Science.gov

Sample records for calcaneal stress fractures

  1. Diabetic calcaneal fractures.

    PubMed

    Sagray, Bryan A; Stapleton, John J; Zgonis, Thomas

    2013-01-01

    Calcaneal fractures among the diabetic population are severe and complex injuries that warrant careful evaluation in an effort to carry out adequate conservative or surgical management. The complication rates associated with diabetic fracture management are increased and may include poor wound healing, deep infection, malunion, and Charcot neuroarthropathy, each of which can pose a risk for limb loss. The significant surgery-associated morbidity accompanying diabetic calcaneal fractures has led to improved methods of calcaneal fracture management. This article reviews the overall management of diabetic calcaneal fractures, complications, and outcomes. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Calcaneal apophyseal avulsion fracture.

    PubMed

    Imai, Yuuki; Kitano, Toshio; Nakagawa, Keisuke; Takaoka, Kunio

    2007-07-01

    Isolated fracture of the calcaneal apophysis is a rare injury in children and adolescents. In this study, we report on a case of a displaced calcaneal apophyseal avulsion fracture in a child treated with open reduction and internal fixation, as well as a review of the literature. A 9-year-old female child presented to the senior surgeon complaining of acute heel pain after a gymnastic injury. She was diagnosed with a displaced, isolated fracture of the proximal calcaneal apophysis for which she underwent open reduction and internal fixation. On the magnetic resonance imaging (MRI) examination, we could diagnose that her injury was not chronic but acute because there was no change of intensity in the metaphyseal area. A combination of bioabsorbable suture tacks and pins was used to anatomically fix the fragment using the tension band wiring technique. At 2 years and 6 months follow-up, she had full range of motion, complete return of strength. We report here on the successful surgical treatment and the first case evaluated by MRI of an avulsion fracture of the calcaneal apophysis in a child.

  3. Calcaneal stress fracture: an adverse event following total hip and total knee arthroplasty: a report of five cases.

    PubMed

    Miki, Takaaki; Miki, Takahito; Nishiyama, Akihiro

    2014-01-15

    Stress fractures have been reported to occur in the pubis, femoral neck, proximal part of the tibia, and fabella during the postoperative period following total knee or total hip arthroplasty. However, to our knowledge, calcaneal stress fractures after total hip or total knee arthroplasty have not been reported in the English-language literature. Most orthopaedic surgeons are not familiar with calcaneal stress fractures that may occur in elderly patients after a total knee or total hip arthroplasty. We retrospectively reviewed the clinical features, imaging findings, and bone mineral content of the proximal part of the femur and the distal end of the radius in five patients who had a calcaneal stress fracture after a total knee or total hip arthroplasty. All patients were women with a mean age of 76.8 years. All fractures occurred in the calcaneus on the same side as the arthroplasty. The fracture appeared at a mean of 10.2 weeks postoperatively. All patients reported heel pain on walking. Swelling and local heat were found in four and three patients, respectively. Pain was elicited by squeezing the calcaneus in all patients. Early radiographs had normal findings in two patients, and an irregular sclerotic line appeared later in the radiographs of all patients. All fractures were treated conservatively. Four fractures healed uneventfully, but one fracture displaced. All patients had osteoporosis. Calcaneal stress fractures during the postoperative period following total knee or total hip arthroplasty may not be as rare as previously thought. Because clinical symptoms of the fracture appear insidiously and radiographic findings are absent or subtle in the early stage, a high index of suspicion is needed for orthopaedic surgeons to make the correct diagnosis. Magnetic resonance imaging or repeated radiographs may be necessary to make the correct diagnosis when no abnormality is apparent on the initial radiograph.

  4. Biomechanical Tolerance of Calcaneal Fractures

    PubMed Central

    Yoganandan, Narayan; Pintar, Frank A.; Gennarelli, Thomas A.; Seipel, Robert; Marks, Richard

    1999-01-01

    Biomechanical studies have been conducted in the past to understand the mechanisms of injury to the foot-ankle complex. However, statistically based tolerance criteria for calcaneal complex injuries are lacking. Consequently, this research was designed to derive a probability distribution that represents human calcaneal tolerance under impact loading such as those encountered in vehicular collisions. Information for deriving the distribution was obtained by experiments on unembalmed human cadaver lower extremities. Briefly, the protocol included the following. The knee joint was disarticulated such that the entire lower extremity distal to the knee joint remained intact. The proximal tibia was fixed in polymethylmethacrylate. The specimens were aligned and impact loading was applied using mini-sled pendulum equipment. The pendulum impactor dynamically loaded the plantar aspect of the foot once. Following the test, specimens were palpated and radiographs in multiple planes were obtained. Injuries were classified into no fracture, and extra-and intra-articular fractures of the calcaneus. There were 14 cases of no injury and 12 cases of calcaneal fracture. The fracture forces (mean: 7802 N) were significantly different (p<0.01) from the forces in the no injury (mean: 4144 N) group. The probability of calcaneal fracture determined using logistic regression indicated that a force of 6.2 kN corresponds to 50 percent probability of calcaneal fracture. The derived probability distribution is useful in the design of dummies and vehicular surfaces.

  5. Displaced intra-articular calcaneal fractures.

    PubMed

    Bajammal, Sohail; Tornetta, Paul; Sanders, David; Bhandari, Mohit

    2005-01-01

    Calcaneal fractures comprise 1 to 2 percent of all fractures. Approximately 75% of calcaneal fractures are intra-articular. The management of intra-articular calcaneal fractures remains controversial. Nonoperative treatment options include elevation, ice, early mobilization, and cyclic compression of the plantar arch. Operative treatment options include closed reduction and percutaneous pin fixation, open reduction and internal fixation, and arthrodesis. The effect of operative versus nonoperative treatment has been the focus of several comparative studies. This study was designed to determine the effect of operative treatment compared with nonoperative treatment on the rate of union, complications, and functional outcome after intra-articular calcaneal fracture in adults.

  6. Complications in operative fixation of calcaneal fractures

    PubMed Central

    Li, Ying; Bao, Rong-Hua; Jiang, Zhi-Qiang; Wu, Huo-Yan

    2016-01-01

    Objective: The purpose of this study focused on a number of factors that have been implicated in calcaneal complications and find the incidence of wound complications. Methods: This was a retrospective study. A total of 162 patients (176 feet) who underwent calcaneal fractures between 2007 and 2012 were included. The patient’s personal details, age, time from injury to surgery, cause of injury, type of fracture, operative details, operating and tourniquet times were collected from hospital computers and paper records. Evidence of complications including wound infection, wound necrosis, pain, malunion, nonunion, impingement, loss of fixation, ect were studied. Results: Forty-seven of one hundred and seventy-six fractures (26.704%) had complications, wound infection was noted in seven fractures (3.977%), twelve fractures developed necrosis (6.818%), 14 fractures (7.955%) developed pain. Malunion was found in five fractures (2.841%), nonunion in two fractures (1.136%) and loss of fixation in four fractures (2.272%). Three neurologic injury was also seen in our study (1.705%). Operating time, time from injury to surgery and type of fracture had some association with complications in operative fixation of calcaneal fractures, which showed a statistically significant improvement (P=0.000, 0.031, 0.020, respectively), but there were no evidence that age and tourniquet time affect the incidence of complication after calcaneal fracture surgery (P=0.119, 0.682, respectively). Conclusions: Despite developments in the surgical treatment of calcaneal fracture, wound complications still remain inevitable. Advanced imaging techniques, less invasive surgical procedures, wealth of anatomical knowledge, surgical experience and better postoperative care should be ensured. PMID:27648028

  7. Computed tomography of calcaneal fractures

    SciT

    Heger, L.; Wulff, K.; Seddiqi, M.S.A.

    1985-07-01

    Computed tomography (CT) of 25 fractured calcanei was performed to investigate the potential of CT in evaluating the pattern and biomechanics of these fractures. The characteristic findings of typical fractures are presented, including the number and type of principal fragments, size and dislocation of the sustentacular fragment, and involvement of the anterior and posterior facets of the subtalar joint. In 17 cases, the calcaneus consisted of four or more fragments. Furthermore, in 17 cases the sustentacular fragment included all or part of the posterior facet joint. In 18 of the 25 cases, the sustentacular fragment was displaced. It is concludedmore » that well performed CT is an invaluable adjunct in understanding the fracture mechanism and in detecting pain-provoking impingement between the fibular malleolus and the tuberosity fragment.« less

  8. Operative treatment of intra-articular calcaneal fractures with calcaneal plates and its complications

    PubMed Central

    Rak, Vaclav; Ira, Daniel; Masek, Michal

    2009-01-01

    Background: In a retrospective study we analysed intra-articular calcaneal fracture treatment by comparing results and complications related to fracture stabilization with nonlocking calcaneal plates and locking compression plates. Materials and Methods: We performed 76 osteosynthesis (67 patients) of intra-articular calcaneal fractures using the standard extended lateral approach from February 2004 to October 2007. Forty-two operations using nonlocking calcaneal plates (group A) were performed during the first three years, and 34 calcaneal fractures were stabilized using locking compression plates (group B) in 2007. In the Sanders type IV fractures, reconstruction of the calcaneal shape was attempted. Depending on the type of late complication, we performed subtalar arthroscopy in six cases, arthroscopically assisted subtalar distraction bone block arthrodesis in six cases, and plate removal with lateral-wall decompression in five cases. The patients were evaluated by the AOFAS Ankle-Hindfoot Scale. Results: Wound healing complications were 7/42 (17%) in group A and 1/34 (3%) in group B. No patient had deep osseous infection or foot rebound compartment syndrome. Preoperative size of Böhler's angle correlated with postoperative clinical results in both groups. There were no late complications necessitating corrective procedure or arthroscopy until December 2008 in Group B. All late complications ccurred in Group A. The overall results according to the AOFAS Ankle Hindfoot Scale were good or excellent in 23/42 (55%) in group A and in 30/34 (85%) in group B. Conclusion: Open reduction and internal fixation of intra-articular calcaneal fractures has become a standard surgical method. Fewer complications and better results related to treatment with locking compression plates confirmed in comparison to nonlocking ones were noted for all Sanders types of intra-articular calcaneal fractures. Age and Sanders type IV fractures are not considered to be the contraindications

  9. [Avulsion fracture of the calcaneal tuberosity in athletes].

    PubMed

    Glanzmann, M; Veréb, L; Habegger, R

    2005-04-01

    Avulsion fractures of the calcaneal tuberosity are rare injuries. Several surgical treatment options have been described. The size of the calcaneal fragment is the limiting factor in choosing the method for restoration. Finding the right type of fixation modality remains challenging in this rare kind of injury. In the case presented one Mitek Super Anchor was used to reattach the small fragment of the tuberosity to the calcaneus. Stable fixation with bony reunion and excellent functional outcome were achieved by this technique within 10 weeks. Therefore, we recommend the use of an anchor system for the treatment of small fragment calcaneal avulsion fractures.

  10. Peroneal tendon displacement accompanying intra-articular calcaneal fractures.

    PubMed

    Toussaint, Rull James; Lin, Darius; Ehrlichman, Lauren K; Ellington, J Kent; Strasser, Nicholas; Kwon, John Y

    2014-02-19

    Peroneal tendon displacement (subluxation or dislocation) accompanying an intra-articular calcaneal fracture is often undetected and under-treated. The goals of this study were to determine (1) the prevalence of peroneal tendon displacement accompanying intra-articular calcaneal fractures, (2) the association of tendon displacement with fracture classifications, (3) the association of tendon displacement with heel width, and (4) the rate of missed diagnosis of the tendon displacement on radiographs and computed tomography (CT) scans and the resulting treatment rate. A retrospective radiographic review of all calcaneal fractures presenting at three institutions from June 30, 2006, to June 30, 2011, was performed. CT imaging of 421 intra-articular calcaneal fractures involving the posterior facet was available for review. The prevalence of peroneal tendon displacement was noted and its associations with fracture classification and heel width were evaluated. Peroneal tendon displacement was identified in 118 (28.0%) of the 421 calcaneal fracture cases. The presence of tendon displacement was significantly associated with joint-depression fractures compared with tongue-type fractures (p < 0.001). Only twelve (10.2%) of the 118 cases of peroneal tendon displacement had been identified in the radiology reports. Although sixty-five (55.1%) of the fractures with tendon displacement had been treated with internal fixation, the tendon displacement was treated surgically in only seven (10.8%) of these cases. Analysis of CT images showed a 28% prevalence of peroneal tendon displacement accompanying intra-articular calcaneal fractures. Surgeons and radiologists are encouraged to consider this association.

  11. Surgical treatment of intra-articular calcaneal fractures.

    PubMed

    Stapleton, John J; Zgonis, Thomas

    2014-10-01

    Most intra-articular calcaneal fractures are a result of high-energy trauma. The operative management of calcaneal fractures has been based on achieving anatomic reduction and minimizing complications of the compromised soft tissue envelope. The traditional extensile lateral approach offers advantages of achieving adequate fracture reduction with the risk of wound-healing complications and infection. Limited open reduction and internal fixation techniques with or without using external fixation focuses on achieving fracture reduction with less risk of wound complications but higher risk of malunion. This article discusses key points of operative management for various intra-articular calcaneal fracture patterns and clinical presentations. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. The new intra-articular calcaneal fracture classification system in term of sustentacular fragment configurations and incorporation of posterior calcaneal facet fractures with fracture components of the calcaneal body.

    PubMed

    Harnroongroj, Thossart; Harnroongroj, Thos; Suntharapa, Thongchai; Arunakul, Marut

    2016-10-01

    The aim of this study was to develop a new calcaneal fracture classification system which will consider sustentacular fragment configuration and relation of posterior calcaneal facet to calcaneal body. The new classification system used sustentacular fragment configuration and relation of posterior calcaneal facet fracture with fracture components of calcaneal body as key aspects of main types and subtypes. Between 2000 and 2014, 126 intraarticular calcaneal fractures were classified according to the new classification system by using computed tomography images. The new classification system was studied in term of reliability, correlation to choices of treatment, implant fixation and quality of fracture reduction. Types of sustentacular fragment comprised type A, B and C. Type A sustentacular fragment included sustentacular tali containing middle calcaneal facet. In Type B and C fractures sustentacular fragment included medial aspect and entire posterior calcaneal facet as a single unit, respectively. The fractures with type A, B and C sustentacular fragments were classified as main type A, B and C intra-articular calcaneal fractures. The main type A and B comprised 4 subtypes. Subtypes A1, A3, B1, and B3 associated with avulsion and bending fragments of calcaneal body. Subtype A2, B2, and B4 associated with burst calcaneal body. Subtype B4 was not found in the study. Main type C had no subtype and associated with burst calcaneal body. The data showed good reliability. The study showed that our new intra-articular calcaneal fracture classification system correlates to choices of treatment, implant fixation and quality of fracture reduction. Level IV, Study of Diagnostic Test. Copyright © 2016 Turkish Association of Orthopaedics and Traumatology. Production and hosting by Elsevier B.V. All rights reserved.

  13. Biomechanical comparison of locking plate and crossing metallic and absorbable screws fixations for intra-articular calcaneal fractures.

    PubMed

    Ni, Ming; Wong, Duo Wai-Chi; Mei, Jiong; Niu, Wenxin; Zhang, Ming

    2016-09-01

    The locking plate and percutaneous crossing metallic screws and crossing absorbable screws have been used clinically to treat intra-articular calcaneal fractures, but little is known about the biomechanical differences between them. This study compared the biomechanical stability of calcaneal fractures fixed using a locking plate and crossing screws. Three-dimensional finite-element models of intact and fractured calcanei were developed based on the CT images of a cadaveric sample. Surgeries were simulated on models of Sanders type III calcaneal fractures to produce accurate postoperative models fixed by the three implants. A vertical force was applied to the superior surface of the subtalar joint to simulate the stance phase of a walking gait. This model was validated by an in vitro experiment using the same calcaneal sample. The intact calcaneus showed greater stiffness than the fixation models. Of the three fixations, the locking plate produced the greatest stiffness and the highest von Mises stress peak. The micromotion of the fracture fixated with the locking plate was similar to that of the fracture fixated with the metallic screws but smaller than that fixated with the absorbable screws. Fixation with both plate and crossing screws can be used to treat intra-articular calcaneal fractures. In general, fixation with crossing metallic screws is preferable because it provides sufficient stability with less stress shielding.

  14. [Treatment of calcaneal avulsion fractures with twinfix suture anchors fixation].

    PubMed

    Zhao, Bin-xiu; Wang, Kun-zheng; Wang, Chun-sheng; Xie, Yue; Dai, Zhi-tang; Liu, Gang; Liu, Wei-dong

    2011-06-01

    For the calcaneal avulsion fracture, the current method is more commonly used screws or Kirschner wire to fix fracture fragment. This article intended to explore the feasibility and clinical efficacy for the treatment of avulsion fractures with TwinFix suture anchors. From July 2007 to November 2010, 21 patients were reviewed, including 15 males and 6 females, ranging in age from 49 to 65 years,with a mean of 58.7 years. Twelve patients had nodules in the right heel and 9 patients had nodules in the left heel. All the patients had closed fractures. The typical preoperative symptoms of the patients included pain in the upper heel and weak in heel lift. Body examination results: palpable sense of bone rubbing in the back of the heel, and swelling in the heel. Surgery treatment with TwinFix suture anchors performed as follows : to fix TwinFix suture anchors into the calcaneal body, then to drill the fracture block, to make the double strand suture through the fracture holes, to knot the suture eachother to fix the block, and to use stitch to fix the remaining suture in the Achilles tendon in order to improve the block fixation. The criteria of the AOFAS Foot and Ankle Surgery by the United States Association of ankle-rear foot functional recovery was used to evaluate the Achilles tendon. Total average score was (95.5 +/- 3.12) points, including pain items of(38.5 +/- 2.18) points,the average score of functional items of (49.5 +/- 3.09) points,and power lines of 10 points in all patients. Twenty-one patients got an excellent result, 16 good and 5 poor. The methods of treatment for the calcaneal avulsion fractures with TwinFix suture anchors is a simple operation, and have excellent clinical effect, which is worthy of promotion.

  15. [Operative treatment of displaced intra-articular calcaneal fractures].

    PubMed

    Zwipp, H; Rammelt, S; Amlang, M; Pompach, M; Dürr, C

    2013-12-01

    Anatomic reduction of displaced intra-articular calcaneal fractures with restoration of height, length, and axial alignment and reconstruction of the subtalar and calcaneocuboid joints. Displaced intra-articular calcaneal fractures with incongruity of the posterior facet of the subtalar joint, loss of height, and axial malalignment. High perioperative risk, soft tissue infection, advanced peripheral arterial disease (stage III), neurogenic osteoarthropathy, poor patient compliance (e. g., substance abuse). Extended lateral approach with the patient placed on the uninjured side. Reduction of the anatomic shape and joint surfaces according to the preoperative CT-based planning. Reduction of the medial wall and step-wise reconstruction of the posterior facet from medial to lateral. Reduction of the tuberosity and anterior process fragments to the posterior joint block and temporary fixation with Kirschner wires. Internal fixation with an anatomic lateral plate in a locking or nonlocking mode. Alternatively less invasive internal fixation with a calcaneus nail over a sinus tarsi approach for less severe fracture types. The lower leg is immobilized in a brace until the wound is healed. Range of motion exercises of the ankle and subtalar joints are initiated on the second postoperative day. Patients are mobilized in their own shoe with partial weight bearing of 20 kg for 6-12 weeks depending on fracture severity and bone quality. Over a 4-year period, 163 patients with 184 displaced, intra-articular calcaneal fractures were treated with a lateral plate via an extended approach. In all, 102 patients with 116 fractures were followed for a mean of 8 years. A surgical revision was necessary in 4 cases (3.4%) of postoperative hematoma, 2 (1.7%) superficial and 5 (4.3%) deep infections. Of the latter, 2 patients needed a free flap for definite wound coverage, no calcanectomy or amputation was needed. Secondary subtalar fusion for symptomatic posttraumatic arthritis was

  16. Reconstruction of soft tissue after complicated calcaneal fractures.

    PubMed

    Koski, E Antti; Kuokkanen, Hannu O M; Koskinen, Seppo K; Tukiainen, Erkki J

    2004-01-01

    A total of 35 flap reconstructions were done to cover exposed calcaneal bones in 31 patients. All patients had calcaneal fractures, 19 of which were primarily open. Soft tissue reconstruction for the closed fractures was indicated by a postoperative wound complication. A microvascular flap was used for reconstruction in 21 operations (gracilis, n = 11; anterolateral thigh, n = 5; rectus abdominis, n = 3; and latissimus dorsi, n = 2). A suralis neurocutaneous flap was used in eight, local muscle flaps in three, and local skin flaps in three cases. The mean follow-up time was 14 months (range 3 months-4 years). One suralis flap failed and was replaced by a latissimus dorsi flap. Necrosis of the edges that required revision affected three flaps. Deep infection developed in two patients and delayed wound healing in another four. During the follow-up the soft tissues healed in all patients and there were no signs of calcaneal osteitis. Flaps were considered too bulky in five patients. Soft tissues heal most rapidly with microvascular flaps. In the long term, gracilis muscle covered with free skin grafts gives a good contour to the foot. The suralis flap is reliable and gives a good final aesthetic outcome. Local muscles can be transposed for reconstruction in small defects.

  17. [New techniques in the operative treatment of calcaneal fractures].

    PubMed

    Rammelt, S; Amlang, M; Sands, A K; Swords, M

    2016-03-01

    The ideal treatment of displaced intra-articular calcaneal fractures is still controversially discussed. Because of the variable fracture patterns and the vulnerable soft tissue coverage an individual treatment concept is advisable. In order to minimize wound edge necrosis associated with extended lateral approaches, selected fractures may be treated percutaneously or in a less invasive manner while controlling joint reduction via a sinus tarsi approach. Fixation in these cases is achieved with screws, intramedullary locking nails or modified plates that are slid in subcutaneously. A thorough knowledge of the three dimensional calcaneal anatomy and open reduction maneuvers is a prerequisite for good results with less invasive techniques. Early functional follow-up treatment aims at early rehabilitation independent of the kind of fixation. Peripheral fractures of the talus and calcaneus frequently result from subluxation and dislocation at the subtalar and Chopart joints. They are still regularly overlooked and result in painful arthritis if left untreated. If an exact anatomical reduction of these intra-articular fractures is impossible, resection of small fragments is indicated.

  18. Minimally invasive (sinus tarsi) approach for calcaneal fractures.

    PubMed

    Wang, Zhe; Wang, Xiu Hui; Li, Sheng Long; Tang, Xin; Fu, Bei Gang; Wang, Ming Hui; Xia, Sheng Li

    2016-12-23

    According to the anatomic characteristics of the calcaneus and the sinus tarsi approach, we designed a combined plate. The goal of this study was to retrospectively assess the functional outcomes and complications of treatment with our self-designed plate. From March 2014 to October 2015, 18 patients with closed calcaneal fractures (14 Sanders type II and 4 type III) were treated with our combined locking plate through a minimally invasive sinus tarsi approach. All patients underwent both clinical and radiological evaluations. The follow-up duration for all patients ranged from 6 to 13.5 months. The radiographs demonstrated significant corrections of the calcaneal width, length, height, Böhler angle, and Gissane angle from preoperatively to 3 months postoperatively and the last follow-up. However, there were no significant differences in the variables between 3 months postoperatively and the last follow-up. The mean Maryland foot score was 88.1 ± 8.8, in which excellent outcomes were achieved in 11 patients, good in 4, and fair in 3 (excellent and good rate, 83.3% (15 of 18)). No statistical significances in the mean Maryland foot score (88.1 ± 8.8 vs 87.8 ± 10.1, p = 0.9), and the excellent and good rate (85.7 vs 75.0%, p = 1.0) was found between type II and type III fractures. No complications were observed in all fractured feet. Treatment with our self-designed combined plate through a sinus tarsi approach may be safe and effective for type II and type III calcaneal fractures.

  19. Primary stability of an intramedullary calcaneal nail and an angular stable calcaneal plate in a biomechanical testing model of intraarticular calcaneal fracture.

    PubMed

    Goldzak, M; Simon, P; Mittlmeier, T; Chaussemier, M; Chiergatti, R

    2014-01-01

    Nowadays, open anatomic reduction and internal fixation can be considered as a valuable treatment for displaced intra-articular fractures of the calcaneus. However, the application of a calcaneal plate via an extensile lateral approach is at risk for a substantial rate of complications including delayed healing, skin necrosis, or infection. There is some evidence that a limited exposure might contribute to a decreased soft tissue complication rate bearing in mind that most minimally invasive techniques have to accept a reduced primary stability compared with the open application of an angular stable plate. Recently, an intrafocal minimal invasive reduction technique has been established employing an intramedullary nail for fracture stabilisation and support of the subtalar joint. The aim of this study was to compare the primary biomechanical performance of the new device versus lateral angular stable plating. Biomechanical testings were performed on 14 human cadaveric feet (7 pairs). Dry calcaneal bones were fractured resulting in a Sanders type IIB fracture pattern and fixed by either a calcaneal locking plate or an intramedullary calcaneal nail. Compressive testing via the corresponding talus was employed at a constant loading velocity until failure with an universal testing machine and a specific mounting device to avoid any shear forces. Apart from the data of the load deformation diagram the relative motion of the fracture elements during loading was recorded by 8 extensometric transducers. After failure the specimens were carefully examined to check the failure patterns. The displacement of the subtalar joint fragment was substantially lower in specimens fixed with the nail. Stiffness and load to failure were significantly higher after fixation with the intramedullary nail than after application of the angular stable plate. Failure with both fixation modes generally occurred at the anterior calcaneal process fragment. The primary stability of an

  20. Stabilization of displaced articular fragments in calcaneal fractures using bioabsorbable pin fixation: a technique guide.

    PubMed

    Min, William; Munro, Mark; Sanders, Roy

    2010-12-01

    Successful operative intervention in displaced intra-articular calcaneal fractures depends in part on the maintenance of an anatomic reduction of the posterior facet. This guide describes our use of bioabsorbable implants to solve this problem.

  1. Surgical management for avulsion fracture of the calcaneal tuberosity.

    PubMed

    Yu, Guang-rong; Pang, Qing-jiang; Yu, Xiao; Chen, Da-wei; Yang, Yun-feng; Li, Bing; Zhou, Jia-qian

    2013-08-01

    To discuss the operative methods and curative effect of calcaneal tuberosity fracture. A retrospective study was done to analyze 15 patients with calcaneal tuberosity fracture who received surgical management between January 2008 and June 2011. There were nine males and six females, with the age ranging from 31 to 68 years (average, 51.4 years). All the patients had unilateral acute injury, with the left foot in 7 cases and the right foot in 8 cases. According to the Beavis classification, there were three cases in type I and 12 cases in type II. All the cases in type I and 10 cases in type II were treated with open reduction and screw fixation. The other two cases in type II with larger fragment involving a portion of the subtalar joint were treated with plate and screw fixation. The effect of the treatment was assessed according to the ankle and hindfoot score system of American Orthopaedic Foot and Ankle Society (AOFAS) after the operation. Ten patients were followed up for 12 to 36 months (average, 20 months). The healing time in these patients ranged from 8 to 25 weeks (average, 12 weeks). The postoperative score ranged from 47 to 100 points (average, 91.1 points). Seven cases were rated as excellent, two as good, and one as poor. The rate of excellent and good was 90%. Necrosis of skin and soft tissue and exposure of the plate happened in one patient, who eventually healed after 3 weeks by debridement with plate preserved and peroneal artery perforator flap transplantation. Loss of reduction happened to another patient, who was treated with revision surgery by open reduction and screw fixation again. To patients with obvious fracture displacement, whose soft tissues are irritated severely, emergency open reduction and internal fixation operation should be offered to prevent the necrosis of the flaps as far as possible. To patients with small fractures, it is advisable to choose open reduction and large diameter screw fixation, while plate and screw fixation

  2. Soft tissue reconstruction for calcaneal fractures or osteomyelitis.

    PubMed

    Attinger, C; Cooper, P

    2001-01-01

    A systematic approach of the surgical management of a calcaneal fracture can minimize the potential of soft tissue complications. When reducing a closed calcaneal fracture, the incision used affects the postoperative complications. The L-shaped incision with the horizontal limb lying on the lateral glabrous junction ensures maximum blood flow to either side of the incision. Whether or not the wound can be closed primarily depends on the preexisting edema, the lost calcaneal height, and the delay between the fracture and reduction (Fig. 20). The wrinkle test is a good indicator that the incision can be closed primarily if the amount of height restored is minimal. If the edema is too great, steps should be taken to reduce it sufficiently to allow successful wound closure. If the wound, after reduction, is too wide to allow primary closure, an ADM flap laterally or an AHM flap medially should be used. For larger defects, a free flap should be considered. The three important steps to reconstruction of soft tissue defects around the calcaneus include good blood supply, a infection-free wound, and the simplest soft tissue reconstructive option that covers the wound successfully. Adequate blood supply can be determined by the use of Doppler. If the supply is inadequate, revascularization is necessary before proceeding. Achieving a clean wound requires aggressive debridement, intravenous antibiotics, and good wound care. Adjuncts that can help in achieving a clean wound include topical antibiotics (silver sulfadiazine), the VAC, and hyperbaric oxygen. Osteomyelitis has to be treated aggressively. Any suspicious bone has to be removed. Only clean, healthy, bleeding bone is left behind. Antibiotic beads can be useful when there is doubt as to whether the cancellous bone is infection-free. The beads are not a substitute for good debridement, however. Soft tissue reconstruction ranges from delayed primary closure to the use of microsurgical free flaps (Fig. 21). When bone or

  3. Calcaneal Insufficiency Fracture Secondary to Celiac Disease-Induced Osteomalacia: A Rare Cause of Heel Pain.

    PubMed

    Kose, Ozkan; Kilicaslan, Omer Faruk; Ozyurek, Selahattin; Ince, Ahmet

    2016-04-01

    Plantar fasciitis is a common cause of plantar heel pain; however, a broad spectrum of disorders may also present with plantar heel pain. A detailed history, physical examination, laboratory testing, and imaging studies may be necessary to reach an accurate diagnosis. Herein, the clinical presentation of a 33-year-old woman with calcaneal insufficiency fracture secondary to celiac disease-induced osteomalacia is presented, and its diagnosis and treatment are discussed. Calcaneal insufficiency fractures should be kept in mind in a patient with celiac disease that presents with heel pain. Therapeutic, Level IV: Case study. © 2015 The Author(s).

  4. Treatment of Displaced Intra-articular Calcaneal Fractures by Intramedullary Nail. Preliminary Report.

    PubMed

    Falis, Mirosław; Pyszel, Krystian

    2016-03-23

    Open reduction and plate stabilisation is a recognised method of treatment of intra-articular calcaneal fractures. The surgical approach to the calcaneal bone used in these procedures is associated with a high risk of complications. The aim of this paper is to present the author's experience with a new surgical method and analyse early outcomes of the treatment of calcaneal fractures by Calcanail intramedullary nailing. The study encompassed 17 patients (5 women and 12 men) with 18 calcaneal fractures (5 in the right foot and 13 in the left foot). The mean age of the patients was 47 years (range: 22-68 years). The mean time between the injury and surgery was 6 days (range: 3-14 days). The mean duration of follow-up was 12 months (range: 6-18 months). The fractures were classified according to the system presented by Guy Utheza. Bone union was achieved in all patients within 12 weeks of surgery. No infectious complications were observed. The mean AOFAS score was 82/100. Mean Bohler's angle was -3 degrees pre-operatively and +29 degrees post-operatively. 1. The use of Calcanail intramedullary nailing in the treatment of displaced intra-articular fractures is a minimally invasive procedure associated with a low risk of complications. 2. The innovative posterior approach allows for the intrafocal reduction of an articular surface fracture through the prepared intramedullary canal.

  5. Stress Fractures

    MedlinePlus

    Stress fractures Overview Stress fractures are tiny cracks in a bone. They're caused by repetitive force, often from overuse — such as repeatedly jumping up and down or running long distances. Stress fractures can also arise from normal use of ...

  6. [Long-term results of calcaneal fracture treatment by open reduction and internal fixation using a calcaneal locking compression plate from an extended lateral approach].

    PubMed

    Zeman, P; Zeman, J; Matejka, J; Koudela, K

    2008-12-01

    To report on the surgical treatment of intra-articular calcaneal fractures by open reduction and internal fixation with a calcaneal locking compression plate (LCP) from an extended lateral approach, and to retrospectively analyze the mid-term results in a group of patients treated by this technique. In the period from August 2005 till March 2007, a total of 49 patients with 61 calcaneal fractures were treated. Of these, 11 (18 %) were treated conservatively. Reduction combined with Kirschner-wire fixation was used in four fractures (6.6 %). Open reduction with internal calcaneal LCP fixation (ORIF- calcaneal LCP) from an extended lateral approach was carried out to treat 46 fractures (75.4 %) in 38 patients. The group evaluated here comprised 29 patients with 33 calcaneal fractures treated by ORIF-calcaneal LCP at a follow-up longer than 6 months. The fractures were classified on the basis of computer tomography (CT) findings as Sanders types I to IV. The group had two woman (6.9 %) and 27 men (93.1 %) with an average age of 34.2 years (range, 19-55 years). In 11 fractures (33.3 %), the primary treatment included filling a central cancellous bone defect area. Calcium phosphate bone substitute material (resorbable ChronOS) was used in nine cases (27.3 %), a self-solidifying hydroxyapatite implant was injected in two (6.1 %) cases (X3 Wright and Norian SRS, respectively), and a bone allograft was implanted in one case (3 %). Indicated for surgery were patients with an intra-articular calcaneal fracture, Sanders type II or type III, with articular surface displacement by more than 1 mm. Contraindications included age over sixty years, poor cooperation, smoking habits, peripheral vascular disease or skin infection. Surgery was performed only after oedema had resolved. The aim of our treatment was to achieve anatomical reconstruction of all articular surfaces, to restore the height, length, width and axis of the heel bone, to carry out primary stable osteosynthesis, and

  7. A Novel Technique for Closed Reduction and Fixation of Paediatric Calcaneal Fracture Dislocation Injuries

    PubMed Central

    Faroug, Radwane; Stirling, Paul; Ali, Farhan

    2013-01-01

    Paediatric calcaneal fractures are rare injuries usually managed conservatively or with open reduction and internal fixation (ORIF). Closed reduction was previously thought to be impossible, and very few cases are reported in the literature. We report a new technique for closed reduction using Ilizarov half-rings. We report successful closed reduction and screwless fixation of an extra-articular calcaneal fracture dislocation in a 7-year-old boy. Reduction was achieved using two Ilizarov half-ring frames arranged perpendicular to each other, enabling simultaneous application of longitudinal and rotational traction. Anatomical reduction was achieved with restored angles of Bohler and Gissane. Two K-wires were the definitive fixation. Bony union with good functional outcome and minimal pain was achieved at eight-weeks follow up. ORIF of calcaneal fractures provides good functional outcome but is associated with high rates of malunion and postoperative pain. Preservation of the unique soft tissue envelope surrounding the calcaneus reduces the risk of infection. Closed reduction prevents distortion of these tissues and may lead to faster healing and mobilisation. Closed reduction and screwless fixation of paediatric calcaneal fractures is an achievable management option. Our technique has preserved the soft tissue envelope surrounding the calcaneus, has avoided retained metalwork related complications, and has resulted in a good functional outcome. PMID:23819090

  8. Traumatic ipsilateral multiple open metatarsal and calcaneal fractures with first metatarsophalangeal joint dislocation: a case report.

    PubMed

    Ozkan, Namik Kemal; Unay, Koray; Cift, Hakan; Eceviz, Engin; Ozkan, Korhan

    2010-06-01

    A 17-year-old man fell from a height of 10 m onto his right forefoot and sustained ipsilateral calcaneal, comminuted cuboid, and second, third, and fourth metatarsal neck fractures and first metatarsophalangeal joint open dislocation. This report discusses this rare injury. The authors believe that initial debridement with immediate surgical fixation and reduction with appropriate antibiotic treatment saved the patient's extremity.

  9. Subtalar distraction osteogenesis for posttraumatic arthritis following intra-articular calcaneal fractures.

    PubMed

    Fan, Wei-Li; Sun, Hong-Zhen; Wu, Si-Yu; Wang, Ai-Min

    2013-03-01

    The most common treatment for old calcaneal fractures accompanied by subtalar joint injury is the use of subtalar in situ arthrodesis and subtalar distraction bone-block arthrodesis or osteotomy. This article describes the introduction of a novel surgical treatment, gradual subtalar distraction with external fixation and restoration of the calcaneal height, and presents an assessment of its efficacy. The protruding lateral calcaneus and the articular surfaces and subchondral bone of the posterior facet of the subtalar joint were surgically removed. An external fixator, attached with 2 pins in the subcutaneous tibia and 2 pins in the posterolateral calcaneus, was used to fix the subtalar joint for 7 to 10 days followed by gradual subtalar distraction at 1 mm/d. The lengthening procedure was stopped when the calcaneal height was restored according to radiography. The external fixator was removed after bone fusion. Seven cases of old calcaneal fractures accompanied by severe subtalar joint injury (8 feet) were treated using this method. Average follow-up was 14.3 months (range, 7-36 months). In all 7 cases (1 case of both feet), the postoperative wound healed primarily. The calcaneal heights of all 8 feet were partially restored. Subtalar joint bone fusion was completed within 4 to 6 months after the operation. The average preoperative American Orthopedic Foot & Ankle Society (AOFAS) hindfoot score was 25.3, and the average postoperative AOFAS score was 76.3. Subtalar distraction osteogenesis with external fixation was a novel and effective method for the treatment of old calcaneal fractures accompanied by severe subtalar joint injury in this small group of patients. Level IV, retrospective case series.

  10. Treatment of Calcaneal Fracture With Severe Soft Tissue Injury and Osteomyelitis: A Case Report.

    PubMed

    Karns, Michael; Dailey, Steven K; Archdeacon, Michael T

    2015-01-01

    Advancements in surgical technique have resulted in the ability to reconstruct lower extremity injuries that would have previously been treated by amputation. Currently, a paucity of data is available specifically addressing limb amputation versus reconstruction for calcaneal fractures with severe soft tissue compromise. Reconstruction leaves the patient with their native limb; however, multiple surgeries, infections, chronic pain, and a poor functional outcome are very real possibilities. We present the case of a complex calcaneal fracture complicated by soft tissue injury and osteomyelitis that highlights the importance of shared decision-making between patient and surgeon when considering reconstruction versus amputation. This case exemplifies the need for open communication concerning the risks and benefits of treatment modalities while simultaneously considering the patient's expectations and desired outcomes. Copyright © 2015 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  11. Repeated Stress Fractures in an Amenorrheic Marathoner: A Case Conference.

    ERIC Educational Resources Information Center

    Sutton, John R.; Nilson, Karen L.

    1989-01-01

    Presents a case conference by 2 experts on the relationship between a 26-year-old marathoner's amenorrhea and her sustained unusual stress fractures in 4 ribs (plus previous similar fractures of the calcaneal, navicular, metatarsal, and tibial bones). The experts conclude that she suffers many manifestations of overtraining. (SM)

  12. Achilles tenodesis for calcaneal insufficiency avulsion fractures associated with diabetes mellitus.

    PubMed

    Choi, Youngrak; Kwon, Young-Woo; Sim, Young-Suk; Kim, Taeho; Song, Dayoung; Lee, Soohyun

    2017-12-13

    Calcaneal insufficiency avulsion (CIA) fractures often present with neuropathic etiology, such as Charcot neuroarthropathy (CN). Under the same surgical procedures, the outcomes of CIA fractures are less desirable, compared to the outcomes of the traumatic calcaneal avulsion fractures. Here, the study suggests Achilles tenodesis technique using suture anchor after resection of the CIA fracture fragments could provide satisfactory clinical results in the cases of surgically indicated CIA fractures. This retrospective study included seven patients of calcaneal avulsion fracture who had underlying diabetes mellitus (DM) and no specific traumatic event. The patients were treated with Achilles tenodesis techniques for their CIA fractures. Achilles tenodesis was performed using suture anchor with removal of the fracture fragments. The patients were evaluated with the Foot and Ankle Outcome Score (FAOS), visual analogue scale (VAS), single-heel rise test, and X-ray images on their final follow-ups. Initially, three of the CIA fracture cases treated with traditional open reduction and internal fixation reported pullout failure. Consequently, all patients received Achilles tenodesis using suture anchor after bone fragment resection and had good clinical outcomes. Only one subject with low compliance reported poor outcome. The FAOS of each patient were obtained at a mean of 16.3 months after surgery. The results are as follows: pain 80.6 (SD = 6.2), symptom 83.8 (SD = 4.9), activities of daily living 80.5 (SD = 8.0), sport and recreation function 75.6 (SD = 11.93), and foot- and ankle-related quality of life 77.9 (SD = 6.7). On their final follow-ups, the average VAS was 2.6 (range, 1 to 4). Achilles tenodesis using suture anchor after bone fragment resection achieved competent clinical results in the patients with CIA fractures. The study proposes that this surgical procedure could be an appropriate treatment option for patients with CIA fractures. The

  13. Plantar Pressure Anomalies After Open Reduction With Internal Fixation of High-Grade Calcaneal Fractures.

    PubMed

    Hetsroni, Iftach; Ben-Sira, David; Nyska, Meir; Ayalon, Moshe

    2014-07-01

    Plantar pressure abnormalities after open reduction with internal fixation (ORIF) of intra-articular calcaneal fractures have been observed previously, but high-grade fractures were not selectively investigated and follow-up times were shorter than 2 years. The purpose of this study was to characterize plantar pressure anomalies in patients with exclusively high-grade calcaneal fractures after ORIF with a minimum 2 years of follow-up, and to test the association between plantar pressure distribution and the clinical outcome. The orthopaedic registry was reviewed to identify patients with isolated high-grade calcaneal fractures (Sanders types III-IV) who were operated on and had a minimum 2 years of follow-up. Sixteen patients were evaluated. Mean age was 47 years and follow-up was between 2 and 6 years. The Pedar-Mobile system was used to measure 3 loading and 3 temporal variables and compare these between the operated and the uninjured limbs. Mean American Orthopaedic Foot and Ankle Society (AOFAS) score was 76 ± 7 at latest follow-up. Bohler's angle was 5 ± 8 degrees before surgery and 25 ± 7 degrees at latest follow-up. Stance was shorter in operated limbs (P = .001). Timing of the peak of pressure was delayed in operated limbs under the hallux and the second toe (P ≤ .03). Peak pressure, force time integral, and pressure time integral were increased under the lateral midfoot (P ≤ .03) and decreased under the second metatarsal (P ≤ .03). Force time integral was decreased under the first metatarsal (P = .02) and under the hallux and the lateral toes (P ≤ .05). Increased loading under the lateral midfoot and decreased loading under the lateral toes were correlated with poorer clinical outcome (r = -.53, P < .05, and r = .63, P < .01, respectively). Side-to-side plantar pressure mismatch persisted at more than 2 years after ORIF of high-grade calcaneal fractures performed via lateral approach, despite improvement of Bohler's angle. This was characterized

  14. Radiography versus computed tomography for displacement assessment in calcaneal fractures.

    PubMed

    Ogawa, Brent K; Charlton, Timothy P; Thordarson, David B

    2009-10-01

    Coronal computed tomography (CT) scans are commonly used in fracture classification systems for calcaneus fractures. However, they may not accurately reflect the amount of fracture displacement. The purpose of this paper was to determine whether lateral radiographs provide superior assessment of the displacement of the posterior facet compared to coronal CT scans. Lateral radiographs of calcaneus fractures were compared with CT coronal images of the posterior facet in 30 displaced intra-articular calcaneus fractures. The average patient age was 39 years old. Using a Picture Archiving and Communication System (PACS), measurements were obtained to quantify the amount of displacement on the lateral radiograph and compared with the amount of depression on corresponding coronal CT scans. On lateral radiographs, the angle of the depressed portion of the posterior facet relative to the undersurface of the calcaneus averaged 28.2 degrees; Bohler's angle averaged 12.7 degrees. These numbers were poorly correlated (r = 0.25). In corresponding CT images from posterior to anterior, the difference in the amount of displacement of the lateral portion of the displaced articular facet versus the nondisplaced medial, constant fragment, was minimal and consistently underestimated the amount of displacement. Underestimation of the amount of depression and rotation of the posterior facet fragment was seen on the coronal CT scan. We attribute this finding to the combined rotation and depression of the posterior facet which may not be measured accurately with the typical semicoronal CT orientation. While sagittal reconstructed images would show this depression better, if they are unavailable we recommend using lateral radiographs to better gauge the amount of fracture displacement.

  15. Outcome Determining Factors for displaced Intra-articular Calcaneal Fractures treated operatively

    PubMed Central

    Chan, KL; Idham, HM; Izani, IM; Nahulan, T

    2015-01-01

    Introduction: Calcaneal fractures are caused by high energy trauma and mostly are intra-articular fractures. Nondisplaced intra-articular calcaneal fracture (IACF) can be treated non-operatively. However, displaced intra-articular need to be reduced and fixed anatomically to facilitate early ankle rehabilitation and minimize functional impairment. This study was done to find out the outcome of the IACF patients who underwent operative treatment. Methods: 62 patients with IACF were selected in this study and had been followed up from June 2009 to May 2013. They were placed into two groups; the operative treated and non-operative treated groups. Bilateral ankle lateral view plain radiographs were taken for comparison of the Bohler and Gissane angles. Both groups of patients were assessed by the Maryland Foot Score (MFS) and the SF-36v2 general health survey questionnaire. The ability of the patients to perform activity of daily living (ADL) and /or return to work (RTW) was assessed as well. Results: The operative treatment group of displaced IACF patients achieved no significant better scores in the mean MFS and SF-36v2 mean scores as compared to non operated cases. There was no difference in RTW between the 2 groups, but earlier ADL was recorded in the operated group. However, this study had found 5 associated factors which causes major effect to the patients’ outcome to treatment. Conclusions: The patient’s compliance with post-operative rehabilitation regimen were found to be significantly related with the outcomes. PMID:28611903

  16. Sanders II type calcaneal fractures: a retrospective trial of percutaneous versus operative treatment.

    PubMed

    Wang, Ye-ming; Wei, Wan-fu

    2015-02-01

    The purpose of this study was to compare the clinical results of percutaneous reduction and Steinman pin fixation for Sanders II calcaneal fractures with those of operative management through an extensile lateral approach. Fifty-three patients treated with standard open reduction and internal fixation (ORIF group) and 54 patients who had undergone percutaneous reduction and Steinman pin fixation (CRIF group) were retrospectively reviewed. There were no differences between the groups regarding sex, age or fracture classification. Pain and functional outcome were evaluated with a visual analogue scale (VAS) and American Orthopaedic Foot and Ankle Society (AOFAS) scores. Wound complications and radiological results were compared. At a mean follow-up of 40.4 months (24 to 56 months), there were no differences between the two groups in mean AOFAS score, VAS score or radiologically determined variables. Two cases of deep infection and six of poor wound healing occurred in the ORIF group and none in the CRIF group. Subtalar and ankle motion was found to be better in the CRIF group. Percutaneous reduction and Steinman pin fixation minimizes complications and achieves functional outcomes comparable to those of the open techniques in patients with Sanders II calcaneal fractures. © 2015 Chinese Orthopaedic Association and Wiley Publishing Asia Pty Ltd.

  17. Correlation between Parameters of Calcaneal Quantitative Ultrasound and Hip Structural Analysis in Osteoporotic Fracture Patients

    PubMed Central

    Zheng, Hailiang; Li, Ming; Yin, Pengbin; Peng, Ye; Gao, Yuan; Zhang, Lihai; Tang, Peifu

    2015-01-01

    Background Calcaneal quantitative ultrasound (QUS), which is used in the evaluation of osteoporosis, is believed to be intimately associated with the characteristics of the proximal femur. However, the specific associations of calcaneal QUS with characteristics of the hip sub-regions remain unclear. Design A cross-sectional assessment of 53 osteoporotic patients was performed for the skeletal status of the heel and hip. Methods We prospectively enrolled 53 female osteoporotic patients with femoral fractures. Calcaneal QUS, dual energy X-ray absorptiometry (DXA), and hip structural analysis (HSA) were performed for each patient. Femoral heads were obtained during the surgery, and principal compressive trabeculae (PCT) were extracted by a three-dimensional printing technique-assisted method. Pearson’s correlation between QUS measurement with DXA, HSA-derived parameters and Young’s modulus were calculated in order to evaluate the specific association of QUS with the parameters for the hip sub-regions, including the femoral neck, trochanteric and Ward’s areas, and the femoral shaft, respectively. Results Significant correlations were found between estimated BMD (Est.BMD) and BMD of different sub-regions of proximal femur. However, the correlation coefficient of trochanteric area (r = 0.356, p = 0.009) was higher than that of the neck area (r = 0.297, p = 0.031) and total proximal femur (r = 0.291, p = 0.034). Furthermore, the quantitative ultrasound index (QUI) was significantly correlated with the HSA-derived parameters of the trochanteric area (r value: 0.315–0.356, all p<0.05) as well as with the Young’s modulus of PCT from the femoral head (r = 0.589, p<0.001). Conclusion The calcaneal bone had an intimate association with the trochanteric cancellous bone. To a certain extent, the parameters of the calcaneal QUS can reflect the characteristics of the trochanteric area of the proximal hip, although not specifically reflective of those of the femoral neck

  18. [CT morphometry for calcaneal fractures and comparison of the Zwipp and Sanders classifications].

    PubMed

    Andermahr, J; Jesch, A B; Helling, H J; Jubel, A; Fischbach, R; Rehm, K E

    2002-01-01

    The aim of the study is to correlate the CT-morphological changes of fractured calcaneus and the classifications of Zwipp and Sanders with the clinical outcome. In a retrospective clinical study, the preoperative CT scans of 75 calcaneal fractures were analysed. The morphometry of the fractures was determined by measuring height, length diameter and calcaneo-cuboidal angle in comparison to the intact contralateral side. At a mean of 38 months after trauma 44 patients were clinically followed-up. The data of CT image morphometry were correlated with the severity of fracture classified by Zwipp or Sanders as well as with the functional outcome. There was a good correlation between the fracture classifications and the morphometric data. Both fracture classifying systems have a predictive impact for functional outcome. The more exacting and accurate Zwipp classification considers the most important cofactors like involvement of the calcaneo-cuboidal joint, soft tissue damage, additional fractures etc. The Sanders classification is easier to use during clinical routine. The Zwipp classification includes more relevant cofactors (fracture of the calcaneo-cuboidal-joint, soft tissue swelling, etc.) and presents a higher correlation to the choice of therapy. Both classification systems present a prognostic impact concerning the clinical outcome.

  19. [Manipulative reduction and external fixation with cardboard splint for the treatment of calcaneal fractures: a 60-case report].

    PubMed

    Hao, Bo-Chuan; Xie, Ke-Bo

    2014-07-01

    To investigate the therapeutic effects of manipulative reduction for calcaneal fractures. From January 2009 to June 2012, 53 cases (60 affected feet) of Sanders type I-IV calcaneal fractures were treated by manipulative reduction and external fixation with cardboard splint,including 45 males and 8 females with an average age of (33.5 +/- 1.54) years old ranging from 18 to 65. The course of disease ranged 0.5 h to 7 d. Before treatment the feet were swelling, ache and activity limitation in evidence, some feet were wide flat deformity, the cortical bone was broken in the imaging examination. All selected cases were evaluated using Creighton-Nebraska health foundation assessment scale for fractures of calcaneus. All cases were followed up at 12 months after treatment, 13 feet got excellent curative effect, 34 good, 11 moderate and 2 poor. Manipulative reduction for Sanders type I-IV calcaneal fractures could get excellent curative effect. Manipulative reduction for calcaneal fractures could avoid surgical trauma while assure high curative effects. Manipulative reduction is not only economical and easy therapy, but also can restore maximum function of the calcaneus with few complications and facilitate early rehabilitation of ankle and joint function.

  20. [Treatment of calcaneal fractures with a locking nail (C-Nail)].

    PubMed

    Pompach, M; Carda, M; Amlang, M; Zwipp, H

    2016-06-01

    Anatomic reconstruction of the posterior facet by primary stabilization of the calcaneal fracture with a locking nail. All intraarticular calcaneal fractures and unstable two-part fractures independent of the degree of closed/open soft tissue trauma. High perioperative risk, soft tissue infection, beak fracture (type II fracture) and still open apophysis. Anatomic reduction of the posterior facet using a sinus tarsi approach. Reduction and temporary fixation of the sustentacular, tuberosity, and anterior process fragments with 1.8-2.0 mm Kirschner wires. Thereafter, the C-Nail (calcaneus nail) is introduced with its guiding device stabilizing the sustentacular, tuberostity, and anterior process fragments through its three guiding arms with 6 or 7 locking screws. Passive and active motion starts on postoperative day 2. Lymph drains help reduce swelling. Partial weightbearing with 20 kg for 6-8 weeks in the patient's own shoes is recommended. X‑ray controls are done at 4 and 8 weeks as well as after 6 and 12 months. A total of 107 calcaneal fractures treated with the C-Nail between 2011 and 2014 were evaluated according to the AOFAS score 6 months and 1 year after surgery. The measured values were on average 93.0 (range 65-100) points at 6 months and 94.1 (range 75-100) points 12 months after the surgery. Böhler's angle with initial traumatic values of 6.2° (-30 to +13°) improved postoperatively to 31.8°, after 3 months slightly decreased to 29.6°, and after 12 months to 28.3°. There were 2 cases of superficial wound necrosis (1.9 %) and 1 case a deep infection (0.93 %) with need of early C-Nail removal.

  1. Discriminative capacity of calcaneal quantitative ultrasound and of osteoporosis and fracture risk factors in postmenopausal women with osteoporotic fractures.

    PubMed

    Hernández, J L; Marin, F; González-Macías, J; Díez-Pérez, A; Vila, J; Giménez, S; Galán, B; Arenas, M S; Suárez, F; Gayola, L; Guillén, G; Sagredo, T; Belenguer, R; Moron, A; Arriaza, E

    2004-04-01

    Bone fragility fractures constitute the principal complication of osteoporosis. The identification of individuals at high risk of sustaining osteoporotic fractures is important for implementing preventive measures. The purpose of this study is to analyze the discriminative capacity of a series of osteoporosis and fracture risk factors, and of calcaneal quantitative ultrasound (QUS), in a population of postmenopausal women with a history of osteoporotic fracture. A cross-sectional analysis was made of a cohort of 5195 women aged 65 or older (mean +/- SD: 72.3 +/- 5.4 years) seen in 58 primary care centers in Spain. A total of 1042 women (20.1%) presented with a history of osteoporotic fracture. Most fractures (93%) were non-vertebral. Age-adjusted odds ratios corresponding to each decrease in one standard deviation of the different QUS parameters ranged from 1.47 to 1.55 (P < 0.001) for fractures. The age-adjusted multivariate analysis yielded the following risk factors independently associated with a history of osteoporotic fracture: number of fertile years, a family history of fracture, falls in the previous year, a history of chronic obstructive airway disease, the use of antiarrhythmic drugs, and a low value for any of the QUS parameters. The area under the receiver operating characteristic curve of the best model was 0.656. In summary, a series of easily assessable osteoporotic fracture risk factors has been identified. QUS was shown to discriminate between women with and without a history of fracture, and constitutes a useful tool for assessing fracture risk. Various of the vertebral and hip fracture risk factors frequently cited in North American and British populations showed no discriminative capacity in our series--thus suggesting that such factors may not be fully applicable to our population and/or to the predominant type of fractures included in the present study.

  2. Surgical treatment of displaced intra-articular calcaneal fracture using a single small lateral approach

    PubMed Central

    El-Adl, Gamal; Hassanin, Ehab Y.; Abdellatif, M-Serry

    2010-01-01

    The objective of this study was to evaluate the outcome of semi-open reduction and minimal internal fixation through a single small lateral approach as a minimally invasive technique for treatment of displaced intra-articular calcaneal fractures. This prospective study was conducted on eighteen patients (16 men and 2 women). The average age was 37.7 (22–55). The most common cause of injury was a fall from height in fourteen patients. Patients were operated on within a mean time of 4.8 days of admission (1–11 days) and were followed up for an average period of 24.1 months (6–39 months). Patients were evaluated clinically using the Creighton-Nebraska Heath Foundation Assessment score of Crosby and Fitzgibbons (J Bone Joint Surg (Am) 72-A:852–859, 1990). The scoring system proposed by Knirk and Jupiter was used for radiological assessment of the posterior subtalar joint (Knirk and Jupiter in J Bone Joint Surg (Am) 68-A: 647–659, 1986). The skin incision healed in all cases without necrosis, infection, or sural nerve injury. All fractures healed after an average of 8 weeks (7–10 weeks), and patients returned to the routine daily activities after an average time of 4.3 months (3–7 months). In conclusion, semi-open reduction and minimal internal fixation through a small lateral approach is an effective treatment for carefully selected cases of displaced intra-articular calcaneal fractures. PMID:21811904

  3. Interlocking Nailing Versus Interlocking Plating in Intra-articular Calcaneal Fractures: A Biomechanical Study.

    PubMed

    Reinhardt, Sophia; Martin, Heiner; Ulmar, Benjamin; Döbele, Stefan; Zwipp, Hans; Rammelt, Stefan; Richter, Martinus; Pompach, Martin; Mittlmeier, Thomas

    2016-08-01

    Open reduction and internal fixation with a plate is deemed to represent the gold standard of surgical treatment for displaced intra-articular calcaneal fractures. Standard plate fixation is usually placed through an extended lateral approach with high risk for wound complications. Minimally invasive techniques might avoid wound complications but provide limited construct stability. Therefore, 2 different types of locking nails were developed to allow for minimally invasive technique with sufficient stability. The aim of this study was to quantify primary stability of minimally invasive calcaneal interlocking nail systems in comparison to a variable-angle interlocking plate. After quantitative CT analysis, a standardized Sanders type IIB fracture model was created in 21 fresh-frozen cadavers. For osteosynthesis, 2 different interlocking nail systems (C-Nail; Medin, Nov. Město n. Moravě, Czech Republic; Calcanail; FH Orthopedics SAS; Heimsbrunn, France) as well as a polyaxial interlocking plate (Rimbus; Intercus GmbH; Rudolstadt, Germany) were used. Biomechanical testing consisted of a dynamic load sequence (preload 20 N, 1000 N up to 2500 N, stepwise increase of 100 N every 100 cycles, 0.5 mm/s) and a load to failure sequence (max. load 5000 N, 0.5 mm/s). Interfragmentary movement was detected via a 3-D optical measurement system. Boehler angle was measured after osteosynthesis and after failure occurred. No significant difference regarding load to failure, stiffness, Boehler angle, or interfragmentary motion was found between the different fixation systems. A significant difference was found with the dynamic failure testing sequence where 87.5% of the Calcanail implants failed in contrast to 14% of the C-Nail group (P < .01) and 66% of the Rimbus plate. The highest load to failure was observed for the C-Nail. Boehler angle showed physiologic range with all implants before and after the biomechanical tests. Both minimally invasive interlocking nail systems

  4. Introduction of a New Locking Nail for Treatment of Intraarticular Calcaneal Fractures.

    PubMed

    Zwipp, Hans; Paša, Libor; Žilka, Luboš; Amlang, Michael; Rammelt, Stefan; Pompach, Martin

    2016-03-01

    To reduce the complication rate associated with open reduction and internal fixation of displaced intraarticular calcaneal fractures through extensile approaches, a locking nail system (C-Nail) was developed for internal fixation. Prospective case-control study. Two level I trauma centers (university hospital) and 1 large regional hospital in the Czech Republic and Germany. One hundred three patients (89 male and 14 female; mean age, 45.6 years) with 106 calcaneal fractures were treated between February 2011 and October 2013. In all 106 cases, the stainless steel C-Nail with a length of 65 mm, a diameter of 8 mm, and 7 locking options was used for internal fixation. Previous reduction of the posterior facet was performed in 15 cases percutaneously, assisted by arthroscopy and fluoroscopy, and in 91 cases by a sinus tarsi approach. The reduced joint surface was fixed by 1 or 2 compression screws. All other fragments were fixed after reduction and temporary K-wire fixation with the C-Nail introduced percutaneously through the tuberosity and 5 to 6 interlocking screws. The latter were introduced into the sustentacular, the tuberosity, and the anterior process fragments with an aiming device consisting of 3 arms. Patients were assessed for complications, restoration of Böhler angle, posterior facet reduction with postoperative computed tomography, and weight-bearing radiographs at 6 months. Functional outcome was assessed using the American Orthopaedic Foot & Ankle Society (AOFAS) ankle/hindfoot scale after 6 and 12 months for all patients. Wound edge necrosis was seen in 2 cases (1.9%), and soft tissue infection was observed in 1 case (0.9%). Böhler angle improved from 7.3 degree preoperatively to 28.7 degree at 6 months. The posterior facet step-off was reduced from 5.3 mm preoperatively to 0.7 mm postoperatively. The average AOFAS score averaged 89.5 at 6-month and 92.6 at 12-month follow-up. The C-Nail is a new locking system for treatment of displaced

  5. Comparisons of external fixator combined with limited internal fixation and open reduction and internal fixation for Sanders type 2 calcaneal fractures: Finite element analysis and clinical outcome.

    PubMed

    Pan, M; Chai, L; Xue, F; Ding, L; Tang, G; Lv, B

    2017-07-01

    The aim of this study was to compare the biomechanical stability and clinical outcome of external fixator combined with limited internal fixation (EFLIF) and open reduction and internal fixation (ORIF) in treating Sanders type 2 calcaneal fractures. Two types of fixation systems were selected for finite element analysis and a dual cohort study. Two fixation systems were simulated to fix the fracture in a finite element model. The relative displacement and stress distribution were analysed and compared. A total of 71 consecutive patients with closed Sanders type 2 calcaneal fractures were enrolled and divided into two groups according to the treatment to which they chose: the EFLIF group and the ORIF group. The radiological and clinical outcomes were evaluated and compared. The relative displacement of the EFLIF was less than that of the plate (0.1363 mm to 0.1808 mm). The highest von Mises stress value on the plate was 33% higher than that on the EFLIF. A normal restoration of the Böhler angle was achieved in both groups. No significant difference was found in the clinical outcome on the American Orthopedic Foot and Ankle Society Ankle Hindfoot Scale, or on the Visual Analogue Scale between the two groups (p > 0.05). Wound complications were more common in those who were treated with ORIF (p = 0.028). Both EFLIF and ORIF systems were tested to 160 N without failure, showing the new construct to be mechanically safe to use. Both EFLIF and ORIF could be effective in treating Sanders type 2 calcaneal fractures. The EFLIF may be superior to ORIF in achieving biomechanical stability and less blood loss, shorter surgical time and hospital stay, and fewer wound complications. Cite this article : M. Pan, L. Chai, F. Xue, L. Ding, G. Tang, B. Lv. Comparisons of external fixator combined with limited internal fixation and open reduction and internal fixation for Sanders type 2 calcaneal fractures: Finite element analysis and clinical outcome. Bone Joint Res 2017

  6. Minimally invasive reduction and fixation of displaced calcaneal fractures: surgical technique and radiographic analysis.

    PubMed

    Arastu, Mateen; Sheehan, Brendan; Buckley, Richard

    2014-03-01

    The optimal treatment of calcaneal fractures is controversial. A specific subgroup of healthy patients has good outcomes with open reduction and internal fixation using an extensile lateral approach. However, there are many patients who do not fit into this category. Consequently, they are either denied surgical intervention or put at significant risk of developing complications as a result of open surgical intervention. Minimally invasive reduction and fixation (MIRF) of calcaneal fractures can restore the height, width, length and shape of the hindfoot in addition to restoring the orientation of the posterior facet of the calcaneus (Böhler's angle). We present a series of 31 patients treated with minimally invasive reduction and fixation technique using threaded K wires and Steinmann pins as an alternative treatment method in patients who are not suitable for open reduction and internal fixation. The mean time to surgery from injury was six days (range one to ten days). The mean duration of surgery was 35 minutes (range 11-52 minutes). The mean followup was 14.9 months (range of seven to 30 months). The mean change in Böhler's angle and length of the calcaneus from intra-operative fixation to final followup were 18.7° and 4.7 mm, respectively. The complication rate was low and there was one case of a superficial wound infection and no cases of deep infection or peroneal impingement in this series. The MIRF technique with the use of threaded K wires has not been previously described in the literature. In our experience, the operative time is short and can be safely performed even in the presence of extensive soft tissue swelling in the immediate period following injury. The infection risk is low and calcaneal morphology was improved and maintained in terms of Böhler's angle. This technique is suitable to be considered in patients who have significant medical co-morbidities (smokers, diabetics, peripheral vascular disease) and in those patients who are

  7. Functional outcome following tibio-talar-calcaneal nailing for unstable osteoporotic ankle fractures.

    PubMed

    Jonas, S C; Young, A F; Curwen, C H; McCann, P A

    2013-07-01

    Fragility fractures of the ankle are increasing in incidence. Such fractures typically occur from low-energy injuries but lead to disproportionately high levels of morbidity. Ankle fractures in this age group are managed conservatively in plaster or by open reduction and internal fixation. Both modalities have shown high rates of failure in terms of delayed union or mal-union together with perioperative complications such as implant failure and wound breakdown. The optimal treatment of these patients remains controversial. We aimed to review the functional outcome of patients with ankle fragility fractures primarily managed using a tibio-talar-calcaneal nail (TTC). We retrospectively reviewed 31 consecutive patients primarily managed with a TCC nail for osteoporotic fragility fractures about the ankle. Data were collected via case notes, radiographic reviews and by clinical reviews at the outpatient clinic or a telephone follow-up. Information regarding patient characteristics, indication for operation, Arbeitsgemeinschaft für Osteosynthesefragen (AO) fracture classification, operative and postoperative complications, time to radiographic union and current clinical state including Olerud and Molander scores were recorded (as a measure of ankle function). Nine of 31 patients had died by the time of follow-up. Mean preoperative and postoperative Olerud and Molander scores were 56 and 45, respectively. There were no postoperative wound complications. Twenty-nine of 31 patients returned to the same level of mobility as pre-injury. There were three peri-prosthetic fractures managed successfully with nail removal and replacement or plaster cast. There were two nail failures, both in patients who mobilised using only a stick, which were managed by nail removal. Ten of 31 patients were not followed up radiographically due to either infirmity or death. Thirteen of 21 followed up radiographically had evidence of union and 8/21 had none. None, however, had clinical evidence

  8. [Treatment of calcaneal fractures using the medial approach for open reduction].

    PubMed

    Vanĕcek, L; Malkus, T; Dungl, P

    2003-01-01

    A comprehensive evaluation of the treatment of calcaneal fractures by open reduction is presented. The long-term results are compared with the relevant literature data. In the period from 1987 to 2000, 60 displaced fractures of the calcaneus were treated in 51 patients. Of these, 49 patients suffered the fracture by falling from a height, which is generally the most common cause. Only two patients were injured during sports activities. Thirty eight injuries were classified as fractures of the joint depression type and 22 as fractures of the tongue type. The patients had surgery on the day they sustained the injury or after edema had subsided, if this was present on admission. The interval between injury and surgery was 4.6 days on the average. The fracture was fixed with Kirschner's wires (Kw) in 53 cases, a Kirshcner's wire and a hook-nail in five cases and a Kirchner's wire and a spongious screw in two patients. In May 2001, 23 patients were available for evaluation after a follow-up period of 6 to 120 months. The patients underwent clinical and radiographic examination and filled a questionnaire. The fracture type was defined on the basis of the Essex-Lopresti classification system. Outcomes were scored according to the Creighton-Nebraska Health Foundation rating system that assessed pain, range of motion, edema, a change in shoe size, patient's activity after therapy termination and return to a job. In May 2001, 23 patients, with a follow-up ranging from 6 to 120 months were checked up. Of them, 20 (86.9%) had neither clinical manifestations nor subjective complaints. Three patients retired because of persisting complaints, two with disability pensions and one with an old-age pension. A total of 19 patients were evaluated by the Creighton-Nebraska Health Foundation rating system. The average score was 90.8 points. The results were excellent in 15 patients, good in three and poor in one patient. The complications reported by the patients included superficial

  9. Post-traumatic in situ fusion after calcaneal fractures: a retrospective study with 7-28 years follow-up.

    PubMed

    Ågren, Per-Henrik; Tullberg, Tycho; Mukka, Sebastian; Wretenberg, Per; Sayed-Noor, Arkan S

    2015-03-01

    In situ fusion as salvage operation after calcaneal fractures has been used. In this retrospective investigation, a group of in situ fused patients is analyzed with long-term follow-up. Twenty-nine patients with in situ single or multiple fusions performed between 1970 and 1990 were included. In 1998 these patients were examined with plain radiographs and computerized tomography (CT) scan of the affected foot. Also, a visual analogue score (VAS) for calcaneal fractures, short form health survey (SF-36), Olerud Molander score and American Orthopaedic Foot and Ankle society (AOFAS) hindfoot score were evaluated. The plain radiographs and CT scan showed severe remaining deformities in these patients. The outcome parameters were generally poor and correlated to the degree of remaining deformity. Simple in situ fusion, without consideration of the deformity at hand, after a calcaneal fracture is not an adequate treatment and generally associated with poor outcome. Copyright © 2014 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

  10. Comparison of the Conventional Surgery and the Surgery Assisted by 3d Printing Technology in the Treatment of Calcaneal Fractures.

    PubMed

    Zheng, Wenhao; Tao, Zhenyu; Lou, Yiting; Feng, Zhenhua; Li, Hang; Cheng, Liang; Zhang, Hui; Wang, Jianshun; Guo, Xiaoshan; Chen, Hua

    2017-09-19

    This study was aimed to compare conventional surgery and surgery assisted by 3D printing technology in the treatment of calcaneal fractures. In addition, we also investigated the effect of 3D printing technology on the communication between doctors and patients. we enrolled 75 patients with calcaneal fracture from April 2014 to August 2016. They were divided randomly into two groups: 35 cases of 3D printing group, 40 cases of conventional group. The individual models were used to simulate the surgical procedures and carry out the surgery according to plan in 3D printing group. Operation duration, blood loss volume during the surgery, number of intraoperative fluoroscopy and fracture union time were recorded. The radiographic outcomes Böhler angle, Gissane angle, calcaneal width and calcaneal height and final functional outcomes including VAS and AOFAS score as well as the complications were also evaluated. Besides, we made a simple questionnaire to verify the effectiveness of the 3D-printed model for both doctors and patients. The operation duration, blood loss volume and number of intraoperative fluoroscopy for 3D printing group was 71.4 ± 6.8 minutes, 226.1 ± 22.6 ml and 5.6 ± 1.9 times, and for conventional group was 91.3 ± 11.2 minutes, 288.7 ± 34.8 ml and 8.6 ± 2.7 times respectively. There was statistically significant difference between the conventional group and 3D printing group (p < 0.05). Additionally, 3D printing group achieved significantly better radiographic results than conventional group both postoperatively and at the final follow-up (p < 0.05). However, No significant difference was noted in the final functional outcomes between the two groups. As for complications, there was no significant difference between the two groups. Furthermore, the questionnaire showed that both doctors and patients exhibited high scores of overall satisfaction with the use of a 3D printing model. This study suggested the clinical feasibility of 3D printing

  11. Patient satisfaction after open reduction and internal fixation through lateral extensile approach in displaced intraarticular calcaneal fractures (Sander's type II and III).

    PubMed

    Kavin, Khatri; Vijay, Sharma; Devendra, Lakhotia; Kamran, Farooque

    2016-01-01

    To determine patient satisfaction in the patients of displaced intraarticular calcaneal fractures treated with standard lateral approach. The patients of displaced calcaneal fractures (Sander's type II and III) treated between March 2009 and March 2012 were included in the retrospective review and functional outcome was evaluated using American Orthopaedic Foot and Ankle Society (AOFAS) hind foot score, Creighton Nebraska Health Foundation Assessment (CNHFA) scale and foot function index (FFI). The cohort included 26 patients (19 males: seven were females) with a mean age of 38.16 ± 13.53 years (range 18-64 years). The mean period of follow-up was 24.42 ± 6.68 months. The patients achieved good functional scores after anatomical reduction of the fracture. The complication rate was low following strict inclusion criteria. Careful patient selection in displaced intraarticular calcaneal fractures treated through lateral extensile approach achieves good patient satisfaction.

  12. Treatment of displaced intra-articular calcaneal fractures with triangular tube-to-bar external fixation: long-term clinical follow-up and radiographic analysis.

    PubMed

    Roukis, Thomas S; Wünschel, Markus; Lutz, Hans-Peter; Kirschner, Peter; Zgonis, Thomas

    2008-04-01

    Sixty-six feet (62 patients) with displaced intra-articular calcaneal fractures underwent manual reduction and distraction with the use of a triangular tube-to-bar external fixation device and were retrospectively reviewed at a minimum of 1-year post-operative. Final radiographic follow-up revealed complete consolidation in all fractures, maintenance of reduction, and limited degenerative osteoarthrosis about the subtalar joint. Our results indicate that with proper application and attention to detail, restoration of calcaneal morphology using triangular tube-to-bar external fixation should be considered a viable alternative in the treatment of displaced intra-articular fractures of the calcaneus.

  13. Metatarsal stress fractures - aftercare

    MedlinePlus

    ... page: //medlineplus.gov/ency/patientinstructions/000553.htm Metatarsal stress fractures - aftercare To use the sharing features on ... that connect your ankle to your toes. A stress fracture is a break in the bone that ...

  14. Altered-stress fracturing

    SciT

    Warpinski, N.R.; Branagan, P.T.

    Altered-stress fracturing is a concept whereby a hydraulic fracture in one well is reoriented by another hydraulic fracture in a nearby location. The application is in tight, naturally fractured, anisotropic reservoirs in which conventional hydraulic fractures parallel the highly permeable natural fractures and little production enhancement is achieved by conventional hydraulic fracturing. Altered-stress fracturing can modify the stress field so that hydraulic fractures propagate across the permeable natural fractures. A field test was conducted in which stress changes of 250 to 300 psi (1.7 to 2.1 MPa) were measured in an offset well 120 ft (37 m) away during relativelymore » small minifracs in a production well. These results show that stress-altered fracturing is possible at this site and others. Analytic and finite element calculations quantify the effects of layers, stresses, and crack size. Reservoir calculations show significant enhancement compared to conventional treatments. 21 refs., 12 figs., 3 tabs.« less

  15. Intra-articular calcaneal fractures: effect of open reduction and internal fixation on the contact characteristics of the subtalar joint.

    PubMed

    Mulcahy, D M; McCormack, D M; Stephens, M M

    1998-12-01

    Intra-articular calcaneal fractures are associated with significant long-term morbidity, and considerable controversy exists regarding the optimum method of treating them. The contact characteristics in the intact subtalar joint were determined at known loads and for different positions of the ankle and subtalar joint, using pressure-sensitive film (Super Low; Fuji, Itochu Canada Ltd, Montreal, Quebec). We measured the contact area to joint area ratio (pressure > 5 kg force/cm2 [kgf/cm2]) which normalizes for differences in joint size and the ratio of high pressure zone (>20 kgf/cm2) as a reflection of overall increase in joint pressure. Three simulated fracture patterns were then created and stabilized with either 1 or 2 mm of articular incongruity. Eight specimens were prepared with a primary fracture line through the posterior facet, eight with a joint depression-type fracture, and six with a central joint depression fracture. A measure of 1 to 2 mm of incongruity in the posterior facet for all three fracture patterns produced significant unloading of the depressed fragment, with a redistribution of the overall pattern of pressure distribution to parts of the facet that were previously unloaded.

  16. Percutaneous reduction and fixation of an intra-articular calcaneal fracture using an inflatable bone tamp: description of a novel and safe technique

    PubMed Central

    2012-01-01

    Calcaneal fractures are common injuries involving the hind foot and often a source of significant long-term morbidity. Treatment options have changed throughout the ages from periods of preferred nonoperative management to closed reduction with a mallet, and more recently, open reduction and anatomic internal fixation. The current treatment of choice; however, is often debated, as open management of these fractures carries many risks to include wound breakdown and infection. A less invasive form of surgical management through small incisions, while maintaining the ability to obtain joint congruency, anatomic alignment, and restore calcaneal height and width would be ideal. We propose a novel form of fracture reduction using an inflatable bone tamp and percutaneous fracture fixation. Preoperative planning and experienced fluoroscopy is crucial to successful management using this method. Although we achieved successful radiographic outcome in this case, long-term functional outcome of this technique are yet to be published. PMID:22420710

  17. Effects of intra-operative fluoroscopic 3D-imaging on peri-operative imaging strategy in calcaneal fracture surgery.

    PubMed

    Beerekamp, M S H; Backes, M; Schep, N W L; Ubbink, D T; Luitse, J S; Schepers, T; Goslings, J C

    2017-12-01

    Previous studies demonstrated that intra-operative fluoroscopic 3D-imaging (3D-imaging) in calcaneal fracture surgery is promising to prevent revision surgery and save costs. However, these studies limited their focus to corrections performed after 3D-imaging, thereby neglecting corrections after intra-operative fluoroscopic 2D-imaging (2D-imaging). The aim of this study was to assess the effects of additional 3D-imaging on intra-operative corrections, peri-operative imaging used, and patient-relevant outcomes compared to 2D-imaging alone. In this before-after study, data of adult patients who underwent open reduction and internal fixation (ORIF) of a calcaneal fracture between 2000 and 2014 in our level-I Trauma center were collected. 3D-imaging (BV Pulsera with 3D-RX, Philips Healthcare, Best, The Netherlands) was available as of 2007 at the surgeons' discretion. Patient and fracture characteristics, peri-operative imaging, intra-operative corrections and patient-relevant outcomes were collected from the hospital databases. Patients in whom additional 3D-imaging was applied were compared to those undergoing 2D-imaging alone. A total of 231 patients were included of whom 107 (46%) were operated with the use of 3D-imaging. No significant differences were found in baseline characteristics. The median duration of surgery was significantly longer when using 3D-imaging (2:08 vs. 1:54 h; p = 0.002). Corrections after additional 3D-imaging were performed in 53% of the patients. However, significantly fewer corrections were made after 2D-imaging when 3D-imaging was available (Risk difference (RD) -15%; 95% Confidence interval (CI) -29 to -2). Peri-operative imaging, besides intra-operative 3D-imaging, and patient-relevant outcomes were similar between groups. Intra-operative 3D-imaging provides additional information resulting in additional corrections. Moreover, 3D-imaging probably changed the surgeons' attitude to rely more on 3D-imaging, hence a 15%-decrease of

  18. The utility of dual-energy X-ray absorptiometry, calcaneal quantitative ultrasound, and fracture risk indices (FRAX® and Osteoporosis Risk Assessment Instrument) for the identification of women with distal forearm or hip fractures: A pilot study.

    PubMed

    Esmaeilzadeh, Sina; Cesme, Fatih; Oral, Aydan; Yaliman, Ayse; Sindel, Dilsad

    2016-08-01

    Dual-energy X-ray absorptiometry (DXA) is considered the "gold standard" in predicting osteoporotic fractures. Calcaneal quantitative ultrasound (QUS) variables are also known to predict fractures. Fracture risk assessment tools may also guide us for the detection of individuals at high risk for fractures. The aim of this case-control study was to evaluate the utility of DXA bone mineral density (BMD), calcaneal QUS parameters, FRAX® (Fracture Risk Assessment Tool), and Osteoporosis Risk Assessment Instrument (ORAI) for the discrimination of women with distal forearm or hip fractures. This case-control study included 20 women with a distal forearm fracture and 18 women with a hip fracture as cases and 76 age-matched women served as controls. BMD at the spine, proximal femur, and radius was measured using DXA and acoustic parameters of bone were obtained using a calcaneal QUS device. FRAX® 10-year probability of fracture and ORAI scores were also calculated in all participants. Receiver operating characteristic (ROC) analysis was used to assess fracture discriminatory power of all the tools. While all DXA BMD, and QUS variables and FRAX® fracture probabilities demonstrated significant areas under the ROC curves for the discrimination of hip-fractured women and those without, only 33% radius BMD, broadband ultrasound attenuation (BUA), and FRAX® major osteoporotic fracture probability calculated without BMD showed significant discriminatory power for distal forearm fractures. It can be concluded that QUS variables, particularly BUA, and FRAX® major osteoporotic fracture probability without BMD are good candidates for the identification of both hip and distal forearm fractures.

  19. Clinical Comparison of Extensile Lateral Approach and Sinus Tarsi Approach Combined with Medial Distraction Technique for Intra-Articular Calcaneal Fractures.

    PubMed

    Zhou, Hai-Chao; Yu, Tao; Ren, Hao-Yang; Li, Bing; Chen, Kai; Zhao, You-Guang; Yang, Yun-Feng

    2017-02-01

    To study and compare the clinical outcomes of open reduction and internal fixation via extensile L-shape incision and limited open reduction via the sinus tarsi approach using the medial distraction technique for intra-articular calcaneal fractures. We performed a retrospective review of 65 intra-articular calcaneal fractures treated operatively between March 2012 and February 2015. Patients were divided into two groups: 28 were in the sinus tarsi approach group and 37 were in the extensile lateral approach group. All patients were asked to return for a research visit that included radiography and clinical evaluation. The postoperative function was evaluated using the ankle and hindfoot score of the American Orthopaedic Foot and Ankle Society (AOFAS) and the visual analogue scale (VAS). No significant difference was found in demographics between the two groups. The corrected value of the calcaneal varus angle between the two groups is statistically significant (P < 0.05). The overall wound complication rate was 3.6% in the minimally invasive group versus 13.5% in the extensile group. Four patients in the extensile lateral approach group had developed hindfoot varus deformity at last follow-up. At the last follow-up, the average AOFAS ankle and the hindfoot score of the minimal group was 88.4 ± 6.6, and the VAS score was 1.9 ± 0.7, while that of the extensile lateral approach group was 83.2 ± 5.6 and 2.3 ± 1.0, respectively. Limited open reduction via the sinus tarsi approach for intra-articular calcaneal fractures could reduce the incidence of wound complications effectively, and the medial distraction technique is helpful for correcting the calcaneus varus deformity. © 2017 Chinese Orthopaedic Association and John Wiley & Sons Australia, Ltd.

  20. [Calcaneal fractures treated by open reduction and internal fixation with a locking compression plate (LCP). A prospective study. part I: basic analysis of the group].

    PubMed

    Svatoš, F; Bartoška, R; Skála-Rosenbaum, J; Douša, P; Pacovský, V; Krbec, M

    2011-01-01

    In a prospective study of patients with calcaneal fractures treated by open reduction from an extensile lateral approach and LCP osteosynthesis, the authors evaluated the basic epidemiological data, mechanism of injury, type of fracture, essential data on surgery, days of hospital stay and the number of complications. In the period from September 1, 2006 to July 31, 2010, a total of 230 patients with 243 calcaneal fractures were treated. The fractures were classified as either open or closed and according to the Essex-Lopresti system. Of the total number of patients, 135 (55.6 % of all fractures) were indicated for conservative treatment and 108 (44.4% of all fractures) for surgical intervention. Indications for surgery based on the generally accepted criteria enabled us to select 77 patients with 82 fractures (33.7 % of all fractures) for treatment by the method of open reduction and LCP osteosynthesis. These patients constituted the group evaluated here. The other patients were treated using other techniques (21 fractures, i.e., 8.6 % of all fractures, by the Stehlík-Štulík transfixation method and further five [2.1 %] by screw osteosynthesis). Six surgeons were involved in the treatment of this group. For the diagnosis of fractures, plain radiographs in lateral and axial projection and axial and coronal CT images were used. All fractures were treated after subsidence of oedema by the method of open reduction and LCP fixation from an extensile lateral approach, with the use of a tourniquet. The follow-up period for the evaluation of functional outcome and bone union was 3 to 48 months. Fifty patients were followed up for over one year. The group evaluated comprised 58 men (75.3 %) with 63 fractures (76.8 %) and 19 women (24.7 %) with 19 fractures (23.2 %). The average age of the group was 42 years, with 41 years (range, 22-61 years) in men and 47 years (range, 30-70 years) in women. The most frequent cause of injury was a fall from a height below 1 metre and

  1. Bohler's angle's role in assessing the injury severity and functional outcome of internal fixation for displaced intra-articular calcaneal fractures: a retrospective study.

    PubMed

    Su, Yanling; Chen, Wei; Zhang, Tao; Wu, Xingwang; Wu, Zhanpo; Zhang, Yingze

    2013-09-24

    Controversy exits over the role of Böhler's angle in assessing the injury severity of displaced intra-articular calcaneal fractures and predicting the functional outcome following internal fixation. This study aims to investigate whether a correlation exists between Böhler's angle and the injury severity of displaced calcaneal fractures, and between surgical improvement of Böhler's angle and functional outcome. Patients treated operatively for unilateral closed displaced intra-articular calcaneal fractures from January 1, 2004 to March 31, 2008 were identified. The Böhler's angles of both calcaneus were measured, and the measurement of the uninjured foot was used as its normal control. The difference in the value of Böhler's angle measured preoperatively or postoperatively between the angle of the injured foot and that of the contralateral calcaneus were calculated, respectively. The change in Böhler's angle by ratio was calculated by dividing the difference value of Böhler's angle between bilateral calcaneus by its normal control. The injury severity was assessed according to Sanders classification. The functional outcomes were assessed using American Orthopaedic Foot & Ankle Society hindfoot scores. 274 patients were included into the study with a mean follow-up duration of 71 months. According to Sanders classification, the fracture pattern included 105 type II, 121 type III and 48 type IV fractures. According to American Orthopaedic Foot & Ankle Society hindfoot scoring system, the excellent, good, fair and poor results were achieved in 104, 132, 27, and 11 patients, respectively. The preoperative Böhler's angle, difference value of Böhler's angle between bilateral calcaneus, and change in Böhler's angle by ratio each has a significant correlation with Sanders classification (rs=-0.178, P=0.003; rs=-0.174, P=0.004; rs=-0.172, P=0.005, respectively), however, is not correlated with functional outcome individually. The three postoperative measurements

  2. Computed tomography of calcaneal fractures: anatomy, pathology, dosimetry, and clinical relevance

    SciT

    Guyer, B.H.; Levinsohn, E.M.; Fredrickson, B.E.

    1985-11-01

    Eighteen CT examinations were performed in 10 patients for the evaluation of acute intraarticular fractures and their follow-up. Fractures comparable to those in the patients were created in cadavers. The normal anatomy and the traumatically altered anatomy of the calcaneus in the axial, coronal, and sagittal planes are demonstrated by CT and corresponding anatomic sections. Scanning was performed in the axial plane, with subsequent reconstruction in the coronal and sagittal planes. The axial scans show disruption of the inferior part of the posterior facet, calcaneocuboid joint involvement, and widening of the calcaneus. The coronal scans show disruption of the superiormore » part of the posterior facet, sustentaculum tali depression (involvement of middle and anterior facets), peroneal and flexor hallucis longus tendon impingement, and widening and height loss of the calcaneus. The sagittal scans show disruption of the posterior facet, calcaneocuboid joint involvement, and height loss of the calcaneus and allow the evaluation of Boehler's and Gissane's angles. All three planes show the position of major fracture fragments. Radiation dose to the foot was measured to be 0.1 rad (0.001 Gy) for plain film radiography (five exposures), 18 rad (0.18 Gy) for conventional tomography (20 cuts), and 2.6 rad (0.026 Gy) for axial CT examination.« less

  3. Reduction and internal fixation of displaced intra-articular calcaneal fractures with a locking nail: a prospective study of sixty nine cases.

    PubMed

    Simon, P; Goldzak, M; Eschler, A; Mittlmeier, T

    2015-10-01

    The best treatment for intra-articular fractures of the calcaneus is still debated. The aims of this study were to determine whether intrafocal reduction of thalamic fractures is effective, to evaluate whether a locking nail is able to maintain reduction of the articular surface and to analyse the functional results of this original method. This prospective study assessed 69 fractures treated with a locking fracture nail in 63 cases and with primary subtalar fusion in six (Calcanail (®), FH). Articular congruity and global reduction of the calcaneus was assessed in all patients by computed tomography (CT) scan three months postoperatively. Functional results were evaluated according to the American Orthopaedic Foot and Ankle Society Ankle-Hindfoot Score (AOFAS-AHS) and all complications recorded. For the 63 fracture nails, the average AOFAS score was 85.9 at a mean final follow-up of 12 months. Only three secondary fusions were performed. For the six comminuted fractures requiring primary fusion, the average AOFAS score was 75.9 at the last follow-up. The posterior intrafocal approach for both reduction and locked nailing of intra-articular calcaneal fractures has been proven as an effective and reliable procedure.

  4. Risk factors for stress fractures.

    PubMed

    Bennell, K; Matheson, G; Meeuwisse, W; Brukner, P

    1999-08-01

    Preventing stress fractures requires knowledge of the risk factors that predispose to this injury. The aetiology of stress fractures is multifactorial, but methodological limitations and expediency often lead to research study designs that evaluate individual risk factors. Intrinsic risk factors include mechanical factors such as bone density, skeletal alignment and body size and composition, physiological factors such as bone turnover rate, flexibility, and muscular strength and endurance, as well as hormonal and nutritional factors. Extrinsic risk factors include mechanical factors such as surface, footwear and external loading as well as physical training parameters. Psychological traits may also play a role in increasing stress fracture risk. Equally important to these types of analyses of individual risk factors is the integration of information to produce a composite picture of risk. The purpose of this paper is to critically appraise the existing literature by evaluating study design and quality, in order to provide a current synopsis of the known scientific information related to stress fracture risk factors. The literature is not fully complete with well conducted studies on this topic, but a great deal of information has accumulated over the past 20 years. Although stress fractures result from repeated loading, the exact contribution of training factors (volume, intensity, surface) has not been clearly established. From what we do know, menstrual disturbances, caloric restriction, lower bone density, muscle weakness and leg length differences are risk factors for stress fracture. Other time-honoured risk factors such as lower extremity alignment have not been shown to be causative even though anecdotal evidence indicates they are likely to play an important role in stress fracture pathogenesis.

  5. Foot and Ankle Stress Fractures in Athletes.

    PubMed

    Greaser, Michael C

    2016-10-01

    The incidence of stress fractures in the general athletic population is less than 1%, but may be as high as 15% in runners. Stress fractures of the foot and ankle account for almost half of bone stress injuries in athletes. These injuries occur because of repetitive submaximal stresses on the bone resulting in microfractures, which may coalesce to form complete fractures. Advanced imaging such as MRI and triple-phase bone scans is used to evaluate patients with suspected stress fracture. Low-risk stress fractures are typically treated with rest and protected weight bearing. High-stress fractures more often require surgical treatment. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. 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.

  7. Tarsal navicular stress fractures: radiographic evaluation

    SciT

    Pavlov, H.; Torg, J.S.; Freiberger, R.H.

    1983-09-01

    Tarsal navicular stress fractures are a potential source of disabling foot pain in physically active individuals. The diagnosis of tarsal navicular stress fracture requires a high index of clinical and radiographic suspicion because the fracture is only rarely evident on routine radiographs or standard tomograms. The radiographic diagnosis of a tarsal navicular stress fracture may require anatomic anteroposterior tomograms or a radionuclide bone scan with plantar views. Radiographic examinations of 23 fractures in 21 patients are evaluated.

  8. Sinus tarsi approach (STA) versus extensile lateral approach (ELA) for treatment of closed displaced intra-articular calcaneal fractures (DIACF): A meta-analysis.

    PubMed

    Bai, L; Hou, Y-L; Lin, G-H; Zhang, X; Liu, G-Q; Yu, B

    2018-04-01

    Our aim was to compare the effect of sinus tarsi approach (STA) vs extensile lateral approach (ELA) for treatment of closed displaced intra-articular calcaneal fractures (DIACF) is still being debated. A thorough research was carried out in the MEDLINE, EMBASE and Cochrane library databases from inception to December 2016. Only prospective or retrospective comparative studies were selected in this meta-analysis. Two independent reviewers conducted literature search, data extraction and quality assessment. The primary outcomes were anatomical restoration and prevalence of complications. Secondary outcomes included operation time and functional recovery. Four randomized controlled trials involving 326 patients and three cohort studies involving 206 patients were included. STA technique for DIACFs led to a decline in both operation time and incidence of complications. There were no significant differences between the groups in American Orthopedic Foot and Ankle Society scores, nor changes in Böhler angle. This meta-analysis suggests that STA technique may reduce the operation time and incidence of complications. In conclusion, STA technique is reasonably an optimal choice for DIACF. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  9. Radiological study of the secondary reduction effect of early functional exercise on displaced intra-articular calcaneal fractures after internal compression fixation.

    PubMed

    Chen, Wei; Liu, Bo; Lv, Hongzhi; Su, Yanling; Chen, Xiao; Zhu, Yanbin; Du, Chenguang; Zhang, Xiaolin; Zhang, Yingze

    2017-09-01

    Early post-operative exercise and weight-bearing activities are found to improve the functional recovery of patients with displaced intra-articular calcaneal fractures (DIACFs). We hypothesized that early functional exercise after surgery might have a secondary reduction effect on the subtalar joint, in particular the smaller fracture fragments that were not fixed firmly. A prospective study was conducted to verify this hypothesis. From December 2012 to September 2013, patients with unilateral DIACFs were enrolled and received a treatment consisting of percutaneous leverage and minimally invasive fixation. After surgery, patients in the study group started exercising on days two to three, using partial weight bearing starting week three, and full weight bearing starting week 12. Patients in the control group followed a conventional post-operative protocol of partial weight bearing after week six and full weight bearing after the bone healed. Computed tomography (CT) scanning was performed at post-operative day one, week four, week eight, and week 12 to reconstruct coronal, sagittal, and axial images, on which the maximal residual displacements of the fractures were measured. Function was evaluated using the American Orthopaedic Foot and Ankle Society (AOFAS) scoring scale at the 12th post-operative month. Twenty-eight patients in the study group and 32 in the control group were followed up for more than 12 months; their data were collected and used for the final analysis. Repeated-measures analysis of variance (ANOVA) of the maximal residual displacements of the fracture measured on CT images revealed significant differences between the study and the control groups. There were interaction effects between group and time point. Except for the first time point, the differences between the groups at all studied time points were significant. In the study group, the differences between all studied time points were significant. Strong correlations were observed between

  10. Differentiating Stress Fracture From Periostitis.

    PubMed

    Martire, J R

    1994-10-01

    In brief Even in the age of high-technology MRI and CT, the triple-phase bone scan (TPBS) remains an exceptionally useful and accurate tool in evaluating athletic injuries. This is perhaps best seen in active people with overuse injuries of the tibia, femur, or humerus when plain films are negative but bone pain persists. Differentiating periostitis from stress fracture requires analyzing distinctive TPBS appearances and patterns.

  11. Plate Fixation With Autogenous Calcaneal Dowel Grafting Proximal Fourth and Fifth Metatarsal Fractures: Technique and Case Series.

    PubMed

    Seidenstricker, Chad L; Blahous, Edward G; Bouché, Richard T; Saxena, Amol

    Metaphyseal and proximal diaphyseal fractures of the lateral column metatarsals can have problems with healing. In particular, those involving the fifth metatarsal have been associated with a high nonunion rate with nonoperative treatment. Although intramedullary screw fixation results in a high union rate, delayed healing and complications can occur. We describe an innovative technique to treat both acute and chronic injuries involving the metatarsal base from the metaphysis to the proximal diaphyseal bone of the fourth and fifth metatarsals. The surgical technique involves evacuation of sclerotic bone at the fracture site, packing the fracture site with compact cancellous bone, and plate fixation. In our preliminary results, 4 patients displayed 100% radiographic union at a mean of 4.75 (range 4 to 6) weeks with no incidence of refracture, at a mean follow-up point of 3.5 (range 1 to 5) years. The early results with our small series suggest that this technique is a useful treatment choice for metaphyseal and proximal diaphyseal fractures of the fourth and fifth metatarsals. Copyright © 2017 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  12. Epidemiology of metatarsal stress fractures versus tibial and femoral stress fractures during elite training.

    PubMed

    Finestone, Aharon; Milgrom, Charles; Wolf, Omer; Petrov, Kaloyan; Evans, Rachel; Moran, Daniel

    2011-01-01

    The training of elite infantry recruits takes a year or more. Stress fractures are known to be endemic in their basic training and the clinical presentation of tibial, femoral, and metatarsal stress fractures are different. Stress fracture incidence during the subsequent progressively more demanding training is not known. The study hypothesis was that after an adaptation period, the incidence of stress fractures during the course of 1 year of elite infantry training would fall in spite of the increasingly demanding training. Seventy-six male elite infantry recruits were followed for the development of stress fractures during a progressively more difficult training program composed of basic training (1 to 14 weeks), advanced training (14 to 26 weeks), and unit training (26 to 52 weeks). Subjects were reviewed regularly and those with clinical suspicion of stress fracture were assessed using bone scan and X-rays. The incidence of stress fractures was 20% during basic training, 14% during advanced training and 23% during unit training. There was a statistically significant difference in the incidence of tibial and femoral stress fractures versus metatarsal stress fractures before and after the completion of phase II training at week 26 (p=0.0001). Seventy-eight percent of the stress fractures during phases I and II training were either tibial or femoral, while 91% of the stress fractures in phase III training were metatarsal. Prior participation in ball sports (p=0.02) and greater tibial length (p=0.05) were protective factors for stress fracture. The study hypothesis that after a period of soldier adaptation, the incidence of stress fractures would decrease in spite of the increasingly demanding elite infantry training was found to be true for tibial and femoral fractures after 6 months of training but not for metatarsal stress fractures. Further studies are required to understand the mechanism of this difference but physicians and others treating stress fractures

  13. Stress fractures: diagnosis, treatment, and prevention.

    PubMed

    Patel, Deepak S; Roth, Matt; Kapil, Neha

    2011-01-01

    Stress fractures are common injuries in athletes and military recruits. These injuries occur more commonly in lower extremities than in upper extremities. Stress fractures should be considered in patients who present with tenderness or edema after a recent increase in activity or repeated activity with limited rest. The differential diagnosis varies based on location, but commonly includes tendinopathy, compartment syndrome, and nerve or artery entrapment syndrome. Medial tibial stress syndrome (shin splints) can be distinguished from tibial stress fractures by diffuse tenderness along the length of the posteromedial tibial shaft and a lack of edema. When stress fracture is suspected, plain radiography should be obtained initially and, if negative, may be repeated after two to three weeks for greater accuracy. If an urgent diagnosis is needed, triple-phase bone scintigraphy or magnetic resonance imaging should be considered. Both modalities have a similar sensitivity, but magnetic resonance imaging has greater specificity. Treatment of stress fractures consists of activity modification, including the use of nonweight-bearing crutches if needed for pain relief. Analgesics are appropriate to relieve pain, and pneumatic bracing can be used to facilitate healing. After the pain is resolved and the examination shows improvement, patients may gradually increase their level of activity. Surgical consultation may be appropriate for patients with stress fractures in high-risk locations, nonunion, or recurrent stress fractures. Prevention of stress fractures has been studied in military personnel, but more research is needed in other populations.

  14. CORRELATION BETWEEN CALCANEAL BONE ULTRASOUND MEASUREMENTS AND DENSITOMETRY AMONG POSTMENOPAUSAL WOMEN WITH FRACTURES CAUSED BY BONE FRAGILITY

    PubMed Central

    Moraes, Frederico Barra; Oliveira, Lindomar Guimarães de; Novais, Pierre de Souza; Melo, Murilo Rodrigues; Guimarães, Mara Lúcia Rassi

    2015-01-01

    Objective: To assess the correlation between ultrasound (US) measurement on the calcaneus and bone densitometry (DEXA), among postmenopausal women who already presented fragility fractures. Methods: 35 postmenopausal women over 40 years of age, with the ability to walk and presenting osteoporotic fractures of the wrist or spine, without previous treatment for osteoporosis, were analyzed in a retrospective cohort. Of these, 16 were under 60 and 19 were over 60. The broadband ultrasound attenuation (BUA) and speed of sound (SOS) were compared using DEXA (L1-L4, total femur, femoral neck and wrist). Two different values of BUA were used as cutoff points for osteoporosis: BUA < 60 dB/MHz and BUA < 64 dB/MHz (P < 0.05); and SOS < 1600 m/s. The confidence interval was 95%. The DEXA and US data were plotted on dispersion graphs and, through linear regression, it was possible to establish correlations. Following this, the sample was stratified according to age (up to 60 years and 60 years and over). Thus, the values were again compared and correlated. Results: The best correlation obtained between DEXA and US was between the T-score of the wrist and BUA < 64 dB/MHz, with 92% sensitivity and 95% specificity. Better sensitivity at all DEXA sites was obtained when US was performed on patients over 60 years of age. The SOS compatible with osteoporosis was < 1592.5 m/s (89% sensitivity and 85% specificity). Conclusion: US on the calcaneus can be used for screening the risk of osteoporosis fractures, using a cutoff of BUA < 64 dB/MHz, especially among patients over 60 years of age. PMID:27027001

  15. CORRELATION BETWEEN CALCANEAL BONE ULTRASOUND MEASUREMENTS AND DENSITOMETRY AMONG POSTMENOPAUSAL WOMEN WITH FRACTURES CAUSED BY BONE FRAGILITY.

    PubMed

    Moraes, Frederico Barra; Oliveira, Lindomar Guimarães de; Novais, Pierre de Souza; Melo, Murilo Rodrigues; Guimarães, Mara Lúcia Rassi

    2011-01-01

    To assess the correlation between ultrasound (US) measurement on the calcaneus and bone densitometry (DEXA), among postmenopausal women who already presented fragility fractures. 35 postmenopausal women over 40 years of age, with the ability to walk and presenting osteoporotic fractures of the wrist or spine, without previous treatment for osteoporosis, were analyzed in a retrospective cohort. Of these, 16 were under 60 and 19 were over 60. The broadband ultrasound attenuation (BUA) and speed of sound (SOS) were compared using DEXA (L1-L4, total femur, femoral neck and wrist). Two different values of BUA were used as cutoff points for osteoporosis: BUA < 60 dB/MHz and BUA < 64 dB/MHz (P < 0.05); and SOS < 1600 m/s. The confidence interval was 95%. The DEXA and US data were plotted on dispersion graphs and, through linear regression, it was possible to establish correlations. Following this, the sample was stratified according to age (up to 60 years and 60 years and over). Thus, the values were again compared and correlated. The best correlation obtained between DEXA and US was between the T-score of the wrist and BUA < 64 dB/MHz, with 92% sensitivity and 95% specificity. Better sensitivity at all DEXA sites was obtained when US was performed on patients over 60 years of age. The SOS compatible with osteoporosis was < 1592.5 m/s (89% sensitivity and 85% specificity). US on the calcaneus can be used for screening the risk of osteoporosis fractures, using a cutoff of BUA < 64 dB/MHz, especially among patients over 60 years of age.

  16. Training, Muscle Fatigue, and Stress Fractures

    DTIC Science & Technology

    1988-07-15

    fractures in the lower appendicular skeleton of new recruits. During peacetime, stress fractures are by far the most co~m~n physical injury in the...research program is to study the etiology of the stress fracture lesion, and isolate any aspects of a physical regime which may exacerbate this...34 of remodelLig, to use the model to identify those areas of the cortex at greatest risk of failure, and the activities which accelerate the deleterious

  17. 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.

  18. Factors associated with recurrent fifth metatarsal stress fracture.

    PubMed

    Lee, Kyung-tai; Park, Young-uk; Jegal, Hyuk; Kim, Ki-chun; Young, Ki-won; Kim, Jin-su

    2013-12-01

    Many surgeons agree that fifth metatarsal stress fractures have a tendency toward delayed union, nonunion, and possibly refracture. Difficulty healing seems to be correlated with fracture classification. However, refracture sometimes occurs after low-grade fracture, even long after apparent resolution. The records of 168 consecutive cases of fifth metatarsal stress fracture (163 patients) treated by modified tension band wiring from March 2002 to June 2011 were evaluated retrospectively. Mean length of follow-up was 23.6 months (range, 10-112 months). Forty-nine cases classified as Torg III were bone grafted initially also. All enrolled patients were elite athletes. Eleven patients experienced nonunion and 18 refracture. The 11 nonunion cases were bone grafted. The 157 patients (excluding nonunion cases) were allocated to either a refracture group or a union group. Clinical features, such as age, weight, fracture classification, time to union, and reinjury history, were compared. Radiological parameters representing cavus deformity and fifth metatarsal head protrusion were compared to evaluate the influence of structural abnormalities. Mean group weights were significantly different (P = .041), but mean ages (P = .879), fracture grades (P = .216, P = .962), and time from surgery to rehabilitation (P = .539) were similar. No significant intergroup differences were found for talocalcaneal (TC) angle (P = .470), calcaneal pitch (CP) angle (P = .847), or talo-first metatarsal (T-MT1) angle (P = .407) on lateral radiographs; for fifth metatarsal lateral deviation (MT5-LD) angle (P = .623) on anteroposterior (AP) radiographs; or for MT5-LD angle (P = .065) on the 30-degree medial oblique radiographs. However, the mean fourth-fifth intermetatarsal (IMA4-5) angle on AP radiographs was significantly greater in the refracture group, and for Torg II cases, mean weight (P = .042), IMA4-5 angle on AP radiographs (P = .014), and MT5-LD angle (P = .043) on 30-degree medial

  19. Transverse Stress Fracture of the Proximal Patella

    PubMed Central

    Atsumi, Satoru; Arai, Yuji; Kato, Ko; Nishimura, Akinobu; Nakazora, Shigeto; Nakagawa, Shuji; Ikoma, Kazuya; Fujiwara, Hiroyoshi; Sudo, Akihiro; Kubo, Toshikazu

    2016-01-01

    Abstract Among stress fractures associated with sports activities, patellar stress fracture is rare. Regarding patella stress fractures, so far only distal transverse or lateral longitudinal fractures have been reported, but there are no reports of transverse fractures occurring in the proximal patella. We describe an extremely rare case of transverse stress fracture of proximal patella in a 9-year-old athlete. A 9-year old boy, who participated in sports (sprints and Kendo) presented with left knee pain without any external injury. In plain radiographs, a fracture line was observed in the proximal 1/3 of the left patella, and a patella stress fracture was diagnosed. For treatment, because 7 months of conservative therapy showed no improvement, internal fixation was carried out using Acutrak screws, and bone union was thus achieved. Three months after the operation, he was able to return to his previous level of athletic sports activity. Regarding the mechanism of onset, it is believed that the causes are longitudinal traction force and patellofemoral contact pressure. On the other hand, the contact region of the patella with the femur changes with the flexion angle of the knee. In the current case, the fracture occurred at a site where the patella was in contact with the femur at a flexion angle of >90°, so it is believed that it occurred as a clinical condition from being subjected to repeated longitudinal traction force and patellofemoral contact pressure at a flexion angle of >90°, during the sports activities of sprints and Kendo. The nonunion of the transverse stress fracture of his proximal patella was successfully treated with internal fixation using Acutrak screws. PMID:26871789

  20. Stress Analysis and Fracture in Nanolaminate Composites

    NASA Technical Reports Server (NTRS)

    Chamis, Christos C.

    2008-01-01

    A stress analysis is performed on a nanolaminate subjected to bending. A composite mechanics computer code that is based on constituent properties and nanoelement formulation is used to evaluate the nanolaminate stresses. The results indicate that the computer code is sufficient for the analysis. The results also show that when a stress concentration is present, the nanolaminate stresses exceed their corresponding matrix-dominated strengths and the nanofiber fracture strength.

  1. Rare stress fracture: longitudinal fracture of the femur.

    PubMed

    Pérez González, M; Velázquez Fragua, P; López Miralles, E; Abad Moretón, M M

    42-year-old man with pain in the posterolateral region of the right knee that began while he was running. Initially, it was diagnosed by magnetic resonance (MR) as a possible aggressive process (osteosarcoma or Ewing's sarcoma) but with computed tomography it was noted a cortical hypodense linear longitudinal image with a continuous, homogeneous and solid periosteal reaction without clear soft tissue mass that in this patient suggest a longitudinal distal femoral fatigue stress fracture. This type of fracture at this location is very rare. Stress fractures are entities that can be confused with an agressive process. MR iscurrently the most sensitive and specific imaging method for its diagnosis. Copyright © 2017 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.

  2. An unusual stress fracture: Bilateral posterior longitudinal stress fracture of tibia.

    PubMed

    Malkoc, Melih; Korkmaz, Ozgur; Ormeci, Tugrul; Oltulu, Ismail; Isyar, Mehmet; Mahirogulları, Mahir

    2014-01-01

    Stress fractures (SF) occur when healthy bone is subjected to cyclic loading, which the normal carrying range capacity is exceeded. Usually, stress fractures occur at the metatarsal bones, calcaneus, proximal or distal tibia and tends to be unilateral. This article presents a 58-year-old male patient with bilateral posterior longitudinal tibial stress fractures. A 58 years old male suffering for persistent left calf pain and decreased walking distance for last one month and after imaging studies posterior longitudinal tibial stress fracture was detected on his left tibia. After six months the patient was admitted to our clinic with the same type of complaints in his right leg. All imaging modalities and blood counts were performed and as a result longitudinal posterior tibial stress fractures were detected on his right tibia. Treatment of tibial stress fracture includes rest and modified activity, followed by a graded return to activity commensurate with bony healing. We have applied the same treatment protocol and our results were acceptable but our follow up time short for this reason our study is restricted for separate stress fractures of the posterior tibia. Although the main localization of tibial stress fractures were unilateral, anterior and transverse pattern, rarely, like in our case, the unusual bilateral posterior localization and longitudinal pattern can be seen. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  3. Thermal stress fracture of ceramic coatings

    NASA Technical Reports Server (NTRS)

    Andersson, C. A.

    1983-01-01

    Thermal stress failures of ceramic coatings are discussed in terms of fracture mechanics concepts. The effects of transient and residual stresses on single and multiple cycle failure mechanisms are considered. A specific example of a zirconia thermal barrier coating is presented and its endurance calculated using the proposed relationships.

  4. Bone stress in runners with tibial stress fracture.

    PubMed

    Meardon, Stacey A; Willson, John D; Gries, Samantha R; Kernozek, Thomas W; Derrick, Timothy R

    2015-11-01

    Combinations of smaller bone geometry and greater applied loads may contribute to tibial stress fracture. We examined tibial bone stress, accounting for geometry and applied loads, in runners with stress fracture. 23 runners with a history of tibial stress fracture & 23 matched controls ran over a force platform while 3-D kinematic and kinetic data were collected. An elliptical model of the distal 1/3 tibia cross section was used to estimate stress at 4 locations (anterior, posterior, medial and lateral). Inner and outer radii for the model were obtained from 2 planar x-ray images. Bone stress differences were assessed using two-factor ANOVA (α=0.05). Key contributors to observed stress differences between groups were examined using stepwise regression. Runners with tibial stress fracture experienced greater anterior tension and posterior compression at the distal tibia. Location, but not group, differences in shear stress were observed. Stepwise regression revealed that anterior-posterior outer diameter of the tibia and the sagittal plane bending moment explained >80% of the variance in anterior and posterior bone stress. Runners with tibial stress fracture displayed greater stress anteriorly and posteriorly at the distal tibia. Elevated tibial stress was associated with smaller bone geometry and greater bending moments about the medial-lateral axis of the tibia. Future research needs to identify key running mechanics associated with the sagittal plane bending moment at the distal tibia as well as to identify ways to improve bone geometry in runners in order to better guide preventative and rehabilitative efforts. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Acoustic Emission Based Surveillance System for Prediction of Stress Fractures

    DTIC Science & Technology

    2007-09-01

    aging are susceptible to such fractures in contexts of osteoporosis, diabetes, cerebral palsy, fibrous dysplasia and osteogenesis imperfecta . This...disease, or, healthy people who have excessive exercise regimes (soldiers and athletes) experience these fractures [2]. Stress fractures interrupt

  6. Calcaneal loading during walking and running

    NASA Technical Reports Server (NTRS)

    Giddings, V. L.; Beaupre, G. S.; Whalen, R. T.; Carter, D. R.

    2000-01-01

    PURPOSE: This study of the foot uses experimentally measured kinematic and kinetic data with a numerical model to evaluate in vivo calcaneal stresses during walking and running. METHODS: External ground reaction forces (GRF) and kinematic data were measured during walking and running using cineradiography and force plate measurements. A contact-coupled finite element model of the foot was developed to assess the forces acting on the calcaneus during gait. RESULTS: We found that the calculated force-time profiles of the joint contact, ligament, and Achilles tendon forces varied with the time-history curve of the moment about the ankle joint. The model predicted peak talocalcaneal and calcaneocuboid joint loads of 5.4 and 4.2 body weights (BW) during walking and 11.1 and 7.9 BW during running. The maximum predicted Achilles tendon forces were 3.9 and 7.7 BW for walking and running. CONCLUSIONS: Large magnitude forces and calcaneal stresses are generated late in the stance phase, with maximum loads occurring at approximately 70% of the stance phase during walking and at approximately 60% of the stance phase during running, for the gait velocities analyzed. The trajectories of the principal stresses, during both walking and running, corresponded to each other and qualitatively to the calcaneal trabecular architecture.

  7. 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.

  8. Olecranon stress fracture in a weight lifter: a case report

    PubMed Central

    Rao, P; Rao, S; Navadgi, B

    2001-01-01

    Stress fractures have been reported in the upper limb of sportspeople involved in upper limb dominated events. Olecranon stress fractures have been cited in baseball pitchers, javelin throwers, and gymnasts. The unusual case of a stress fracture of the olecranon in a young weight lifter is reported here. The minimally displaced stress fracture was treated with tension band and two Kirschner wires. The fracture healed in four months and the patient returned to light sports activity after six months. Key Words: weight lifter; olecranon; elbow; stress fracture PMID:11157469

  9. Biomechanical Factors in Tibial Stress Fractures

    DTIC Science & Technology

    2004-08-01

    these runners. A "stiff’ runner will spend less time in contact with the ground (Farley and Gonzalez, 1996 ) and will attenuate less shock between the...leg and the head (McMahon et al., 1987). This is in agreement with the findings of Farley and Gonzalez ( 1996 ) who suggested lower extremity stiffness...Crossley, K. ( 1996 ) Stress fractures: a review of 180 cases. Clin. J. Sport Med. 6, 85-89. Brudvig, T., Grudger, T. and Obermeyer, L. (1983) Stress

  10. Inelastic and Dynamic Fracture and Stress Analyses

    NASA Technical Reports Server (NTRS)

    Atluri, S. N.

    1984-01-01

    Large deformation inelastic stress analysis and inelastic and dynamic crack propagation research work is summarized. The salient topics of interest in engine structure analysis that are discussed herein include: (1) a path-independent integral (T) in inelastic fracture mechanics, (2) analysis of dynamic crack propagation, (3) generalization of constitutive relations of inelasticity for finite deformations , (4) complementary energy approaches in inelastic analyses, and (5) objectivity of time integration schemes in inelastic stress analysis.

  11. Low Wound Complication Rates for the Lateral Extensile Approach for Calcaneal ORIF When the Lateral Calcaneal Artery Is Patent.

    PubMed

    Bibbo, Christopher; Ehrlich, David A; Nguyen, Hoang M L; Levin, L Scott; Kovach, Stephen J

    2014-07-01

    Historically, the lateral extensile approach for calcaneal fracture osteosynthesis has had relatively high rates of wound healing problems. The vascular territory (angiosome) of the lateral foot is now known to be dependent upon the lateral calcaneal branch of the peroneal artery (LCBP artery). We postulated that patency of the LCBP artery may have a profound positive impact on incisional wound healing for calcaneal open reduction and internal fixation (ORIF). Ninety consecutive calcaneal fractures that met operative criteria were preoperatively evaluated for the presence of a Doppler signal in the LCBP artery and were followed for the development of wound healing problems. Among these 90 fractures, 85 had a positive preoperative Doppler signal along the course of the LCBP artery (94%) and 5 had no Doppler signal (6%). All patients underwent ORIF via a lateral extensile approach. Overall, incisional wound healing problems occurred in 6 of 90 calcaneal incisions (6.5%). All 5 feet that exhibited an absent Doppler signal in the LCPB artery developed an incisional wound healing complication (5/6, approximately 83%): 2 large apical wounds and 3 major dehiscence/slough. However, among the 84 feet that possessed a positive preoperative Doppler signal in the LCBP artery, there was only 1 (1/84, approximately 1%) incisional wound healing problem (P < .0001, Fischer's exact test). Smokers with a positive Doppler signal in the LCBP artery did not develop a wound healing complication. This study suggests a strong link to low incisional wound healing complications for the lateral extensile approach to the calcaneus when a preoperative Doppler signal is present in the LCBP artery. We believe this simple examination should be routinely performed prior to calcaneal ORIF. Level III, comparative case series. © The Author(s) 2014.

  12. Fracture of Rolled Homogeneous Steel Armor (Nucleation Threshold Stress).

    DTIC Science & Technology

    1980-01-01

    AD-AO81 618 ARMY ARMAMENT RESEARCH AND DEVELOPMENT COMMAND ABERD--ETC F/B 19/4 FRACTURE OF ROLLED HOMOGENEOUS STEEL ARMOR (NUCLEATION THRESHOL--ETC(U...ARBRL-MR-02984A QQ FRACTURE OF ROLLED HOMOGENEOUS STEEL ARMOR (NUCLEATION THRESHOLD STRESS) Gerald L Moss Lynn SeamanLy~ S, ,.DTIC S ELECTED January...nucleation stress, Crack threshold stress, Fracture, Fracture stress, Spallation, Armor, Rolled homogeneous steel armor M~ AS$TRACr (Vita ssf -- ebb

  13. Functional outcome of displaced intra-articular calcaneal fractures: a comparison between open reduction/internal fixation and a minimally invasive approach featured an anatomical plate and compression bolts.

    PubMed

    Wu, Zhanpo; Su, Yanling; Chen, Wei; Zhang, Qi; Liu, Yueju; Li, Ming; Wang, Haili; Zhang, Yingze

    2012-09-01

    The purpose of this study is to assess the clinical results of a minimally invasive treatment featured the concept of internal compression, including an anatomic plate and multiple compression bolts compared with open reduction and internal fixation for displaced intra-articular calcaneal fractures (DIACFs). We retrospectively analyzed 329 patients (383 feet) who were identified from trauma inpatient database in our hospital for DIACFs from January 2004 to December 2009. Of them, 148 patients (170 feet) were treated with open reduction and internal fixation (OR group), which involved using a traditional L-shaped extended lateral approach, and fractures were fixed by plate and screws from January 2004 to December 2006; 181 patients (213 feet) were treated with a minimally invasive approach featured the concept of calcaneal internal compression (CIC group), which was achieved by an anatomic plate and multiple compression bolts through a small lateral incision from January 2007 to December 2009. Postoperative complications were recorded. During follow-up, pain and functional outcome were evaluated with the American Orthopaedic Foot and Ankle Society (AOFAS) scores and compared between the two groups. Subsequent subtalar arthrodesis and early implant removal were performed when indicated. Routine hardware removal was scheduled for all patients at 1-year follow-up. There were no significant differences in sex, age, and fracture classification (Sanders classification) between the two groups. Wound healing complications were 4 of 213 (1.88%) in CIC group and 20 of 170 (11.76%) in OR group. Subtalar arthrodesis had to be performed in one case in OR group. Four cases in CIC group and four cases in OR group had the hardware removed earlier due to complications. The average time after surgery to start weight-bearing exercise is 5.64 weeks in CIC group and 9.38 weeks in OR group (p < 0.001). The mean AOFAS score is higher in CIC group than in OR group, although the difference

  14. Fluid Production Induced Stress Analysis Surrounding an Elliptic Fracture

    NASA Astrophysics Data System (ADS)

    Pandit, Harshad Rajendra

    Hydraulic fracturing is an effective technique used in well stimulation to increase petroleum well production. A combination of multi-stage hydraulic fracturing and horizontal drilling has led to the recent boom in shale gas production which has changed the energy landscape of North America. During the fracking process, highly pressurized mixture of water and proppants (sand and chemicals) is injected into to a crack, which fractures the surrounding rock structure and proppants help in keeping the fracture open. Over a longer period, however, these fractures tend to close due to the difference between the compressive stress exerted by the reservoir on the fracture and the fluid pressure inside the fracture. During production, fluid pressure inside the fracture is reduced further which can accelerate the closure of a fracture. In this thesis, we study the stress distribution around a hydraulic fracture caused by fluid production. It is shown that fluid flow can induce a very high hoop stress near the fracture tip. As the pressure gradient increases stress concentration increases. If a fracture is very thin, the flow induced stress along the fracture decreases, but the stress concentration at the fracture tip increases and become unbounded for an infinitely thin fracture. The result from the present study can be used for studying the fracture closure problem, and ultimately this in turn can lead to the development of better proppants so that prolific well production can be sustained for a long period of time.

  15. Couple stresses and the fracture of rock.

    PubMed

    Atkinson, Colin; Coman, Ciprian D; Aldazabal, Javier

    2015-03-28

    An assessment is made here of the role played by the micropolar continuum theory on the cracked Brazilian disc test used for determining rock fracture toughness. By analytically solving the corresponding mixed boundary-value problems and employing singular-perturbation arguments, we provide closed-form expressions for the energy release rate and the corresponding stress-intensity factors for both mode I and mode II loading. These theoretical results are augmented by a set of fracture toughness experiments on both sandstone and marble rocks. It is further shown that the morphology of the fracturing process in our centrally pre-cracked circular samples correlates very well with discrete element simulations. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  16. Stress fractures in elite cross-country athletes.

    PubMed

    Laker, Scott R; Saint-Phard, Deborah; Tyburski, Mark; Van Dorsten, Brent

    2007-04-01

    This retrospective and comparative survey investigates an unusual number of stress fractures seen within a Division I college cross-country team. An anonymous questionnaire-designed to observe factors known to increase stress fracture incidence-was distributed to members of the current and previous seasons' teams. Running surface, sleep hours, intake of calcium, and shoe type were among the factors investigated. Eleven lower extremity stress fractures were found in nine athletes. Athletes with stress fractures reported significantly fewer workouts per week on the new track. All other study parameters had no statistically significant effect on stress fractures in these athletes.

  17. Stress fractures: pathophysiology, clinical presentation, imaging features, and treatment options.

    PubMed

    Matcuk, George R; Mahanty, Scott R; Skalski, Matthew R; Patel, Dakshesh B; White, Eric A; Gottsegen, Christopher J

    2016-08-01

    Stress fracture, in its most inclusive description, includes both fatigue and insufficiency fracture. Fatigue fractures, sometimes equated with the term "stress fractures," are most common in runners and other athletes and typically occur in the lower extremities. These fractures are the result of abnormal, cyclical loading on normal bone leading to local cortical resorption and fracture. Insufficiency fractures are common in elderly populations, secondary to osteoporosis, and are typically located in and around the pelvis. They are a result of normal or traumatic loading on abnormal bone. Subchondral insufficiency fractures of the hip or knee may cause acute pain that may present in the emergency setting. Medial tibial stress syndrome is a type of stress injury of the tibia related to activity and is a clinical syndrome encompassing a range of injuries from stress edema to frank-displaced fracture. Atypical subtrochanteric femoral fracture associated with long-term bisphosphonate therapy is also a recently discovered entity that needs early recognition to prevent progression to a complete fracture. Imaging recommendations for evaluation of stress fractures include initial plain radiographs followed, if necessary, by magnetic resonance imaging (MRI), which is preferred over computed tomography (CT) and bone scintigraphy. Radiographs are the first-line modality and may reveal linear sclerosis and periosteal reaction prior to the development of a frank fracture. MRI is highly sensitive with findings ranging from periosteal edema to bone marrow and intracortical signal abnormality. Additionally, a brief description of relevant clinical management of stress fractures is included.

  18. Effect of Stress State on Fracture Features

    NASA Astrophysics Data System (ADS)

    Das, Arpan

    2018-02-01

    Present article comprehensively explores the influence of specimen thickness on the quantitative estimates of different ductile fractographic features in two dimensions, correlating tensile properties of a reactor pressure vessel steel tested under ambient temperature where the initial crystallographic texture, inclusion content, and their distribution are kept unaltered. It has been investigated that the changes in tensile fracture morphology of these steels are directly attributable to the resulting stress-state history under tension for given specimen dimensions.

  19. Stress Fractures of the Pelvis and Legs in Athletes

    PubMed Central

    Behrens, Steve B.; Deren, Matthew E.; Matson, Andrew; Fadale, Paul D.; Monchik, Keith O.

    2013-01-01

    Context: Stress fractures are common injuries in athletes, often difficult to diagnose. A stress fracture is a fatigue-induced fracture of bone caused by repeated applications of stress over time. Evidence Acquisition: PubMed articles published from 1974 to January 2012. Results: Intrinsic and extrinsic factors may predict the risk of stress fractures in athletes, including bone health, training, nutrition, and biomechanical factors. Based on their location, stress fractures may be categorized as low- or high-risk, depending on the likelihood of the injury developing into a complete fracture. Treatment for these injuries varies substantially and must account for the risk level of the fractured bone, the stage of fracture development, and the needs of the patient. High-risk fractures include the anterior tibia, lateral femoral neck, patella, medial malleolus, and femoral head. Low-risk fractures include the posteromedial tibia, fibula, medial femoral shaft, and pelvis. Magnetic resonance is the imaging test of choice for diagnosis. Conclusions: These injuries can lead to substantial lost time from participation. Treatment will vary by fracture location, but most stress fractures will heal with rest and modified weightbearing. Some may require more aggressive intervention, such as prolonged nonweightbearing movement or surgery. Contributing factors should also be addressed prior to return to sports. PMID:24427386

  20. 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

  1. Stress fracture of the second proximal phalanx of the foot in teenage athletes: Unrecognized location of stress fracture.

    PubMed

    Yamaguchi, Satoshi; Taketomi, Shuji; Funakoshi, Yusei; Tsuchiya, Kan; Akagi, Ryuichiro; Kimura, Seiji; Sadamasu, Aya; Ohtori, Seiji

    2017-10-01

    Adolescent athletes are a high-risk population for stress fractures. We report four cases of stress fractures of the second proximal phalanx, which had not been previously diagnosed as the location of the stress fracture of the foot, in teenage athletes. All fractures were on the plantar side of the proximal phalangeal base, and the oblique images of the plain radiograph clearly depicted the fractures. Notably, three out of the four patients had histories of stress fracture of other locations. While three athletes with acute cases were able to make an early return to play with simple conservative management, the chronic case required surgical treatment for this rare injury. Although a rare injury, it is important that clinicians be aware of this type of stress fracture, as a timely diagnosis can avoid the need for surgical treatment and allow an early return to play.

  2. Impact of Stress on Anomalous Transport in Fractured Rock

    NASA Astrophysics Data System (ADS)

    Kang, P. K.; Lei, Q.; Lee, S.; Dentz, M.; Juanes, R.

    2016-12-01

    Fluid flow and transport in fractured rock controls many natural and engineered processes in the subsurface. However, characterizing flow and transport through fractured media is challenging due to the large heterogeneity of fractured rock properties. In addition to these "static" challenges, geologic fractures are always under significant overburden stress, and changes in the stress state can lead to changes in the fracture's ability to conduct fluids. While confining stress has been shown to impact fluid flow through fractures in a fundamental way, the impact of confining stress on transport through fractured rock remains largely unexplored. The link between anomalous (non-Fickian) transport and confining stress has been shown only recently, at the level of a single rough fracture [1]. Here, we investigate the impact of confining stress on flow and transport through discrete fracture networks. We model geomechanical effects in 2D fractured rock by means of a finite-discrete element method (FEMDEM), which can capture the deformation of matrix blocks, reactivation and propagation of cracks. We implement a joint constitutive model within the FEMDEM framework to simulate the effect of fracture roughness. We apply the model to a fracture network extracted from the geological map of an actual outcrop to obtain the aperture field at different stress conditions (Figure 1). We then simulate fluid flow and particle transport through the stressed fracture networks. We observe that anomalous transport emerges in response to confining stress on the fracture networks, and show that this anomalous behavior can be linked to the stress state of the rock. Finally, we develop an effective transport model that captures the anomalous transport through stressed fractures. Our results point to a heretofore unrecognized link between geomechanics and anomalous transport in discrete fractured networks. [1] P. K. Kang, S. Brown, and R. Juanes, Emergence of anomalous transport in stressed

  3. Role of MRI in hip fractures, including stress fractures, occult fractures, avulsion fractures.

    PubMed

    Nachtrab, O; Cassar-Pullicino, V N; Lalam, R; Tins, B; Tyrrell, P N M; Singh, J

    2012-12-01

    MR imaging plays a vital role in the diagnosis and management of hip fractures in all age groups, in a large spectrum of patient groups spanning the elderly and sporting population. It allows a confident exclusion of fracture, differentiation of bony from soft tissue injury and an early confident detection of fractures. There is a spectrum of MR findings which in part is dictated by the type and cause of the fracture which the radiologist needs to be familiar with. Judicious but prompt utilisation of MR in patients with suspected hip fractures has a positive therapeutic impact with healthcare cost benefits as well as social care benefits. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  4. Fractures and stresses in Bone Spring sandstones

    SciT

    Warpinski, N.R.; Sattler, A.R.; Lorenz, J.C.

    This project was a collaboration between Sandia National Laboratories and the Harvey E. Yates Company (Heyco), Roswell, NM, conducted under the auspices of Department of Energy's Oil Recovery Technology Partnership. The project applied Sandia perspectives on the effects of natural fractures, stress, and sedimentology for the stimulation and production of low permeability gas reservoirs to low permeability oil reservoirs, such as those typified by the Bone Spring sandstones of the Delaware Basin, southeast New Mexico. This report details the results and analyses obtained in 1990 from core, logs, stress, and other data taken from three additional development wells. An overallmore » summary gives results from all five wells studied in this project in 1989--1990. Most of the results presented are believed to be new information for the Bone Spring sandstones.« less

  5. The "safe zone" in medial percutaneous calcaneal pin placement.

    PubMed

    Gamie, Zakareya; Donnelly, Leo; Tsiridis, Eleftherios

    2009-05-01

    Percutaneous pin insertion into the medial calcaneus places a number of structures at risk. Evidence suggests that the greatest risk is to the medial calcaneal nerve (MCN). The medial calcaneal region of 24 cadavers was dissected to determine the major structures at risk. By using four palpable anatomical landmarks, the inferior tip of the medial malleolus (point A), the posterior superior portion of the calcaneal tuberosity (point B), the navicular tuberosity (point C), and the medial process of the calcaneal tuberosity (point D), we attempted to define the safe zone taking into account all possible variables in our dissections including ankle position, side, gender, and possible anatomical variations of the MCN. The commonest arrangement of the MCN was two MCNs that arose independently, one arising before the bifurcation of the tibial nerve and the other arising from the medial plantar nerve. A zone could be defined posterior to 75% of the distance along the lines AB, CD, AD, and CB which would avoid most structures. The posterior branches of the MCN, however, would still be at risk and placing the pin too far posteriorly risks an avulsion fracture. This is the first study to employ four palpable anatomical landmarks to identify a zone to minimize damage to neurovascular structures. It may not be possible, however, to avoid injury of the MCN and consequent sensory loss to the sole of the foot.

  6. Stress fractures of the foot and ankle in athletes.

    PubMed

    Mayer, Stephanie W; Joyner, Patrick W; Almekinders, Louis C; Parekh, Selene G

    2014-11-01

    Stress fractures of the foot and ankle are a common problem encountered by athletes of all levels and ages. These injuries can be difficult to diagnose and may be initially evaluated by all levels of medical personnel. Clinical suspicion should be raised with certain history and physical examination findings. Scientific and review articles were searched through PubMed (1930-2012) with search terms including stress fractures and 1 of the following: foot ankle, medial malleolus, lateral malleolus, calcaneus, talus, metatarsal, cuboid, cuneiform, sesamoid, or athlete. Clinical review. Level 5. Stress fractures of the foot and ankle can be divided into low and high risk based upon their propensity to heal without complication. A wide variety of nonoperative strategies are employed based on the duration of symptoms, type of fracture, and patient factors, such as activity type, desire to return to sport, and compliance. Operative management has proven superior in several high-risk types of stress fractures. Evidence on pharmacotherapy and physiologic therapy such as bone stimulators is evolving. A high index of suspicion for stress fractures is appropriate in many high-risk groups of athletes with lower extremity pain. Proper and timely work-up and treatment is successful in returning these athletes to sport in many cases. Low-risk stress fracture generally requires only activity modification while high-risk stress fracture necessitates more aggressive intervention. The specific treatment of these injuries varies with the location of the stress fracture and the goals of the patient.

  7. Anomalous Transport in Natural Fracture Networks Induced by Tectonic Stress

    NASA Astrophysics Data System (ADS)

    Kang, P. K.; Lei, Q.; Lee, S.; Dentz, M.; Juanes, R.

    2017-12-01

    Fluid flow and transport in fractured rock controls many natural and engineered processes in the subsurface. However, characterizing flow and transport through fractured media is challenging due to the high uncertainty and large heterogeneity associated with fractured rock properties. In addition to these "static" challenges, geologic fractures are always under significant overburden stress, and changes in the stress state can lead to changes in the fracture's ability to conduct fluids. While confining stress has been shown to impact fluid flow through fractures in a fundamental way, the impact of confining stress on transportthrough fractured rock remains poorly understood. The link between anomalous (non-Fickian) transport and confining stress has been shown, only recently, at the level of a single rough fracture [1]. Here, we investigate the impact of geologic (tectonic) stress on flow and tracer transport through natural fracture networks. We model geomechanical effects in 2D fractured rock by means of a finite-discrete element method (FEMDEM) [2], which can capture the deformation of matrix blocks, reactivation of pre-existing fractures, and propagation of new cracks, upon changes in the stress field. We apply the model to a fracture network extracted from the geological map of an actual rock outcrop to obtain the aperture field at different stress conditions. We then simulate fluid flow and particle transport through the stressed fracture networks. We observe that anomalous transport emerges in response to confining stress on the fracture network, and show that the stress state is a powerful determinant of transport behavior: (1) An anisotropic stress state induces preferential flow paths through shear dilation; (2) An increase in geologic stress increases aperture heterogeneity that induces late-time tailing of particle breakthrough curves. Finally, we develop an effective transport model that captures the anomalous transport through the stressed fracture

  8. 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.

  9. Stress fracture of ulna due to excessive push-ups.

    PubMed

    Meena, Sanjay; Rastogi, Devarshi; Solanki, Bipin; Chowdhury, Buddhadev

    2014-01-01

    Stress fractures are most common in the weight-bearing bones of the lower extremities and spine, but are rarely found in non-weight-bearing bones of the body. Stress fracture of the ulna is extremely rare. We report a case of complete stress fracture of ulna caused due to excessive push ups in a young athlete. Conservative management was successful in healing of fracture and returning this patient back to his previous activity level. Physician should have high index of suspicion, whenever they encounter a young athlete complaining of forearm pain.

  10. Spallation and fracture resulting from reflected and intersecting stress waves.

    NASA Technical Reports Server (NTRS)

    Kinslow, R.

    1973-01-01

    Discussion of the effects of stress waves produced in solid by explosions or high-velocity impacts. These waves rebound from free surfaces in the form of tensile waves that are capable of causing internal fractures or spallation of the material. The high-speed framing camera is shown to be an important tool for observing the stress waves and fracture in transparent targets, and its photographs provide valuable information on the mechanics of fracture.

  11. Radiographic Evaluation of Ankle Joint Stability After Calcaneofibular Ligament Elevation During Open Reduction and Internal Fixation of Calcaneus Fracture.

    PubMed

    Wang, Chien-Shun; Tzeng, Yun-Hsuan; Lin, Chun-Cheng; Huang, Ching-Kuei; Chang, Ming-Chau; Chiang, Chao-Ching

    2016-09-01

    The aim of this prospective study was to evaluate the influence of sectioning the calcaneofibular ligament (CFL) during an extensile lateral approach during open reduction and internal fixation (ORIF) of calcaneal fractures on ankle joint stability. Forty-two patients with calcaneal fractures that received ORIF were included. Talar tilt stress and anterior drawer radiographs were performed on the operative and contralateral ankles 6 months postoperatively. The average degree of talar tilt on stress radiographs was 3.4 degrees (range, 0-12 degrees) on the operative side and 3.2 degrees (range, 0-14 degrees) on the contralateral side. The mean anterior drawer on stress radiographs of the CFL incised ankle was 6.1 mm (range, 2.4-11.8 mm) and on the contralateral ankle was 5.7 mm (range, 2.6-8.6 mm). There was no statistically significant difference of talar tilt and anterior drawer between the CFL incised side and the contralateral side (P = .658 and .302, respectively). The results suggest that sectioning of the CFL without any repair during ORIF of a calcaneal fracture does not have a negative effect on stability of the ankle. Repair of the CFL is, thus, probably not necessary following extended lateral approach for ORIF of calcaneal fractures. Level II, comparative study. © The Author(s) 2016.

  12. 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.

  13. Bilateral femoral supracondylar stress fractures in a cross country runner.

    PubMed

    Ross, Kate; Fahey, Mark

    2008-08-01

    Several high-risk factors lead to stress fractures. They include excessive training in athletes leading to overuse injuries, nutritional deficiencies, and endocrine disorders. While stress fractures are common, bilateral stress fractures are rarely seen. Few cases have been reported of bilateral femoral stress fractures in young athletes. This article presents a case of a 14-year-old cross country runner with a bilateral femoral supracondylar stress fracture. He presented with bilateral supracondylar stress fractures from running. The patient followed a strict vegan diet, but his parents stated that, to their knowledge, he was getting adequate protein and calcium. Treatment consisted of decreased activity to pain-free levels with acetaminophen for pain. Low-impact conditioning such as swimming and bicycling was allowed. Hamstring and quadricep stretching was suggested. Nutritional consultation was obtained to ensure appropriate nutrition on a vegan diet. At 1-month follow-up, he was pain free and allowed to proceed with a gradual return to running activities. In this case, the onset of a new workout routine was intolerable for this patient's low bone density, causing insufficiency fractures. Appropriate vegan diets were not associated with stress fracture in our literature review. He may have had an inadequate diet prior to this injury. As in this case, full recovery can be made after this rest period, and the patient may return to his or her original activity safely. In young athletes, diet and nutrition must be kept in mind.

  14. Bilateral femoral neck stress fractures in a fire academy student.

    PubMed

    Wright, Russell C; Salzman, Garrett A; Yacoubian, Stephan V; Yacoubian, Shahan V

    2010-10-11

    Unilateral femoral neck stress fractures are well documented in active patients; however, the risk of a subsequent contralateral stress fracture remains unknown in patients who continue to be active. This article describes a 24-year-old male fire academy student who sustained a left femoral neck stress fracture, followed approximately 11 months later by a right femoral neck stress fracture, both of which went on to completely displace. A review of the index radiographs of each hip from outside institutions revealed femoral neck stress fractures that went undiagnosed until they displaced. The patient was referred to our institution and underwent closed reduction and internal fixation using cannulated screws in both cases. A full endocrine evaluation was performed in the following weeks and proved unremarkable. Although it is difficult to extrapolate the results from 1 patient beyond the case studied, there is cause for concern in patients who remain active following femoral neck stress fractures. Our case highlights the significance of obtaining a complete and thorough medical history on physical examination and appropriately counseling patients regarding activity level. Until further research explores this possible relationship, physicians evaluating patients with a history of a stress fracture are encouraged to be vigilant of subsequent contralateral fractures and educate patients of this potentially avoidable injury. Copyright 2010, SLACK Incorporated.

  15. 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

  16. 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.

  17. Patterns of fracture and tidal stresses due to nonsynchronous rotation - Implications for fracturing on Europa

    NASA Technical Reports Server (NTRS)

    Helfenstein, P.; Parmentier, E. M.

    1985-01-01

    This study considers the global patterns of fracture that would result from nonsynchronous rotation of a tidally distorted planetary body. The incremental horizontal stresses in a thin elastic or viscous shell due to a small displacement of the axis of maximum tidal elongation are derived, and the resulting stress distributions are applied to interpret the observed pattern of fracture lineaments on Europa. The observed pattern of lineaments can be explained by nonsynchronous rotation if these features formed by tension fracturing and dike emplacement. Tension fracturing can occur for a small displacement of the tidal axis, so that the resulting lineaments may be consistent with other evidence suggesting a young age for the surface.

  18. Ultrasound-Diagnosed Tibia Stress Fracture: A Case Report.

    PubMed

    Amoako, Adae; Abid, Ayesha; Shadiack, Anthony; Monaco, Robert

    2017-01-01

    Stress fractures are a frequent cause of lower extremity pain in athletes, and especially in runners. Plain imaging has a low sensitivity. Magnetic resonance imaging (MRI) or bone scan scintigraphy is the criterion standard, but expensive. We present the case of a young female distance runner with left shin pain. Plain radiography was unremarkable. Ultrasound showed focal hyperechoic elevation of the periosteum with irregularity over the distal tibia and increased flow on Doppler. These findings were consistent with a distal tibia stress fracture and confirmed by MRI. Examination of our case will highlight the utility of considering an ultrasound for diagnosis of tibial stress fracture.

  19. Ultrasound-Diagnosed Tibia Stress Fracture: A Case Report

    PubMed Central

    Amoako, Adae; Abid, Ayesha; Shadiack, Anthony; Monaco, Robert

    2017-01-01

    Stress fractures are a frequent cause of lower extremity pain in athletes, and especially in runners. Plain imaging has a low sensitivity. Magnetic resonance imaging (MRI) or bone scan scintigraphy is the criterion standard, but expensive. We present the case of a young female distance runner with left shin pain. Plain radiography was unremarkable. Ultrasound showed focal hyperechoic elevation of the periosteum with irregularity over the distal tibia and increased flow on Doppler. These findings were consistent with a distal tibia stress fracture and confirmed by MRI. Examination of our case will highlight the utility of considering an ultrasound for diagnosis of tibial stress fracture. PMID:28469488

  20. Stress Fractures of the Foot and Ankle in Athletes

    PubMed Central

    Mayer, Stephanie W.; Joyner, Patrick W.; Almekinders, Louis C.; Parekh, Selene G.

    2014-01-01

    Context: Stress fractures of the foot and ankle are a common problem encountered by athletes of all levels and ages. These injuries can be difficult to diagnose and may be initially evaluated by all levels of medical personnel. Clinical suspicion should be raised with certain history and physical examination findings. Evidence Acquisition: Scientific and review articles were searched through PubMed (1930-2012) with search terms including stress fractures and 1 of the following: foot ankle, medial malleolus, lateral malleolus, calcaneus, talus, metatarsal, cuboid, cuneiform, sesamoid, or athlete. Study Design: Clinical review. Level of Evidence: Level 5. Results: Stress fractures of the foot and ankle can be divided into low and high risk based upon their propensity to heal without complication. A wide variety of nonoperative strategies are employed based on the duration of symptoms, type of fracture, and patient factors, such as activity type, desire to return to sport, and compliance. Operative management has proven superior in several high-risk types of stress fractures. Evidence on pharmacotherapy and physiologic therapy such as bone stimulators is evolving. Conclusion: A high index of suspicion for stress fractures is appropriate in many high-risk groups of athletes with lower extremity pain. Proper and timely work-up and treatment is successful in returning these athletes to sport in many cases. Low-risk stress fracture generally requires only activity modification while high-risk stress fracture necessitates more aggressive intervention. The specific treatment of these injuries varies with the location of the stress fracture and the goals of the patient. PMID:25364480

  1. Transverse Stress Fracture of the Proximal Patella: A Case Report.

    PubMed

    Atsumi, Satoru; Arai, Yuji; Kato, Ko; Nishimura, Akinobu; Nakazora, Shigeto; Nakagawa, Shuji; Ikoma, Kazuya; Fujiwara, Hiroyoshi; Sudo, Akihiro; Kubo, Toshikazu

    2016-02-01

    Among stress fractures associated with sports activities, patellar stress fracture is rare. Regarding patella stress fractures, so far only distal transverse or lateral longitudinal fractures have been reported, but there are no reports of transverse fractures occurring in the proximal patella. We describe an extremely rare case of transverse stress fracture of proximal patella in a 9-year-old athlete.A 9-year old boy, who participated in sports (sprints and Kendo) presented with left knee pain without any external injury. In plain radiographs, a fracture line was observed in the proximal 1/3 of the left patella, and a patella stress fracture was diagnosed. For treatment, because 7 months of conservative therapy showed no improvement, internal fixation was carried out using Acutrak screws, and bone union was thus achieved. Three months after the operation, he was able to return to his previous level of athletic sports activity.Regarding the mechanism of onset, it is believed that the causes are longitudinal traction force and patellofemoral contact pressure. On the other hand, the contact region of the patella with the femur changes with the flexion angle of the knee. In the current case, the fracture occurred at a site where the patella was in contact with the femur at a flexion angle of >90°, so it is believed that it occurred as a clinical condition from being subjected to repeated longitudinal traction force and patellofemoral contact pressure at a flexion angle of >90°, during the sports activities of sprints and Kendo. The nonunion of the transverse stress fracture of his proximal patella was successfully treated with internal fixation using Acutrak screws.

  2. Medial malleolar stress fracture secondary to chronic ankle impingement.

    PubMed

    Jowett, Andrew J L; Birks, Christopher L; Blackney, Mark C

    2008-07-01

    Medial malleolar stress fractures are uncommon even in the sporting population. We believe that stress fractures of the medial malleolus may be the end stage of chronic anteromedial ankle impingement in elite running and jumping athletes. We present five cases of elite athletes who presented to our institution with stress fractures of the medial malleolus over a 3-year period (2004 to 2007). In each case preoperative imaging revealed an anteromedial bony spur on the tibia. All fractures were internally fixed and at the same sitting had arthroscopic debridement of the bony spur. All fractures united without further intervention, average time to union was 10.2 (range, 6 to 16) weeks. At most recent review (average, 18 months; range, 8 to 37 months), all patients had resumed sporting activity to their previous level. No patient had suffered a recurrent fracture of the medial malleolus. We believe this region of impingement to be important in the development of the stress fracture and should be addressed at the time of fracture fixation.

  3. Stress Rupture Fracture Model and Microstructure Evolution for Waspaloy

    NASA Astrophysics Data System (ADS)

    Yao, Zhihao; Zhang, Maicang; Dong, Jianxin

    2013-07-01

    Stress rupture behavior and microstructure evolution of nickel-based superalloy Waspaloy specimens from tenon teeth of an as-received 60,000-hour service-exposed gas turbine disk were studied between 923 K and 1088 K (650 °C and 815 °C) under initial applied stresses varying from 150 to 840 MPa. Good microstructure stability and performance were verified for this turbine disk prior to stress rupture testing. Microstructure instability, such as the coarsening and dissolution of γ' precipitates at the varying test conditions, was observed to be increased with temperature and reduced stress. Little microstructure variation was observed at 923 K (650 °C). Only secondary γ' instability occurred at 973 K (700 °C). Four fracture mechanisms were obtained. Transgranular creep fracture was exhibited up to 923 K (650 °C) and at high stress. A mixed mode of transgranular and intergranular creep fracture occurred with reduced stress as a transition to intergranular creep fracture (ICF) at low stress. ICF was dominated by grain boundary sliding at low temperature and by the nucleation and growth of grain boundary cavities due to microstructure instability at high temperature. The fracture mechanism map and microstructure-related fracture model were constructed. Residual lifetime was also evaluated by the Larson-Miller parameter method.

  4. Lower thoracic rib stress fractures in baseball pitchers.

    PubMed

    Gerrie, Brayden J; Harris, Joshua D; Lintner, David M; McCulloch, Patrick C

    2016-01-01

    Stress fractures of the first rib on the dominant throwing side are well-described in baseball pitchers; however, lower thoracic rib fractures are not commonly recognized. While common in other sports such as rowing, there is scant literature on these injuries in baseball. Intercostal muscle strains are commonly diagnosed in baseball pitchers and have a nearly identical presentation but also a highly variable healing time. The diagnosis of a rib stress fracture can predict a more protracted recovery. This case series presents two collegiate baseball pitchers on one team during the same season who were originally diagnosed with intercostal muscle strains, which following magnetic resonance imaging (MRI) were found to have actually sustained lower thoracic rib stress fractures. The first sustained a stress fracture of the posterior aspect of the right 8th rib on the dominant arm side, while the second presented with a left-sided 10th rib stress fracture on the nondominant arm side. In both cases, MRI was used to visualize the fractures as plain radiographs are insensitive and commonly negative early in patient presentation. Patients were treated with activity modification, and symptomatic management for 4-6 weeks with a graduated return to throwing and competition by 8-10 weeks. The repetitive high stresses incurred by pitching may cause either dominant or nondominant rib stress fractures and this should be included in the differential diagnosis of thoracic injuries in throwers. It is especially important that athletic trainers and team physicians consider this diagnosis, as rib fractures may have a protracted course and delayed return to play. Additionally, using the appropriate imaging techniques to establish an accurate diagnosis can help inform return-to-play decisions, which have important practical applications in baseball, such as roster management and eligibility.

  5. Multiple stress fractures in a young female runner.

    PubMed

    Dusek, T; Pećina, M; Loncar-Dusek, M; Bojanic, I

    2004-01-01

    The effect of exercise on female's bone metabolism has received much attention in recent years. We report on unusual case of a female runner with low body mass and amenorrhea, who suffered 4 stress fractures. Three of the stress fractures occurred during her sports career, and the fourth occurred 7 years after the cessation of sports activities. It seems that exercise-induced amenorrhea together with food restriction in the young age may cause long-term consequences on bone metabolism.

  6. Genetic predisposition for femoral neck stress fractures in military conscripts.

    PubMed

    Korvala, Johanna; Hartikka, Heini; Pihlajamäki, Harri; Solovieva, Svetlana; Ruohola, Juha-Petri; Sahi, Timo; Barral, Sandra; Ott, Jürg; Ala-Kokko, Leena; Männikkö, Minna

    2010-10-21

    Stress fractures are a significant problem among athletes and soldiers and may result in devastating complications or even permanent handicap. Genetic factors may increase the risk, but no major susceptibility genes have been identified. The purpose of this study was to search for possible genetic factors predisposing military conscripts to femoral neck stress fractures. Eight genes involved in bone metabolism or pathology (COL1A1, COL1A2, OPG, ESR1, VDR, CTR, LRP5, IL-6) were examined in 72 military conscripts with a femoral neck stress fracture and 120 controls. The risk of femoral neck stress fracture was significantly higher in subjects with low weight and body mass index (BMI). An interaction between the CTR (rs1801197) minor allele C and the VDR C-A haplotype was observed, and subjects lacking the C allele in CTR and/or the C-A haplotype in VDR had a 3-fold higher risk of stress fracture than subjects carrying both (OR = 3.22, 95% CI 1.38-7.49, p = 0.007). In addition, the LRP5 haplotype A-G-G-C alone and in combination with the VDR haplotype C-A was associated with stress fractures through reduced body weight and BMI. Our findings suggest that genetic factors play a role in the development of stress fractures in individuals subjected to heavy exercise and mechanical loading. The present results can be applied to the design of future studies that will further elucidate the genetics of stress fractures.

  7. Genetic predisposition for femoral neck stress fractures in military conscripts

    PubMed Central

    2010-01-01

    Background Stress fractures are a significant problem among athletes and soldiers and may result in devastating complications or even permanent handicap. Genetic factors may increase the risk, but no major susceptibility genes have been identified. The purpose of this study was to search for possible genetic factors predisposing military conscripts to femoral neck stress fractures. Results Eight genes involved in bone metabolism or pathology (COL1A1, COL1A2, OPG, ESR1, VDR, CTR, LRP5, IL-6) were examined in 72 military conscripts with a femoral neck stress fracture and 120 controls. The risk of femoral neck stress fracture was significantly higher in subjects with low weight and body mass index (BMI). An interaction between the CTR (rs1801197) minor allele C and the VDR C-A haplotype was observed, and subjects lacking the C allele in CTR and/or the C-A haplotype in VDR had a 3-fold higher risk of stress fracture than subjects carrying both (OR = 3.22, 95% CI 1.38-7.49, p = 0.007). In addition, the LRP5 haplotype A-G-G-C alone and in combination with the VDR haplotype C-A was associated with stress fractures through reduced body weight and BMI. Conclusions Our findings suggest that genetic factors play a role in the development of stress fractures in individuals subjected to heavy exercise and mechanical loading. The present results can be applied to the design of future studies that will further elucidate the genetics of stress fractures. PMID:20961463

  8. The ICI classification for calcaneal injuries: a validation study.

    PubMed

    Frima, Herman; Eshuis, Rienk; Mulder, Paul; Leenen, Luke

    2012-06-01

    The integral classification of injuries (ICI), by Zwipp et al. has been developed as a classification system for injuries of the bones, joints, cartilage and ligaments of the foot. It follows the principles of the comprehensive classification of fractures by Müller et al. The ICI was developed for 'everyday use' and scientific purposes. Our aim was to perform a validation study for this classification system applied to the calcaneal injuries. A panel of five experienced trauma and orthopaedic surgeons evaluated the ICI score in 20 calcaneal injuries. After 2 months, a second classification was performed in a different order. Inter- and intra-observer variability were evaluated by kappa statistics. Panel members were not able to evaluate capsule and ligamental injuries based on X-ray and computed tomography (CT) films. Two injuries were excluded for logistical reasons. The inter-observer agreement based on 18 injuries of bone and joints was slight; kappa 0.14 (90% confidence interval (CI): 0.05-0.22). The intra-observer agreement was fair; kappa 0.31 (90% CI: 0.22-0.41). Overall, the panel rated the system as very complicated and not practical. The ICI is a complicated classification system with slight to fair inter- and intra-observer variabilities. It might not be a practical classification system for calcaneal injuries in 'everyday use' or scientific purposes. Copyright © 2011 Elsevier Ltd. All rights reserved.

  9. Patterns of Fracture and Tidal Stresses Due to Nonsynchronous Rotation: Implications for Fracturing on Europa

    NASA Technical Reports Server (NTRS)

    Parmentier, E. M.; Helfenstein, P.

    1985-01-01

    Global lineaments on Europa were interpreted as fractures in an icy crust. A variety of lineament types were identified, which appear to form a systematic pattern on the surface. For a synchronously rotating body, the patterns of fractures observed could be produced by a combination of stresses due to orbital recession, orbital eccentricity, and internal contraction. However, it was recently suggested that the forced eccentricity of Europa's orbit may result in nonsynchronous rotation. The hypothesis that fractures in a thin icy crust may have formed in response to stresses resulting from nonsynchronous rotation is studied.

  10. Magnetic resonance imaging in stress fractures and shin splints.

    PubMed

    Aoki, Yoshimitsu; Yasuda, Kazunori; Tohyama, Harukazu; Ito, Hirokazu; Minami, Akio

    2004-04-01

    The purpose of the current study was to determine whether stress fractures and shin splints could be discriminated with MRI in the early phase. Twenty-two athletes, who had pain in the middle or distal part of their leg during or after sports activity, were evaluated with radiographs and MRI scans. Stress fractures were diagnosed when consecutive radiographs showed local periosteal reaction or a fracture line, and shin splints were diagnosed in all the other cases. In all eight patients with stress fractures, an abnormally wide high signal in the localized bone marrow was the most detectable in the coronal fat-suppressed MRI scan. In 11 patients with shin splints, the coronal fat-suppressed MRI scans showed a linear abnormally high signal along the medial posterior surface of the tibia, and in seven patients with shin splints, the MRI scans showed a linear abnormally high signal along the medial bone marrow. No MRI scans of shin splints showed an abnormally wide high signal in the bone marrow as observed on MRI scans of stress fractures. This study showed that fat-suppressed MRI is useful for discrimination between stress fracture and shin splints before radiographs show a detectable periosteal reaction in the tibia.

  11. Vertical ground reaction forces in patients after calcaneal trauma surgery.

    PubMed

    van Hoeve, S; Verbruggen, J; Willems, P; Meijer, K; Poeze, M

    2017-10-01

    Vertical ground reaction forces (VGRFs) are altered in patients after foot trauma. It is not known if this correlates with ankle kinematics. The aim of this study was to analyze VGRFs in patients after calcaneal trauma and correlate them to patient-reported outcome measures (PROMs), radiographic findings and kinematic analysis, using a multi-segment foot model. In addition, we determined the predictive value of VGRFs to identify patients with altered foot kinematics. Thirteen patients (13 feet) with displaced intra-articular calcaneal fractures, were included an average of two years after trauma surgery. PROMs, radiographic findings on postoperative computed tomography scans, gait analysis using the Oxford foot model and VGRFs were analysed during gait. Results were compared with those of 11 healthy subjects (20 feet). Speed was equal in both groups, with healthy subjects walking at self-selected slow speed (0.94±0.18m/s) and patients after surgery walking at self-selected normal speed (0.94±0.29m/s). ROC curves were used to determine the predictive value. Patients after calcaneal surgery showed a lower minimum force during midstance (p=0.004) and a lower maximum force during toe-off (p=0.011). This parameter correlated significantly with the range of motion in the sagittal plane during the push-off phase (r 0.523, p=0.002), as well as with PROMs and with postoperative residual step-off (r 0.423, p=0.016). Combining these two parameters yielded a cut-off value of 193% (p<0.001), area under the curve 0.93 (95%confidence interval 0.84-1.00). Patients after calcaneal fracture showed lower minimum force during midstance and lower maximum force during toe-off compared to healthy subjects. This lower maximum force during push-off correlated significantly with PROMs, range of motion in the sagittal plane during push-off and radiographic postoperative residual step-off in the posterior facet of the calcaneal bone. VGRFs are a valuable screening tool for identifying

  12. Influence of fracture extension on in-situ stress in tight reservoir

    NASA Astrophysics Data System (ADS)

    Zhang, Yongping; Wei, Xu; Zhang, Ye; Xing, Libo; Xu, Jianjun

    2018-01-01

    Currently, hydraulic fracturing is an important way to develop low permeability reservoirs. The fractures produced during the fracturing process are the main influencing factors of changing in-situ stress. In this paper, the influence of fracture extension on in-situ stress is studied by establishing a mathematical model to describe the relationship between fracture length and in-situ stress. The results show that the growth rate gradually decreases after the fracture reaches a certain length with the increase of fracturing time; the continuous extension of the fracture is the main factor to change the in-situ stress. In order to reduce the impact on the subsequent fracture extension due to the changing of in-situ stress, controlling fracturing time and fracture length without affecting the stimulated reservoir effect is an important way. The results presented in this study can effectively reduce the impact of changing of in-situ stress on subsequent fracturing construction.

  13. Interpretation and classification of bone scintigraphic findings in stress fractures.

    PubMed

    Zwas, S T; Elkanovitch, R; Frank, G

    1987-04-01

    A new system for classification of stress fractures identified by bone scintigraphy was developed and divided into four grades according to lesion dimension, bone extension, and tracer accumulation. The scintigraphic findings were evaluated for severity of lesions by extent of the visualized bone response, ranging from ill-defined cortical lesions with slightly increased activity (I) to well-defined intramedullary transcortical lesions with intensely increased activity (IV). Bone scintigraphies using [99mTc]MDP were obtained in 310 military recruits suspected of having stress fractures. In 235 patients, 391 stress fractures were diagnosed. Forty percent of the lesions were asymptomatic. Most of the lesions were in the tibiae (72%), and 87% of the patients had one or two lesions, while 13% had three to five lesions. Eighty-five percent of the lesions were classified as mild and showed early and more complete resolution on follow-up studies after treatment as compared to the severe grades. Furthermore, specific scintigraphic patterns have been introduced for distinguishing inflammatory shin-splints from stress fractures, allowing for their appropriate early treatment. Thus, early recognition of mild stress fracture scintigraphic patterns representing the beginning of pathologic bone response to stress enabled a prompt and effective treatment to prevent progression of lesions, protracted disability, and complications.

  14. Probability of stress-corrosion fracture under random loading

    NASA Technical Reports Server (NTRS)

    Yang, J. N.

    1974-01-01

    Mathematical formulation is based on cumulative-damage hypothesis and experimentally-determined stress-corrosion characteristics. Under both stationary random loadings, mean value and variance of cumulative damage are obtained. Probability of stress-corrosion fracture is then evaluated, using principle of maximum entropy.

  15. Rehabilitation and return to running after lower limb stress fractures.

    PubMed

    Liem, Brian C; Truswell, Hallie J; Harrast, Mark A

    2013-01-01

    Lower limb stress fractures are common injuries in runners. In terms of treatment, much of the medical literature has focused primarily on rest and cessation of running, but little has been written about the rehabilitation and functional progression of runners following a lower limb stress fracture. This article reviews the scientific evidence behind common rehabilitation concepts used for runners recovering from these injuries and also discusses sport-specific training modalities such as deep water running and antigravity treadmill training. Overall this article is intended to be a practical resource for clinicians to guide runners in functional rehabilitation and return to running following lower limb stress injury.

  16. Taking a holistic approach to managing difficult stress fractures.

    PubMed

    Miller, Timothy L; Best, Thomas M

    2016-09-09

    Stress fractures and other bony stress injuries occur along a spectrum of severity which can impact treatment and prognosis. When treating these injuries, it should be borne in mind that no two stress fractures behave exactly alike. Given that they are not a consistent injury, standardized treatment protocols can be challenging to develop. Treatment should be individualized to the patient or athlete, the causative activity, the anatomical site, and the severity of the injury. A holistic approach to the treatment of the most difficult stress fractures should be taken by orthopedists and sports medicine specialists. This approach is necessary to obtain optimal outcomes, minimize loss of fitness and time away from sports participation, and decrease the risk of recurrence.

  17. Thermal stresses, differential subsidence, and flexure at oceanic fracture zones

    NASA Technical Reports Server (NTRS)

    Wessel, Pal; Haxby, William F.

    1990-01-01

    Geosat geoid undulations over four Pacific fracture zones have been analyzed. After correcting for the isostatic thermal edge effect, the amplitudes of the residuals are shown to be proportional to the age offset. The shape of the residuals seems to broaden with increasing age. Both geoid anomalies and available ship bathymetry data suggest that slip must sometimes occur on the main fracture zone or secondary faults. Existing models for flexure at fracture zones cannot explain the observed anomalies. A combination model accounting for slip and including flexure from thermal stresses and differential subsidence is presented. This model accounts for lateral variations in flexural rigidity from brittle and ductile yielding due to both thermal and flexural stresses and explains both the amplitudes and the shape of the anomalies along each fracture zone. The best fitting models have mechanical plate thicknesses that are described by the depth to the 600-700 C isotherms.

  18. Fracture toughness and the effects of stress state on fracture of nickel aluminides

    NASA Technical Reports Server (NTRS)

    Lewandowski, John J.; Michal, Gary M.; Locci, Ivan; Rigney, Joseph D.

    1991-01-01

    The effects of stress state on the fracture behavior of Ni3Al, Ni3Al + B, and NiAl were determined using either notched or fatigue-precracked bend bars tested to failure at room temperature, in addition to testing specimens in tension under superposed hydrostatic pressure. Although Ni3Al is observed to fail in a macroscopically brittle intergranular manner in tension tests conducted at room temperature, the fracture toughnesses presently obtained on Ni3Al exceeded 20 MPam, and R-curve behavior was exhibited. In situ monitoring of the fracture experiments was utilized to aid in interpreting the source(s) of the high toughness in Ni3Al, while SEM fractography was utilized to determine the operative fracture modes. The superposition by hydrostatic pressure during tensile testing of NiAl specimens was observed to produce increased ductility without changing the fracture mode.

  19. Stress fractures in athletes. How to spot this underdiagnosed injury.

    PubMed

    Sallis, R E; Jones, K

    1991-05-01

    Stress fractures are an increasingly common injury in competitive athletes, especially runners. Amenorrheic athletes are at particularly high risk. A radionuclide bone scan should be considered when the index of suspicion for stress fracture is high. Plain radiographs are of little use in establishing the diagnosis in the early stages of the injury. Early diagnosis and prompt institution of conservative therapy allow for a favorable outcome in most cases. Avoidance of or reduced participation in the inciting activity is important for pain control. Certain stress fractures, such as those involving the femoral neck, should be monitored closely and treated aggressively with internal fixation when conservative measures fail. Runners who have exercise-induced amenorrhea should be advised to decrease their training intensity to a level where menses resume. Cyclic therapy with conjugated estrogens and progesterone should also be considered, as should daily calcium supplementation.

  20. Tibial stress fracture after computer-navigated total knee arthroplasty.

    PubMed

    Massai, F; Conteduca, F; Vadalà, A; Iorio, R; Basiglini, L; Ferretti, A

    2010-06-01

    A correct alignment of the tibial and femoral component is one of the most important factors determining favourable long-term results of a total knee arthroplasty (TKA). The accuracy provided by the use of the computer navigation systems has been widely described in the literature so that their use has become increasingly popular in recent years; however, unpredictable complications, such as displaced or stress femoral or tibial fractures, have been reported to occur a few weeks after the operation. We present a case of a stress tibial fracture that occurred after a TKA performed with the use of a computer navigation system. The stress fracture, which eventually healed without further complications, occurred at one of the pinhole sites used for the placement of the tibial trackers.

  1. Correlation Between Fracture Network Properties and Stress Variability in Geological Media

    NASA Astrophysics Data System (ADS)

    Lei, Qinghua; Gao, Ke

    2018-05-01

    We quantitatively investigate the stress variability in fractured geological media under tectonic stresses. The fracture systems studied include synthetic fracture networks following power law length scaling and natural fracture patterns based on outcrop mapping. The stress field is derived from a finite-discrete element model, and its variability is analyzed using a set of mathematical formulations that honor the tensorial nature of stress data. We show that local stress perturbation, quantified by the Euclidean distance of a local stress tensor to the mean stress tensor, has a positive, linear correlation with local fracture intensity, defined as the total fracture length per unit area within a local sampling window. We also evaluate the stress dispersion of the entire stress field using the effective variance, that is, a scalar-valued measure of the overall stress variability. The results show that a well-connected fracture system under a critically stressed state exhibits strong local and global stress variabilities.

  2. Stress Fractures of Tibia Treated with Ilizarov External Fixator.

    PubMed

    Górski, Radosław; Żarek, Sławomir; Modzelewski, Piotr; Górski, Ryszard; Małdyk, Paweł

    2016-08-30

    Stress fractures are the result of cyclic loading of the bone, which gradually becomes damaged. Most often they are treated by rest or plaster cast and, in rare cases, by internal fixation. There is little published data on initial reposition followed by stabilization with the Ilizarov apparatus in such fractures. Six patients were treated with an external fixator according to the Ilizarov method for a stress fracture of the tibia between 2007 and 2015. Three patients were initially treated conservatively. Due to increasing tibial deformation, they were qualified for surgical treatment with external stabilization. In the other patients, surgery was the first-line treatment. All patients demonstrated risk factors for a stress fracture. After the surgery, they fully loaded the operated limb. No patient developed malunion, nonunion, infection or venous thrombosis. The average time from the first operation to the removal of the external fixator was 19 weeks. Radiographic and clinical outcomes were satisfactory in all patients. 1. The Ilizarov method allows for successful stabilization of stress fractures of the tibia. 2. It may be a good alternative to internal stabilization, especially in patients with multiple comorbidities which affect bone quality and may impair soft tissue healing.

  3. Stress Related Fracturing in Dimension Stone Quarries

    NASA Astrophysics Data System (ADS)

    Hamdi Deliormanli, Ahmet; Maerz, Norbert H.

    2016-10-01

    In Missouri, the horizontal stresses (pressures) in the near surface rock are uncommonly high. While the vertical stresses in rock are simply a function of the weight of the overlying rock, near surface stresses can be many times higher. The near surface horizontal stresses can be in excess of 5 times greater than the vertical stresses. In this research, Flatjack method was used to measure horizontal stress in Red Granite Quarry in Missouri. The flat jack method is an approved method of measuring ground stresses. A saw cut is used to “relax” the stress in the ground by allowing the rock to deform inwards the cut. A hydraulic flat jack is used to inflate the slot; to push the rock back to its stressed position, as measured by a strain gauge on either side of the slot. The pressure in the jack, when the rock is exactly back to its original position, is equal to the ground stress before the saw cut was made. According to the results, present production direction for each pit is not good because the maximum stress direction is perpendicular with production direction. This case causes unintentional breakage results in the loss rock. The results show that production direction should be changed.

  4. 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

  5. Hygrothermomechanical fracture stress criteria for fiber composites with sense-parity

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.; Ginty, C. A.

    1983-01-01

    Hygrothermomechanical fracture stress criteria are developed and evaluated for unidirectional composites (plies) with sense-parity. These criteria explicity quantify the individual contributions of applied, hygral and thermal stresses as well as couplings among these stresses. The criteria are for maximum stress, maximum strain, internal friction, work-to-fracture and combined-stress fracture. Predicted results obtained indicate that first ply failure will occur at stress levels lower than those predicted using criteria currently available in the literature. Also, the contribution of the various stress couplings (predictable only by fracture criteria with sense-parity) is significant to first ply failure and attendant fracture modes.

  6. Probability of stress-corrosion fracture under random loading.

    NASA Technical Reports Server (NTRS)

    Yang, J.-N.

    1972-01-01

    A method is developed for predicting the probability of stress-corrosion fracture of structures under random loadings. The formulation is based on the cumulative damage hypothesis and the experimentally determined stress-corrosion characteristics. Under both stationary and nonstationary random loadings, the mean value and the variance of the cumulative damage are obtained. The probability of stress-corrosion fracture is then evaluated using the principle of maximum entropy. It is shown that, under stationary random loadings, the standard deviation of the cumulative damage increases in proportion to the square root of time, while the coefficient of variation (dispersion) decreases in inversed proportion to the square root of time. Numerical examples are worked out to illustrate the general results.

  7. Surgical management of calcaneal unicameral bone cysts.

    PubMed

    Glaser, D L; Dormans, J P; Stanton, R P; Davidson, R S

    1999-03-01

    Unicameral bone cysts are not seen commonly in the calcaneus. Little is known about the etiology and natural history of these lesions. Calcaneal cysts often are symptomatic, although some of these lesions are detected as incidental findings. Treatment has been advocated based on the fear of pathologic fracture and collapse. Several published series have been divided in their favor for either open treatment or injection management. These series are small, and the optimal treatment is still in question. The current study compared the efficacy of methylprednisolone acetate injection treatment with curettage and bone grafting in the treatment of unicameral bone cysts of the calcaneus. All patients treated for unicameral bone cysts of the calcaneus during the past 7 years at two institutions were reviewed. Eleven patients met inclusion criteria. All diagnoses were confirmed radiographically or histologically. Demographic information, presenting complaints, diagnostic imaging, treatment modalities, and outcome were analyzed. Long term radiographic and subjective followup was obtained. Eighteen surgical procedures were performed on 11 patients with 12 cysts. Nine injections performed on six patients failed to show healing of the cyst. Nine cysts treated with curettage and bone grafting showed cyst healing. At mean followup of 28 months (range, 12-77 months), all 11 patients had no symptoms; there were no recurrences of the cyst in the nine patients who underwent bone grafting and persistence of the cyst in the two patients who underwent injection therapy. This review reports one of the largest series of cysts in this location. The results indicate that steroid injection treatment, although useful in other locations, may not be the best option for the management of unicameral bone cysts in the calcaneus. Curettage and bone grafting yielded uniformly good results.

  8. Dietary intake and stress fractures among elite male combat recruits.

    PubMed

    Moran, Daniel S; Heled, Yuval; Arbel, Yael; Israeli, Eran; Finestone, Aharon S; Evans, Rachel K; Yanovich, Ran

    2012-03-13

    Appropriate and sufficient dietary intake is one of the main requirements for maintaining fitness and health. Inadequate energy intake may have a negative impact on physical performance which may result in injuries among physically active populations. The purpose of this research was to evaluate a possible relationship between dietary intake and stress fracture occurrence among combat recruits during basic training (BT). Data was collected from 74 combat recruits (18.2 ± 0.6 yrs) in the Israeli Defense Forces. Data analyses included changes in anthropometric measures, dietary intake, blood iron and calcium levels. Measurements were taken on entry to 4-month BT and at the end of BT. The occurrence of stress reaction injury was followed prospectively during the entire 6-month training period. Twelve recruits were diagnosed with stress fracture in the tibia or femur (SF group). Sixty two recruits completed BT without stress fractures (NSF). Calcium and vitamin D intakes reported on induction day were lower in the SF group compared to the NSF group-38.9% for calcium (589 ± 92 and 964 ± 373 mg·d-1, respectively, p < 0.001), and-25.1% for vitamin D (117.9 ± 34.3 and 157.4 ± 93.3 IU·d-1, respectively, p < 0.001). During BT calcium and vitamin D intake continued to be at the same low values for the SF group but decreased for the NSF group and no significant differences were found between these two groups. The development of stress fractures in young recruits during combat BT was associated with dietary deficiency before induction and during BT of mainly vitamin D and calcium. For the purpose of intervention, the fact that the main deficiency is before induction will need special consideration.

  9. [Tibio-talo-calcaneal arthrodesis with the retrograde intramedullary nail MEDIN].

    PubMed

    Popelka, S; Vavřík, P; Landor, I; Bek, J; Popelka ml, S; Hromádka, R

    2013-01-01

    When the talus and the talocalcaneal joint are both affected, their fusion is the method of treatment. Ankle arthrodesis is carried out using various osteosynthetic materials such as external fixators, screws and plates. One of the options is retrograde nailing. Tibio-talo-calcaneal arthrodesis is frequently indicated in patients with rheumatoid arthritis (RA) in whom both the talus and the subtalar joint are often affected. A retrograde nail for tibio-talo-calcaneal arthrodesis was developed at our department in cooperation with MEDIN Company. This is a titanium double-curved nail, with the distal part bent at 8 degrees ventrally and 10 degrees laterally. It is inserted from the transfibular approach. Sixty-two patients, 35 women and 27 men, were treated at our department from 2005. Since one patient had bilateral surgery, 63 ankles were included. The indications for arthrodesis involved rheumatoid arthritis in 42, post-traumatic arthritis in 10, failed ankle arthrodesis in two and failed total ankle arthroplasty in five ankles; tibial stress fractures close above the ankle in two RA patients, one patient with dermatomyositis and one with lupus erythematodes. The average age at the time of surgery was 64.2 years (range, 30 to 80). The average follow-up was 4.5 years (range, 1 to 9 years), Satisfaction with the treatment outcome and willingness to undergo surgery on the other side were reported by 82% of the patients. The AOFAS score improved from 35 to 74 points. Three (4.8%) patients complained of painful feet due to the fact that exact correction of the calcaneus was not achieved and the heel after arthrodesis remained in a slightly varus position. Of them, two had a failed total ankle arthroplasty. Post-operative complications included early infection managed by antibiotic treatment and early surgical revision with irrigation.in two (3.2%) RA patients, who were undergoing biological therapy. Late infection developed at 2 to 3 years after surgery in three (4

  10. Penile fracture seems more likely during sex under stressful situations.

    PubMed

    Kramer, Andrew C

    2011-12-01

    The unusual event of penile fracture occurs when there is a disruption of the tunica albuginea surrounding engorged erectile tissue during aggressive sexual behavior. There is often an audible crack and rapid detumescence with subcutaneous hemorrhage that follows. Medical literature has described the etiology and treatment of penile fracture. We report the remarkably unusual social situations of a series of patients who sustained this unique injury. We conducted a retrospective chart review of 16 patients whose injury was severe enough to require surgical repair at the University of Maryland between 2007 and 2011. Particular attention was paid to the intake interview in the emergency department and the postoperative chart notes by the attending urologist to ascertain out-of-the-ordinary social situations in which the injury was sustained. The occurrence of penile fracture is sufficiently rare that the author was able to interact personally with most of the patients. The patients were remarkably forthcoming with the personal social dynamics of the sexual encounter. Half of these penile fracture patients sustained the injury during an extramarital affair. Only three patients sustained the injury in a bedroom; the remainder was in out-of-the-ordinary locations for sexual intercourse, e.g., cars, elevator, the workplace, and public restrooms. Penile fracture patients appear to be a unique population of men who are having sexual intercourse under stressful situations. Extramarital affairs and out-of-the-ordinary locations appear common in patients sustaining this relatively rare injury. © 2011 International Society for Sexual Medicine.

  11. Fracture and Stress Evolution on Europa: New Insights Into Fracture Interpretation and Ice Thickness Estimates Using Fracture Mechanics Analyses

    NASA Technical Reports Server (NTRS)

    Kattenhorn, Simon

    2004-01-01

    The work completed during the funding period has provided many important insights into fracturing behavior in Europa's ice shell. It has been determined that fracturing through time is likely to have been controlled by the effects of nonsynchronous rotation stresses and that as much as 720 deg of said rotation may have occurred during the visible geologic history. It has been determined that there are at least two distinct styles of strike-slip faulting and that their mutual evolutionary styles are likely to have been different, with one involving a significant dilational component during shear motion. It has been determined that secondary fracturing in perturbed stress fields adjacent to older structures such as faults is a prevalent process on Europa. It has been determined that cycloidal ridges are likely to experience shear stresses along the existing segment portions as they propagate, which affects propagation direction and ultimately induces tailcracking at the segment tip than then initiates a new cycle of cycloid segment growth. Finally, it has been established that mechanical methods (e.g., flexure analysis) can be used to determine the elastic thickness of the ice shell, which, although probably only several km thick, is likely to be spatially variable, being thinner under bands but thicker under ridged plains terrain.

  12. The running athlete: stress fractures, osteitis pubis, and snapping hips.

    PubMed

    Henning, P Troy

    2014-03-01

    Pelvic stress fractures, osteitis pubis, and snapping hip syndrome account for a portion of the overuse injuries that can occur in the running athlete. PUBMED SEARCHES WERE PERFORMED FOR EACH ENTITY USING THE FOLLOWING KEYWORDS: snapping hip syndrome, coxa sultans, pelvic stress fracture, and osteitis pubis from 2008 to 2013. Topic reviews, case reports, case series, and randomized trials were included for review. Clinical review. Level 4. Collectively, 188 articles were identified. Of these, 58 were included in this review. Based on the available evidence, the majority of these overuse injuries can be managed non-operatively. Primary treatment should include removal from offending activity, normalizing regional muscle strength/length imbalances and nutritional deficiencies, and mitigating training errors through proper education of the athlete and training staff. C.

  13. Biomechanical Factors in the Etiology of Tibial Stress Fractures

    DTIC Science & Technology

    2006-08-01

    stiffness in these runners. A “stiff” runner will spend less time in contact with the ground (Farley and Gonzalez, 1996 ) and will attenuate less shock...between the leg and the head (McMahon et al., 1987). This is in agreement with the findings of Farley and Gonzalez ( 1996 ) who suggested lower...Army Natick Research and Development Laboratories. Brukner, P., Bradshaw, C., Khan, K., White, S. and Crossley, K. ( 1996 ) Stress fractures: a

  14. RANK/RANKL/OPG pathway: genetic associations with stress fracture period prevalence in elite athletes.

    PubMed

    Varley, Ian; Hughes, David C; Greeves, Julie P; Stellingwerff, Trent; Ranson, Craig; Fraser, William D; Sale, Craig

    2015-02-01

    The RANK/RANKL/OPG signalling pathway is important in the regulation of bone turnover, with single nucleotide polymorphisms (SNPs) in genes within this pathway associated with bone phenotypic adaptations. To determine whether four SNPs associated with genes in the RANK/RANKL/OPG signalling pathway were associated with stress fracture injury in elite athletes. Radiologically confirmed stress fracture history was reported in 518 elite athletes, forming the Stress Fracture Elite Athlete (SFEA) cohort. Data were analysed for the whole group and were sub-stratified into male and cases of multiple stress fracture groups. Genotypes were determined using proprietary fluorescence-based competitive allele-specific PCR assays. SNPs rs3018362 (RANK) and rs1021188 (RANKL) were associated with stress fracture injury (P<0.05). 8.1% of the stress fracture group and 2.8% of the non-stress fracture group were homozygote for the rare allele of rs1021188. Allele frequency, heterozygotes and homozygotes for the rare allele of rs3018362 were associated with stress fracture period prevalence (P<0.05). Analysis of the male only group showed 8.2% of rs1021188 rare allele homozygotes had suffered a stress fracture whilst 2.5% of the non-stress fracture group were homozygous. In cases of multiple stress fractures, homozygotes for the rare allele of rs1021188 and individuals possessing at least one copy of the rare allele of rs4355801 (OPG) were shown to be associated with stress fracture injury (P<0.05). The data support an association between SNPs in the RANK/RANKL/OPG signalling pathway and the development of stress fracture injury. The association of rs3018362 (RANK) and rs1021188 (RANKL) with stress fracture injury susceptibility supports their role in the maintenance of bone health and offers potential targets for therapeutic interventions. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Expected Time to Return to Athletic Participation After Stress Fracture in Division I Collegiate Athletes.

    PubMed

    Miller, Timothy L; Jamieson, Marissa; Everson, Sonsecharae; Siegel, Courtney

    2017-12-01

    Few studies have documented expected time to return to athletic participation after stress fractures in elite athletes. Time to return to athletic participation after stress fractures would vary by site and severity of stress fracture. Retrospective cohort study. Level 3. All stress fractures diagnosed in a single Division I collegiate men's and women's track and field/cross-country team were recorded over a 3-year period. Site and severity of injury were graded based on Kaeding-Miller classification system for stress fractures. Time to return to full unrestricted athletic participation was recorded for each athlete and correlated with patient sex and site and severity grade of injury. Fifty-seven stress fractures were diagnosed in 38 athletes (mean age, 20.48 years; range, 18-23 years). Ten athletes sustained recurrent or multiple stress fractures. Thirty-seven injuries occurred in women and 20 in men. Thirty-three stress fractures occurred in the tibia, 10 occurred in the second through fourth metatarsals, 3 occurred in the fifth metatarsal, 6 in the tarsal bones (2 navicular), 2 in the femur, and 5 in the pelvis. There were 31 grade II stress fractures, 11 grade III stress fractures, and 2 grade V stress fractures (in the same patient). Mean time to return to unrestricted sport participation was 12.9 ± 5.2 weeks (range, 6-27 weeks). No significant differences in time to return were noted based on injury location or whether stress fracture was grade II or III. The expected time to return to full unrestricted athletic participation after diagnosis of a stress fracture is 12 to 13 weeks for all injury sites. Athletes with grade V (nonunion) stress fractures may require more time to return to sport.

  16. Understanding the etiology of the posteromedial tibial stress fracture.

    PubMed

    Milgrom, Charles; Burr, David B; Finestone, Aharon S; Voloshin, Arkady

    2015-09-01

    Previous human in vivo tibial strain measurements from surface strain gauges during vigorous activities were found to be below the threshold value of repetitive cyclical loading at 2500 microstrain in tension necessary to reduce the fatigue life of bone, based on ex vivo studies. Therefore it has been hypothesized that an intermediate bone remodeling response might play a role in the development of tibial stress fractures. In young adults tibial stress fractures are usually oblique, suggesting that they are the result of failure under shear strain. Strains were measured using surface mounted unstacked 45° rosette strain gauges on the posterior aspect of the flat medial cortex just below the tibial midshaft, in a 48year old male subject while performing vertical jumps, staircase jumps and running up and down stadium stairs. Shear strains approaching 5000 microstrain were recorded during stair jumping and vertical standing jumps. Shear strains above 1250 microstrain were recorded during runs up and down stadium steps. Based on predictions from ex vivo studies, stair and vertical jumping tibial shear strain in the test subject was high enough to potentially produce tibial stress fracture subsequent to repetitive cyclic loading without necessarily requiring an intermediate remodeling response to microdamage. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Direct Imaging of Natural Fractures and Stress Compartments Stimulated by Hydraulic Fracturing

    NASA Astrophysics Data System (ADS)

    Lacazette, A.; Vermilye, J. M.

    2014-12-01

    This contribution will present results from passive seismic studies of hydraulic fracture treatments in North American and Asian basins. One of the key data types is a comparatively new surface-based seismic imaging product - "Tomographic Fracture Images®" (TFI®). The procedure is an extension of Seismic Emission Tomography (SET), which is well-established and widely used. Conventional microseismic results - microearthquake hypocenter locations, magnitudes, and focal mechanism solutions - are also obtained from the data via a branch of the processing workflow. TFI is accomplished by summing the individual time steps in a multidimensional SET hypervolume over extended periods of time, such as an entire frac stage. The dimensions of a SET hypervolume are the X, Y, and Z coordinates of the voxels, the time step (typically on the order of 100 milliseconds), and the seismic activity value. The resulting summed volume is skeletonized to produce images of the main fracture surfaces, which are known to occupy the maximum activity surfaces of the high activity clouds from theory, field studies, and experiments. The orientation vs. area of the resulting TFIs can be analyzed in detail and compared with independent data sets such as volumetric structural attributes from reflection seismic data and borehole fracture data. We find that the primary effect of hydraulic fracturing is to stimulate preexisting natural fracture networks and faults. The combination of TFIs with hypocenter distributions and microearthquake focal mechanisms provides detailed information on subsurface stress compartmentalization. Faults are directly imaged which allows discrimination of fault planes from auxiliary planes of focal mechanism solutions. Examples that will be shown include simultaneous movement on a thrust fault and tear fault and examples of radically different stress compartments (e.g. extensional vs. wrench faulting) stimulated during a single hydraulic fracture treatment. The figure

  18. The effect of stress fracture interventions in a single elite infantry training unit (1983-2015).

    PubMed

    Milgrom, Charles; Finestone, Aharon S

    2017-10-01

    Stress fractures can be seen as an undesired byproduct of demanding physical training. The threshold value of stress that places an individual bone at high risk for stress fracture has not been identified. In a prospective study of stress fractures in 1983, a 31% incidence was found during demanding Israeli infantry basic training by bone scan criteria. Within a subgroup of these recruits, an elite infantry unit was found to have a 40% incidence. Since then and until 2015, eight additional induction companies of the same elite infantry unit were prospectively monitored for stress fractures during their basic training. In all of the studies, stress fracture surveillance and the examining orthopedist were the same. A retrospective review of all nine studies and of eight training changes was performed to look for a temporal trend in stress fracture incidence and to see if these might be related to training changes. There was a statistically significant trend for lower radiological proven stress fractures (p=0.0001) and radiological proven stress fractures plus clinical stress fractures (p=0.0013), as well as lower stress fracture severity by radiological criteria (p=0.0001) between 1983 and 2015. The only training change that was associated, by multivariate logistic regression, with a decreased incidence of stress fracture was restricting training to the authorized training protocol (odds ratio, 3874; 95% CI, 1.526 to 9.931; p=0.004). Increased recruit weight was found by multivariate analysis to be associated with lower stress fracture incidence (odds ratio 1.034; 95% CI, 1.00 to 1.070; p=0.051). Moving the training to a base with flatter terrain and reducing the formal marching distance by 1/3 was associated with a decrease in high grade stress fractures (odds ratio, 10.03; 95% CI, 3.5 to 28.4; p=0.0001). Neither the combined changes of enforcing a seven hour a night sleep regimen, training in more comfortable boots and adding a physical therapist to the unit nor

  19. A mechanical model of metatarsal stress fracture during distance running.

    PubMed

    Gross, T S; Bunch, R P

    1989-01-01

    A model of metatarsal mechanics has been proposed as a link between the high incidence of second and third metatarsal stress fractures and the large stresses measured beneath the second and third metatarsal heads during distance running. Eight discrete piezoelectric vertical stress transducers were used to record the forefoot stresses of 21 male distance runners. Based upon load bearing area estimates derived from footprints, plantar forces were estimated. Highest force was estimated beneath the second and first metatarsal head (341.1 N and 279.1 N, respectively). Considering the toe as a hinged cantilever and the metatarsal as a proximally attached rigid cantilever allowed estimation of metatarsal midshaft bending strain, shear, and axial forces. Bending strain was estimated to be greatest in the second metatarsal (6662 mu epsilon), a value 6.9 times greater than estimated first metatarsal strain. Predicted third, fourth, and fifth metatarsal strains ranged between 4832 and 5241 mu epsilon. Shear force estimates were also greatest in the second metatarsal (203.0 N). Axial forces were highest in the first metatarsal (593.2 N) due to large hallux forces in relationship to the remaining toes. Although a first order model, these data highlight the structural demands placed upon the second metatarsal, a location of high metatarsal stress fracture incidence during distance running.

  20. 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.

  1. Treatment of subtalar calcanean fractures using trans-osseous limited lateral approach.

    PubMed

    Ragab, Abdelaleem H; Mubark, Islam M; Nagi, Ahmed M; Abdelnaby, Mohamed Aly

    2014-01-01

    Calcaneal fractures are the most common fractures of the tarsal bones. The majority of these fractures are produced by axial force like a fall from a height. Controversy still exists on the best line of treatment. This study is to evaluate the results of trans-osseous limited lateral approach as a minimally invasive surgical treatment of the displaced intra-articular calcaneal fractures. The study included forty two patients (46 feet) with displaced intra-articular calcaneal fractures admitted to El-Hadra University Hospital. They were treated by trans-osseous open reduction of subtalar joint and internal fixation by k-wires consuming the trans-osseous limited lateral approach. Out of 42 patients, 36 pateints (85.7%) were males. Using calcaneal fracture scoring system, the mean score was 67.55+17.35. Satisfactory results were found in 26 patients (61.9%), while 16 patients (38.1%) had unsatisfactory results. There was significant relationship between classification of the fracture and the final results (the more the grade of the fracture, the worse the final score) (x 2 =5.914, p=0.05). The value of calcaneal angles were significantly improved after surgery including bohler angle (p=0.0001), gissane angle (p=0.0001), calcaneal pitch angle (p=0.001) and calcaneofibular space (p=0.0021). 1. Trans-osseous limited lateral approach is an effective method for management of intra articular calcaneal fractures. 2. Anatomical reduction for intra articular calcaneal fractures is essential. 3. Functional outcome of intra articular calcaneal fractures depends upon the initial damage of the articular cartilage. 4. There is a need for multi-center prospective randomized study for accurate assessment of the results of operative management of intra articular calcaneal fractures involving pre and post-operative CT for assessment of reduction and using a rational scoring system and a long period of follow up.

  2. Classification of Calcaneal Spurs and Their Relationship With Plantar Fasciitis.

    PubMed

    Zhou, Binghua; Zhou, You; Tao, Xu; Yuan, Chengsong; Tang, Kanglai

    2015-01-01

    Calcaneal spurs, as a cause of plantar fasciitis, are currently debatable. A prospective study was performed to classify calcaneal spurs according to the findings from an investigation of the relationship between calcaneal spurs and plantar fasciitis. Thirty patients with calcaneal spurs and plantar heel pain underwent calcaneal spur removal and endoscopic plantar fasciotomy. The relationship between the classification of calcaneal spurs and plantar fasciitis was evaluated by endoscopic findings, clinical symptoms, radiographic images, and biopsy findings. The visual analog scale for pain and the American Orthopedic Foot and Ankle Society ankle-hindfoot scores for functional evaluation were used preoperatively and postoperatively, respectively. The mean follow-up period was 24 months. Two separate types of calcaneal spurs were recognized. Type A calcaneal spurs were located superior to the plantar fascia insertion, and type B calcaneal spurs were located within the plantar fascia. Magnetic resonance imaging results showed a more severe plantar fasciitis grade in type B calcaneal spurs preoperatively. Histologic examination showed that the numbers of granulocytes per image in type B spurs were significantly increased compared with those in type A spurs. Statistically significant improvements were found in the mean visual analog scale and American Orthopedic Foot and Ankle Society scores and magnetic resonance imaging results in both groups. The amount of change in the visual analog scale score and American Orthopedic Foot and Ankle Society score, the number of granulocytes per image, and calcaneal spur length showed a high association with the classification of the calcaneal spurs. Calcaneal spurs were completely removed and did not recur in any of the patients on radiographic assessment during the follow-up period. Calcaneal spurs can be classified into 2 distinct types that are indicative of the severity of plantar fasciitis. Copyright © 2015 American College of

  3. 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

  4. Diagnosis, treatment, and rehabilitation of stress fractures in the lower extremity in runners

    PubMed Central

    Kahanov, Leamor; Eberman, Lindsey E; Games, Kenneth E; Wasik, Mitch

    2015-01-01

    Stress fractures account for between 1% and 20% of athletic injuries, with 80% of stress fractures in the lower extremity. Stress fractures of the lower extremity are common injuries among individuals who participate in endurance, high load-bearing activities such as running, military and aerobic exercise and therefore require practitioner expertise in diagnosis and management. Accurate diagnosis for stress fractures is dependent on the anatomical area. Anatomical regions such as the pelvis, sacrum, and metatarsals offer challenges due to difficulty differentiating pathologies with common symptoms. Special tests and treatment regimes, however, are similar among most stress fractures with resolution between 4 weeks to a year. The most difficult aspect of stress fracture treatment entails mitigating internal and external risk factors. Practitioners should address ongoing risk factors to minimize recurrence. PMID:25848327

  5. The role of local stress perturbation on the simultaneous opening of orthogonal fractures

    NASA Astrophysics Data System (ADS)

    Boersma, Quinten; Hardebol, Nico; Barnhoorn, Auke; Bertotti, Giovanni; Drury, Martyn

    2016-04-01

    Orthogonal fracture networks (ladder-like networks) are arrangements that are commonly observed in outcrop studies. They form a particularly dense and well connected network which can play an important role in the effective permeability of tight hydrocarbon or geothermal reservoirs. One issue is the extent to which both the long systematic and smaller cross fractures can be simultaneously critically stressed under a given stress condition. Fractures in an orthogonal network form by opening mode-I displacements in which the main component is separation of the two fracture walls. This opening is driven by effective tensile stresses as the smallest principle stress acting perpendicular to the fracture wall, which accords with linear elastic fracture mechanics. What has been well recognized in previous field and modelling studies is how both the systematic fractures and perpendicular cross fractures require the minimum principle stress to act perpendicular to the fracture wall. Thus, these networks either require a rotation of the regional stress field or local perturbations in stress field. Using a mechanical finite element modelling software, a geological case of layer perpendicular systematic mode I opening fractures is generated. New in our study is that we not only address tensile stresses at the boundary, but also address models using pore fluid pressure. The local stress in between systematic fractures is then assessed in order to derive the probability and orientation of micro crack propagation using the theory of sub critical crack growth and Griffith's theory. Under effective tensile conditions, the results indicate that in between critically spaced systematic fractures, local effective tensile stresses flip. Therefore the orientation of the least principle stress will rotate 90°, hence an orthogonal fracture is more likely to form. Our new findings for models with pore fluid pressures instead of boundary tension show that the magnitude of effective tension

  6. Determination of In-Situ Stresses Around Underground Excavations by Means of Hydraulic Fracturing

    DTIC Science & Technology

    inhomogeneous, precracked variable rock is suitable for hydraulic fracturing as a method of in-situ stress measurement. It was found that basically the Coeur...d’Alene quartzite is amenable to hydraulic fracturing testing. The rock has no consistent anisotropy, but is inhomogeneous with physical property...horizontal stress notwithstanding rock condition. Field stress measurements in the Coeur d’Alene mines using the hydraulic fracturing technique are recommended.

  7. Mechanisms Underlying Stress Fracture and the Influence of Sex and Race/Ethnicity

    DTIC Science & Technology

    2017-10-01

    penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN...history of one stress fracture (n=25), or no stress fracture history (n=25). The discrepancies in these parameters between groups will help to...women (n=40 for each group ; n=240 total). This will serve to identify factors that contribute to the differences in stress fracture incidence due to race

  8. Analysis of stress fractures in athletes based on our clinical experience

    PubMed Central

    Iwamoto, Jun; Sato, Yoshihiro; Takeda, Tsuyoshi; Matsumoto, Hideo

    2011-01-01

    AIM: To analyze stress fractures in athletes based on experience from our sports medicine clinic. METHODS: We investigated the association between stress fractures and age, sex, sports level, sports activity, and skeletal site in athletes seen at our sports medicine clinic between September 1991 and April 2009. Stress fractures of the pars interarticularis were excluded from this analysis. RESULTS: During this period (18 years and 8 mo), 14276 patients (9215 males and 5061 females) consulted our clinic because of sports-related injuries, and 263 patients (1.8%) [171 males (1.9%) and 92 females (1.8%)] sustained stress fractures. The average age of the patients with stress fractures was 20.2 years (range 10-46 years); 112 patients (42.6%) were 15-19 years of age and 90 (34.2%) were 20-24 years of age. Altogether, 90 patients (34.2%) were active at a high recreational level and 173 (65.8%) at a competitive level. The highest proportion of stress fractures was seen in basketball athletes (21.3%), followed by baseball (13.7%), track and field (11.4%), rowing (9.5%), soccer (8.4%), aerobics (5.3%), and classical ballet (4.9%). The most common sites of stress fractures in these patients were the tibia (44.1%), followed by the rib (14.1%), metatarsal bone (12.9%), ulnar olecranon (8.7%) and pelvis (8.4%). The sites of the stress fractures varied from sport to sport. The ulnar olecranon was the most common stress fracture site in baseball players, and the rib was the most common in rowers. Basketball and classical ballet athletes predominantly sustained stress fractures of the tibia and metatarsal bone. Track and field and soccer athletes predominantly sustained stress fractures of the tibia and pubic bone. Aerobics athletes predominantly sustained stress fractures of the tibia. Middle and long distance female runners who sustained multiple stress fractures had the female athlete triad. CONCLUSION: The results of this analysis showed that stress fractures were seen in high

  9. The Contribution of SPECT/CT in the Diagnosis of Stress Fracture of the Proximal Tibia.

    PubMed

    Okudan, Berna; Coşkun, Nazım; Arıcan, Pelin

    2018-02-01

    Stress fractures are injuries most commonly seen in the lower limbs and are usually caused by repetitive stress. While the distal and middle third of the tibia is the most frequent site for stress fractures (almost 50%), stress fractures of the proximal tibia is relatively rare and could be confused with other types of tibial fractures, thus altering management plans for the clinician. Early diagnosis of stress fractures is also important to avoid complications. Imaging plays an important role in the diagnosis of stress fractures, especially bone scan. Combined with single-photon emission computed tomography/computed tomography (SPECT/CT) it is an important imaging technique for stress fractures in both upper and lower extremities, and is widely preferred over other imaging techniques. In this case, we present the case of a 39-year-old male patient diagnosed with stress fracture of the proximal tibia and demonstrate the contribution of CT scan fused with SPECT imaging in the early diagnosis of stress fracture prior to other imaging modalities.

  10. Chondromalacia of trochlear notch after healing of olecranon stress fracture: a case report.

    PubMed

    Lu, Cheng-Chang; Chen, Shen-Kai; Wang, Chih-Wei; Chou, Pei-Hsi

    2006-05-01

    Chondromalacia of the trochlear notch and stress fracture of olecranon are uncommon injuries in the throwing athletes. We report an 18-year-old high school pitcher who had persistent postero-lateral elbow pain after a healed olecranon stress fracture of the right elbow. Diagnostic arthroscopy revealed chondromalacia of the trochlear notch. After treatment with arthroscopic drilling and abrasion chondroplasty, he returned to competitive pitching 1 year later postsurgery. This rare association between chondromalacia and stress fracture of the olecranon has not been reported previously in the literatures. Chondromalacia of the trochlear notch should be included as a differential diagnosis in evaluating athletes with persistent elbow pain after healed olecranon stress fractures.

  11. Dynamic fracture of tantalum under extreme tensile stress

    DOE PAGES

    Albertazzi, Bruno; Ozaki, Norimasa; Zhakhovsky, Vasily; ...

    2017-06-02

    The understanding of fracture phenomena of a material at extremely high strain rates is a key issue for a wide variety of scientific research ranging from applied science and technological developments to fundamental science such as laser-matter interaction and geology. Despite its interest, its study relies on a fine multiscale description, in between the atomic scale and macroscopic processes, so far only achievable by large-scale atomic simulations. Direct ultrafast real-time monitoring of dynamic fracture (spallation) at the atomic lattice scale with picosecond time resolution was beyond the reach of experimental techniques. We show that the coupling between a high-power opticalmore » laser pump pulse and a femtosecond x-ray probe pulse generated by an x-ray free electron laser allows detection of the lattice dynamics in a tantalum foil at an ultrahigh strain rate of Embedded Image ~2 × 10 8 to 3.5 × 10 8 s -1. A maximal density drop of 8 to 10%, associated with the onset of spallation at a spall strength of ~17 GPa, was directly measured using x-ray diffraction. The experimental results of density evolution agree well with large-scale atomistic simulations of shock wave propagation and fracture of the sample. Our experimental technique opens a new pathway to the investigation of ultrahigh strain-rate phenomena in materials at the atomic scale, including high-speed crack dynamics and stress-induced solid-solid phase transitions.« less

  12. Dynamic fracture of tantalum under extreme tensile stress.

    PubMed

    Albertazzi, Bruno; Ozaki, Norimasa; Zhakhovsky, Vasily; Faenov, Anatoly; Habara, Hideaki; Harmand, Marion; Hartley, Nicholas; Ilnitsky, Denis; Inogamov, Nail; Inubushi, Yuichi; Ishikawa, Tetsuya; Katayama, Tetsuo; Koyama, Takahisa; Koenig, Michel; Krygier, Andrew; Matsuoka, Takeshi; Matsuyama, Satoshi; McBride, Emma; Migdal, Kirill Petrovich; Morard, Guillaume; Ohashi, Haruhiko; Okuchi, Takuo; Pikuz, Tatiana; Purevjav, Narangoo; Sakata, Osami; Sano, Yasuhisa; Sato, Tomoko; Sekine, Toshimori; Seto, Yusuke; Takahashi, Kenjiro; Tanaka, Kazuo; Tange, Yoshinori; Togashi, Tadashi; Tono, Kensuke; Umeda, Yuhei; Vinci, Tommaso; Yabashi, Makina; Yabuuchi, Toshinori; Yamauchi, Kazuto; Yumoto, Hirokatsu; Kodama, Ryosuke

    2017-06-01

    The understanding of fracture phenomena of a material at extremely high strain rates is a key issue for a wide variety of scientific research ranging from applied science and technological developments to fundamental science such as laser-matter interaction and geology. Despite its interest, its study relies on a fine multiscale description, in between the atomic scale and macroscopic processes, so far only achievable by large-scale atomic simulations. Direct ultrafast real-time monitoring of dynamic fracture (spallation) at the atomic lattice scale with picosecond time resolution was beyond the reach of experimental techniques. We show that the coupling between a high-power optical laser pump pulse and a femtosecond x-ray probe pulse generated by an x-ray free electron laser allows detection of the lattice dynamics in a tantalum foil at an ultrahigh strain rate of [Formula: see text] ~2 × 10 8 to 3.5 × 10 8 s -1 . A maximal density drop of 8 to 10%, associated with the onset of spallation at a spall strength of ~17 GPa, was directly measured using x-ray diffraction. The experimental results of density evolution agree well with large-scale atomistic simulations of shock wave propagation and fracture of the sample. Our experimental technique opens a new pathway to the investigation of ultrahigh strain-rate phenomena in materials at the atomic scale, including high-speed crack dynamics and stress-induced solid-solid phase transitions.

  13. Dynamic fracture of tantalum under extreme tensile stress

    PubMed Central

    Albertazzi, Bruno; Ozaki, Norimasa; Zhakhovsky, Vasily; Faenov, Anatoly; Habara, Hideaki; Harmand, Marion; Hartley, Nicholas; Ilnitsky, Denis; Inogamov, Nail; Inubushi, Yuichi; Ishikawa, Tetsuya; Katayama, Tetsuo; Koyama, Takahisa; Koenig, Michel; Krygier, Andrew; Matsuoka, Takeshi; Matsuyama, Satoshi; McBride, Emma; Migdal, Kirill Petrovich; Morard, Guillaume; Ohashi, Haruhiko; Okuchi, Takuo; Pikuz, Tatiana; Purevjav, Narangoo; Sakata, Osami; Sano, Yasuhisa; Sato, Tomoko; Sekine, Toshimori; Seto, Yusuke; Takahashi, Kenjiro; Tanaka, Kazuo; Tange, Yoshinori; Togashi, Tadashi; Tono, Kensuke; Umeda, Yuhei; Vinci, Tommaso; Yabashi, Makina; Yabuuchi, Toshinori; Yamauchi, Kazuto; Yumoto, Hirokatsu; Kodama, Ryosuke

    2017-01-01

    The understanding of fracture phenomena of a material at extremely high strain rates is a key issue for a wide variety of scientific research ranging from applied science and technological developments to fundamental science such as laser-matter interaction and geology. Despite its interest, its study relies on a fine multiscale description, in between the atomic scale and macroscopic processes, so far only achievable by large-scale atomic simulations. Direct ultrafast real-time monitoring of dynamic fracture (spallation) at the atomic lattice scale with picosecond time resolution was beyond the reach of experimental techniques. We show that the coupling between a high-power optical laser pump pulse and a femtosecond x-ray probe pulse generated by an x-ray free electron laser allows detection of the lattice dynamics in a tantalum foil at an ultrahigh strain rate of ε. ~2 × 108 to 3.5 × 108 s−1. A maximal density drop of 8 to 10%, associated with the onset of spallation at a spall strength of ~17 GPa, was directly measured using x-ray diffraction. The experimental results of density evolution agree well with large-scale atomistic simulations of shock wave propagation and fracture of the sample. Our experimental technique opens a new pathway to the investigation of ultrahigh strain-rate phenomena in materials at the atomic scale, including high-speed crack dynamics and stress-induced solid-solid phase transitions. PMID:28630909

  14. Imaging of upper extremity stress fractures in the athlete.

    PubMed

    Anderson, Mark W

    2006-07-01

    Although it is much less common than injuries in the lower extremities, an upper extremity stress injury can have a significant impact on an athlete. If an accurate and timely diagnosis is to be made, the clinician must have a high index of suspicion of a stress fracture in any athlete who is involved in a throwing, weightlifting, or upper extremity weight-bearing sport and presents with chronic pain in the upper extremity. Imaging should play an integral role in the work-up of these patients; if initial radiographs are unrevealing, further cross-sectional imaging should be strongly considered. Although a three-phase bone scan is highly sensitive in this regard, MRI has become the study of choice at most centers.

  15. Fractures and stresses in Bone Spring sandstones. Final report

    SciT

    Warpinski, N.R.; Sattler, A.R.; Lorenz, J.C.

    This project was a collaboration between Sandia National Laboratories and the Harvey E. Yates Company (Heyco), Roswell, NM, conducted under the auspices of Department of Energy`s Oil Recovery Technology Partnership. The project applied Sandia perspectives on the effects of natural fractures, stress, and sedimentology for the stimulation and production of low permeability gas reservoirs to low permeability oil reservoirs, such as those typified by the Bone Spring sandstones of the Delaware Basin, southeast New Mexico. This report details the results and analyses obtained in 1990 from core, logs, stress, and other data taken from three additional development wells. An overallmore » summary gives results from all five wells studied in this project in 1989--1990. Most of the results presented are believed to be new information for the Bone Spring sandstones.« less

  16. Older women track and field athletes have enhanced calcaneal stiffness.

    PubMed

    Welch, J M; Rosen, C J

    2005-08-01

    Vigorous weight-bearing exercise is recommended to women as a method of osteoporosis prevention. This study examined older women athletes to see if they indeed were less likely to develop osteoporosis than those in the general population, and to investigate which factors could have contributed to these results. One hundred and thirty-nine women 40-88 years old, all competitors in a USA National Masters Track and Field Championships, volunteered for the study. Masters refers to competitors > or =40 years old. Their calcaneal stiffness (SI) was measured by a Lunar Achilles+ ultrasonometer. Subjects were also measured for height and weight, and completed a questionnaire on exercise history, diet, lifestyle factors, medical and menopausal issues, and use of hormone replacement therapy (HRT). The women, mean age 57.3 years, had an overall average SI of 99.5 (T-score = 0.04) which is equivalent to that of a 20-year-old woman and 20.8% higher than expected for women of their age. Their median SI remained not different from expected peak bone SI until the age of 70. For analysis, this cohort of women was divided into two groups: premenopausal and postmenopausal athletes. The SI of both groups was correlated with the earliest age at which they had first participated in sports or exercises that impart moderate to high strain rates to the lower limbs and with current participation in high impact track and field events. Variables correlated with SI in the general population, such as weight, HRT, previous fracture, hysterectomy, and current menopausal status, did not predict SI in this cohort. In conclusion, women competing in Masters track and field at the national level had calcaneal stiffness substantially higher than expected for women of their age in the general population, and their participation in vigorous sports and activities, either currently or at a younger age, was predictive of this association.

  17. 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.

  18. Compression Fracture of CFRP Laminates Containing Stress Intensifications.

    PubMed

    Leopold, Christian; Schütt, Martin; Liebig, Wilfried V; Philipkowski, Timo; Kürten, Jonas; Schulte, Karl; Fiedler, Bodo

    2017-09-05

    For brittle fracture behaviour of carbon fibre reinforced plastics (CFRP) under compression, several approaches exist, which describe different mechanisms during failure, especially at stress intensifications. The failure process is not only initiated by the buckling fibres, but a shear driven fibre compressive failure beneficiaries or initiates the formation of fibres into a kink-band. Starting from this kink-band further damage can be detected, which leads to the final failure. The subject of this work is an experimental investigation on the influence of ply thickness and stacking sequence in quasi-isotropic CFRP laminates containing stress intensifications under compression loading. Different effects that influence the compression failure and the role the stacking sequence has on damage development and the resulting compressive strength are identified and discussed. The influence of stress intensifications is investigated in detail at a hole in open hole compression (OHC) tests. A proposed interrupted test approach allows identifying the mechanisms of damage initiation and propagation from the free edge of the hole by causing a distinct damage state and examine it at a precise instant of time during fracture process. Compression after impact (CAI) tests are executed in order to compare the OHC results to a different type of stress intensifications. Unnotched compression tests are carried out for comparison as a reference. With this approach, a more detailed description of the failure mechanisms during the sudden compression failure of CFRP is achieved. By microscopic examination of single plies from various specimens, the different effects that influence the compression failure are identified. First damage of fibres occurs always in 0°-ply. Fibre shear failure leads to local microbuckling and the formation and growth of a kink-band as final failure mechanisms. The formation of a kink-band and finally steady state kinking is shifted to higher compressive strains

  19. Compression Fracture of CFRP Laminates Containing Stress Intensifications

    PubMed Central

    Schütt, Martin; Philipkowski, Timo; Kürten, Jonas; Schulte, Karl

    2017-01-01

    For brittle fracture behaviour of carbon fibre reinforced plastics (CFRP) under compression, several approaches exist, which describe different mechanisms during failure, especially at stress intensifications. The failure process is not only initiated by the buckling fibres, but a shear driven fibre compressive failure beneficiaries or initiates the formation of fibres into a kink-band. Starting from this kink-band further damage can be detected, which leads to the final failure. The subject of this work is an experimental investigation on the influence of ply thickness and stacking sequence in quasi-isotropic CFRP laminates containing stress intensifications under compression loading. Different effects that influence the compression failure and the role the stacking sequence has on damage development and the resulting compressive strength are identified and discussed. The influence of stress intensifications is investigated in detail at a hole in open hole compression (OHC) tests. A proposed interrupted test approach allows identifying the mechanisms of damage initiation and propagation from the free edge of the hole by causing a distinct damage state and examine it at a precise instant of time during fracture process. Compression after impact (CAI) tests are executed in order to compare the OHC results to a different type of stress intensifications. Unnotched compression tests are carried out for comparison as a reference. With this approach, a more detailed description of the failure mechanisms during the sudden compression failure of CFRP is achieved. By microscopic examination of single plies from various specimens, the different effects that influence the compression failure are identified. First damage of fibres occurs always in 0°-ply. Fibre shear failure leads to local microbuckling and the formation and growth of a kink-band as final failure mechanisms. The formation of a kink-band and finally steady state kinking is shifted to higher compressive strains

  20. Sacral Stress Fracture Mimicking Lumbar Radiculopathy in a Mounted Police Officer: Case Report and Literature Review.

    PubMed

    Bednar, Drew A; Almansoori, Khaled

    2015-10-01

    Study Design Case report and review of the literature. Objective To present a unique case of L5 radiculopathy caused by a sacral stress fracture without neurologic compression. Methods We present our case and its clinical evolution and review the available literature on similar pathologies. Results Relief of the unusual mechanical loading causing sacral stress fracture led to rapid resolution of radiculopathy. Conclusion L5 radiculopathy can be caused by a sacral stress fracture and can be relieved by simple mechanical treatment of the fracture.

  1. Polyaxial stress-dependent permeability of a three-dimensional fractured rock layer

    NASA Astrophysics Data System (ADS)

    Lei, Qinghua; Wang, Xiaoguang; Xiang, Jiansheng; Latham, John-Paul

    2017-12-01

    A study about the influence of polyaxial (true-triaxial) stresses on the permeability of a three-dimensional (3D) fractured rock layer is presented. The 3D fracture system is constructed by extruding a two-dimensional (2D) outcrop pattern of a limestone bed that exhibits a ladder structure consisting of a "through-going" joint set abutted by later-stage short fractures. Geomechanical behaviour of the 3D fractured rock in response to in-situ stresses is modelled by the finite-discrete element method, which can capture the deformation of matrix blocks, variation of stress fields, reactivation of pre-existing rough fractures and propagation of new cracks. A series of numerical simulations is designed to load the fractured rock using various polyaxial in-situ stresses and the stress-dependent flow properties are further calculated. The fractured layer tends to exhibit stronger flow localisation and higher equivalent permeability as the far-field stress ratio is increased and the stress field is rotated such that fractures are preferentially oriented for shearing. The shear dilation of pre-existing fractures has dominant effects on flow localisation in the system, while the propagation of new fractures has minor impacts. The role of the overburden stress suggests that the conventional 2D analysis that neglects the effect of the out-of-plane stress (perpendicular to the bedding interface) may provide indicative approximations but not fully capture the polyaxial stress-dependent fracture network behaviour. The results of this study have important implications for understanding the heterogeneous flow of geological fluids (e.g. groundwater, petroleum) in subsurface and upscaling permeability for large-scale assessments.

  2. Stress Wave Source Characterization: Impact, Fracture, and Sliding Friction

    NASA Astrophysics Data System (ADS)

    McLaskey, Gregory Christofer

    Rapidly varying forces, such as those associated with impact, rapid crack propagation, and fault rupture, are sources of stress waves which propagate through a solid body. This dissertation investigates how properties of a stress wave source can be identified or constrained using measurements recorded at an array of sensor sites located far from the source. This methodology is often called the method of acoustic emission and is useful for structural health monitoring and the noninvasive study of material behavior such as friction and fracture. In this dissertation, laboratory measurements of 1--300 mm wavelength stress waves are obtained by means of piezoelectric sensors which detect high frequency (10 kHz--3MHz) motions of a specimen's surface, picometers to nanometers in amplitude. Then, stress wave source characterization techniques are used to study ball impact, drying shrinkage cracking in concrete, and the micromechanics of stick-slip friction of Poly(methyl methacrylate) (PMMA) and rock/rock interfaces. In order to quantitatively relate recorded signals obtained with an array of sensors to a particular stress wave source, wave propagation effects and sensor distortions must be accounted for. This is achieved by modeling the physics of wave propagation and transduction as linear transfer functions. Wave propagation effects are precisely modeled by an elastodynamic Green's function, sensor distortion is characterized by an instrument response function, and the stress wave source is represented with a force moment tensor. These transfer function models are verified though calibration experiments which employ two different mechanical calibration sources: ball impact and glass capillary fracture. The suitability of the ball impact source model, based on Hertzian contact theory, is experimentally validated for small (˜1 mm) balls impacting massive plates composed of four different materials: aluminum, steel, glass, and PMMA. Using this transfer function approach

  3. Stress-Induced Fracturing of Reservoir Rocks: Acoustic Monitoring and μCT Image Analysis

    NASA Astrophysics Data System (ADS)

    Pradhan, Srutarshi; Stroisz, Anna M.; Fjær, Erling; Stenebråten, Jørn F.; Lund, Hans K.; Sønstebø, Eyvind F.

    2015-11-01

    Stress-induced fracturing in reservoir rocks is an important issue for the petroleum industry. While productivity can be enhanced by a controlled fracturing operation, it can trigger borehole instability problems by reactivating existing fractures/faults in a reservoir. However, safe fracturing can improve the quality of operations during CO2 storage, geothermal installation and gas production at and from the reservoir rocks. Therefore, understanding the fracturing behavior of different types of reservoir rocks is a basic need for planning field operations toward these activities. In our study, stress-induced fracturing of rock samples has been monitored by acoustic emission (AE) and post-experiment computer tomography (CT) scans. We have used hollow cylinder cores of sandstones and chalks, which are representatives of reservoir rocks. The fracture-triggering stress has been measured for different rocks and compared with theoretical estimates. The population of AE events shows the location of main fracture arms which is in a good agreement with post-test CT image analysis, and the fracture patterns inside the samples are visualized through 3D image reconstructions. The amplitudes and energies of acoustic events clearly indicate initiation and propagation of the main fractures. Time evolution of the radial strain measured in the fracturing tests will later be compared to model predictions of fracture size.

  4. Distinct hip and rearfoot kinematics in female runners with a history of tibial stress fracture.

    PubMed

    Milner, Clare E; Hamill, Joseph; Davis, Irene S

    2010-02-01

    Cross-sectional controlled laboratory study. To investigate the kinematics of the hip, knee, and rearfoot in the frontal and transverse planes in female distance runners with a history of tibial stress fracture. Tibial stress fractures are a common overuse injury in runners, accounting for up to half of all stress fractures. Abnormal kinematics of the lower extremity may contribute to abnormal musculoskeletal load distributions, leading to an increased risk of stress fractures. Thirty female runners with a history of tibial stress fracture were compared to 30 age-matched and weekly-running-distance-matched control subjects with no previous lower extremity bony injuries. Kinematic and kinetic data were collected using a motion capture system and a force platform, respectively, as subjects ran in the laboratory. Selected variables of interest were compared between the groups using a multivariate analysis of variance (MANOVA). Peak hip adduction and peak rearfoot eversion angles were greater in the stress fracture group compared to the control group. Peak knee adduction and knee internal rotation angles and all joint angles at impact peak were similar between the groups. Runners with a previous tibial stress fracture exhibited greater peak hip adduction and rearfoot eversion angles during the stance phase of running compared to healthy controls. A consequence of these mechanics may be altered load distribution within the lower extremity, predisposing individuals to stress fracture.

  5. Bilateral calcaneal epiphysiolysis in a dog.

    PubMed

    Font, J; Pèlach, M; Font, C; Cairo, J

    2013-01-01

    A case of bilateral calcaneal epiphysiolysis in a six-month-old female Dobermann Pinscher is described in this report. The absence of a traumatic event and the clinical, radiographic and histopathological abnormalities led us to the diagnosis of simultaneous bilateral epiphysiolysis of the calcaneus. A tension band and a type II transarticular external fixator were placed. The clinical signs were resolved only temporarily because of the gravity of the bone changes.

  6. Update on stress fractures in female athletes: epidemiology, treatment, and prevention.

    PubMed

    Chen, Yin-Ting; Tenforde, Adam S; Fredericson, Michael

    2013-06-01

    Stress fractures are a common type of overuse injury in athletes. Females have unique risk factors such as the female athlete triad that contribute to stress fracture injuries. We review the current literature on risk factors for stress fractures, including the role of sports participation and nutrition factors. Discussion of the management of stress fractures is focused on radiographic criteria and anatomic location and how these contribute to return to play guidelines. We outline the current recommendations for evaluating and treatment of female athlete triad. Technologies that may aid in recovery from a stress fracture including use of anti-gravity treadmills are discussed. Prevention strategies may include early screening of female athlete triad, promoting early participation in activities that improve bone health, nutritional strategies, gait modification, and orthotics.

  7. The Israeli elite infantry recruit: a model for understanding the biomechanics of stress fractures.

    PubMed

    Milgrom, C

    1989-01-01

    In a series of prospective studies among infantry recruits the biomechanics of stress fractures have been studied. In this recruit model bone geometry and the natural shock absorbers of the body have been found to be related to stress fracture morbidity. Using the technique of accelerometry in this model, it has been shown that in the fatigue state shock absorption decreases, resulting in an increase in the amplitude of vertical accelerations that propagate up the skeleton at heel strike. Experiments to study the possibility of lowering stress fracture morbidity in this model by means of viscoelastic orthotics have been successful only in the case of femoral and metatarsal stress fractures among certain subpopulations. Stress fracture management in this model has been improved by early detection and by treatment regimens according to a protocol that emphasizes limited rest periods to allow healing to take place rather than judging recovery by pain levels.

  8. Stress fracture risk factors in female football players and their clinical implications

    PubMed Central

    Warden, Stuart J; Creaby, Mark W; Bryant, Adam L; Crossley, Kay M

    2007-01-01

    A stress fracture represents the inability of the skeleton to withstand repetitive bouts of mechanical loading, which results in structural fatigue, and resultant signs and symptoms of localised pain and tenderness. Reports of stress fractures in female football players are not prevalent; however, they are probably under‐reported and their importance lies in the morbidity that they cause in terms of time lost from participation. By considering risk factors for stress fractures in female football players it may be possible to reduce the impact of these troublesome injuries. Risk factors for stress fractures in female football players include intrinsic risk factors such as gender, endocrine, nutritional, physical fitness and neuromusculoskeletal factors, as well as extrinsic risk factors such as training programme, equipment and environmental factors. This paper discusses these risk factors and their implications in terms of developing prevention and management strategies for stress fractures in female football players. PMID:17584950

  9. Stress fracture risk factors in female football players and their clinical implications.

    PubMed

    Warden, Stuart J; Creaby, Mark W; Bryant, Adam L; Crossley, Kay M

    2007-08-01

    A stress fracture represents the inability of the skeleton to withstand repetitive bouts of mechanical loading, which results in structural fatigue, and resultant signs and symptoms of localised pain and tenderness. Reports of stress fractures in female football players are not prevalent; however, they are probably under-reported and their importance lies in the morbidity that they cause in terms of time lost from participation. By considering risk factors for stress fractures in female football players it may be possible to reduce the impact of these troublesome injuries. Risk factors for stress fractures in female football players include intrinsic risk factors such as gender, endocrine, nutritional, physical fitness and neuromusculoskeletal factors, as well as extrinsic risk factors such as training programme, equipment and environmental factors. This paper discusses these risk factors and their implications in terms of developing prevention and management strategies for stress fractures in female football players.

  10. Virtual stress testing of fracture stability in soldiers with severely comminuted tibial fractures.

    PubMed

    Petfield, Joseph L; Hayeck, Garry T; Kopperdahl, David L; Nesti, Leon J; Keaveny, Tony M; Hsu, Joseph R

    2017-04-01

    Virtual stress testing (VST) provides a non-invasive estimate of the strength of a healing bone through a biomechanical analysis of a patient's computed tomography (CT) scan. We asked whether VST could improve management of patients who had a tibia fracture treated with external fixation. In a retrospective case-control study of 65 soldier-patients who had tibia fractures treated with an external fixator, we performed VST utilizing CT scans acquired prior to fixator removal. The strength of the healing bone and the amount of tissue damage after application of an overload were computed for various virtual loading cases. Logistic regression identified computed outcomes with the strongest association to clinical events related to nonunion within 2 months after fixator removal. Clinical events (n = 9) were associated with a low tibial strength for compression loading (p < 0.05, AUC = 0.74) or a low proportion of failed cortical bone tissue for torsional loading (p < 0.005, AUC = 0.84). Using post-hoc thresholds of a compressive strength of four times body-weight and a proportional of failed cortical bone tissue of 5%, the test identified all nine patients who failed clinically (100% sensitivity; 40.9% positive predictive value) and over three fourths of those (43 of 56) who progressed to successful healing (76.8% specificity; 100% negative predictive value). In this study, VST identified all patients who progressed to full, uneventful union after fixator removal; thus, we conclude that this new test has the potential to provide a quantitative, objective means of identifying tibia-fracture patients who can safely resume weight bearing. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:805-811, 2017. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  11. Overuse injuries: tendinopathies, stress fractures, compartment syndrome, and shin splints.

    PubMed

    Wilder, Robert P; Sethi, Shikha

    2004-01-01

    Approximately 50% of all sports injuries are secondary to overuse and result from repetitive microtrauma that causes local tissue damage. Injuries are most likely with changes in mode, intensity, or duration of training and can accumulate before symptoms appear. Intrinsic factors contributing to injuries are individual bio-mechanical abnormalities such as malalignments, muscle imbalance, inflexibility, weakness, and instability. Contributing extrinsic (avoidable) factors include poor technique, improper equipment, and improper changes in duration or frequency of activity. Injuries are often related to biomechanical abnormalities removed from the specific injury site, requiring evaluation of the entire kinetic chain. This article discusses common overuse injuries of the lower leg, ankle, and foot: tendinopathies, stress fractures, chronic exertional compartment syndrome, and shin splints.

  12. A Discrete Fracture Network Model with Stress-Driven Nucleation and Growth

    NASA Astrophysics Data System (ADS)

    Lavoine, E.; Darcel, C.; Munier, R.; Davy, P.

    2017-12-01

    The realism of Discrete Fracture Network (DFN) models, beyond the bulk statistical properties, relies on the spatial organization of fractures, which is not issued by purely stochastic DFN models. The realism can be improved by injecting prior information in DFN from a better knowledge of the geological fracturing processes. We first develop a model using simple kinematic rules for mimicking the growth of fractures from nucleation to arrest, in order to evaluate the consequences of the DFN structure on the network connectivity and flow properties. The model generates fracture networks with power-law scaling distributions and a percentage of T-intersections that are consistent with field observations. Nevertheless, a larger complexity relying on the spatial variability of natural fractures positions cannot be explained by the random nucleation process. We propose to introduce a stress-driven nucleation in the timewise process of this kinematic model to study the correlations between nucleation, growth and existing fracture patterns. The method uses the stress field generated by existing fractures and remote stress as an input for a Monte-Carlo sampling of nuclei centers at each time step. Networks so generated are found to have correlations over a large range of scales, with a correlation dimension that varies with time and with the function that relates the nucleation probability to stress. A sensibility analysis of input parameters has been performed in 3D to quantify the influence of fractures and remote stress field orientations.

  13. Risk Stratification of Stress Fractures and Prediction of Return to Duty

    DTIC Science & Technology

    2015-12-01

    enrollment. In study Task 1 we aim to determine the sex- and race -ethnicity-specific bone traits that may contribute to stress fracture risk in military...SUBJECT TERMS bone microarchitecture, HRpQCT, race , gender, sex, bone mineral density, vBMD, bone geometry, stress fracture 16. SECURITY...sectional study aimed at identifying the bone properties that may be related to the well-known sex and race /ethnicity differences in risk for stress

  14. Dynamic Response in Transient Stress-Field Behavior Induced by Hydraulic Fracturing

    NASA Astrophysics Data System (ADS)

    Jenkins, Andrew

    Hydraulic fracturing is a technique which is used to exploit geologic features and subsurface properties in an effort to increase production in low-permeability formations. The process of hydraulic fracturing provides a greater surface contact area between the producing formation and the wellbore and thus increases the amount of recoverable hydrocarbons from within the reservoir. The use of this stimulation technique has brought on massive applause from the industry due to its widespread success and effectiveness, however the dynamic processes that take part in the development of hydraulic fractures is a relatively new area of research with respect to the massive scale operations that are seen today. The process of hydraulic fracturing relies upon understanding and exploiting the in-situ stress distribution throughout the area of study. These in-situ stress conditions are responsible for directing fracture orientation and propagation paths throughout the period of injection. The relative magnitude of these principle stresses is key in developing a successful stimulation plan. In horizontal well plan development the interpretation of stress within the reservoir is required for determining the azimuth of the horizontal well path. These horizontal laterals are typically oriented in a manner such that the well path lies parallel to the minimum horizontal stress. This allows for vertical fractures to develop transversely to the wellbore, or normal to the least principle stress without the theoretical possibility of fractures overlapping, creating the most efficient use of the fluid energy during injection. The orientation and magnitude of these in-situ stress fields however can be dynamic, controlled by the subsequent fracture propagation and redistribution of the surrounding stresses. That is, that as the fracture propagates throughout the reservoir, the relative stress fields surrounding the fractures may see a shift and deviate from their original direction or

  15. Fragility fractures of the ankle in the elderly: Open reduction and internal fixation versus tibio-talo-calcaneal nailing: Short-term results of a prospective randomized-controlled study.

    PubMed

    Georgiannos, D; Lampridis, V; Bisbinas, I

    2017-02-01

    The management of ankle fractures in the elderly remains unpredictable, secondary to their various co-morbidities. Although tibiotalocalcaneal (TTC) nailing has been an effective option for ankle arthrodesis due to ankle arthritis or Charcot arthropathy there are few reports regarding the use of TTC nail for the treatment of ankle fractures. Aim of this study was to compare the results of ORIF versus TTC nailing for the treatment of unstable ankle fractures in the elderly. We hypothesized that the elderly may benefit from TTC nailing, as it allows the patient to be mobilized immediately after surgery and minimizes the risk of wound or bone problems. This was a prospective, randomized-controlled, comparative study. Between 2009 and 2015, 43 patients were treated with a TTC nail (Group A) and 44 with ORIF (Group B). The Olerud-Molander ankle score was obtained and intraoperative-postoperative complications, length of hospital stay, mobility status and reoperation rate were recorded. The nail fixation was performed with the TrigenR hindfoot nail after closed reduction. ORIF was performed, using a 1/3 tubular plate and 3.5mm screws for the lateral malleolus and two 4.0 mm cannulated screws for the medial. Mortality rate at one year was 13.9% for Group A and 18.1% for Group B. Mean follow-up was 14 months (12-18m). There were no intraoperative complications. Three complications in Group A (8.1%) and twelve (33.3%) in Group B were encountered postoperatively (p<0.05). There was significant shorter hospital stay in Group A (5.2±3.1d) than in Group B (8.4±5.2d). In Group A, 28 patients returned to their pre-injury mobility status (75.6%) while 9 declined one level of the mobility scale (24.3%). In Group B, 26 patients remained at the same mobility level (72.2%) and 10 declined one level (27.7%). There was no significant difference between the postoperative OMAS scores in the two Groups (56.9±9.85 and 56.6±9.3 respectively). We believe that TTC nailing is a safe and

  16. The Young's Modulus, Fracture Stress, and Fracture Strain of Gellan Hydrogels Filled with Whey Protein Microparticles.

    PubMed

    Lam, Cherry Wing Yu; Ikeda, Shinya

    2017-05-01

    Texture modifying abilities of whey protein microparticles are expected to be dependent on pH during heat-induced aggregation of whey protein in the microparticulation process. Therefore, whey protein microparticles were prepared at either pH 5.5 or 6.8 and their effects on small and large deformation properties of gellan gels containing whey protein microparticles as fillers were investigated. The majority of whey protein microparticles had diameters around 2 μm. Atomic force microscopy images showed that whey protein microparticles prepared at pH 6.8 partially collapsed and flatted by air-drying, while those prepared at pH 5.5 did not. The Young's modulus of filled gels adjusted to pH 5.5 decreased by the addition of whey protein microparticles, while those of filled gels adjusted to pH 6.8 increased with increasing volume fraction of filler particles. These results suggest that filler particles were weakly bonded to gel matrices at pH 5.5 but strongly at pH 6.8. Whey protein microparticles prepared at pH 5.5 showed more enhanced increases in the Young's modulus than those prepared at pH 6.8 at volume fractions between 0.2 and 0.4, indicating that microparticles prepared at pH 5.5 were mechanically stronger. The fracture stress of filled gels showed trends somewhat similar to those of the Young's modulus, while their fracture strains decreased by the addition of whey protein microparticles in all examined conditions, indicating that the primary effect of these filler particles was to enhance the brittleness of filled gels. © 2017 Institute of Food Technologists®.

  17. Medial tibial plateau morphology and stress fracture location: A magnetic resonance imaging study.

    PubMed

    Yukata, Kiminori; Yamanaka, Issei; Ueda, Yuzuru; Nakai, Sho; Ogasa, Hiroyoshi; Oishi, Yosuke; Hamawaki, Jun-Ichi

    2017-06-18

    To determine the location of medial tibial plateau stress fractures and its relationship with tibial plateau morphology using magnetic resonance imaging (MRI). A retrospective review of patients with a diagnosis of stress fracture of the medial tibial plateau was performed for a 5-year period. Fourteen patients [three female and 11 male, with an average age of 36.4 years (range, 15-50 years)], who underwent knee MRI, were included. The appearance of the tibial plateau stress fracture and the geometry of the tibial plateau were reviewed and measured on MRI. Thirteen of 14 stress fractures were linear, and one of them stellated on MRI images. The location of fractures was classified into three types. Three fractures were located anteromedially (AM type), six posteromedially (PM type), and five posteriorly (P type) at the medial tibial plateau. In addition, tibial posterior slope at the medial tibial plateau tended to be larger when the fracture was located more posteriorly on MRI. We found that MRI showed three different localizations of medial tibial plateau stress fractures, which were associated with tibial posterior slope at the medial tibial plateau.

  18. Medial tibial plateau morphology and stress fracture location: A magnetic resonance imaging study

    PubMed Central

    Yukata, Kiminori; Yamanaka, Issei; Ueda, Yuzuru; Nakai, Sho; Ogasa, Hiroyoshi; Oishi, Yosuke; Hamawaki, Jun-ichi

    2017-01-01

    AIM To determine the location of medial tibial plateau stress fractures and its relationship with tibial plateau morphology using magnetic resonance imaging (MRI). METHODS A retrospective review of patients with a diagnosis of stress fracture of the medial tibial plateau was performed for a 5-year period. Fourteen patients [three female and 11 male, with an average age of 36.4 years (range, 15-50 years)], who underwent knee MRI, were included. The appearance of the tibial plateau stress fracture and the geometry of the tibial plateau were reviewed and measured on MRI. RESULTS Thirteen of 14 stress fractures were linear, and one of them stellated on MRI images. The location of fractures was classified into three types. Three fractures were located anteromedially (AM type), six posteromedially (PM type), and five posteriorly (P type) at the medial tibial plateau. In addition, tibial posterior slope at the medial tibial plateau tended to be larger when the fracture was located more posteriorly on MRI. CONCLUSION We found that MRI showed three different localizations of medial tibial plateau stress fractures, which were associated with tibial posterior slope at the medial tibial plateau. PMID:28660141

  19. Outcomes of Surgical Treatment for Anterior Tibial Stress Fractures in Athletes: A Systematic Review.

    PubMed

    Chaudhry, Zaira S; Raikin, Steven M; Harwood, Marc I; Bishop, Meghan E; Ciccotti, Michael G; Hammoud, Sommer

    2017-12-01

    Although most anterior tibial stress fractures heal with nonoperative treatment, some may require surgical management. To our knowledge, no systematic review has been conducted regarding surgical treatment strategies for the management of chronic anterior tibial stress fractures from which general conclusions can be drawn regarding optimal treatment in high-performance athletes. This systematic review was conducted to evaluate the surgical outcomes of anterior tibial stress fractures in high-performance athletes. Systematic review; Level of evidence, 4. In February 2017, a systematic review of the PubMed, MEDLINE, Cochrane, SPORTDiscus, and CINAHL databases was performed to identify studies that reported surgical outcomes for anterior tibial stress fractures. Articles meeting the inclusion criteria were screened, and reported outcome measures were documented. A total of 12 studies, published between 1984 and 2015, reporting outcomes for the surgical treatment of anterior tibial stress fractures were included in this review. All studies were retrospective case series. Collectively, surgical outcomes for 115 patients (74 males; 41 females) with 123 fractures were evaluated in this review. The overall mean follow-up was 23.3 months. The most common surgical treatment method reported in the literature was compression plating (n = 52) followed by drilling (n = 33). Symptom resolution was achieved in 108 of 123 surgically treated fractures (87.8%). There were 32 reports of complications, resulting in an overall complication rate of 27.8%. Subsequent tibial fractures were reported in 8 patients (7.0%). Moreover, a total of 17 patients (14.8%) underwent a subsequent procedure after their initial surgery. Following surgical treatment for anterior tibial stress fracture, 94.7% of patients were able to return to sports. The available literature indicates that surgical treatment of anterior tibial stress fractures is associated with a high rate of symptom resolution and return

  20. Greater Polar Moment of Inertia at the Tibia in Athletes Who Develop Stress Fractures.

    PubMed

    Weidauer, Lee A; Binkley, Teresa; Vukovich, Matt; Specker, Bonny

    2014-07-01

    Several previous investigations have determined potential risk factors for stress fractures in athletes and military personnel. To determine factors associated with the development of stress fractures in female athletes. Case-control study; Level of evidence, 3. A total of 88 female athletes (cross-country, n = 29; soccer, n = 15; swimming, n = 9; track and field, n = 14; volleyball, n = 12; and basketball, n = 9) aged 18 to 24 years were recruited to participate in a longitudinal bone study and had their left distal tibia at the 4%, 20%, and 66% sites scanned by peripheral quantitative computed tomography (pQCT). Patients included 23 athletes who developed stress fractures during the following year (cases). Whole body, hip, and spine scans were obtained using dual-energy x-ray absorptiometry (DXA). Analysis of covariance was used to determine differences in bone parameters between cases and controls after adjusting for height, lower leg length, lean mass, fat mass, and sport. No differences were observed between cases and controls in any of the DXA measurements. Cases had significantly greater unadjusted trabecular bone mineral content (BMC), greater polar moment of inertia (PMI) at the 20% site, and greater cortical BMC at the 66% site; however, after adjusting for covariates, the differences became nonsignificant. When analyses were repeated using all individuals who had ever had a stress fracture as cases (n = 31) and after controlling for covariates, periosteal circumference was greater in the cases than the controls (71.1 ± 0.7 vs 69.4 ± 0.5 mm, respectively; P = .04). A history of stress fractures is associated with larger bones. These findings are important because larger bones were previously reported to be protective against fractures and stress fractures, but study findings indicate that may not always be true. One explanation could be that individuals who sustain stress fractures have greater loading that results in greater periosteal circumference

  1. Range limitation in hip internal rotation and fifth metatarsal stress fractures (Jones fracture) in professional football players.

    PubMed

    Saita, Yoshitomo; Nagao, Masashi; Kawasaki, Takayuki; Kobayashi, Yohei; Kobayashi, Keiji; Nakajima, Hiroki; Takazawa, Yuji; Kaneko, Kazuo; Ikeda, Hiroshi

    2017-04-25

    To identify unknown risk factors associated with fifth metatarsal stress fracture (Jones fracture). A case-controlled study was conducted among male Japanese professional football (soccer) players with (N = 20) and without (N = 40) a history of Jones fracture. Injury history and physical examination data were reviewed, and the two groups were compared. Univariate and multivariate logistic regression controlling for age, leg dominance and body mass index were used to obtain odds ratios (ORs) and 95% confidence intervals (CIs) to describe the association between physical examination data and the presence or absence of Jones fractures. From 2000 to 2014, among 162 professional football club players, 22 (13.6%; 21 Asians and one Caucasian) had a history of Jones fracture. Thirteen out of 22 (60%) had a Jones fracture in their non-dominant leg. The mean range of hip internal rotation (HIR) was restricted in players with a history of Jones fracture [25.9° ± 7.5°, mean ± standard deviation (SD)] compared to those without (40.4° ± 11.1°, P < 0.0001). Logistic regression analyses demonstrated that HIR limitation increased the risk of a Jones fracture (OR = 3.03, 95% CI 1.45-6.33, P = 0.003). Subgroup analysis using data prior to Jones fracture revealed a causal relationship, such that players with a restriction of HIR were at high risk of developing a Jones fracture [Crude OR (95% CI) = 6.66 (1.90-23.29), P = 0.003, Adjusted OR = 9.91 (2.28-43.10), P = 0.002]. In addition, right HIR range limitation increased the risks of developing a Jones fracture in the ipsilateral and the contralateral feet [OR = 3.11 (1.35-7.16) and 2.24 (1.22-4.12), respectively]. Similarly, left HIR range limitation increased the risks in the ipsilateral or the contralateral feet [OR (95% CI) = 4.88 (1.56-15.28) and 2.77 (1.08-7.08), respectively]. The restriction of HIR was associated with an increased risk of developing a Jones fracture. Since the HIR range is a

  2. The impact of in-situ stress and outcrop-based fracture geometry on hydraulic aperture and upscaled permeability in fractured reservoirs

    NASA Astrophysics Data System (ADS)

    Bisdom, Kevin; Bertotti, Giovanni; Nick, Hamidreza M.

    2016-10-01

    Aperture has a controlling impact on porosity and permeability and is a source of uncertainty in modeling of naturally fractured reservoirs. This uncertainty results from difficulties in accurately quantifying aperture in the subsurface and from a limited fundamental understanding of the mechanical and diagenetic processes that control aperture. In the absence of cement bridges and high pore pressure, fractures in the subsurface are generally considered to be closed. However, experimental work, outcrop analyses and subsurface data show that some fractures remain open, and that aperture varies even along a single fracture. However, most fracture flow models consider constant apertures for fractures. We create a stress-dependent heterogeneous aperture by combining Finite Element modeling of discrete fracture networks with an empirical aperture model. Using a modeling approach that considers fractures explicitly, we quantify equivalent permeability, i.e. combined matrix and stress-dependent fracture flow. Fracture networks extracted from a large outcropping pavement form the basis of these models. The results show that the angle between fracture strike and σ1 has a controlling impact on aperture and permeability, where hydraulic opening is maximum for an angle of 15°. At this angle, the fracture experiences a minor amount of shear displacement that allows the fracture to remain open even when fluid pressure is lower than the local normal stress. Averaging the heterogeneous aperture to scale up permeability probably results in an underestimation of flow, indicating the need to incorporate full aperture distributions rather than simplified aperture models in reservoir-scale flow models.

  3. Stress analysis of implant-bone fixation at different fracture angle

    NASA Astrophysics Data System (ADS)

    Izzawati, B.; Daud, R.; Afendi, M.; Majid, MS Abdul; Zain, N. A. M.; Bajuri, Y.

    2017-10-01

    Internal fixation is a mechanism purposed to maintain and protect the reduction of a fracture. Understanding of the fixation stability is necessary to determine parameters influence the mechanical stability and the risk of implant failure. A static structural analysis on a bone fracture fixation was developed to simulate and analyse the biomechanics of a diaphysis shaft fracture with a compression plate and conventional screws. This study aims to determine a critical area of the implant to be fractured based on different implant material and angle of fracture (i.e. 0°, 30° and 45°). Several factors were shown to influence stability to implant after surgical. The stainless steel, (S. S) and Titanium, (Ti) screws experienced the highest stress at 30° fracture angle. The fracture angle had a most significant effect on the conventional screw as compared to the compression plate. The stress was significantly higher in S.S material as compared to Ti material, with concentrated on the 4th screw for all range of fracture angle. It was also noted that the screws closest to the intense concentration stress areas on the compression plate experienced increasing amounts of stress. The highest was observed at the screw thread-head junction.

  4. Bilateral femoral neck stress fractures in military recruits with unilateral hip pain.

    PubMed

    Moo, Ing How; Lee, Y H D; Lim, K K; Mehta, K V

    2016-10-01

    Femoral neck stress fractures are rare and can be easily missed and failure to diagnose these injuries early can lead to avascular necrosis, malunion and osteoarthritis. It is important to have a high index of suspicion for femoral neck stress fractures in military recruits. We present three cases of bilateral femoral neck fractures in military recruits, all presenting with unilateral hip symptoms and signs. All the asymptomatic contralateral hips had femoral neck stress fractures diagnosed by screening MRI. Tension type and displaced femoral neck fractures were treated surgically. All the fractures managed healing without complications. Military recruits with unilateral groin pain should have an early referral for MRI hip to rule out femoral neck stress fractures and those military personnel with ipsilateral femoral neck fracture should have MRI of the contralateral hip. Two of the patients had vitamin D deficiency, of which one had elevated parathyroid hormones and low bone mineral density. Our case series highlights the significance of vitamin D deficiency among military recruits. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  5. Stress fracture as a complication of autogenous bone graft harvest from the distal tibia.

    PubMed

    Chou, Loretta B; Mann, Roger A; Coughlin, Michael J; McPeake, William T; Mizel, Mark S

    2007-02-01

    Autogenous bone graft from the distal tibia provides cancellous bone graft for foot and ankle operations, and it has osteogenic and osteoconductive properties. The site is in close proximity to the foot and ankle, and published retrospective studies show low morbidity from the procedure. One-hundred autografts were obtained from the distal tibia between 2000 and 2003. In four cases the distal tibial bone graft harvest resulted in a stress fracture. There were three women and one man. The average time of diagnosis of the stress fracture from the operation was 1.8 months. All stress fractures healed with a short course (average 2.4 months) of cast immobilization. This study demonstrated that a stress fracture from the donor site of autogenous bone graft of the distal tibia occurs and can be successfully treated nonoperatively.

  6. Bone Geometry as a Predictor of Tissue Fragility and Stress Fracture Risk

    DTIC Science & Technology

    2004-10-01

    eferences ........................................................................ 11 A ppendices ...School of Medicine, New York NY Stress fractures occur among persons with normal bones, no acute injury, and are most common among elite runners and

  7. Manubrial stress fractures diagnosed on MRI: report of two cases and review of the literature.

    PubMed

    Baker, Jonathan C; Demertzis, Jennifer L

    2016-06-01

    In contrast to widely-reported sternal insufficiency fractures, stress fractures of the sternum from overuse are extremely rare. Of the 5 cases of sternal stress fracture published in the English-language medical literature, 3 were in the sternal body and only 2 were in the manubrium. We describe two cases of manubrial stress fracture related to golf and weightlifting, and present the first report of the MR findings of this injury. In each of these cases, the onset of pain was atraumatic, insidious, and associated with increased frequency of athletic activity. Imaging was obtained because of clinical diagnostic uncertainty. On MRI, each patient had a sagittally oriented stress fracture of the lateral manubrium adjacent to the first rib synchondrosis. Both patients had resolution of pain after a period of rest, with subsequent successful return to their respective activities. One patient had a follow-up MRI, which showed resolution of the manubrial marrow edema and fracture line. Based on the sternal anatomy and MR findings, we hypothesize that this rare injury might be caused by repetitive torque of the muscle forces on the first costal cartilage and manubrium, and propose that MRI might be an effective means of diagnosing manubrial stress fracture.

  8. Value of lateral blood pool imaging in patients with suspected stress fractures of the tibia.

    PubMed

    Mohan, Hosahalli K; Clarke, Susan E M; Centenara, Martin; Lucarelli, Amanda; Baron, Daniel; Fogelman, Ignac

    2011-03-01

    To critically evaluate the use of lateral blood pool imaging in athletes with lower limb pain and with a clinical suspicion of stress fracture. Two experienced nuclear medicine physicians evaluated 3-phase bone scans using 99mTc-methylene diphosphonate performed in 50 consecutive patients referred from a specialist sports injury clinic for suspected tibial stress fracture. The vascularity to the tibia as seen on the blood pool (second phase) images in the anterior/posterior views was compared with the lateral/medial view assessments. Stress fractures were presumed to be present when on the delayed images (third phase) there was a focal or fusiform area of increased tracer uptake involving the tibial cortex. Shin splints which are a recognized cause of lower limb pain in athletes mimicking stress fracture were diagnosed if increased tracer uptake was seen extending along the posterior tibial surface with no significant focal or fusiform area of uptake within this. Inter-reviewer agreement for the assessment of vascularity was also assessed using Cohen's Kappa scores. Twenty-four stress fractures in 24 patients and 66 shin splints in 40 patients were diagnosed. In 18 patients stress fracture and shin splints coexisted. In 10 patients no tibial pathology was identified. Of the 24 patients diagnosed with stress fractures, lateral/medial blood pool imaging was superior in the assessment of blood pool activity (P < 0.001) identifying increased vascularity in 21 cases compared with the anterior/posterior views positive in only 11 cases. The inter-reviewer agreement was near perfect for lateral/medial views, κ = 0.86 while very good for anterior/posterior views, κ = 0.68. In patients with suspected tibial stress fractures, lateral views of the tibia provide the optimal method for evaluation of vascularity. Prospective studies with quantitative or semi-quantitative assessment of skeletal vascularity could provide supplementary information relating to the pathophysiology

  9. Step test performance and risk of stress fractures among female army trainees.

    PubMed

    Cowan, David N; Bedno, Sheryl A; Urban, Nadia; Lee, Dara S; Niebuhr, David W

    2012-06-01

    Stress fractures and other musculoskeletal injuries are major sources of morbidity among female military trainees. Several risk factors have been postulated, particularly pre-existing fitness, usually assessed with post-entry run time for ≥ 1.0 mile. Physical fitness is not formally evaluated prior to Army entry. If a valid and simple test that identified women at increased risk of stress fracture were available and could be applied prior to entry, it would facilitate cost-benefit studies of deferral or interventions. These analyses were undertaken to determine if a 5-minute step test conducted before entry identified women at increased risk. A prospective study was conducted of weight-qualified women entering the Army in 2005-2006, with analyses completed in 2011. At the pre-entry examination, information was collected on age, BMI, smoking, race, and activity level. Everyone took the step test. All outpatient medical encounters were captured, and stress fractures and other musculoskeletal injuries identified. Women with stress fractures and those with other musculoskeletal injuries were evaluated separately. 1568 women were included in the study; 109 developed stress fractures and 803 other musculoskeletal injury. Women who failed the step test had a 76% higher stress fracture incidence and a 35% higher incidence of other musculoskeletal injuries. There was effect modification between age and test failure for stress fracture. A step test that can be administered before military entry identifies women with increased incidence of stress fracture and other musculoskeletal injury. This test could be used pre-entry to defer or target high-risk recruits for tailored fitness training before or after military entrance. Copyright © 2012 American Journal of Preventive Medicine. All rights reserved.

  10. Risk factors for stress fracture among young female cross-country runners.

    PubMed

    Kelsey, Jennifer L; Bachrach, Laura K; Procter-Gray, Elizabeth; Nieves, Jeri; Greendale, Gail A; Sowers, Maryfran; Brown, Byron W; Matheson, Kim A; Crawford, Sybil L; Cobb, Kristin L

    2007-09-01

    To identify risk factors for stress fracture among young female distance runners. Participants were 127 competitive female distance runners, aged 18-26, who provided at least some follow-up data in a randomized trial among 150 runners of the effects of oral contraceptives on bone health. After completing a baseline questionnaire and undergoing bone densitometry, they were followed an average of 1.85 yr. Eighteen participants had at least one stress fracture during follow-up. Baseline characteristics associated (P<0.10) in multivariate analysis with stress fracture occurrence were one or more previous stress fractures (rate ratio [RR] [95% confidence interval]=6.42 (1.80-22.87), lower whole-body bone mineral content (RR=2.70 [1.26-5.88] per 1-SD [293.2 g] decrease), younger chronologic age (RR=1.42 [1.05-1.92] per 1-yr decrease), lower dietary calcium intake (RR=1.11 [0.98-1.25] per 100-mg decrease), and younger age at menarche (RR=1.92 [1.15-3.23] per 1-yr decrease). Although not statistically significant, a history of irregular menstrual periods was also associated with increased risk (RR=3.41 [0.69-16.91]). Training-related factors did not affect risk. The results of this and other studies indicate that risk factors for stress fracture among young female runners include previous stress fractures, lower bone mass, and, although not statistically significant in this study, menstrual irregularity. More study is needed of the associations between stress fracture and age, calcium intake, and age at menarche. Given the importance of stress fractures to runners, identifying preventive measures is of high priority.

  11. Identification of natural fractures and in situ stress at Rantau Dedap geothermal field

    NASA Astrophysics Data System (ADS)

    Artyanto, Andika; Sapiie, Benyamin; Idham Abdullah, Chalid; Permana Sidik, Ridwan

    2017-12-01

    Rantau Dedap Area is a geothermal field which is located in Great Sumatra Fault (GSF). The fault and fracture are main factor in the permeability of the geothermal system. However, not all faults and fractures have capability of to flow the fluids. Borehole image log is depiction of the borehole conditions, it is used to identify the natural fractures and drilling induced fracture. Both of them are used to identify the direction of the fracture, direction of maximum horizontal stress (SHmax), and geomechanics parameters. The natural fractures are the results of responses to stress on a rock and permeability which controlling factor in research area. Breakouts is found in this field as a trace of drilling induced fracture due to in situ stress work. Natural fractures are strongly clustered with true strike trending which first, second, and third major direction are N170°E - N180°E (N-S), N60°E - N70°E (NE-SW), and N310°E - N320°E (NW-SE), while the dominant dip is 80° -90°. Based on borehole breakout analysis, maximum horizontal stress orientation is identified in N162°E - N204°E (N-S) and N242°E (NE-SW) direction. It’s constantly similar with regional stress which is affected by GSF. Several parameters have been identified and analyzed are SHmax, SHmin, and Sy. It can be concluded that Rantau Dedap Geothermal Field is affected by strike-slip regime. The determination of in situ stress and natural fractures are important to study the pattern of permeability which is related to the fault in reservoir of this field.

  12. Immediate effects of modified landing pattern on a probabilistic tibial stress fracture model in runners.

    PubMed

    Chen, T L; An, W W; Chan, Z Y S; Au, I P H; Zhang, Z H; Cheung, R T H

    2016-03-01

    Tibial stress fracture is a common injury in runners. This condition has been associated with increased impact loading. Since vertical loading rates are related to the landing pattern, many heelstrike runners attempt to modify their footfalls for a lower risk of tibial stress fracture. Such effect of modified landing pattern remains unknown. This study examined the immediate effects of landing pattern modification on the probability of tibial stress fracture. Fourteen experienced heelstrike runners ran on an instrumented treadmill and they were given augmented feedback for landing pattern switch. We measured their running kinematics and kinetics during different landing patterns. Ankle joint contact force and peak tibial strains were estimated using computational models. We used an established mathematical model to determine the effect of landing pattern on stress fracture probability. Heelstrike runners experienced greater impact loading immediately after landing pattern switch (P<0.004). There was an increase in the longitudinal ankle joint contact force when they landed with forefoot (P=0.003). However, there was no significant difference in both peak tibial strains and the risk of tibial stress fracture in runners with different landing patterns (P>0.986). Immediate transitioning of the landing pattern in heelstrike runners may not offer timely protection against tibial stress fracture, despite a reduction of impact loading. Long-term effects of landing pattern switch remains unknown. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Bilateral periprosthetic tibial stress fracture after total knee arthroplasty: A case report.

    PubMed

    Ozdemir, Guzelali; Azboy, Ibrahim; Yilmaz, Baris

    2016-01-01

    Periprosthetic fractures around the knee after total knee arthroplasty can be seen in the femur, tibia and patella. The tibial fractures are rare cases. Our case with bilateral tibial stress fracture developed after total knee arthroplasty (TKA) is the first of its kind in the literature. 75-year-old male patient with bilateral knee osteoarthritis had not benefited from conservative treatment methods previously applied. Left TKA was applied. In the second month postoperatively, periprosthetic tibial fracture was identified and osteosynthesis was implemented with locked tibia proximal plate-screw. Bone union in 12 weeks was observed in his follow-ups. After 15 months of his first operation, TKA was applied to the right knee. Postoperatively in the second month, as in the first operation, periprosthetic tibial fracture was detected. Osteosynthesis with locking plate-screw was applied and union in 12 weeks was observed in his follow-up. He was seen mobilized independently and without support in the last control of the case made in the 24th month after the second operation. The number of TKA applications is expected to increase in the future. The incidence of periprosthetic fractures should also be expected to increase in these cases. Periprosthetic tibial fractures after TKA are rarely seen. The treatment of periprosthetic fractures around the knee after TKA can be difficult. In the case of persistent pain in the upper end of the tibia after the surgery, stress fracture should be considered. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  14. Comparative biomechanical evaluation of mono-cortical osteosynthesis systems for condylar fractures using photoelastic stress analysis.

    PubMed

    Christopoulos, Panos; Stathopoulos, Panagiotis; Alexandridis, Constantinos; Shetty, Vivek; Caputo, Angelo

    2012-10-01

    Fractures of the condyle account for 20-30% of all mandibular fractures, and are therefore one of the most common facial injuries. Precise evaluation of the mechanical stresses that develop in a fractured mandible is essential, particularly for the testing of systems currently used for stabilisation of the condylar fragment. Photoelastic stress analysis can be used to visualise alterations in the strain that is induced in the mandible by a fracture, and in the osteosynthesis materials used to stabilise it. This method, used on currently used osteosynthesis materials, showed that stabilisation of a subcondylar fracture with a single miniplate does not provide enough stability, whereas the use of two miniplates - properly positioned - offers sufficient stability in all loading conditions. A microplate may be used as a tension-resisting plate with equally good results. Copyright © 2011 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  15. Surgical treatment of refractory tibial stress fractures in elite dancers: a case series.

    PubMed

    Miyamoto, Ryan G; Dhotar, Herman S; Rose, Donald J; Egol, Kenneth

    2009-06-01

    Treatment of tibial stress fractures in elite dancers is centered on rest and activity modification. Surgical intervention in refractory cases has important implications affecting the dancers' careers. Refractory tibial stress fractures in dancers can be treated successfully with drilling and bone grafting or intramedullary nailing. Case series; Level of evidence, 4. Between 1992 and 2006, 1757 dancers were evaluated at a dance medicine clinic; 24 dancers (1.4%) had 31 tibial stress fractures. Of that subset, 7 (29.2%) elite dancers with 8 tibial stress fractures were treated operatively with either intramedullary nailing or drilling and bone grafting. Six of the patients were followed up closely until they were able to return to dance. One patient was available only for follow-up phone interview. Data concerning their preoperative treatment regimens, operative procedures, clinical union, radiographic union, and time until return to dance were recorded and analyzed. The mean age of the surgical patients at the time of stress fracture was 22.6 years. The mean duration of preoperative symptoms before surgical intervention was 25.8 months. Four of the dancers were male and 3 were female. All had failed nonoperative treatment regimens. Five patients (5 tibias) underwent drilling and bone grafting of the lesion, and 2 patients (3 tibias) with completed fractures or multiple refractory stress fractures underwent intramedullary nailing. Clinical union was achieved at a mean of 6 weeks and radiographic union at 5.1 months. Return to full dance activity was at an average of 6.5 months postoperatively. Surgical intervention for tibial stress fractures in dancers who have not responded to nonoperative management allowed for resolution of symptoms and return to dancing with minimal morbidity.

  16. kISMET: Stress and fracture characterization in a deep mine

    NASA Astrophysics Data System (ADS)

    Oldenburg, C. M.; Dobson, P. F.; Daley, T. M.; Birkholzer, J. T.; Cook, P. J.; Ajo Franklin, J. B.; Rutqvist, J.; Siler, D.; Kneafsey, T. J.; Nakagawa, S.; Wu, Y.; Guglielmi, Y.; Ulrich, C.; Marchesini, P.; Wang, H. F.; Haimson, B. C.; Sone, H.; Vigilante, P.; Roggenthen, W.; Doe, T.; Lee, M.; Mattson, E.; Huang, H.; Johnson, T. C.; Morris, J.; White, J. A.; Johnson, P. A.; Coblentz, D. D.; Heise, J.

    2016-12-01

    We are developing a community facility called kISMET (permeability (k) and Induced Seismicity Management for Energy Technologies) at the Sanford Underground Research Facility (SURF) in Lead, SD. The purpose of kISMET is to investigate stress and the effects of rock fabric on hydraulic fracturing. Although findings from kISMET may have broad applications that inform stress and fracturing in anisotropic rock, results will be most applicable to improving control of hydraulic fracturing for enhanced geothermal systems (EGS) in crystalline rock. At the kISMET site on the 4850 ft (1480 m depth) level of SURF, we have drilled and cored an array of nearly vertical boreholes in Precambrian phyllite. The array consists of four 50-m deep monitoring boreholes surrounding one 100-m deep borehole forming a 6 m-wide five-spot pattern at a depth of 1530 m. Previous investigations of the stress field at SURF suggest that the principal stress s1 is nearly vertical. By aligning the kISMET boreholes approximately with σ1, fractures created in the center borehole should in theory be perpendicular to σ3, the least principal horizontal stress. But the phyllite at kISMET has a strong fabric (foliation) that could influence fracturing. Stress measurements and stimulation using hydraulic fracturing will be carried out in the center borehole using a straddle packer and high-pressure pump. We will use an impression packer and image logs after stress testing and stimulation to determine fracture orientation and extent at the center borehole. In order to study the control of stress, rock fabric, and stimulation approach on size, aperture, and orientation of hydraulic fractures, we will carefully monitor the stress measurements and stimulation. For example, we will use continuous active source seismic (CASSM) in two of the monitoring boreholes to measure changes in seismic-wave velocity as water fills the fracture. Second, near real-time electrical resistance tomography (ERT) will be used in

  17. Anterior tibial stress fractures treated with anterior tension band plating in high-performance athletes.

    PubMed

    Cruz, Alexandre Santa; de Hollanda, João Paris Buarque; Duarte, Aires; Hungria Neto, José Soares

    2013-06-01

    The non-surgical treatment of anterior tibial cortex stress fractures requires long periods of abstention from sports activities and often results in non-union. Many different surgical techniques have already been previously described to treat these fractures, but there is no consensus on the best treatment. We describe the outcome of treatment using anterior tibial tension band plating in three high-performance athletes (4 legs) with anterior tibial cortex stress fractures. Tibial osteosynthesis with a 3.5-mm locking compression plate in the anterolateral aspect of the tibia was performed in all patients diagnosed with anterior tibial stress fracture after September 2010 at Santa Casa Hospital. All of the fractures were consolidated within a period of 3 months after surgery, allowing for an early return to pre-injury levels of competitive sports activity. There were no infection, non-union, malunion or anterior knee pain complications. Anterior tibial tension band plating leads to prompt fracture consolidation and is a good alternative for the treatment of anterior tibial cortex stress fractures. Bone grafts were shown to be unnecessary.

  18. Elastic stress transmission and transformation (ESTT) by confined liquid: A new mechanics for fracture in elastic lithosphere of the earth

    Xu, Xing-Wang; Peters, Stephen; Liang, Guang-He; Zhang, Bao-Lin

    2016-01-01

    Tectonic stress alters local stress fields in the surrounding country rocks and therefore synchronously varies the local effective tensile tangential stress and the nature and geometry of the liquid-driven fractures.

  19. Stress fractures of the ribs and upper extremities: causation, evaluation, and management.

    PubMed

    Miller, Timothy L; Harris, Joshua D; Kaeding, Christopher C

    2013-08-01

    Stress fractures are common troublesome injuries in athletes and non-athletes. Historically, stress fractures have been thought to predominate in the lower extremities secondary to the repetitive stresses of impact loading. Stress injuries of the ribs and upper extremities are much less common and often unrecognized. Consequently, these injuries are often omitted from the differential diagnosis of rib or upper extremity pain. Given the infrequency of this diagnosis, few case reports or case series have reported on their precipitating activities and common locations. Appropriate evaluation for these injuries requires a thorough history and physical examination. Radiographs may be negative early, requiring bone scintigraphy or MRI to confirm the diagnosis. Nonoperative and operative treatment recommendations are made based on location, injury classification, and causative activity. An understanding of the most common locations of upper extremity stress fractures and their associated causative activities is essential for prompt diagnosis and optimal treatment.

  20. In situ stress and fracture permeability along the Stillwater fault zone, Dixie Valley Nevada

    Hickman, S.H.; Barton, C.A.; Zoback, M.D.; Morin, R.; Sass, J.; Benoit, R.

    1997-01-01

    Borehole televiewer and hydrologic logging and hydraulic fracturing stress measurements were carried out in a 2.7-km-deep geothermal production well (73B-7) drilled into the Stillwater fault zone. Precision temperature and spinner flowmeter logs were also acquired in well 73B-7, with and without simultaneously injecting water into the well. Localized perturbations to well-bore temperature and flow were used to identify hydraulically conductive fractures. Comparison of these data with fracture orientations from the televiewer log indicates that permeable fractures within and adjacent to the Stillwater fault zone are critically stressed, potentially active shear planes in the current west-northwest extensional stress regime at Dixie Valley.

  1. Marrow changes in anorexia nervosa masking the presence of stress fractures on MR imaging.

    PubMed

    Tins, Bernhard; Cassar-Pullicino, Victor

    2006-11-01

    Patients with anorexia nervosa (AN) usually have abnormal bone and bone marrow metabolism resulting in osteopenia and serous bone marrow change. There is an increased risk of stress/insufficiency fractures and these can be the first presentation of AN. This case report describes a patient with previously undiagnosed AN who presented with foot pain. The serous bone marrow changes of AN were found to mask the MR imaging features of stress fractures, as both had low T1w and high T2w and STIR signal intensities. Contrast enhancement was not helpful but actually masked fractures. Scintigraphy was helpful. The radiologist might be the first clinician to raise the possibility of AN and should be aware of the difficulties in diagnosing stress fractures in bones with underlying serous bone marrow change. In this severe case of AN even the heel fat pad and the fat pad in Kager's triangle had undergone serous change.

  2. First-rib stress fracture in two adolescent swimmers: a case report.

    PubMed

    Low, Sara; Kern, Michael; Atanda, Alfred

    2016-01-01

    First-rib stress fractures have been described in adolescent athletes in various sports, with only one prior case report of first-rib stress fractures in an adolescent female swimmer. There is a need for research on the cause, management, and prevention of these injuries as they lead to significant morbidity and critical time away from sport for these aspiring athletes. We aimed to describe first-rib stress fractures as a potential cause for non-specific atraumatic chronic shoulder pain in adolescent swimmers and to discuss the different presentations, unique risk factors, treatment, and potential injury prevention strategies of such fractures. We discussed two such cases which were successfully treated with activity modification with restriction of all overhead activity, gradually progressive physical therapy and a return to swimming protocol. First-rib stress fractures can vary in presentation and should be in the differential diagnosis in adolescent swimmers with chronic shoulder pain. These injuries can be successfully managed with rest from overhead activities and physical therapy. Gradual return to competitive swimming can be achieved even with non-union of a first-rib stress fracture. Emphasis on balanced strength training in different muscle groups and proper swimming technique is essential to prevent these injuries.

  3. Stress dependence of permeability of intact and fractured shale cores.

    NASA Astrophysics Data System (ADS)

    van Noort, Reinier; Yarushina, Viktoriya

    2016-04-01

    Whether a shale acts as a caprock, source rock, or reservoir, understanding fluid flow through shale is of major importance for understanding fluid flow in geological systems. Because of the low permeability of shale, flow is thought to be largely confined to fractures and similar features. In fracking operations, fractures are induced specifically to allow for hydrocarbon exploration. We have constructed an experimental setup to measure core permeabilities, using constant flow or a transient pulse. In this setup, we have measured the permeability of intact and fractured shale core samples, using either water or supercritical CO2 as the transporting fluid. Our measurements show decreasing permeability with increasing confining pressure, mainly due to time-dependent creep. Furthermore, our measurements show that for a simple splitting fracture, time-dependent creep will also eliminate any significant effect of this fracture on permeability. This effect of confinement on fracture permeability can have important implications regarding the effects of fracturing on shale permeability, and hence for operations depending on that.

  4. The cumulative effect of bisphosphonates and statins on stress fractures. Is it a failure of steroid biosynthesis? Case Report.

    PubMed

    Dzugan, Sergey S; Dzugan, Sergey A

    2016-01-01

    Osteoporosis related fractures pose a significant economic and healthcare problem. There is a growing concern about increased numbers of stress or low energy fractures after bisphosphonates therapy. A 65-year-old woman is presented with a stress fracture of the left femur. From our point of view, this fracture was associated with a long-term statin and bisphosphonate therapy. We did not find a similar presentation in medical literature.

  5. Stress fracture and premenstrual syndrome in Japanese adolescent athletes: a cross-sectional study.

    PubMed

    Takeda, Takashi; Imoto, Yoko; Nagasawa, Hiroyo; Takeshita, Atsuko; Shiina, Masami

    2016-10-18

    To investigate the relationship between the occurrence of stress fracture and premenstrual syndrome (PMS)/premenstrual dysphoric disorder (PMDD) in Japanese adolescent athletes. Cross-sectional study. Osaka, Japan. A school-based survey on menstruation and school life was conducted using a sample of 1818 Japanese female students who belonged to two public high schools in Japan. Among them, we recruited 394 athletes who had regular menstrual cycles (25-38 days) and completed a questionnaire about their premenstrual symptoms and their competitive career. Premenstrual symptoms and the occurrence of stress fracture. The prevalences of moderate-to-severe PMS and PMDD were 8.9% and 1.3%, respectively, which were the same as in collegiate athletes in a previous study. Premenstrual symptoms disturbed 'Work efficiency or productivity, home responsibilities', 'Relationships with coworkers or family' and 'Athletic performance in training or competition' more severely than menstrual pain (p=0.031, p=0.004 and p<0.001, respectively). 66 athletes (16.8%) reported having experienced a stress fracture. The severity of 'Overeating or food cravings', 'Physical symptoms' and 'Performance in training or competition' in athletes with previous stress fractures were much higher than in those without a history of stress fractures (p=0.015, p=0.008 and p=0.006, respectively). In terms of premenstrual symptoms, 'Physical symptoms' was associated with an increased risk of stress fractures in athletes (OR 1.66, 95% CI 1.06 to 2.62). The results from this study indicated that premenstrual symptoms may affect athletic performance and has the risk of stress fractures in adolescent athletes. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  6. Case report: multifocal subchondral stress fractures of the femoral heads and tibial condyles in a young military recruit.

    PubMed

    Yoon, Pil Whan; Yoo, Jeong Joon; Yoon, Kang Sup; Kim, Hee Joong

    2012-03-01

    Subchondral stress fractures of the femoral head may be either of the insufficiency-type with poor quality bone or the fatigue-type with normal quality bone but subject to high repetitive stresses. Unlike osteonecrosis, multiple site involvement rarely has been reported for subchondral stress fractures. We describe a case of multifocal subchondral stress fractures involving femoral heads and medial tibial condyles bilaterally within 2 weeks. A 27-year-old military recruit began having left knee pain after 2 weeks of basic training, without any injury. Subsequently, right knee, right hip, and left hip pain developed sequentially within 2 weeks. The diagnosis of multifocal subchondral stress fracture was confirmed by plain radiographs and MR images. Nonoperative treatment of the subchondral stress fractures of both medial tibial condyles and the left uncollapsed femoral head resulted in resolution of symptoms. The collapsed right femoral head was treated with a fibular strut allograft to restore congruity and healed without further collapse. There has been one case report in which an insufficiency-type subchondral stress fracture of the femoral head and medial femoral condyle occurred within a 2-year interval. Because the incidence of bilateral subchondral stress fractures of the femoral head is low and multifocal involvement has not been reported, multifocal subchondral stress fractures can be confused with multifocal osteonecrosis. Our case shows that subchondral stress fractures can occur in multiple sites almost simultaneously.

  7. Hydraulic fracturing stress measurement in underground salt rock mines at Upper Kama Deposit

    NASA Astrophysics Data System (ADS)

    Rubtsova, EV; Skulkin, AA

    2018-03-01

    The paper reports the experimental results on hydraulic fracturing in-situ stress measurements in potash mines of Uralkali. The selected HF procedure, as well as locations and designs of measuring points are substantiated. From the evidence of 78 HF stress measurement tests at eight measuring points, it has been found that the in-situ stress field is nonequicomponent, with the vertical stresses having value close to the estimates obtained with respect to the overlying rock weight while the horizontal stresses exceed the gravity stresses by 2–3 times.

  8. Information on stress conditions in the oceanic crust from oval fractures in a deep borehole

    Morin, R.H.

    1990-01-01

    Oval images etched into the wall of a deep borehole were detected in DSDP Hole 504B, eastern equatorial Pacific Ocean, from analysis of an acoustic televiewer log. A systematic inspection of these ovals has identified intriguing consistencies in appearance that cannot be explained satisfactorily by a random, coincidental distribution of pillow lavas. As an alternative hypothesis, Mohr-Coulomb failure criterion is used to account for the generation and orientation of similarly curved, stress-induced fractures. Consequently, these oval features can be interpreted as fractures and related directly to stress conditions in the oceanic crust at this site. The azimuth of the oval center corresponds to the orientation of maximum horizontal principal stress (SH), and the oval width, which spans approximately 180?? of the borehole, is aligned with the azimuth of minimum horizontal principal stress (Sh). The oval height is controlled by the fracture angle and thus is a function of the coefficient of internal friction of the rock. -from Author

  9. Dynamic Stress Testing Is Unnecessary for Unimalleolar Supination-External Rotation Ankle Fractures with Minimal Fracture Displacement on Lateral Radiographs.

    PubMed

    Nortunen, Simo; Leskelä, Hannu-Ville; Haapasalo, Heidi; Flinkkilä, Tapio; Ohtonen, Pasi; Pakarinen, Harri

    2017-03-15

    This study aimed to identify factors from standard radiographs that contributed to the stability of the ankle mortise in patients with isolated supination-external rotation fractures of the lateral malleolus (OTA/AO 44-B). Non-stress radiographs of the mortise and lateral views, without medial clear space widening or incongruity, were prospectively collected for 286 consecutive patients (mean age, 45 years [range, 16 to 85 years]), including 144 female patients (mean age, 50 years [range, 17 to 85 years]) and 142 male patients (mean age, 40 years [range, 16 to 84 years]) from 2 trauma centers. The radiographs were analyzed for fracture morphology by 2 orthopaedic surgeons, who were blinded to each other's measurements and to the results of external rotation stress radiographs (the reference for stability). Factors significantly associated with ankle mortise stability were tested in multiple logistic regression. Receiver operating characteristic analyses were performed for continuous variables to determine optimal thresholds. A sensitivity of >90% was used as the criterion for an optimal threshold. According to external rotation stress radiographs, 217 patients (75.9%) had a stable injury, defined as that with a medial clear space of <5 mm. Independent factors that predicted stable ankle mortise were female sex (odds ratio [OR], 2.5 [95% confidence interval (CI), 1.4 to 4.6]), a posterior diastasis of <2 mm (corresponding with a sensitivity of 0.94 and specificity of 0.39) on lateral radiographs (OR, 10.8 [95% CI, 3.7 to 31.5]), and only 2 fracture fragments (OR, 7.3 [95% CI, 2.1 to 26.3]). When the posterior diastasis was <2 mm and only 2 fracture fragments were present, the probability of a stable ankle mortise was 0.98 for 48 female patients (16.8%) and 0.94 for 37 male patients (12.9%). Patients with noncomminuted lateral malleolar fractures (85 patients [29.7%]) could be diagnosed with a stable ankle mortise without further stress testing, when the fracture

  10. The association of novel polymorphisms with stress fracture injury in Elite Athletes: Further insights from the SFEA cohort.

    PubMed

    Varley, Ian; Hughes, David C; Greeves, Julie P; Stellingwerff, Trent; Ranson, Craig; Fraser, William D; Sale, Craig

    2018-06-01

    To determine, in conjunction with a wider investigation, whether 11 genetic variants in the vicinity of vitamin D, collagen and Wnt signalling pathways were associated with stress fracture injury in the Stress Fracture Elite Athlete (SFEA) cohort. Genotype-phenotype association study. Self-reported stress fracture history and demographic data were recorded in 518 elite athletes, 449 male and 69 female (mean age 24.2±5.5 years) from the SFEA cohort. Elite athletes were assigned to two groups based on history of stress fracture injury. Data were analysed for the whole cohort and sub-stratified in to male only and multiple stress fracture cases. Genotype was determined using a proprietary fluorescence-based competitive allele-specific polymerase chain reaction assay. SOST SNP rs1877632 and VDR SNPs rs10735810 and rs731236 were associated with stress fracture (p<0.05). In the whole cohort, rs1877632 heterozygotes and homozygotes of the rare allele combined made up 59% of stress fracture sufferers in comparison to 46% in the non-stress fracture group (p=0.05). In the multiple stress fracture cohort, homozygotes of the rare allele of rs10735810 and rs731236 showed an association with stress fracture when compared to those homozygotes for the common allele combined with heterozygotes (p=0.03; p=0.01). No significant associations were shown in the other SNPs analysed (p>0.05). These data suggest an important role for SOST SNP rs1877632 and VDR SNPs rs10735810 and rs731236 in the pathophysiology of stress fracture. This might be due to the role of the SNPs in the regulation of bone remodelling and adaptation to mechanical loading, with potential implications for the prevention and treatment of stress fracture injuries. Copyright © 2017. Published by Elsevier Ltd.

  11. Preventive osteopathic manipulative treatment and stress fracture incidence among collegiate cross-country athletes.

    PubMed

    Brumm, Lynn F; Janiski, Carrie; Balawender, Jenifer L; Feinstein, Adam

    2013-12-01

    Stress fractures are common among athletes, particularly distance runners, with many theories regarding the etiologic process of stress fractures and various studies identifying risk factors or suggesting preventive techniques. To our knowledge, no previous studies have discussed the possible causative effects of somatic dysfunction or the preventive capabilities of osteopathic manipulative treatment (OMT). To apply a preventive OMT protocol for cross-country athletes to reduce the incidence of stress fractures. Cohort study. Examinations of cross-country athletes at an NCAA (National Collegiate Athletic Association) Division I university were performed by supervising physician-examiners and first- and second-year osteopathic medical students during several consecutive academic years. Athletes re-enrolled in the study each year they continued to be eligible. The intervention included osteopathic structural examination and OMT that focused on somatic dysfunction identified in the pelvis, sacrum, and lower extremities. More than 1800 participant examinations were performed on 124 male and female participants by 3 supervising physician-examiners and 141 osteopathic medical students over the course of 5 consecutive academic years (2004-2005 to 2008-2009). Data from these academic years were compared with data from the previous 8 academic years (1996-1997 to 2003-2004). An average of 20 new participants enrolled yearly. The number of annual stress fractures per team ranged from 0 to 6 for male participants and 1 to 6 for female participants. The cumulative annual incidence of stress fractures for male participants demonstrated a statistically significant decrease from 13.9% (20 of 144) before intervention to 1.0% (1 of 105) after intervention, resulting in a 98.7% relative reduction in stress-fracture diagnosis (P=.019). The cumulative annual incidence for female participants showed a minimal decrease from 12.9% (23 of 178) before intervention to 12.0% (17 of 142) after

  12. Acute changes in foot strike pattern and cadence affect running parameters associated with tibial stress fractures.

    PubMed

    Yong, Jennifer R; Silder, Amy; Montgomery, Kate L; Fredericson, Michael; Delp, Scott L

    2018-05-18

    Tibial stress fractures are a common and debilitating injury that occur in distance runners. Runners may be able to decrease tibial stress fracture risk by adopting a running pattern that reduces biomechanical parameters associated with a history of tibial stress fracture. The purpose of this study was to test the hypothesis that converting to a forefoot striking pattern or increasing cadence without focusing on changing foot strike type would reduce injury risk parameters in recreational runners. Running kinematics, ground reaction forces and tibial accelerations were recorded from seventeen healthy, habitual rearfoot striking runners while running in their natural running pattern and after two acute retraining conditions: (1) converting to forefoot striking without focusing on cadence and (2) increasing cadence without focusing on foot strike. We found that converting to forefoot striking decreased two risk factors for tibial stress fracture: average and peak loading rates. Increasing cadence decreased one risk factor: peak hip adduction angle. Our results demonstrate that acute adaptation to forefoot striking reduces different injury risk parameters than acute adaptation to increased cadence and suggest that both modifications may reduce the risk of tibial stress fractures. Copyright © 2018 Elsevier Ltd. All rights reserved.

  13. Hydraulic fracture orientation and production/injection induced reservoir stress changes in diatomite waterfloods

    SciT

    Wright, C.A.; Conant, R.A.; Golich, G.M.

    1995-12-31

    This paper summarizes the (preliminary) findings from extensive field studies of hydraulic fracture orientation in diatomite waterfloods and related efforts to monitor the induced surface subsidence. Included are case studies from the Belridge and Lost Hills diatomite reservoirs. The primary purpose of the paper is to document a large volume of tiltmeter hydraulic fracture orientation data that demonstrates waterflood-induced fracture reorientation--a phenomenon not previously considered in waterflood development planning. Also included is a brief overview of three possible mechanisms for the observed waterflood fracture reorientation. A discussion section details efforts to isolate the operative mechanism(s) from the most extensive casemore » study, as well as suggesting a possible strategy for detecting and possibly mitigating some of the adverse effects of production/injection induced reservoir stress changes--reservoir compaction and surface subsidence as well as fracture reorientation.« less

  14. Effect of Stress Triaxiality on the Flow and Fracture of Mg Alloy AZ31

    NASA Astrophysics Data System (ADS)

    Kondori, Babak; Benzerga, A. Amine

    2014-07-01

    The microscopic damage mechanisms operating in a hot-rolled magnesium alloy AZ31B are investigated under both uniaxial and controlled triaxial loadings. Their connection to macroscopic fracture strains and fracture mode (normal vs shear) is elucidated using postmortem fractography, interrupted tests, and microscopic analysis. The fracture locus (strain-to-failure vs stress triaxiality) exhibits a maximum at moderate triaxiality, and the strain-to-failure is found to be greater in notched specimens than in initially smooth ones. A transition from twinning-induced fracture under uniaxial loading to microvoid coalescence fracture under triaxial loading is evidenced. It is argued that this transition accounts in part for the observed greater ductility in notched bars. The evolution of plastic anisotropy with stress triaxiality is also investigated. It is inferred that anisotropic plasticity at a macroscopic scale suffices to account for the observed transition in the fracture mode from flat (triaxial loading) to shear-like (uniaxial loading). Damage is found to initiate at second-phase particles and deformation twins. Fracture surfaces of broken specimens exhibit granular morphology, coarse splits, twin-sized crack traces, as well as shallow and deep dimples, in proportions that depend on the overall stress triaxiality and fracture mode. An important finding is that AZ31B has a greater tolerance to ductile damage accumulation than has been believed thus far, based on the fracture behavior in uniaxial specimens. Another finding, common to both tension and compression, is the increase in volumetric strain, the microscopic origins of which remain to be elucidated.

  15. Effect of Crack Tip Stress Concentration Factor on Fracture Resistance in Vacuum Environment

    DTIC Science & Technology

    2015-01-20

    indicate: (1) in all alloys, the fracture resistance is highest for blunt-notches (smaller Kt), and is lowest for fatigue -sharpened precracked...paths are transgranular and the fracture mode is ductile void coalescence in all cases, irrespective of the stress concentration factor. 20-01-2015...because of corrosion and/or various loading conditions such as fatigue , fretting, abrasion, etc. Also, the geometry of the structure may cause an

  16. Crack-jump mechanism of microvein formation and its implications for stress cyclicity during extension fracturing

    NASA Astrophysics Data System (ADS)

    Caputo, Riccardo; Hancock, Paul L.

    1998-11-01

    It is well accepted and documented that faulting is produced by the cyclic behaviour of a stress field. Some extension fractures, such as veins characterised by the crack-seal mechanism, have also been presumed to result from repeated stress cycles. In the present note, some commonly observed field phenomena and relationships such as hackle marks and vein and joint spacing, are employed to argue that a stress field can also display cyclic behaviour during extensional fracturing. Indeed, the requirement of critical stress conditions for the occurrence of extensional failure events does not accord with the presence of contemporaneously open nearby parallel fractures. Therefore, because after each fracture event there is stress release within the surrounding volume of rock, high density sets of parallel extensional fractures also strongly support the idea that rocks undergo stress cyclicity during jointing and veining. A comparison with seismological data from earthquakes with dipole mechanical solutions, confirms that this process presently occurs at depth in the Earth crust. Furthermore, in order to explain dense sets of hair-like closely spaced microveins, a crack-jump mechanism is introduced here as an alternative to the crack-seal mechanism. We also propose that as a consequence of medium-scale stress cyclicity during brittle deformation, the re-fracturing of a rock mass occurs in either one or the other of these two possible ways depending on the ratio between the elastic parameters of the sealing material and those of the host rock. The crack-jump mechanism occurs when the former is stronger.

  17. Greater Polar Moment of Inertia at the Tibia in Athletes Who Develop Stress Fractures

    PubMed Central

    Weidauer, Lee A.; Binkley, Teresa; Vukovich, Matt; Specker, Bonny

    2014-01-01

    Background: Several previous investigations have determined potential risk factors for stress fractures in athletes and military personnel. Purpose: To determine factors associated with the development of stress fractures in female athletes. Study Design: Case-control study; Level of evidence, 3. Methods: A total of 88 female athletes (cross-country, n = 29; soccer, n = 15; swimming, n = 9; track and field, n = 14; volleyball, n = 12; and basketball, n = 9) aged 18 to 24 years were recruited to participate in a longitudinal bone study and had their left distal tibia at the 4%, 20%, and 66% sites scanned by peripheral quantitative computed tomography (pQCT). Patients included 23 athletes who developed stress fractures during the following year (cases). Whole body, hip, and spine scans were obtained using dual-energy x-ray absorptiometry (DXA). Analysis of covariance was used to determine differences in bone parameters between cases and controls after adjusting for height, lower leg length, lean mass, fat mass, and sport. Results: No differences were observed between cases and controls in any of the DXA measurements. Cases had significantly greater unadjusted trabecular bone mineral content (BMC), greater polar moment of inertia (PMI) at the 20% site, and greater cortical BMC at the 66% site; however, after adjusting for covariates, the differences became nonsignificant. When analyses were repeated using all individuals who had ever had a stress fracture as cases (n = 31) and after controlling for covariates, periosteal circumference was greater in the cases than the controls (71.1 ± 0.7 vs 69.4 ± 0.5 mm, respectively; P = .04). Conclusion: A history of stress fractures is associated with larger bones. These findings are important because larger bones were previously reported to be protective against fractures and stress fractures, but study findings indicate that may not always be true. One explanation could be that individuals who sustain stress fractures have

  18. Results of the multiwell experiment in situ stresses, natural fractures, and other geological controls on reservoirs

    NASA Astrophysics Data System (ADS)

    Lorenz, John C.; Warpinski, Norman R.; Teufel, Lawrence W.; Branagan, Paul T.; Sattler, Allan R.; Northrop, David A.

    Hundreds of millions of cubic meters of natural gas are locked up in low-permeability, natural gas reservoirs. The Multiwell Experiment (MWX) was designed to characterize such reservoirs, typical of much of the western United States, and to assess and develop a technology for the production of this unconventional resource. Flow-rate tests of the MWX reservoirs indicate a system permeability that is several orders of magnitude higher than laboratory permeability measurements made on matrix-rock sandstones. This enhanced permeability is caused by natural fractures. The single set of fractures present in the reservoirs provides a significant permeability anisotropy that is aligned with the maximum in situ horizontal stress. Hydraulic fractures therefore form parallel to the natural fractures and are consequently an inefficient mechanism for stimulation. Successful stimulation may be possible by perturbing the local stress field with a large hydraulic fracture in one well so that a second hydraulic fracture in an offset well propagates transverse to the natural fracture permeability trend.

  19. Stress-induced, time-dependent fracture closure at hydrothermal conditions

    Beeler, N.M.; Hickman, S.H.

    2004-01-01

    Time-dependent closure of fractures in quartz was measured in situ at 22-530??C temperature and 0.1-150 MPa water pressure. Unlike previous crack healing and rock permeability studies, in this study, fracture aperture is monitored directly and continuously using a windowed pressure vessel, a long-working-distance microscope, and reflected-light interferometry. Thus the fracture volume and geometry can be measured as a function of time, temperature, and water pressure. Relatively uniform closure occurs rapidly at temperatures and pressures where quartz becomes significantly soluble in water. During closure the aperture is reduced by as much as 80% in a few hours. We infer that this closure results from the dissolution of small particles or asperities that prop the fracture open. The driving force for closure via dissolution of the prop is the sum of three chemical potential terms: (1) the dissolution potential, proportional to the logarithm of the degree of undersaturation of the solution; (2) the coarsening potential, proportional to the radius of curvature of the prop; and (3) the pressure solution potential, proportional to the effective normal stress at the contact between propping particles and the fracture wall. Our observations suggest that closure is controlled by a pressure solution-like process. The aperture of dilatant fractures and microcracks in the Earth that are similar to those in our experiments, such as ones generated from thermal stressing or brittle failure during earthquake rupture and slip, will decrease rapidly with time, especially if the macroscopic stress is nonhydrostatic.

  20. Stress fractures of the ribs in elite competitive rowers: a report of nine cases.

    PubMed

    Dragoni, S; Giombini, A; Di Cesare, A; Ripani, M; Magliani, G

    2007-10-01

    The objective was to report the clinical and imaging patterns of nine cases of stress fractures of the rib diagnosed in Italian Olympic rowers. Nine patients with stress fractures of the rib detected from 103 (8.7%) Italian team rowers competing between May 2000 and May 2006 were identified based on the database of a sports medicine institute. All athletes were male. They were aged between 17 and 31 years (mean: 24.4). Patient weight, fracture location, rowing side and imaging methods employed were noted. The diagnosis was made based on history, clinical examination and Tc-99m MDP bone scintigraphy. Eight of the 9 fractures were located anterolaterally between the fourth and ninth rib. In 1 of the 5 athletes with standard radiographs, a fracture line was visible and in 4 there was callus formation. In 2 athletes sonography was performed, which detected discontinuity of the rib surface and callus formation (1 case each). Stress fractures of the ribs are relatively common in competitive rowers. They are characterized by increasing lateral chest pain and typical scintigraphic, radiographic and sonographic findings.

  1. 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.

  2. Rockfall triggering by cyclic thermal stressing of exfoliation fractures

    Collins, Brian D.; Stock, Greg M.

    2016-01-01

    Exfoliation of rock deteriorates cliffs through the formation and subsequent opening of fractures, which in turn can lead to potentially hazardous rockfalls. Although a number of mechanisms are known to trigger rockfalls, many rockfalls occur during periods when likely triggers such as precipitation, seismic activity and freezing conditions are absent. It has been suggested that these enigmatic rockfalls may occur due to solar heating of rock surfaces, which can cause outward expansion. Here we use data from 3.5 years of field monitoring of an exfoliating granite cliff in Yosemite National Park in California, USA, to assess the magnitude and temporal pattern of thermally induced rock deformation. From a thermodynamic analysis, we find that daily, seasonal and annual temperature variations are sufficient to drive cyclic and cumulative opening of fractures. Application of fracture theory suggests that these changes can lead to further fracture propagation and the consequent detachment of rock. Our data indicate that the warmest times of the day and year are particularly conducive to triggering rockfalls, and that cyclic thermal forcing may enhance the efficacy of other, more typical rockfall triggers.

  3. Fatigue Stress Fracture of the Talar Body: An Uncommon Cause of Ankle Pain.

    PubMed

    Kim, Young Sung; Lee, Ho Min; Kim, Jong Pil; Moon, Han Sol

    2016-01-01

    Fatigue stress fractures of the talus are rare and usually involve the head of the talus in military recruits. We report an uncommon cause of ankle pain due to a fatigue stress fracture of the body of the talus in a 32-year-old male social soccer player. Healing was achieved after weightbearing suppression for 6 weeks. Although rare, a stress fracture of the body of the talus should be considered in an athlete with a gradual onset of chronic ankle pain. Magnetic resonance imaging and bone scan are useful tools for early diagnosis. Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  4. Bilateral stress fracture of the fibulae and periostitis of the tibiae.

    PubMed

    Tsuchie, Hiroyuki; Okada, Kyoji; Nagasawa, Hiroyuki; Chida, Shuichi; Shimada, Yoichi

    2010-01-01

    This study describes a unique case of bilateral stress fractures of the fibulae and provides a literature review. A 16-year-old female badminton player presented with pain around the bilateral distal lateral legs. She had mild bilateral varus deformity at the knee joint, and the bilateral ankles showed valgus deformity in standing posture. Radiographs and computed tomography showed periosteal reactions on the bilateral distal fibulae. Technetium-99m bone scintigraphy demonstrated increased uptake in the bilateral distal fibulae and the bilateral middle third of the tibiae. A diagnosis of bilateral distal fibular stress fractures was made. She was advised to stop playing badminton until the symptoms disappeared. Varus deformity of the knee and valgus deformity of the ankle may have influenced the mechanism underlying bilateral symmetric stress fractures. Copyright © 2010 S. Karger AG, Basel.

  5. Regional flow simulation in fractured aquifers using stress-dependent parameters.

    PubMed

    Preisig, Giona; Joel Cornaton, Fabien; Perrochet, Pierre

    2012-01-01

    A model function relating effective stress to fracture permeability is developed from Hooke's law, implemented in the tensorial form of Darcy's law, and used to evaluate discharge rates and pressure distributions at regional scales. The model takes into account elastic and statistical fracture parameters, and is able to simulate real stress-dependent permeabilities from laboratory to field studies. This modeling approach gains in phenomenology in comparison to the classical ones because the permeability tensors may vary in both strength and principal directions according to effective stresses. Moreover this method allows evaluation of the fracture porosity changes, which are then translated into consolidation of the medium. © 2011, The Author(s). Ground Water © 2011, National Ground Water Association.

  6. Effective-stress-law behavior of Austin chalk rocks for deformation and fracture conductivity

    SciT

    Warpinski, N.R.; Teufel, L.W.

    Austin chalk core has been tested to determine the effective law for deformation of the matrix material and the stress-sensitive conductivity of the natural fractures. For deformation behavior, two samples provided data on the variations of the poroelastic parameter, {alpha}, for Austin chalk, giving values around 0.4. The effective-stress-law behavior of a Saratoga limestone sample was also measured for the purpose of obtaining a comparison with a somewhat more porous carbonate rock. {alpha} for this rock was found to be near 0.9. The low {alpha} for the Austin chalk suggests that stresses in the reservoir, or around the wellbore, willmore » not change much with changes in pore pressure, as the contribution of the fluid pressure is small. Three natural fractures from the Austin chalk were tested, but two of the fractures were very tight and probably do not contribute much to production. The third sample was highly conductive and showed some stress sensitivity with a factor of three reduction in conductivity over a net stress increase of 3000 psi. Natural fractures also showed a propensity for permanent damage when net stressed exceeded about 3000 psi. This damage was irreversible and significantly affected conductivity. {alpha} was difficult to determine and most tests were inconclusive, although the results from one sample suggested that {alpha} was near unity.« less

  7. Fractured rock stress-permeability relationships from in situ data and effects of temperature and chemical-mechanical couplings

    SciT

    Rutqvist, J.

    The purpose of this paper is to (i) review field data on stress-induced permeability changes in fractured rock; (ii) describe estimation of fractured rock stress-permeability relationships through model calibration against such field data; and (iii) discuss observations of temperature and chemically mediated fracture closure and its effect on fractured rock permeability. The field data that are reviewed include in situ block experiments, excavation-induced changes in permeability around tunnels, borehole injection experiments, depth (and stress) dependent permeability, and permeability changes associated with a large-scale rock-mass heating experiment. Data show how the stress-permeability relationship of fractured rock very much depends on localmore » in situ conditions, such as fracture shear offset and fracture infilling by mineral precipitation. Field and laboratory experiments involving temperature have shown significant temperature-driven fracture closure even under constant stress. Such temperature-driven fracture closure has been described as thermal overclosure and relates to better fitting of opposing fracture surfaces at high temperatures, or is attributed to chemically mediated fracture closure related to pressure solution (and compaction) of stressed fracture surface asperities. Back-calculated stress-permeability relationships from field data may implicitly account for such effects, but the relative contribution of purely thermal-mechanical and chemically mediated changes is difficult to isolate. Therefore, it is concluded that further laboratory and in situ experiments are needed to increase the knowledge of the true mechanisms behind thermally driven fracture closure, and to further assess the importance of chemical-mechanical coupling for the long-term evolution of fractured rock permeability.« less

  8. Fractured rock stress-permeability relationships from in situ data and effects of temperature and chemical-mechanical couplings

    DOE PAGES

    Rutqvist, J.

    2014-09-19

    The purpose of this paper is to (i) review field data on stress-induced permeability changes in fractured rock; (ii) describe estimation of fractured rock stress-permeability relationships through model calibration against such field data; and (iii) discuss observations of temperature and chemically mediated fracture closure and its effect on fractured rock permeability. The field data that are reviewed include in situ block experiments, excavation-induced changes in permeability around tunnels, borehole injection experiments, depth (and stress) dependent permeability, and permeability changes associated with a large-scale rock-mass heating experiment. Data show how the stress-permeability relationship of fractured rock very much depends on localmore » in situ conditions, such as fracture shear offset and fracture infilling by mineral precipitation. Field and laboratory experiments involving temperature have shown significant temperature-driven fracture closure even under constant stress. Such temperature-driven fracture closure has been described as thermal overclosure and relates to better fitting of opposing fracture surfaces at high temperatures, or is attributed to chemically mediated fracture closure related to pressure solution (and compaction) of stressed fracture surface asperities. Back-calculated stress-permeability relationships from field data may implicitly account for such effects, but the relative contribution of purely thermal-mechanical and chemically mediated changes is difficult to isolate. Therefore, it is concluded that further laboratory and in situ experiments are needed to increase the knowledge of the true mechanisms behind thermally driven fracture closure, and to further assess the importance of chemical-mechanical coupling for the long-term evolution of fractured rock permeability.« less

  9. The incidence and distribution of stress fractures in elite tennis players

    PubMed Central

    Maquirriain, J; Ghisi, J P

    2006-01-01

    Background Modern professional tennis involves powerful movements repeatedly subjecting the musculoskeletal system to heavy mechanical load. Thus tennis players are exposed to high risk of overuse injuries including stress fractures. Objective To determine the incidence and distribution of stress fractures in elite tennis players. Study design Retrospective cohort study. Methods The cohort study population consisted of 139 elite players (mean (SD) age, 20.0 (5.0) years; 48 female, 91 male). Stress fractures were identified and confirmed radiologically from medical records during a two year period. Injuries were analysed according to age, sex, site, severity, delay in diagnosis, and time needed to return to sports. Results 15 players sustained 18 stress fractures, corresponding to an overall case incidence of 12.9% (95% confidence interval (CI), 8.1 to 20.0). The tarsal navicular was most affected (n = 5; 27%), followed by the pars interarticularis (n = 3; 16%), the metatarsals (n = 3; 16%), the tibia (n = 2; 11%) and the lunate (n = 2; 11%). Magnetic resonance imaging showed a greater incidence of “high grade” lesions (94.4%). Stress fracture incidence was significantly higher in juniors (20.3% (95% CI, 11.4 to 33.2)) than in professional players (7.5% (2.8 to 15.6)) (p = 0.045). Conclusions There was a high absolute risk (12.9%) of stress fractures in elite tennis players over a two year period. Junior players were at highest risk. The lesions are a major cause of disruption both of training and of competition. Risk factors should therefore be identified and prevention emphasised. PMID:16632579

  10. Predicting Fluid Flow in Stressed Fractures: A Quantitative Evaluation of Methods

    NASA Astrophysics Data System (ADS)

    Weihmann, S. A.; Healy, D.

    2015-12-01

    Reliable estimation of fracture stability in the subsurface is crucial to the success of exploration and production in the petroleum industry, and also for wider applications to earthquake mechanics, hydrogeology and waste disposal. Previous work suggests that fracture stability is related to fluid flow in crystalline basement rocks through shear or tensile instabilities of fractures. Our preliminary scoping analysis compares the fracture stability of 60 partly open (apertures 1.5-3 cm) and electrically conductive (low acoustic amplitudes relative to matrix) fractures from a 16 m section of a producing zone in a basement well in Bayoot field, Yemen, to a non-producing zone in the same well (also 16 m). We determine the Critically Stressed Fractures (CSF; Barton et al., 1995) and dilatation tendency (Td; Ferrill et al., 1999). We find that: 1. CSF (Fig. 1) is a poor predictor of high fluid flow in the inflow zone; 88% of the fractures are predicted to be NOT critically stressed and yet they all occur within a zone of high fluid flow rate 2. Td (Fig. 2) is also a poor predictor of high fluid flow in the inflow zone; 67% of the fractures have a LOW Td(< 0.6) 3. For the non-producing zone CSF is a very reliable predictor (100% are not critically stressed) whereas the values of Tdare consistent with their location in non-producing interval (81% are < 0.6) (Fig. 3 & 4). In summary, neither method correlates well with the observed abundance of hydraulically conductive fractures within the producing zone. Within the non-producing zone CSF and Td make reasonably accurate predictions. Fractures may be filled or partially filled with drilling mud or a lower density and electrically conductive fill such as clay in the producing zone and therefore appear (partly) open. In situ stress, fluid pressure, rock properties (friction, strength) and fracture orientation data used as inputs for the CSF and Td calculations are all subject to uncertainty. Our results suggest that scope

  11. PATIENT-SPECIFIC FINITE ELEMENT ANALYSIS OF CHRONIC CONTACT STRESS EXPOSURE AFTER INTRA-ARTICULAR FRACTURE OF THE TIBIAL PLAFOND

    PubMed Central

    Li, Wendy; Anderson, Donald D.; Goldsworthy, Jane K.; Marsh, J. Lawrence; Brown, Thomas D.

    2008-01-01

    SUMMARY The role of altered contact mechanics in the pathogenesis of post-traumatic osteoarthritis (PTOA) following intra-articular fracture remains poorly understood. One proposed etiology is that residual incongruities lead to altered joint contact stresses that, over time, predispose to PTOA. Prevailing joint contact stresses following surgical fracture reduction were quantified in this study using patient-specific contact finite element (FE) analysis. FE models were created for 11 ankle pairs from tibial plafond fracture patients. Both (reduced) fractured ankles and their intact contralaterals were modeled. A sequence of 13 loading instances was used to simulate the stance phase of gait. Contact stresses were summed across loadings in the simulation, weighted by resident time in the gait cycle. This chronic exposure measure, a metric of degeneration propensity, was then compared between intact and fractured ankle pairs. Intact ankles had lower peak contact stress exposures that were more uniform, and centrally located. The series-average peak contact stress elevation for fractured ankles was 38% (p=0.0015; peak elevation was 82%). Fractured ankles had less area with low contact stress exposure than intacts, and a greater area with high exposure. Chronic contact stress overexposures (stresses exceeding a damage threshold) ranged from near zero to a high of 18 times the matched intact value. The patient-specific FE models utilized in this study represent substantial progress towards elucidating the relationship between altered contact stresses and the outcome of patients treated for intra-articular fractures. PMID:18404662

  12. 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.

  13. An integrated workflow for stress and flow modelling using outcrop-derived discrete fracture networks

    NASA Astrophysics Data System (ADS)

    Bisdom, K.; Nick, H. M.; Bertotti, G.

    2017-06-01

    Fluid flow in naturally fractured reservoirs is often controlled by subseismic-scale fracture networks. Although the fracture network can be partly sampled in the direct vicinity of wells, the inter-well scale network is poorly constrained in fractured reservoir models. Outcrop analogues can provide data for populating domains of the reservoir model where no direct measurements are available. However, extracting relevant statistics from large outcrops representative of inter-well scale fracture networks remains challenging. Recent advances in outcrop imaging provide high-resolution datasets that can cover areas of several hundred by several hundred meters, i.e. the domain between adjacent wells, but even then, data from the high-resolution models is often upscaled to reservoir flow grids, resulting in loss of accuracy. We present a workflow that uses photorealistic georeferenced outcrop models to construct geomechanical and fluid flow models containing thousands of discrete fractures covering sufficiently large areas, that does not require upscaling to model permeability. This workflow seamlessly integrates geomechanical Finite Element models with flow models that take into account stress-sensitive fracture permeability and matrix flow to determine the full permeability tensor. The applicability of this workflow is illustrated using an outcropping carbonate pavement in the Potiguar basin in Brazil, from which 1082 fractures are digitised. The permeability tensor for a range of matrix permeabilities shows that conventional upscaling to effective grid properties leads to potential underestimation of the true permeability and the orientation of principal permeabilities. The presented workflow yields the full permeability tensor model of discrete fracture networks with stress-induced apertures, instead of relying on effective properties as most conventional flow models do.

  14. The impact of different aperture distribution models and critical stress criteria on equivalent permeability in fractured rocks

    NASA Astrophysics Data System (ADS)

    Bisdom, Kevin; Bertotti, Giovanni; Nick, Hamidreza M.

    2016-05-01

    Predicting equivalent permeability in fractured reservoirs requires an understanding of the fracture network geometry and apertures. There are different methods for defining aperture, based on outcrop observations (power law scaling), fundamental mechanics (sublinear length-aperture scaling), and experiments (Barton-Bandis conductive shearing). Each method predicts heterogeneous apertures, even along single fractures (i.e., intrafracture variations), but most fractured reservoir models imply constant apertures for single fractures. We compare the relative differences in aperture and permeability predicted by three aperture methods, where permeability is modeled in explicit fracture networks with coupled fracture-matrix flow. Aperture varies along single fractures, and geomechanical relations are used to identify which fractures are critically stressed. The aperture models are applied to real-world large-scale fracture networks. (Sub)linear length scaling predicts the largest average aperture and equivalent permeability. Barton-Bandis aperture is smaller, predicting on average a sixfold increase compared to matrix permeability. Application of critical stress criteria results in a decrease in the fraction of open fractures. For the applied stress conditions, Coulomb predicts that 50% of the network is critically stressed, compared to 80% for Barton-Bandis peak shear. The impact of the fracture network on equivalent permeability depends on the matrix hydraulic properties, as in a low-permeable matrix, intrafracture connectivity, i.e., the opening along a single fracture, controls equivalent permeability, whereas for a more permeable matrix, absolute apertures have a larger impact. Quantification of fracture flow regimes using only the ratio of fracture versus matrix permeability is insufficient, as these regimes also depend on aperture variations within fractures.

  15. Predictors of Stress Fracture Susceptibility in Young Female Recruits

    DTIC Science & Technology

    2004-09-02

    fracture as women who ran 4 or more times a week (OR = 2.17; 95% CI, 1.0-4.5). Among measures of reproductive history and birth control pill use, only...the analyses on menstrual function. No significant associations were found for birth control pill use. After adjusting for age and other potential...and Odds Ratios by Measures of Self-Reported Reproductive History, and Birth Control Use, Female Marine Corps Recruits, Parris Island, March 1995 to

  16. Excess Stress Fractures, Musculoskeletal Injuries, and Health Care Utilization Among Unfit and Overweight Female Army Trainees.

    PubMed

    Krauss, Margot R; Garvin, Nadia U; Boivin, Michael R; Cowan, David N

    2017-02-01

    Musculoskeletal injuries are prevalent among military trainees and certain occupations. Fitness and body mass index (BMI) have been associated with musculoskeletal conditions, including stress fractures. The incidence of, and excess health care utilization for, stress fracture and non-stress fracture overuse musculoskeletal injuries during the first 6 months of service is higher among unfit female recruits. Those who exceeded body fat limits are at a greater risk of incident stress fractures, injuries, or health care utilization compared with weight-qualified recruits. Cohort study; Level of evidence, 3. All applicants to the United States Army were required to take a preaccession fitness test during the study period (February 2005-September 2006). The test included a 5-minute step test scored as pass or fail. BMI was recorded at application. There were 2 distinct comparisons made in this study: (1) between weight-qualified physically fit and unfit women and (2) between weight-qualified physically fit women and those who exceeded body fat limits. We compared the incidence of, and excess health care utilization for, musculoskeletal injuries, including stress fractures and physical therapy visits, during the first 183 days of military service. Among the weight-qualified women, unfit participants had a higher non-stress fracture injury incidence and related excess health care utilization rate compared with fit women, with rate ratios of 1.32 (95% CI, 1.14-1.53) and 1.18 (95% CI, 1.10-1.27), respectively. Among fit women, compared with the weight-qualified participants, those exceeding body fat limits had higher rate ratios for non-stress fracture injury incidence and related excess health care utilization of 1.27 (95% CI, 1.07-1.50) and 1.20 (95% CI, 1.11-1.31), respectively. Weight-qualified women who were unfit had a higher incidence of stress fractures and related excess health care utilization compared with fit women, with rate ratios of 1.62 (95% CI, 1

  17. HYDRAULIC FRACTURING IN PORUS AND NONPORUS ROCK AND ITS POTENTIAL FOR DETERMINING IN-SITU STRESSES AT GREAT DEPTH.

    DTIC Science & Technology

    The process of Hydraulic Fracturing as a method of determining in-situ stresses in brittle elastic formations at great depth is analyzed both...theoretically and experimentally. Theoretically, it is found that in attempting to relate the recorded hydraulic fracturing pressures to tectonic stresses...at great depth. The experimental results show that hydraulic fracturing occurred when the internal pressure achieved a critical value that could

  18. Pore Pressure and Stress Distributions Around a Hydraulic Fracture in Heterogeneous Rock

    NASA Astrophysics Data System (ADS)

    Gao, Qian; Ghassemi, Ahmad

    2017-12-01

    One of the most significant characteristics of unconventional petroleum bearing formations is their heterogeneity, which affects the stress distribution, hydraulic fracture propagation and also fluid flow. This study focuses on the stress and pore pressure redistributions during hydraulic stimulation in a heterogeneous poroelastic rock. Lognormal random distributions of Young's modulus and permeability are generated to simulate the heterogeneous distributions of material properties. A 3D fully coupled poroelastic model based on the finite element method is presented utilizing a displacement-pressure formulation. In order to verify the model, numerical results are compared with analytical solutions showing excellent agreements. The effects of heterogeneities on stress and pore pressure distributions around a penny-shaped fracture in poroelastic rock are then analyzed. Results indicate that the stress and pore pressure distributions are more complex in a heterogeneous reservoir than in a homogeneous one. The spatial extent of stress reorientation during hydraulic stimulations is a function of time and is continuously changing due to the diffusion of pore pressure in the heterogeneous system. In contrast to the stress distributions in homogeneous media, irregular distributions of stresses and pore pressure are observed. Due to the change of material properties, shear stresses and nonuniform deformations are generated. The induced shear stresses in heterogeneous rock cause the initial horizontal principal stresses to rotate out of horizontal planes.

  19. Macro-mesoscopic Fracture and Strength Character of Pre-cracked Granite Under Stress Relaxation Condition

    NASA Astrophysics Data System (ADS)

    Liu, Junfeng; Yang, Haiqing; Xiao, Yang; Zhou, Xiaoping

    2018-05-01

    The fracture characters are important index to study the strength and deformation behavior of rock mass in rock engineering. In order to investigate the influencing mechanism of loading conditions on the strength and macro-mesoscopic fracture character of rock material, pre-cracked granite specimens are prepared to conduct a series of uniaxial compression experiments. For parts of the experiments, stress relaxation tests of different durations are also conducted during the uniaxial loading process. Furthermore, the stereomicroscope is adopted to observe the microstructure of the crack surfaces of the specimens. The experimental results indicate that the crack surfaces show several typical fracture characters in accordance with loading conditions. In detail, some cleavage fracture can be observed under conventional uniaxial compression and the fractured surface is relatively rough, whereas as stress relaxation tests are attached, relative slip trace appears between the crack faces and some shear fracture starts to come into being. Besides, the crack faces tend to become smoother and typical terrace structures can be observed in local areas. Combining the macroscopic failure pattern of the specimens, it can be deduced that the duration time for the stress relaxation test contributes to the improvement of the elastic-plastic strain range as well as the axial peak strength for the studied material. Moreover, the derived conclusion is also consistent with the experimental and analytical solution for the pre-peak stage of the rock material. The present work may provide some primary understanding about the strength character and fracture mechanism of hard rock under different engineering environments.

  20. Effects of Stretch Shortening Cycle Exercise Fatigue on Stress Fracture Injury Risk during Landing

    ERIC Educational Resources Information Center

    James, C. Roger; Dufek, Janet S.; Bates, Barry T.

    2006-01-01

    The purpose of this study was to examine changes in landing performance during fatigue that could result in increased stress fracture injury risk. Five participants performed nonfatigued and fatigued drop landings (0.60 m), while ground reaction force (GRF), electromyographic (EMG) activity, and kinematics were recorded. Fatigue was defined as a…

  1. [A boy with a painful knee: bone tumour or stress fracture?].

    PubMed

    Robben, Bart J; Jutte, Paul C

    2012-01-01

    The symptoms of a stress fracture are almost identical to those of most bone tumours. Even with the use of various imaging techniques, it can be difficult to establish the correct diagnosis. Although a primary bone tumour requires early treatment to improve its prognosis, the discriminative factor in the diagnosis of a stress fracture is its clinical development over time. A 10-year-old boy was referred to our outpatient clinic on the suspicion of a primary bone tumour in his right tibia. A case was once described in this journal in which a stress fracture had eventually led to an amputation. The suspicion of primary bone tumour often marks the start of a long and intense diagnostic course. A stress fracture is the major diagnostic pitfall when there is a suspicion of such a tumour. If doubts persist after a diagnostic work-up by imaging, consultation with the Bone Tumour Committee is indicated. The patient can also be quickly referred to a centre specialised in treating bone tumours, as was the case in this article.

  2. [Stress fractures in disabled athletes' preparation for the paralympic games in Athens, 2004: an assessment].

    PubMed

    Laboute, E; Druvert, J C; Pailler, D; Piera, J-B

    2008-03-01

    To identify stress fracture frequency and the associated risk factors in disabled female athletes preparing the Paralympic Games in Athens in 2004. The study is focused on four athletes (including one with a vision impairment) among the 31 women selected to participate in the Paralympic Games. The medical records of selected athletes not having been able to participate in the Games due to a stress fracture were analyzed. One case of stress fracture to the first metatarsal was reported of one below-knee amputee and an additional case to the second metatarsal of one hemiplegic athlete. Two of three athletes with physical disability were unable to participate in the Games because of stress fracture occurring during the preparatory phase. Among four athletes selected to take part in the Paralympic Games. If morphological predispositions are inherent to the sportswomen, the main favouring factor to be retained is their running asymmetry. Training programmes must therefore take this characteristic into account and must not offer heavy-load repetitive exercise (such as endurance or jogging) at the expense of technique. Over-intense training exposes the disabled athlete to this type of pathology and is likely to affect his chances of competing.

  3. Determining the minimum in situ stress from hydraulic fracturing through perforations

    SciT

    Warpinski, N.R.

    Hydraulic fracture stress measurements have been performed through perforations at depths from 1310 to 2470 m at the US Department of Energy's Multiwell Experiment site. The results of over sixty stress tests conducted through perforations have shown that small-volume hydraulic fractures generally provide an accurate, reproducible measurement of the minimum in situ stress. However, unusual behavior can occur in some tests and techniques to evaluate the behavior are suggested. Unclear instantaneous shut-in pressures, which are found on occasional tests, are difficult to evaluate, but the problem appears to be a complex stress state; reprocessing the data using log-log or othermore » functions does not necessarily provide the correct stress value. The possible error in such tests should be assessed from the original pressure-time data and not the reprocessing techniques. Stress results show that the stress distribution is dependent on lithology at this site; mudstones, shales and other nonreservoir rocks generally have a near-lithostatic stress, while sandstones have a considerably lower minimum stress value. 30 refs., 18 figs., 4 tabs.« less

  4. Association of stressful life events with incident falls and fractures in older men: the Osteoporotic Fractures in Men (MrOS) Study

    PubMed Central

    Fink, Howard A.; Kuskowski, Michael A.; Marshall, Lynn M.

    2014-01-01

    Background: small, retrospective studies suggest that major life events and/or sudden emotional stress may increase fall and fracture risk. The current study examines these associations prospectively. Methods: a total of 5,152 men aged ≥65 years in the Osteoporotic Fractures in Men study self-reported data on stressful life events for 1 year prior to study Visit 2. Incident falls and fractures were ascertained for 1 year after Visit 2. Fractures were centrally confirmed. Results: a total of 2,932 (56.9%) men reported ≥1 type of stressful life event. In men with complete stressful life event, fall and covariate data (n = 3,949), any stressful life event was associated with a 33% increased risk of incident fall [relative risk (RR) 1.33, 95% confidence interval (CI) 1.19–1.49] and 68% increased risk of multiple falls (RR = 1.68, 95% CI = 1.40–2.01) in the year following Visit 2 after adjustment for age, education, Parkinson's disease, diabetes, stroke, instrumental activities of daily living (IADL) impairment, chair stand time, walk speed, multiple past falls, depressive symptoms and antidepressant use. Risk increased with the number of types of stressful life events. Though any stressful life event was associated with a 58% increased age-adjusted risk for incident fracture, this association was attenuated and no longer statistically significant after additional adjustment for total hip bone mineral density, fracture after age 50, Parkinson's disease, stroke and IADL impairment. Conclusions: in this cohort of older men, stressful life events significantly increased risk of incident falls independent of other explanatory variables, but did not independently increase incident fracture risk. PMID:24002237

  5. Use of non-fault fractures in stress tensor reconstruction using the Mohr Circle with the Win-tensor program

    NASA Astrophysics Data System (ADS)

    Delvaux, Damien

    2016-04-01

    Paleostress inversion of geological fault-slip data is usually done using the directional part of the applied stress tensor on a slip plane and comparing it with the observed slip lines. However, this method do not fully exploit the brittle data sets as those are composed of shear and tension fractures, in addition to faults. Brittle deformation can be decomposed in two steps. An initial fracture/failure in previously intact rock generate extension/tensile fractures or shear fractures, both without visible opening or displacement. This first step may or not be followed by fracture opening to form tension joints, frictional shearing to form shear faults, or a combination of opening and shearing which produces hybrid fractures. Fractured rock outcrop contain information of the stress conditions that acted during both brittle deformation steps. The purpose here is to investigate how the fracture pattern generated during the initial fracture/failure step might be used in paleostress reconstruction. Each fracture is represented on the Mohr Circle by its resolved normal and shear stress magnitudes. We consider the typical domains on the Mohr circle where the different types de fractures nucleate (tension, hybrid, shear and compression fractures), as well the domain which contain reactivated fractures (faults reactivating an initial fracture plane). In function of the fracture type defined in the field, a "distance" is computed on the Mohr circle between each point and its expected corresponding nucleation/reactivation domain. This "Mohr Distance" is then used as function to minimize during the inversion. We implemented this new function in the Win-Tensor program, and tested it with natural and synthetic data sets from different stress regimes. It can be used alone using only the Mohr Distance on each plane (function F10), or combined with the angular misfit between observed striae and resolved shear directions (composite function F11). When used alone (F10), only the 3

  6. 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.

  7. 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.

  8. Dependency of the injection induced seismicity b-value on the stress state of existing fractures

    NASA Astrophysics Data System (ADS)

    Mukuhira, Y.; Fehler, M. C.; Ito, T.; Asanuma, H.; Häring, M. O.

    2017-12-01

    The Gutenberg-Richter distribution of earthquake is a power law relationship and it holds for laboratory scale earthquakes (acoustic emission) to subduction zone earthquakes as well as induced seismicity. The gradient of the power law is known as the b-value, which can be considered the ratio of the number of the larger earthquakes to small ones. Larger earthquakes are often observed in low b-value regions, or alternatively a b-value reduction has been observed before some main shocks. Some authors have argued that b-value is negatively correlated with differential stress level. Therefore, a b-value anomaly found in time-space analysis may be used for detection of an area of stress concentration and used for earthquake prediction or hazard risk assessment. In the field of induced seismicity where b-value reduction has also been observed, the physical mechanism of b-value reduction has not been understood well. Since induced seismicity related with fluid injection usually occurs at depths around 1000 5000 m, a significant tectonic mechanism to cause a stress concentration during a short time of hydraulic stimulation might not be expected. We used borehole analysis and focal mechanism information to investigate the stress state on the existing fractures that caused induced seismicity. Then we divide the catalog into the groups with varying normalized shear stress threshold and estimated the b-value. We found that b-value for the events that occurred along higher shear stress fractures were significantly lower (figure 1a) than those from the moderate/lower shear stress fractures (figure 1b). Thus, b-value dependency on the shear stress can be observed for induced seismicity on a reservoir scale. Therefore, we propose that the reason for the observed b-value reductions in induced seismicity on a reservoir scale is the events that occur along higher shear stress fractures. Supposing that the earthquakes occurs along well-orientated fractures, the b-value dependence on

  9. Fractures

    MedlinePlus

    A fracture is a break, usually in a bone. If the broken bone punctures the skin, it is called an open ... falls, or sports injuries. Other causes are low bone density and osteoporosis, which cause weakening of the ...

  10. Are Elite Female Soccer Athletes at Risk for Disordered Eating Attitudes, Menstrual Dysfunction, and Stress Fractures?

    PubMed

    Prather, Heidi; Hunt, Devyani; McKeon, Kathryn; Simpson, Scott; Meyer, E Blair; Yemm, Ted; Brophy, Robert

    2016-03-01

    To determine the prevalence of stress fractures, menstrual dysfunction and disordered eating attitudes in elite female soccer athletes. Cross-sectional descriptive study. Female soccer athletes were recruited from a national level youth soccer club, an NCAA Division I university team, and a women's professional team. Two hundred twenty female soccer athletes with a mean age of 16.4 ± 4 years and BMI of 20.8 ± 2 kg/m(2) completed the study, representing all athletes from the included teams. One-time surveys completed by the athletes. Height and weight were recorded, and body mass index (BMI) was calculated for each athlete. Athletes reported age of menarche, history of missing 3 or more menses within a 12-month period and stress fracture. The Eating Attitudes Test (EAT-26) was used to assess the athlete's body perception and attitudes toward eating. Of the 220 soccer athletes, 3 athletes (1.6%) had a low BMI for their age, and 19 (8.6%) reported stress fractures of the lower extremity. Among athletes who had reached menarche, the average onset was 13 + 1 year; menstrual dysfunction were present in 21 (19.3%). On the EAT-26, 1 player scored in the high risk range (>20) and 17 (7.7%) scored in the intermediate risk range (10-19) for eating disorders. Athletes with an EAT-26 score ≥ 10 points had a significantly higher prevalence of menstrual dysfunction in the past year compared to athletes with an EAT-26 score of less than 10 (P = .02). Elite female soccer athletes are susceptible to stress fractures and menstrual dysfunction and have delayed onset of menarche despite normal BMI and appropriate body perception and attitudes towards eating. Further studies are needed to better understand stress fracture risk in female soccer athletes and in other team sports to determine how these findings relate to long-term bone health in this population. Copyright © 2016. Published by Elsevier Inc.

  11. Intrapartum sacral stress fracture due to pregnancy-related osteoporosis: a case report.

    PubMed

    Oztürk, Gülcan; Külcü, Duygu Geler; Aydoğ, Ece

    2013-01-01

    Low back pain (LBP) and hip pain frequently occur during pregnancy and postpartum period. Although pelvic and mechanic lesions of the soft tissues are most responsible for the etiology, sacral fracture is also one of the rare causes. A 32-year-old primigravid patient presented with LBP and right hip pain which started 3 days after vaginal delivery. Although direct radiographic examination was normal, magnetic resonance imaging of the sacrum revealed sacral stress fracture. Lumbar spine and femoral bone mineral density showed osteoporosis as a risk factor. There were no other risk factors such as trauma, excessive weight gain, and strenuous physical activity. It is considered that the patient had sacral fatigue and insufficiency fracture in intrapartum period. The patient's symptoms subsided in 3 months after physical therapy and rest. In conclusion, sacral fractures during pregnancy and postpartum period, especially resulting from childbirth, are very rare. To date, there are two cases in the literature. In cases who even do not have risk factors related to vaginal delivery such as high birth weight infant and the use of forceps, exc., sacral fracture should be considered in the differential diagnosis of LBP and hip pain started soon after child birth. Pregnancy-related osteoporosis may lead to fracture during vaginal delivery.

  12. Stress-induced, time-dependent fracture closure at hydrothermal conditions

    NASA Astrophysics Data System (ADS)

    Beeler, N. M.; Hickman, S. H.

    2004-02-01

    Time-dependent closure of fractures in quartz was measured in situ at 22-530°C temperature and 0.1-150 MPa water pressure. Unlike previous crack healing and rock permeability studies, in this study, fracture aperture is monitored directly and continuously using a windowed pressure vessel, a long-working-distance microscope, and reflected-light interferometry. Thus the fracture volume and geometry can be measured as a function of time, temperature, and water pressure. Relatively uniform closure occurs rapidly at temperatures and pressures where quartz becomes significantly soluble in water. During closure the aperture is reduced by as much as 80% in a few hours. We infer that this closure results from the dissolution of small particles or asperities that prop the fracture open. The driving force for closure via dissolution of the prop is the sum of three chemical potential terms: (1) the dissolution potential, proportional to the logarithm of the degree of undersaturation of the solution; (2) the coarsening potential, proportional to the radius of curvature of the prop; and (3) the pressure solution potential, proportional to the effective normal stress at the contact between propping particles and the fracture wall. Our observations suggest that closure is controlled by a pressure solution-like process. The aperture of dilatant fractures and microcracks in the Earth that are similar to those in our experiments, such as ones generated from thermal stressing or brittle failure during earthquake rupture and slip, will decrease rapidly with time, especially if the macroscopic stress is nonhydrostatic.

  13. Estimation of In Situ Stresses with Hydro-Fracturing Tests and a Statistical Method

    NASA Astrophysics Data System (ADS)

    Lee, Hikweon; Ong, See Hong

    2018-03-01

    At great depths, where borehole-based field stress measurements such as hydraulic fracturing are challenging due to difficult downhole conditions or prohibitive costs, in situ stresses can be indirectly estimated using wellbore failures such as borehole breakouts and/or drilling-induced tensile failures detected by an image log. As part of such efforts, a statistical method has been developed in which borehole breakouts detected on an image log are used for this purpose (Song et al. in Proceedings on the 7th international symposium on in situ rock stress, 2016; Song and Chang in J Geophys Res Solid Earth 122:4033-4052, 2017). The method employs a grid-searching algorithm in which the least and maximum horizontal principal stresses ( S h and S H) are varied, and the corresponding simulated depth-related breakout width distribution as a function of the breakout angle ( θ B = 90° - half of breakout width) is compared to that observed along the borehole to determine a set of S h and S H having the lowest misfit between them. An important advantage of the method is that S h and S H can be estimated simultaneously in vertical wells. To validate the statistical approach, the method is applied to a vertical hole where a set of field hydraulic fracturing tests have been carried out. The stress estimations using the proposed method were found to be in good agreement with the results interpreted from the hydraulic fracturing test measurements.

  14. Epidemiology of stress fracture injuries among US high school athletes, 2005-2006 through 2012-2013.

    PubMed

    Changstrom, Bradley G; Brou, Lina; Khodaee, Morteza; Braund, Cortney; Comstock, R Dawn

    2015-01-01

    High school athletes in the United States sustain millions of injuries annually, approximately 10% of which are fractures. However, there is no clear estimate of the number of stress fractures sustained by high school athletes annually despite reports that stress fractures account for 0.7% to 20% of injuries seen in sports medicine clinics. This suggests a high utilization of resources for a potentially preventable injury. In addition, stress fractures have been associated with low energy availability and disordered eating in young athletes, highlighting the importance of early recognition and intervention. To investigate stress fracture rates and patterns in a large national sample of US high school athletes. Descriptive epidemiologic study. Data from High School RIO (Reporting Information Online), a national sports injury surveillance study, were analyzed to describe rates and patterns of stress fracture injury sustained from 2005-2006 through 2012-2013, across sports and by sex. From 2005-2006 through 2012-2013, a total of 51,773 injuries were sustained during 25,268,873 athlete-exposures, of which 389 (0.8%) were stress fractures, resulting in an overall stress fracture rate of 1.54 per 100,000 athlete-exposures. Rates per 100,000 athlete-exposures were highest in girls' cross country (10.62), girls' gymnastics (7.43), and boys' cross country (5.42). In sex-comparable sports, girls sustained more stress fractures (63.3%) than did boys (36.7%) and had higher rates of stress fracture (2.22 vs 1.27; rate ratio, 1.75; 95% CI, 1.38-2.23). The most commonly injured sites were the lower leg (40.3% of all stress fractures), foot (34.9%), and lower back/lumbar spine/pelvis (15.2%). Management was nonsurgical in 98.7% of the cases, and 65.3% of injuries resulted in ≥3 weeks of time loss, medical disqualification, or an end to the season before athletes could return to play. Although a rare injury, stress fractures cause considerable morbidity for high school athletes

  15. A Comparison between Deep and Shallow Stress Fields in Korea Using Earthquake Focal Mechanism Inversions and Hydraulic Fracturing Stress Measurements

    NASA Astrophysics Data System (ADS)

    Lee, Rayeon; Chang, Chandong; Hong, Tae-kyung; Lee, Junhyung; Bae, Seong-Ho; Park, Eui-Seob; Park, Chan

    2016-04-01

    We are characterizing stress fields in Korea using two types of stress data: earthquake focal mechanism inversions (FMF) and hydraulic fracturing stress measurements (HF). The earthquake focal mechanism inversion data represent stress conditions at 2-20 km depths, whereas the hydraulic fracturing stress measurements, mostly conducted for geotechnical purposes, have been carried out at depths shallower than 1 km. We classified individual stress data based on the World Stress Map quality ranking scheme. A total of 20 FMF data were classified into A-B quality, possibly representing tectonic stress fields. A total of 83 HF data out of compiled 226 data were classified into B-C quality, which we use for shallow stress field characterization. The tectonic stress, revealed from the FMF data, is characterized by a remarkable consistency in its maximum stress (σ1) directions in and around Korea (N79±2° E), indicating a quite uniform deep stress field throughout. On the other hand, the shallow stress field, represented by HF data, exhibits local variations in σ1 directions, possibly due to effects of topography and geologic structures such as faults. Nonetheless, there is a general similarity in σ1 directions between deep and shallow stress fields. To investigate the shallow stress field statistically, we follow 'the mean orientation and wavelength analysis' suggested by Reiter et al. (2014). After the stress pattern analysis, the resulting stress points distribute sporadically over the country, not covering the entire region evenly. In the western part of Korea, the shallow σ1directions are generally uniform with their search radius reaching 100 km, where the average stress direction agrees well with those of the deep tectonic stress. We note two noticeable differences between shallow and deep stresses in the eastern part of Korea. First, the shallow σ1 orientations are markedly non-uniform in the southeastern part of Korea with their search radius less than 25 km

  16. Tension Band Plating for Chronic Anterior Tibial Stress Fractures in High-Performance Athletes.

    PubMed

    Zbeda, Robert M; Sculco, Peter K; Urch, Ekaterina Y; Lazaro, Lionel E; Borens, Olivier; Williams, Riley J; Lorich, Dean G; Wellman, David S; Helfet, David L

    2015-07-01

    Anterior tibial stress fractures are associated with high rates of delayed union and nonunion, which can be particularly devastating to a professional athlete who requires rapid return to competition. Current surgical treatment strategies include intramedullary nailing, which has satisfactory rates of fracture union but an associated risk of anterior knee pain. Anterior tension band plating is a biomechanically sound alternative treatment for these fractures. Tension band plating of chronic anterior tibial stress fractures leads to rapid healing and return to physical activity and avoids the anterior knee pain associated with intramedullary nailing. Case series; Level of evidence, 4. Between 2001 and 2013, there were 13 chronic anterior tibial stress fractures in 12 professional or collegiate athletes who underwent tension band plating after failing nonoperative management. Patient charts were retrospectively reviewed for demographics, injury history, and surgical details. Radiographs were used to assess time to osseous union. Follow-up notes and phone interviews were used to determine follow-up time, return to training time, and whether the patient was able to return to competition. Cases included 13 stress fractures in 12 patients (9 females, 3 males). Five patients were track-and-field athletes, 4 patients played basketball, 2 patients played volleyball, and 1 was a ballet dancer. Five patients were Division I collegiate athletes and 7 were professional or Olympic athletes. Average age at time of surgery was 23.6 years (range, 20-32 years). Osseous union occurred on average at 9.6 weeks (range, 5.3-16.9 weeks) after surgery. Patients returned to training on average at 11.1 weeks (range, 5.7-20 weeks). Ninety-two percent (12/13) eventually returned to preinjury competition levels. Thirty-eight percent (5/13) underwent removal of hardware for plate prominence. There was no incidence of infection or nonunion. Anterior tension band plating for chronic tibial stress

  17. Proximal tibia stress fracture with Osteoarthritis of knee − Radiological and functional analysis of one stage TKA with long stem

    PubMed Central

    Soundarrajan, Dhanasekaran; Rajkumar, Natesan; Dhanasekararaja, Palanisamy; Rajasekaran, Shanmuganathan

    2018-01-01

    Introduction: Proximal tibia stress fractures with knee osteoarthritis pose a challenging situation. We evaluated the radiological and functional outcome of one-stage total knee arthroplasty (TKA) and long stem for patients with varied grades of knee arthritis and proximal tibia stress fractures.  Methods: We analysed 20 patients from April 2012 to March 2017 with proximal tibia stress fractures associated with knee osteoarthritis of varied grades. Out of 20 patients, five were acute fresh fractures. The mean age was 64 years (range, 52–78) which includes three men and 17 women. Previous surgery in the same limb, rheumatoid arthritis, valgus deformity were excluded. All patients were treated with posterior stabilised TKA with long stem, of which, four patients had screw augmentation for medial tibial bone defect and two patients with malunited fracture at stress fracture site required osteotomy, plating and bone grafting. Two patients had two level stress fracture of tibia in the same leg. Results: The mean follow-up period was 28 (range, 6–60) months. The mean tibiofemoral angle improved from 18.27° varus to 1.8° valgus. The mean knee society score improved from 21.9 (range, −10 to 45) to 82.8 (range, 15–99) [p < 0.05]. The mean Knee Society functional score improved from 15.5 (range, −10 to 40) to 76.8 (range, 10–100) [p < 0.05]. All fractures got united at the last follow-up. One patient had infection and wound dehiscence at six months for which debridement done and had poor functional outcome. Conclusion: TKA with long stem gives excellent outcome, irrespective of severity of arthritis associated with stress fracture. By restoring limb alignment and bypassing the fracture site, it facilitates fracture healing. Early detection and prompt intervention is necessary to prevent the progression to recalcitrant non-union or malunion. PMID:29667926

  18. Proximal tibia stress fracture with Osteoarthritis of knee - Radiological and functional analysis of one stage TKA with long stem.

    PubMed

    Soundarrajan, Dhanasekaran; Rajkumar, Natesan; Dhanasekararaja, Palanisamy; Rajasekaran, Shanmuganathan

    2018-01-01

    Proximal tibia stress fractures with knee osteoarthritis pose a challenging situation. We evaluated the radiological and functional outcome of one-stage total knee arthroplasty (TKA) and long stem for patients with varied grades of knee arthritis and proximal tibia stress fractures.  Methods: We analysed 20 patients from April 2012 to March 2017 with proximal tibia stress fractures associated with knee osteoarthritis of varied grades. Out of 20 patients, five were acute fresh fractures. The mean age was 64 years (range, 52-78) which includes three men and 17 women. Previous surgery in the same limb, rheumatoid arthritis, valgus deformity were excluded. All patients were treated with posterior stabilised TKA with long stem, of which, four patients had screw augmentation for medial tibial bone defect and two patients with malunited fracture at stress fracture site required osteotomy, plating and bone grafting. Two patients had two level stress fracture of tibia in the same leg. The mean follow-up period was 28 (range, 6-60) months. The mean tibiofemoral angle improved from 18.27° varus to 1.8° valgus. The mean knee society score improved from 21.9 (range, -10 to 45) to 82.8 (range, 15-99) [p < 0.05]. The mean Knee Society functional score improved from 15.5 (range, -10 to 40) to 76.8 (range, 10-100) [p < 0.05]. All fractures got united at the last follow-up. One patient had infection and wound dehiscence at six months for which debridement done and had poor functional outcome. TKA with long stem gives excellent outcome, irrespective of severity of arthritis associated with stress fracture. By restoring limb alignment and bypassing the fracture site, it facilitates fracture healing. Early detection and prompt intervention is necessary to prevent the progression to recalcitrant non-union or malunion. © The Authors, published by EDP Sciences, 2018.

  19. Comparison of stress fractures of male and female recruits during basic training in the Israeli anti-aircraft forces.

    PubMed

    Gam, Arnon; Goldstein, Liav; Karmon, Yuval; Mintser, Igor; Grotto, Itamar; Guri, Alex; Goldberg, Avishay; Ohana, Nissim; Onn, Erez; Levi, Yehezkel; Bar-Dayan, Yaron

    2005-08-01

    In military basic training, stress fractures are a common orthopedic problem. Female recruits have a significantly higher incidence of stress fractures than do male recruits. Because the Israeli Defense Forces opened traditionally male roles in combat units to female recruits, their high risk for stress fractures is of concern. To compare the prevalence of stress fractures during Israeli Defense Forces anti-aircraft basic training among otherwise healthy young male and female recruits, in terms of anatomic distribution and severity. Ten mixed gender batteries, including 375 male recruits and 138 female recruits, carried out basic training in the Israeli anti-aircraft corps between November 1999 and January 2003. Each battery was monitored prospectively for 10 weeks of a basic training course. During that time, recruits who were suspected of having an overuse injury went through a protocol that included an orthopedic specialist physical examination followed by a radionuclide technetium bone scan, which was assessed by consultant nuclear medicine experts. The assessment included the anatomic site and the severity of the fractures, labeled as either high severity or low severity. Stress fractures were significantly more common among female recruits than among male recruits. A total of 42 male (11.2%) and 33 female (23.91%) recruits had positive bone scans for stress fractures (female:male relative ratio, 2.13; p < 0.001). Pelvic, femur, and tibia fractures were significantly more common among female recruits than among male recruits (p < 0.005). Female recruits had significantly more severe fractures in the tibia (p < 0.05). However, there was no significant difference in the severity of stress fractures in the femur or metatarsals between male and female recruits, as assessed by radionuclide uptake. We recommend that different training programs be assigned according to gender, in which female recruits would have a lower level of target strain or a more moderate

  20. Relationships among in-situ stress, fractures and faults, and fluid flow: Monterey formation, Santa Maria Basin, California

    Finkbeiner, T.; Barton, C.A.; Zoback, M.D.

    1997-01-01

    We used borehole televiewer (BHTV) data from four wells within the onshore and offshore Santa Maria basin, California, to investigate the relationships among fracture distribution, orientation, and variation with depth and in-situ stress. Our analysis of stress-induced well-bore breakouts shows a uniform northeast maximum horizontal stress (SH max) orientation in each well. This direction is consistent with the SH max direction determined from well-bore breakouts in other wells in this region, the northwest trend of active fold axes, and kinematic inversion of nearby earthquake focal plane mechanisms. In contrast to the uniformity of the stress field, fracture orientation, dip, and frequency vary considerably from well to well and within each well. With depth, fractures can be divided into distinct subsets on the basis of fracture frequency and orientation, which correlate with changes of lithology and physical properties. Although factors such as tectonic history, diagenesis, and structural variations obviously have influenced fracture distribution, integration of the in-situ stress and fracture data sets indicates that many of the fractures, faults, and bedding planes are active, small-scale strike-slip and reverse faults in the current northeast-trending transpressive stress field. In fact, we observed local breakout rotations in the wells, providing kinematic evidence for recent shear motion along fracture and bedding-parallel planes. Only in the onshore well do steeply dipping fractures strike parallel to SHmax. Drill-stem tests from two of the offshore wells indicate that formation permeability is greatly enhanced in sections of the wells where fractures are favorably oriented for shear failure in the modern stress field. Thus, relatively small-scale active faults provide important conduits along which fluids migrate.

  1. Stress corrosion-controlled rates of mode I fracture propagation in calcareous bedrock

    NASA Astrophysics Data System (ADS)

    Voigtlaender, Anne; Leith, Kerry; Krautblatter, Michael

    2014-05-01

    Surface bedrock on natural rock slopes is subject to constant and cyclic environmental stresses (wind, water, wave, ice, seismic or gravitational). Studies indicate that these stresses range up to several hundred kPa, generally too low to cause macroscopic changes in intact rock, although clear evidence of fracture generation, crack propagation and weathering of bedrock illustrates the effect of environmental stresses at the Earth's surface. We suggest that material degradation and its extent, is likely to be controlled by the rate of stress corrosion cracking (SCC). Stress corrosion is a fluid-material reaction, where fluids preferentially react with strained atomic bonds at the tip of developing fractures. Stress corrosion in ferrous and siliceous materials is often accepted as the fracture propagation and degradation rate-controlling process where materials are subject to stresses and fluids. Although evidence for chemical weathering in propagating bedrock fractures is clear in natural environments, the physical system and quantification of stress corrosion in natural rocks is yet to be addressed. Here, we present preliminary data on the relationship between stresses at levels commonly present on natural rock slopes, and material damage resulting from stress corrosion under constant or cyclic tensile loading. We undertake single notch three-point bending tests (SNBT) on fresh calcareous bedrock specimens (1100x100x100mm) over a two-month period. Two beams containing an artificial notch are stressed to 75% of their ultimate strength, and a constant supply of weak acid is applied at the notch tip to enhance chemical reactions. A third, unloaded, beam is also exposed to weak acid in order to elucidate the contribution of stress corrosion cracking to the material degradation. Stresses at the tip of propagating cracks affect the kinetics of the chemical reaction in the specimen exposed to both loading and corrosion, leading to an increase in degradation, and greater

  2. Association between Global Biomarkers of Oxidative Stress and Hip Fracture in Postmenopausal Women: A Prospective Study

    PubMed Central

    Yang, Shuman; Feskanich, Diane; Willett, Walter C.; Eliassen, A. Heather; Wu, Tianying

    2014-01-01

    Human studies suggest that oxidative stress is a risk factor for osteoporosis, but its relationship with fracture risk is poorly understood. The purpose of the present study was to investigate the association between biomarkers of oxidative stress and hip fracture in postmenopausal women. We conducted a prospective study in the Nurses’ Health Study among 996 women aged 60 years or older at baseline blood collection in 1989–1990. Plasma fluorescent oxidation products (FlOPs) were measured at three excitation/emission wavelengths (360/420 nm named as FlOP_360; 320/420 nm named as FlOP_320 and 400/475 nm named as FlOP_400). FlOPs are generated from many different pathways (lipid, protein and DNA) and reflect a global oxidation burden. FlOP assay is 10–100 times more sensitive than measurement of malondialdehyde. We used Cox proportional hazards regression model to investigate the association between baseline plasma FlOPs and risk of hip fracture, adjusting for multiple hip fracture risk factors such as age, history of osteoporosis, history of hypertension, prior fracture and smoking status. Forty four hip fractures (4.4%) were identified during the follow-up (Maximum = 23 years). In the multivariable model, the hazard ratios (HR) of hip fracture in the second and third tertiles of FlOP_320 were 2.11 (95% confidence interval [CI] = 0.88–5.10) and 2.67 (95% CI = 1.14–6.27), respectively, in comparison with the lowest tertile, and the risk increased linearly with increasing FlOP_320 (P for trend = 0.021). Neither FlOP_360 nor FlOP_400 was significantly associated with risk of hip fracture (Tertile 3 versus tertile 1: HR = 0.70, 95% CI = 0.32–1.54, P for trend = 0.386 for FlOP_360; and HR = 0.88, 95% CI = 0.40–1.96, P for trend = 0.900 for FlOP_400). In this prospective study, higher plasma FlOP_320 was an independent risk factor for hip fracture. Our results need further confirmation. PMID:24957524

  3. Association between global biomarkers of oxidative stress and hip fracture in postmenopausal women: a prospective study.

    PubMed

    Yang, Shuman; Feskanich, Diane; Willett, Walter C; Eliassen, A Heather; Wu, Tianying

    2014-12-01

    Human studies suggest that oxidative stress is a risk factor for osteoporosis, but its relationship with fracture risk is poorly understood. The purpose of the present study was to investigate the association between biomarkers of oxidative stress and hip fracture in postmenopausal women. We conducted a prospective study in the Nurses' Health Study among 996 women aged 60 years or older at baseline blood collection in 1989-1990. Plasma fluorescent oxidation products (FlOPs) were measured at three excitation/emission wavelengths (360/420 nm named as FlOP_360; 320/420 nm named as FlOP_320; and 400/475 nm named as FlOP_400). FlOPs are generated from many different pathways (lipid, protein, and DNA) and reflect a global oxidation burden. FlOP assay is 10-100 times more sensitive than measurement of malondialdehyde. We used Cox proportional hazards regression model to investigate the association between baseline plasma FlOPs and the risk of hip fracture, adjusting for multiple hip fracture risk factors such as age, history of osteoporosis, history of hypertension, prior fracture, and smoking status. Forty-four hip fractures (4.4%) were identified during the follow-up (maximum = 23 years). In the multivariable model, the hazard ratios (HRs) of hip fracture in the second and third tertiles of FlOP_320 were 2.11 (95% confidence interval [CI] = 0.88-5.10) and 2.67 (95% CI = 1.14-6.27), respectively, in comparison with the lowest tertile, and the risk increased linearly with increasing FlOP_320 (p for trend = 0.021). Neither FlOP_360 nor FlOP_400 was significantly associated with risk of hip fracture (tertile 3 versus tertile 1: HR = 0.70, 95% CI = 0.32-1.54, p for trend = 0.386 for FlOP_360; and HR = 0.88, 95% CI = 0.40-1.96, p for trend = 0.900 for FlOP_400). In this prospective study, higher plasma FlOP_320 was an independent risk factor for hip fracture. Our results need further confirmation. © 2014 American Society for Bone

  4. Plate Versus Intramedullary Nail Fixation of Anterior Tibial Stress Fractures: A Biomechanical Study.

    PubMed

    Markolf, Keith L; Cheung, Edward; Joshi, Nirav B; Boguszewski, Daniel V; Petrigliano, Frank A; McAllister, David R

    2016-06-01

    Anterior midtibial stress fractures are an important clinical problem for patients engaged in high-intensity military activities or athletic training activities. When nonoperative treatment has failed, intramedullary (IM) nail and plate fixation are 2 surgical options used to arrest the progression of a fatigue fracture and allow bone healing. A plate will be more effective than an IM nail in preventing the opening of a simulated anterior midtibial stress fracture from tibial bending. Controlled laboratory study. Fresh-frozen human tibias were loaded by applying a pure bending moment in the sagittal plane. Thin transverse saw cuts, 50% and 75% of the depth of the anterior tibial cortex, were created at the midtibia to simulate a fatigue fracture. An extensometer spanning the defect was used to measure the fracture opening displacement (FOD) before and after the application of IM nail and plate fixation constructs. IM nails were tested without locking screws, with a proximal screw only, and with proximal and distal screws. Plates were tested with unlocked bicortical screws (standard compression plate) and locked bicortical screws; both plate constructs were tested with the plate edge placed 1 mm from the anterior tibial crest (anterior location) and 5 mm posterior to the crest. For the 75% saw cut depth, the mean FOD values for all IM nail constructs were 13% to 17% less than those for the saw cut alone; the use of locking screws had no significant effect on the FOD. The mean FOD values for all plate constructs were significantly less than those for all IM nail constructs. The mean FOD values for all plates were 28% to 46% less than those for the saw cut alone. Anterior plate placement significantly decreased mean FOD values for both compression and locked plate constructs, but the mean percentage reductions for locked and unlocked plates were not significantly different from each other for either plate placement. The percentage FOD reductions for all plate

  5. Distribution of stress drop, stiffness, and fracture energy over earthquake rupture zones

    Fletcher, Joe B.; McGarr, A.

    2006-01-01

    Using information provided by slip models and the methodology of McGarr and Fletcher (2002), we map static stress drop, stiffness (k = ????/u, where ???? is static stress drop and u is slip), and fracture energy over the slip surface to investigate the earthquake rupture process and energy budget. For the 1994 M6.7 Northridge, 1992 M7.3 Landers, and 1995 M6.9 Kobe earthquakes, the distributions of static stress drop show strong heterogeneity, emphasizing the importance of asperities in the rupture process. Average values of static stress drop are 17, 11, and 4 Mpa for Northridge, Landers, and Kobe, respectively. These values are substantially higher than estimates based on simple crack models, suggesting that the failure process involves the rupture of asperities within the larger fault zone. Stress drop as a function of depth for the Northridge and Landers earthquakes suggests that stress drops are limited by crustal strength. For these two earthquakes, regions of high slip are surrounded by high values of stiffness. Particularly for the Northridge earthquake, the prominent patch of high slip in the central part of the fault is bordered by a ring of high stiffness and is consistent with expectations based on the failure of an asperity loaded at its edge due to exterior slip. Stiffness within an asperity is inversely related to its dimensions. Estimates of fracture energy, based on static stress drop, slip, and rupture speed, were used to investigate the nature of slip weakening at four locations near the hypocenter of the Kobe earthquake for comparison with independent results based on a dynamic model of this earthquake. One subfault updip and to the NE of the hypocenter has a fracture energy of 1.1 MJ/m2 and a slip-weakening distance, Dc, of 0.66 m. Right triangles, whose base and height are Dc and the dynamic stress drop, respectively, approximately overlie the slip-dependent stress given by Ide and Takeo (1997) for the same locations near the hypocenter. The

  6. Tibial plateau fracture following gracilis-semitendinosus anterior cruciate ligament reconstruction: The tibial tunnel stress-riser.

    PubMed

    Sundaram, R O; Cohen, D; Barton-Hanson, N

    2006-06-01

    Tibial plateau fractures following anterior cruciate ligament (ACL) reconstruction are extremely rare. This is the first reported case of a tibial plateau fracture following four-strand gracilis-semitendinosus autograft ACL reconstruction. The tibial tunnel alone may behave as a stress riser which can significantly reduce bone strength.

  7. Bone strength estimates relative to vertical ground reaction force discriminates women runners with stress fracture history.

    PubMed

    Popp, Kristin L; McDermott, William; Hughes, Julie M; Baxter, Stephanie A; Stovitz, Steven D; Petit, Moira A

    2017-01-01

    To determine differences in bone geometry, estimates of bone strength, muscle size and bone strength relative to load, in women runners with and without a history of stress fracture. We recruited 32 competitive distance runners aged 18-35, with (SFX, n=16) or without (NSFX, n=16) a history of stress fracture for this case-control study. Peripheral quantitative computed tomography (pQCT) was used to assess volumetric bone mineral density (vBMD, mg/mm 3 ), total (ToA) and cortical (CtA) bone areas (mm 2 ), and estimated compressive bone strength (bone strength index; BSI, mg/mm 4 ) at the distal tibia. ToA, CtA, cortical vBMD, and estimated strength (section modulus; Zp, mm 3 and strength strain index; SSIp, mm 3 ) were measured at six cortical sites along the tibia. Mean active peak vertical (pkZ) ground reaction forces (GRFs), assessed from a fatigue run on an instrumented treadmill, were used in conjunction with pQCT measurements to estimate bone strength relative to load (mm 2 /N∗kg -1 ) at all cortical sites. SSIp and Zp were 9-11% lower in the SFX group at mid-shaft of the tibia, while ToA and vBMD did not differ between groups at any measurement site. The SFX group had 11-17% lower bone strength relative to mean pkZ GRFs (p<0.05). These findings indicate that estimated bone strength at the mid-tibia and mean pkZ GRFs are lower in runners with a history of stress fracture. Bone strength relative to load is also lower in this same region suggesting that strength deficits in the middle 1/3 of the tibia and altered gait biomechanics may predispose an individual to stress fracture. Copyright © 2016. Published by Elsevier Inc.

  8. Stress fracture of the proximal humeral epiphysis in an elite junior badminton player.

    PubMed Central

    Boyd, K T; Batt, M E

    1997-01-01

    An elite junior badminton player presented with a chronic painful dominant shoulder after an intense training course. An acute stress fracture to the proximal humeral epiphysis was found. Two-plane radiography will identify abnormalities of the growth plate but comparative films of the unaffected side may also be required to differentiate subtle changes. Rest with subsequent rehabilitation is the appropriate management of these injuries although ideally they should be subjected to primary prevention. Images Figure 1 Figure 2 PMID:9298564

  9. Stress fracture of the second metacarpal bone in a badminton player.

    PubMed

    Fukuda, Koji; Fujioka, Hiroyuki; Fujita, Ikuo; Uemoto, Harunobu; Hiranaka, Takafumi; Tsuji, Mitsuo; Kurosaka, Masahiro

    2008-07-18

    We present a rare case of stress fracture of the second metacarpal bone. A 14-year-old girl felt pain on the dorsal aspect of the right wrist without any history of major trauma, when she played a smash during a game of badminton. On the radiographs, periosteal reaction was detected on the ulnar aspect of the base of the second metacarpal bone. She was treated conservatively and she returned to the original activity level.

  10. Ground reaction forces and bone parameters in females with tibial stress fracture.

    PubMed

    Bennell, Kim; Crossley, Kay; Jayarajan, Jyotsna; Walton, Elizabeth; Warden, Stuart; Kiss, Z Stephen; Wrigley, Tim

    2004-03-01

    Tibial stress fracture is a common overuse running injury that results from the interplay of repetitive mechanical loading and bone strength. This research project aimed to determine whether female runners with a history of tibial stress fracture (TSF) differ in ground reaction force (GRF) parameters during running, regional bone density, and tibial bone geometry from those who have never sustained a stress fracture (NSF). Thirty-six female running athletes (13 TSF; 23 NSF) ranging in age from 18 to 44 yr were recruited for this cross-sectional study. The groups were well matched for demographic, training, and menstrual parameters. A force platform measured selected GRF parameters (peak and time to peak for vertical impact and active forces, and horizontal braking and propulsive forces) during overground running at 4.0 m.s.(-1). Lumbar spine, proximal femur, and distal tibial bone mineral density were assessed by dual energy x-ray absorptiometry. Tibial bone geometry (cross-sectional dimensions and areas, and second moments of area) was calculated from a computerized tomography scan at the junction of the middle and distal thirds. There were no significant differences between the groups for any of the GRF, bone density, or tibial bone geometric parameters (P > 0.05). Both TSF and NSF subjects had bone density levels that were average or above average compared with a young adult reference range. Factor analysis followed by discriminant function analysis did not find any combinations of variables that differentiated between TSF and NSF groups. These findings do not support a role for GRF, bone density, or tibial bone geometry in the development of tibial stress fractures, suggesting that other risk factors were more important in this cohort of female runners.

  11. Bone geometry, strength, and muscle size in runners with a history of stress fracture.

    PubMed

    Popp, Kristin L; Hughes, Julie M; Smock, Amanda J; Novotny, Susan A; Stovitz, Steven D; Koehler, Scott M; Petit, Moira A

    2009-12-01

    Our primary aim was to explore differences in estimates of tibial bone strength, in female runners with and without a history of stress fractures. Our secondary aim was to explore differences in bone geometry, volumetric density, and muscle size that may explain bone strength outcomes. A total of 39 competitive distance runners aged 18-35 yr, with (SFX, n = 19) or without (NSFX, n = 20) a history of stress fracture were recruited for this cross-sectional study. Peripheral quantitative computed tomography (XCT 3000; Orthometrix, White Plains, NY) was used to assess volumetric bone mineral density (vBMD, mg x mm(-3)), bone area (ToA, mm(2)), and estimated compressive bone strength (bone strength index (BSI) = ToA x total volumetric density (ToD(2))) at the distal tibia (4%). Total (ToA, mm(2)) and cortical (CoA, mm(2)) bone area, cortical vBMD, and estimated bending strength (strength-strain index (SSIp), mm(3)) were measured at the 15%, 25%, 33%, 45%, 50%, and 66% sites. Muscle cross-sectional area (MCSA) was measured at the 50% and 66% sites. Participants in the SFX group had significantly smaller (7%-8%) CoA at the 45%, 50%, and 66% sites (P stress fracture. However, the lower strength was appropriate for the smaller muscle size, suggesting that interventions to reduce stress fracture risk might be aimed at improving muscle size and strength.

  12. Hydrologic effects of stress-relief fracturing in an Appalachian Valley

    Wyrick, Granville G.; Borchers, James W.

    1981-01-01

    being formed from stress relief. As stress-relief fractures have been described in other valleys of the Appalachian Plateaus, the same aquifer conditions may exist in those valleys.

  13. Analysis of foot structure in athletes sustaining proximal fifth metatarsal stress fracture.

    PubMed

    Hetsroni, Iftach; Nyska, Meir; Ben-Sira, David; Mann, Gideon; Segal, Ofer; Maoz, Guy; Ayalon, Moshe

    2010-03-01

    In the past, several studies provided anecdotal descriptions of high-arched feet in individuals sustaining proximal fifth metatarsal stress fractures. This relationship has never been supported by scientific evidence. Our objective was to examine whether athletes who sustained this injury had an exceptional static foot structure or dynamic loading pattern. Ten injured professional soccer players who regained full professional activity following a unilateral proximal fifth metatarsal stress fracture and ten control soccer players were examined. Independent variables included static evaluation of foot and arch structure, followed by dynamic plantar foot pressure evaluation. Each variable was compared between injured, contra-lateral uninjured, and control feet. Static measurements of foot and arch structure did not reveal differences among the groups. However, plantar pressure evaluation revealed relative unloading of the fourth metatarsal in injured and uninjured limbs of injured athletes compared with control, while the fifth metatarsal revealed pressure reduction only in the injured limbs of injured athletes. Athletes who sustained proximal fifth metatarsal stress fracture were not characterized by an exceptional static foot structure. Dynamically, lateral metatarsal unloading during stance may either play a role in the pathogenesis of the injury, or alternately represent an adaptive process. Footwear fabrication for previously injured athletes should not categorically address cushioning properties designed for high-arch feet, but rather focus on individual dynamic evaluation of forefoot loading, with less attention applied to static foot and arch characteristics.

  14. Stress fractures of the base of the metatarsal bones in young trainee ballet dancers

    PubMed Central

    Albisetti, Walter; De Bartolomeo, Omar; Tagliabue, Lorenzo; Camerucci, Emanuela; Calori, Giorgio Maria

    2009-01-01

    Classical ballet is an art form requiring extraordinary physical activity, characterised by rigorous training. These can lead to many overuse injuries arising from repetitive minor trauma. The purpose of this paper is to report our experience in the diagnosis and treatment of stress fractures at the base of the second and third metatarsal bones in young ballet dancers. We considered 150 trainee ballet dancers from the Ballet Schools of "Teatro Alla Scala" of Milan from 2005 to 2007. Nineteen of them presented with stress fractures of the base of the metatarsal bones. We treated 18 dancers with external shockwave therapy (ESWT) and one with pulsed electromagnetic fields (EMF) and low-intensity ultrasound (US); all patients were recommended rest. In all cases good results were obtained. The best approach to metatarsal stress fractures is to diagnose them early through clinical examination and then through X-ray and MRI. ESWT gave good results, with a relatively short time of rest from the patients’ activities and a return to dancing without pain. PMID:19415273

  15. Predisposing Risk Factors and Stress Fractures in Division I Cross Country Runners.

    PubMed

    Giffin, Kaci L; Knight, Kathy B; Bass, Martha A; Valliant, Melinda W

    2017-11-11

    The purpose of this study was to explore factors associated with increased stress fractures in collegiate cross country runners. Participants in this study were 42 male and female cross country runners at a Division I university. Each athlete completed a questionnaire regarding smoking status, vitamin/mineral intake, previous stress fracture history, birth control usage, menstrual status, and demographic information. Nutritional assessment via a 3-day food record and measurements of whole body, lumbar spine, and hip bone mineral densities (BMD) were also conducted on each athlete. Results indicated that 40% of the female and 35% of the male runners reported a history of stress fracture, and that all of these did not meet the recommended daily energy intake or adequate intakes for calcium or Vitamin D required for their amount of training. Two-tailed t-test found statistically higher incidences of lumbar spine BMD in males and females whose daily calcium and Vitamin D intakes were below minimum requirements as well as for women whose caloric intake was below the required level. When data on the lumbar spine was evaluated, 31% of participants (31.8% of the male and 30% of the female runners) were identified as having osteopenia and 4.8% with osteoporosis. Results warrant a need for future longitudinal studies.

  16. Ankle stress test for predicting the need for surgical fixation of isolated fibular fractures.

    PubMed

    Egol, Kenneth A; Amirtharajah, Mohana; Amirtharage, Mohana; Tejwani, Nirmal C; Capla, Edward L; Koval, Kenneth J

    2004-11-01

    The purpose of this study was to confirm the prevalence of medial ankle widening among patients with an isolated fibular fracture and to determine the functional outcome of nonoperative treatment despite a diagnosis of a supination-external rotation stage-IV injury based on stress radiography. One hundred and one patients with evidence of an isolated fibular fracture and an intact mortise seen on a standard ankle trauma radiograph series were evaluated with stress radiographs. Clinical signs were recorded at the time of presentation. A positive stress test was defined as > or =4 mm of widening of the medial clear space. Patients with a negative stress test were treated nonoperatively, those with a positive stress test and clinical signs of medial injury were treated surgically, and those with a positive stress test and no signs of medial injury were treated according to the preference of the surgeon and patient. The patients were followed prospectively with radiographs and ankle outcome scores. Sixty-six (65%) of the 101 patients had a positive stress radiograph. Thirty-six of them had signs of medial injury, and thirty had no medial injury. With regard to predicting a positive stress radiograph, medial tenderness had a sensitivity of 56% and a specificity of 80%, swelling had a sensitivity of 55% and a specificity of 71%, and ecchymosis had a sensitivity of 26% and a specificity of 91%. Of the subset of patients without signs of medial injury, twenty were treated nonoperatively (group I) and ten were treated operatively (group II). Two of the twenty patients in group I had evidence of persistent widening of the medial clear space at the time of the latest follow-up (mean, 7.4 months); only one of those patients was symptomatic. The average American Orthopaedic Foot and Ankle Society (AOFAS) score was 94 points in group I and 93 points in group II. We found a high rate of positive stress radiographs for patients who presented with an isolated fibular fracture and

  17. In-situ stress and fracture permeability in a fault-hosted geothermal reservoir at Dixie Valley, Nevada

    Hickman, Stephen; Barton, Colleen; Zoback, Mark; Morin, Roger; Sass, John; Benoit, Richard; ,

    1997-01-01

    As part of a study relating fractured rock hydrology to in-situ stress and recent deformation within the Dixie Valley Geothermal Field, borehole televiewer logging and hydraulic fracturing stress measurements were conducted in a 2.7-km-deep geothermal production well (73B-7) drilled into the Stillwater fault zone. Borehole televiewer logs from well 73B-7 show numerous drilling-induced tensile fractures, indicating that the direction of the minimum horizontal principal stress, Shmin, is S57 ??E. As the Stillwater fault at this location dips S50 ??E at approximately 3??, it is nearly at the optimal orientation for normal faulting in the current stress field. Analysis of the hydraulic fracturing data shows that the magnitude of Shmin is 24.1 and 25.9 MPa at 1.7 and 2.5 km, respectively. In addition, analysis of a hydraulic fracturing test from a shallow well 1.5 km northeast of 73B-7 indicates that the magnitude of Shmin is 5.6 MPa at 0.4 km depth. Coulomb failure analysis shows that the magnitude of Shmin in these wells is close to that predicted for incipient normal faulting on the Stillwater and subparallel faults, using coefficients of friction of 0.6-1.0 and estimates of the in-situ fluid pressure and overburden stress. Spinner flowmeter and temperature logs were also acquired in well 73B-7 and were used to identify hydraulically conductive fractures. Comparison of these stress and hydrologic data with fracture orientations from the televiewer log indicates that hydraulically conductive fractures within and adjacent to the Stillwater fault zone are critically stressed, potentially active normal faults in the current west-northwest extensional stress regime at Dixie Valley.

  18. Prevention of lower extremity stress fractures: a controlled trial of a shock absorbent insole.

    PubMed Central

    Gardner, L I; Dziados, J E; Jones, B H; Brundage, J F; Harris, J M; Sullivan, R; Gill, P

    1988-01-01

    A prospective controlled trial was carried out to determine the usefulness of a viscoelastic polymer insole in prevention of stress fractures and stress reactions of the lower extremities. The subjects were 3,025 US Marine recruits who were followed for 12 weeks of training at Parris Island, South Carolina. Polymer and standard mesh insoles were systematically distributed in boots that were issued to members of odd and even numbered platoons. The most important finding was that an elastic polymer insole with good shock absorbency properties did not prevent stress reactions of bone during a 12-week period of vigorous physical training. To control for the confounding effects of running in running shoes, which occurred for about one and one-half hours per week for the first five weeks, we also examined the association of age of shoes and cost of shoes with injury incidence. A slight trend of increasing stress injuries by increasing age of shoes was observed. However, this trend did not account for the similarity of rates in the two insole groups. In addition, we observed a strong trend of decreasing stress injury rate by history of increasing physical activity, as well as a higher stress injury rate in White compared to Black recruits. The results of the trial were not altered after controlling for these factors. This prospective study confirms previous clinical reports of the association of stress fractures with physical activity history. The clinical application of a shock absorbing insole as a preventive for lower extremity stress reactions is not supported in these uniformly trained recruits. The findings are relevant to civilian populations. PMID:3056045

  19. ADDITIONAL STRESS AND FRACTURE MECHANICS ANALYSES OF PRESSURIZED WATER REACTOR PRESSURE VESSEL NOZZLES

    SciT

    Walter, Matthew; Yin, Shengjun; Stevens, Gary

    2012-01-01

    In past years, the authors have undertaken various studies of nozzles in both boiling water reactors (BWRs) and pressurized water reactors (PWRs) located in the reactor pressure vessel (RPV) adjacent to the core beltline region. Those studies described stress and fracture mechanics analyses performed to assess various RPV nozzle geometries, which were selected based on their proximity to the core beltline region, i.e., those nozzle configurations that are located close enough to the core region such that they may receive sufficient fluence prior to end-of-life (EOL) to require evaluation of embrittlement as part of the RPV analyses associated with pressure-temperaturemore » (P-T) limits. In this paper, additional stress and fracture analyses are summarized that were performed for additional PWR nozzles with the following objectives: To expand the population of PWR nozzle configurations evaluated, which was limited in the previous work to just two nozzles (one inlet and one outlet nozzle). To model and understand differences in stress results obtained for an internal pressure load case using a two-dimensional (2-D) axi-symmetric finite element model (FEM) vs. a three-dimensional (3-D) FEM for these PWR nozzles. In particular, the ovalization (stress concentration) effect of two intersecting cylinders, which is typical of RPV nozzle configurations, was investigated. To investigate the applicability of previously recommended linear elastic fracture mechanics (LEFM) hand solutions for calculating the Mode I stress intensity factor for a postulated nozzle corner crack for pressure loading for these PWR nozzles. These analyses were performed to further expand earlier work completed to support potential revision and refinement of Title 10 to the U.S. Code of Federal Regulations (CFR), Part 50, Appendix G, Fracture Toughness Requirements, and are intended to supplement similar evaluation of nozzles presented at the 2008, 2009, and 2011 Pressure Vessels and Piping (PVP

  20. Residual stress and damage-induced critical fracture on CO2 laser treated fused silica

    NASA Astrophysics Data System (ADS)

    Matthews, M. J.; Stolken, J. S.; Vignes, R. M.; Norton, M. A.; Yang, S.; Cooke, J. D.; Guss, G. M.; Adams, J. J.

    2009-10-01

    Localized damage repair and polishing of silica-based optics using mid- and far-IR CO2 lasers has been shown to be an effective method for increasing optical damage threshold in the UV. However, it is known that CO2 laser heating of silicate surfaces can lead to a level of residual stress capable of causing critical fracture either during or after laser treatment. Sufficient control of the surface temperature as a function of time and position is therefore required to limit this residual stress to an acceptable level to avoid critical fracture. In this work we present the results of 351 nm, 3ns Gaussian damage growth experiments within regions of varying residual stress caused by prior CO2 laser exposures. Thermally stressed regions were non-destructively characterized using polarimetry and confocal Raman microscopy to measure the stress induced birefringence and fictive temperature respectively. For 1~40s square pulse CO2 laser exposures created over 0.5-1.25kW/cm2 with a 1-3mm 1/e2 diameter beam (Tmax~1500-3000K), the critical damage site size leading to fracture increases weakly with peak temperature, but shows a stronger dependence on cooling rate, as predicted by finite element hydrodynamics simulations. Confocal micro-Raman was used to probe structural changes to the glass over different thermal histories and indicated a maximum fictive temperature of 1900K for Tmax>=2000K. The effect of cooling rate on fictive temperature caused by CO2 laser heating are consistent with finite element calculations based on a Tool-Narayanaswamy relaxation model.

  1. Normative calcaneal quantitative ultrasound data for the indigenous Shuar and non-Shuar Colonos of the Ecuadorian Amazon.

    PubMed

    Madimenos, Felicia C; Snodgrass, J Josh; Blackwell, Aaron D; Liebert, Melissa A; Cepon, Tara J; Sugiyama, Lawrence S

    2011-01-01

    Minimal data on bone mineral density changes are available from populations in developing countries. Using calcaneal quantitative ultrasound (QUS) techniques, the current study contributes to remedying this gap in the literature by establishing a normative data set on the indigenous Shuar and non-Shuar Colonos of the Ecuadorian Amazon. The paucity of bone mineral density (BMD) data from populations in developing countries partially reflects the lack of diagnostic resources in these areas. Portable QUS techniques now enable researchers to collect bone health data in remote field-based settings and to contribute normative data from developing regions. The main objective of this study is to establish normative QUS data for two Ecuadorian Amazonian populations-the indigenous Shuar and non-Shuar Colonos. The effects of ethnic group, sex, age, and body size on QUS parameters are also considered. A study cohort consisting of 227 Shuar and 261 Colonos (15-91 years old) were recruited from several small rural Ecuadorian communities in the Upano River Valley. Calcaneal QUS parameters were collected on the right heel of each participant using a Sahara bone sonometer. Three ultrasound generated parameters were employed: broadband ultrasound attenuation (BUA), speed of sound (SOS), and calculated heel BMD (hBMD). In both populations and sexes, all QUS values were progressively lower with advancing age. Shuar have significantly higher QUS values than Colonos, with most pronounced differences found between pre-menopausal Shuar and Colono females. Multiple regression analyses show that age is a key predictor of QUS while weight alone is a less consistent determinant. Both Shuar males and females display comparatively greater QUS parameters than other reference populations. These normative data for three calcaneal QUS parameters will be useful for predicting fracture risk and determining diagnostic QUS criteria of osteoporosis in non-industrialized populations in South America and

  2. Short-term effects of teriparatide versus placebo on bone biomarkers, structure, and fracture healing in women with lower-extremity stress fractures: A pilot study.

    PubMed

    Almirol, Ellen A; Chi, Lisa Y; Khurana, Bharti; Hurwitz, Shelley; Bluman, Eric M; Chiodo, Christopher; Matzkin, Elizabeth; Baima, Jennifer; LeBoff, Meryl S

    2016-09-01

    In this pilot, placebo-controlled study, we evaluated whether brief administration of teriparatide (TPTD) in premenopausal women with lower-extremity stress fractures would increase markers of bone formation in advance of bone resorption, improve bone structure, and hasten fracture healing according to magnetic resonance imaging (MRI). Premenopausal women with acute lower-extremity stress fractures were randomized to injection of TPTD 20-µg subcutaneous (s.c.) (n = 6) or placebo s.c. (n = 7) for 8 weeks. Biomarkers for bone formation N-terminal propeptide of type I procollagen (P1NP) and osteocalcin (OC) and resorption collagen type-1 cross-linked C-telopeptide (CTX) and collagen type 1 cross-linked N-telopeptide (NTX) were measured at baseline, 4 and 8 weeks. The area between the percent change of P1NP and CTX over study duration is defined as the anabolic window. To assess structural changes, peripheral quantitative computed topography (pQCT) was measured at baseline, 8 and 12 weeks at the unaffected tibia and distal radius. The MRI of the affected bone assessed stress fracture healing at baseline and 8 weeks. After 8 weeks of treatment, bone biomarkers P1NP and OC increased more in the TPTD- versus placebo-treated group (both p ≤ 0.01), resulting in a marked anabolic window (p ≤ 0.05). Results from pQCT demonstrated that TPTD-treated women showed a larger cortical area and thickness compared to placebo at the weight bearing tibial site, while placebo-treated women had a greater total tibia and cortical density. No changes at the radial sites were observed between groups. According to MRI, 83.3% of the TPTD- and 57.1% of the placebo-treated group had improved or healed stress fractures (p = 0.18). In this randomized, pilot study, brief administration of TPTD showed anabolic effects that TPTD may help hasten fracture healing in premenopausal women with lower-extremity stress fractures. Larger prospective studies are warranted to determine

  3. Completed Ulnar Shaft Stress Fracture in a Fast-Pitch Softball Pitcher.

    PubMed

    Wiltfong, Roger E; Carruthers, Katherine H; Popp, James E

    2017-03-01

    Stress fractures of the upper extremity have been previously described in the literature, yet reports of isolated injury to the ulna diaphysis or olecranon are rare. The authors describe a case involving an 18-year-old fast-pitch softball pitcher. She presented with a long history of elbow and forearm pain, which was exacerbated during a long weekend of pitching. Her initial physician diagnosed her as having forearm tendinitis. She was treated with nonsurgical means including rest, anti-inflammatory medications, therapy, and kinesiology taping. She resumed pitching when allowed and subsequently had an acute event immediately ceasing pitching. She presented to an urgent care clinic that evening and was diagnosed as having a complete ulnar shaft fracture subsequently needing surgical management. This case illustrates the need for a high degree of suspicion for ulnar stress fractures in fast-pitch soft-ball pitchers with an insidious onset of unilateral forearm pain. Through early identification and intervention, physicians may be able to reduce the risk of injury progression and possibly eliminate the need for surgical management. [Orthopedics. 2017; 40(2):e360-e362.]. Copyright 2016, SLACK Incorporated.

  4. Treatment of stress fracture of the olecranon in throwing athletes with internal fixation through a small incision

    PubMed Central

    2012-01-01

    The present study is a report of retrospective case series of stress fracture of the olecranon. Six patients presented posterior elbow pain in throwing in baseball and softball, but fracture was not diagnosed in radiographs. We detected stress fracture of the olecranon using computed tomographic (CT) scan and treated the patient with internal fixation with a headless cannulated double threaded screw through a small skin incision. All patients returned to competitive level without elbow complaints after the operation. When throwing athletes present with unusual posterior elbow pain and no significant findings on radiographs, a CT scan examination should be performed. We recommend surgical treatment of internal fixation with a screw through a small skin incision, as a good option for stress fracture of the olecranon in order to allow early return to sports activity in competitive athletes. PMID:23241173

  5. Fibrolipomatous hamartoma of the inferior calcaneal nerve (Baxter nerve).

    PubMed

    Zeng, Rong; Frederick-Dyer, Katherine; Ferguson, N Lynn; Lewis, James; Fu, Yitong

    2012-09-01

    Fibrolipomatous hamartoma (FLH) is a rare, benign lesion of the peripheral nerves most frequently involving the median nerve and its digital branches (80 %). Pathognomonic MR features of FLH such as coaxial-cable-like appearance on axial planes and a spaghetti-like appearance on coronal planes have been described by Marom and Helms, obviating the need for diagnostic biopsy. We present a case of fibrolipomatous hamartoma of the inferior calcaneal nerve (Baxter nerve) with associated subcutaneous fat proliferation.

  6. Low serum 25-hydroxyvitamin D is associated with increased risk of stress fracture during Royal Marine recruit training.

    PubMed

    Davey, T; Lanham-New, S A; Shaw, A M; Hale, B; Cobley, R; Berry, J L; Roch, M; Allsopp, A J; Fallowfield, J L

    2016-01-01

    The aim of this study was to investigate vitamin D status and stress fracture risk during Royal Marine military training. Poor vitamin D status was associated with an increased risk of stress fracture. Vitamin D supplementation may help to reduce stress fracture risk in male military recruits with low vitamin D status. Stress fracture is a common overuse injury in military recruits, including Royal Marine (RM) training in the UK. RM training is recognised as one of the most arduous basic training programmes in the world. Associations have been reported between serum 25-hydroxyvitamin D (25(OH)D) and risk of stress fracture, but the threshold of 25(OH)D for this effect remains unclear. We aimed to determine if serum 25(OH)D concentrations were associated with stress fracture risk during RM training. We prospectively followed 1082 RM recruits (males aged 16-32 years) through the 32-week RM training programme. Troops started training between September and July. Height, body weight and aerobic fitness were assessed at week 1. Venous blood samples were drawn at weeks 1, 15 and 32. Serum samples were analysed for 25(OH)D and parathyroid hormone (PTH). Seventy-eight recruits (7.2 %) suffered a total of 92 stress fractures. Recruits with a baseline serum 25(OH)D concentration below 50 nmol L(-1) had a higher incidence of stress fracture than recruits with 25(OH)D concentration above this threshold (χ(2) (1) = 3.564, p = 0.042; odds ratio 1.6 (95 % confidence interval (CI) 1.0-2.6)). Baseline serum 25(OH)D varied from 47.0 ± 23.7 nmol L(-1) in February, to 97.3 ± 24.6 nmol L(-1) in July (overall mean 69.2 ± 29.2 nmol L(-1), n = 1016). There were weak inverse correlations between serum 25(OH)D and PTH concentrations at week 15 (r = -0.209, p < 0.001) and week 32 (r = -0.214, p < 0.001), but not at baseline. Baseline serum 25(OH)D concentration below 50 nmol L(-1) was associated with an increased risk of stress fracture. Further

  7. [Percutaneous surgery for plantar fasciitis due to a calcaneal spur].

    PubMed

    Apóstol-González, Saúl; Herrera, Jesús

    2009-01-01

    Determine the efficacy of percutaneous surgical treatment for talalgia due to a calcaneal spur. This is an observational, descriptive, clinical series analyzing the outcomes of 10 patients with a diagnosis of talalgia due to plantar fasciitis with a calcaneal spur treated with percutaneous foot surgery. The end result was assessed with a visual analog scale (VAS) to measure pain, the patients' opinion and their return to activities of daily living. Central tendency and scatter measurements were calculated. The inferential analysis was done with the non-parametric chi square (chi2) test. Most patients were females (90%) and mean age was 40.5 years. Follow-up was 12 months. One patient had bleeding of the approached area. Pain was reduced from 8 to 1.5 in the VAS. Nine patients returned to their activities. Two patients had occasional mild pain upon prolonged bipedestation. Ninety percent of results were satisfactory. Percutaneous foot surgery in talalgias caused by plantar fasciitis due to a calcaneal spur is a simple and effective method. It reduces the operative time and allows for an early return of patients to their activities of daily living.

  8. Correlation of stress-wave-emission characteristics with fracture aluminum alloys

    NASA Technical Reports Server (NTRS)

    Hartbower, C. E.; Reuter, W. G.; Morais, C. F.; Crimmins, P. P.

    1972-01-01

    A study to correlate stress wave emission characteristics with fracture in welded and unwelded aluminum alloys tested at room and cryogenic temperature is reported. The stress wave emission characteristics investigated were those which serve to presage crack instability; viz., a marked increase in:(1) signal amplitude; (2) signal repetition rate; and (3) the slope of cumulative count plotted versus load. The alloys were 7075-T73, 2219-T87 and 2014-T651, welded with MIG and TIG using 2319 and 4043 filler wire. The testing was done with both unnotched and part-through-crack (PTC) tension specimens and with 18-in.-dia subscale pressure vessels. In the latter testing, a real time, acoustic emission, triangulation system was used to locate the source of each stress wave emission. With such a system, multiple emissions from a given location were correlated with defects found by conventional nondestructive inspection.

  9. Management of ischiopubic stress fracture in patients with anorexia nervosa and excessive compulsive exercising

    PubMed Central

    El Ghoch, Marwan; Bazzani, Paola; Dalle Grave, Riccardo

    2014-01-01

    This case report describes a 28-year-old non-athlete female patient with anorexia nervosa who was diagnosed with an ischiopubic ramus stress fracture and treated successfully as an inpatient with a cognitive behaviour-based therapy. The patient's clinical picture, diagnosis and treatment are described, and a brief review of the relevant literature is included. The importance of this case report stems from the rarity of descriptions of this kind of injury in such patients, despite their inherent risk, and the originality of the treatment applied. This, in addition to the usual approach to medical management, exploited specific cognitive and behavioural procedures and strategies to address the patient's excessive compulsive exercising, promoting rest and movement avoidance in order to allow the fracture to heal, while simultaneously addressing the underlying psychopathology. PMID:25301426

  10. Femoral diaphyseal stress fracture as the initial presentation of acute leukaemia in an adolescent.

    PubMed

    Chase, Helen Emily; Pang, Joe Hwong; Sanghrajka, Anish Pradip

    2016-06-28

    A 14-year-old boy was referred to the orthopaedic clinic by his general practitioner, reporting of a 6-week history of left thigh pain. Clinical examination was unremarkable. Radiographs demonstrated a periosteal reaction at the proximal femur. MRI scans demonstrated a stress fracture of the femur, with no associated sinister features and no evidence of a pathological lesion. As the fracture healed and symptoms improved, the patient became unwell with weight loss, lethargy, chest and jaw pain and fevers. After multiple blood tests over a 25-day period, including five full blood counts and two normal blood films, a third blood film finally demonstrated blasts in keeping with acute leukaemia. We discuss a literature review of musculoskeletal manifestations of leukaemia and the often atypical presentations found. 2016 BMJ Publishing Group Ltd.

  11. On the expected relationships among apparent stress, static stress drop, effective shear fracture energy, and efficiency

    Beeler, N.M.; Wong, T.-F.; Hickman, S.H.

    2003-01-01

    We consider expected relationships between apparent stress ??a and static stress drop ????s using a standard energy balance and find ??a = ????s (0.5 - ??), where ?? is stress overshoot. A simple implementation of this balance is to assume overshoot is constant; then apparent stress should vary linearly with stress drop, consistent with spectral theories (Brune, 1970) and dynamic crack models (Madariaga, 1976). Normalizing this expression by the static stress drop defines an efficiency ??sw = ??sa/????s as follows from Savage and Wood (1971). We use this measure of efficiency to analyze data from one of a number of observational studies that find apparent stress to increase with seismic moment, namely earthquakes recorded in the Cajon Pass borehole by Abercrombie (1995). Increases in apparent stress with event size could reflect an increase in seismic efficiency; however, ??sw for the Cajon earthquakes shows no such increase and is approximately constant over the entire moment range. Thus, apparent stress and stress drop co-vary, as expected from the energy balance at constant overshoot. The median value of ??sw for the Cajon earthquakes is four times lower than ??sw for laboratory events. Thus, these Cajon-recorded earthquakes have relatively low and approximately constant efficiency. As the energy balance requires ??sw = 0.5 - ??, overshoot can be estimated directly from the Savage-Wood efficiency; overshoot is positive for Cajon Pass earthquakes. Variations in apparent stress with seismic moment for these earthquakes result primarily from systematic variations in static stress drop with seismic moment and do not require a relative decrease in sliding resistance with increasing event size (dynamic weakening). Based on the comparison of field and lab determinations of the Savage-Wood efficiency, we suggest the criterion ??sw > 0.3 as a test for dynamic weakening in excess of that seen in the lab.

  12. Fabrication and Probabilistic Fracture Strength Prediction of High-Aspect-Ratio Single Crystal Silicon Carbide Microspecimens With Stress Concentration

    NASA Technical Reports Server (NTRS)

    Nemeth, Noel N.; Evans, Laura J.; Jadaan, Osama M.; Sharpe, William N., Jr.; Beheim, Glenn M.; Trapp, Mark A.

    2005-01-01

    Single crystal silicon carbide micro-sized tensile specimens were fabricated with deep reactive ion etching (DRIE) in order to investigate the effect of stress concentration on the room-temperature fracture strength. The fracture strength was defined as the level of stress at the highest stressed location in the structure at the instant of specimen rupture. Specimens with an elliptical hole, a circular hole, and without a hole (and hence with no stress concentration) were made. The average fracture strength of specimens with a higher stress concentration was larger than the average fracture strength of specimens with a lower stress concentration. Average strength of elliptical-hole, circular-hole, and without-hole specimens was 1.53, 1.26, and 0.66 GPa, respectively. Significant scatter in strength was observed with the Weibull modulus ranging between 2 and 6. No fractographic examination was performed but it was assumed that the strength controlling flaws originated from etching grooves along the specimen side-walls. The increase of observed fracture strength with increasing stress concentration was compared to predictions made with the Weibull stress-integral formulation by using the NASA CARES/Life code. In the analysis isotropic material and fracture behavior was assumed - hence it was not a completely rigorous analysis. However, even with these assumptions good correlation was achieved for the circular-hole specimen data when using the specimen data without stress concentration as a baseline. Strength was over predicted for the elliptical-hole specimen data. Significant specimen-to-specimen dimensional variation existed in the elliptical-hole specimens due to variations in the nickel mask used in the etching. To simulate the additional effect of the dimensional variability on the probabilistic strength response for the single crystal specimens the ANSYS Probabilistic Design System (PDS) was used with CARES/Life.

  13. Two-View Gravity Stress Imaging Protocol for Nondisplaced Type II Supination External Rotation Ankle Fractures: Introducing the Gravity Stress Cross-Table Lateral View.

    PubMed

    Boffeli, Troy J; Collier, Rachel C; Gervais, Samuel J

    Assessing ankle stability in nondisplaced Lauge-Hansen supination external rotation type II injuries requires stress imaging. Gravity stress mortise imaging is routinely used as an alternative to manual stress imaging to assess deltoid integrity with the goal of differentiating type II from type IV injuries in cases without a posterior or medial fracture. A type II injury with a nondisplaced fibula fracture is typically treated with cast immobilization, and a type IV injury is considered unstable and often requires operative repair. The present case series (two patients) highlights a standardized 2-view gravity stress imaging protocol and introduces the gravity stress cross-table lateral view. The gravity stress cross-table lateral view provides a more thorough evaluation of the posterior malleolus owing to the slight external rotation and posteriorly directed stress. External rotation also creates less bony overlap between the tibia and fibula, allowing for better visualization of the fibula fracture. Gravity stress imaging confirmed medial-sided injury in both cases, confirming the presence of supination external rotation type IV or bimalleolar equivalent fractures. Open reduction and internal fixation was performed, and both patients achieved radiographic union. No further treatment was required at 21 and 33 months postoperatively. Copyright © 2017 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  14. Do stress fractures induce hypertrophy of the grafted fibula? A report of three cases received free vascularized fibular graft treatment for tibial defects.

    PubMed

    Qi, Yong; Sun, Hong-Tao; Fan, Yue-Guang; Li, Fei-Meng; Lin, Zhou-Sheng

    2016-06-01

    The presence of large segmental defects of the diaphyseal bone is challenging for orthopedic surgeons. Free vascularized fibular grafting (FVFG) is considered to be a reliable reconstructive procedure. Stress fractures are a common complication following this surgery, and hypertrophy is the main physiological change of the grafted fibula. The exact mechanism of hypertrophy is not completely known. To the best of our knowledge, no studies have examined the possible relationship between stress fractures and hypertrophy. We herein report three cases of patients underwent FVFG. Two of them developed stress fractures and significant hypertrophy, while the remaining patient developed neither stress fractures nor significant hypertrophy. This phenomenon indicates that a relationship may exist between stress fractures and hypertrophy of the grafted fibula, specifically, that the presence of a stress fracture may initiate the process of hypertrophy.

  15. The Epidemiology of Stress Fractures in Collegiate Student-Athletes, 2004-2005 Through 2013-2014 Academic Years.

    PubMed

    Rizzone, Katherine H; Ackerman, Kathryn E; Roos, Karen G; Dompier, Thomas P; Kerr, Zachary Y

    2017-10-01

    Stress fractures are injuries caused by cumulative, repetitive stress that leads to abnormal bone remodeling. Specific populations, including female athletes and endurance athletes, are at higher risk than the general athletic population. Whereas more than 460 000 individuals participate in collegiate athletics in the United States, no large study has been conducted to determine the incidence of stress fractures in collegiate athletes.   To assess the incidence of stress fractures in National Collegiate Athletic Association (NCAA) athletes and investigate rates and patterns overall and by sport.   Descriptive epidemiology study.   National Collegiate Athletic Association institutions.   National Collegiate Athletic Association athletes.   Data were analyzed from the NCAA Injury Surveillance Program for the academic years 2004-2005 through 2013-2014. We calculated rates and rate ratios (RRs) with 95% confidence intervals (CIs).   A total of 671 stress fractures were reported over 11 778 145 athlete-exposures (AEs) for an overall injury rate of 5.70 per 100 000 AEs. The sports with the highest rates of stress fractures were women's cross-country ( 28.59/100  000 AEs), women's gymnastics ( 25.58/100  000 AEs), and women's outdoor track ( 22.26/100  000 AEs). Among sex-comparable sports (baseball/softball, basketball, cross-country, ice hockey, lacrosse, soccer, swimming and diving, tennis, indoor track, and outdoor track), stress fracture rates were higher in women (9.13/100 000 AEs) than in men (4.44/100 000 AEs; RR = 2.06; 95% CI = 1.71, 2.47). Overall, stress fracture rates for these NCAA athletes were higher in the preseason (7.30/100 000 AEs) than in the regular season (5.12/100 000 AEs; RR = 1.43; 95% CI = 1.22, 1.67). The metatarsals (n = 254, 37.9%), tibia (n = 147, 21.9%), and lower back/lumbar spine/pelvis (n = 81, 12.1%) were the most common locations of injury. Overall, 21.5% (n = 144) of stress fractures were

  16. Recent developments in analysis of crack propagation and fracture of practical materials. [stress analysis in aircraft structures

    NASA Technical Reports Server (NTRS)

    Hardrath, H. F.; Newman, J. C., Jr.; Elber, W.; Poe, C. C., Jr.

    1978-01-01

    The limitations of linear elastic fracture mechanics in aircraft design and in the study of fatigue crack propagation in aircraft structures are discussed. NASA-Langley research to extend the capabilities of fracture mechanics to predict the maximum load that can be carried by a cracked part and to deal with aircraft design problems are reported. Achievements include: (1) improved stress intensity solutions for laboratory specimens; (2) fracture criterion for practical materials; (3) crack propagation predictions that account for mean stress and high maximum stress effects; (4) crack propagation predictions for variable amplitude loading; and (5) the prediction of crack growth and residual stress in built-up structural assemblies. These capabilities are incorporated into a first generation computerized analysis that allows for damage tolerance and tradeoffs with other disciplines to produce efficient designs that meet current airworthiness requirements.

  17. Femoral neck stress fracture in a female athlete: a case report

    PubMed Central

    Avrahami, Daniel; Pajaczkowski, Jason A.

    2012-01-01

    Objective The purpose of this case report is to describe chiropractic rehabilitation of a master's-level athlete with proximal femoral stress fracture and provide a brief discussion of stress fracture pathology. Clinical Features A 41-year-old female master's-level endurance athlete presented with chronic groin pain later diagnosed and confirmed by magnetic resonance imaging as a stress fracture of the femoral neck. After diagnosis, the patient was referred to a doctor of chiropractic at week 1 of the non–weight-bearing physical rehabilitation process. At that time, the patient presented with sharp and constant groin pain rated 6/10 on a numeric rating scale. Intervention and Outcome This patient avoided weight-bearing activity for 8 weeks while cross-training and was able to return to her sport after this period. The patient was progressed through a series of non–weight-bearing strengthening exercises for the lower extremity. Myofascial release therapy was performed on the gluteal, hip flexor, and groin muscle groups to improve range of motion. Motion palpation testing the lumbar and sacroiliac joints was performed during each session, and manipulative therapy was performed when necessary. The patient was seen once a week for 8 weeks. Reevaluation was performed at week 8; at that time, the patient reported no groin pain (0/10). The patient was discharged from care and referred back to the supervising physician for clearance to return to sporting activities. One month after discharge, she reported that she was pain free and had fully returned to sport activities. Conclusion This case report demonstrates the importance of a through clinical history, physical examination, and magnetic resonance imaging in the accurate diagnosis of a patient with chronic groin pain and that chiropractic care can contribute to rehabilitation programs for these injuries. PMID:23843760

  18. Stress Memory in Fluid-Filled Fractures - Insights From Induced Seismicity

    NASA Astrophysics Data System (ADS)

    Dura-Gomez, I.; Talwani, P.

    2007-05-01

    Detailed studies of reservoir and injection induced seismicity provide an opportunity to study the characteristics of the fractures associated with fluid-induced seismicity. In 1996, we noted that the first three series of earthquakes with M greater or equal than 5.0 in the vicinity of the Koyna reservoir, occurred only when the reservoir levels had exceeded the previous maxima. In subsequent years, three more similar episodes were noted in the vicinity of the Koyna and the nearby Warna reservoir, without a single repetition in the epicentral location. This behavior was similar to Kaiser effect observed in the laboratory. A similar behavior has been observed in many cases of injection induced seismicity. At the Denver arsenal well in the 1960s and the Soultz, France, hot rock site in the 1990s, among others, seismicity only occurred when the differential pressure, (downhole well borehole pressure excess over the ambient natural pressure) reached a threshold value. These threshold values differed for different wells and depths. The seismicity stopped when the differential pressure was lowered below the threshold value. These observations show that the stress memory (associated with Kaiser effect) observed in the laboratory with small samples, is also displayed in nature where the volume of rocks is from hundreds to thousands of cu.km. The fluid-filled seismogenic fractures near the reservoirs and bore wells, associated with fluid-induced seismicity, seems to behave like a finely tuned, sensitive system that "remember" the largest stress perturbation they have been subjected to. Here we present these observations of stress memory in fluid-filled fractures associated with induced seismicity and suggest possible causes.

  19. Permeability, Fracture Clusters, and Stress State:Implications for Mine-based Studies of EcoHydrology

    NASA Astrophysics Data System (ADS)

    Earnest, E. J.; Boutt, D. F.; Murdoch, L.; Hisz, D. B.; Ebenhack, J.; Kieft, T. L.; Onstott, T. C.; Wang, H. F.

    2011-12-01

    Mine-based ecohydrology studies provide unique access to deep flow systems at multiple crustal depths. Mass and energy transfer in such deep flow systems is typically dominated by localized flow through discrete features such as fractures and faults, of which only a small percentage contribute to both local and regional flow systems. Predicting which fractures are contributing to flow and transport in these networks has proven extremely difficult. Researchers working at deeper crustal levels (Barton et al., 1995) have successfully predicted fracture network permeability using relationships between fracture aperture (i.e. transmissivity) and in-situ stress. Observations suggest that compared to porous media, fractured rocks have flow systems that operate across large spatial scales and may contain clusters that are hydraulically isolated. . This point is important as these flow systems can house fluids and microbes in isolated clusters and are minimally impacted by the presence of a mine. One example of this is the the former Homestake gold mine in the northern Black Hills, South Dakota, which is being considered as a location for an underground science laboratory. Mine workings cover several km2 in plan and extend to a depth 2.4 km. The area is dominantly Proterozoic metamorphic rocks, forming regional-scale folds with plunge axes oriented ~40o to the SSE. Prior analysis of the hydrogeology of the area indicates that permeability is strongly dependent on effective stress; an increase in permeability with decreasing depth appears to be an important factor controlling the development of a shallow ground water flow systems. In this contribution we examine a set of factors contributing to permeability distribution at the site with a specific focus on: 1) refining permeability-depth models for fractured rock to include the influence of both normal and shear fracture deformation on permeability-depth trends, 2) promote the development and testing of a stress

  20. CT findings of a unicameral calcaneal bone cyst containing a fluid-fluid level.

    PubMed

    Gallagher, Thomas A; Lim-Dunham, Jennifer E; Vade, Aruna

    2007-03-01

    Calcaneal unicameral bone cysts often contain fluid, but rarely contain fluid-fluid levels. We present a case focusing on the CT findings of a large calcaneal bone cyst with a fluid-fluid level and a review of the literature.

  1. Preoperative planning and intraoperative technique for accurate realignment of the Dwyer calcaneal osteotomy.

    PubMed

    Lamm, Bradley M; Gesheff, Martin G; Salton, Heather L; Dupuis, Travis W; Zeni, Ferras

    2012-01-01

    The Dwyer calcaneal osteotomy is an effective procedure for the correction of calcaneal varus deformity. However, no intraoperative method has been described to determine the amount of bone resection. We describe a simple intraoperative method for assuring accurate bone resection and measure the realignment effects of the Dwyer calcaneal osteotomy. We also review radiographic outcomes associated with 20 Dwyer calcaneal osteotomies (in 17 patients) using the intraoperative realignment technique described in this report. Preoperative and postoperative radiographs at a mean of 2.5 (range 1.5 to 5) years taken after Dwyer osteotomy were measured and compared, which revealed a mean reduction in calcaneal varus of 18° (range 2° to 36°) (p < .001), a mean decrease in the calcaneal inclination angle of 5° (range -40° to 7°) (p < .05), a mean decrease in medial calcaneal translation of 10 (range 0 to 18) mm (p < .001) relative to the tibia, and a mean dorsal translation of 2 (range 0 to 7) mm (p = .002). In an effort to attempt to structurally realign the calcaneus to a more rectus alignment, by means of Dwyer osteotomy, we recommend the use of the intraoperative bone wedge resection technique described in this report. Our experience with the patients described in this report demonstrates the usefulness of the intraoperative method that we describe in order to accurately restore the axial tibial and calcaneal relationship. Copyright © 2012 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  2. Serum 25-Hydroxyvitamin D Levels and Stress Fractures in Military Personnel: A Systematic Review and Meta-analysis.

    PubMed

    Dao, Dyda; Sodhi, Sukhmani; Tabasinejad, Rasam; Peterson, Devin; Ayeni, Olufemi R; Bhandari, Mohit; Farrokhyar, Forough

    2015-08-01

    Low serum 25-hydroxyvitamin D (25(OH)D) levels have been associated with stress fractures in various physically active populations such as the military. To examine the association between serum 25(OH)D levels and stress fractures in the military. Systematic review and meta-analysis. Relevant studies were identified through searching multiple databases and manually screening reference lists. Two reviewers independently selected the included studies by applying the eligibility criteria to the title, abstract, and/or full text of the articles yielded in the search. Two reviewers also independently conducted the methodological quality assessment and data extraction. A random-effects model was used to calculate the mean difference (MD) with 95% CI in serum 25(OH)D levels between stress fracture cases and controls. Nine observational studies on lower extremity stress fractures were eligible, and 1 was excluded due to inadequate data. A total of 2634 military personnel (age, 18-30 years; 44% male) with 761 cases (16% male) and 1873 controls (61% male) from 8 studies were included in the analysis. Three of the 8 studies measured serum 25(OH)D levels at the time of stress fracture diagnosis, and the 5 remaining studies measured serum 25(OH)D levels at the time of entry into basic training. The mean serum 25(OH)D level was lower in stress fracture cases than in controls at the time of entry into basic training (MD, -2.63 ng/mL; 95% CI, -5.80 to 0.54; P = .10; I(2) = 65%) and at the time of stress fracture diagnosis (MD, -2.26 ng/mL; 95% CI, -3.89 to -0.63; P = .007; I(2) = 42%). Despite the inherent limitations of the included studies, the study results suggest some association between low serum 25(OH)D levels and lower extremity stress fractures in military personnel. Given the rigorous training of military personnel, implementing strategies to ensure sufficient 25(OH)D levels may be beneficial for reducing the risk of stress fractures. © 2014 The Author(s).

  3. Induced stress changes and associated fracture development as a result of deglaciation on the Zugspitzplatt, SE Germany

    NASA Astrophysics Data System (ADS)

    Leith, Kerry; Kupp, Jan; Geisenhof, Benedikt; Krautblatter, Michael

    2015-04-01

    Bedrock stresses in alpine regions result from the combined effects of exhumation, tectonics, topography, inelastic strain (e.g. fault displacement and fracture formation), and external loading. Gravitational loading by glacial ice can significantly affect near-surface stress magnitudes, although the nature of this effect and it's impact on stress distributions and bedrock fracturing is strongly dependent on the stress history of the bedrock landscape. We assess the effects of recent (post-Little Ice Age , ~1850 AD) and future deglaciation on bedrock stresses in the region of the Zugspitzplatt, a glaciated plateau surrounded by 1500 m high bedrock walls in SE Germany. We address this by undertaking a 2-D elasto-plastic finite element method analysis of stress changes and fracture propagation due to repeated glacial - interglacial cycles. Our model is initialised with upper crustal stresses in equilibrium with bedrock strength and regional tectonics, and we then simulate two cycles of major Pleistocene glaciation and deglaciation in order to dissipate stress concentrations and incorporate path-dependent effects of glacial loading on the landscape. We then simulate a final glacial cycle, and remove 1 m of bedrock to approximate glacial erosion across the topography. Finally, ice levels are reduced in accordance with known late-glacial and recent ice retreat, allowing us to compare relative stress changes and predicted patterns of fracture propagation to observed fracture distributions on the Zugspitzplatt. Model results compare favourably to observed fracture patterns, and indicate the plateau is likely to be undergoing N-S extension as a result of deglaciation, with a strong reduction of horizontal stress magnitudes beneath the present-day Schneeferner glacier. As each glacial cycle has a similar effect on the plateau, it is likely that surficial stresses are slightly tensile, and each cycle of deglaciation produces additional sub-vertical tensile fractures, which

  4. Females have a greater incidence of stress fractures than males in both military and athletic populations: a systemic review.

    PubMed

    Wentz, Laurel; Liu, Pei-Yang; Haymes, Emily; Ilich, Jasminka Z

    2011-04-01

    The purpose of this study was to review incidence of stress fractures in military and athlete populations and identify factors explaining causes and differences in the incidence among genders. Searches were conducted using several major databases. The studies were included if they were original studies including both male and female subjects and their aim was to identify incidence rates and risk factors contributing to the development of stress fractures. Of several thousand studies, 11 focusing on military populations and 10 on athletes are discussed. In both populations, females had higher incidence of stress fractures, with incidence of approximately 3% and approximately 9.2% for males and females, respectively, in military populations and approximately 6.5% and approximately 9.7%, respectively, in athletes. Factors possibly explaining why females are more susceptible to stress fractures include bone anatomy, lower aerobic capacity, smaller muscle, and poor diet. However, both female recruits and athletes with normal weight and bone health are less likely to develop stress fractures, showing that gender is less important than the overall physical shape/condition.

  5. Cyclic Strain Resistance, Stress Response, Fatigue Life, and Fracture Behavior of High Strength Low Alloy Steel 300 M

    NASA Astrophysics Data System (ADS)

    Manigandan, K.; Srivatsan, T. S.; Tammana, Deepthi; Poorgangi, Behrang; Vasudevan, Vijay K.

    2014-05-01

    The focus of this technical manuscript is a record of the specific role of microstructure and test specimen orientation on cyclic stress response, cyclic strain resistance, and cyclic stress versus strain response, deformation and fracture behavior of alloy steel 300 M. The cyclic strain amplitude-controlled fatigue properties of this ultra-high strength alloy steel revealed a linear trend for the variation of log elastic strain amplitude with log reversals-to-failure, and log plastic strain amplitude with log reversals-to-failure for both longitudinal and transverse orientations. Test specimens of the longitudinal orientation showed only a marginal improvement over the transverse orientation at equivalent values of plastic strain amplitude. Cyclic stress response revealed a combination of initial hardening for the first few cycles followed by gradual softening for a large portion of fatigue life before culminating in rapid softening prior to catastrophic failure by fracture. Fracture characteristics of test specimens of this alloy steel were different at both the macroscopic and fine microscopic levels over the entire range of cyclic strain amplitudes examined. Both macroscopic and fine microscopic observations revealed fracture to be a combination of both brittle and ductile mechanisms. The underlying mechanisms governing stress response, deformation characteristics, fatigue life, and final fracture behavior are presented and discussed in light of the competing and mutually interactive influences of test specimen orientation, intrinsic microstructural effects, deformation characteristics of the microstructural constituents, cyclic strain amplitude, and response stress.

  6. HSTRESS: A computer program to calculate the height of a hydraulic fracture in a multi-layered stress medium

    SciT

    Warpinski, N.R.

    A computer code for calculating hydraulic fracture height and width in a stressed-layer medium has been modified for easy use on a personal computer. HSTRESS allows for up to 51 layers having different thicknesses, stresses and fracture toughnesses. The code can calculate fracture height versus pressure or pressure versus fracture height, depending on the design model in which the data will be used. At any pressure/height, a width profile is calculated and an equivalent width factor and flow resistance factor are determined. This program is written in FORTRAN. Graphics use PLOT88 software by Plotworks, Inc., but the graphics software mustmore » be obtained by the user because of licensing restrictions. A version without graphics can also be run. This code is available through the National Energy Software Center (NESC), operated by Argonne National Laboratory. 14 refs., 21 figs.« less

  7. Fracture mechanics correlation of boron/aluminum coupons containing stress risers

    NASA Technical Reports Server (NTRS)

    Adsit, N. R.; Waszczak, J. P.

    1975-01-01

    The mechanical behavior of boron/aluminum near stress risers has been studied and reported. This effort was directed toward defining the tensile behavior of both unidirectional and (0/ plus or minus 45) boron/aluminum using linear elastic fracture mechanics (LEFM). The material used was 5.6-mil boron in 6061 aluminum, consolidated using conventional diffusion bonding techniques. Mechanical properties are reported for both unidirectional and (0/ plus or minus 45) boron/aluminum, which serve as control data for the fracture mechanics predictions. Three different flawed specimen types were studied. In each case the series of specimens remained geometrically similar to eliminate variations in finite size correction factors. The fracture data from these tests were reduced using two techniques. They both used conventional LEFM methods, but the existence of a characteristic flaw was assumed in one case and not the other. Both the data and the physical behavior of the specimens support the characteristic flaw hypothesis. Cracks were observed growing slowly in the (0/ plus or minus 45) laminates, until a critical crack length was reached at which time catastrophic failure occurred.

  8. Stress transfer and matrix-cohesive fracture mechanism in microfibrillated cellulose-gelatin nanocomposite films.

    PubMed

    Quero, Franck; Padilla, Cristina; Campos, Vanessa; Luengo, Jorge; Caballero, Leonardo; Melo, Francisco; Li, Qiang; Eichhorn, Stephen J; Enrione, Javier

    2018-09-01

    Microfibrillated cellulose (MFC) obtained from eucalyptus was embedded in gelatin from two sources; namely bovine and salmon gelatin. Raman spectroscopy revealed that stress is transferred more efficiently from bovine gelatin to the MFC when compared to salmon gelatin. Young's modulus, tensile strength, strain at failure and work of fracture of the nanocomposite films were improved by ∼67, 131, 43 y 243% respectively when using salmon gelatin as matrix material instead of bovine gelatin. Imaging of the tensile fracture surface of the MFC-gelatin nanocomposites revealed that crack formation occurs predominantly within bovine and salmon gelatin matrices rather than within the MFC or at the MFC/gelatin interface. This suggests that the mechanical failure mechanism in these nanocomposite materials is predominantly governed by a matrix-cohesive fracture mechanism. Both strength and flexibility are desirable properties for composite coatings made from gelatin-based materials, and so the findings of this study could assist in their utilization in the food and pharmaceutical industry. Copyright © 2018 Elsevier Ltd. All rights reserved.

  9. Maxillofacial fractures and craniocerebral injuries - stress propagation from face to neurocranium in a finite element analysis.

    PubMed

    Huempfner-Hierl, Heike; Schaller, Andreas; Hierl, Thomas

    2015-04-21

    Severe facial trauma is often associated with intracerebral injuries. So it seemed to be of interest to study stress propagation from face to neurocranium after a fistlike impact on the facial skull in a finite element analysis. A finite element model of the human skull without mandible consisting of nearly 740,000 tetrahedrons was built. Fistlike impacts on the infraorbital rim, the nasoorbitoethmoid region, and the supraorbital arch were simulated and stress propagations were depicted in a time-dependent display. Finite element simulation revealed von Mises stresses beyond the yield criterion of facial bone at the site of impacts and propagation of stresses in considerable amount towards skull base in the scenario of the fistlike impact on the infraorbital rim and on the nasoorbitoethmoid region. When impact was given on the supraorbital arch stresses seemed to be absorbed. As patients presenting with facial fractures have a risk for craniocerebral injuries attention should be paid to this and the indication for a CT-scan should be put widely. Efforts have to be made to generate more precise finite element models for a better comprehension of craniofacial and brain injury.

  10. Weightbearing vs Gravity Stress Radiographs for Stability Evaluation of Supination-External Rotation Fractures of the Ankle.

    PubMed

    Seidel, Angela; Krause, Fabian; Weber, Martin

    2017-07-01

    Isolated lateral malleolar fractures may result from a supination-external rotation (SER) injury of the ankle. Stable fractures maintain tibiotalar congruence due to competent medial restraints and can be treated nonoperatively with excellent functional results and long-term prognosis. Stability might be assessed with either stress radiographs or weightbearing radiographs. A consecutive series of patients with closed SER fractures (presumed AO 44-B1) were prospectively enrolled from 2008 to 2015. Patients with clearly unstable fractures (medial clear space more than 7 mm) on the initial nonweightbearing radiograph were excluded and operated on. All other patients were examined with a gravity stress and a weightbearing anteroposterior radiograph. Borderline instability of the fracture was assumed when the medial clear space was 4 to 7 mm. Those were treated nonoperatively. Of 104 patients with isolated lateral malleolar fractures of the SER type, 14 patients were treated operatively because of clear instability (displacement) on the initial radiographs. Of the nonoperative patients, 44 patients demonstrated borderline instability on the gravity stress but stability on the weightbearing radiograph ("gravity borderline"); the remaining 46 were stable in both tests ("gravity stable"). At an average follow-up of 23 months, no significant differences were seen in the American Orthopaedic Foot & Ankle Society hindfoot score (92 points gravity-borderline group vs 93 points gravity-unstable group), the Foot Functional Index score (11 vs 10 points), the Short Form 36 (SF-36) physical component (86 vs 85 points), and SF-36 mental component (84 vs 81 points). Radiographically, all fractures had healed with anatomic congruity of the ankle. Weightbearing radiographs provided a reliable basis to decide about stability and nonoperative treatment in isolated lateral malleolar fractures of the SER type with excellent clinical and radiographic outcome at short-term follow-up. Gravity

  11. Nonlinear Fluid Migration Patterns in Fractured Reservoirs due to Stress-Pressure Coupling induced Changes in Reservoir Permeabilities

    NASA Astrophysics Data System (ADS)

    Annewandter, R.; Geiger, S.; Main, I. G.

    2011-12-01

    Sustainable storage of carbon dioxide (CO2) requires a thorough understanding of injection induced pressure build-up and its effects on the storage formation's integrity, since it determines the cap rock's sealing properties as well as the total storable amount of carbon dioxide. Fractures are abundant in the subsurface and difficult to detect due to their subseismic characteristic. If present in the cap during injection, they can be primary pathways for CO2 leakage. The North Sea is considered as Europe's most important carbon dioxide storage area. However, almost all of the potential storage formations have been exposed to post-glacial lithospheric flexure, possibly causing the generation of new fracture networks in the overburden whilst rebounding. Drawing upon, fast carbon dioxide uprise can be facilitated due to opening of fractures caused by changes in the stress field over time. The overall effective permeability, and hence possible leakage rates, of a fractured storage formation is highly sensitive to the fracture aperture which itself depends on the far field and in situ stress field. For this reason, our in-house general purpose reservoir simulator Complex System Modeling Platform (CSMP++) has been expanded, which is particularly designed to simulate multiphase flow on fractured porous media. It combines finite element (FE) and finite volume (FV) methods on mixed-dimensional hybrid-element meshes. The unstructured FE-FV based scheme allows us to model complex geological structures, such as fractures, at great detail. The simulator uses a compositional model for NaCl-H2O-CO2-systems for compressible fluids for computing thermophysical properties as a function of formation pressure and temperature. A fixed stress-split sequential procedure is being used to calculate coupled fluid flow and geomechanics. Numerical proof of concept studies will be presented showing the impact of fracture opening and closure on fluid migration patterns due to coupled stress

  12. Finite Element Analysis of Foot and Ankle Impact Injury: Risk Evaluation of Calcaneus and Talus Fracture.

    PubMed

    Wong, Duo Wai-Chi; Niu, Wenxin; Wang, Yan; Zhang, Ming

    2016-01-01

    Foot and ankle impact injury is common in geriatric trauma and often leads to fracture of rearfoot, including calcaneus and talus. The objective of this study was to assess the influence of foot impact on the risk of calcaneus and talus fracture via finite element analysis. A three-dimensional finite element model of foot and ankle was constructed based on magnetic resonance images of a female aged 28. The foot sustained a 7-kg passive impact through a foot plate. The simulated impact velocities were from 2.0 to 7.0 m/s with 1.0 m/s interval. At 5.0 m/s impact velocity, the maximum von Mises stress of the trabecular calcaneus and talus were 3.21MPa and 2.41MPa respectively, while that of the Tresca stress were 3.46MPa and 2.55MPa. About 94% and 84% of the trabecular calcaneus and talus exceeded the shear yielding stress, while 21.7% and 18.3% yielded the compressive stress. The peak stresses were distributed around the talocalcaneal articulation and the calcaneal tuberosity inferiorly, which corresponded to the common fracture sites. The prediction in this study showed that axial compressive impact at 5.0 m/s could produce considerable yielding of trabecular bone in both calcaneus and talus, dominantly by shear and compounded with compression that predispose the rearfoot in the risk of fracture. This study suggested the injury pattern and fracture mode of high energy trauma that provides insights in injury prevention and fracture management.

  13. kISMET: Stress analysis and intermediate-scale hydraulic fracturing at the Sanford Underground Research Facility

    NASA Astrophysics Data System (ADS)

    Dobson, P. F.; Oldenburg, C. M.; Wu, Y.; Cook, P. J.; Kneafsey, T. J.; Nakagawa, S.; Ulrich, C.; Siler, D. L.; Guglielmi, Y.; Ajo Franklin, J. B.; Rutqvist, J.; Daley, T. M.; Birkholzer, J. T.; Wang, H. F.; Lord, N.; Haimson, B. C.; Sone, H.; Vigilante, P.; Roggenthen, W.; Doe, T.; Lee, M.; Ingraham, M. D.; Huang, H.; Mattson, E.; Johnson, T. C.; Zhou, J.; Zoback, M. D.; Morris, J.; White, J. A.; Johnson, P. A.; Coblentz, D. D.; Heise, J.

    2017-12-01

    In 2015, we established a field test facility at the Sanford Underground Research Facility (SURF), and in 2016 we carried out in situ hydraulic fracturing experiments to characterize the stress field, understand the effects of crystalline rock fabric on fracturing, and gain experience in monitoring using geophysical methods. The kISMET (permeability (k) and Induced Seismicity Management for Energy Technologies) project test site was established in the West Access Drift at the 4850 ft level, 1478 m below ground in phyllite of the Precambrian Poorman Formation. The kISMET team drilled and cored five near-vertical boreholes in a line on 3 m spacing, deviating the two outermost boreholes slightly to create a five-spot pattern around the test borehole centered in the test volume 40 m below the drift invert (floor) at a total depth of 1518 m. Laboratory measurements of core from the center test borehole showed P-wave velocity heterogeneity along each core indicating strong, fine-scale ( 1 cm or smaller) changes in the mechanical properties of the rock. Tensile strength ranges between 3‒7.5 MPa and 5‒12 MPa. Pre-fracturing numerical simulations with a discrete element code were carried out to predict fracture size and magnitude of microseismicity. Field measurements of the stress field were made using hydraulic fracturing, which produced remarkably uniformly oriented fractures suggesting rock fabric did not play a significant role in controlling fracture orientation. Electrical resistivity tomography (ERT) and continuous active seismic source monitoring (CASSM) were deployed in the four monitoring boreholes, and passive seismic accelerometer-based measurements in the West Access Drift were carried out during the generation of a larger fracture (so-called stimulation test). ERT was not able to detect the fracture created, nor did the accelerometers in the drift, but microseismicity was detected for the first (deepest) hydraulic-fracturing stress measurement. Analytical

  14. Evolution and Allometry of Calcaneal Elongation in Living and Extinct Primates

    PubMed Central

    Boyer, Doug M.; Seiffert, Erik R.; Gladman, Justin T.; Bloch, Jonathan I.

    2013-01-01

    Specialized acrobatic leaping has been recognized as a key adaptive trait tied to the origin and subsequent radiation of euprimates based on its observed frequency in extant primates and inferred frequency in extinct early euprimates. Hypothesized skeletal correlates include elongated tarsal elements, which would be expected to aid leaping by allowing for increased rates and durations of propulsive acceleration at takeoff. Alternatively, authors of a recent study argued that pronounced distal calcaneal elongation of euprimates (compared to other mammalian taxa) was related primarily to specialized pedal grasping. Testing for correlations between calcaneal elongation and leaping versus grasping is complicated by body size differences and associated allometric affects. We re-assess allometric constraints on, and the functional significance of, calcaneal elongation using phylogenetic comparative methods, and present an evolutionary hypothesis for the evolution of calcaneal elongation in primates using a Bayesian approach to ancestral state reconstruction (ASR). Results show that among all primates, logged ratios of distal calcaneal length to total calcaneal length are inversely correlated with logged body mass proxies derived from the area of the calcaneal facet for the cuboid. Results from phylogenetic ANOVA on residuals from this allometric line suggest that deviations are explained by degree of leaping specialization in prosimians, but not anthropoids. Results from ASR suggest that non-allometric increases in calcaneal elongation began in the primate stem lineage and continued independently in haplorhines and strepsirrhines. Anthropoid and lorisid lineages show stasis and decreasing elongation, respectively. Initial increases in calcaneal elongation in primate evolution may be related to either development of hallucal-grasping or a combination of grasping and more specialized leaping behaviors. As has been previously suggested, subsequent increases in calcaneal

  15. Return to sports after stress fractures of the tibial diaphysis: a systematic review.

    PubMed

    Robertson, G A J; Wood, A M

    2015-06-01

    This review aims to provide information on the time taken to resume sport following tibial diaphyseal stress fractures (TDSFs). A systematic search of Medline, EMBASE, CINHAL, Cochrane, Web of Science, PEDro, Sports Discus, Scopus and Google Scholar was performed using the keywords 'tibial', 'tibia', 'stress', 'fractures', 'athletes', 'sports', 'non-operative', 'conservative', 'operative' and 'return to sport'. Twenty-seven studies were included: 16 reported specifically on anterior TDSFs and 5 on posterior TDSFs. The general principles were to primarily attempt non-operative management for all TDSFs and to consider operative intervention for anterior TDSFs that remained symptomatic after 3-6 months. Anterior TDSFs showed a prolonged return to sport. The best time to return to sport and the optimal management modalities for TDSFs remain undefined. Management of TDSFs should include a full assessment of training methods, equipment and diet to modify pre-disposing factors. Future prospective studies should aim to establish the optimal treatment modalities for TDSFs. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  16. Effectiveness of various isometric exercises at improving bone strength in cortical regions prone to distal tibial stress fractures.

    PubMed

    Florio, C S

    2018-06-01

    A computational model was used to compare the local bone strengthening effectiveness of various isometric exercises that may reduce the likelihood of distal tibial stress fractures. The developed model predicts local endosteal and periosteal cortical accretion and resorption based on relative local and global measures of the tibial stress state and its surface variation. Using a multisegment 3-dimensional leg model, tibia shape adaptations due to 33 combinations of hip, knee, and ankle joint angles and the direction of a single or sequential series of generated isometric resultant forces were predicted. The maximum stress at a common fracture-prone region in each optimized geometry was compared under likely stress fracture-inducing midstance jogging conditions. No direct correlations were found between stress reductions over an initially uniform circular hollow cylindrical geometry under these critical design conditions and the exercise-based sets of active muscles, joint angles, or individual muscle force and local stress magnitudes. Additionally, typically favorable increases in cross-sectional geometric measures did not guarantee stress decreases at these locations. Instead, tibial stress distributions under the exercise conditions best predicted strengthening ability. Exercises producing larger anterior distal stresses created optimized tibia shapes that better resisted the high midstance jogging bending stresses. Bent leg configurations generating anteriorly directed or inferiorly directed resultant forces created favorable adaptations. None of the studied loads produced by a straight leg was significantly advantageous. These predictions and the insight gained can provide preliminary guidance in the screening and development of targeted bone strengthening techniques for those susceptible to distal tibial stress fractures. Copyright © 2018 John Wiley & Sons, Ltd.

  17. Nutritional factors that influence change in bone density and stress fracture risk among young female cross-country runners.

    PubMed

    Nieves, Jeri W; Melsop, Kathryn; Curtis, Meredith; Kelsey, Jennifer L; Bachrach, Laura K; Greendale, Gail; Sowers, Mary Fran; Sainani, Kristin L

    2010-08-01

    To identify nutrients, foods, and dietary patterns associated with stress fracture risk and changes in bone density among young female distance runners. Two-year, prospective cohort study. Observational data were collected in the course of a multicenter randomized trial of the effect of oral contraceptives on bone health. One hundred and twenty-five female competitive distance runners ages 18-26 years. Dietary variables were assessed with a food frequency questionnaire. Bone mineral density and content (BMD/BMC) of the spine, hip, and total body were measured annually by dual x-ray absorptiometry (DEXA). Stress fractures were recorded on monthly calendars, and had to be confirmed by radiograph, bone scan, or magnetic resonance imaging. Seventeen participants had at least one stress fracture during follow-up. Higher intakes of calcium, skim milk, and dairy products were associated with lower rates of stress fracture. Each additional cup of skim milk consumed per day was associated with a 62% reduction in stress fracture incidence (P < .05); and a dietary pattern of high dairy and low fat intake was associated with a 68% reduction (P < .05). Higher intakes of skim milk, dairy foods, calcium, animal protein, and potassium were associated with significant (P < .05) gains in whole-body BMD and BMC. Higher intakes of calcium, vitamin D, skim milk, dairy foods, potassium, and a dietary pattern of high dairy and low fat were associated with significant gains in hip BMD. In young female runners, low-fat dairy products and the major nutrients in milk (calcium, vitamin D, and protein) were associated with greater bone gains and a lower stress fracture rate. Potassium intake was also associated with greater gains in hip and whole-body BMD. Copyright © 2010 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

  18. Peri-anterior cruciate ligament reconstruction femur fracture: a biomechanical analysis of the femoral tunnel as a stress riser.

    PubMed

    Han, Yung; Sardar, Zeeshan; McGrail, Scott; Steffen, Thomas; Martineau, Paul A

    2011-12-01

    Sixteen case reports of distal femur fractures as post-operative complications after anterior cruciate ligament (ACL) reconstruction have been described in the literature. The femoral tunnel has been suggested as a potential stress riser for fracture formation. Additionally, double bundle ACL reconstructions may compound this risk. This is the first biomechanical study to examine the significance of a stress riser effect of the femoral tunnel(s) after ACL reconstruction. The hypotheses tested in this study are that the femoral tunnel acts as a stress riser for fracture and that this effect increases with the size of the tunnel (8 mm vs. 10 mm) and with the number of tunnels (1 vs. 2). Femoral tunnels simulating single bundle (SB) hamstring graft (8 mm), bone-patellar tendon-bone graft (10 mm), and double bundle (DB) ACL reconstruction (7, 6 mm) were drilled in fourth-generation saw bones. These three experimental groups and a control group consisting of native saw bones without tunnels were loaded to failure. All fractures occurred through the tunnels in the DB group, whereas fractures did not consistently occur through the tunnels in the SB groups. The mean fracture load was 6,145N ± 471N in the native group, 5,691N ± 198N in the 8 mm SB group, 5,702N ± 282N in the 10 mm SB group, and 4,744N ± 418N in the DB group. The mean fracture load for the DB group was significantly lower when compared to the native, 8 mm SB, and 10 mm SB groups independently (P value = 0.0016, 0.0060, and 0.0038, respectively). The mean fracture loads for neither SB groups were not significantly different from the native group. An anatomically placed femoral tunnel in single bundle ACL reconstruction in our experimental model was not a significant stress riser to fracture, whereas the two femoral tunnels in double bundle ACL reconstruction significantly decreased load to failure. The results support the sparsity of reported peri-ACL reconstruction femur fractures in single femoral

  19. Indentation fracture assessment of residual stress in Si{sub 3}N{sub 4}

    SciT

    Wu, K.H.; Liu, K.C.; Sentella, M.

    1996-12-31

    The measurement of residual stress in Si{sub 3}N{sub 4} ceramics was examined using the indentation technique while a bar specimen with a square cross-section was loaded in tension, and an indentation was created by means of a Vicker`s indenter. The stress applied to the specimen ranged from 0 to 98.8 MPa. The crack length and the shape of the crack were measured by both optical and scanning electron microscopes. Results of the tests indicate that the indentation fracture method can be used to accurately determine the residual stress existing in the material as well as to predict the K{sub c}more » value of the material. The indentation load must be higher than a critical value in order to develop a well-defined penny-shaped crack. For the Si{sub 3}N{sub 4} this critical load is approximately 3 kg. A geometric constant is an important factor for the calculation of the residual stress.« less

  20. Discrete element analysis is a valid method for computing joint contact stress in the hip before and after acetabular fracture.

    PubMed

    Townsend, Kevin C; Thomas-Aitken, Holly D; Rudert, M James; Kern, Andrew M; Willey, Michael C; Anderson, Donald D; Goetz, Jessica E

    2018-01-23

    Evaluation of abnormalities in joint contact stress that develop after inaccurate reduction of an acetabular fracture may provide a potential means for predicting the risk of developing post-traumatic osteoarthritis. Discrete element analysis (DEA) is a computational technique for calculating intra-articular contact stress distributions in a fraction of the time required to obtain the same information using the more commonly employed finite element analysis technique. The goal of this work was to validate the accuracy of DEA-computed contact stress against physical measurements of contact stress made in cadaveric hips using Tekscan sensors. Four static loading tests in a variety of poses from heel-strike to toe-off were performed in two different cadaveric hip specimens with the acetabulum intact and again with an intentionally malreduced posterior wall acetabular fracture. DEA-computed contact stress was compared on a point-by-point basis to stress measured from the physical experiments. There was good agreement between computed and measured contact stress over the entire contact area (correlation coefficients ranged from 0.88 to 0.99). DEA-computed peak contact stress was within an average of 0.5 MPa (range 0.2-0.8 MPa) of the Tekscan peak stress for intact hips, and within an average of 0.6 MPa (range 0-1.6 MPa) for fractured cases. DEA-computed contact areas were within an average of 33% of the Tekscan-measured areas (range: 1.4-60%). These results indicate that the DEA methodology is a valid method for accurately estimating contact stress in both intact and fractured hips. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Evolution of stress and strain during 3D folding: application to orthogonal fracture systems in folded turbidites, SW Portugal

    NASA Astrophysics Data System (ADS)

    Reber, J. E.; Schmalholz, S. M.; Lechmann, S. M.

    2009-04-01

    We present field data and numerical modeling results which show the evolution of stress and strain patterns during 3D folding resulting in an orthogonal fracture system. The field area is located near Almograve, SW Portugal. The area is part of the Mira Formation which itself is part of the South Portuguese Zone (SPZ). The structural development of the SPZ is characterized by southwest vergent folding and thrust displacement. The metamorphism in the SPZ increases from diagenetic conditions in the southwest to greenschist-facies conditions to the northeast. The Mira Formation is composed of turbiditic layers of Carboniferous age with low sandstone to shale ratio. The data was gathered at three outcrops which show structures similar to chocolate tablet structures in the folded sandstone layers. Chocolate tablet structures are generated under simultaneous extension in two directions and show two fracture systems of the same age which are perpendicular to each other. However, the Mira Formation is located in a convergent area. Also, the outcrops near Almograve show two fracture systems of different age. The fractures orthogonal to the fold axis and the bedding are crosscut by fractures parallel to the fold axis and orthogonal to the bedding. Our hypothesis for the evolution of the observed fracture systems is as follows; the older fractures which are now orthogonal to the fold axis and to the bedding plane were generated during compression while the layers were still approximately horizontal. They are parallel to σ1(i.e. mode 1 fractures). The second and younger fracture family was generated in a phase where there is local extension in the fold limbs. These fractures are orthogonal to the far-field σ1, parallel to the fold axis and perpendicular to the bedding. The shortening direction is constant during the entire folding process. We test our hypothesis with numerical modeling. We use 2D and 3D finite element codes with a mixed formulation for incompressible flow

  2. Study of fracture and stress-induced morphological instabilities in polymeric materials

    NASA Astrophysics Data System (ADS)

    Sabouri-Ghomi, Mohsen

    We study the phenomena of fracture in polymers at the molecular and continuum level. At a molecular level, we study the failure of polymer/polymer interfaces. Our main focus is on a specific mode of failure known as chain pull-out fracture, which is common to weak adhesive junctions, and polymer blends and mixtures. In the case of the interface between incompatible polymers, reinforcement is achieved by adding a block copolymer to the interface. We introduce a microscopic model based on Brownian dynamics to investigate the effect of the polymerization index N, of the block connector chain, on fracture toughness of such reinforced polymeric junctions. We consider the mushroom regime, where connector chains are grafted with low surface density, for the case of large pulling velocity. We find that for short chains the interface fracture toughness depends linearly on the polymerization index N of the connector chains, while for longer chains the dependence becomes N 3/2. We propose a scaling argument, based on the geometry of the initial configuration, that accounts for both short and long chains and the crossover between them. At the continuum level, we study the pattern selection mechanism of finger-like crack growth phenomena in gradient driven growth problems in general, and the structure of stress-induced morphological instabilities in crazing of polymer glasses in particular. We simulate solidification in a narrow channel through the use of a phase-field model with an adaptive grid. By tuning a dimensionless parameter, the Peclet number, we show a continuous crossover from a free dendrite at high Peclet numbers to anisotropic viscous fingering at low Peclet numbers. At low Peclet numbers we find good agreement between our results, theoretical predictions, and experiment, providing the first quantitative test of solvability theory for anisotropic viscous fingers. For high undercoolings, we find new phenomena, a solid forger which satisfies stability and

  3. Finite element method for analysis of stresses arising in the skull after external loading in cranio-orbital fractures.

    PubMed

    Wanyura, Hubert; Kowalczyk, Piotr; Bossak, Maciej; Samolczyk-Wanyura, Danuta; Stopa, Zygmunt

    2012-01-01

    The craniofacial skeleton remains not fully recognised as far as its mechanical resistance properties are concerned. Heretofore, the only available information on the mechanism of cranial bone fractures came from clinical observations, since the clinical evaluation in a living individual is practically impossible. It seems crucial to implement computer methods of virtual research into clinical practice. Such methods, which have long been used in the technical sciences, may either confirm or disprove previous observations. The aim of the study was to identify the areas of stress concentrations caused by external loads, which can lead to cranio-orbital fractures (COF), by the finite element method (FEM). For numerical analysis, a three-dimensional commercially available geometrical model of the skull was used which was imported into software of FEM. Computations were performed with ANSYS 12.1 Static Structural module. The loads were applied laterally to the frontal squama, the zygomatic process and partly to the upper orbital rim to locate dangerous concentration of stresses potentially resulting in COF. Changes in the area of force application revealed differences in values, quality and the extent of the stress distribution. Depending on the area of force application the following parameters would change: the value and area of stresses characteristic of COF. The distribution of stresses obtained in this study allowed definition of both the locations most vulnerable to fracture and sites from which fractures may originate or propagate.

  4. On the link between stress field and small-scale hydraulic fracture growth in anisotropic rock derived from microseismicity

    NASA Astrophysics Data System (ADS)

    Gischig, Valentin Samuel; Doetsch, Joseph; Maurer, Hansruedi; Krietsch, Hannes; Amann, Florian; Evans, Keith Frederick; Nejati, Morteza; Jalali, Mohammadreza; Valley, Benoît; Obermann, Anne Christine; Wiemer, Stefan; Giardini, Domenico

    2018-01-01

    To characterize the stress field at the Grimsel Test Site (GTS) underground rock laboratory, a series of hydrofracturing and overcoring tests were performed. Hydrofracturing was accompanied by seismic monitoring using a network of highly sensitive piezosensors and accelerometers that were able to record small seismic events associated with metre-sized fractures. Due to potential discrepancies between the hydrofracture orientation and stress field estimates from overcoring, it was essential to obtain high-precision hypocentre locations that reliably illuminate fracture growth. Absolute locations were improved using a transverse isotropic P-wave velocity model and by applying joint hypocentre determination that allowed for the computation of station corrections. We further exploited the high degree of waveform similarity of events by applying cluster analysis and relative relocation. Resulting clouds of absolute and relative located seismicity showed a consistent east-west strike and 70° dip for all hydrofractures. The fracture growth direction from microseismicity is consistent with the principal stress orientations from the overcoring stress tests, provided that an anisotropic elastic model for the rock mass is used in the data inversions. The σ1 stress is significantly larger than the other two principal stresses and has a reasonably well-defined orientation that is subparallel to the fracture plane; σ2 and σ3 are almost equal in magnitude and thus lie on a circle defined by the standard errors of the solutions. The poles of the microseismicity planes also lie on this circle towards the north. Analysis of P-wave polarizations suggested double-couple focal mechanisms with both thrust and normal faulting mechanisms present, whereas strike-slip and thrust mechanisms would be expected from the overcoring-derived stress solution. The reasons for these discrepancies can be explained by pressure leak-off, but possibly may also involve stress field rotation around the

  5. Calcaneal Quantitative Ultrasound Indicates Reduced Bone Status Among Physically Active Adult Forager-Horticulturalists.

    PubMed

    Stieglitz, Jonathan; Madimenos, Felicia; Kaplan, Hillard; Gurven, Michael

    2016-03-01

    Sedentary lifestyle contributes to osteoporosis and fragility fracture risks among modern humans, but whether such risks are prevalent in physically active preindustrial societies with lower life expectancies is unclear. Osteoporosis should be readily observable in preindustrial societies if it was regularly experienced over human history. In this study of 142 older adult Tsimane forager-horticulturalists (mean age ± SD, 62.1 ± 8.6 years; range, 50 to 85 years; 51% female) we used calcaneal quantitative ultrasonography (qUS) to assess bone status, document prevalence of adults with reduced bone status, and identify factors (demographic, anthropometric, immunological, kinesthetic) associated with reduced bone status. Men (23%) are as likely as women (25%) to have reduced bone status, although age-related decline in qUS parameters is attenuated for men. Adiposity and fat-free mass positively co-vary with qUS parameters for women but not men. Leukocyte count is inversely associated with qUS parameters controlling for potential confounders; leukocyte count is positively correlated within adults over time, and adults with persistently low counts have higher adjusted qUS parameters (6% to 8%) than adults with a high count. Reduced bone status characteristic of osteoporosis is common among active Tsimane with minimal exposure to osteoporosis risk factors found in industrialized societies, but with energetic constraints and high pathogen burden. © 2015 American Society for Bone and Mineral Research.

  6. 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

  7. Electromagnetic Monitoring of Hydraulic Fracturing: Relationship to Permeability, Seismicity, and Stress

    NASA Astrophysics Data System (ADS)

    Thiel, Stephan

    2017-09-01

    Hydraulic fracking is a geoengineering application designed to enhance subsurface permeability to maximize fluid and gas flow. Fracking is commonly used in enhanced geothermal systems (EGS), tight shale gas, and coal seam gas (CSG) plays and in CO_2 storage scenarios. Common monitoring methods include microseismics and mapping small earthquakes with great resolution associated with fracture opening at reservoir depth. Recently, electromagnetic (EM) methods have been employed in the field to provide an alternative way of direct detection of fluids as they are pumped in the ground. Surface magnetotelluric (MT) measurements across EGS show subtle yet detectable changes during fracking derived from time-lapse MT deployments. Changes are directional and are predominantly aligned with current stress field, dictating preferential fracture orientation, supported by microseismic monitoring of frack-related earthquakes. Modeling studies prior to the injection are crucial for survey design and feasibility of monitoring fracks. In particular, knowledge of sediment thickness plays a fundamental role in resolving subtle changes. Numerical forward modeling studies clearly favor some form of downhole measurement to enhance sensitivity; however, these have yet to be conclusively demonstrated in the field. Nevertheless, real surface-based monitoring examples do not necessarily replicate the expected magnitude of change derived from forward modeling and are larger than expected in some cases from EGS and CSG systems. It appears the injected fluid volume alone cannot account for the surface change in resistivity, but connectedness of pore space is also significantly enhanced and nonlinear. Recent numerical studies emphasize the importance of percolation threshold of the fracture network on both electrical resistivity and permeability, which may play an important role in accounting for temporal changes in surface EM measurements during hydraulic fracking.

  8. Stress Concentration and Fracture at Inter-variant Boundaries in an Al-Li Alloy

    NASA Technical Reports Server (NTRS)

    Crooks, Roy; Tayon, Wes; Domack, Marcia; Wagner, John; Beaudoin, Armand

    2009-01-01

    Delamination fracture has limited the use of lightweight Al-Li alloys. Studies of secondary, delamination cracks in alloy 2090, L-T fracture toughness samples showed grain boundary failure between variants of the brass texture component. Although the adjacent texture variants, designated B(sub s1) and B(sub s2), behave similarly during rolling, their plastic responses to mechanical tests can be quite different. EBSD data from through-thickness scans were used to generate Taylor factor maps. When a combined boundary normal and shear tensor was used in the calculation, the delaminating grains showed the greatest Taylor Factor differences of any grain pairs. Kernel Average Misorientation (KAM) maps also showed damage accumulation on one side of the interface. Both of these are consistent with poor slip accommodation from a crystallographically softer grain to a harder one. Transmission electron microscopy was used to confirm the EBSD observations and to show the role of slip bands in the development of large, interfacial stress concentrations. A viewgraph presentation accompanies the provided abstract.

  9. Decline in bone mineral density with stress fractures in a woman on depot medroxyprogesterone acetate. A case report.

    PubMed

    Harkins, G J; Davis, G D; Dettori, J; Hibbert, M L; Hoyt, R A

    1999-03-01

    Depot medroxyprogesterone acetate is a popular contraceptive among young, physically active women. However, its administration has been linked to a relative decrease in estrogen levels. Since bone resorption is accelerated during hypoestrogenic states, there has been growing concern about the potential development of osteoporosis and fractures with the use of this contraceptive method. A physically active, 33-year-old woman demonstrated a 12.4% drop in femoral neck bone mineral density (BMD), 6.4% drop in lumbar BMD and 0.8% drop in total BMD with the subsequent development of a tibial stress fracture while on depot medroxyprogesterone acetate. Bone mineralization rapidly improved, and the stress fracture resolved with discontinuation of the medication. The long-term effects of depot medroxyprogesterone acetate on bone mineralization in physically active women should be evaluated more thoroughly.

  10. F-18 fluorodeoxyglucose: Its potential in differentiating between stress fracture and neoplasia

    SciT

    Paul, R.; Ahonen, A.; Virtama, P.

    1989-12-01

    F-18 fluorodeoxyglucose (FDG) accumulates into regions of enhanced glucose uptake and metabolism such as the brain, heart, and malignant tumors. The clinical usefulness of this positron-emitting radiopharmaceutical is illustrated in a case where the clinical picture and CT indicated a malignant bone lesion in the clavicle. Histologically a stress fracture was found secondary to chronic strain on the clavicle. On follow-up the lesion's course was benign. Planar imaging with F-18 FDG was performed twice during follow-up, and on both occasions there was no accumulation of radioactivity over the suspicious area, indicating normal glucose consumption. This case demonstrates the differential diagnosticmore » potential of F-18 FDG and shows that clinically useful information may be obtained without a position emission tomograph.« less

  11. Fundamental differences in axial and appendicular bone density in stress fractured and uninjured Royal Marine recruits--a matched case-control study.

    PubMed

    Davey, Trish; Lanham-New, Susan A; Shaw, Anneliese M; Cobley, Rosalyn; Allsopp, Adrian J; Hajjawi, Mark O R; Arnett, Timothy R; Taylor, Pat; Cooper, Cyrus; Fallowfield, Joanne L

    2015-04-01

    Stress fracture is a common overuse injury within military training, resulting in significant economic losses to the military worldwide. Studies to date have failed to fully identify the bone density and bone structural differences between stress fractured personnel and controls due to inadequate adjustment for key confounding factors; namely age, body size and physical fitness; and poor sample size. The aim of this study was to investigate bone differences between male Royal Marine recruits who suffered a stress fracture during the 32 weeks of training and uninjured control recruits, matched for age, body weight, height and aerobic fitness. A total of 1090 recruits were followed through training and 78 recruits suffered at least one stress fracture. Bone mineral density (BMD) was measured at the lumbar spine (LS), femoral neck (FN) and whole body (WB) using Dual X-ray Absorptiometry in 62 matched pairs; tibial bone parameters were measured using peripheral Quantitative Computer Tomography in 51 matched pairs. Serum C-terminal peptide concentration was measured as a marker of bone resorption at baseline, week-15 and week-32. ANCOVA was used to determine differences between stress fractured recruits and controls. BMD at the LS, WB and FN sites was consistently lower in the stress fracture group (P<0.001). Structural differences between the stress fracture recruits and controls were evident in all slices of the tibia, with the most prominent differences seen at the 38% tibial slice. There was a negative correlation between the bone cross-sectional area and BMD at the 38% tibial slice. There was no difference in serum CTx concentration between stress fracture recruits and matched controls at any stage of training. These results show evidence of fundamental differences in bone mass and structure in stress fracture recruits, and provide useful data on bone risk factor profiles for stress fracture within a healthy military population. Crown Copyright © 2014. Published

  12. Proximal tibial fracture following anterior cruciate ligament reconstruction surgery: a biomechanical analysis of the tibial tunnel as a stress riser.

    PubMed

    Aldebeyan, Wassim; Liddell, Antony; Steffen, Thomas; Beckman, Lorne; Martineau, Paul A

    2017-08-01

    This is the first biomechanical study to examine the potential stress riser effect of the tibial tunnel or tunnels after ACL reconstruction surgery. In keeping with literature, the primary hypothesis tested in this study was that the tibial tunnel acts as a stress riser for fracture propagation. Secondary hypotheses were that the stress riser effect increases with the size of the tunnel (8 vs. 10 mm), the orientation of the tunnel [standard (STT) vs. modified transtibial (MTT)], and with the number of tunnels (1 vs. 2). Tibial tunnels simulating both single bundle hamstring graft (8 mm) and bone-patellar tendon-bone graft (10 mm) either STT or MTT position, as well as tunnels simulating double bundle (DB) ACL reconstruction (7, 6 mm), were drilled in fourth-generation saw bones. These five experimental groups and a control group consisting of native saw bones without tunnels were loaded to failure on a Materials Testing System to simulate tibial plateau fracture. There were no statistically significant differences in peak load to failure between any of the groups, including the control group. The fracture occurred through the tibial tunnel in 100 % of the MTT tunnels (8 and 10 mm) and 80 % of the DB tunnels specimens; however, the fractures never (0 %) occurred through the tibial tunnel of the standard tunnels (8 or 10 mm) (P = 0.032). In the biomechanical model, the tibial tunnel does not appear to be a stress riser for fracture propagation, despite suggestions to the contrary in the literature. Use of a standard, more vertical tunnel decreases the risk of ACL graft compromise in the event of a fracture. This may help to inform surgical decision making on ACL reconstruction technique.

  13. An epiphyseal stress fracture of the foot and shin splints in an anomalous calf muscle in a runner.

    PubMed

    Percy, E C; Gamble, F O

    1980-07-01

    The following case is presented as one of unusual foot and leg lesions encountered in an adolescent long-distance runner. The associated problems of a first metatarsal Salter Harris type II epiphyseal stress fracture, and an accessory calf muscle with "shin splints" in the contralateral leg are discussed. Treatment of these conditions is outlined with eventual return to full function by the athlete.

  14. [Stress fractures of the ribs with acute thoracic pain in a young woman, diagnosed by the bone scan].

    PubMed

    Georgitzikis, Athanasios; Siopi, Dimitra; Doumas, Argyrios; Mitka, Ekaterini; Antoniadis, Antonios

    2010-01-01

    We report the unusual case of a 29 -year old woman with emotional instability who presented with acute onset chest pain after severe chronic cough. The chest X-ray and the serological tests were normal but the CT scanning, and the bone scanning revealed multiple bilateral rib stress fractures, caused by severe coughing and physical activity and worsened by the patient's emotional instability.

  15. Investigating the Influence of Regional Stress on Fault and Fracture Permeability at Pahute Mesa, Nevada National Security Site

    SciT

    Reeves, Donald M.; Smith, Kenneth D.; Parashar, Rishi

    Regional stress may exert considerable control on the permeability and hydraulic function (i.e., barrier to and/or conduit for fluid flow) of faults and fractures at Pahute Mesa, Nevada National Security Site (NNSS). In-situ measurements of the stress field are sparse in this area, and short period earthquake focal mechanisms are used to delineate principal horizontal stress orientations. Stress field inversion solutions to earthquake focal mechanisms indicate that Pahute Mesa is located within a transtensional faulting regime, represented by oblique slip on steeply dipping normal fault structures, with maximum horizontal stress ranging from N29°E to N63°E and average of N42°E. Averagemore » horizontal stress directions are in general agreement with large diameter borehole breakouts from Pahute Mesa analyzed in this study and with stress measurements from other locations on the NNSS.« less

  16. [Effect of axial stress stimulation on tibial and fibular open fractures healing after Taylor space stent fixation].

    PubMed

    Ge, Qihang; Wan, Chunyou; Liu, Yabei; Ji, Xu; Ma, Jihai; Cao, Haikun; Yong, Wei; Liu, Zhao; Zhang, Ningning

    2017-08-01

    To investigate the effect of axial stress stimulation on tibial and fibular open fractures healing after Taylor space stent fixation. The data of 45 cases with tibial and fibular open fractures treated by Taylor space stent fixation who meet the selection criteria between January 2015 and June 2016 were retrospectively analysed. The patients were divided into trial group (23 cases) and control group (22 cases) according to whether the axial stress stimulation was performed after operation. There was no significant difference in gender, age, affected side, cause of injury, type of fracture, and interval time from injury to operation between 2 groups ( P >0.05). The axial stress stimulation was performed in trial group after operation. The axial load sharing ratio was tested, and when the value was less than 10%, the external fixator was removed. The fracture healing time, full weight-bearing time, and external fixator removal time were recorded and compared. After 6 months of external fixator removal, the function of the limb was assessed by Johner-Wruhs criteria for evaluation of final effectiveness of treatment of tibial shaft fractures. There were 2 and 3 cases of needle foreign body reaction in trial group and control group, respectively, and healed after symptomatic anti allergic treatment. All the patients were followed up 8-12 months with an average of 10 months. All the fractures reached clinical healing, no complication such as delayed union, nonunion, or osteomyelitis occurred. The fracture healing time, full weight-bearing time, and external fixator removal time in trial group were significantly shorter than those in control group ( P <0.05). After 6 months of external fixator removal, the function of the limb was excellent in 13 cases, good in 6 cases, fair in 3 cases, and poor in 1 case in trial group, with an excellent and good rate of 82.6%; and was excellent in 5 cases, good in 10 cases, fair in 4 cases, and poor in 3 cases in control group, with an

  17. Ankle joint pressure changes in a pes cavovarus model: supramalleolar valgus osteotomy versus lateralizing calcaneal osteotomy.

    PubMed

    Schmid, Timo; Zurbriggen, Sebastian; Zderic, Ivan; Gueorguiev, Boyko; Weber, Martin; Krause, Fabian G

    2013-09-01

    A fixed cavovarus foot deformity can be associated with anteromedial ankle arthrosis due to elevated medial joint contact stresses. Supramalleolar valgus osteotomies (SMOT) and lateralizing calcaneal osteotomies (LCOT) are commonly used to treat symptoms by redistributing joint contact forces. In a cavovarus model, the effects of SMOT and LCOT on the lateralization of the center of force (COF) and reduction of the peak pressure in the ankle joint were compared. A previously published cavovarus model with fixed hindfoot varus was simulated in 10 cadaver specimens. Closing wedge supramalleolar valgus osteotomies 3 cm above the ankle joint level (6 and 11 degrees) and lateral sliding calcaneal osteotomies (5 and 10 mm displacement) were analyzed at 300 N axial static load (half body weight). The COF migration and peak pressure decrease in the ankle were recorded using high-resolution TekScan pressure sensors. A significant lateral COF shift was observed for each osteotomy: 2.1 mm for the 6 degrees (P = .014) and 2.3 mm for the 11 degrees SMOT (P = .010). The 5 mm LCOT led to a lateral shift of 2.0 mm (P = .042) and the 10 mm LCOT to a shift of 3.0 mm (P = .006). Comparing the different osteotomies among themselves no significant differences were recorded. No significant anteroposterior COF shift was seen. A significant peak pressure reduction was recorded for each osteotomy: The SMOT led to a reduction of 29% (P = .033) for the 6 degrees and 47% (P = .003) for the 11 degrees osteotomy, and the LCOT to a reduction of 41% (P = .003) for the 5 mm and 49% (P = .002) for the 10 mm osteotomy. Similar to the COF lateralization no significant differences between the osteotomies were seen. LCOT and SMOT significantly reduced anteromedial ankle joint contact stresses in this cavovarus model. The unloading effects of both osteotomies were equivalent. More correction did not lead to significantly more lateralization of the COF or more reduction of peak pressure but a trend was

  18. Fractures of the Fifth Metatarsal

    MedlinePlus

    ... overlooked when they occur with an ankle sprain. Jones fracture. Jones fractures occur in a small area of the ... therefore more prone to difficulties in healing. A Jones fracture can be either a stress fracture (a ...

  19. The generalized fracture criteria based on the multi-parameter representation of the crack tip stress field

    NASA Astrophysics Data System (ADS)

    Stepanova, L. V.

    2017-12-01

    The paper is devoted to the multi-parameter asymptotic description of the stress field near the crack tip of a finite crack in an infinite isotropic elastic plane medium subject to 1) tensile stress; 2) in-plane shear; 3) mixed mode loading for a wide range of mode-mixity situations (Mode I and Mode II). The multi-parameter series expansion of stress tensor components containing higher-order terms is obtained. All the coefficients of the multiparameter series expansion of the stress field are given. The main focus is on the discussion of the influence of considering the higher-order terms of the Williams expansion. The analysis of the higher-order terms in the stress field is performed. It is shown that the larger the distance from the crack tip, the more terms it is necessary to keep in the asymptotic series expansion. Therefore, it can be concluded that several more higher-order terms of the Williams expansion should be used for the stress field description when the distance from the crack tip is not small enough. The crack propagation direction angle is calculated. Two fracture criteria, the maximum tangential stress criterion and the strain energy density criterion, are used. The multi-parameter form of the two commonly used fracture criteria is introduced and tested. Thirty and more terms of the Williams series expansion for the near-crack-tip stress field enable the angle to be calculated more precisely.

  20. Analysis of stress-induced oval fractures in a borehole at Deep Sea Drilling Project Site 504, eastern equatorial Pacific

    Morin, R.H.; Flamand, R.

    1999-01-01

    Deep Sea Drilling Project (DSDP) Hole 504B is located in the eastern equatorial Pacific Ocean and extends to a total depth of 2111 m beneath the seafloor (mbsf). Several acoustic televiewer logs have been obtained in this well during successive stages of drilling, and the resulting digital images have revealed numerous oval-shaped fractures seemingly etched into the borehole wall. A theoretical examination of these stress-induced features identifies a unique and ephemeral set of stress distributions and magnitudes that are necessary for their production. Consequently, the ovals provide a basis for quantifying the magnitudes and orientations of the maximum and minimum horizontal principal stresses, SH and Sh, at this site. Vertical, truncated breakouts and horizontal tensile fractures define the spatial boundaries of the ovals. Explicit criteria for their occurrence are combined with estimates for various physical properties of the rock to yield a range of possible values for the horizontal principal stresses. The conspicuous oval geometry is completed by a curved fracture that joins the vertical and horizontal components. Its degree of curvature is delineated by the modified Griffith failure criterion and is directly related to the principal stress difference (SH - Sh). Matching a series of type curves corresponding to specific values for (SH - Sh) with the actual undistorted well bore images allows the magnitude of the stress difference to be further constrained. With a value for (SH - Sh) of 45 ?? 5 MPa the individual magnitudes of SH and Sh are determined more precisely. Final estimates for the horizontal principal stresses in DSDP Hole 504B at a depth of 1200 mbsf are 141 MPa ??? SH ??? 149 MPa and 91 MPa ??? Sh ??? 109 MPa. Stress magnitudes derived from this approach rely heavily upon the values of a variety of physical properties, and complementary laboratory measurements performed on relevant rock samples provide critical information. Uncertainties in

  1. Wide range stress intensity factor expressions for ASTM E 399 standard fracture toughness specimens

    NASA Technical Reports Server (NTRS)

    Srawley, J. E.

    1976-01-01

    For each of the two types of specimens, bend and compact, described previously for plane strain fracture toughness of materials, E 399, a polynominal expression is given for calculation of the stress intensity factor, K, from the applied force, P, and the specimen dimensions. It is explicitly stated, however, that these expressions should not be used outside the range of relative crack length, a/W, from 0.45 to 0.55. While this range is sufficient for the purpose of E 399, the same specimen types are often used for other purposes over a much wider range of a/W; for example, in the study of fatigue crack growth. Expressions are presented which are at least as accurate as those in E 399-74, and which cover much wider ranges of a/W: for the three-point bend specimen from 0 to 1; and for the compact specimen from 0.2 to 1. The range has to be restricted for the compact specimen because of the proximity of the loading pin holes to the crackline, which causes the stress intensity factor to be sensitive to small variations in dimensions when a/W is small. This is a penalty inherently associated with the compactness of the specimen.

  2. Finite element analysis to determine the stress distribution, displacement and safety factor on a microplate for the fractured jaw case

    NASA Astrophysics Data System (ADS)

    Pratama, Juan; Mahardika, Muslim

    2018-03-01

    Microplate is a connecting plate that can be used for jaw bone fixation. In the last two decades, microplate has been used so many times to help reconstruction of fractured jaw bone which is called mandibular bone or mandible bone. The plate is used to provide stable fixation of the fractured bone tissue during healing and reconstruction process. In this study Finite Element Analysis was used to predict the stress concentration and distribution on a microplate, displacement on the microplate and also to determine the safety factor of the microplate based on maximum allowable stress value, and finally to ascertain whether microplate is safe to use or not. The microplate was produced from punching process using titanium grade 1 (pure titanium) as material with a thickness of 500 µm. The results of the research indicated that the microplate was safe to use according to the maximum stress around the hole, displacement around the hole and also the safety factor of the microplate.

  3. Stress-Shielding Effect of Nitinol Swan-Like Memory Compressive Connector on Fracture Healing of Upper Limb

    NASA Astrophysics Data System (ADS)

    Fu, Q. G.; Liu, X. W.; Xu, S. G.; Li, M.; Zhang, C. C.

    2009-08-01

    In this article, the stress-shielding effect of a Nitinol swan-like memory compressive connector (SMC) is evaluated. Patients with fracture healing of an upper limb after SMC internal fixation or stainless steel plate fixation were randomly selected and observed comparatively. With the informed consent of the SMC group, minimal cortical bone under the swan-body and swan-neck was harvested; and in the steel plate fixation group, minimal cortical bone under the steel plate and opposite side to the steel plate was also harvested for observation. Main outcome measurements were taken such as osteocyte morphology, Harversian canal histological observation under light microscope; radiographic observation of fracture healing, and computed tomography quantitative scanning of cortical bone. As a conclusion, SMC has a lesser stress-shielding effect to fixed bone than steel plate. Finally, the mechanism of the lesser stress-shielding effect of SMC is discussed.

  4. Tibial plateau fracture after anterior cruciate ligament reconstruction: Role of the interference screw resorption in the stress riser effect.

    PubMed

    Thaunat, Mathieu; Nourissat, Geoffroy; Gaudin, Pascal; Beaufils, Philippe

    2006-06-01

    We report a case of tibial plateau fracture after previous anterior cruciate ligament (ACL) reconstruction using patellar tendon autograft and bioabsorbable screws 4 years previously. The fracture occurred through the tibial tunnel. The interference screw had undergone complete resorption and the tunnel widening had increased. The resorption of the interference screw did not simultaneously promote and foster the growth of surrounding bone tissue. Therefore, the area of reactive tissue left by the screw resorption in an enlarged bone tunnel may lead to vulnerability of the tibial plateau. Stress risers would occur following ACL reconstruction if either resorption is not complete or bony integration is not complete.

  5. Sensitivity and specificity of ultrasonography in early diagnosis of metatarsal bone stress fractures: a pilot study of 37 patients.

    PubMed

    Banal, Frédéric; Gandjbakhch, Frédérique; Foltz, Violaine; Goldcher, Alain; Etchepare, Fabien; Rozenberg, Sylvie; Koeger, Anne-Claude; Bourgeois, Pierre; Fautrel, Bruno

    2009-08-01

    To date, early diagnosis of stress fractures depends on magnetic resonance imaging (MRI) or bone scan scintigraphy, as radiographs are usually normal at onset of symptoms. These examinations are expensive or invasive, time-consuming, and poorly accessible. A recent report has shown the ability of ultrasonography (US) to detect early stress fractures. Our objective was to evaluate sensitivity and specificity of US versus dedicated MRI (0.2 Tesla), taken as the gold standard, in early diagnosis of metatarsal bone stress fractures. A case-control study from November 2006 to December 2007 was performed. All consecutive patients with mechanical pain and swelling of the metatarsal region for less than 3 months and with normal radiographs were included. US and dedicated MRI examinations of the metatarsal bones were performed the same day by experienced rheumatologists with expertise in US and MRI. Reading was undertaken blind to the clinical assessment and MRI/US results. Forty-one feet were analyzed on US and dedicated MRI from 37 patients (28 women, 9 men, mean age 52.7 +/- 14.1 yrs). MRI detected 13 fractures in 12 patients. Sensitivity of US was 83%, specificity 76%, positive predictive value 59%, and negative predictive value 92%. Positive likehood ratio was 3.45, negative likehood ratio 0.22. In cases of normal radiographs, US is indicated in the diagnosis of metatarsal bone stress fractures, as it is a low cost, noninvasive, rapid, and easy technique with good sensitivity and specificity. From these data, we propose a new imaging algorithm including US.

  6. Characterization and modeling of the stress and pore-fluid dependent acoustic properties of fractured porous rocks

    NASA Astrophysics Data System (ADS)

    Almrabat, Abdulhadi M.

    The thesis presents the results of a study of the characterization and modeling of the stress and pore-fluid dependent acoustic properties of fractured porous rocks. A new laboratory High Pressure and High Temperature (HPHT) triaxial testing system was developed to characterize the seismic properties of sandstone under different levels of effective stress confinement and changes in pore-fluid composition. An intact and fractured of Berea sandstones core samples were used in the experimental studies. The laboratory test results were used to develop analytical models for stress-level and pore-fluid dependent seismic velocity of sandstones. Models for stress-dependent P and S-wave seismic velocities of sandstone were then developed based on the assumption that stress-dependencies come from the nonlinear elastic response of micro-fractures contained in the sample under normal and shear loading. The contact shear stiffness was assumed to increase linearly with the normal stress across a micro-fracture, while the contact normal stiffness was assumed to vary as a power law with the micro-fracture normal stress. Both nonlinear fracture normal and shear contact models were validated by experimental data available in the literature. To test the dependency of seismic velocity of sandstone on changes in pore-fluid composition, another series of tests were conducted where P and S-wave velocities were monitored during injection of supercritical CO 2 in samples of Berea sandstone initially saturated with saline water and under constant confining stress. Changes in seismic wave velocity were measured at different levels of supercritical CO2 saturation as the initial saline water as pore-fluid was displaced by supercritical CO 2. It was found that the P- iv wave velocity significantly decreased while the S-wave velocity remained almost constant as the sample supercritical CO2 saturation increased. The dependency of the seismic velocity on changes on pore fluid composition during

  7. Expedited patient-specific assessment of contact stress exposure in the ankle joint following definitive articular fracture reduction.

    PubMed

    Kern, Andrew M; Anderson, Donald D

    2015-09-18

    Acute injury severity, altered joint kinematics, and joint incongruity are three important mechanical factors linked to post-traumatic osteoarthritis (PTOA). Finite element analysis (FEA) was previously used to assess the influence of increased contact stress due to joint incongruity on PTOA development. While promising agreement with PTOA development was seen, the inherent complexities of contact FEA limited the numbers of subjects that could be analyzed. Discrete element analysis (DEA) is a simplified methodology for contact stress computation, which idealizes contact surfaces as a bed of independent linear springs. In this study, DEA was explored as an expedited alternative to FEA contact stress exposure computation. DEA was compared to FEA using results from a previously completed validation study of two cadaveric human ankles, as well as a previous study of post-operative contact stress exposure in 11 patients with tibial plafond fracture. DEA-computed maximum contact stresses were within 19% of those experimentally measured, with 90% of the contact area having computed contact stress values within 1MPa of those measured. In the 11 fractured ankles, maximum contact stress and contact area differences between DEA and FEA were 0.85 ± 0.64 MPa and 22.5 ± 11.5mm(2). As a predictive measure for PTOA development, both DEA and FEA had 100% concordance with presence of OA (KL grade ≥ 2) and >95% concordance with KL grade at 2 years. These results support DEA as a reasonable alternative to FEA for computing contact stress exposures following surgical reduction of a tibial plafond fracture. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Increased mast cell numbers in a calcaneal tendon overuse model.

    PubMed

    Pingel, J; Wienecke, J; Kongsgaard, M; Behzad, H; Abraham, T; Langberg, H; Scott, A

    2013-12-01

    Tendinopathy is often discovered late because the initial development of tendon pathology is asymptomatic. The aim of this study was to examine the potential role of mast cell involvement in early tendinopathy using a high-intensity uphill running (HIUR) exercise model. Twenty-four male Wistar rats were divided in two groups: running group (n = 12); sedentary control group (n = 12). The running-group was exposed to the HIUR exercise protocol for 7 weeks. The calcaneal tendons of both hind limbs were dissected. The right tendon was used for histologic analysis using Bonar score, immunohistochemistry, and second harmonic generation microscopy (SHGM). The left tendon was used for quantitative polymerase chain reaction (qPCR) analysis. An increased tendon cell density in the runners were observed compared to the controls (P = 0.05). Further, the intensity of immunostaining of protein kinase B, P = 0.03; 2.75 ± 0.54 vs 1.17 ± 0.53, was increased in the runners. The Bonar score (P = 0.05), and the number of mast cells (P = 0.02) were significantly higher in the runners compared to the controls. Furthermore, SHGM showed focal collagen disorganization in the runners, and reduced collagen density (P = 0.03). IL-3 mRNA levels were correlated with mast cell number in sedentary animals. The qPCR analysis showed no significant differences between the groups in the other analyzed targets. The current study demonstrates that 7-week HIUR causes structural changes in the calcaneal tendon, and further that these changes are associated with an increased mast cell density. © 2013 The Authors. Scand J Med Sci Sports published by John Wiley & Sons Ltd.

  9. Tibio-talo-calcaneal arthrodesis by a retrograde intramedullary nail.

    PubMed

    Haaker, Rolf; Kohja, E Y; Wojciechowski, Mariusz; Gruber, Gerd

    2010-01-01

    The paper presents the results of tibio-talo-calcaneal fusions using Retrograde Nailing System and Bone Grafting. From May 2006 to January 2008, we performed 13 fusions in 11 consecutive patients with advanced ankle and hindfoot disease. Patients underwent 13 tibiotalocalcaneal fusions (2 patients had initial tibiotalocalcaneal fusion using screws and subsequently developed a non-union) and all 11 patients were available for follow up. The procedure was performed unilaterally in all cases; there were 4 males and 7 females. The average age at the time of surgery was 65.25 years (range 51-81 years). The average duration of follow-up was 8 months (range between 6-15 months). Solid fusion was achieved in all 11 cases. The average AOFAS score (maximum 78 points) improved from a pre-operative mean of 16 points [range 3 to 29] to a mean of 54 points [range 42 to 70], excluding the scores for stability and range of motion. Patient satisfaction scale (maximum 10 points) improved from 3 to 7 in both pain and function. 1- Arthrodesis should be considered only after all conservative treatments fails; it is one of the most challenging surgical procedures that must be undertaken with care in order to provide the best possible outcome. 2- Thorough evaluation and examination will help the surgeon to find the correct indication and identify patients who are not suitable for the procedure. It is crucial to assess the vascular and neurological status and to obtain weight-bearing radiographs (possibly CT) of the ankle to evaluate the deformity. 3- The optimal position of the ankle is in neutral flexion, 0-5 degrees valgus, and 10 degrees external rotation, similar to the contralateral foot and posterior translation of the talus under the tibia (5mm). 4- Tibio-talo-calcaneal fusion with retrograde nailing and bone grafting is a successful salvage procedure in severe ankle and hind foot arthrosis with deformity.

  10. Integrated In Situ Stress Estimation by Hydraulic Fracturing, Borehole Observations and Numerical Analysis at the EXP-1 Borehole in Pohang, Korea

    NASA Astrophysics Data System (ADS)

    Kim, Hanna; Xie, Linmao; Min, Ki-Bok; Bae, Seongho; Stephansson, Ove

    2017-12-01

    It is desirable to combine the stress measurement data produced by different methods to obtain a more reliable estimation of in situ stress. We present a regional case study of integrated in situ stress estimation by hydraulic fracturing, observations of borehole breakouts and drilling-induced fractures, and numerical modeling of a 1 km-deep borehole (EXP-1) in Pohang, South Korea. Prior to measuring the stress, World Stress Map (WSM) and modern field data in the Korean Peninsula are used to construct a best estimate stress model in this area. Then, new stress data from hydraulic fracturing and borehole observations is added to determine magnitude and orientation of horizontal stresses. Minimum horizontal principal stress is estimated from the shut-in pressure of the hydraulic fracturing measurement at a depth of about 700 m. The horizontal stress ratios ( S Hmax/ S hmin) derived from hydraulic fracturing, borehole breakout, and drilling-induced fractures are 1.4, 1.2, and 1.1-1.4, respectively, and the average orientations of the maximum horizontal stresses derived by field methods are N138°E, N122°E, and N136°E, respectively. The results of hydraulic fracturing and borehole observations are integrated with a result of numerical modeling to produce a final rock stress model. The results of the integration give in situ stress ratios of 1.3/1.0/0.8 ( S Hmax/ S V/ S hmin) with an average azimuth of S Hmax in the orientation range of N130°E-N136°E. It is found that the orientation of S Hmax is deviated by more than 40° clockwise compared to directions reported for the WSM in southeastern Korean peninsula.

  11. Rib stress fractures among rowers: definition, epidemiology, mechanisms, risk factors and effectiveness of injury prevention strategies.

    PubMed

    McDonnell, Lisa K; Hume, Patria A; Nolte, Volker

    2011-11-01

    Rib stress fractures (RSFs) can have serious effects on rowing training and performance and accordingly represent an important topic for sports medicine practitioners. Therefore, the aim of this review is to outline the definition, epidemiology, mechanisms, intrinsic and extrinsic risk factors, injury management and injury prevention strategies for RSF in rowers. To this end, nine relevant books, 140 journal articles, the proceedings of five conferences and two unpublished presentations were reviewed after searches of electronic databases using the keywords 'rowing', 'rib', 'stress fracture', 'injury', 'mechanics' and 'kinetics'. The review showed that RSF is an incomplete fracture occurring from an imbalance between the rate of bone resorption and the rate of bone formation. RSF occurs in 8.1-16.4% of elite rowers, 2% of university rowers and 1% of junior elite rowers. Approximately 86% of rowing RSF cases with known locations occur in ribs four to eight, mostly along the anterolateral/lateral rib cage. Elite rowers are more likely to experience RSF than nonelite rowers. Injury occurrence is equal among sweep rowers and scullers, but the regional location of the injury differs. The mechanism of injury is multifactorial with numerous intrinsic and extrinsic risk factors contributing. Posterior-directed resultant forces arising from the forward directed force vector through the arms to the oar handle in combination with the force vector induced by the scapula retractors during mid-drive, or repetitive stress from the external obliques and rectus abdominis in the 'finish' position, may be responsible for RSF. Joint hypomobility, vertebral malalignment or low bone mineral density may be associated with RSF. Case studies have shown increased risk associated with amenorrhoea, low bone density or poor technique, in combination with increases in training volume. Training volume alone may have less effect on injury than other factors. Large differences in seat and handle

  12. Stress inversion using borehole images and geometry evolution of the fractures in the Rittershoffen EGS project (Alsace, France).

    NASA Astrophysics Data System (ADS)

    Azzola, Jérôme; Valley, Benoît; Schmittbuhl, Jean; Genter, Albert; Hehn, Régis

    2017-04-01

    In the Upper Rhine Graben, several deep geothermal projects based on the Enhanced Geothermal System (EGS) exploit local geothermal reservoirs. The principle underlying this technology consists of increasing the hydraulic performances of the reservoir by stimulating natural fractures using different methods, in order to extract hot water with commercially flow rates. In this domain, the knowledge of the in-situ stress state is of central importance to predict the response of the rock mass to stimulations. Here we characterized the stress tensor from Ultrasonic Borehole Imager (UBI) in the open hole section of the EGS doublet located in Rittershoffen, France (in the Upper Rhine Graben). Interestingly extensive logging programs were leaded at different key moments of the development of the injection well using hydraulic, thermal and chemical stimulation (Baujard et al., 2017)1. The time lapse UBI dataset consists of images of the injection well before, shortly and lastly after the stimulation. The geometry of the induced fractures in compression (breakouts) picked on the UBI images are used to determine the orientation of the in-situ stress tensor. The magnitude of the principal stresses is deduced from the drilling data. The magnitude of the maximum horizontal principal stress is evaluated using an inversion method with three failure criteria (Mohr-Coulomb, Mogi-Coulomb and modified Hoek-Brown criterion) and under the assumption of a vertical or a deviated well. Moreover, the characteristic of the dataset enables the analysis of the evolution of the borehole fracturing, as the deepening or widening of the induced fractures. The correlation of the UBI image allows firstly to determine the tool trajectory and to adapt the post and pre-stimulation images. It secondly leads to the estimation of a complete displacement field which characterizes the deformation induced by the stimulations. Even if the variable image quality deeply conditions the comparison, the considered

  13. [Arthroscopy-guided fracture management. Ankle joint and calcaneus].

    PubMed

    Schoepp, C; Rixen, D

    2013-04-01

    Arthroscopic fracture management of the ankle and calcaneus requires a differentiated approach. The aim is to minimize surgical soft tissue damage and to visualize anatomical fracture reduction arthroscopically. Moreover, additional cartilage damage can be detected and treated. The arthroscopic approach is limited by deep impressions of the joint surface needing cancellous bone grafting, by multiple fracture lines on the articular side and by high-grade soft tissue damage. An alternative to the minimally invasive arthroscopic approach is open arthroscopic reduction in conventional osteosynthesis. This facilitates correct assessment of surgical reduction of complex calcaneal fractures, otherwise remaining non-anatomical reduction might not be fluoroscopically detected during surgery.

  14. Biomechanical modeling of acetabular component polyethylene stresses, fracture risk, and wear rate following press-fit implantation.

    PubMed

    Ong, Kevin L; Rundell, Steve; Liepins, Imants; Laurent, Ryan; Markel, David; Kurtz, Steven M

    2009-11-01

    Press-fit implantation may result in acetabular component deformation between the ischial-ilial columns ("pinching"). The biomechanical and clinical consequences of liner pinching due to press-fit implantation have not been well studied. We compared the effects of pinching on the polyethylene fracture risk, potential wear rate, and stresses for two different thickness liners using computational methods. Line-to-line ("no pinch") reaming and 2 mm underreaming press fit ("pinch") conditions were examined for Trident cups with X3 polyethylene liner wall thicknesses of 5.9 mm (36E) and 3.8 mm (40E). Press-fit cup deformations were measured from a foam block configuration. A hybrid material model, calibrated to experimentally determined stress-strain behavior of sequentially annealed polyethylene, was applied to the computational model. Molecular chain stretch did not exceed the fracture threshold in any cases. Nominal shell pinch of 0.28 mm was estimated to increase the volumetric wear rate by 70% for both cups and peak contact stresses by 140 and 170% for the 5.9 and 3.8 mm-thick liners, respectively. Although pinching increases liner stresses, polyethylene fracture is highly unlikely, and the volumetric wear rates are likely to be low compared to conventional polyethylene. (c) 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  15. Section modulus is the optimum geometric predictor for stress fractures and medial tibial stress syndrome in both male and female athletes.

    PubMed

    Franklyn, Melanie; Oakes, Barry; Field, Bruce; Wells, Peter; Morgan, David

    2008-06-01

    Various tibial dimensions and geometric parameters have been linked to stress fractures in athletes and military recruits, but many mechanical parameters have still not been investigated. Sedentary people, athletes with medial tibial stress syndrome, and athletes with stress fractures have smaller tibial geometric dimensions and parameters than do uninjured athletes. Cohort study; Level of evidence, 3. Using a total of 88 subjects, male and female patients with either a tibial stress fracture or medial tibial stress syndrome were compared with both uninjured aerobically active controls and uninjured sedentary controls. Tibial scout radiographs and cross-sectional computed tomography images of all subjects were scanned at the junction of the midthird and distal third of the tibia. Tibial dimensions were measured directly from the films; other parameters were calculated numerically. Uninjured exercising men have a greater tibial cortical cross-sectional area than do their sedentary and injured counterparts, resulting in a greater value of some other cross-sectional geometric parameters, particularly the section modulus. However, for women, the cross-sectional areas are either not different or only marginally different, and there are few tibial dimensions or geometric parameters that distinguish the uninjured exercisers from the sedentary and injured subjects. In women, the main difference between the groups was the distribution of cortical bone about the centroid as a result of the different values of section modulus. Last, medial tibial stress syndrome subjects had smaller tibial cross-sectional dimensions than did their uninjured exercising counterparts, suggesting that medial tibial stress syndrome is not just a soft-tissue injury but also a bony injury. The results show that in men, the cross-sectional area and the section modulus are the key parameters in the tibia to distinguish exercise and injury status, whereas for women, it is the section modulus only.

  16. Effect of far-field stresses and residual stresses incorporation in predicting fracture toughness of carbon nanotube reinforced yttria stabilized zirconia

    NASA Astrophysics Data System (ADS)

    Mahato, Neelima; Nisar, Ambreen; Mohapatra, Pratyasha; Rawat, Siddharth; Ariharan, S.; Balani, Kantesh

    2017-10-01

    Yttria-stabilized zirconia (YSZ) is a potential thermal insulating ceramic for high temperature applications (>1000 °C). YSZ reinforced with multi-walled carbon nanotubes (MWNTs) was processed via spark plasma sintering to produce dense, crack-free homogeneous sample and avoid any degradation of MWNTs when sintered using conventional routes. Despite porosity, the addition of MWNT has a profound effect in improving the damage tolerance of YSZ by allowing the retention of tetragonal phase. However, at some instances, the crack lengths in the MWNT reinforced YSZ matrices have been found to be longer than the standalone counterparts. Therefore, it becomes inappropriate to apply Anstis equation to calculate fracture toughness values. In this regard, a combined analytical cum numerical method is used to estimate the theoretical fracture toughness and quantitatively analyze the mechanics of matrix cracking in the reinforced composite matrices incorporating the effects of various factors (such as far-field stresses, volume fraction of MWNTs, change in the modulus and Poisson's ratio values along with the increase in porosity, and bridging and phase transformation mechanism) affecting the fracture toughness of YSZ-MWNT composites. The results suggest that the incorporation of far-field stresses cannot be ignored in estimating the theoretical fracture toughness of YSZ-MWNT composites.

  17. Addition of perfluorocarbons to alginate hydrogels significantly impacts molecular transport and fracture stress.

    PubMed

    White, Joseph C; Stoppel, Whitney L; Roberts, Susan C; Bhatia, Surita R

    2013-02-01

    Perfluorocarbons (PFCs) are used in biomaterial formulations to increase oxygen (O(2) ) tension and create a homogeneous O(2) environment in three-dimensional tissue constructs. It is unclear how PFCs affect mechanical and transport properties of the scaffold, which are critical for robustness, intracellular signaling, protein transport, and overall device efficacy. In this study, we investigate composite alginate hydrogels containing a perfluorooctyl bromide (PFOB) emulsion stabilized with Pluronic(®) F68 (F68). We demonstrate that PFC addition significantly affects biomaterial properties and performance. Solution and hydrogel mechanical properties and transport of representative hydrophilic (riboflavin), hydrophobic (methyl and ethyl paraben), and protein (bovine serum albumin, BSA) solutes were compared in alginate/F68 composite hydrogels with or without PFOB. Our results indicate that mechanical properties of the alginate/F68/PFOB hydrogels are not significantly affected under small strains, but a significant decrease fracture stress is observed. The effective diffusivity D(eff) of hydrophobic small molecules decreases with PFOB emulsion addition, yet the D(eff) of hydrophilic small molecules remained unaffected. For BSA, the D(eff) increased and the loading capacity decreased with PFOB emulsion addition. Thus, a trade-off between the desired increased O(2) supply provided by PFCs and the mechanical weakening and change in transport of cellular signals must be carefully considered in the design of biomaterials containing PFCs. Copyright © 2012 Wiley Periodicals, Inc.

  18. Transdermal drug delivery: feasibility for treatment of superficial bone stress fractures.

    PubMed

    Aghazadeh-Habashi, Ali; Yang, Yang; Tang, Kathy; Lőbenberg, Raimar; Doschak, Michael R

    2015-12-01

    Transdermal drug delivery offers the promise of effective drug therapy at selective sites of pathology whilst reducing systemic exposure to the pharmaceutical agents in off-target organs and tissues. However, that strategy is often limited to cells comprising superficial tissues of the body (rarely to deeper bony structures) and mostly indicated with small hydrophobic pharmacological agents, such as steroid hormones and anti-inflammatory gels to skin, muscle, and joints. Nonetheless, advances in transdermal liposomal formulation have rendered the ability to readily incorporate pharmacologically active hydrophilic drug molecules and small peptide biologics into transdermal dosage forms to impart the effective delivery of those bioactive agents across the skin barrier to underlying superficial tissue structures including bone, often enhanced by some form of electrical, chemical, and mechanical facilitation. In the following review, we evaluate transdermal drug delivery systems, with a particular focus on delivering therapeutic agents to treat superficial bone pain, notably stress fractures. We further introduce and discuss several small peptide hormones active in bone (such as calcitonins and parathyroid hormone) that have shown potential for transdermal delivery, often under the added augmentation of transdermal drug delivery systems that employ lipo/hydrophilicity, electric charge, and/or microprojection facilitation across the skin barrier.

  19. An epiphyseal stress fracture of the foot and shin splints in an anomalous calf muscle in a runner.

    PubMed Central

    Percy, E. C.; Gamble, F. O.

    1980-01-01

    The following case is presented as one of unusual foot and leg lesions encountered in an adolescent long-distance runner. The associated problems of a first metatarsal Salter Harris type II epiphyseal stress fracture, and an accessory calf muscle with "shin splints" in the contralateral leg are discussed. Treatment of these conditions is outlined with eventual return to full function by the athlete. Images p110-a Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 PMID:7407448

  20. Measurement of fracture stress for 6000-series extruded aluminum alloy tube using multiaxial tube expansion testing method

    NASA Astrophysics Data System (ADS)

    Nagai, Keisuke; Kuwabara, Toshihiko; Ilinich, Andrey; Luckey, George

    2018-05-01

    A servo-controlled tension-internal pressure testing machine with an optical 3D digital image correlation system (DIC) is used to measure the multiaxial deformation behavior of an extruded aluminum alloy tube for a strain range from initial yield to fracture. The outer diameter of the test sample is 50.8 mm and wall thickness 2.8 mm. Nine linear stress paths are applied to the specimens: σɸ (axial true stress component) : σθ (circumferential true stress component) = 1:0, 4:1, 2:1, 4:3, 1:1, 3:4, 1:2, 1:4, and 0:1. The equivalent strain rate is approximately 5 × 10-4 s-1 constant. The forming limit curve (FLC) and forming limit stress curve (FLSC) are also measured. Moreover, the average true stress components inside a localized necking area are determined for each specimen from the thickness strain data for the localized necking area and the geometry of the fracture surface.

  1. "Shin splint" syndrome and tibial stress fracture in the same patient diagnosed by means of (99m)Tc-HMDP SPECT/CT.

    PubMed

    Vicente, Justo Serrano; Grande, Maria Luz Domínguez; Torre, Jose Rafael Infante; Madrid, Juan Ignacio Rayo; Barquero, Carmen Durán; Bernardo, Lucía García; Sánchez, Román Sánchez

    2013-04-01

    We show a patient who presented leg pain triggered by intense exercise. The most likely diagnosis was a possible tibial stress fracture or a "shin splint" syndrome (soleus enthesopathy). We performed a bone scintigraphy including SPECT/CT that revealed the presence of the two concomitant pathologies. SPECT/CT identified the hot spot superimposed with bone lesion in the tibial stress fracture and only remodeling activity without evidence of cortical lesions in the enthesopathy processes.

  2. Stress and Fracture Analyses Under Elastic-plastic and Creep Conditions: Some Basic Developments and Computational Approaches

    NASA Technical Reports Server (NTRS)

    Reed, K. W.; Stonesifer, R. B.; Atluri, S. N.

    1983-01-01

    A new hybrid-stress finite element algorith, suitable for analyses of large quasi-static deformations of inelastic solids, is presented. Principal variables in the formulation are the nominal stress-rate and spin. A such, a consistent reformulation of the constitutive equation is necessary, and is discussed. The finite element equations give rise to an initial value problem. Time integration has been accomplished by Euler and Runge-Kutta schemes and the superior accuracy of the higher order schemes is noted. In the course of integration of stress in time, it has been demonstrated that classical schemes such as Euler's and Runge-Kutta may lead to strong frame-dependence. As a remedy, modified integration schemes are proposed and the potential of the new schemes for suppressing frame dependence of numerically integrated stress is demonstrated. The topic of the development of valid creep fracture criteria is also addressed.

  3. In situ stress, natural fracture distribution, and borehole elongation in the Auburn Geothermal Well, Auburn, New York

    Hickman, Stephen H.; Healy, John H.; Zoback, Mark D.

    1985-01-01

    Hydraulic fracturing stress measurements and a borehole televiewer survey were conducted in a 1.6‐km‐deep well at Auburn, New York. This well, which was drilled at the outer margin of the Appalachian Fold and Thrust Belt in the Appalachian Plateau, penetrates approximately 1540 m of lower Paleozoic sedimentary rocks and terminates 60 m into the Precambrian marble basement. Analysis of the hydraulic fracturing tests indicates that the minimum horizontal principal stress increases in a nearly linear fashion from 9.9±0.2 MPa at 593 m to 30.6±0.4 MPa at 1482 m. The magnitude of the maximum horizontal principal stress increases in a less regular fashion from 13.8±1.2 MPa to 49.0±2.0 MPa over the same depth range. The magnitudes of the horizontal principal stresses relative to the calculated overburden stress are somewhat lower than is the norm for this region and are indicative of a strike‐slip faulting regime that, at some depths, is transitional to normal faulting. As expected from the relative aseismicity of central New York State, however, analysis of the magnitudes of the horizontal principal stresses indicates, at least to a depth of 1.5 km, that frictional failure on favorably oriented preexisting fault planes is unlikely. Orientations of the hydraulic fractures at 593 and 919 m indicate that the azimuth of the maximum horizontal principal stress at Auburn is N83°E±15°, in agreement with other stress field indicators for this region. The borehole televiewer log revealed a considerable number of planar features in the Auburn well, the great majority of which are subhorizontal (dips < 5°) and are thought to be bedding plane washouts or drill bit scour marks. In addition, a smaller number of distinct natural fractures were observed on the borehole televiewer log. Of these, the distinct steeply dipping natural fractures in the lower half of the sedimentary section at Auburn tend to strike approximately east‐west, while those in the upper part of the

  4. A Comparison of Removal Rates of Headless Screws Versus Headed Screws in Calcaneal Osteotomy.

    PubMed

    Kunzler, Daniel; Shazadeh Safavi, Pejma; Jupiter, Daniel; Panchbhavi, Vinod K

    2017-11-01

    Calcaneal osteotomy has been used to successfully treat both valgus and varus hindfoot deformities. Pain associated with implanted hardware may lead to further surgical intervention for hardware removal. Headless screws have been used to reduce postoperative hardware-associated pain and accompanying hardware removal, but data proving their effectiveness in this regard is lacking. The purpose of this study is to compare the rates of removal of headed and headless screws utilized in calcaneal osteotomy. We conducted a retrospective chart review of 74 patients who underwent calcaneal osteotomy between January 2010 and December 2014. The cohort was divided into 2 groups by fixation method: a headed screw and a headless screw group. Bivariate associations between infection or hardware removal, and screw type, screw head width, gender, smoking status, alcohol, hypertension, diabetes, hyperlipidemia, age, and body mass index were assessed using t-tests and Fisher's exact/χ 2 tests for continuous and discrete variables, respectively. Headed screws were removed more frequently than headless screws (P < .0001): 15 of 30 (50%) feet that received headed screws and 4 of 44 (9%) of feet that received headless screws underwent subsequent revision for screw removal. In all cases, screws were removed because of pain. The calcaneal union rate was 100% in both cohorts. The rate of screw removal in calcaneal osteotomies is significantly lower in patients who receive headless screws than in those receiving headed screws. Level IV.

  5. Modified tension band wiring fixation for avulsion fractures of the calcaneus in osteoporotic bone: a review of three patients.

    PubMed

    Nagura, Issei; Fujioka, Hiroyuki; Kurosaka, Masahiro; Mori, Hiroyuki; Mitani, Makoto; Ozaki, Akihiro; Fujii, Hideo; Nabeshima, Yuji

    2012-01-01

    Calcaneal avulsion fractures are not uncommon, and they are probably more likely in patients with osteoporosis. Closed manipulation for this type of fracture often fails to achieve acceptable reduction, and open reduction and internal fixation are usually required. However, open reduction and internal fixation with either a lag screw or Steinmann pins do not provide satisfactory fixation in patients with diabetes and elderly patients because of the presence of porotic bone. Levi described a tension band fixation system used to treat a calcaneal avulsion fracture using a simple technique performed with a transverse Kirschner wire through the os calcaneus, securing a figure-of-8 metal tension band wiring to the fragment. We report the successful treatment of 3 patients with calcaneal avulsion fractures using a modified tension band wiring technique, resulting in satisfactory recovery. Re-displacement of the fragment during the initial follow-up period was not reported, and bony union was achieved in all patients. We believe this technique is a useful surgical option for the treatment of calcaneal avulsion fractures. Copyright © 2012 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  6. Foot Kinematics Differ Between Runners With and Without a History of Navicular Stress Fractures

    PubMed Central

    Becker, James; James, Stanley; Osternig, Louis; Chou, Li-Shan

    2018-01-01

    Background: A navicular stress fracture (NSF) is a common and high-risk injury in distance runners. It is not clear whether there are differences in foot structure and function between runners who have and those who have not sustained an NSF. Purpose/Hypothesis: This study compared foot structure, range of motion, and biomechanics between runners with a history of unilateral NSFs and runners who had never sustained this injury. The hypothesis was that runners with a history of NSFs will have less dorsiflexion and subtalar range of motion in a clinical examination and greater rearfoot eversion and higher eversion velocity while running than either the noninvolved feet or healthy controls. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Seven runners who sustained an NSF were matched with 7 controls without this injury history. Participants underwent a clinical orthopaedic examination, followed by a 3-dimensional running gait analysis. Clinical examination variables, foot kinematics, and ground-reaction forces were compared between injured and noninjured feet within the NSF group and between the NSF group and control group. Results: The NSF group demonstrated less plantar flexion on the clinical examination than the control group (P = .034, effect size [ES] = 0.69). The involved feet of the NSF group demonstrated greater rearfoot eversion excursion, greater eversion velocity, and reduced forefoot abduction excursion than either the noninvolved feet of the NSF group (P = .015, ES = 1.73; P = .015, ES = 1.86; and P = .015, ES = 0.96, respectively) or the control group (P = .012, ES = 1.40; P = .016, ES = 0.49; and P = .005, ES = 1.60, respectively). Conclusion: There are differences in foot kinematics but not ground-reaction forces, foot structure, or passive range of motion between runners who have and those who have not sustained an NSF. Runners who demonstrate increased rearfoot eversion and reduced forefoot abduction during stance may be more at

  7. Rib stress fractures among rowers: a systematic review on return to sports, risk factors and prevention.

    PubMed

    D'Ailly, Philip N; Sluiter, Judith K; Kuijer, Paul P

    2016-06-01

    Rib stress fractures (RSFs) are injuries frequently sustained by elite rowers with an injury rate of 8-16% over the course of a rowing career, resulting in negative effects on training and performance. For clinical management, the aim of this review was to describe time to return to sports, summarize potentially preventive measures and appraise the evidence on risk factors. A search strategy was performed in PubMed, SportDiscus, Web of Science and Embase till June 1st 2015. All studies were graded on their quality. The search resulted in 124 studies, of which 17 were included: Ten reported on return to sports, 17 reported on risk factors and nine on preventive measures. For return to sports, nine studies mentioned a loss of training of 4-6 weeks. The shortest period was one week and the longest 16 weeks. For risk factors, insufficient or conflicting evidence was found for changes in the training program, incorrect rowing technique, female gender, low bone mineral density, inadequate equipment, and training type. For prevention, gradual changes in the training program, alertness on the part of coaches and clinicians, and supplementation of diet and hormones are suggested as effective measures. However, no effect studies have been found. The main outcome of this review on RSFs is that little evidence is available on return to sports, risk factors and preventive measures. Coaches and clinicians should carefully guide and assist rowers suffering from RSFs in off training and in the subsequent training period to regain their pre-injury level.

  8. Experimental and finite element analysis of tibial stress fractures using a rabbit model.

    PubMed

    Franklyn, Melanie; Field, Bruce

    2013-01-01

    To determine if rabbit models can be used to quantify the mechanical behaviour involved in tibial stress fracture (TSF) development. Fresh rabbit tibiae were loaded under compression using a specifically-designed test apparatus. Weights were incrementally added up to a load of 30 kg and the mechanical behaviour of the tibia was analysed using tests for buckling, bone strain and hysteresis. Structural mechanics equations were subsequently employed to verify that the results were within the range of values predicted by theory. A finite element (FE) model was developed using cross-sectional computer tomography (CT) images scanned from one of the rabbit bones, and a static load of 6 kg (1.5 times the rabbit's body weight) was applied to represent running. The model was validated using the experimental strain gauge data, then geometric and elemental convergence tests were performed in order to find the minimum number of cross-sectional scans and elements respectively required for convergence. The analysis was then performed using both the model and the experimental results to investigate the mechanical behaviour of the rabbit tibia under compressive load and to examine crack initiation. The experimental tests showed that under a compressive load of up to 12 kg, the rabbit tibia demonstrates linear behaviour with little hysteresis. Up to 30 kg, the bone does not fail by elastic buckling; however, there are low levels of tensile stress which predominately occur at and adjacent to the anterior border of the tibial midshaft: this suggests that fatigue failure occurs in these regions, since bone under cyclic loading initially fails in tension. The FE model predictions were consistent with both mechanics theory and the strain gauge results. The model was highly sensitive to small changes in the position of the applied load due to the high slenderness ratio of the rabbit's tibia. The modelling technique used in the current study could have applications in the development of

  9. Pseudoelastic intramedullary nailing for tibio-talo-calcaneal arthrodesis.

    PubMed

    Yakacki, Christopher M; Gall, Ken; Dirschl, Douglas R; Pacaccio, Douglas J

    2011-03-01

    Tibio-talo-calcaneal (TTC) arthrodesis is a procedure to treat severe ankle arthropathy by providing a pain-free and stable fusion. Intramedullary (IM) nails offer a method of internal fixation for TTC arthrodesis by providing compressive stability, as well as shear and torsional rigidity. IM nails have been developed to apply compression to the TTC complex during installation; however, current designs are highly susceptible to a loss of compression when exposed to small amounts of bone resorption and cyclic loading. Nickel titanium (NiTi) is a shape-memory alloy capable of recovering large amounts of deformation via shape-memory or pseudoelasticity. Currently, the next generation of IM nails is being developed to utilize the adaptive, pseudoelastic properties of NiTi and provide a fusion nail that is resistant to loss of compression or loosening. Specifically, the pseudoelastic IM nail contains an internal NiTi compression element that applies sustained compression during the course of fusion, analogous to external fixators. © 2011 Expert Reviews Ltd

  10. Fractures, stress and fluid flow prior to stimulation of well 27-15, Desert Peak, Nevada, EGS project

    Davatzes, Nicholas C.; Hickman, Stephen H.

    2009-01-01

    A suite of geophysical logs has been acquired for structural, fluid flow and stress analysis of well 27-15 in the Desert Peak Geothermal Field, Nevada, in preparation for stimulation and development of an Enhanced Geothermal System (EGS). Advanced Logic Technologies Borehole Televiewer (BHTV) and Schlumberger Formation MicroScanner (FMS) image logs reveal extensive drilling-induced tensile fractures, showing that the current minimum compressive horizontal stress, Shmin, in the vicinity of well 27-15 is oriented along an azimuth of 114±17°. This orientation is consistent with the dip direction of recently active normal faults mapped at the surface and with extensive sets of fractures and some formation boundaries seen in the BHTV and FMS logs. Temperature and spinner flowmeter surveys reveal several minor flowing fractures that are well oriented for normal slip, although over-all permeability in the well is quite low. These results indicate that well 27-15 is a viable candidate for EGS stimulation and complements research by other investigators including cuttings analysis, a reflection seismic survey, pressure transient and tracer testing, and micro-seismic monitoring.

  11. Does a positive ankle stress test indicate the need for operative treatment after lateral malleolus fracture? A preliminary report.

    PubMed

    Koval, Kenneth J; Egol, Kenneth A; Cheung, Yvonne; Goodwin, Douglass W; Spratt, Kevin F

    2007-08-01

    At our institution, a standardized protocol using magnetic resonance imaging (MRI) to evaluate ankle stability and need for surgery following a positive manual stress test for isolated lateral malleolus fractures has been used. The purpose of this study was to evaluate the results using this standardized protocol. Retrospective review. University teaching hospital. : Twenty-one patients who had a positive ankle stress test (>or=5 mm clear space widening) after isolated Weber B lateral malleolus fracture were further evaluated by MRI to determine the status of the deep deltoid ligament. If the MRI showed the deltoid ligament was completely disrupted, the patient was advised to have operative ankle repair. However, if the MRI demonstrated that the deep deltoid was intact or only partially disrupted, the patient was treated nonoperatively in a walking boot with weightbearing as tolerated ambulation. Patients were followed until fracture union and contacted at 12-month minimum follow-up to determine outcomes by radiographic evaluation, health related quality of life (HRQOL) based on Short Form (SF)-36 results and functional outcomes based on the American Orthopaedic Foot and Ankle (AOFAS) and patient report of treatment satisfaction. Twenty-one patients had an MRI after a positive ankle stress test and comprised the study group. There were 12 men and 9 women with an average age of 27 years (range, 16-62 years). Absolute medial clear space measurement on stress testing ranged from 5 to 8 mm. In all, 19 of 21 patients (90%) had evidence of partially torn deep deltoid ligament on MRI and were treated nonoperatively, whereas two patients had MRI findings of a complete deep deltoid injury and underwent surgical treatment. There were no statistically significant correlations between the medial clear space measurements and MRI documentation of complete deltoid ligament rupture. All fractures united without evidence of residual medial clear space widening or posttraumatic

  12. Double row anchor fixation: a novel technique for a diabetic calanceal insufficiency avulsion fracture.

    PubMed

    Greenhagen, Robert M; Highlander, Peter D; Burns, Patrick R

    2012-01-01

    Avulsion fractures of the calcaneal tuberosity represent only 1.3% to 2.7% of calcaneal fractures. These fractures are common pathologically in nature and attributed to decreased bone mineral density. Calcaneal insufficiency avulsion (CIA) fracture in patients with diabetes mellitus is most likely due to Charcot neuroarthropathy (CN) as described by the Brodsky classification (Brodsky 3B). Traditional open reduction and internal fixation is difficult in all calcaneal avulsion fractures because of poor bone quality. The authors report the first known description of the use of fracture fragment excision and double row anchor fixation.A 39-year-old woman with type I diabetes mellitus and a history of CN presented with an avulsion fracture of the calcaneal tuberosity. Excision of the fracture fragment and a gastrocnemius recession and reattachment of the Achilles tendon with double row anchor fixation to the calcaneus were performed. At 1 year, the patient's American Orthopaedic Foot & Ankle Society rearfoot score improved from 27/100 to 88/100. CIA fractures are an infrequently described injury. Because diabetes mellitus is frequently associated with this disease, it most likely represents a CN event. Traditionally, CIA fractures have been operatively treated with open reduction internal fixation. Previous authors have described difficulty with fixation because of poor quality. In the current report, the authors describe a novel operative approach to CIA fractures through the use of double row anchor fixation and excision of the fracture fragments. The authors feel that this previously undescribed treatment is superior to traditional methods and may serve as a new treatment option for all patients who have sustained this unusual pathology regardless of the underlying cause. The current authors provide a novel operative technique that provides inherent advantages to the traditional repair of CIA fractures. We believe CIA fractures represent a CN-type event and care

  13. Water Stress from High-Volume Hydraulic Fracturing Potentially Threatens Aquatic Biodiversity and Ecosystem Services in Arkansas, United States.

    PubMed

    Entrekin, Sally; Trainor, Anne; Saiers, James; Patterson, Lauren; Maloney, Kelly; Fargione, Joseph; Kiesecker, Joseph; Baruch-Mordo, Sharon; Konschnik, Katherine; Wiseman, Hannah; Nicot, Jean-Philippe; Ryan, Joseph N

    2018-02-20

    Demand for high-volume, short duration water withdrawals could create water stress to aquatic organisms in Fayetteville Shale streams sourced for hydraulic fracturing fluids. We estimated potential water stress using permitted water withdrawal volumes and actual water withdrawals compared to monthly median, low, and high streamflows. Risk for biological stress was considered at 20% of long-term median and 10% of high- and low-flow thresholds. Future well build-out projections estimated potential for continued stress. Most water was permitted from small, free-flowing streams and "frack" ponds (dammed streams). Permitted 12-h pumping volumes exceeded median streamflow at 50% of withdrawal sites in June, when flows were low. Daily water usage, from operator disclosures, compared to median streamflow showed possible water stress in 7-51% of catchments from June-November, respectively. If 100% of produced water was recycled, per-well water use declined by 25%, reducing threshold exceedance by 10%. Future water stress was predicted to occur in fewer catchments important for drinking water and species of conservation concern due to the decline in new well installations and increased use of recycled water. Accessible and precise withdrawal and streamflow data are critical moving forward to assess and mitigate water stress in streams that experience high-volume withdrawals.

  14. Water stress from high-volume hydraulic fracturing potentially threatens aquatic biodiversity and ecosystem services in Arkansas, United States

    Entrekin, Sally; Trainor, Anne; Saiers, James; Patterson, Lauren; Maloney, Kelly O.; Fargione, Joseph; Kiesecker, Joseph M.; Baruch-Mordo, Sharon; Konschnik, Katherine E.; Wiseman, Hannah; Nicot, Jean-Philippe; Ryan, Joseph N.

    2018-01-01

    Demand for high-volume, short duration water withdrawals could create water stress to aquatic organisms in Fayetteville Shale streams sourced for hydraulic fracturing fluids. We estimated potential water stress using permitted water withdrawal volumes and actual water withdrawals compared to monthly median, low, and high streamflows. Risk for biological stress was considered at 20% of long-term median and 10% of high- and low-flow thresholds. Future well build-out projections estimated potential for continued stress. Most water was permitted from small, free-flowing streams and “frack” ponds (dammed streams). Permitted 12-h pumping volumes exceeded median streamflow at 50% of withdrawal sites in June, when flows were low. Daily water usage, from operator disclosures, compared to median streamflow showed possible water stress in 7–51% of catchments from June–November, respectively. If 100% of produced water was recycled, per-well water use declined by 25%, reducing threshold exceedance by 10%. Future water stress was predicted to occur in fewer catchments important for drinking water and species of conservation concern due to the decline in new well installations and increased use of recycled water. Accessible and precise withdrawal and streamflow data are critical moving forward to assess and mitigate water stress in streams that experience high-volume withdrawals.

  15. Role of the calcaneal heel pad and polymeric shock absorbers in attenuation of heel strike impact.

    PubMed

    Noe, D A; Voto, S J; Hoffmann, M S; Askew, M J; Gradisar, I A

    1993-01-01

    The capacity of the calcaneal heel pad, with and without augmentation by a polymeric shock absorbing material (Sorbothane 0050), to attenuate heel strike impulses has been studied using five fresh human cadaveric lower leg specimens. The specimens, instrumented with an accelerometer, were suspended and impacted with a hammer; a steel rod was similarly suspended and impacted. The calcaneal heel pad attenuated the peak accelerations by 80%. Attenuations of up to 93% were achieved by the shock absorbing material when tested against the steel rod; however, when tested in series with the calcaneal heel pad, the reduction in peak acceleration due to the shock absorbing material dropped to 18%. Any evaluation of the effectiveness of shock absorbing shoe materials must take into account their mechanical interaction with the body.

  16. Minimally Invasive Calcaneal Displacement Osteotomy Site Using a Reference Kirschner Wire: A Technique Tip.

    PubMed

    Lee, Moses; Guyton, Gregory P; Zahoor, Talal; Schon, Lew C

    2016-01-01

    As a standard open approach, the lateral oblique incision has been widely used for calcaneal displacement osteotomy. However, just as with other orthopedic procedures that use an open approach, complications, including wound healing problems and neurovascular injury in the heel, have been reported. To help avoid these limitations, a percutaneous technique using a Shannon burr for calcaneal displacement osteotomy was introduced. However, relying on a free-hand technique without direct visualization at the osteotomy site has been a major obstacle for this technique. To address this problem, we developed a technical tip using a reference Kirschner wire. A reference Kirschner wire technique provides a reliable and accurate guide for minimally invasive calcaneal displacement osteotomy. Also, the technique should be easy to learn for surgeons new to the procedure. Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  17. Analysis of stress-strain, fracture and ductility behavior of aluminum matrix composites containing discontinuous silicon carbide reinforcement

    NASA Technical Reports Server (NTRS)

    Mcdanels, D. L.

    1984-01-01

    Mechanical properties and stress-strain behavior for several types of commercially fabricated aluminum matrix composites, containing up to 40 vol % discontinuous SiC whisker, nodule, or particulate reinforcement were evaluated. It was found that the elastic modulus of the composites was isotropic, to be independent of type of reinforcement, and to be controlled solely by the volume percentage of SiC reinforcement present. The yield/tensile strengths and ductility were controlled primarily by the matrix alloy and temper condition. Ductility decreased with increasing reinforcement content, however, the fracture strains observed were higher than those reported in the literature for this type of composite. This increase in fracture strain is attributed to cleaner matrix powder and increased mechanical working during fabrication. Conventional aluminum and titanium structural alloys were compared and have shown that the properties of these low cost, lightweight composites have good potential for application to aerospace structures.

  18. Central Japan's Atera Active Fault's Wide-Fractured Zone: An Examination of the Structure and In-situ Crustal Stress

    NASA Astrophysics Data System (ADS)

    Ikeda, R.; Omura, K.; Matsuda, T.; Mizuochi, Y.; Uehara, D.; Chiba, A.; Kikuchi, A.; Yamamoto, T.

    2001-12-01

    In-situ downhole measurements and coring within and around an active fault zone are needed to better understand the structure and material properties of fault rocks as well as the physical state of active faults and intra-plate crust. Particularly, the relationship between the stress concentration state and the heterogeneous strength of an earthquake fault zone is important to estimate earthquake occurrence mechanisms which correspond to the prediction of an earthquake. It is necessary to compare some active faults in different conditions of the chrysalis stage and their relation to subsequent earthquake occurrence. To better understand such conditions, "Active Fault Zone Drilling Project" has been conducted in the central part of Japan by the National Research Institute for Earth Science and Disaster Prevention. The Nojima fault which appeared on the surface by the 1995 Great Kobe earthquake (M=7.2) and the Neodani fault created by the 1981 Nobi earthquake, the greatest inland earthquake M=8.0 in Japan, have been drilled through the fault fracture zones. During these past four years, a similar experiment and research at the Atera fault, of which some parts seem to have been dislocated by the 1586 Tensyo earthquake, has been undertaken. The features of the Atera fault are as follows: (1) total length is about 70 km, (2) general trend is NW45_Kwith a left-lateral strike slip, (3) slip rate is estimated as 3-5 m/1000 yrs. and the average recurrence time as 1700 yrs., (4) seismicity is very low at present, and (5) lithologies around the fault are basically granitic rocks and rhyolite. We have conducted integrated investigations by surface geophysical survey and drilling around the Atera fault. Six boreholes have been drilled from the depth of 400 m to 630 m. Four of these boreholes are located on a line crossing the fracture zone of the Atera fault. Resistivity and gravity structures inferred from surface geophysical surveys were compared with the physical properties

  19. The association of calcaneal spur length and clinical and functional parameters in plantar fasciitis.

    PubMed

    Kuyucu, Ersin; Koçyiğit, Figen; Erdil, Mehmet

    2015-09-01

    Plantar fasciitis (PF)is the most common cause of plantar heel pain. Despite many treatment alternatives for heel spur, the association of calcaneal spur size with clinical and functional parameters is inconclusive. The objective of this study to investigate the correlation of calcaneal spur length with clinical findings and functional status documented with Foot Function Index in patients with plantar fasciitis. We performed power analysis for the sample size estimation. 87 patients with PF were scrutinized to reach the estimated patient number 75. Computer-aided linear measurements were done for spur length from tip to base in milimeters. Perceived pain intensity was evaluated by visual analog scale (VAS). Patients were asked to rate the pain experienced on a 10-cm VAS. Foot function index was applied to the patients to evaluate pain, disability and activity limitation of the patients. Of the 75 participants, 24 were males (32%) and 51 were females (68%). The mean age was 47 ± 10 years (range 30-65 years). The mean calcaneal spur length was 3.86 ± 3.36 mm (range between 0 and 12.2). Calcaneal spur length was significantly correlated with age (p = 0.003), BMI (p = 0.029), symptom duration, (p = 0.001) VAS (p = 0.003), and FFI total score (p < 0.001). Our study demonstrated that length of the calcaneal spur is significantly correlated with age, BMI, symptom duration, perceived pain, FFI pain and disability subscores, and FFI total scores. The size of the calcaneal spur is an important parameter correlated with pain and functional scores in PF. Copyright © 2015 IJS Publishing Group Limited. Published by Elsevier Ltd. All rights reserved.

  20. Experimental Investigation on the Basic Law of the Fracture Spatial Morphology for Water Pressure Blasting in a Drillhole Under True Triaxial Stress

    NASA Astrophysics Data System (ADS)

    Huang, Bingxiang; Li, Pengfeng

    2015-07-01

    The present literature on the morphology of water pressure blasting fractures in drillholes is not sufficient and does not take triaxial confining stress into account. Because the spatial morphology of water pressure blasting fractures in drillholes is not clear, the operations lack an exact basis. Using a large true triaxial water pressure blasting experimental system and an acoustic emission 3-D positioning system, water pressure blasting experiments on cement mortar test blocks (300 mm × 300 mm × 300 mm) were conducted to study the associated basic law of the fracture spatial morphology. The experimental results show that water pressure blasting does not always generate bubble pulsation. After water pressure blasting under true triaxial stress, a crushed compressive zone and a blasting fracture zone are formed from the inside, with the blasting section of the naked drillhole as the center, to the outside. The shape of the outer edges of the two zones is ellipsoidal. The range of the blasting fracture is large in the radial direction of the drillhole, where the surrounding pressure is large, i.e., the range of the blasting fracture in the drillhole radial cross-section is approximately ellipsoidal. The rock near the drillhole wall is affected by a tensile stress wave caused by the test block boundary reflection, resulting in more flake fractures appearing in the fracturing crack surface in the drillhole axial direction and parallel to the boundary surface. The flake fracture is thin, presenting a small-range flake fracture. The spatial morphology of the water pressure blasting fracture in the drillhole along the axial direction is similar to a wide-mouth Chinese bottle: the crack extent is large near the drillhole orifice, gradually narrows inward along the drillhole axial direction, and then increases into an approximate ellipsoid in the internal naked blasting section. Based on the causes of the crack generation, the blasting cracks are divided into three

  1. Effect of Random Natural Fractures on Hydraulic Fracture Propagation Geometry in Fractured Carbonate Rocks

    NASA Astrophysics Data System (ADS)

    Liu, Zhiyuan; Wang, Shijie; Zhao, Haiyang; Wang, Lei; Li, Wei; Geng, Yudi; Tao, Shan; Zhang, Guangqing; Chen, Mian

    2018-02-01

    Natural fractures have a significant influence on the propagation geometry of hydraulic fractures in fractured reservoirs. True triaxial volumetric fracturing experiments, in which random natural fractures are created by placing cement blocks of different dimensions in a cuboid mold and filling the mold with additional cement to create the final test specimen, were used to study the factors that influence the hydraulic fracture propagation geometry. These factors include the presence of natural fractures around the wellbore, the dimension and volumetric density of random natural fractures and the horizontal differential stress. The results show that volumetric fractures preferentially formed when natural fractures occurred around the wellbore, the natural fractures are medium to long and have a volumetric density of 6-9%, and the stress difference is less than 11 MPa. The volumetric fracture geometries are mainly major multi-branch fractures with fracture networks or major multi-branch fractures (2-4 fractures). The angles between the major fractures and the maximum horizontal in situ stress are 30°-45°, and fracture networks are located at the intersections of major multi-branch fractures. Short natural fractures rarely led to the formation of fracture networks. Thus, the interaction between hydraulic fractures and short natural fractures has little engineering significance. The conclusions are important for field applications and for gaining a deeper understanding of the formation process of volumetric fractures.

  2. Proximal femoral fractures.

    PubMed

    Webb, Lawrence X

    2002-01-01

    Fractures of the proximal femur include fractures of the head, neck, intertrochanteric, and subtrochanteric regions. Head fractures commonly accompany dislocations. Neck fractures and intertrochanteric fractures occur with greatest frequency in elderly patients with a low bone mineral density and are produced by low-energy mechanisms. Subtrochanteric fractures occur in a predominantly strong cortical osseous region which is exposed to large compressive stresses. Implants used to address these fractures must be able to accommodate significant loads while the fractures consolidate. Complications secondary to these injuries produce significant morbidity and include infection, nonunion, malunion, decubitus ulcers, fat emboli, deep venous thrombosis, pulmonary embolus, pneumonia, myocardial infarction, stroke, and death.

  3. Evaluation of crack-tip stress fields on microstructural-scale fracture in Al-Al2O3 interpenetrating network composites

    Robert J. Moon; Mark Hoffman; Jurgen Rödel; Shigemi Tochino; Giuseppe Pezzotti

    2009-01-01

    The influence of local microstructure on the fracture process at the crack tip in a ceramic–metal composite was assessed by comparing the measured stress at a microstructural level and analogous finite element modelling (FEM). Fluorescence microprobe spectroscopy was used to investigate the influence of near-crack-tip stress fields on the resulting crack propagation at...

  4. Calcaneal Scoring as an Adjunct to Modified Oxford Hip Scores: Prediction of Contralateral Slipped Capital Femoral Epiphysis.

    PubMed

    Nicholson, Allen D; Huez, Coridon M; Sanders, James O; Liu, Raymond W; Cooperman, Daniel R

    2016-03-01

    In 2 recent studies, modified Oxford hip scores of 16 through 18 have been shown to predict an extremely high risk of contralateral slipping in unilateral slipped capital femoral epiphysis (SCFE). However, the modified Oxford system is not widely used. This may be due, in part, to the complexity of the scoring system, difficulty in viewing all 5 radiographic features on a single x-ray and phenotypic variation in the features. Ossification of the calcaneal apophysis provides an osteologic marker of skeletal maturation in relation to peak height velocity and has been described previously. We examine the value of the calcaneal apophyseal ossification sequence for predicting modified Oxford hip scores. We examined 279 pelvis and matching foot x-rays that were taken at the same session from 94 healthy children aged 3 to 18 years. A fellowship-trained pediatric orthopaedist determined the modified Oxford hip score for each hip radiograph. The calcaneal x-rays had been previously graded. Modified Oxford hip scores were compared with calcaneal scores for each set of matched hip and calcaneal x-rays. Stage 0 to 2 calcanei had 94% of corresponding hip radiographs rated as modified Oxford scores of 16 to 18. Stage 3 calcanei had 54% rated as 16 to 18 and 31% rated as scores 19 to 21. Stage 4 calcanei had 31% rated as scores 19 to 21, and 68% rated as scores 22 to 26. Stage 5 calcanei had 100% rated as 22 to 26. Using data from Popejoy and colleagues' study, the weighted risk of contralateral SCFE was 94% for calcaneal stage 0, 86.5% for calcaneal stage 1, 90.3% for calcaneal stage 2, 55.8% for calcaneal stage 3, 6.1% for calcaneal stage 4, and 0 for calcaneal stage 5. Calcaneal stages 0 to 3 correspond entirely to modified Oxford scores indicating elevated risk of contralateral SCFE. The calcaneal scoring system has potential for adjunctive use with the modified Oxford score for prediction of contralateral SCFE.

  5. Modelling of surface stresses and fracturing during dyke emplacement: Application to the 2009 episode at Harrat Lunayyir, Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Al Shehri, Azizah; Gudmundsson, Agust

    2018-05-01

    Correct interpretation of surface stresses and deformation or displacement during volcanotectonic episodes is of fundamental importance for hazard assessment and dyke-path forecasting. Here we present new general numerical models on the local stresses induced by arrested dykes. In the models, the crustal segments hosting the dyke vary greatly in mechanical properties, from uniform or non-layered (elastic half-spaces) to highly anisotropic (layers with strong contrast in Young's modulus). The shallow parts of active volcanoes and volcanic zones are normally highly anisotropic and some with open contacts. The numerical results show that, for a given surface deformation, non-layered (half-space) models underestimate the dyke overpressure/thickness needed and overestimate the likely depth to the tip of the dyke. Also, as the mechanical contrast between the layers increases, so does the stress dissipation and associated reduction in surface stresses (and associated fracturing). In the absence of open contacts, the distance between the two dyke-induced tensile and shear stress peaks (and fractures, if any) at the surface is roughly twice the depth to the tip of the dyke. The width of a graben, if it forms, should therefore be roughly twice the depth to the tip of the associated arrested dyke. When applied to the 2009 episode at Harrat Lunayyir, the main results are as follows. The entire 3-7 km wide fracture zone/graben formed during the episode is far too wide to have been generated by induced stresses of a single, arrested dyke. The eastern part of the zone/graben may have been generated by the inferred, arrested dyke, but the western zone primarily by regional extensional loading. The dyke tip was arrested at only a few hundred metres below the surface, the estimated thickness of the uppermost part of the dyke being between about 6 and 12 m. For the inferred dyke length (strike dimension) of about 14 km, this yields a dyke length/thickness ratio between 2400 and 1200

  6. Limited sinus tarsi approach for intra-articular calcaneus fractures.

    PubMed

    Kikuchi, Christian; Charlton, Timothy P; Thordarson, David B

    2013-12-01

    Operative treatment of calcaneal fractures has a historically high rate of wound complications, so the most optimal operative approach has been a topic of investigation. This study reviews the radiographic and clinical outcomes of the use of the sinus tarsi approach for operative fixation of these fractures with attention to the rate of infection and restoration of angular measurements. The radiographs and charts of 20 patients with 22 calcaneal fractures were reviewed to assess for restoration of angular and linear dimensions of the calcaneus as well as time to radiographic union. Secondary outcome measures included the rate of postoperative infection, osteomyelitis, revision surgeries, and nonunion. We found a statistically significant restoration of Böhler's angle and calcaneal width. Three of the 22 cases had a superficial wound infection. One patient had revision surgery for symptomatic hardware removal. There were no events of osteomyelitis, deep infection, malunion, or nonunion. We found that the sinus tarsi approach yielded similar outcomes to those reported in the literature. Level IV, retrospective case series.

  7. The effect of concentrated bone marrow aspirate in operative treatment of fifth metatarsal stress fractures; a double-blind randomized controlled trial.

    PubMed

    Weel, Hanneke; Mallee, Wouter H; van Dijk, C Niek; Blankevoort, Leendert; Goedegebuure, Simon; Goslings, J Carel; Kennedy, John G; Kerkhoffs, Gino M M J

    2015-08-20

    Fifth metatarsal (MT-V) stress fractures often exhibit delayed union and are high-risk fractures for non-union. Surgical treatment, currently considered as the gold standard, does not give optimal results, with a mean time to fracture union of 12-18 weeks. In recent studies, the use of bone marrow cells has been introduced to accelerate healing of fractures with union problems. The aim of this randomized trial is to determine if operative treatment of MT-V stress fractures with use of concentrated blood and bone marrow aspirate (cB + cBMA) is more effective than surgery alone. We hypothesize that using cB + cBMA in the operative treatment of MT-V stress fractures will lead to an earlier fracture union. A prospective, double-blind, randomized controlled trial (RCT) will be conducted in an academic medical center in the Netherlands. Ethics approval is received. 50 patients will be randomized to either operative treatment with cB + cBMA, harvested from the iliac crest, or operative treatment without cB + cBMA but with a sham-treatment of the iliac crest. The fracture fixation is the same in both groups, as is the post-operative care.. Follow up will be one year. The primary outcome measure is time to union in weeks on X-ray. Secondary outcome measures are time to resumption of work and sports, functional outcomes (SF-36, FAOS, FAAM), complication rate, composition of osteoprogenitors in cB + cBMA and cost-effectiveness. Furthermore, a bone biopsy is taken from every stress fracture and analysed histologically to determine the stage of the stress fracture. The difference in primary endpoint between the two groups is analysed using student's t-test or equivalent. This trial will likely provide level-I evidence on the effectiveness of cB + cBMA in the operative treatment of MT-V stress fractures. Netherlands Trial Register (reg.nr NTR4377 ).

  8. A retrospective cohort study on the influence of UV index and race/ethnicity on risk of stress and lower limb fractures

    PubMed Central

    2013-01-01

    Background Low vitamin D status increases the risk of stress fractures. As ultraviolet (UV) light is required for vitamin D synthesis, low UV light availability is thought to increase the risk of vitamin D insufficiency and poor bone health. The purpose of this investigation was to determine if individuals with low UV intensity at their home of record (HOR) or those with darker complexions are at increased risk of developing stress fractures and lower limb fractures during U.S. Army Basic Combat Training (BCT). Methods This was a retrospective cohort study using the Armed Forces Health Surveillance Center data repository. All Basic trainees were identified from January 1997 to January 2007. Cases were recruits diagnosed with stress fractures and lower limb fractures during BCT. The recruit’s home of record (HOR) was identified from the Defense Manpower Data Center database. The average annual UV intensity at the recruits’ HOR was determined using a U.S National Weather Service database and recruits were stratified into low (≤3.9); moderate (4.0-5.4), and high (≥5.5) UV index regions. Race was determined from self-reports. Results The dataset had 421,461 men and 90,141women. Compared to men, women had greater risk of developing stress fractures (odds ratio (OR) = 4.5, 95% confidence interval (95%CI) = 4.4-4.7, p < 0.01). Contrary to the hypothesized effect, male and female recruits from low UV index areas had a slightly lower risk of stress fractures (male OR (low UV/high UV) = 0.92, 95%CI = 0.87-0.97; females OR = 0.89, 95%CI = 0.84-0.95, p < 0.01) and were at similar risk for lower limb fractures (male OR = 0.98, 95%CI = 0.89-1.07; female OR = 0.93, 95%CI = 0.80-1.09) than recruits from high UV index areas. Blacks had lower risk of stress and lower limb fractures than non-blacks, and there was no indication that Blacks from low UV areas were at increased risk for bone injuries. Conclusions The UV index at

  9. A retrospective cohort study on the influence of UV index and race/ethnicity on risk of stress and lower limb fractures.

    PubMed

    Montain, Scott J; McGraw, Susan M; Ely, Matthew R; Grier, Tyson L; Knapik, Joseph J

    2013-04-12

    Low vitamin D status increases the risk of stress fractures. As ultraviolet (UV) light is required for vitamin D synthesis, low UV light availability is thought to increase the risk of vitamin D insufficiency and poor bone health. The purpose of this investigation was to determine if individuals with low UV intensity at their home of record (HOR) or those with darker complexions are at increased risk of developing stress fractures and lower limb fractures during U.S. Army Basic Combat Training (BCT). This was a retrospective cohort study using the Armed Forces Health Surveillance Center data repository. All Basic trainees were identified from January 1997 to January 2007. Cases were recruits diagnosed with stress fractures and lower limb fractures during BCT. The recruit's home of record (HOR) was identified from the Defense Manpower Data Center database. The average annual UV intensity at the recruits' HOR was determined using a U.S National Weather Service database and recruits were stratified into low (≤3.9); moderate (4.0-5.4), and high (≥5.5) UV index regions. Race was determined from self-reports. The dataset had 421,461 men and 90,141 women. Compared to men, women had greater risk of developing stress fractures (odds ratio (OR) = 4.5, 95% confidence interval (95%CI) = 4.4-4.7, p < 0.01). Contrary to the hypothesized effect, male and female recruits from low UV index areas had a slightly lower risk of stress fractures (male OR (low UV/high UV) = 0.92, 95%CI = 0.87-0.97; females OR = 0.89, 95%CI = 0.84-0.95, p < 0.01) and were at similar risk for lower limb fractures (male OR = 0.98, 95%CI = 0.89-1.07; female OR = 0.93, 95%CI = 0.80-1.09) than recruits from high UV index areas. Blacks had lower risk of stress and lower limb fractures than non-blacks, and there was no indication that Blacks from low UV areas were at increased risk for bone injuries. The UV index at home of record is not associated with stress

  10. Dual-energy X-ray absorptiometry derived structural geometry for stress fracture prediction in male U.S. Marine Corps recruits.

    PubMed

    Beck, T J; Ruff, C B; Mourtada, F A; Shaffer, R A; Maxwell-Williams, K; Kao, G L; Sartoris, D J; Brodine, S

    1996-05-01

    A total of 626 U.S. male Marine Corps recruits underwent anthropometric measurements and dual-energy X-ray absorptiometry (DXA) scans of the femoral midshaft and the distal third of the tibia prior to a 12 week physical training program. Conventionally obtained frontal plane DXA scan data were used to measure the bone mineral density (BMD) as well as to derive the cross-sectional area, moment of inertia, section modulus, and bone width in the femur, tibia, and fibula. During training, 23 recruits (3.7%) presented with a total of 27 radiologically confirmed stress fractures in various locations in the lower extremity. After excluding 16 cases of shin splints, periostitis, and other stress reactions that did not meet fracture definition criteria, we compared anthropometric and bone structural geometry measurements between fracture cases and the remaining 587 normals. There was no significant difference in age (p = 0.8), femur length (p = 0.2), pelvic width (p = 0.08), and knee width at the femoral condyles (p = 0.06), but fracture cases were shorter (p = 0.01), lighter (p = 0.0006), and smaller in most anthropometric girth dimensions (p < 0.04). Fracture case bone cross-sectional areas (p < 0.001), moments of inertia (p < 0.001), section moduli (p < 0.001), and widths (p < 0.001) as well as BMD (p < 0.03) were significantly smaller in the tibia and femur. After correcting for body weight differences, the tibia cross-sectional area (p = 0.03), section modulus (p = 0.05), and width (p = 0.03) remained significantly smaller in fracture subjects. We conclude that both small body weight and small diaphyseal dimensions relative to body weight are factors predisposing to the development of stress fractures in this population. These results suggest that bone structural geometry measurements derived from DXA data may provide a simple noninvasive methodology for assessing the risk of stress fracture.

  11. Experimental development of low-frequency shear modulus and attenuation measurements in mated rock fractures: Shear mechanics due to asperity contact area changes with normal stress

    DOE PAGES

    Saltiel, Seth; Selvadurai, Paul A.; Bonner, Brian P.; ...

    2017-02-16

    Reservoir core measurements can help guide seismic monitoring of fluid-induced pressure variations in tight fractured reservoirs including those targeted for supercritical CO 2 injection. We present the first seismic-frequency ‘room-dry’ measurements of fracture specific shear stiffness, using artificially fractured standard granite samples with different degrees of mating, a well-mated tensile fracture from a dolomite reservoir core, as well as simple roughened polymethyl methacrylate (PMMA) surfaces. We have adapted a low-frequency (0.01 to 100 Hz) shear modulus and attenuation apparatus to explore the seismic signature of fractures and understand the mechanics of asperity contacts under a range of normal stress conditions.more » Our instrument is unique in its ability to measure at low normal stresses (0.5 – 20 MPa), simulating 'open' fractures in shallow or high fluid pressure reservoirs. The accuracy of our instrument is demonstrated by calibration and comparison to ultrasonic measurements and low-frequency direct shear measurements of intact samples from the literature. Pressure sensitive film was used to measure real contact area of the fracture surfaces. The fractured shear modulus for the majority of the samples shows an exponential dependence on real contact area. A simple numerical model, with one bonded circular asperity, predicts this behavior and matches the data for the simple PMMA surfaces. The rock surfaces reach their intact moduli at lower contact area than the model predicts, likely due to more complex geometry. Lastly, we apply our results to a Linear-Slip Interface Model to estimate reflection coefficients and calculate shear wave time delays due to the lower wave velocities through the fractured zone. We find that cross-well surveys could detect even well-mated hard rock fractures assuming the availability of high repeatability acquisition systems.« less

  12. Experimental development of low-frequency shear modulus and attenuation measurements in mated rock fractures: Shear mechanics due to asperity contact area changes with normal stress

    SciT

    Saltiel, Seth; Selvadurai, Paul A.; Bonner, Brian P.

    Reservoir core measurements can help guide seismic monitoring of fluid-induced pressure variations in tight fractured reservoirs including those targeted for supercritical CO 2 injection. We present the first seismic-frequency ‘room-dry’ measurements of fracture specific shear stiffness, using artificially fractured standard granite samples with different degrees of mating, a well-mated tensile fracture from a dolomite reservoir core, as well as simple roughened polymethyl methacrylate (PMMA) surfaces. We have adapted a low-frequency (0.01 to 100 Hz) shear modulus and attenuation apparatus to explore the seismic signature of fractures and understand the mechanics of asperity contacts under a range of normal stress conditions.more » Our instrument is unique in its ability to measure at low normal stresses (0.5 – 20 MPa), simulating 'open' fractures in shallow or high fluid pressure reservoirs. The accuracy of our instrument is demonstrated by calibration and comparison to ultrasonic measurements and low-frequency direct shear measurements of intact samples from the literature. Pressure sensitive film was used to measure real contact area of the fracture surfaces. The fractured shear modulus for the majority of the samples shows an exponential dependence on real contact area. A simple numerical model, with one bonded circular asperity, predicts this behavior and matches the data for the simple PMMA surfaces. The rock surfaces reach their intact moduli at lower contact area than the model predicts, likely due to more complex geometry. Lastly, we apply our results to a Linear-Slip Interface Model to estimate reflection coefficients and calculate shear wave time delays due to the lower wave velocities through the fractured zone. We find that cross-well surveys could detect even well-mated hard rock fractures assuming the availability of high repeatability acquisition systems.« less

  13. Fatigue Fractures

    PubMed Central

    Morris, James M.

    1968-01-01

    Fatigue (or stress) fracture of bone in military recruits has been recognized for many years. Most often it is a metatarsal bone that is involved but the tarsal bones, calcaneus, tibia, fibula, femur, and pelvis are occasionally affected. Reports of such fractures in the ribs, ulna and vertebral bodies may be found in the literature. In recent years, there has been increasing awareness of the occurrence of fatigue fractures in the civilian population. Weekend sportsmen, athletes in an early phase of training, and persons engaged in unaccustomed, repetitive, vigorous activity are potential victims of such a fracture. The signs and symptoms, roentgenographic findings, treatment and etiology of fatigue fractures are dealt with in this presentation. ImagesFigure 1.Figure 2.Figure 3.Figure 4.Figure 5.Figure 6. PMID:5652745

  14. Fracture toughness, tensile and stress corrosion cracking properties of Alloy 600, Alloy 690 and their welds in water

    SciT

    Brown, C.M.; Mills, W.J.

    1996-10-01

    The fracture toughness and tensile properties of Alloy 600, Alloy 690 and their welds, EN82H and EN52, were characterized in 54 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 mechanical properties. In addition, the stress corrosion cracking (SCC) behavior of EN82H and EN52 welds was evaluated in 360 C water with high hydrogen. Elastic-plastic J{sub c} fracture toughness testing revealed that the fracture resistance of all test materials was exceptionally high in 54 and 338 C air and 338 C water, demonstratingmore » that fracture properties were essentially unaffected by the high temperature water environment. In 54 C water, however, J{sub c} values for EN82H and EN52 welds were reduced by an order of magnitude, and Alloy 690 showed a five-fold decrease in J{sub c}. Tensile properties for all test materials were essentially unaffected by the water environment, except for the total elongation for EN82H welds which was significantly reduced in 54 C water. At a strain rate of 5 x 10{sup 6} sec{sup {minus}1} in low temperature water, there appears to be sufficient time for environmental interactions to restrict ductility in EN82H welds. Constant-load testing of precracked weld specimens in 360 C water resulted in extensive intergranular SCC in EN82H welds loaded to K{sub I} levels between 35 and 55 MPa {radical}m, whereas no SCC occurred in EN52 welds under comparable test conditions.« less

  15. [Tibio-talo-calcaneal arthrodesis by retrograde intramedullary nail--a case report].

    PubMed

    Lipiński, Łukasz; Synder, Marek; Sibiński, Marcin

    2011-01-01

    We described a case of 64 year old overweight women, who was treated with revision tibio-talo-calcaneal artrodesis with the use of retrograde intramedullary nail. The procedure was performed after failed primary arthrodesis with the use of lateral approach and fibula osteotomy. Stabilization with intramedullary nail gave good clinical and functional result with a good bone healing.

  16. A case report of a completely displaced stress fracture of the femoral shaft in a middle-aged male athlete - A precursor of things to come?

    PubMed

    Larsen, Peter; Elsoe, Rasmus; Rathleff, Michael S

    2016-05-01

    Displaced stress fractures of the femoral shaft are very uncommon. The proportion of middle-aged and older age groups participating in long-distance running, triathlon and other high intensity sports is increasing. As a consequence stress fracture of the femoral shaft may be on the rise in the future. The patient was 43 years old male caucasian triathlete. The authors met the patient after he was admitted with a displaced femoral shaft fracture. The fracture occurred during running at the national championship in ½ Ironman. The patient reported that his symptoms had gradually developed over the last month before the fracture with pain localized anterior to the thigh. The patient interpreted the symptoms as local muscle damage. A clinical examination was conducted by a physiotherapist and the symptoms were interpreted as a simple muscle injury in the quadriceps. When presented with a patient with non-traumatic, diffuse anterior thigh pain in an individual of this age, who is participating in high-level endurance running; clinicians should consider the possibility that the cause of the symptoms may be a femoral shaft stress fracture. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Participation in ball sports may represent a prehabilitation strategy to prevent future stress fractures and promote bone health in young athletes.

    PubMed

    Tenforde, Adam Sebastian; Sainani, Kristin Lynn; Carter Sayres, Lauren; Milgrom, Charles; Fredericson, Michael

    2015-02-01

    Sports participation has many benefits for the young athlete, including improved bone health. However, a subset of athletes may attain suboptimal bone health and be at increased risk for stress fractures. This risk is greater for female than for male athletes. In healthy children, high-impact physical activity has been shown to improve bone health during growth and development. We offer our perspective on the importance of promoting high-impact, multidirectional loading activities, including ball sports, as a method of enhancing bone quality and fracture prevention based on collective research. Ball sports have been associated with greater bone mineral density and enhanced bone geometric properties compared with participation in repetitive, low-impact sports such as distance running or nonimpact sports such as swimming. Runners and infantry who participated in ball sports during childhood were at decreased risk of future stress fractures. Gender-specific differences, including the coexistence of female athlete triad, may negate the benefits of previous ball sports on fracture prevention. Ball sports involve multidirectional loading with high ground reaction forces that may result in stiffer and more fracture-resistant bones. Encouraging young athletes to participate in ball sports may optimize bone health in the setting of adequate nutrition and in female athletes, eumenorrhea. Future research to determine timing, frequency, and type of loading activity could result in a primary prevention program for stress fracture injuries and improved life-long bone health. Copyright © 2015 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

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

    PubMed

    Kabilan, Senthil; Jung, Hun Bok; Kuprat, Andrew P; Beck, Anthon N; Varga, Tamas; Fernandez, Carlos A; Um, Wooyong

    2016-06-21

    X-ray microtomography (XMT) imaging combined with three-dimensional (3D) computational fluid dynamics (CFD) modeling technique was used to study the effect of geochemical and geomechanical processes on fracture permeability in composite Portland cement-basalt caprock core samples. The effect of fluid density and viscosity and two different pressure gradient conditions on fracture permeability was numerically studied by using fluids with varying density and viscosity and simulating two different pressure gradient conditions. After the application of geomechanical stress but before CO2-reaction, CFD revealed fluid flow increase, 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 less precipitation in fractures located at the cement-basalt interface. CFD estimated changes in flow profile and differences in absolute values of flow velocity due to different pressure gradients. CFD was able to highlight the profound effect of fluid viscosity on velocity profile and fracture permeability. 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.

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

    SciT

    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

  20. Fatigue-type stress fractures of the lower limb associated with fibrous cortical defects/non-ossifying fibromas in the skeletally immature.

    PubMed

    Shimal, A; Davies, A M; James, S L J; Grimer, R J

    2010-05-01

    To investigate the association of a fatigue-type stress fracture and a fibrous cortical defect/non-ossifying fibroma (FCD/NOF) of the lower limb long bones in skeletally immature patients. The patient database of a specialist orthopaedic oncology centre was searched to determine the number of skeletally immature patients (stress fracture. The diagnosis was established by a combination of typical imaging findings of a fatigue-type stress fracture, the absence of aggressive features suggestive of a sarcoma (e.g., interrupted periosteal reaction, cortical breach, and a soft-tissue mass) together with evidence of consolidation or healing on follow-up radiographs and resolution of symptoms over the subsequent weeks. The database was also used to determine the number of skeletally immature cases (stress fracture and a FCD or NOF) were reviewed. Six percent of patients (five cases) referred to an orthopaedic oncology unit, who were subsequently shown to have a stress fracture of the lower limb long bones, were found to have a related FCD/NOF. All had been referred with a suggested diagnosis of a bone sarcoma and/or osteomyelitis. The possibility of a stress fracture had been raised in only one case. Four cases involved the proximal tibia and one the distal femur. Radiographs revealed that both lesions arose in the posteromedial cortex in all but one of the cases. The radiographs and magnetic resonance imaging (MRI) features were considered typical of the overlapping pathological features of the lesions. A sarcoma could be effectively excluded in the absence of true

  1. Clinical observation of biomimetic mineralized collagen artificial bone putty for bone reconstruction of calcaneus fracture

    PubMed Central

    Pan, Yong-Xiong; Yang, Guang-Gang; Li, Zhong-Wan; Shi, Zhong-Min; Sun, Zhan-Dong

    2018-01-01

    Abstract This study investigated clinical outcomes of biomimetic mineralized collagen artificial bone putty for bone reconstruction in the treatment of calcaneus fracture. Sixty cases of calcaneal fractures surgically treated with open reduction and internal fixation in our hospital from June 2014–2015 were chosen and randomly divided into two groups, including 30 cases treated with biomimetic mineralized collagen artificial bone putty as treatment group, and 30 cases treated with autogenous ilia as control group. The average follow-up time was 17.2 ± 3.0 months. The results showed that the surgery duration and postoperative drainage volume of treatment group were significantly lower than control group; there were no statistically significant differences in the fracture healing time, American Orthopaedic Foot and Ankle Society scores at 3 and 12 months after surgery, Böhler’s angle, Gissane’s angle and height of calcaneus between the two groups. There were no significant differences in wound complication and reject reaction between the two groups, while significant difference in donor site complication. As a conclusion, the implantation of biomimetic mineralized collagen artificial bone putty in the open reduction of calcaneal fracture resulted in reliable effect and less complications, which is suitable for clinical applications in the treatment of bone defect in calcaneal fractures. PMID:29644087

  2. A cross-sectional study of the effects of load carriage on running characteristics and tibial mechanical stress: implications for stress-fracture injuries in women.

    PubMed

    Xu, Chun; Silder, Amy; Zhang, Ju; Reifman, Jaques; Unnikrishnan, Ginu

    2017-03-23

    Load carriage is associated with musculoskeletal injuries, such as stress fractures, during military basic combat training. By investigating the influence of load carriage during exercises on the kinematics and kinetics of the body and on the biomechanical responses of bones, such as the tibia, we can quantify the role of load carriage on bone health. We conducted a cross-sectional study using an integrated musculoskeletal-finite-element model to analyze how the amount of load carriage in women affected the kinematics and kinetics of the body, as well as the tibial mechanical stress during running. We also compared the biomechanics of walking (studied previously) and running under various load-carriage conditions. We observed substantial changes in both hip kinematics and kinetics during running when subjects carried a load. Relative to those observed during running without load, the joint reaction forces at the hip increased by an average of 49.1% body weight when subjects carried a load that was 30% of their body weight (ankle, 4.8%; knee, 20.6%). These results indicate that the hip extensor muscles in women are the main power generators when running with load carriage. When comparing running with walking, finite element analysis revealed that the peak tibial stress during running (tension, 90.6 MPa; compression, 136.2 MPa) was more than three times as great as that during walking (tension, 24.1 MPa; compression, 40.3 MPa), whereas the cumulative stress within one stride did not differ substantially between running (15.2 MPa · s) and walking (13.6 MPa · s). Our findings highlight the critical role of hip extensor muscles and their potential injury in women when running with load carriage. More importantly, our results underscore the need to incorporate the cumulative effect of mechanical stress when evaluating injury risk under various exercise conditions. The results from our study help to elucidate the mechanisms of stress fracture in women.

  3. Concurrent recordings of Electrical Current Emissions and Acoustic Emissions detected from marble specimens subjected to mechanical stress up to fracture

    NASA Astrophysics Data System (ADS)

    Stavrakas, I.; Hloupis, G.; Triantis, D.; Vallianatos, F.

    2012-04-01

    The emission of electrical signals during the application of mechanical stress on brittle geo-materials (the so called Pressure Stimulated Current - PSC[1,2]), provides significant information regarding the mechanical status of the studied rock sample, since PSCs are originated as a result of the opening of cracks and microfractures[3]. The latter mechanism for the creation of PSCs it is straightforward to associated with the recording of acoustic emissions (AE). To justify the common origin of PSCs and AE due to opening of cracks, a combined study was performed implicating the concurrent recording of electric current emissions and AE on marble samples when they are subjected to linearly increasing mechanical load up to the fracture. The electric signal detected is recorded by an ultra sensitive electrometer (Keithley 6514). The sensor used for detecting the electric current is a pair of gold plated electrodes adapted bilaterally on the sample found under axial mechanical stress[4]. The AE were recorded through the Physical Acoustics PCI-2 Acquisition System. The experimental results prove the strong association of the recorded electrical signals and the corresponding acoustic emissions justifying their common origin due to opening of microfractures. Furthermore, when the applied mechanical load exceeds the yield stress then an increasing of PSCs amplitude along with that of AE rate is observed. Acknowledgments. This work was partly supported by the THALES Program of the Ministry of Education of Greece and the European Union in the framework of the project entitled "Integrated understanding of Seismicity, using innovative Methodologies of Fracture mechanics along with Earthquake and non extensive statistical physics - Application to the geodynamic system of the Hellenic Arc. SEISMO FEAR HELLARC".

  4. High Serum 25-hydroxyvitamin D is Associated with Low Incidence of Stress Fractures

    DTIC Science & Technology

    2011-06-01

    hypocalcemia , and is essential for bone formation and resorption (1-4). Adequate serum concentration of 25-hydroxyvitamin D (25(OH)D) is associated with...nutritional status, since it includes the effects of solar ultraviolet (UVB) exposure and oral intake from food and supplements, and it has a markedly...subjects may not have been high enough for a protective effect on fractures to occur. Previous research has shown that amenorrhea and history of

  5. Bone Geometry as a Predictor of Tissue Fragility and Stress Fracture Risk

    DTIC Science & Technology

    2006-10-01

    WidthML/2) directions. Moment of inertia and section modulus were assessed because these geometric measures are related to the bending and...mandible: Thomas; 1963. Ferretti JL, Capozza RF, Mondelo N, Zanchetta JR. Interrelationships between densitometric, geometric , and mechanical...fractures. Am J Sports Med, 28:245-251, 2000. Miller GJ, Purkey WW, Jr. The geometric properties of paired human tibiae. J Biomech, 13:1-8, 1980

  6. The effects of age, physical activity level, and body anthropometry on calcaneal speed of sound value in men.

    PubMed

    Chin, Kok-Yong; Soelaiman, Ima-Nirwana; Mohamed, Isa Naina; Ibrahim, Suraya; Wan Ngah, Wan Zurinah

    2012-01-01

    The influences of age, physical activity, and body anthropometry on calcaneal speed of sound are different among young adults, middle-aged, and elderly men. Quantitative ultrasound assessment of bone health status is much needed for developing countries in the screening of osteoporosis, but further studies on the factors that influence the quantitative ultrasound indices are required. The present study examined the influence of age, lifestyle factors, and body anthropometry on calcaneal speed of sound (SOS) in a group of Malaysian men of diverse age range. A cross-sectional study was conducted, and data from 687 eligible males were used for analysis. They answered a detailed questionnaire on their physical activity status, and their anthropometric measurements were taken. Their calcaneal SOS values were evaluated using the CM-200 sonometer (Furuno, Nishinomiya City, Japan). Subjects with higher body mass index (BMI) had higher calcaneal SOS values albeit significant difference was only found in the elderly subjects (p < 0.05). Sedentary subjects had lower calcaneal SOS values than physically active subjects, but significant difference was only found in the middle-aged subjects (p < 0.05). Calcaneal SOS was significantly (p < 0.05) correlated with age in young men; height, BMI, and physical activity score in middle-aged men; height and physical activity score in elderly men; and age and physical activity score for overall subjects. In a multivariate regression model, significant (p < 0.05) predictors for calcaneal SOS included age for young men; physical activity, BMI, body fat percentage, and height for middle-aged men; height for elderly men; and age, height, physical activity, weight, and body fat percentage for overall subjects. Age, body anthropometry, and physical activity level have significant effects on the calcaneal SOS value in men.

  7. Evidence for initiation of frictional partial slip as the mechanism behind nonlinear stress-strain hysteresis in rock fractures under seismic-frequency torsion

    NASA Astrophysics Data System (ADS)

    Saltiel, S.; Bonner, B. P.; Delbridge, B. G.; Ajo Franklin, J. B.

    2016-12-01

    We have adapted a low-frequency (0.1 - 64 Hz) torsional apparatus to explore the pure shear behavior of rock fractures under low normal stresses, simulating low effective stress environments - shallow depths and/or under high pore pressures. The instrument is unique in this ability to measure under very low confinement as well as to probe partial slip on the outside of asperities, before full slip nucleation occurs. Using a sinusoidal oscillation around this condition, we can probe the stress-strain constitutive relation at a range of strain amplitudes and the rate-dependence of the initiation of asperity slip. We find different, nonlinear, stress-strain constitutive relations for dolomite, rhyolite, and granite fractured samples, but all show softening at high strain amplitudes (above microstrain or micron-scale displacement). All measured samples exhibit qualitatively similar time-series hysteresis loops and frequency-dependence. The low frequency stress-strain loops stiffen at the high strain static end of the sinusoidal oscillation. This shape is determined by harmonic generation in the strain, while the stress signal has low power in harmonics, confirming that the driver and electronics are not the source of this nonlinearity. We also observe that this stiffening cusp does not occur as frequency increases above 8 Hz (opposite to normal dispersion seen at higher normal stresses). We monitor the fracture surface wear with repeated cycles to show the extent of slip on mapped asperities. These observations suggest that a rate dependent, healing, process causes the nonlinear responce of fracture faces under low normal stress to periodic shear. We propose that static friction at the low strain-rate part of the cycle, when given enough time at low oscillation frequencies, causes this stiffening cusp shape in the hysteretic stress-strain curve. An analytic model with idealized contact area is used to constrain the rate-state friction constitutive model parameters

  8. Fault interaction and stresses along broad oceanic transform zone: Tjörnes Fracture Zone, north Iceland

    NASA Astrophysics Data System (ADS)

    Homberg, C.; Bergerat, F.; Angelier, J.; Garcia, S.

    2010-02-01

    Transform motion along oceanic transforms generally occurs along narrow faults zones. Another class of oceanic transforms exists where the plate boundary is quite large (˜100 km) and includes several subparallel faults. Using a 2-D numerical modeling, we simulate the slip distribution and the crustal stress field geometry within such broad oceanic transforms (BOTs). We examine the possible configurations and evolution of such BOTs, where the plate boundary includes one, two, or three faults. Our experiments show that at any time during the development of the plate boundary, the plate motion is not distributed along each of the plate boundary faults but mainly occurs along a single master fault. The finite width of a BOT results from slip transfer through time with locking of early faults, not from a permanent distribution of deformation over a wide area. Because of fault interaction, the stress field geometry within the BOTs is more complex than that along classical oceanic transforms and includes stress deflections close to but also away from the major faults. Application of this modeling to the 100 km wide Tjörnes Fracture Zone (TFZ) in North Iceland, a major BOT of the Mid-Atlantic Ridge that includes three main faults, suggests that the Dalvik Fault and the Husavik-Flatey Fault developed first, the Grismsey Fault being the latest active structure. Since initiation of the TFZ, the Husavik-Flatey Fault accommodated most of the plate motion and probably persists until now as the main plate structure.

  9. Analysis of stress-strain, fracture, and ductility behavior of aluminum maxtrix composites containing discontinuous silicon carbide reinforcement

    NASA Technical Reports Server (NTRS)

    Mcdanels, D. L.

    1985-01-01

    Mechanical properties and stress-strain behavior were evaluated for several types of commercially fabricated aluminum matrix composites, containing up to 40 vol pct discontinuous SiC whisker, nodule, or particulate reinforcement. The elastic modulus of the composites was found to be isotropic, to be independent of type of reinforcement, and to be controlled solely by the volume percentage of SiC reinforcement present. The yield/tensile strengths and ductility were controlled primarily by the matrix alloy and temper condition. Type and orientation of reinforcement had some effect on the strengths of composites, but only for those in which the whisker reinforcement was highly oriented. Ductility decreased with increasing reinforcement content; however, the fracture strains observed were higher than those reported in the literature for this type of composite. This increase in fracture strain was probably attributable to cleaner matrix powder, better mixing, and increased mechanical working during fabrication. Comparison of properties with conventional aluminum and titanium structural alloys showed that the properties of the low-cost, lightweight composites demonstrated very good potential for application to aerospace structures.

  10. The nature of fracturing and stress distribution in quartzite around the 1128-M (3700-FT) level of the crescent mine, Coeur d'Alene mining district, Idaho

    Miller, C.H.; Skinner, E.H.

    1980-01-01

    Silver and copper are the principal ores mined from the quartzite at the Crescent mine. Both the main ore-bearing veins and foliation in the quartzite are parallel to the nearly vertical formational contacts. Anisotropy of the quartzite is indicated by both dynamic and static tests. Disking and breakage of core from holes perpendicular to the foliation are about twice what they are in core from holes parallel to foliation. Natural cleavage as well as slabbing and blasting fractures around the tunnels are also controlled by the foliation. Extensive overcore deformation measurements indicate that most of the influence of the tunnels on the "free" stress field is between the rib and a depth of 2.7 m (1 tunnel diameter). The maximum principal stress axis in the free field is nearly horizontal; its magnitude is not much greater than the vertical component and calculations indicate a nearly hydrostatic free stress field. Stress considerably greater than the free field was measured between about 0.3-2.7 m behind the rib and is caused by a transfer of load from above the tunnel opening. Peak stress is in the vertical direction and about 1.7 m behind the rib. An air-injection survey shows that high permeabilities are confined to the highly fractured annulus around a tunnel to a depth of at least 0.6 m. Air-injection measurements could be taken in the interval of about 0.6-1.8 m, but more fractures with high permeabilities may also be present in the annulus from about 0.6-1.2 m. Permeabilities measured deeper than about 1.8 m by the air-injection technique are either very low or nonexistent. The absence of open and noncontinuous fractures beyond about 1.8 m is also indicated by very low porosities and permeabilities of core, very high stresses (which presumably would close fractures), the lack of stains or secondary fillings in disking fractures, a conspicuous lack of ground water in the tunnels, and the fact that fractures encountered in an experimental 0.9-m tunnel did not

  11. Association of stressful life events with accelerated bone loss in older men: the Osteoporotic Fractures in Men (MrOS) Study

    PubMed Central

    Fink, Howard A.; Kuskowski, Michael A.; Cauley, Jane A.; Taylor, Brent C.; Schousboe, John T.; Cawthon, Peggy M.; Ensrud, Kristine E.

    2015-01-01

    Purpose/Introduction Prior studies suggest that stressful life events may increase adverse health outcomes, including falls and possibly fractures. The current study builds on these findings and examines whether stressful life events are associated with increased bone loss. Methods 4388 men aged ≥65 years in the O