simulations best, whereas for representing the effects due to FF-WIFF the periodic planar fractures model turns out to be the most suitable one. The proposed theoretical approach is easy to apply and is applicable not only to 2-D but also to 3-D fracture systems. Hence, it has the potential to constitute a useful framework for the seismic characterization of fractured reservoirs, especially in the presence of intersecting fractures.

A Numerical Study of Factors Affecting Fracture-Fluid Cleanup and Produced Gas/Water in Marcellus Shale: Part II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seales, Maxian B.; Dilmore, Robert; Ertekin, Turgay

Horizontal wells combined with successful multi-stage hydraulic fracture treatments are currently the most established method for effectively stimulating and enabling economic development of gas bearing organic-rich shale formations. Fracture cleanup in the Stimulated Reservoir Volume (SRV) is critical to stimulation effectiveness and long-term well performance. However, fluid cleanup is often hampered by formation damage, and post-fracture well performance frequently falls below expectations. A systematic study of the factors that hinder fracture fluid cleanup in shale formations can help optimize fracture treatments and better quantify long term volumes of produced water and gas. Fracture fluid cleanup is a complex process influencedmore » by multi-phase flow through porous media (relative permeability hysteresis, capillary pressure etc.), reservoir rock and fluid properties, fracture fluid properties, proppant placement, fracture treatment parameters, and subsequent flowback and field operations. Changing SRV and fracture conductivity as production progresses further adds to the complexity of this problem. Numerical simulation is the best, and most practical approach to investigate such a complicated blend of mechanisms, parameters, their interactions, and subsequent impact on fracture fluid cleanup and well deliverability. In this paper, a 3-dimensional, 2-phase, dual-porosity model was used to investigate the impact of multiphase flow, proppant crushing, proppant diagenesis, shut-in time, reservoir rock compaction, gas slippage, and gas desorption on fracture fluid cleanup, and well performance in Marcellus shale. The research findings have shed light on the factors that substantially constrains efficient fracture fluid cleanup in gas shales, and provided guidelines for improved fracture treatment designs and water management.« less

Modelling deformation and fracture of Gilsocarbon graphite subject to service environments

NASA Astrophysics Data System (ADS)

Šavija, Branko; Smith, Gillian E.; Heard, Peter J.; Sarakinou, Eleni; Darnbrough, James E.; Hallam, Keith R.; Schlangen, Erik; Flewitt, Peter E. J.

2018-02-01

Commercial graphites are used for a wide range of applications. For example, Gilsocarbon graphite is used within the reactor core of advanced gas-cooled reactors (AGRs, UK) as a moderator. In service, the mechanical properties of the graphite are changed as a result of neutron irradiation induced defects and porosity arising from radiolytic oxidation. In this paper, we discuss measurements undertaken of mechanical properties at the micro-length-scale for virgin and irradiated graphite. These data provide the necessary inputs to an experimentally-informed model that predicts the deformation and fracture properties of Gilsocarbon graphite at the centimetre length-scale, which is commensurate with laboratory test specimen data. The model predictions provide an improved understanding of how the mechanical properties and fracture characteristics of this type of graphite change as a result of exposure to the reactor service environment.

Which is guilty in self-induced penile fractures: marital status, culture or geographic region? A case series and literature review.

PubMed

Al Ansari, A; Talib, R A; Shamsodini, A; Hayati, A; Canguven, O; Al Naimi, A

2013-01-01

Penile fracture is a well-recognized and relatively uncommon clinical entity. It was previously reported that the incidence of penile fracture varies according to various geographic regions. In order to determine whether marital status or culture other than geographic region is involved in the etiology of penile fracture in our country, the charts of 122 men diagnosed with penile fracture were retrospectively reviewed. Detailed history including cause, symptoms, country of origin and a single-question self-report of erectile dysfunction was used for all cases. Diagnosis of our cases was mainly based on history and physical examination and ultrasonography. Immediate or delayed surgical repair of penile fracture included a degloving circumferential, and an additional direct incision, if the site of the tear could not be reached via degloving, was performed. The patients were evaluated after 1 week and 1, 3, and 6 months follow-up by penile examination, recording complications, and with a single-question self-report questionnaire after 3 and 6 months. The most common cause of penile fracture was manual bending of the erected penis in 66 out of 122 (54.1%) of our study patients. In our study, we believe that the prime causes of bending the penis are single status and culture, which are influencing factors irrespective of the geographic distribution.

RECONSIDERATIONS REGARDING TIME OF FRACTURE HEALING IN PYCNODYSOSTOSIS

PubMed Central

Rabelo, Flávio Dorcilo; do Prado, Carlos Henrique Ribeiro; Rabelo, Flávio Leão; Martins, Letícia

2015-01-01

Objective: To discuss what has been described so far in the literature regarding the time taken for fracture consolidation in pycnodysostosis. Materials and Methods: Thirteen new cases were studied, as available from the medical records and radiographic examinations, thus encompassing a total of 44 fractures in patients evaluated between November 1970 and August 2004 at the Orthopedics Hospital, Goiânia. Field research, simultaneous clinical monitoring for new fractures in two patients and retrospective evaluation of medical records were undertaken. The purpose was to determine the total number of fractures in each patient and to determine which of these were viable for this study. The patient group was composed of three women and two men of mean age 51.4 years. The tibia was the bone most affected, followed by the femur. Fractures for which the follow-up was done at another clinic were excluded. Results: Out of the 12 fractures that were considered fully suitable for the study, nine occurred in femurs (six in the left femur and three in the right femur); one in the right tibia; one in the right clavicle; and one in the left ulna. Among these 12 fractures, eight developed pseudarthrosis after an average of 29.25 months; three consolidated well after an average of 5.83 months; and one evolved with delayed consolidation in just 2 months. Conclusion: In combination with genetic and micromorphological evaluations, further studies are awaited for reconfirmation of the diagnosis of such a rare clinical entity. PMID:27026972

Numerical Simulation of Callus Healing for Optimization of Fracture Fixation Stiffness

PubMed Central

Steiner, Malte; Claes, Lutz; Ignatius, Anita; Simon, Ulrich; Wehner, Tim

2014-01-01

The stiffness of fracture fixation devices together with musculoskeletal loading defines the mechanical environment within a long bone fracture, and can be quantified by the interfragmentary movement. In vivo results suggested that this can have acceleratory or inhibitory influences, depending on direction and magnitude of motion, indicating that some complications in fracture treatment could be avoided by optimizing the fixation stiffness. However, general statements are difficult to make due to the limited number of experimental findings. The aim of this study was therefore to numerically investigate healing outcomes under various combinations of shear and axial fixation stiffness, and to detect the optimal configuration. A calibrated and established numerical model was used to predict fracture healing for numerous combinations of axial and shear fixation stiffness under physiological, superimposed, axial compressive and translational shear loading in sheep. Characteristic maps of healing outcome versus fixation stiffness (axial and shear) were created. The results suggest that delayed healing of 3 mm transversal fracture gaps will occur for highly flexible or very rigid axial fixation, which was corroborated by in vivo findings. The optimal fixation stiffness for ovine long bone fractures was predicted to be 1000–2500 N/mm in the axial and >300 N/mm in the shear direction. In summary, an optimized, moderate axial stiffness together with certain shear stiffness enhances fracture healing processes. The negative influence of one improper stiffness can be compensated by adjustment of the stiffness in the other direction. PMID:24991809

The interaction of projectiles with tissues and the management of ballistic fractures.

PubMed

Clasper, J

2001-02-01

Wounds to the limbs are the commonest injuries seen during armed conflict and injury results from the transfer of energy from the missile to the tissues. There are a number of factors that determine the transfer of energy, and thus the extent of wounding. These include the velocity of the missile, its shape and stability, and the tissue through which the missile passes. Many of the wounds involve bone, and because of the interaction of missiles with bone, significant fractures can occur. In many previous conflicts amputation was considered the treatment of choice for many limb injuries, but with recent advances in the management of severe open fractures, many of these limbs are now salvageable. Whilst the basic principles of the initial débridement remain unchanged, techniques of fracture stabilisation and definitive soft tissue cover have changed, and it is necessary to consider these in relation to military fractures. Definitive soft tissue closure can be safely delayed until evacuation further down the medical chain, but stabilisation of the fracture must be considered at the time of initial surgery. Many of the advances in fracture management may be unsuitable for use in a military environment due to logistical constraints. In addition it is likely that wound infection will be more common with military injuries, and this will influence the treatment. This paper considers the interaction of missiles with soft tissue and bone, and discusses possible methods of fracture stabilisation in the military environment.

Numerical simulation of callus healing for optimization of fracture fixation stiffness.

PubMed

Steiner, Malte; Claes, Lutz; Ignatius, Anita; Simon, Ulrich; Wehner, Tim

2014-01-01

The stiffness of fracture fixation devices together with musculoskeletal loading defines the mechanical environment within a long bone fracture, and can be quantified by the interfragmentary movement. In vivo results suggested that this can have acceleratory or inhibitory influences, depending on direction and magnitude of motion, indicating that some complications in fracture treatment could be avoided by optimizing the fixation stiffness. However, general statements are difficult to make due to the limited number of experimental findings. The aim of this study was therefore to numerically investigate healing outcomes under various combinations of shear and axial fixation stiffness, and to detect the optimal configuration. A calibrated and established numerical model was used to predict fracture healing for numerous combinations of axial and shear fixation stiffness under physiological, superimposed, axial compressive and translational shear loading in sheep. Characteristic maps of healing outcome versus fixation stiffness (axial and shear) were created. The results suggest that delayed healing of 3 mm transversal fracture gaps will occur for highly flexible or very rigid axial fixation, which was corroborated by in vivo findings. The optimal fixation stiffness for ovine long bone fractures was predicted to be 1000-2500 N/mm in the axial and >300 N/mm in the shear direction. In summary, an optimized, moderate axial stiffness together with certain shear stiffness enhances fracture healing processes. The negative influence of one improper stiffness can be compensated by adjustment of the stiffness in the other direction.

A small interfering RNA targeting Lnk accelerates bone fracture healing with early neovascularization.

PubMed

Kawakami, Yohei; Ii, Masaaki; Matsumoto, Tomoyuki; Kawamoto, Atsuhiko; Kuroda, Ryosuke; Akimaru, Hiroshi; Mifune, Yutaka; Shoji, Taro; Fukui, Tomoaki; Asahi, Michio; Kurosaka, Masahiro; Asahara, Takayuki

2013-09-01

Lnk, an intracellular adapter protein, is expressed in hematopoietic cell lineages, which has recently been proved as an essential inhibitory signaling molecule for stem cell self-renewal in the stem cell factor-c-Kit signaling pathway with enhanced hematopoietic and osteogenic reconstitution in Lnk-deficient mice. Moreover, the therapeutic potential of hematopoietic stem/endothelial progenitor cells (EPCs) for fracture healing has been demonstrated with mechanistic insight into vasculogenesis/angiogenesis and osteogenesis enhancement in the fracture sites. We report here, Lnk siRNA-transfected endothelial commitment of c-kit+/Sca-1+/lineage- subpopulations of bone marrow cells have high EPC colony-forming capacity exhibiting endothelial markers, VE-Cad, VEGF and Ang-1. Lnk siRNA-transfected osteoblasts also show highly osteoblastic capacity. In vivo, locally transfected Lnk siRNA could successfully downregulate the expression of Lnk at the fracture site up to 1 week, and radiological and histological examination showed extremely accelerated fracture healing in Lnk siRNA-transfected mice. Moreover, Lnk siRNA-transfected mice exhibited sufficient therapeutic outcomes with intrinstic enhancement of angiogenesis and osteogenesis, specifically, the mice demonstrated better blood flow recovery in the sites of fracture. In our series of experiments, we clarified that a negatively regulated Lnk system contributed to a favorable circumstance for fracture healing by enhancing vasculogenesis/angiogenesis and osteogenesis. These findings suggest that downregulation of Lnk system may have the clinical potential for faster fracture healing, which contributes to the reduction of delayed unions or non-unions.

Direct transplantation of native pericytes from adipose tissue: A new perspective to stimulate healing in critical size bone defects.

PubMed

König, Matthias A; Canepa, Daisy D; Cadosch, Dieter; Casanova, Elisa; Heinzelmann, Michael; Rittirsch, Daniel; Plecko, Michael; Hemmi, Sonja; Simmen, Hans-Peter; Cinelli, Paolo; Wanner, Guido A

2016-01-01

Fractures with a critical size bone defect (e.g., open fracture with segmental bone loss) are associated with high rates of delayed union and non-union. The prevention and treatment of these complications remain a serious issue in trauma and orthopaedic surgery. Autologous cancellous bone grafting is a well-established and widely used technique. However, it has drawbacks related to availability, increased morbidity and insufficient efficacy. Mesenchymal stromal cells can potentially be used to improve fracture healing. In particular, human fat tissue has been identified as a good source of multilineage adipose-derived stem cells, which can be differentiated into osteoblasts. The main issue is that mesenchymal stromal cells are a heterogeneous population of progenitors and lineage-committed cells harboring a broad range of regenerative properties. This heterogeneity is also mirrored in the differentiation potential of these cells. In the present study, we sought to test the possibility to enrich defined subpopulations of stem/progenitor cells for direct therapeutic application without requiring an in vitro expansion. We enriched a CD146+NG2+CD45- population of pericytes from freshly isolated stromal vascular fraction from mouse fat tissue and tested their osteogenic differentiation capacity in vitro and in vivo in a mouse model for critical size bone injury. Our results confirm the ability of enriched CD146+NG2+CD45- cells to efficiently generate osteoblasts in vitro, to colonize cancellous bone scaffolds and to successfully contribute to regeneration of large bone defects in vivo. This study represents proof of principle for the direct use of enriched populations of cells with stem/progenitor identity for therapeutic applications. Copyright © 2015 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Experimental stimulation of bone healing with teriparatide: histomorphometric and microhardness analysis in a mouse model of closed fracture.

PubMed

Mognetti, Barbara; Marino, Silvia; Barberis, Alessandro; Martin, Anne-Sophie Bravo; Bala, Yohann; Di Carlo, Francesco; Boivin, Georges; Barbos, Michele Portigliatti

2011-08-01

Fracture consolidation is a crucial goal to achieve as early as possible, but pharmacological stimulation has been neglected so far. Teriparatide has been considered for this purpose for its anabolic properties. We set up a murine model of closed tibial fracture on which different doses of teriparatide were tested. Closed fracture treatment avoids any bias introduced by surgical manipulations. Teriparatide's effect on callus formation was monitored during the first 4 weeks from fracture. Callus evolution was determined by histomorphometric and microhardness assessment. Daily administration of 40 μg/kg of teriparatide accelerated callus mineralization from day 9 onward without significant increase of sizes, and at day 15 the microhardness properties of treated callus were similar to those of bone tissue. Teriparatide considerably improved callus consolidation in the very early phases of bone healing.

A methodology for using borehole temperature-depth profiles under ambient, single and cross-borehole pumping conditions to estimate fracture hydraulic properties

NASA Astrophysics Data System (ADS)

Klepikova, Maria V.; Le Borgne, Tanguy; Bour, Olivier; Davy, Philippe

2011-09-01

SummaryTemperature profiles in the subsurface are known to be sensitive to groundwater flow. Here we show that they are also strongly related to vertical flow in the boreholes themselves. Based on a numerical model of flow and heat transfer at the borehole scale, we propose a method to invert temperature measurements to derive borehole flow velocities. This method is applied to an experimental site in fractured crystalline rocks. Vertical flow velocities deduced from the inversion of temperature measurements are compared with direct heat-pulse flowmeter measurements showing a good agreement over two orders of magnitudes. Applying this methodology under ambient, single and cross-borehole pumping conditions allows us to estimate fracture hydraulic head and local transmissivity, as well as inter-borehole fracture connectivity. Thus, these results provide new insights on how to include temperature profiles in inverse problems for estimating hydraulic fracture properties.

3D convection in a fractured porous medium : influence of fracture network parameters and comparison to homogeneous approach.

NASA Astrophysics Data System (ADS)

Mezon, Cécile; Mourzenko, Valeri; François Thovert, Jean; Antoine, Raphael; Fontaine, Fabrice; Finizola, Anthony; Adler, Pierre Michel

2016-04-01

In the crust, fractures/faults can provide preferential pathways for fluid flow or act as barriers preventing the flow across these structures. In hydrothermal systems (usually found in fractured rock masses), these discontinuities may play a critical role at various scales, controlling fluid flows and heat transfer. The thermal convection is numerically computed in 3D fluid satured isotropically fractured porous media. Fractures are inserted as 2D convex polygons, which are randomly located. The fluid is assumed to satisfy 2D and 3D Darcy's law in the fractures and in the porous medium, respectively; exchanges take place between these two structures. First, checks were performed on an unfractured porous medium and the convection cells do start for the theoretical value of Ra, namely 4pi². 2D convection was verified up to Ra=800. Second, all fractured simulations were made for Rayleigh numbers (Ra) < 150, cubic boxes and closed-top conditions. The influence of parameters such as fracture aperture (or fracture transmissivity) and fracture density on the heat released by the whole system is studied. Then, the effective permeability of each fractured system is calculated. This last calculation enables the comparison between all fractured models and models of homogeneous medium with the same macroscopic properties. First, the heat increase released by the system as a function of fracture transmissivity and fracture density is determined. Second, results show that the effective approach is valid for low Ra (< 70), and that the mismatch between the full calculations and the effective medium approach for Ra higher than 70 depends on the fracture density in a crucial way. Third, the study also reveals that equivalent properties could be deduced from these computations in order to estimate the heat released by a fractured system from an homogeneous approach.