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Sample records for compression plate fixation

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

    PubMed

    Hernigou, Philippe; Pariat, Jacques

    2016-12-30

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

  2. Biomechanical comparison of straight and helical compression plates for fixation of transverse and oblique bone fractures: Modeling and experiments.

    PubMed

    Sezek, Sinan; Aksakal, Bunyamin; Gürger, Murat; Malkoc, Melih; Say, Y

    2016-08-12

    Total deformation and stability of straight and helical compression plates were studied by means of the finite element method (FEM) and in vitro biomechanical experiments. Fixations of transverse (TF) and oblique (45°) bone (OF) fractures have been analyzed on sheep tibias by designing the straight compression (SP) and Helical Compression Plate (HP) models. The effects of axial compression, bending and torsion loads on both plating systems were analyzed in terms of total displacements. Numerical models and experimental models suggested that under compression loadings, bone fracture gap closures for both fracture types were found to be in the favor of helical plate designs. The helical plate (HP) fixations provided maximum torsional resistance compared to the (SP) fixations. The fracture gap closure and stability of helical plate fixation for transverse fractures was determined to be higher than that found for the oblique fractures. The comparison of average compression stress, bending and torsion moments showed that the FEM and experimental results are in good agreement and such designs are likely to have a positive impact in future bone fracture fixation designs.

  3. Surgical Outcomes of Biologic Fixation for Subtrochanteric Fracture Using Locking Compression Plates

    PubMed Central

    Jang, Jae Hoon; Ahn, Jae Min; Lee, Hee Jin

    2017-01-01

    Purpose This study aimed to evaluate the surgical outcomes of biologic plating using locking compression plate-distal femur (LCP-DF) in patients with subtrochanteric fracture of the femur. Materials and Methods Between January 2010 and December 2013, 28 consecutive patients with subtrochanteric fractures of the femur, treated with biologic fixation using LCP-DF, were enrolled. Preoperative values, including patient age, sex, body mass index, fracture type, type of lung injury, and surgical timing from injury to surgery, were retrospectively evaluated. Radiologic assessments included time to union, coronal alignment, rotational alignment, and complications such as implant breakage and screw breakage. Adverse events, including postoperative fat embolism and adult respiratory distress syndrome, infection during the follow-up period, and walking ability at the last follow-up visit, were assessed. Results Union was achieved in 27 patients (96.4%) after a mean duration of 5.4 months (range, 3-14 months). No patients developed fat embolism or adult respiratory distress syndrome during the hospitalization period of this study. Conclusion Biologic fixation using locking compression plates may represent a safe surgical option which can be utilized in patients with subtrochanteric fracture regardless of injury severity, surgical timing, fracture type, and presence of lung injury. PMID:28316965

  4. A biomechanical comparison of conventional versus an anatomic plate and compression bolts for fixation of intra-articular calcaneal fractures.

    PubMed

    Wang, Haili; Yang, Zhaoxu; Wu, Zhanpo; Chen, Wei; Zhang, Qi; Li, Ming; Li, Zhiyong; Zhang, Yingze

    2012-08-01

    The purpose of this study was to compare the biomechanical stability obtained by using our technique featured an anatomical plate and compression bolts versus that of the conventional anatomic plate and cancellous screws in the fixation of intraarticular calcaneal fractures. Eighteen fresh frozen lower limbs of cadavers were used to create a reproductive Sanders type-III calcaneal fracture model by using osteotomy. The calcaneus fractures were randomly selected to be fixed either using our anatomical plate and compression bolts or conventional anatomic plate and cancellous screws. Reduction of fracture was evaluated through X radiographs. Each calcaneus was successively loaded at a frequency of 1 Hz for 1000 cycles through the talus using an increasing axial force 20 N to 200 N and 20 N to 700 N, representing the partial weight bearing and full weight bearing, respectively, and then the specimens were loaded to failure. Data extracted from the mechanical testing machine were recorded and used to test for difference in the results with the Wilcoxon signed rank test. No significant difference was found between our fixation technique and conventional technique in displacement during 20-200 N cyclic loading (P=0.06), while the anatomical plate and compression bolts showed a great lower irreversible deformation during 20-700 N cyclic loading (P=0.008). The load achieved at loss of fixation of the constructs for the two groups had significant difference: anatomic plate and compression bolts at 3839.6±152.4 N and anatomic plate and cancellous screws at 3087.3±58.9 N (P=0.008). There was no significant difference between the ultimate displacements. Our technique featured anatomical plate and compression bolts for calcaneus fracture fixation was demonstrated to provide biomechanical stability as good as or better than the conventional anatomic plate and cancellous screws under the axial loading. The study supports the mechanical viability of using our plate and

  5. Fixation of Intertrochanteric Fractures: Dynamic Hip Screw versus Locking Compression Plate

    PubMed Central

    Mardani-Kivi, Mohsen; Mirbolook, Ahmadreza; Khajeh Jahromi, Sina; Rouhi Rad, Melina

    2013-01-01

    Background According to the existing literature, the Dynamic Hip Screw (DHS) is the preferred standard for the treatment of intertrochanteric fractures. However, some surgeons use other devices such as the Locking Compression Plate (LCP). Objectives In this study, we compared the outcome of using DHS or LCP in intertrochanteric fractures. Materials and Methods This cross-sectional study was carried out on 104 patients who were referred to Pursina Hospital in Rasht, Iran with intertrochanteric fractures of the femur treated with either the DHS or LCP devices. Demographic features, existence or nonexistence of stability and operating time were obtained from questionnaires. During a 6-month follow-up after surgery, patients were interviewed to record variables such as Harris Hip Scores and complications. The patients were also interviewed on their final visit (between 9 and 31 postoperative months). The collected data was analyzed using SPSS. Results We discovered that the number of incidences of limb shortening and device failure was higher for patients treated with the LCP device (P = 0.048 and P = 0.014). Patients treated with the DHS device had higher Harris Hip scores for both the 6-month postoperative and the final evaluation visits (P = 0.01 and P = 0.018). Conclusions Despite the complications of fixation with the DHS device, it remains the most successful for treatment of intertrochanteric fractures. PMID:24350155

  6. Treatment of Unstable Posterior Pelvic Ring Fracture with Pedicle Screw-Rod Fixator Versus Locking Compression Plate: A Comparative Study

    PubMed Central

    Bi, Chun; Wang, Qiugen; Nagelli, Christopher; Wu, Jianhong; Wang, Qian; Wang, Jiandong

    2016-01-01

    Background The aim of this study was to assess the clinical results of treatment for unstable posterior pelvic fractures using a pedicle screw-rod fixator compared to use of a locking compression plate. Material/Methods A retrospective study was performed between June 2010 and May 2014 and the data were collected from 46 patients with unstable posterior pelvic ring fractures. All patients were treated using either a pedicle screw-rod fixator (study group, 24 patients) or locking compression plate (control group, 22 patients). In these patients, causes of injury included traffic accidents (n=27), fall from height (n=12), and crushing accidents (n=7). The quality of reduction and radiological grading were assessed. Clinical assessments included the operation time, times of X-ray exposures, bleeding volume during operation, incision length, and Majeed postoperative functional evaluation. Results No iatrogenic neurovascular injuries occurred during the operations in these 2 groups. The average follow-up time was 24.5 months. All fractures were healed. The significant differences (P<0.05) between the 2 groups were operation duration, size of incision, and intraoperative bleeding volume. Statistically significant differences in the Majeed postoperative functional evaluation and times of X-ray exposures were not found between the 2 groups. Conclusions Similar clinical effects were achieved in treating the posterior pelvic ring fractures using the pedicle screw-rod fixator and the locking compression plate. However, the pedicle screw-rod fixator has the advantages of smaller incision, shorter duration of the operation, and less bleeding volume compared to using the locking compression plate. PMID:27748355

  7. Use of a locking compression plate as an external fixator for repair of a tarsometatarsal fracture in a bald eagle (Haliaeetus leucocephalus).

    PubMed

    Montgomery, Ronald D; Crandall, Elizabeth; Bellah, Jamie R

    2011-06-01

    We describe the successful treatment of a tarsometatarsal fracture in a mature bald eagle (Haliaeetus leucocephalus) using a locking compression plate as an external fixator. The anatomy of the area (inelastic dermis and minimal subcutaneous space) and the high forces placed on a fracture at that site necessitated a unique approach to fixation. The unconventional use of a locking compression plate as an external fixator was minimally invasive, well tolerated by the eagle, and provided adequate stability in opposing fracture forces. This technique may serve as a method of fixation for tarsometatarsal fractures in other large avian species.

  8. Mechanical Comparison of Headless Screw Fixation and Locking Plate Fixation for Talar Neck Fractures.

    PubMed

    Karakasli, Ahmet; Hapa, Onur; Erduran, Mehmet; Dincer, Cemal; Cecen, Berivan; Havitcioglu, Hasan

    2015-01-01

    For talar neck fractures, open reduction and internal fixation have been thought to facilitate revascularization and prevent osteonecrosis. Newer screw systems allow for placement of cannulated headless screws, which provide compression by virtue of a variable pitch thread. The present study compared the biomechanical fixation strength of cannulated headless variable-pitch screw fixation and locking plate fixation. A reproducible talar neck fracture was created in 14 fresh cadaver talar necks. Talar head fixation was then performed using 2 cannulated headless variable-pitch 4-mm/5-mm diameter (4/5) screws (Acutrak; Acumed, Hillsboro, OR) and locking plate fixation. Headless variable-pitch screw fixation had lower failure displacement than did locking plate fixation. No statistically significant differences were found in failure stiffness, yield stiffness (p = .655), yield load (p = .142), or ultimate load between the 2 fixation techniques. Cannulated headless variable-pitch screw fixation resulted in better failure displacement than locking plate fixation in a cadaveric talus model and could be considered a viable option for talus fracture fixation. Headless, fully threaded, variable-pitch screw fixation has inherent advantages compared with locking plate fixation, because it might cause less damage to the articular surface and can compress the fracture for improved reduction. Additionally, plate fixation can increase the risk of avascular necrosis owing to the wider incision and dissection of soft tissues.

  9. Simulation-based particle swarm optimization and mechanical validation of screw position and number for the fixation stability of a femoral locking compression plate.

    PubMed

    Lee, Chian-Her; Shih, Kao-Shang; Hsu, Ching-Chi; Cho, Tomas

    2014-01-01

    Locking compression plates (LCPs) have been used to fix femoral shaft fractures. Previous studies have attempted to identify the best LCP screw positions and numbers to achieve the fixation stability. However, the determined screw positions and numbers were mainly based on the surgeons' experiences. The aim of this study was to discover the best number and positions of LCP screws to achieve acceptable fixation stability. Three-dimensional numerical models of a fractured femur with the LCP were first developed. Then, the best screw position and number of LCPs were determined by using a simulation-based particle swarm optimization algorithm. Finally, the results of the numerical study were validated by conducting biomechanical tests. The results showed that the LCP with six locking screws resulted in the necessary fixation stability, and the best combination of positions of locking screws inserted into the LCP was 1-5-6-7-8-12 (three locking screws on either side of the bone fragment with two locking screws as close as practicable to the fracture site). In addition, the numerical models and algorithms developed in this study were validated by the biomechanical tests. Both the numerical and experimental results can provide clinical suggestions to surgeons and help them to understand the biomechanics of LCP systems.

  10. Mini-plate fixation versus suture suspensory fixation in cervical laminoplasty

    PubMed Central

    Liu, Feng-Yu; Ma, Lei; Huo, Li-Shuang; Cao, Yan-Xiang; Yang, Da-Long; Wang, Hui; Yang, Si-Dong; Ding, Wen-Yuan

    2017-01-01

    Abstract Background: Both the mini-plate fixation and suture suspensory fixation techniques are extensively applied in cervical laminoplasty, but which technique is superior has not been ascertained. The purpose of this meta-analysis is to compare the results between mini-plate fixation and suture suspensory fixation in cervical laminoplasty for the patients with multilevel cervical compressive myelopathy. Methods: PubMed, Embase, the Cochrane library, CNKI, and WANFANG were searched for studies that compared mini-plate fixation and suture suspensory fixation in cervical laminoplasty up to November 1, 2016. We calculated odds ratio (OR) with 95% confidence interval (CI) for dichotomous outcomes and mean difference (MD) with 95% CI for continuous outcomes. Review Manager 5.3 was used for the statistical analyses. Results: A total of 25 studies, involving 1603 participants, were included in this review. The results of this meta-analysis indicated that there were statistically significant differences in postoperative Japanese Orthopedic Association (JOA) scores (MD = 0.67, 95% CI: 0.34–0.99, P < 0.001), JOA scores improvement rate (MD = 4.00, 95% CI: 2.51–5.50, P < 0.001), postoperative Visual Analogue Score (VAS) (MD = −0.81, 95% CI: −1.36 to −0.26, P = 0.004), postoperative range of motion (ROM) (MD = 4.15, 95% CI: 2.06–6.23, P < 0.001), postoperative cervical lordosis (MD = 3.1, 95% CI: 2.02–4.18, P < 0.001), postoperative anteroposterior diameter of the spinal canal (MD = 1.53, 95% CI: 0.11–2.95, P = 0.03), postoperative open angle (MD = 1.93, 95% CI: 0.14–3.71, P = 0.03), postoperative cross-sectional area of the spinal canal (MD = 37.10, 95% CI: 26.92–47.29, P < 0.001), axial symptoms (OR = 0.28, 95% CI: 0.20–0.37, P < 0.001), operation time (MD = 4.46, 95% CI: 0.74–8.19, P = 0.02), and blood loss (MD = 9.24, 95% CI: 6.86–11.62, P < 0.001). However

  11. Unicortical versus bicortical locked plate fixation in midshaft clavicle fractures.

    PubMed

    Bravman, Jonathan T; Taylor, Michal L; Baldini, Todd; Vidal, Armando F

    2015-05-01

    Higher rates of poor outcomes in displaced midshaft clavicle fractures treated nonoperatively have recently been reported. Along with expanding indications for operative fixation and increasing application of locked plate constructs, it is unknown whether complications related to bicortical penetration of the clavicle can be avoided using unicortical fixation. The purpose of this study is to compare the biomechanical properties of unicortical and bicortical fixation in precontoured vs manually contoured locking clavicle plates. Forty-eight Sawbone composite human clavicle specimens (item #3408; Pacific Research Laboratories, Vashon, Washington) with a midshaft clavicle osteotomy were reduced and plated in 8 specimens each using a bicortical and unicortical fixation for each of 3 locked plate constructs (3.5-mm LCP Reconstruction Plate; 3.5-mm LCP Superior Clavicle Plate; 3.5-mm LCP Superior Anterior Clavicle Plate; Synthes, Inc, West Chester, Pennsylvania). Specimens were tested for stiffness in axial torsion and cantilever bending and then loaded to failure in 3-point bending. Data were analyzed using 2-way analysis of variance and Tukey's test (P<.05). No significant differences were found between unicortical and bicortical fixation in failure load, cantilever bending, and cross body stiffness. Bicortical fixation was significantly stiffer than unicortical fixation in torsion only for the same plates. Significant differences also existed between plates in torsion. Unicortical locked plate fixation may be a reasonable option in the treatment of displaced midshaft clavicle fracture fixation to avoid complications associated with posteroinferior hardware penetration following clavicle fracture fixation based on the biomechanical performance of these constructs. However, it remains unclear whether these differences will be clinically significant.

  12. New concepts for bone fracture treatment and the Locking Compression Plate.

    PubMed

    Wagner, Michael; Frenk, Andre; Frigg, Röbi

    2004-01-01

    The operative treatment of bone fractures using plates and screws is a standard successful technique. Internal fixation with plates and screws leads to additional trauma and disturbance of the bone blood supply, which increases the risk of delayed union and infection. However, problems also are encountered in the fixation of osteoporotic bone. The locked internal fixator technique is an approach to optimize internal fixation. It aims at flexible elastic fixation to imitate spontaneous healing, including induction of callus formation. The technology supports what is currently called "minimally invasive plate osteosynthesis" (MIPO), which provides priority to biology over mechanics. An implant system called "Locking Compression Plate (LCP)" was developed, based on many years of experience with compression plating and good clinical results obtained with internal fixators, such as the Less Invasive Stabilization Systems (LISS). It combines the two treatment methods (ie, the compression plating and locked internal fixation methods) into one system. This chapter describes the basic principles of locked internal fixators and some clinical results with the LISS and LCP systems to illustrate the potential of these new systems.

  13. Operative Cost Comparison: Plating Versus Intramedullary Fixation for Clavicle Fractures.

    PubMed

    Hanselman, Andrew E; Murphy, Timothy R; Bal, George K; McDonough, E Barry

    2016-09-01

    Although clavicle fractures often heal well with nonoperative management, current literature has shown improved outcomes with operative intervention for specific fracture patterns in specific patient types. The 2 most common methods of midshaft clavicle fracture fixation are intramedullary and plate devices. Through retrospective analysis, this study performed a direct cost comparison of these 2 types of fixation at a single institution over a 5-year period. Outcome measures included operative costs for initial surgery and any hardware removal surgeries. This study reviewed 154 patients (157 fractures), and of these, 99 had intramedullary fixation and 58 had plate fixation. A total of 80% (79 of 99) of intramedullary devices and 3% (2 of 58) of plates were removed. Average cost for initial intramedullary placement was $2955 (US dollars) less than that for initial plate placement (P<.001); average cost for removal was $1874 less than that for plate removal surgery (P=.2). Average total cost for all intramedullary surgeries was $1392 less than the average cost for all plating surgeries (P<.001). Average cost for all intramedullary surgeries requiring plate placement and removal was $653 less than the average cost for all plating surgeries that involved only placement (P=.04). Intramedullary fixation of clavicle fractures resulted in a statistically significant cost reduction compared with plate fixation, despite the incidence of more frequent removal surgeries. [Orthopedics.2016; 39(5):e877-e882.].

  14. Biomechanics and biology of plate fixation of distal radius fractures.

    PubMed

    Freeland, Alan E; Luber, Kurre T

    2005-08-01

    The fracture management principles of anatomic or near anatomic reduction, fracture stabilization, minimal operative trauma, and early joint motion are paramount in man-aging unstable distal radial fractures. The operative approach and plate selection should correlate with the fracture configuration. Plates have the advantages of providing secure fixation throughout the entire healing process without protruding wires or pins and allowing early and intensive forearm, wrist, and digital exercises. Disadvantages include additional operative trauma, including fragment devascularization; some additional risk of wrist stiffness; occasional tendon rupture; and at times, the need for plate removal. New developments in plate and screw design and operative strategies, fragment specific fixation, and plate strength have improved results with plate fixation. Fixed angle blades and locking screws and pegs enhance overall plate stability, support the articular surface of the distal radius, and are effective in fractures occurring in osteopenic bone.

  15. Comparison of the effect on bone healing process of different implants used in minimally invasive plate osteosynthesis: limited contact dynamic compression plate versus locking compression plate

    PubMed Central

    Xue, Zichao; Xu, Haitao; Ding, Haoliang; Qin, Hui; An, Zhiquan

    2016-01-01

    Minimally invasive plate osteosynthesis (MIPO) has been widely accepted because of its satisfactory clinical outcomes. However, the implant construct that works best for MIPO remains controversial. Different plate designs result in different influence mechanisms to blood flow. In this study, we created ulnar fractures in 42 beagle dogs and fixed the fractures using MIPO. The dogs were randomly divided into two groups and were fixed with a limited contact dynamic compression plate (LC-DCP) or a locking compression plate (LCP). Our study showed that with MIPO, there was no significant difference between the LCP and the LC-DCP in terms of fracture fixation, bone formation, or mineralization. Combined with the previous literature, we inferred that the healing process is affected by the quality of fracture reduction more than plate selection. PMID:27885262

  16. Assessment of carbon fibre composite fracture fixation plate using finite element analysis.

    PubMed

    Saidpour, Seyed H

    2006-07-01

    In the internal fixation of fractured bone by means of bone-plates fastened to the bone on its tensile surface, an on-going concern has been the excessive stress shielding of the bone by the excessively-stiff stainless-steel plate. The compressive stress shielding at the fracture-interface immediately after fracture-fixation delays callus formation and bone healing. Likewise, the tensile stress shielding in the layer of bone underneath the plate can cause osteoporosis and decrease in tensile strength of this layer. In this study a novel forearm internal fracture fixation plate made from short carbon fibre reinforced plastic (CFRP) was used in an attempt to address the problem. Accordingly, it has been possible to analyse the stress distribution in the composite plates using finite-element modelling. A three-dimensional, quarter-symmetric finite element model was generated for the plate system. The stress state in the underlying bone was examined for several loading conditions. Based on the analytical results the composite plate system is likely to reduce stress-shielding effects at the fracture site when subjected to bending and torsional loads. The design of the plate was further optimised by reducing the width around the innermost holes.

  17. Static and Dynamic Differences in Fixation Stability between a Spacer Plate and a Small Stature Plate Fixator Used for High Tibial Osteotomies: A Biomechanical Bone Composite Study

    PubMed Central

    Maas, Stefan; Dueck, Klaus; Pape, Dietrich

    2013-01-01

    Background. The objective of the present study was to compare mechanical strength and stability of the newly designed spacer plate with the gold standard plate for the treatment of medial knee joint osteoarthritis. Materials and Methods. Ten fourth-generation tibial bone composites underwent a medial open-wedge high tibial osteotomy (HTO) according to standard techniques, using five TomoFix plates and five Contour Lock plates. Static compression load to failure and load-controlled cyclical fatigue failure tests were performed. Forces and horizontal displacements were measured; plastic deformations and dynamic stiffness were determined. Results and Discussion. In all samples, rotation of the tibial head and fracture of the opposite cortex were observed. Behaviors of the specimens under static loading were comparable between groups. Cyclic testing revealed lateral significant higher stiffness until failure for the Contour Lock compared to the TomoFix plate. No visible implant failure was observed in any group. Conclusion. Considering the static analysis, both plates offered sufficient stability under physiologic loads of up to 3000 N. The Contour Lock plate-fixated specimens showed a higher stability during the cyclic testing, supposedly due to the wider distance between the fixation screws. PMID:24959357

  18. TIBIOTARSAL COMPRESSION ARTHRODESIS USING A LATERAL LOCKING PLATE

    PubMed Central

    Coughlin, Michael J.; Nery, Caio; Baumfeld, Daniel; Jastifer, James

    2015-01-01

    Objectives: Tibiotalar (TT) arthrodesis is still a very important option in the treatment of primary or post-traumatic arthritis of the ankle but persists the controversy regarding the optimal method for the fixation of the arthrodesis site. No matter the implant used, the goal is to obtain a solid, healthy, pain-free fusion. The purpose of the current study is to present the preliminary results of a novel laterally based tibiotalar compression arthrodesis system using a locked plate. Methods: Thirteen consecutive patients with tibiotalar arthritis were submitted to an arthrodesis using a new lateral plating system. The average age was 59.7 years (range 36~72); nine patients were male and four female. Using a cutting guide, the remaining articular surfaces of the tibia and talus were removed. A compression device was applied to avoid malalignment of the ankle and a precontoured lateral locking plate was used to achieve the joint fusion. Results: Both the AOFAS ankle-hindfoot score and the VAS score improved with the surgery. All patients’ ankles fused by 6 months. In all patients we found a very good alignment in the sagittal, coronal and transverse planes. Conclusion: We believe that a combination of a bilateral compression, contoured bony cuts, and lateral locked plating offers a novel, accurate and useful technique for ankle arthrodesis. PMID:27047874

  19. Biomechanics of bone-fracture fixation by stiffness-graded plates in comparison with stainless-steel plates

    PubMed Central

    Ganesh, VK; Ramakrishna, K; Ghista, Dhanjoo N

    2005-01-01

    Background In the internal fixation of fractured bone by means of bone-plates fastened to the bone on its tensile surface, an on-going concern has been the excessive stress-shielding of the bone by the excessively-stiff stainless-steel plate. The compressive stress-shielding at the fracture-interface immediately after fracture-fixation delays callus formation and bone healing. Likewise, the tensile stress-shielding of the layer of the bone underneath the plate can cause osteoporosis and decrease in tensile strength of this layer. Method In order to address this problem, we propose to use stiffness-graded plates. Accordingly, we have computed (by finite-element analysis) the stress distribution in the fractured bone fixed by composite plates, whose stiffness is graded both longitudinally and transversely. Results It can be seen that the stiffness-graded composite-plates cause less stress-shielding (as an example: at 50% of the healing stage, stress at the fracture interface is compressive in nature i.e. 0.002 GPa for stainless steel plate whereas stiffness graded plates provides tensile stress of 0.002 GPa. This means that stiffness graded plate is allowing the 50% healed bone to participate in loadings). Stiffness-graded plates are more flexible, and hence permit more bending of the fractured bone. This results in higher compressive stresses induced at the fractured faces accelerate bone-healing. On the other hand, away from the fracture interface the reduced stiffness and elastic modulus of the plate causes the neutral axis of the composite structure to be lowered into the bone resulting in the higher tensile stress in the bone-layer underneath the plate, wherein is conducive to the bone preserving its tensile strength. Conclusion Stiffness graded plates (with in-built variable stiffness) are deemed to offer less stress-shielding to the bone, providing higher compressive stress at the fractured interface (to induce accelerated healing) as well as higher tensile

  20. Outcome Analysis of Locking Plate Fixation in Proximal Humerus Fracture

    PubMed Central

    Pathak, Abhishek; Gaur, Sanjiv

    2016-01-01

    Introduction Proximal humerus fractures account for approximately 5% of all fractures. Stable minimally displaced fractures can be treated nonoperatively but the management of displaced fractures remain controversial with various modalities of treatment available. Locking plates provide stable fixation and enable early postoperative mobilization specially in osteoporotic proximal humerus fracture. Aim To evaluate the functional outcome of locking plate fixation and to compare the results of two approaches used for fixation. Materials and Methods This prospective study was conducted at a tertiary level hospital between September 2011 to December 2013. PHILOS plates were used for internal fixation of displaced proximal humerus fractures Neer’s type 2 part, 3 part and 4 part fractures on 26 patients (M/F ratio 1.36:1; mean age 46 years). According to Neer classification, 5,12 and 9 patients had displaced 2, 3 and 4 part fractures respectively. Deltopectoral and deltoid splitting approaches were used for fixation on 13 patients each. Functional outcome was assessed using Constant-Murley shoulder score. Graphpad software version 6.0 was used with Chi-square test and Fisher-exact test are used to compare data. The p-value< 0.05 is considered significant. Results Of the 26 patients, all fractures united radiologically and clinically and average constant score at final follow-up was 72.5. At the final follow-up 8 patients had good score, 10 patients had moderate score, 6 patients had excellent outcome and 2 patients had poor outcome according to Constant score. Mean time to union was 12.3 weeks (9 –15 weeks). Four complications (15.4%) were encountered, 2 cases of varus malunion, 1 case of wound infection which required wound debridement and 1 case of screw cut-out in which screw removal was done. Mean constant score in delto splitting approach was 70.9 and 74 in deltopectoral group (p-value= 0.54). No significant difference existed in constant score in 2 approaches

  1. Assessment of function-graded materials as fracture fixation bone-plates under combined loading conditions using finite element modelling.

    PubMed

    Fouad, H

    2011-05-01

    In previous work by Fouad (Medical Engineering and Physics 2010 [23]), 3D finite element (FE) models for fractured bones with function-graded (FG) bone-plates and traditional bone-plates made of stainless steel (SS) and titanium (Ti) alloy were examined under compressive loading conditions using the ABAQUS Code. In this study, the effects of the presence of the torsional load in addition to the compressive load on the predicted stresses of the fracture fixation bone-plate system are examined at different healing stages. The effects on the stress on the fracture site when using contacted and non-contacted bone-plate systems are also studied. The FE modelling results indicate that the torsional load has significant effects on the resultant stress on the fracture fixation bone-plate system, which should be taken into consideration during the design and the analysis. The results also show that the stress shielding at the fracture site decreases significantly when using FG bone-plates compared to Ti alloy or SS bone-plates. The presence of a gap between the bone and the plate results in a remarkable reduction in bone stress shielding at the fracture site. Therefore, the significant effects of using an FG bone-plate with a gap and the presence of torsional load on the resultant stress on the fracture fixation bone-plate system should be taken into consideration.

  2. Finite Element Analysis of Sacroiliac Joint Fixation under Compression Loads

    PubMed Central

    Bruna-Rosso, Claire; Arnoux, Pierre-Jean; Bianco, Rohan-Jean; Godio-Raboutet, Yves; Fradet, Léo

    2016-01-01

    Background Sacroiliac joint (SIJ) is a known chronic pain-generator. The last resort of treatment is the arthrodesis. Different implants allow fixation of the joint, but to date there is no tool to analyze their influence on the SIJ biomechanics under physiological loads. The objective was to develop a computational model to biomechanically analyze different parameters of the stable SIJ fixation instrumentation. Methods A comprehensive finite element model (FEM) of the pelvis was built with detailed SIJ representation. Bone and sacroiliac joint ligament material properties were calibrated against experimentally acquired load-displacement data of the SIJ. Model evaluation was performed with experimental load-displacement measurements of instrumented cadaveric SIJ. Then six fixation scenarios with one or two implants on one side with two different trajectories (proximal, distal) were simulated and assessed with the FEM under vertical compression loads. Results The simulated S1 endplate displacement reduction achieved with the fixation devices was within 3% of the experimentally measured data. Under compression loads, the uninstrumented sacrum exhibited mainly a rotation motion (nutation) of 1.38° and 2.80° respectively at 600 N and 1000 N, with a combined relative translation (0.3 mm). The instrumentation with one screw reduced the local displacement within the SIJ by up to 62.5% for the proximal trajectory vs. 15.6% for the distal trajectory. Adding a second implant had no significant additional effect. Conclusion A comprehensive finite element model was developed to assess the biomechanics of SIJ fixation. SIJ devices enable to reduce the motion, mainly rotational, between the sacrum and ilium. Positioning the implant farther from the SIJ instantaneous rotation center was an important factor to reduce the intra-articular displacement. Clinical relevance Knowledge provided by this biomechanical study enables improvement of SIJ fixation through optimal implant

  3. Plate fixation of prostheses after segmental resection for bone tumours.

    PubMed

    Coathup, M J; Cobb, J P; Walker, P S; Blunn, G W

    2000-11-01

    This study investigated the concept of using plates to attach endoprostheses to bone after segmental resection for bone tumours in an animal model. Titanium alloy plates integrated with the prosthesis and coated with hydroxyapatite were attached to bone by screws. This type of uncemented fixation relied on the induction of periosteal bone formation into and around the plates to secure the implant to bone. Two, three, and six-slotted plate designs were investigated. On retrieval, each plate was securely fixed by new bone. Bone apposition on the external surface of the plates occurred through a combination of periosteal bone production, invasion of bone through slots in the plate, and bone growth over the ends of the plates. Most plates became incorporated into a remodelled cortex. Higher bone turnover rates (microm day(-1)) were seen in bone in the slots of the plate compared with normal cortical bone turnover (p < 0.05). Significantly higher rates of turnover were measured beneath slotted parts of the plates compared with regions below the unslotted parts (p < 0.05). The cross-sectional area of bone surrounding the six-plate implant design was significantly higher than that of the three-plate (p < 0.05) and two-plate (p < 0.05) designs. In addition, significantly more bone formed adjacent to the six-plated implant design compared with that in the contralateral limb (p = 0.002). However, no significant difference was found when the total cortical area around the three-plated design was compared with that of the contralateral limb (p = 0.63). In contrast, significantly less bone was measured adjacent to the two-plate design than in the untreated limb (p = 0.001). Image analysis also demonstrated increased cortical porosity adjacent to the six-plate design compared with the three-plate (p = 0.004) and two-plate (p < 0.05) designs. Finite element analysis demonstrated that the six and three-plate designs increased the second moment of area compared with that in the

  4. Fixation of zygomatic and mandibular fractures with biodegradable plates

    PubMed Central

    Degala, Saikrishna; Shetty, Sujeeth; Ramya, S

    2013-01-01

    Context: In this prospective study, 13 randomly selected patients underwent treatment for zygomatic–complex fractures (2 site fractures) and mandibular fractures using 1.5 / 2 / 2.5-mm INION CPS biodegradable plates and screws. Aims: To assess the fixation of zygomatic-complex and mandibular fractures with biodegradable copolymer osteosynthesis system. Materials and Methods: In randomly selected 13 patients, zygomatic-complex and mandibular fractures were plated using resorbable plates and screws using Champy's principle. All the cases were evaluated clinically and radiologically for the type of fracture, need for the intermaxillary fixation (IMF) and its duration, duration of surgery, fixation at operation, state of reduction at operation, state of bone union after operation, anatomic reduction, paresthesia, occlusal discrepancies, soft tissue infection, immediate and late inflammatory reactions related to biodegradation process, and any need for the removal of the plates. Statistical Analysis Used: Descriptives, Frequencies, and Chi-square test were used. Results: In our study, the age group range was 5 to 55 years. Road traffic accidents accounted for the majority of patients six, (46.2%). Postoperative occlusal discrepancies were found in seven patients as mild to moderate, which resolved with IMF for 1-8 weeks. There were minimal complications seen and only as soft tissue infection. Conclusions: Use of biodegradable osteosynthesis system is a reliable alternative method for the fixation of zygomatic-complex and mandibular fractures. The biodegradable system still needs to be refined in material quality and handling to match the stability achieved with metal system. Biodegradable plates and screws is an ideal system for pediatric fractures with favorable outcome. PMID:23662255

  5. Reasons why dynamic compression plates are inferior to locking plates in osteoporotic bone: a finite element explanation.

    PubMed

    MacLeod, Alisdair R; Simpson, A Hamish R W; Pankaj, Pankaj

    2015-01-01

    While locking plate fixation is becoming increasingly popular for complex and osteoporotic fractures, for many indications compression plating remains the standard choice. This study compares the mechanical behaviour of the more recent locking compression plate (LCP) device, with the traditional dynamic compression plates (DCPs) in bone of varying quality using finite element modelling. The bone properties considered include orthotropy, inhomogeneity, cortical thinning and periosteal apposition associated with osteoporosis. The effect of preloads induced by compression plating was included in the models. Two different fracture scenarios were modelled: one with complete reduction and one with a fracture gap. The results show that the preload arising in DCPs results in large principal strains in the bone all around the perimeter of the screw hole, whereas for LCPs large principal strains occur primarily on the side of the screw proximal to the load. The strains within the bone produced by the two screw types are similar in healthy bone with a reduced fracture gap; however, the DCP produces much larger strains in osteoporotic bone. In the presence of a fracture gap, the DCP results in a considerably larger region with high tensile strains and a slightly smaller region with high compressive strains. These findings provide a biomechanical basis for the reported improved performance of locking plates in poorer bone quality.

  6. Stoppa Approach for Anterior Plate Fixation in Unstable Pelvic Ring Injury

    PubMed Central

    Choo, Suk Kyu; Kim, Jung-Jae; Lee, Mark

    2016-01-01

    Background The Stoppa (intrapelvic) approach has been introduced for the treatment of pelvic-acetabular fractures; it allows easy exposure of the pelvic brim, where the bone quality is optimal for screw fixation. The purpose of our study was to investigate the surgical outcomes of unstable pelvic ring injuries treated using the Stoppa approach for stable anterior ring fixation. Methods We analyzed 22 cases of unstable pelvic ring injury treated with plate fixation of the anterior ring with the Stoppa approach. We excluded cases of nondisplaced rami fracture, simple symphyseal diastasis, and parasymphyseal fractures, which can be easily treated with other techniques. The average age of the study patients was 41 years (range, 23 to 61 years). There were 10 males and 12 females. According to the Young and Burgess classification, there were 12 lateral compression, 4 anteroposterior compression, and 6 vertical shear fracture patterns. The fracture location on the anterior ring was near the iliopectineal eminence in all cases and exposure of the pelvic brim was required for plate fixation. All patients were placed in the supine position. For anterior plate fixation, all screws were applied to the anterior ramus distally and directed above the hip joint proximally. Radiologic outcomes were assessed by union time and quality of reduction by Matta method. The Merle d'Aubigne-Postel score was used to evaluate the functional results. Results The average radiologic follow-up period was 16 months (range, 10 to 51 months). All fractures united at an average of 3.5 months (range, 3 to 5 months). According to the Matta method, the quality of reduction was classified as follows: 16 anatomical (73%) and 6 nearly anatomical (27%) reductions. There were no cases of screw or implant loosening before bone healing. The functional results were classified as 7 excellent (32%), 12 good (55%), and 3 fair (13%) by the Merle d'Aubigne-Postel score. There were no wound complications

  7. Stability of extraoral vertical ramus osteotomy: plate fixation versus maxillomandibular/skeletal suspension wire fixation.

    PubMed

    Mobarak, K A; Krogstad, O; Espeland, L; Lyberg, T

    2000-01-01

    The objective of this cephalometric study was to evaluate skeletal stability and time course of postoperative changes in 2 groups of mandibular prognathism patients following extraoral oblique vertical ramus osteotomy (VRO). One group (n = 22) received maxillomandibular fixation and skeletal suspension wires (MMF group) for a period of 8 weeks. In the other group (n = 22), the segments were rigidly fixed with plates and the patients were allowed to function immediately after surgery. Lateral cephalograms were taken on 5 occasions: immediately presurgical, immediately postsurgical, 8 weeks postsurgical, 6 months postsurgical, and 1 year postsurgical. During the first 8 weeks after surgery, the MMF group demonstrated posterior movement of the mandible, with an increase in mandibular plane angle, shortening of the rami, and dental compensations. Upon release of MMF and skeletal suspension wiring, a small anterior relapse tendency was observed, but the net setback 1 year after surgery was still greater than the actual surgical setback. In the plate fixation group, postoperative changes were mainly in the form of a small anterior relapse tendency in the range of 10% of the surgical setback. The results indicate that the use of plate fixation with VRO, while eliminating the inconvenience for the patient of several weeks of MMF and preventing the early side effects observed in the MMF group, also resulted in a more predictable surgical procedure, with excellent stability 1 year after surgery.

  8. Compression behavior of delaminated composite plates

    NASA Technical Reports Server (NTRS)

    Peck, Scott O.; Springer, George S.

    1989-01-01

    The response of delaminated composite plates to compressive in-plane loads was investigated. The delaminated region may be either circular or elliptical, and may be located between any two plies of the laminate. For elliptical delaminations, the axes of the ellipse may be arbitrarily oriented with respect to the applied loads. A model was developed that describes the stresses, strains, and deformation of the sublaminate created by the delamination. The mathematical model is based on a two dimensional nonlinear plate theory that includes the effects of transverse shear deformation. The model takes into account thermal and moisture induced strains, transverse pressures acting on the sublaminate, and contact between the sublaminate and plate. The solution technique used is the Ritz method. A computationally efficient computer implementation of the model was developed. The code can be used to predict the nonlinear-load-strain behavior of the sublaminate including the buckling load, postbuckling behavior, and the onset of delamination growth. The accuracy of the code was evaluated by comparing the model results to benchmark analytical solutions. A series of experiments was conducted on Fiberite T300/976 graphite/epoxy laminates bonded to an aluminum honeycomb core forming a sandwich panel. Either circles or ellipses made from Teflon film were embedded in the laminates, simulating the presence of a delamination. Each specimen was loaded in compression and the strain history of the sublaminate was recorded far into the postbuckling regime. The extent of delamination growth was evaluated by C-scan examination of each specimen. The experimental data were compared to code predictions. The code was found to describe the data with reasonable accuracy. A sensitivity study examined the relative importance of various material properties, the delamination dimensions, the contact model, the transverse pressure differential, the critical strain energy release rate, and the relative

  9. Compressive strength of damaged and repaired composite plates

    NASA Technical Reports Server (NTRS)

    Finn, Scott R.; Springer, George S.

    1992-01-01

    Tests were performed assessing the effectiveness of repair in restoring the mechanical properties of damaged, solid composite plates made of Fiberite T300/976 graphite-epoxy. Some (75%) or all (100%) of the damaged zone was cut out, and the plate was repaired by plugging and patching the hole. The effectiveness of the repair was evaluated by measuring the compressive strengths of undamaged plates, damaged plates with no cutout, damaged plates with a cutout, and plates that had been repaired.

  10. A comparative in vitro study of fixation of mandibular fractures with paraskeletal clamps or screw plates.

    PubMed

    Crofts, C E; Trowbridge, A; Maung Aung, T; Brook, I M

    1990-05-01

    The use of porcine rib pairs as an in vitro analog for the edentulous mandible is described. Using this model, the relative degree of fixation achieved with a screw plate (Champy) and a paraskeletal clamp plate (Mennen) has been evaluated. The fractured plated ribs failed at significantly lower bending forces than the non-sectioned controls. However, no statistically significant difference in force at failure between the two different methods of plate fixation could be demonstrated.

  11. Tibial Lengthening Using a Fixator-Assisted Lengthening Plate: A New Technique

    PubMed Central

    Tosun, Haci Bayram; Agir, Ismail; Gumustas, Seyitali; Serbest, Sancar; Uludag, Abuzer; Celik, Suat

    2016-01-01

    Background There are many techniques that are used for limb lengthening. Lengthening a limb over a plate is an alternative choice used in children or when using an intramedullary nail is difficult. Objectives In this study, we presented a new technique for tibial lengthening using a monolateral external fixator over a lengthening plate. Materials and Methods For tibial lengthening, a monolateral external fixator was attached to the composite bone model medially. After a corticotomy was performed, the lengthening plate was placed laterally. Three locking screws were inserted proximally, and two cortical screws were inserted into a lengthening hole that was 1 cm below the osteotomy site. We avoided contact between the screws of the lengthening plate and the pins of the external fixator. During bone lengthening with the monolateral external fixator, the screws at the lengthening hole were able to slide distally with the distal segment of the tibia to allow for tibial elongation. Two locking screws were fixed at the distal locking holes of the plate when the bone elongation was complete. The external fixator was then removed. Results The fixator-assisted lengthening plate allowed bone lengthening without malalignment. There were no mechanical problems associated with the external fixator during the lengthening process. Plate osteosynthesis was stable after the fixator was removed. There was no contact between the screws of plate and the Schanz pins of the external fixator under C-arm fluoroscopy. Conclusions The fixator-assisted lengthening plate technique helps to maintain the stability and alignment at both sides of an osteotomy during tibial elongation. It allows the early removal of the external fixator immediately after lengthening is completed. This technique can be applied in children with open physes and in patients with a narrow medullary canal who are unsuitable for limb lengthening over an intramedullary nail. PMID:28184364

  12. Investigation of the mechanical properties and failure modes of hybrid natural fiber composites for potential bone fracture fixation plates.

    PubMed

    Manteghi, Saeed; Mahboob, Zia; Fawaz, Zouheir; Bougherara, Habiba

    2017-01-01

    The purpose of this study is to investigate the mechanical feasibility of a hybrid Glass/Flax/Epoxy composite material for bone fracture fixation such as fracture plates. These hybrid composite plates have a sandwich structure in which the outer layers are made of Glass/Epoxy and the core from Flax/Epoxy. This configuration resulted in a unique structure compared to prior composites proposed for similar clinical applications. In order to evaluate the mechanical properties of this hybrid composite, uniaxial tension, compression, three-point bending and Rockwell Hardness tests were conducted. In addition, water absorption tests were performed to investigate the rate of water absorption for the specimens. This study confirms that the proposed hybrid composite plates are significantly more flexible axially compared to conventional metallic plates. Furthermore, they have considerably higher ultimate strength in tension, compression and flexion. Such high strength will ensure good stability of bone-implant construct at the fracture site, immobilize adjacent bone fragments and carry clinical-type forces experienced during daily normal activities. Moreover, this sandwich structure with stronger and stiffer face sheets and more flexible core can result in a higher stiffness and strength in bending compared to tension and compression. These qualities make the proposed hybrid composite an ideal candidate for the design of an optimized fracture fixation system with much closer mechanical properties to human cortical bone.

  13. Biomechanical Study of the Fixation Strength of Anteromedial Plating for Humeral Shaft Fractures

    PubMed Central

    Zheng, Yin-Feng; Zhou, Jun-Lin; Wang, Xiao-Hong; Shan, Lei; Liu, Yang

    2016-01-01

    Background: Open reduction and internal fixation with plate and screws are the gold standard for the surgical treatment of humeral shaft fractures, this study was to compare the mechanical properties of anteromedial, anterolateral, and posterior plating for humeral shaft fractures. Methods: A distal third humeral shaft fracture model was constructed using fourth-generation sawbones (#3404, composite bone). A total of 24 sawbones with a distal third humeral shaft fracture was randomly divided into three Groups: A, B, and C (n = 8 in each group) for anteromedial, anterolateral, and posterior plating, respectively. All sawbones were subjected to horizontal torsional fatigue tests, horizontal torsional and axial compressive fatigue tests, four-point bending fatigue tests in anteroposterior (AP) and mediolateral (ML) directions and horizontal torsional destructive tests. Results: In the horizontal torsional fatigue tests, the mean torsional angle amplitude in Groups A, B, and C were 6.12°, 6.53°, and 6.81°. In horizontal torsional and axial compressive fatigue tests, the mean torsional angle amplitude in Groups A, B, and C were 5.66°, 5.67°, and 6.36°. The mean plate displacement amplitude was 0.05 mm, 0.08 mm, and 0.10 mm. Group A was smaller than Group C (P < 0.05). In AP four-point bending fatigue tests, the mean plate displacement amplitude was 0.16 mm, 0.13 mm, and 0.20 mm. Group B was smaller than Group C (P < 0.05). In ML four-point bending fatigue tests, the mean plate displacement amplitude were 0.16 mm, 0.19 mm, and 0.17 mm. In horizontal torsional destructive tests, the mean torsional rigidity in Groups A, B, and C was 0.82, 0.75, and 0.76 N·m/deg. The yielding torsional angle was 24.50°, 25.70°, and 23.86°. The mean yielding torque was 18.46, 18.05, and 16.83 N·m, respectively. Conclusions: Anteromedial plating was superior to anterolateral or posterior plating in all mechanical tests except in AP four-point bending fatigue tests compared to the

  14. Distraction osteogenesis using combined locking plate and Ilizarov fixator in the treatment of bone defect: A report of 2 cases

    PubMed Central

    Mukhopadhaya, John; Raj, Manish

    2017-01-01

    Distraction osteogenesis and bone transport has been used to reconstruct bone loss defect by allowing new bone to form in the gap. Plate-guided bone transport has been successfully described in literature to treat bone loss defect in the femur, tibia, and mandible. This study reports two cases of fracture of femur with segmental bone loss treated with locking plate fixation and bone transport with Ilizarov ring fixator. At the time of docking, when the transport segment is compressed with bone fragment, the bone fragment is fixed with additional locking or nonlocking screws through the plate. The bone defect size was 7 cm in case 1 and 8 cm in case 2 and the external fixation indexes were 12.7 days/cm and 14 days/cm. No shortening was present in either of our cases. The average radiographic consolidation index was 37 days/cm. Both cases achieved infection-free bone segment regeneration and satisfactorily functional outcome. This technique reduces the duration of external fixation during the consolidation phase, allows correction of length and alignment and provides earlier rehabilitation.

  15. Determination of Plate Compressive Strengths at Elevated Temperatures

    NASA Technical Reports Server (NTRS)

    Heimerl, George J; Roberts, William M

    1950-01-01

    The results of local-instability tests of h-section plate assemblies and compressive stress-strain tests of extruded 75s-t6 aluminum alloy, obtained to determine flat-plate compressive strength under stabilized elevated temperature conditions, are given for temperatures up to 600 degrees F. The results show that methods available for calculating the critical compressive stress at room temperature can also be used at elevated temperatures if the applicable compressive stress-strain curve for the material is given.

  16. Treatment of Palatal Fractures by Osteosynthesis with 2.0-mm Locking Plates as External Fixator

    PubMed Central

    Cienfuegos, Ricardo; Sierra, Eduardo; Ortiz, Benjamin; Fernández, Gerardo

    2010-01-01

    Treatment options for palatal fractures range from orthodontic braces, acrylic bars, and arch bars for maxillomandibular fixation to internal fixation, with plates and screws placed under the palate mucosa and periosteum, together with pyriform aperture or alveolar plating plus buttress reconstruction. Forty-five patients, ages 4 to 56, were treated using medium- or high-profile locking plates placed over the palatal mucosa as an external fixator for palatal fractures, together with treatment for other associated facial fractures. In open fractures, plates were placed after approximating the edges of the mucosal wounds. Plates and screws for palate fixation were removed at 12 weeks, when computed tomography scans provided evidence of fracture healing. All palatal fractures healed by 12 weeks, with no cases of mucosal necrosis, bone exposure, fistulae, or infections. This approach achieves adequate stability, reduces the risk of bone and mucosal necrosis, and promotes healing of mucosal wounds in case of open fractures. PMID:22132261

  17. Plate fixation of periprosthetic femur fractures: What happens to the cement mantle?

    PubMed

    Konstantinidis, Lukas; Schmidt, Benjamin; Bernstein, Anke; Hirschmüller, Anja; Schröter, Steffen; Südkamp, Norbert Paul; Helwig, Peter

    2017-02-01

    Osteosynthesis of periprosthetic femur fractures by screw fixation around the implanted prosthetic stem is currently regarded as the biomechanically superior option compared with cerclage. The aim of this biomechanical study was damage analysis of the cement mantle after revision screw insertion. A prosthetic stem (Bicontact) was implanted in 20 cadaveric femora in cemented technique. A locking compression plate (Synthes) was then applied to the lateral femur at the level of the prosthetic stem. The method of plate fixation to the femur was assigned randomly to three groups: bicortical non-locking screws, monocortical locking screws, and bicortical locking screws. This was followed by applying a fluctuating axial load (2100 N, 0.5 Hz) for 20,000 cycles. After testing, macroscopic and microscopic evaluations of the cement mantle were conducted. Cracks formed in the cement mantle in 14% of the 80 screw holes. The type of screw (bicortical or monocortical; locking or non-locking) had no significant effect on the number of cracks (p = 0.52). The relationship between manifestation of crack damage and cement mantle thickness was not significant (p = 0.36), whereas the relationship between crack formation and screw position was significant (p = 0.019). Those screws whose circumference was only partially within the cement mantle yielded a significantly lower number of cracks compared with screws positioned completely within the cement mantle or even touching the prosthetic stem. In order to reduce the incidence of crack formation in the cement mantle during plate osteosynthesis of periprosthetic femur fractures, the screws should not be either placed within the cement mantle or make direct contact with the stem.

  18. Design of Fracture Fixation Plate for Necessary and Sufficient Bone Stress Shielding

    NASA Astrophysics Data System (ADS)

    Ramakrishna, Kotlanka; Sridhar, Idapalapati; Sivashanker, Sathiamoorthy; Khong, Kok Sun; Ghista, Dhanjoo N.

    The objective of treating the fractured bone is to achieve painless functioning of the bone and undisturbed healing at the fracture. Internal fixation by stiff bone-plate is one of the standard methods to achieve these objectives. Recently, there is considerable interest in the usage of compliant plates to enhance bone healing with reduced stress shielding. Herein, first an analytical solution is developed to determine screw forces in the bone-plate assembly that conforms the plate and the bone under bending load. Based on the analytical calculations, an optimal fixator plate selection criterion for necessary and sufficient stress shielding is proposed. Second, effectiveness of employing a non-homogeneous stiffness graded (SG) plate rather than a homogeneous stainless steel (SS) plate for stress shielding is investigated using a finite element method. It is found that stress shielding on bone by SG plate is less compared to SS plate.

  19. Incipient transition phenomena in compressible flows over a flat plate

    NASA Technical Reports Server (NTRS)

    Erlebacher, G.; Hussaini, M. Y.

    1986-01-01

    The full three-dimensional time-dependent compressible Navier-Stokes equations are solved by a Fourier-Chebyshev method to study the stability of compressible flows over a flat plate. After the code is validated in the linear regime, it is applied to study the existence of the secondary instability mechanism in the supersonic regime.

  20. Compressive strength of damaged and repaired composite plates

    NASA Technical Reports Server (NTRS)

    Finn, Scott R.; He, Yi-Fei; Springer, George S.; Lee, Hung-Joo

    1992-01-01

    Tests were performed assessing the effectiveness of repair in restoring the mechanical properties of damaged, solid composite plates made either of Fiberite T300/976 graphite-epoxy, Fiberite IM7/977-2 graphite-toughened epoxy, or ICI APC-2 graphite-PEEK. The plate length, the layup and the amount of damage were also varied. Damage was introduced in the plates either by impacting them with a solid projectile or by applying a transverse static load. Some (75 percent) or all (100 percent) of the damaged zone was then cut out, and the plate was repaired by plugging and patching the hole. The effectiveness of the repair was evaluated by measuring the compressive strengths of undamaged plates, damaged plates with no cutout, damaged plates with a cutout, and repaired plates. The data at an intermediate stage of repair provide information on the effect of each repair step on the compressive strength. The results indicated that for the solid plates used in these tests, the repair methods used herein did not improve the compressive strength of already damaged plates.

  1. Current Evidence: Plate Versus Intramedullary Nail for Fixation of Distal Tibia Fractures in 2016.

    PubMed

    Vallier, Heather A

    2016-11-01

    Displaced distal tibia shaft fractures are effectively treated with standard plates and intramedullary nails. Plate fixation performed with meticulous soft tissue handling results in minimal risks of infection and poor wound healing. Standard plates have high rates of primary union, whereas locking plates may delay union because of increased stiffness. Tibial healing may also be delayed after plating of the fibula, although fibula reduction and fixation may aid accuracy of reduction of the tibia. Malalignment occurs more often with infrapatellar intramedullary nailing versus plates, and early results of suprapatellar nailing appear promising in minimizing intraoperative malalignment. Long-term function after fixation of the distal tibia is good for most, with poor outcomes often associated with baseline social and mental health issues.

  2. The apparent width of the plate in compression

    NASA Technical Reports Server (NTRS)

    Marguerre, Karl

    1937-01-01

    The following investigation treats the load capacity of a rectangular plate stressed in compression on one direction (x) beyond the buckling limit. The plate is rotatable (i.e., free from moments) supported at all four sides by bending-resistant beams.

  3. Dynamic Stabilization of Simple Fractures With Active Plates Delivers Stronger Healing Than Conventional Compression Plating

    PubMed Central

    Tsai, Stanley; Bliven, Emily K.; von Rechenberg, Brigitte; Kindt, Philipp; Augat, Peter; Henschel, Julia; Fitzpatrick, Daniel C.; Madey, Steven M.

    2017-01-01

    Objectives: Active plates dynamize a fracture by elastic suspension of screw holes within the plate. We hypothesized that dynamic stabilization with active plates delivers stronger healing relative to standard compression plating. Methods: Twelve sheep were randomized to receive either a standard compression plate (CP) or an active plate (ACTIVE) for stabilization of an anatomically reduced tibial osteotomy. In the CP group, absolute stabilization was pursued by interfragmentary compression with 6 cortical screws. In the ACTIVE group, dynamic stabilization after bony apposition was achieved with 6 elastically suspended locking screws. Fracture healing was analyzed weekly on radiographs. After sacrifice 9 weeks postsurgery, the torsional strength of healed tibiae and contralateral tibiae was measured. Finally, computed tomography was used to assess fracture patterns and healing modes. Results: Healing in both groups included periosteal callus formation. ACTIVE specimens had almost 6 times more callus area by week 9 (P < 0.001) than CP specimens. ACTIVE specimens recovered on average 64% of their native strength by week 9, and were over twice as strong as CP specimens, which recovered 24% of their native strength (P = 0.008). Microcomputed tomography demonstrated that compression plating induced a combination of primary bone healing and gap healing. Active plating consistently stimulated biological bone healing by periosteal callus formation. Conclusions: Compared with compression plating, dynamic stabilization of simple fractures with active plates delivers significantly stronger healing. PMID:27861456

  4. Distal radius fractures: Minimally invasive plate osteosynthesis with dorsal bicolumnar locking plates fixation

    PubMed Central

    Chen, Alvin Chao-Yu; Chou, Ying-Chao; Cheng, Chun-Ying

    2017-01-01

    Background: Controversy still exists regarding the current treatment modalities for unstable distal radius fractures. There are yet few articles investigating the efficacy of bicolumnar dorsal plating technique, which is designed to minimize tissue dissection while providing sufficiently secure fixation. A clinical study was performed to evaluate the feasibility of the minimally invasive plate osteosynthesis (MIPO) technique using a modified dorsal approach for the treatment of distal radius fractures. Materials and Methods: Thirty patients with unilateral distal radius fracture who underwent bicolumnar plate fixation with a minimally invasive dorsal approach between September 2008 and December 2010 were included in this retrospective study. Twenty four patients (8 men and 16 women) with a mean age of 53 years (range 18-85 years) were available for followup of at least 1 year or more were included in final study. Herein, we report the functional radiological outcomes of the study. There were three cases of AO Type A fracture, five cases of AO Type B fracture, and 16 cases of AO Type C fracture. Results: The union was achieved in all the patients. The functional results at one-year followup, assessed using the modified Gartland and Werley scoring system, were excellent in 14 patients, good in seven patients, and fair in three patients. The average correction of deformity was 4.1 mm for radial height, 7.6° for radial inclination, and 20.7° for volar tilt. Conclusions: MIPO with a dorsal approach is a feasible option for the management of displaced distal radius fractures and can result in favorable surgical outcomes. PMID:28216757

  5. Design and experimental evaluation of adjustable bone plates for mandibular fracture fixation.

    PubMed

    Cervantes, Thomas M; Slocum, Alexander H; Seldin, Edward B

    2012-01-03

    Conventional bone plates are commonly used for surgical mandibular fracture fixation. Improper alignment between bone segments, however, can result in malocclusion. Current methods of fixation require a surgeon to visually align segments of bone and affix a metal plate using bone screws, after which little can be done to adjust alignment. A method of adjusting fracture alignment after plate placement, without screw removal, presents an improvement over costly and risky revision surgery. A modified bone plate has been designed with a deformable section to give surgeons the ability to reduce misalignments at the fracture site. The mechanics of deformation for various adjustment mechanisms was explored analytically, numerically, and experimentally to ensure that the adjustable plate is comparable to conventional bone plates. A static force of 358.8 N is required to deform the adjustable bone plate, compared with predicted values of 351 N using numerical simulation and 362 N using a simple beam theory. Dynamic testing was performed to simulate in vivo loading conditions and evaluate load-capacity in both deformed and un-deformed bone plates. Results indicate that bending stiffness of a rectangular bone plate is 709 N/mm, compared with 174 N/mm for an octagonal plate and 176 N/mm for standard plates. Once deformed, the rectangular and octagonal plates had a stiffness of 323 N/mm and 228 N/mm, respectively. Un-deformed and deformed adjustable bone plates have efficacy in bone segment fixation and healing.

  6. Femoral locking plate failure salvaged with hexapod circular external fixation: a report of two cases.

    PubMed

    Ferreira, N; Marais, L C

    2016-08-01

    Femoral non-unions are difficult to treat even for the experienced orthopaedic trauma surgeon. If the non-union follows failure of modern stable internal fixation, the complexity of the management is further increased. We report two cases of stiff hypertrophic femoral non-unions after failed locking plate fixation that were successfully treated with a new hexapod circular external fixator. In addition to providing the necessary stability for functional rehabilitation and union, the hexapod circular fixator software allows gradual correction of deformities in order to restore the normal mechanical alignment of the limb.

  7. Biomechanical evaluation of the fixation methods for transcondylar fracture of the humerus:ONI plate versus conventional plates and screws.

    PubMed

    Shimamura, Yasunori; Nishida, Keiichiro; Imatani, Junya; Noda, Tomoyuki; Hashizume, Hiroyuki; Ohtsuka, Aiji; Ozaki, Toshifumi

    2010-04-01

    We biomechanically evaluated the bone fixation rigidity of an ONI plate (Group I) during fixation of experimentally created transcondylar humerus fractures in cadaveric elbows, which are the most frequently observed humeral fractures in the elderly, and compared it with the rigidity achieved by 3 conventional fixation methods:an LCP reconstruction plate 3.5 using a locking mechanism (Group II), a conventional reconstruction plate 3.5 (CRP) with a cannulated cancellous screw (Group III), and a CRP with 2 cannulated cancellous screws (CS) in a crisscross orientation (Group IV). In the axial loading test, the mean failure loads were:Group I, 98.9+/-32.6;Group II, 108.5+/-27.2;Group III, 50.0+/-7.5;and Group IV, 34.5+/-12.2 (N). Group I fixations failed at a significantly higher load than those of Groups III and IV (p<0.05). In the extension loading test, the mean failure loads were:Group I, 34.0+/-12.4;Group II, 51.0+/-14.8;Group III, 19.3+/-6.0;and Group IV, 14.7+/-3.1 (N). Group IV fixations showed a significantly lower failure load than those of Group I (p<0.05). The fixation rigidities against mechanical loading by the ONI plate and LCP plate were comparable. These results suggested that an ONI system might be superior to the CRP and CS method, and comparable to the LCP method in terms of fixation rigidity for distal humerus fractures.

  8. External Fixation Versus Open Reduction With Locked Volar Plating for Geriatric Distal Radius Fractures

    PubMed Central

    Lee, Daniel J.

    2014-01-01

    The optimal management of displaced dorsal radius fractures (DRFs) in older patients remains an issue of debate. Bridging external fixation is a well-accepted treatment modality for severely comminuted DRFs, while open reduction and internal fixation with locked volar plating has emerged as a promising alternative in recent years. The current body of randomized trials supports the trend toward locked volar plating, as it allows for quicker improvement in subjective and functional outcomes. There is no clear evidence to suggest that one technique carries significantly less complications than the other. Locked volar plating should be considered in patients for whom an accelerated functional recovery would be advantageous. Otherwise, both external fixation and locked volar plating provide good long-term clinical outcomes. PMID:25360346

  9. A Novel Computer-Aided Approach for Parametric Investigation of Custom Design of Fracture Fixation Plates

    PubMed Central

    2017-01-01

    The present study proposes an integrated computer-aided approach combining femur surface modeling, fracture evidence recover plate creation, and plate modification in order to conduct a parametric investigation of the design of custom plate for a specific patient. The study allows for improving the design efficiency of specific plates on the patients' femur parameters and the fracture information. Furthermore, the present approach will lead to exploration of plate modification and optimization. The three-dimensional (3D) surface model of a detailed femur and the corresponding fixation plate were represented with high-level feature parameters, and the shape of the specific plate was recursively modified in order to obtain the optimal plate for a specific patient. The proposed approach was tested and verified on a case study, and it could be helpful for orthopedic surgeons to design and modify the plate in order to fit the specific femur anatomy and the fracture information. PMID:28203270

  10. A Novel Computer-Aided Approach for Parametric Investigation of Custom Design of Fracture Fixation Plates.

    PubMed

    Chen, Xiaozhong; He, Kunjin; Chen, Zhengming

    2017-01-01

    The present study proposes an integrated computer-aided approach combining femur surface modeling, fracture evidence recover plate creation, and plate modification in order to conduct a parametric investigation of the design of custom plate for a specific patient. The study allows for improving the design efficiency of specific plates on the patients' femur parameters and the fracture information. Furthermore, the present approach will lead to exploration of plate modification and optimization. The three-dimensional (3D) surface model of a detailed femur and the corresponding fixation plate were represented with high-level feature parameters, and the shape of the specific plate was recursively modified in order to obtain the optimal plate for a specific patient. The proposed approach was tested and verified on a case study, and it could be helpful for orthopedic surgeons to design and modify the plate in order to fit the specific femur anatomy and the fracture information.

  11. 16. View of riveted gusset plate connection between compression diagonal, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. View of riveted gusset plate connection between compression diagonal, tension diagonal, and lateral brace at center of 4th panel from north end of west truss of north span, looking from the east - Bridge No. 4900, Spanning Root River at Trunk Highway 16, Rushford, Fillmore County, MN

  12. Percutaneous K-wire fixation versus palmar plating with locking screws for Colles' fractures.

    PubMed

    Hollevoet, Nadine; Vanhoutie, Tom; Vanhove, Wim; Verdonk, René

    2011-04-01

    Different methods exist to treat distal radius fractures. A prospective randomized study was conducted to establish whether palmar plate fixation with locking screws gave better results than percutaneous K-wire fixation in patients over 50 years of age. Only fractures with dorsal displacement after a simple fall were included in the study. Twenty wrists were treated with K-wires and 20 with a plate. Radiological parameters were measured on preoperative radiographs and at five weeks postoperatively. Clinical results and DASH scores were determined at three months postoperatively and at more than one year. No significant difference in radial inclination, palmar tilt, clinical outcome and DASH score was found between plating and K-wires, but the mean difference in ulnar variance between pre- and postoperative radiographs was significantly better with plates. It can be concluded that plates were superior to K-wires in restoring ulnar variance, but functional outcome was similar with both techniques.

  13. Radiographic Comparison of Four Anterior Fusion Methods in Two Level Cervical Disc Diseases : Autograft Plate Fixation versus Cage Plate Fixation versus Stand-Alone Cage Fusion versus Corpectomy and Plate Fixation

    PubMed Central

    Kim, Min-Ki; Jeon, Kwang-Mo; Kim, Tae-Sung

    2012-01-01

    Objective To evaluate radiographic results of anterior fusion methods in two-level cervical disc disease : tricortical autograft and plate fixation (ACDF-AP), cage and plate fixation (ACDF-CP), stand-alone cage (ACDF-CA), and corpectomy and plate fixation (ACCF). Methods The numbers of patients were 70 with a minimum 6 month follow-up (ACDF-AP : 12, ACDF-CP : 27, ACDF-CA : 15, and ACCF : 16). Dynamic simple X-ray and computed tomography were evaluated preoperatively, postoperatively, 6 month, and at the final follow-up. The fusion and subsidence rates at the final were determined, and global cervical lordosis (GCL), cervical range of motion, fused segment angle (FSA), and fused segment height (FSH) were analyzed. Results Nonunion was observed in 4 (25%) patients with ACDF-CA, 1 (8%) patient with ACDF-AP, 1 (4%) patient with ACDF-CP. The number of loss of FSH (%) more than 3 mm were 2 patients (16%) in ACDF-AP, 3 patients (11%) in ACDF-CP, 5 patients (33%) in ACDF-CA, and 3 patients (20%) in ACCF. The GCL was decreased with ACDF-CA and increased with others. The FSA was increased with ACDF-AP, ACDF-CP, and ACCF, but ACDF-CA was decreased. At the final follow-up, the FSH was slightly decreased in ACDF-CP, ACDF-AP, and ACCF, but ACDF-CA was more decreased. Graft related complication were minimal. Screw loosening, plate fracture, cage subsidence and migration were not identified. Conclusion ACDF-CP demonstrated a higher fusion rate and less minimal FSH loss than the other fusions in two-level cervical disc disease. The ACDF-AP and ACCF methods had a better outcome than the ACDF-CA with respect to GCL, FSA, and FSH. PMID:22639708

  14. Stress-riser fractures of the hip after sliding screw plate fixation.

    PubMed

    DiMaio, F R; Haher, T R; Splain, S H; Mani, V J

    1992-10-01

    Fractures occurring after fixation of intertrochanteric femur fractures have been described previously in the literature. Terms such as "stress-riser fracture" and "Young's modulus fracture" have been applied. The prevalence of these fracture types has increased, and so has use of the sliding screw plate device for fixation of intertrochanteric hip fractures. The object of this paper is to describe, by case examples, types of stress-related fractures of the proximal femur in association with the sliding screw plate and to define each biomechanical type in review.

  15. Fixator-assisted tibial lengthening over a plate in a patient with sequelae of poliomyelitis.

    PubMed

    Tosun, Haci Bayram; Serbest, Sancar; Uludag, Abuzer; Gumustas, Seyitali; Celik, Suat

    2016-11-01

    There are many techniques for limb lengthening. Lengthening over a plate is an alternative choice of fixation in children or when nailing is difficult. We present a new technique for tibial lengthening with using a monolateral external fixator over a lengthening plate.Lengthening over an intramedullary nail is a commonly used method in patients with short stature or limb-length discrepancy. However, in patients with a narrow and excessively sclerotic intramedullary cavity in the pediatric age group where the skeletal system has not yet fully developed, difficulties have been observed in lengthening methods with nailing.Therefore, in these cases, the use of lengthening techniques over a plate is an alternative treatment option. Nevertheless, in lengthening techniques over a plate, if one side of the osteotomy area cannot be fixed, associated mechanical axis problems have been reported.We applied tibia lengthening with external fixator assistance over a custom-made lengthening plate in a patient with sequelae of poliomyelitis. This new lengthening technique applied over a plate could be the solution to the problems observed in other lengthening techniques over a plate.

  16. The effects of physiologic dynamic compression on bone healing under external fixation

    SciTech Connect

    Aro, H.T.; Kelly, P.J.; Lewallen, D.G.; Chao, E.Y. )

    1990-07-01

    The effects of early physiologic dynamic compression on fracture healing were studied in the dog. Transverse midtibial osteotomies were performed bilaterally and stabilized with a relatively rigid external fixation system in a neutralization mode (800 microns) to prevent compression of the osteotomy ends during weight bearing. On the 15th day, one osteotomy in each animal was subjected to dynamic compression through weight bearing by release of the fixator-telescoping mechanism (axial dynamization), while the other side remained unchanged as the control. Analysis of sequential roentgenograms showed that the callus distribution was more symmetric on the dynamic compression side. The two sides showed no significant differences in quantitative technetium-99 bone scans or in osteotomy-site blood flow. There were no statistical differences in new bone formation, bone porosity, or maximum torque between sides. The fixation had maintained the initially created osteotomy gap on the control side and tended to unite through a gap-healing mechanism. The dynamic compression side showed reduction in gap size and union by more of a contact-healing mechanism. There were no statistical differences in the rate of pin loosening, but its distribution according to pin location was significantly different between the two sides.

  17. Analysis of gene expression profiles in healing rat fractures treated with nail and plate fixation.

    PubMed

    Wang, S D; Li, X L; Liu, H P

    2014-10-20

    To compare fracture healing therapies, the gene expression profiles of rat fracture samples treated with nail and plate fixation were analyzed at 1 day, 3 days, 1 week, 2 weeks, 4 weeks, and 6 weeks after surgery. The gene expression profiles GSE1685, which include 19 samples, were downloaded from the Gene Expression Omnibus database. After preprocessing, the gene expression profiles were subjected to time series analysis using the Short Time-series Expression Miner software, and the significantly differentially expressed gene (DEG) sets were selected. Further, the distributions of those DEG sets on the corresponding chromosomes were identified using the functional classification tool. Finally, the DEGs were subjected to function and pathway enrichment analysis. DEG analysis indicated that the number of DEGs (854 genes) from nail fixation was significantly lower than that of DEGs (1029 genes) from plate fixation. The DEGs were mainly enriched in cell proliferation, cellular localization, and response to wounding functions. Several critical DEGs expressed during the fracture healing process were screened, and 2 common pathways were enriched for the DEGs in the nail fixation and plate fixation. These DEGs and pathways may be potential targets or predictive markers during fracture healing.

  18. Fixation of Soft-inner Part of Oil Palm Trunk by Close System Compression Method

    NASA Astrophysics Data System (ADS)

    Hartono, R.; Dwianto, W.; Wahyudi, I.; Febrianto, F.; Morooka, T.

    2017-03-01

    Compression by closes system compression (CSC) improved quality of the soft-inner part of oil palm trunk (S-OPT). The problem of compressed-wood was spring back or recovery of set, if it was exposed to moisture content. The objective of these study were to evaluate the recovery of set (RS) and weight loss (WL) of S-OPT by CSC. These methods were compared with heat treatment (HT) and steam treatment (ST). Density of S-OPT was 0.3 g/cm3. All samples were compressed to compression ratio of 50%. The compression of HT method used the temperatur of 120, 140, 160, 180 and 200 °C for 0, 10, 30, 60 and 180 minutes; and ST method used temperature of 120, 140, 160, 170 and 180 °C for 0, 5, 10 and 30 minute; while CSC method used temperature of 120, 140, 160, 180 and 200 °C for 0, 10, 20, 30 and 40 minutes. The results showed that the temperature and compression time contributed to the RS and WL value for all methods. Increasing compression temperature and time leads to decreased the RS value and to increased the WL value. The lower RS value indicated that S-OPT fixation would be better or high dimensional stability. Fixation of S-OPT by ST method was achieved at temperature of 170 °C for 30 min, CSC at temperature of 180 °C for 30 min, while HT method has not fixated until 200 °C for 180 min.

  19. Experimental fracture model versus osteotomy model in metacarpal bone plate fixation.

    PubMed

    Ochman, S; Vordemvenne, T; Paletta, J; Raschke, M J; Meffert, R H; Doht, S

    2011-01-01

    Introduction. Osteotomy or fracture models can be used to evaluate mechanical properties of fixation techniques of the hand skeleton in vitro. Although many studies make use of osteotomy models, fracture models simulate the clinical situation more realistically. This study investigates monocortical and bicortical plate fixation on metacarpal bones considering both aforementioned models to decide which method is best suited to test fixation techniques. Methods. Porcine metacarpal bones (n = 40) were randomized into 4 groups. In groups I and II bones were fractured with a modified 3-point bending test. The intact bones represented a further control group to which the other groups after fixation were compared. In groups III and IV a standard osteotomy was carried out. Bones were fixated with plates monocortically (group I, III) and bicortically (group II, IV) and tested for failure. Results. Bones fractured at a mean maximum load of 482.8 N ± 104.8 N with a relative standard deviation (RSD) of 21.7%, mean stiffness was 122.3 ± 35 N/mm. In the fracture model, there was a significant difference (P = 0.01) for maximum load of monocortically and bicortically fixed bones in contrast to the osteotomy model (P = 0.9). Discussion. In the fracture model, because one can use the same bone for both measurements in the intact state and the bone-plate construct states, the impact of inter-individual differences is reduced. In contrast to the osteotomy model there are differences between monocortical and bicortical fixations in the fracture model. Thus simulation of the in vivo situation is better and seems to be suitable for the evaluation of mechanical properties of fixation techniques on metacarpals.

  20. Analysis of Sternal Fixation Results According to Plate Type in Sternal Fracture

    PubMed Central

    Byun, Chun Sung; Park, Il Hwan; Hwang, Wan Jin; Lee, Yeiwon; Cho, Hyun Min

    2016-01-01

    Background Sternal fractures are relatively rare, and caused mainly by blunt anterior chest wall trauma. In most cases, sternal fractures are treated conservatively. However, if the patient exhibits problematic symptoms such as intractable chest wall pain or bony crepitus due to sternal instability, surgical correction is indicated. But no consensus exists regarding the most appropriate surgical method. We analyzed the results of surgical fixation in cases of sternal fracture in order to identify which surgical method led to the best outcomes. Methods We retrospectively reviewed the medical records of patients with sternal fractures from December 2008 to December 2011, and found 19 patients who underwent open reduction and internal fixation of the sternum with a longitudinal plate (L-group) or a T-shaped plate (T-group). We investigated patients’ characteristics, clinical details regarding each case of chest trauma, the presence of other associated injuries, the type of open reduction and fixation, whether a combined operation was performed, and postoperative complications. Results Of the 19 patients, 10 patients (52.6%) were male, and their average age was 56.8 years (range, 32 to 82 years). Seven patients (36.8%) had isolated sternal fractures, while 12 (63.2%) had other associated injuries. Seven patients (36.8%) were in the L-group and 12 patients (63.2%) were in the T-group. Three patients in the L-group (42.9%) showed a loosening of the fixation. In all patients in the T-group, the fracture exhibited stable alignment. Conclusion Open reduction and internal fixation with a T-shaped plate in sternal fractures is a safer and more efficient treatment method than treatment with a longitudinal plate, especially in patients with a severely displaced sternum or anterior flail chest, than a longitudinal plate. PMID:27733996

  1. Closed treatment of condylar fractures by intermaxillary fixation with thermoforming plates.

    PubMed

    Terai, Haruhiko; Shimahara, Masashi

    2004-02-01

    We report a new intermaxillary fixation (IMF) method for condylar fractures using a thermoforming plate. Fifteen cases of condylar fracture were selected and thermoforming plates were applied. The patient's recover was uneventful in all 15 cases, and the period of IMF ranged from 7 to 17 days, (mean 12) for the following 7 days IMF was used only at night together with functional jaw training during the day. The outcome was good. IMF using a thermoforming plate may be a useful technique for selected condylar fractures.

  2. One size does not fit all: distal radioulnar joint dysfunction after volar locking plate fixation.

    PubMed

    Jones, Christopher W; Lawson, Richard D

    2014-02-01

    Background Fractures of the distal radius are among the most common injuries treated by orthopedic surgeons worldwide. Failure to restore distal radius alignment can lead to fracture malunion and poor clinical outcomes, including distal radioulnar joint (DRUJ) instability and limitation of motion. Case Description We present a unique case of DRUJ dysfunction following volar plate fixation of bilateral distal radius fractures and analyze the biomechanical causes of this complication. As a result of a relatively excessive tilt of the precontoured locking plate (in comparison to the patient's particular anatomy), the fracture on one side was "over-reduced," disrupting the biomechanics of the DRUJ, causing a supination block. Clinical Relevance Volar locking plates are not a panacea to all distal radius fractures. Plate selection and fixation technique must include consideration of patient anatomy. Robust plates offer the advantage of providing rigid fixation but can be difficult to contour when reconstructing normal anatomy. Restoration of patient-specific anatomy is crucial to the management of distal radius fractures.

  3. Pin guidance of reconstruction plate contour: an expanded role of external fixation.

    PubMed

    Jaquet, Yves; Higgins, Kevin M; Enepekides, Danny J

    2011-09-01

    This article presents a modification of intraoperative external fixation for mandibular reconstruction with free tissue flaps. This technique is indicated when preregistration of the reconstruction plate is not possible due to transmandibular tumor extension. Once standard external fixation has been carried out and prior to segmental mandibulectomy, additional pins are fixed to the connecting rod that delineate the mandibular contour in three-dimensional (3D) space. Following mandibulectomy, these pins allow accurate contouring of the reconstruction plate and improved restoration of mandibular contour, projection, and dental occlusion. A step-by-step description of the technique using models and intraoperative photos is presented. This method of mandibular reconstruction is a simple and time-effective alternative to intraoperative computer navigation and 3D modeling in select cases of oral carcinoma where tumor infiltration of the outer mandibular cortex precludes prebending of the reconstruction plates.

  4. Finite Element-Derived Surrogate Models of Locked Plate Fracture Fixation Biomechanics.

    PubMed

    Wee, Hwabok; Reid, J Spence; Chinchilli, Vernon M; Lewis, Gregory S

    2017-03-01

    Internal fixation of bone fractures using plates and screws involves many choices-implant type, material, sizes, and geometric configuration-made by the surgeon. These decisions can be important for providing adequate stability to promote healing and prevent implant mechanical failure. The purpose of this study was to develop mathematical models of the relationships between fracture fixation construct parameters and resulting 3D biomechanics, based on parametric computer simulations. Finite element models of hundreds of different locked plate fixation constructs for midshaft diaphyseal fractures were systematically assembled using custom algorithms, and axial, torsional, and bending loadings were simulated. Multivariate regression was used to fit response surface polynomial equations relating fixation design parameters to outputs including maximum implant stresses, axial and shear strain at the fracture site, and construct stiffness. Surrogate models with as little as three regressors showed good fitting (R (2) = 0.62-0.97). Inner working length was the strongest predictor of maximum plate and screw stresses, and a variety of quadratic and interaction terms influenced resulting biomechanics. The framework presented in this study can be applied to additional types of bone fractures to provide clinicians and implant designers with clinical insight, surgical optimization, and a comprehensive mathematical description of biomechanics.

  5. Finite element analysis of the stability of combined plate internal fixation in posterior wall fractures of acetabulum

    PubMed Central

    Liu, Xi-Ming; Pan, Chang-Wu; Wang, Guo-Dong; Cai, Xian-Hua; Chen, Lei; Meng, Cheng-Fei; Huang, Jin-Cheng

    2015-01-01

    Objective: This study aims to explore the mechanical stability of combined plate internal fixation in posterior wall fractures of the acetabulum. Methods: The fracture and internal fixation models were established in this study and they were divided into four kinds of internal fixation models, finite element analysis was performed. The four groups were 2 mini-plates and 1 reconstruction plate fixation (A), Reconstruction plate internal fixation group (B), 2 screws internal fixation group (C) and mini-plates internal fixation group (D). The displacement of each node was measured and evaluated. Results: There was no distortion in the geometric shape of the finite element model. The results of stress showed that it was less in the anterior pelvic ring and distributed uniform in labrum acetabulare; the stress was bigger in the upper and middle of sacroiliac joint and sciatic notch in sitting position. Conclusions: Combined plate internal fixation for posterior wall fractures of acetabular were stable and reliable, it is better than the other three methods. PMID:26550272

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

    PubMed Central

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

    2016-01-01

    Background: When primary fixation of proximal femoral fractures with implants fails, revision osteosynthesis may be challenging. Tracts of previous implants and remaining insufficient bone stock in the proximal femur pose unique problems for the treatment. Intramedullary implants like proximal femoral nail (PFN) or surface implants like Dynamic Condylar Screw (DCS) are few of the described implants for revision surgery. There is no evidence in the literature to choose one implant over the other. We used the reverse distal femur locking compression plate (LCP) of the contralateral side in such cases undergoing revision surgery. This implant has multiple options of fixation in proximal femur and its curvature along the length matches the anterior bow of the femur. We aimed to evaluate the efficacy of this implant in salvage situations. Materials and Methods: Twenty patients of failed primary proximal femoral fractures who underwent revision surgery with reverse distal femoral locking plate from February 2009 to November 2012 were included in this retrospective study. There were 18 subtrochanteric fractures and two ipsilateral femoral neck and shaft fractures, which exhibited delayed union or nonunion. The study included 14 males and six females. The mean patient age was 43.6 years (range 22–65 years) and mean followup period was 52.1 months (range 27–72 months). Delayed union was considered when clinical and radiological signs of union failed to progress at the end of four months from initial surgery. Results: All fractures exhibited union without any complications. Union was assessed clinically and radiologically. One case of ipsilateral femoral neck and shaft fracture required bone grafting at the second stage for delayed union of the femoral shaft fracture. Conclusions: Reverse distal femoral LCP of the contralateral side can be used as a salvage option for failed fixation of proximal femoral fractures exhibiting nonunion. PMID:27512218

  7. Fixation of multifragmentary patella fractures using a bilateral fixed-angle plate.

    PubMed

    Thelen, Simon; Betsch, Marcel; Schneppendahl, Johannes; Grassmann, Jan; Hakimi, Mohssen; Eichler, Christian; Windolf, Joachim; Wild, Michael

    2013-11-01

    This biomechanical study is the first to compare 3 fixation methods-bilateral fixed-angle plate, modified anterior tension wiring, and cannulated lag screws with anterior tension wiring-in multifragmentary distal patella fractures. A T-shaped 3-part fracture simulating a multifragmentary articular distal patella fracture (AO/OTA 34-C2.2) was created in 18 human cadaver knee specimens. Three groups were created using homogenous ages and bone mineral densities based on the fixation method received. Repetitive testing over 100 cycles was performed by moving the knee against gravity from 90° flexion to full extension. Failure was defined as fracture displacement greater than 2 mm. In all patellae using fixed-angle plates, an anatomical fracture reduction could be maintained throughout cyclic testing, whereas anterior tension wiring and lag screws with tension wiring showed significant fracture displacement after 100 cycles, with mean fracture gaps of 2.0±1.3 and 1.9±1.6 mm, respectively. The differences in fracture gaps between the fixed-angle plate group and the other 2 groups were statistically significant. In both groups using tension wiring, half of the constructs (3 of 6 in each group) failed due to a fracture displacement greater than 2 mm. The bilateral fixed-angle plate was the only fixation method that sustainably stabilized a multifragmentary articular distal patella fracture during cyclic loading when compared with modified anterior tension wiring and cannulated lag screws with anterior tension wiring.

  8. Complex AO type C3 distal femur fractures: Results after fixation with a lateral locked plate using modified swashbuckler approach

    PubMed Central

    Agrawal, Anuj; Kiyawat, Vivek

    2017-01-01

    Background: Complex AO type C3 fractures of the distal femur are challenging injuries, fraught with complications such as malunion and stiffness. We prospectively evaluated a consecutive series of patients with complex AO type C3 distal femur fractures to determine the clinicoradiological outcome after fixation with a single locked plate using modified swashbuckler approach. Materials and Methods: 12 patients with C3 type distal femur fractures treated with a lateral locked plate, using a modified swashbuckler approach, were included in the study. The extraarticular component was managed either by compression plating or bridge plating (transarticular approach and retrograde plate osteosynthesis) depending on the fracture pattern. Primary bone grafting was not done in any case. The clinical outcome at 1 year was determined using the Knee Society Score (KSS). The presence of any secondary osteoarthritis in the knee joint was noted at final followup. Results: All fractures united at a mean of 14.3 ± 4.7 weeks (range 6–26 weeks). There were no significant complications such as nonunion, deep infection, and implant failure. One of the patients underwent secondary bone grafting at 3 months. The mean range of motion of the knee was 120° ± 14.8° (range 105°–150°). Seven patients had excellent, three patients had good and two patients had a fair outcome according to the KSS at 1 year. At a mean followup of 17.6 months, three patients showed radiological evidence of secondary osteoarthritis of the knee joint. However, only one of these patients was symptomatic. Conclusion: The results of complex C3 type distal femur fractures, fixed with a single lateral locked plate using a modified swashbuckler approach, are encouraging, with a majority of patients achieving good to excellent outcome at 1 year. PMID:28216747

  9. Open Reduction and Volar Plate Fixation of Dorsally Displaced Distal Radius Fractures: A Prospective Study of Functional and Radiological Outcomes

    PubMed Central

    Sadasivan, Anand Kumar; Hegde, Anoop; Shetty, Ashwin

    2016-01-01

    Introduction The fractures of the distal radius have always posed a unique challenge to the orthopaedic fraternity. The complex ligamentous and bony anatomy offers a wide variety of fractures to be dealt with around this zone. Over the years these injuries have become common especially in the elderly age group as well as the implants and surgical techniques have improved. Aim To assess the radiological and functional outcome after fixation of intra-articular dorsally displaced distal radius fractures with open reduction and volar Locking Compression Plate fixation (LCP). To study the complications occurring with this technique. Materials and Methods A prospective study was conducted in the Department of Orthopaedics at ARS Hospital, Tirupur, Tamil Nadu, from June 2015 to June 2016. A total of 20 skeletally mature patients with Lidstrom class 2D and 2E fresh closed distal radius fractures were enrolled in the study. All the patients underwent open reduction with locking compression plating with titanium LCPs using the volar approach. The patients were reviewed regularly at three, six, 12 and 24 weeks. Final assessment of radiographic fracture union was done and scored as per the ‘Radiographic Scoring System to Evaluate Union of Distal Radius Fractures {Radius Union Scoring System (RUSS)}’ and the functional assessment of the wrist was done using the Mayo wrist score. The final results were tabulated and calculated statistically using ‘frequency and proportions’ and ‘Chi-square tests’ were used to assess the test of association. Results Of the 20 patients reviewed, one patient had excellent Mayo wrist score, five had good scores, 12 had satisfactory and two patients had poor results. Seven patients had a RUSS score less than five points and four patients had RUSS score of five points, four patients had six points, two patients had seven points and three patients had eight points. One patient was noted to have dorsal collapse of the fracture during the

  10. Human fixation detection model in video compressed domain based on Markov random field

    NASA Astrophysics Data System (ADS)

    Li, Yongjun; Li, Yunsong; Liu, Weijia; Hu, Jing; Ge, Chiru

    2017-01-01

    Recently, research on and applications of human fixation detection in video compressed domain have gained increasing attention. However, prediction accuracy and computational complexity still remain a challenge. This paper addresses the problem of compressed domain fixations detection in the videos based on residual discrete cosine transform coefficients norm (RDCN) and Markov random field (MRF). RDCN feature is directly extracted from the compressed video with partial decoding and is normalized. After spatial-temporal filtering, the normalized map [Smoothed RDCN (SRDCN) map] is taken to the MRF model, and the optimal binary label map is obtained. Based on the label map and the center saliency map, saliency enhancement and nonsaliency inhibition are done for the SRDCN map, and the final SRDCN-MRF salient map is obtained. Compared with the similar models, we enhance the available energy functions and introduce an energy function that indicates the positional information of the saliency. The procedure is advantageous for improving prediction accuracy and reducing computational complexity. The validation and comparison are made by several accuracy metrics on two ground truth datasets. Experimental results show that the proposed saliency detection model achieves superior performances over several state-of-the-art compressed-domain and pixel-domain algorithms on evaluation metrics. Computationally, our algorithm reduces 26% more computational complexity with comparison to similar algorithms.

  11. Salter-Harris II forearm fracture reduction and fixation using a buttress plate

    PubMed Central

    Barnes, Jonathan; Webb, Mark; Fearon, Paul v

    2014-01-01

    Distal radius fractures are common injuries in children. Those that affect the growth plate (physis) need to be managed carefully as inadequate management may lead to long-term deformity and a reduction in function. However, different management strategies all have drawbacks and controversy exists over how best to manage these cases. This is the case of a 13-year-old girl who presented with a Salter Harris II fracture, which was managed using a novel approach of utilising a T plate in a buttress mode to stabilise the fracture after anatomical reduction. This provided effective fracture fixation and should allow good bone healing without causing any iatrogenic growth plate damage and without fixing a plate across the physis, which may need removal in the future. PMID:24488665

  12. Plating versus intramedullary fixation for mid-shaft clavicle fractures: a systemic review and meta-analysis.

    PubMed

    Gao, Yan; Chen, Wei; Liu, Yue-Jv; Li, Xu; Wang, Hai-Li; Chen, Zhao-Yu

    2016-01-01

    Background. Plate fixation and intramedullary fixation are the most commonly used surgical treatment options for mid-shaft clavicle fractures; the latter method has demonstrated better performance in some studies. Objectives. Our aim was to critically review and summarize the literature comparing the outcomes of mid-shaft clavicle fracture treatment with plate fixation or intramedullary fixation to identify the better approach. Search Methods. Potential academic articles were identified from the Cochrane Library, MEDLINE (1966-2015.5), PubMed (1966-2015.5), EMBASE (1980-2015.5) and ScienceDirect (1966-2015.5). Gray studies were identified from the references of the included literature. Selection Criteria. Randomized controlled trials (RCTs) and non-RCTs comparing plate fixation and intramedullary fixation for mid-shaft clavicle fracture were included. Data Collection and Analysis. Two reviewers performed independent data abstraction. The I (2) statistic was used to assess heterogeneity. A fixed- or random-effects model was used for the meta-analysis. Results. Six RCTs and nine non-RCTs were retrieved, including 513 patients in the intramedullary fixation group and 521 patients in the plating group. No significant differences in terms of the union rate and shoulder function were found between the groups. Patients in the intramedullary fixation group had a shorter operative time, less blood loss, smaller wound size, and shorter union time than those in the plating group. With respect to complications, significant differences were identified for all complications and major complications (wound infection, nonunion, implant failures, transient brachial plexopathy, and pain after 6 months). Similar secondary complications (symptomatic hardware, hardware irritation, prominence, numbness, hypertrophic callus) were observed in both groups. Conclusions. Intramedullary fixation may be superior to plate fixation in the treatment of mid-shaft clavicle fractures, with similar

  13. The calcar screw in angular stable plate fixation of proximal humeral fractures - a case study

    PubMed Central

    2011-01-01

    Background With new minimally-invasive approaches for angular stable plate fixation of proximal humeral fractures, the need for the placement of oblique inferomedial screws ('calcar screw') has increasingly been discussed. The purpose of this study was to investigate the influence of calcar screws on secondary loss of reduction and on the occurrence of complications. Methods Patients with a proximal humeral fracture who underwent angular stable plate fixation between 01/2007 and 07/2009 were included. On AP views of the shoulder, the difference in height between humeral head and the proximal end of the plate were determined postoperatively and at follow-up. Additionally, the occurrence of complications was documented. Patients with calcar screws were assigned to group C+, patients without to group C-. Results Follow-up was possible in 60 patients (C+ 6.7 ± 5.6 M/C- 5.0 ± 2.8 M). Humeral head necrosis occurred in 6 (C+, 15.4%) and 3 (C-, 14.3%) cases. Cut-out of the proximal screws was observed in 3 (C+, 7.7%) and 1 (C-, 4.8%) cases. In each group, 1 patient showed delayed union. Implant failure or lesions of the axillary nerve were not observed. In 44 patients, true AP and Neer views were available to measure the head-plate distance. There was a significant loss of reduction in group C- (2.56 ± 2.65 mm) compared to C+ (0.77 ± 1.44 mm; p = 0.01). Conclusions The placement of calcar screws in the angular stable plate fixation of proximal humeral fractures is associated with less secondary loss of reduction by providing inferomedial support. An increased risk for complications could not be shown. PMID:21943090

  14. Assessment of Intra-articular Screw Penetration During Radial Head and Olecranon Locking Plate Fixation

    PubMed Central

    Dizdarevic, Ismar; Eden, Claire M.; Bengard, Matthew; Barron, O. Alton; Catalano, Louis W.; Glickel, Steven Z.

    2016-01-01

    Background: The purpose of this study is to evaluate the role of radiographic and clinical exams in predicting screw penetration into the proximal radioulnar joint and ulnohumeral joint during open reduction and internal fixation of the radial head and proximal ulna. Methods: Olecranon and radial head plates were applied to 15 cadaveric elbows. Screws were assessed for intra-articular joint penetration using both clinical exam and radiographic evaluation. Clinical exam consisted of evaluation for crepitus. Radiographs demonstrating screws positioned near the joint surface were evaluated for penetration by 3 fellowship trained hand surgeons. Elbows were disarticulated and screw prominence was determined and recorded using standardized calipers. The ability of clinical and radiographic exams to correctly predict a breach in the articular surface was determined by calculating sensitivity, specificity, and predictive values. Consideration was given to screw position. Results: The sensitivity of crepitus was 81.1% for screws in the radial head plate and 72.6% for screws in the olecranon plate. The sensitivity of radiographs was 72.4% for the screws in the radial head plate and 55.0% for screws in the olecranon plate. Correct radiographic assessment of penetration varied but position o-2 on the olecranon plate consistently resulted in the lowest sensitivity of 30.3%. Conclusions: The study evaluates sensitivity and specificity of clinical and radiographic means when assessing for articular penetration of screws during olecranon and radial head locking plate fixation. Certain screw locations are more difficult to evaluate than others and may go undetected by standard means of assessment used in a surgical setting. PMID:27418892

  15. Contact problems for a circular plate with sliding fixation at the end face

    NASA Astrophysics Data System (ADS)

    Bazarenko, N. A.

    2014-05-01

    Two mixed elasticity problems of punch indentation into a circular plate placed without clearance in a rigid cylindrical holder with smooth walls are considered. In the first problem, the plate lies without friction on a rigid base, and in the second problem, the plate is rigidly fixed to the base. The problems are solved by a method that was developed for bodies of finite dimensions and is based on the properties of closed systems of orthogonal functions. Each of the problems is reduced to two integral equations, namely, a Volterra integral equation of the first kind for the contact pressure function and a Fredholm integral equation of the first kind for the derivatives of the displacement of the plate upper surface outside the punch. The displacement function is sought as the sum of a trigonometric series and a power function with a root singularity. After truncation, the obtained illposed system of linear algebraic equation has a stable solution. A method for solving Volterra integral equations is given. The contact pressure distribution function and the dimensionless indentation force are determined. Examples of calculation of the plate interaction with the plane punch are given. Contact problems were earlier studied for a rectangle and a circular plate with a stress-free end both without taking account of their fixation [1, 2] and with regard for their fixation [3, 4]. The solution method described here was used to study the interaction of elastic hollow cylinder of finite length with a rigid bandage and a rigid insert [5, 6]. Other papers dealing with contact problems for bodies of finite dimensions, in particular, for a circular plate, should also be mentioned. In these papers, the problems under study were solved by the method of homogeneous solutions [7, 8] and by the method of coupled series-equations [9].

  16. Development of the Gliding Hole of the Dynamics Compression Plate

    NASA Astrophysics Data System (ADS)

    Salim, U. A.; Suyitno; Magetsari, R.; Mahardika, M.

    2017-02-01

    The gliding hole of the dynamics compression plate is designed to facilitate relative movement of pedicle screw during surgery application. The gliding hole shape is then geometrically complex. The gliding hole manufactured using machining processes used to employ ball-nose cutting tool. Then, production cost is expensive due to long production time. This study proposed to increase productivity of DCP products by introducing forming process (cold forming). The forming process used to involve any press tool devices. In the closed die forming press tool is designed with little allowance, then work-pieces is trapped in the mould after forming. Therefore, it is very important to determine hole geometry and dimensions of raw material in order to success on forming process. This study optimized the hole sizes with both geometry analytics and experiments. The success of the forming process was performed by increasing the holes size on the raw materials. The holes size need to be prepared is diameter of 5.5 mm with a length of 11.4 mm for the plate thickness 3 mm and diameter of 6 mm with a length of 12.5 mm for the plate thickness 4 mm.

  17. Comparison of outcome of tibial plafond fractures managed by hybrid external fixation versus two-stage management with final plate fixation

    PubMed Central

    Cisneros, Luis Natera; Gómez, Mireia; Alvarez, Carlos; Millán, Angélica; De Caso, Julio; Soria, Laura

    2016-01-01

    Background: Tibial platfond fractures are usually associated with massive swelling of the foot and ankle, as well as with open wounds. This swelling may cause significant decrease of the blood flow, so the state of the soft tissue is determinant for the surgical indication and the type of implant. This retrospective study compares the union times in cases of tibial plafond fractures managed with a hybrid external fixation as a definitive procedure versus those managed with a two stage strategy with final plate fixation. Materials and Methods: A retrospective study in a polytrauma referral hospital was performed between 2005 and 2011. Patients with a tibial plafond fracture, managed with a hybrid external fixation as a definitive procedure or managed with a two stage strategy with the final plate fixation were included in the study. Postoperative radiographs were evaluated by two senior surgeons. Fracture healing was defined as callus bridging of one cortex, seen on both lateral and anteroposterior X-ray. The clinical outcome was evaluated by means of 11 points Numerical Rating Scale for pain and The American Orthopedic Foot and Ankle Society ankle score, assessed at the last followup visit. Thirteen patients had been managed with a hybrid external fixation and 18 with a two-stage strategy with the final plate fixation. There were 14 males and 17 females with a mean age of 48 years (range 19–82 years). The mean followup was 24 months (range 24–70 months). Results: The mean time from surgery to weight bearing was 7 ± 6.36 days for the hybrid fixation group and 57.43 ± 15.46 days for the plate fixation group (P < 0.0001); and the mean time from fracture to radiological union was 133.82 ± 37.83) and 152.8 ± 72.33 days respectively (P = 0.560). Conclusion: Besides the differences between groups regarding the baseline characteristics of patients, the results of this study suggest that in cases of tibial plafond fractures, the management with a hybrid external

  18. Fixation of Intertrochanteric Valgus Osteotomy with T Plate in Treatment of Developmental Coxa Vara

    PubMed Central

    Khairy, Hosam Mohamed

    2016-01-01

    Background Although the valgus subtrochanteric osteotomy is considered as a standard surgical treatment for coxa vara, there is no consensus on the optimal method of fixation and osteotomy technique. Fixation of the osteotomy has been achieved by various methods including external fixation and internal fixation with pins and cerclage and a variety of plates. The aim of this study is the evaluation of the results of developmental coxa treated by Y intertrochanteric valgus osteotomy fixed with a T-buttress plate compared with other methods of fixation in the literature. Methods Eighteen corrective valgus intertrochanteric femoral osteotomies were performed in 18 patients (18 hips) for treatment of unilateral developmental coxa vara deformity and fixed with a T plate. There were 12 males and 6 females. The right hip was affected in 10 patients and the left hip in 8 patients. Clinically, patients were evaluated by Larson hip score. Radiographically, anteroposterior view of the pelvis and frog leg lateral views of the affected hip were taken preoperatively and compared with the findings at the final follow-up. Results The average follow-up was 29 months (range, 24 to 36 months). Clinical results showed improvement of the mean Larson hip score from 57.8 to 97.0 (p < 0.001). Radiological results showed that all osteotomies were completely united in 2.4 months (range, 2 to 3 months) with the achievement of the planned correction angle. The average correction of Hilgenreiner's epiphyseal angle improved from 78.2° to 27.8° (p < 0.001) at the final follow-up. The femoral neck shaft angle was improved from 93.7° to 129.9° (p < 0.001) at the final follow-up. Shortening of the affected limb was corrected from 2.8 cm to 1.3 cm (p < 0.001) at the last follow-up. No major serious complications were recorded in the present study. Conclusions Intertrochanteric valgus osteotomy of the proximal femur fixed with a T plate may be efficient for treatment of developmental coxa vara

  19. Biomechanical investigation of an alternative concept to angular stable plating using conventional fixation hardware

    PubMed Central

    2010-01-01

    Background Angle-stable locking plates have improved the surgical management of fractures. However, locking implants are costly and removal can be difficult. The aim of this in vitro study was to evaluate the biomechanical performance of a newly proposed crossed-screw concept ("Fence") utilizing conventional (non-locked) implants in comparison to conventional LC-DCP (limited contact dynamic compression plate) and LCP (locking compression plate) stabilization, in a human cadaveric diaphyseal gap model. Methods In eight pairs of human cadaveric femora, one femur per pair was randomly assigned to receive a Fence construct with either elevated or non-elevated plate, while the contralateral femur received either an LCP or LC-DCP instrumentation. Fracture gap motion and fatigue performance under cyclic loading was evaluated successively in axial compression and in torsion. Results were statistically compared in a pairwise setting. Results The elevated Fence constructs allowed significantly higher gap motion compared to the LCP instrumentations (axial compression: p ≤ 0.011, torsion p ≤ 0.015) but revealed similar performance under cyclic loading (p = 0.43). The Fence instrumentation with established bone-plate contact revealed larger fracture gap motion under axial compression compared to the conventional LC-DCP osteosynthesis (p ≤ 0.017). However, all contact Fence specimens survived the cyclic test, whereas all LC-DCP constructs failed early during torsion testing (p < 0.001). All failures occurred due to breakage of the screw heads. Conclusions Even though accentuated fracture gap motion became obvious, the "Fence" technique is considered an alternative to cost-intensive locking-head devices. The concept can be of interest in cases were angle-stable implants are unavailable and can lead to new strategies in implant design. PMID:20492707

  20. Locking plate fixation of distal femoral fractures is a challenging technique: a retrospective review

    PubMed Central

    Toro, Giuseppe; Calabrò, Giampiero; Toro, Antonio; de Sire, Alessandro; Iolascon, Giovanni

    2015-01-01

    Summary Distal femoral fractures have typically a bimodal occurrence: in young people due to a high-energy trauma and in older people related to a low-energy trauma. These fractures are associated to a very high morbidity and mortality in elderly. Distal femoral fractures might be treated with plates, intramedullary nails, external fixations, and prosthesis. However, difficulties in fracture healing and the rate of complications are important clinical issues. The purpose of this retrospective review was to present our experience in treatment of distal femoral fracture in a sample of older people in order to evaluate the technical pitfalls and strategies used to face up the fractures unsuccessfully treated with locking plates. We included people aged more than 65 years, with a diagnosis of distal femoral fracture, treated with locking plates. We considered ‘unsuccessfully treated’ the cases with healing problems or hardware failures. Of the 12 patients (9 females and 3 males; mean aged 68.75 ± 3.31 years) included, we observed 3 ‘unsuccessfully cases’, 2 due to nonunions and 1 due to an early hardware failure, all treated using a condylar blade plate with a bone graft. One patient obtained a complete fracture healing after 1 year and in the other cases there was a nonunion. We observed as most common technical pitfalls: inadequate plate lengthening, fracture bridging, and number of locking screws. The use of locking plates is an emerging technique to treat these fractures but it seems more challenging than expected. In literature there is a lack of evidences about the surgical management of distal femoral fractures that is still an important challenge for the orthopaedic surgeon that has to be able to use all the fixation devices available. PMID:27134634

  1. Enhancing fixation strength in periprosthetic femur fractures by orthogonal plating-A biomechanical study.

    PubMed

    Lenz, Mark; Stoffel, Karl; Gueorguiev, Boyko; Klos, Kajetan; Kielstein, Heike; Hofmann, Gunther O

    2016-04-01

    Orthogonal plate osteosynthesis enhances fixation stability in periprosthetic femur fractures. Another option are locking attachment plates (LAP) allowing bicortical locking screw placement lateral to the prosthesis stem. Stability of lateral plate osteosynthesis with two LAP (2LAP) was compared to anterolateral orthogonal plate osteosynthesis (OP) with one LAP in a periprosthetic femur fracture model. In six pairs of fresh frozen human femora with cemented Charnley hip prosthesis, a transverse osteotomy was set distal to the tip of the prosthesis simulating a Vancouver type B1 fracture. Each pair was instrumented using a plate tensioner with either one lateral plate and two LAP, or two orthogonal anterolateral plates and one LAP. Stiffness was determined in a four-point-bending test prior to cyclic testing (2Hz) with physiologic profile and progressively increasing load up to catastrophic construct failure. Paired t-test and Wilcoxon-signed-rank test were used for statistical evaluation at a level of significance p = 0.05. The OP construct exhibited a significantly higher number of cycles and load to failure (39,627 cycles ± 4,056; 4,463 N ± 906) compared to the 2LAP construct (32,927 cycles ± 3,487; 3,793 N ± 849), p < 0.01. Mediolateral bending and torsional stiffness of the OP (1610 N/mm ± 249; 16.9 Nm/mm ± 6.3) were significantly higher compared to 2 LAP (1077 N/mm ± 189; 12.1 Nm/mm ± 3.9), p = 0.03 for both comparisons. Orthogonal plate osteosynthesis is a valuable option in periprosthetic fracture surgery, offering increased stability compared to a single lateral plate fixed with two LAP.

  2. Are chest compressions safe for the patient reconstructed with sternal plates? Evaluating the safety of cardiopulmonary resuscitation using a human cadaveric model

    PubMed Central

    2010-01-01

    Background Plate and screw fixation is a recent addition to the sternal wound treatment armamentarium. Patients undergoing cardiac and major vascular surgery have a higher risk of postoperative arrest than other elective patients. Those who undergo sternotomy for either cardiac or major vascular procedures are at a higher risk of postoperative arrest. Sternal plate design allows quick access to the mediastinum facilitating open cardiac massage, but chest compressions are the mainstay of re-establishing cardiac output in the event of arrest. The response of sternal plates and the chest wall to compressions when plated has not been studied. The safety of performing this maneuver is unknown. This study intends to demonstrate compressions are safe after sternal plating. Methods We investigated the effect of chest compressions on the plated sternum using a human cadaveric model. Cadavers were plated, an arrest was simulated, and an experienced physician performed a simulated resuscitation. Intrathoracic pressure was monitored throughout to ensure the plates encountered an appropriate degree of force. The hardware and viscera were evaluated for failure and trauma respectively. Results No hardware failure or obvious visceral trauma was observed. Rib fractures beyond the boundaries of the plates were noted but the incidence was comparable to control and to the fracture incidence after resuscitation previously cited in the literature. Conclusions From this work we believe chest compressions are safe for the patient with sternal plates when proper plating technique is used. We advocate the use of this life-saving maneuver as part of an ACLS resuscitation in the event of an arrest for rapidly re-establishing circulation. PMID:20718981

  3. PERPENDICULAR DOUBLE-PLATE FIXATION WITH LOCKING SYSTEM FOR ACROMION PEDICLE FRACTURE

    PubMed Central

    Zhu, Junkun; Pan, Zhijun; Zheng, Rongzong; Lan, Shuhua

    2016-01-01

    Objective : To describe the surgical technique and preliminary clinical outcomes in a series of open reduction internal fixation of basal acromion process fractures applying a double-plating technique. Methods : Nine consecutive patients, mean age 33.4 years old (range, 23-61 years old) with unilateral acromion fracture (Type 3 AO/OTA) with more than 1cm displacement who underwent fixation utilizing a locked double-plating technique, were evaluated on average at 7.8 months (range, 3-15 months) for outcomes related to pain, shoulder function, and surgical complications. Results : Eight patients recovered with complete radiographic union and favorable shoulder function. One case failed to be fully evaluated for more than 3 months follow-up. The overall scores of Constant, Shoulder Pain and Disability Index (SPADI) and DASH for the eight patients reviewed were 91.9± 6.31, 3.11± 3.79 and 5.2± 6.35, respectively. No post-operative infection or surgical hardware irritation was identified at final follow-up of these eight patients. Conclusion : While more evidence is needed to justify its advantages over traditional implants, perpendicular double-plate with a locking system may be indicated for acromion pedicle fracture treatment, since it performed well for fracture healing and joint function rehabilitation. Level of Evidence IV, Therapeutic Study. PMID:26981047

  4. Patient-tailored plate for bone fixation and accurate 3D positioning in corrective osteotomy.

    PubMed

    Dobbe, J G G; Vroemen, J C; Strackee, S D; Streekstra, G J

    2013-02-01

    A bone fracture may lead to malunion of bone segments, which gives discomfort to the patient and may lead to chronic pain, reduced function and finally to early osteoarthritis. Corrective osteotomy is a treatment option to realign the bone segments. In this procedure, the surgeon tries to improve alignment by cutting the bone at, or near, the fracture location and fixates the bone segments in an improved position, using a plate and screws. Three-dimensional positioning is very complex and difficult to plan, perform and evaluate using standard 2D fluoroscopy imaging. This study introduces a new technique that uses preoperative 3D imaging to plan positioning and design a patient-tailored fixation plate that only fits in one way and realigns the bone segments as planned. The method is evaluated using artificial bones and renders realignment highly accurate and very reproducible (d(err) < 1.2 ± 0.8 mm and φ(err) < 1.8° ± 2.1°). Application of a patient-tailored plate is expected to be of great value for future corrective osteotomy surgeries.

  5. Early breakage of a titanium volar locking plate for fixation of a distal radius fracture: case report.

    PubMed

    Yukata, Kiminori; Doi, Kazuteru; Hattori, Yasunori; Sakamoto, Soutetsu

    2009-01-01

    This report presents a case demonstrating the early breakage of a titanium volar locking plate implanted for internal fixation of a dorsally displaced distal radius fracture in which the dorsal cortex was severely comminuted. Careful selection of the proper plate and appropriate surgical technique and postoperative management are necessary to avoid this complication.

  6. Simplified laser-driven flyer plates for shock compression science

    SciTech Connect

    Brown, Kathryn E.; Shaw, William L.; Zheng Xianxu; Dlott, Dana D.

    2012-10-15

    We describe a simplified system of laser-driven flyer plates for shock compression science and shock spectroscopy. We used commercially available one-box Nd:YAG lasers and beam homogenization solutions to create two launch systems, one based on a smaller (400 mJ) YAG laser and an inexpensive diffusive optic, and one based on a larger (2500 mJ) laser and a diffractive beam homogenizer. The flyer launch, flight, and impact processes were characterized by an 8 GHz fiberoptic photon Doppler velocimeter. We investigated effects of different substrates, adhesives, absorbers, ablative layers, and punching out disks from continuous foils versus fabricating individual foil disks, and found that a simple metal foil epoxied to a glass window was satisfactory in almost all cases. Our simplified system launched flyer plates with velocities up to 4.5 km s{sup -1} and kinetic energies up to 250 mJ that can drive sustained steady shocks for up to 25 ns. The factor that limits these velocities and energies is the laser fluence that can be transmitted through the glass substrate to the flyer surface without optical damage. Methods to increase this transmission are discussed. Reproducible flyer launches were demonstrated with velocity variations of 0.06% and impact time variations of 1 ns. The usefulness of this flyer plate system is demonstrated by Hugoniot equation of state measurements of a polymer film, emission spectroscopy of a dye embedded in the polymer, and impact initiation and emission spectroscopy of a reactive material consisting of nanoscopic fuel and oxidizer particles.

  7. Simplified laser-driven flyer plates for shock compression science.

    PubMed

    Brown, Kathryn E; Shaw, William L; Zheng, Xianxu; Dlott, Dana D

    2012-10-01

    We describe a simplified system of laser-driven flyer plates for shock compression science and shock spectroscopy. We used commercially available one-box Nd:YAG lasers and beam homogenization solutions to create two launch systems, one based on a smaller (400 mJ) YAG laser and an inexpensive diffusive optic, and one based on a larger (2500 mJ) laser and a diffractive beam homogenizer. The flyer launch, flight, and impact processes were characterized by an 8 GHz fiberoptic photon Doppler velocimeter. We investigated effects of different substrates, adhesives, absorbers, ablative layers, and punching out disks from continuous foils versus fabricating individual foil disks, and found that a simple metal foil epoxied to a glass window was satisfactory in almost all cases. Our simplified system launched flyer plates with velocities up to 4.5 km s(-1) and kinetic energies up to 250 mJ that can drive sustained steady shocks for up to 25 ns. The factor that limits these velocities and energies is the laser fluence that can be transmitted through the glass substrate to the flyer surface without optical damage. Methods to increase this transmission are discussed. Reproducible flyer launches were demonstrated with velocity variations of 0.06% and impact time variations of 1 ns. The usefulness of this flyer plate system is demonstrated by Hugoniot equation of state measurements of a polymer film, emission spectroscopy of a dye embedded in the polymer, and impact initiation and emission spectroscopy of a reactive material consisting of nanoscopic fuel and oxidizer particles.

  8. Simplified laser-driven flyer plates for shock compression science

    NASA Astrophysics Data System (ADS)

    Brown, Kathryn E.; Shaw, William L.; Zheng, Xianxu; Dlott, Dana D.

    2012-10-01

    We describe a simplified system of laser-driven flyer plates for shock compression science and shock spectroscopy. We used commercially available one-box Nd:YAG lasers and beam homogenization solutions to create two launch systems, one based on a smaller (400 mJ) YAG laser and an inexpensive diffusive optic, and one based on a larger (2500 mJ) laser and a diffractive beam homogenizer. The flyer launch, flight, and impact processes were characterized by an 8 GHz fiberoptic photon Doppler velocimeter. We investigated effects of different substrates, adhesives, absorbers, ablative layers, and punching out disks from continuous foils versus fabricating individual foil disks, and found that a simple metal foil epoxied to a glass window was satisfactory in almost all cases. Our simplified system launched flyer plates with velocities up to 4.5 km s-1 and kinetic energies up to 250 mJ that can drive sustained steady shocks for up to 25 ns. The factor that limits these velocities and energies is the laser fluence that can be transmitted through the glass substrate to the flyer surface without optical damage. Methods to increase this transmission are discussed. Reproducible flyer launches were demonstrated with velocity variations of 0.06% and impact time variations of 1 ns. The usefulness of this flyer plate system is demonstrated by Hugoniot equation of state measurements of a polymer film, emission spectroscopy of a dye embedded in the polymer, and impact initiation and emission spectroscopy of a reactive material consisting of nanoscopic fuel and oxidizer particles.

  9. Open Reduction and Internal Fixation of Displaced Calcaneum, Intra-Articular Fractures by Locking Calcaneal Plate

    PubMed Central

    Santosha; Singh, Arambam Mahendra; Waikhom, Sanjib; Pakhrin, Vishal; Mukherjee, Sagnik; Debbarma, Rajkumar; Prashant, Prabhu Shrinivas

    2016-01-01

    Introduction Calcaneal fractures constitute the most common fractures in hindfoot. Lots of controversies exist in the management of calcaneal fractures but now-a-days, it is preferable to perform open reduction and internal fixation and early mobilizatation. Aim To evaluate the functional outcome after open reduction and internal fixation of displaced intra-articular fractures of the calcaneum by locking calcaneal plate. Materials and Methods The study was conducted in the Department of Orthopaedic Surgery from September 2013 to April 2016. Thirty intra-articular fractures of the calcaneum were treated by locking calcaneal plate. Patients were followed up for a period of 24 months. Bohler’s angle was measured in preoperative, immediate Post-operative period and after 2 years, follow-up was compared. Results were evaluated according to American Orthopaedic Foot and Ankle Society (AOFAS) Score. Results After 24 months of follow-up, all 24 patients were available for evaluation. Radiological union was achieved in a mean time of 12.5 weeks. Mean duration of hospital stay was 21 days. Bohler’s angle was significantly higher after 2 years of follow-up when compared with preoperative x-ray. According to the AOFAS, Ankle–Hind foot Scale outcome score results were excellent in 43.3% of the patients, good in 33.3%, fair in 10%, and poor in 13.3% of patients. The mean AOFAS score was 79.9 (Range 49-96). Conclusion Open reduction and internal fixation of intra-articular fractures of the calcaneum with locking calcaneal plate gives good results. Maintenance of calcaneal height and Bohler’s angle helps to decrease the incidence of subtalar arthritis. PMID:28208957

  10. Managing Vancouver B1 fractures by cerclage system compared to locking plate fixation - a biomechanical study.

    PubMed

    Gordon, Katharina; Winkler, Martin; Hofstädter, Thomas; Dorn, Ulrich; Augat, Peter

    2016-06-01

    With increasing life expectancy and number of total hip arthroplasties (THA), the need for revision surgery is increasing too. The aim of this study was to evaluate the optimal fracture treatment for a clinically characteristic Vancouver B1 fracture. We hypothesized that locking plate fixation has biomechanical advantages over fixation with a simple cerclage system. Additionally, we hypothesized that removal of the primary short stem and revision with a long stem would show biomechanical benefit. The biomechanical testing was performed with a static and a dynamic loading protocol on twenty 4th Generation sawbones. These were divided into four different groups (n = 5 each). In group 1, the primary uncemented short stem remained and the fracture was stabilized with a locking plate. In group 2, the primary stem remained and the fracture was stabilized with a cerclage stabilization system containing two stabilizers and four cerclages. In group 3, the primary stem was replaced by an uncemented long revision stem and the fracture was fixed with a locking plate. In group 4, the short stem was replaced by a long revision stem and the fracture was fixed with the cerclage system. Static testing revealed that the revision of the short stem with the long stem caused a 2-fold (p < 0.001, ANOVA) increase of axial stiffness. In dynamic testing, the number of cycles to failure was 4 times (p < 0.001, ANOVA) higher with the long revision stem. Compared to locked plating cerclage wiring demonstrated a 26% more cycles to failure (p = 0.031, ANOVA). The load to failure was 91% larger (p < 0.001, ANOVA) with the long revision stem and 11% smaller with locked plating (p < 0.001, ANOVA). In conclusion, the present biomechanical study indicates that periprosthetic Vancouver B1 fractures can be sufficiently fixed by simple cerclage systems. Revision with a long replacement stem provides a superior mechanical stability regardless of type of osteosynthesis fixation and is therefore a viable

  11. Radiological Outcomes of Distal Radius Fractures Managed with 2.7mm Volar Locking Plate Fixation-A Retrospective Analysis

    PubMed Central

    Kotian, Prem; Mudiganty, Srikanth; Annappa, Rajendra

    2017-01-01

    Introduction Distal radius fractures accounts for around 15% of all fractures diagnosed and treated in the emergency rooms. These fractures usually result secondary to high velocity injury such as a motor vehicle accident or fall on an out stretched hand. In the elderly, it is a common fragility fracture. Volar Locking Compression Plates (LCP) is effective devices for fixation of the distal radius fractures. There is a lacuna with regard to literature on the 2.7 mm volar LCP and the current study retrospectively assesses the postoperative radiological outcomes. Aim To measure the radiological outcomes in patients with displaced distal radius fractures managed with 2.7 mm volar LCP fixation using Sarmiento’s Modification of Lindstorm Criteria. Materials and Methods A retrospective study was conducted in the Department of Orthopaedic Surgery at Kasturba Medical College Allied Hospitals, Mangalore from May 2014 to July 2016. All displaced distal radius fractures of skeletally mature patients who underwent volar locking plate fixation between May 2014 to July 2016 and follow up with X-rays at six weeks and three months were included as part of the study. The study comprised of 20 patients and fractures were classified using the AO and Melone’s classification systems. The radiological outcome was scored based on Sarmiento’s Modification of Lindstorm Criteria. Results Post operative check X-rays were analysed at immediate post operative, six weeks and three months. The mean immediate post operative radial shortening, decrease in radial deviation and loss of palmar tilt were 4.08±2.23, 5.91±4.01and 4.11±3.29 respectively. The corresponding values at last follow up were 4.71±2.31, 7.9±5.13 and 4.91±3.32 respectively. No statistically significant difference (p=0.930;874;716) in radial shortening, decrease in palmar angulation and loss of radial deviation was seen till the final follow up. Sarmiento’s Modification of Lindstorm Criteria showed a good

  12. Percutaneous fixation with Kirschner wires versus volar locking plate fixation in adults with dorsally displaced fracture of distal radius: randomised controlled trial

    PubMed Central

    Achten, Juul; Parsons, Nick R; Rangan, Amar; Griffin, Damian; Tubeuf, Sandy; Lamb, Sarah E

    2014-01-01

    Objectives To compare the clinical effectiveness of Kirschner wire fixation with locking plate fixation for patients with a dorsally displaced fracture of the distal radius. Design A multicentre two arm parallel group assessor blind randomised controlled trial with 1:1 treatment allocation. Setting 18 trauma centres in the United Kingdom. Participants 461 adults with a dorsally displaced fracture of the distal radius within 3 cm of the radiocarpal joint that required surgical fixation. Patients were excluded if the surgeon thought that the surface of the wrist joint was so badly displaced it required open reduction. Interventions Kirschner wire fixation: wires are passed through the skin over the dorsal aspect of the distal radius and into the bone to hold the fracture in the correct anatomical position. Locking plate fixation: a locking plate is applied through an incision over the volar (palm) aspect of the wrist and secured to the bone with fixed angle locking screws. Main outcome measures Primary outcome measure: validated patient rated wrist evaluation (PRWE). This rates wrist function in two (equally weighted) sections concerning the patient’s experience of pain and disability to give a score out of 100. Secondary outcomes: disabilities of arm, shoulder, and hand (DASH) score, the EuroQol (EQ-5D), and complications related to the surgery. Results The baseline characteristics of the two groups were well balanced, and over 90% of patients completed follow-up. The wrist function of both groups of patients improved by 12 months. There was no clinically relevant difference in the patient rated wrist score at three, six, or 12 months (difference in favour of the plate group was −1.3, 95% confidence interval −4.5 to 1.8; P=0.40). Nor was there a clinically relevant difference in health related quality of life or the number of complications in each group. Conclusions Contrary to the existing literature, and against the rapidly increasing use of locking plate

  13. Sternal closure by rigid plate fixation in off-pump coronary artery bypass grafting: a comparative study.

    PubMed

    Matsuyama, Katsuhiko; Kuinose, Masahiko; Koizumi, Nobusato; Iwasaki, Tomoaki; Toguchi, Kayo; Ogino, Hitoshi

    2016-06-01

    Sternal instability or dehiscence results in serious sternal wound infection. We sought to assess the early outcomes with such a plating system for sternal closure in comparison to the conventional wiring technique in off-pump coronary artery bypass grafting (CABG). Patients who underwent off-pump CABG were enrolled. Thirty-one patients received plate sternal fixation. A total of 64 patients who underwent off-pump CABG by a single surgeon at our hospital from July 2013 to December 2014 were enrolled. Thirty-one patients received plate sternal fixation (Plate group), while 33 received conventional wire closure (Wire group). The early outcomes, including the pain score and analgesic usage count were compared. Dietary intake was also recorded to assess the duration of appetite loss. At discharge, the largest sternal displacement was measured on computed tomography. In the Plate group, the pain scores were significantly lower on post-operative day 5-8 and POD 9-12 from those in the Wire group. The analgesic usage count on POD 9-12 was significantly lower in the Plate group. The duration of appetite loss and hospital stay was significantly shorter in the Plate group. The displacement in both the anterior-posterior and lateral directions was significantly smaller in the Plate group. Sternal closure by rigid plate fixation contributes to a more rapid post-operative recovery through reduced pain.

  14. Mini hook plate fixation for palmar fracture-dislocation of the proximal interphalangeal joint.

    PubMed

    Komura, Shingo; Yokoi, Tatsuo; Nonomura, Hidehiko

    2011-04-01

    Fracture-dislocations of the proximal interphalangeal joint are challenging to treat, since it is difficult to achieve both rigid fixation and early joint motion simultaneously. Palmar fracture-dislocations of the proximal interphalangeal joint are less frequent injuries and a small number of treatment methods have been reported. We describe here a patient with a chronic palmar fracture-dislocation of the proximal interphalangeal joint, who was treated with a new surgical technique. In the surgery, a mini hook plate that was made by adapting a 1.5 mm AO hand modular system straight plate was used. Despite the thinness of the fragment, rigid fixation was achieved, resulting in early active motion. At final follow up, the active ranges of motion were 0°-100° at the proximal and 0°-80° at the distal interphalangeal joint, and there were no complications. This technique may become a useful surgical method to treat palmar fracture-dislocations of the proximal interphalangeal joint.

  15. Plate selection for fixation of extra-articular distal humerus fractures: a biomechanical comparison of three different implants.

    PubMed

    Scolaro, John A; Hsu, Jason E; Svach, David J; Mehta, Samir

    2014-12-01

    Operative fixation of extra-articular distal humerus using a single posterolateral column plate has been described but the biomechanical properties or limits of this technique is undefined. The purpose of this study was to evaluate the mechanical properties of distal humerus fracture fixation using three standard fixation constructs. Two equal groups were created from forty sawbones humeri. Osteotomies were created at 80mm or 50mm from the tip of the trochlea. In the proximal osteotomy group, sawbones were fixed with an 8-hole 3.5mm LCP or with a 6-hole posterolateral plate. In the distal group, sawbones were fixed with 9-hole medial and lateral 3.5mm distal humerus plates and ten sawbones were fixed with a 6-hole posterolateral plate. Biomechanical testing was performed using a servohydraulic testing machine. Testing in extension as well as internal and external rotation was performed. Destructive testing was also performed with failure being defined as hardware pullout, sawbone failure or cortical contact at the osteotomy. In the proximal osteotomy group, the average bending stiffness and torsional stiffness was significantly greater with the posterolateral plate than with the 3.5mm LCP. In the distal osteotomy group, the average bending stiffness and torsional stiffness was significantly greater with the posterolateral plate than the 3.5mm LCP. In extension testing, the yield strength was significantly greater with the posterolateral plate in the proximal osteotomy specimens, and the dual plating construct in the distal osteotomy specimens. The yield strength of specimens in axial torsion was significantly greater with the posterolateral plate in the proximal osteotomy specimens, and the dual plating construct in the distal osteotomy specimens. Limited biomechanical data to support the use of a pre-contoured posterolateral distal humerus LCP for fixation of extra-articular distal humerus exists. We have found that this implant provided significantly greater

  16. [Management of Odontoid Fractures with Compression Screw and Anterior Transarticular Screw Fixation in Elderly Patients].

    PubMed

    Kočiš, J; Kelbl, M; Veselý, R; Kočiš, T

    2017-01-01

    PURPOSE OF THE STUDY In the management of dens axis fractures in patients older than 65 years of age the posterior approach is preferred due to osteoporosis and the risk of a failure of anterior osteosynthesis. The posterior approach, however, is associated with a higher incidence of complications. A combination of anterior transarticular fixation of C1/2 (ATS) with compression osteosynthesis of dens axis significantly increases the stability of osteosynthesis. MATERIAL AND METHODS In the period from 2009 to 2015 our hospital admitted 13 patients older than 65 years of age with a diagnosed type III dens axis fracture based on AO classification. 8 patients sustained a dens axis fracture combined with a stable atlas fracture. The cohort consisted of 13 women aged 67 to 90 years, with the mean age of 82.3 years. None of the female patients were affected neurologically. The dens axis fracture was treated by anterior approach. Once the screw was inserted in the dens axis, two more screws were added, the entrance points of those screws were medial and lateral to the odontoid screw and direction was divergently via C1/2 joints in order to reinforce stability. The patients were monitored at 6-week, 3-, 6- and 12-month follow-ups. Bone healing was confirmed by CT scan. RESULTS No complications were recorded during the surgery in any of the 13 patients. In one female patient the stabilization failed in the early postoperative period. A reoperation from anterior approach with the use of the same method was necessary. In eleven patients bone healing occurred after 6 to 12 months. In two patients pseudoarthrosis was formed with no clinical symptoms. No neurological deterioration or a patient s death was reported in the monitored period within 12 months after the treatment. DISCUSSION Where dens axis fractures in elderly patients are managed operatively, the posterior approach and transarticular fixation of C1/2 with sublaminar loop are preferred. This procedure is considered

  17. Does plugging unused combination screw holes improve the fatigue life of fixation with locking plates in comminuted supracondylar fractures of the femur?

    PubMed

    Firoozabadi, R; McDonald, E; Nguyen, T-Q; Buckley, J M; Kandemir, U

    2012-02-01

    Filling the empty holes in peri-articular locking plates may improve the fatigue strength of the fixation. The purpose of this in vitro study was to investigate the effect of plugging the unused holes on the fatigue life of peri-articular distal femoral plates used to fix a comminuted supracondylar fracture model. A locking/compression plate was applied to 33 synthetic femurs and then a 6 cm metaphyseal defect was created (AO Type 33-A3). The specimens were then divided into three groups: unplugged, plugged with locking screw only and fully plugged holes. They were then tested using a stepwise or run-out fatigue protocol, each applying cyclic physiological multiaxial loads. All specimens in the stepwise group failed at the 770 N load level. The mean number of cycles to failure for the stepwise specimen was 25,500 cycles (SD 1500), 28,800 cycles (SD 6300), and 26,400 cycles (SD 2300) cycles for the unplugged, screw only and fully plugged configurations, respectively (p = 0.16). The mean number of cycles to failure for the run-out specimens was 42,800 cycles (SD 10,700), 36,000 cycles (SD 7200), and 36,600 cycles (SD 10,000) for the unplugged, screw only and fully plugged configurations, respectively (p = 0.50). There were also no differences in axial or torsional stiffness between the constructs. The failures were through the screw holes at the level of comminution. In conclusion, filling the empty combination locking/compression holes in peri-articular distal femur locking plates at the level of supracondylar comminution does not increase the fatigue life of the fixation in a comminuted supracondylar femoral fracture model (AO 33-A3) with a 6 cm gap.

  18. A comparison of reversed locking compression-distal femoral plates and blade plates in osteotomies for young adult hip pathology.

    PubMed

    MacLean, Simon B M; Evans, Scott; O'Hara, John N

    2013-01-01

    The aim of this study was to compare fixation of proximal femoral osteotomies using reverse contralateral LCP-Distal Femoral Plates (LCP-DF) with the more traditional blade plate technique. This was a retrospective review over six years of a single surgeon's practice within a tertiary orthopaedic unit. Patient demographics were collected, along with indication for surgery. Radiological outcomes, fixation failures and the need for revision surgery were recorded. Forty-six patients were identified; 23 patients in the LCP-DF plate group (7 females, 16 males. Mean age 18.3 years old) and 23 patients in the blade plate group (6 females, 17 males. Mean age 19.1 years old). The patients' presenting conditions were; 26 Perthes'; eight hip dysplasia; 11 slipped capital femoral epiphysis; one fibrous dysplasia. Osteotomy type included; 13 Double osteotomy, 11 Imhauser; 13 pure valgus; eight valgus + rotation; There was one revision for implant failure in the LCP-DF group. In the blade plate group, there were four implant failures--three requiring revision operations (p = 0.155). In the LCP-DF group the mean neck-shaft angle difference compared to the contralateral side (if normal) or 135 degrees (if abnormal) was 0.58°. In the condylar plate group the mean difference was 4.37°. The use of a contralateral LCP-DF plate in the reverse contralateral position to stabilise proximal femoral osteotomies in our cohort confers advantages over blade plate technology. We have found that the plate is stiffer, is easier to use and provides increased screw placement options over standard proximal femoral locking plates.

  19. Minimally-invasive internal fixation of extra-articular distal femur fractures using a locking plate: tricks of the trade.

    PubMed

    Ehlinger, M; Adam, P; Abane, L; Arlettaz, Y; Bonnomet, F

    2011-04-01

    Fractures of the distal femur are rare and occur in two distinct population categories: young patients after high energy traumas and elderly patients who fall from their full height, and often carry severe co-morbidities making especially difficult to manage theses complex injuries. In elderly patients the potential complications are numerous including infection, non-union and frequent function deterioration. We present a technique of minimally invasive internal fixation of the distal extra-articular femur using a locking plate and present the tricks of the trade to obtain successful reduction and achieve union. The hardware used includes plate fixation with a large fragment locking screw. This minimally invasive surgery combines stability of the internal fixation device with the principles of closed surgery, allowing early mobilization and immediate weight bearing to warrant good functional recovery.

  20. Optimal Positioning for Volar Plate Fixation of a Distal Radius Fracture: Determining the Distal Dorsal Cortical Distance.

    PubMed

    Vosbikian, Michael M; Ketonis, Constantinos; Huang, Ronald; Ilyas, Asif M

    2016-01-01

    Distal radius fractures are currently among the most common fractures of the musculoskeletal system. With a population that is living longer, being more active, and the increasing incidence of osteoporosis, these injuries will continue to become increasingly prevalent. When operative fixation is indicated, the volar locking plate has recently become the treatment of choice. However, despite its success, suboptimal position of the volar locking plate can still result in radiographic loss of reduction. The distal dorsal cortical distance is being introduced as an intraoperative radiographic tool to help optimize plate position and minimize late loss of fracture reduction.

  1. Postbuckling behavior of longitudinally compressed orthotropic plates with three-dimensional flexibility

    NASA Technical Reports Server (NTRS)

    Stein, M.; Bains, N. J. C.

    1986-01-01

    Postbuckling results for the average longitudinal compressive stress vs applied displacement are obtained for aluminum (isotropic), aluminum/epoxy (quasi-isotropic), and 45-deg graphite/epoxy (orthotropic) plates using classical (Kirchhoff) and conventional transverse shearing theories. An analysis of the results obtained shows that, in the postbuckling range, the classical theory cannot provide reasonably accurate results even for thin plates.

  2. Strength of Rectangular Flat Plates Under Edge Compression

    NASA Technical Reports Server (NTRS)

    Schuman, Louis; Back, Goldie

    1931-01-01

    Flat rectangular plates of duralumin, stainless iron, monel metal, and nickel were tested under loads applied at two opposite edges and acting in the plane of the plate. The edges parallel to the direction of loading were supported in V grooves. The plates were all 24 inches long and varied in width from 4 to 24 inches by steps of 4 inches, and in thickness from 0.015 to 0.095 inch by steps of approximately 0.015 inch. There were also a few 1, 2, 3, and 6 inch wide specimens. The loads were applied in the testing machine at the center of a bar which rested along the top of the plate. Load was applied until the plate failed to take any more load. The tests show that the loads carried by the plates generally reached a maximum for the 8 or 12 inch width and that there was relatively small drop in load for the greater widths. Deflection and set measurement perpendicular to the plane of the plate were taken and the form of the buckle determined. The number of buckles were found to correspond in general to that predicted by the theory of buckling of a plate uniformly loaded at two opposite edges and simply supported at the edges.

  3. A Biomechanical Comparison of Locking Versus Conventional Plate Fixation for Distal Fibula Fractures in Trimalleolar Ankle Injuries.

    PubMed

    Nguyentat, Annie; Camisa, William; Patel, Sandeep; Lagaay, Pieter

    2016-01-01

    Previous biomechanical studies have advocated the use of locking plates for isolated distal fibula fractures in osteoporotic bone. Complex rotational ankle injuries involve an increased number of fractures, which can result in instability, potentially requiring the same fixed angle properties afforded by locking plates. However, the mechanical indication for locking plate technology has not been tested in this fracture model. The purpose of the present study was to compare the biomechanical properties of locking and conventional plate fixation for distal fibula fractures in trimalleolar ankle injuries. Fourteen (7 matched pairs) fresh-frozen cadaver leg specimens were used. The bone mineral density of each was obtained using dual x-ray absorptiometry scans. The fracture model simulated an OTA 44-B3.3 fracture. The syndesmosis was not disrupted. Each fracture was fixated in the same fashion, except for the distal fibula plate construct: locking (n = 7) and one-third tubular (n = 7). The specimens underwent axial and torsional cyclic loading, followed by torsional loading to failure. No statistically significant differences were found between the locking and conventional plate constructs during both fatigue and torque to failure testing (p > .05). Our specimen bone mineral density averages did not represent poor bone quality. The clinical implication of the present study is that distal fibular locking plates do not provide a mechanical advantage for trimalleolar ankle injuries in individuals with normal bone density and in the absence of fracture comminution.

  4. Clinical and radiological outcome after mini-open Latarjet technique with fixation of coracoid with Arthrex wedge mini-plate

    PubMed Central

    Chaudhary, Deepak; Goyal, Ankit; Joshi, Deepak; Jain, Vineet; Mohindra, Mukul; Mehta, Nitin

    2016-01-01

    Background Technical faults leading to coracoid fractures during screw insertion and coracoid graft osteolysis are concerns with standard screw fixation techniques in Latarjet procedure. The purpose of this study is to share our experience using Arthrex wedge profile plate with mini-open technique for graft fixation, that ensures better load distribution between coracoid graft and glenoid. Methods We did retrospective analysis of 24 patients with recurrent anterior shoulder instability after failed arthroscopic Bankart's repair. Arthroscopic examination of affected shoulder was done in lateral position before making patient supine for open Latarjet. A low profile wedge plate (Arthrex) with two screws was used for the procedure. CT analysis was performed post-operatively at 6 months to see graft union and results were evaluated using the Rowe and Walch Duplay score. Results Mean follow-up time was 26 months. Postoperatively, mean forward elevation was 170.6 + 4.6° (loss of average 5.9°) and mean external rotation was 42.5 + 5.3° (loss of average 3.1°). All patients returned to their previous occupation. None reported to be having any recurrent subluxation. Functional assessment done using Rowe score and Walch Duplay score showed statistically significant improvement (p value 0.034). There were no implant-related complications and no case of coracoid graft osteolysis. Conclusions Mini-open Latarjet with graft fixation with Arthrex mini-plate provides satisfactory outcome in patients who require reoperation due to dramatic bone loss and failed soft tissue reconstruction. The modified incision improves exposure enabling plate fixation and the secure fixation accelerates rehabilitation. PMID:26908972

  5. Simulated effect on the compressive and shear mechanical properties of bionic integrated honeycomb plates.

    PubMed

    He, Chenglin; Chen, Jinxiang; Wu, Zhishen; Xie, Juan; Zu, Qiao; Lu, Yun

    2015-05-01

    Honeycomb plates can be applied in many fields, including furniture manufacturing, mechanical engineering, civil engineering, transportation and aerospace. In the present study, we discuss the simulated effect on the mechanical properties of bionic integrated honeycomb plates by investigating the compressive and shear failure modes and the mechanical properties of trabeculae reinforced by long or short fibers. The results indicate that the simulated effect represents approximately 80% and 70% of the compressive and shear strengths, respectively. Compared with existing bionic samples, the mass-specific strength was significantly improved. Therefore, this integrated honeycomb technology remains the most effective method for the trial manufacturing of bionic integrated honeycomb plates. The simulated effect of the compressive rigidity is approximately 85%. The short-fiber trabeculae have an advantage over the long-fiber trabeculae in terms of shear rigidity, which provides new evidence for the application of integrated bionic honeycomb plates.

  6. Compressive failure modes and parameter optimization of the trabecular structure of biomimetic fully integrated honeycomb plates.

    PubMed

    Chen, Jinxiang; Tuo, Wanyong; Zhang, Xiaoming; He, Chenglin; Xie, Juan; Liu, Chang

    2016-12-01

    To develop lightweight biomimetic composite structures, the compressive failure and mechanical properties of fully integrated honeycomb plates were investigated experimentally and through the finite element method. The results indicated that: fracturing of the fully integrated honeycomb plates primarily occurred in the core layer, including the sealing edge structure. The morphological failures can be classified into two types, namely dislocations and compactions, and were caused primarily by the stress concentrations at the interfaces between the core layer and the upper and lower laminations and secondarily by the disordered short-fiber distribution in the material; although the fully integrated honeycomb plates manufactured in this experiment were imperfect, their mass-specific compressive strength was superior to that of similar biomimetic samples. Therefore, the proposed bio-inspired structure possesses good overall mechanical properties, and a range of parameters, such as the diameter of the transition arc, was defined for enhancing the design of fully integrated honeycomb plates and improving their compressive mechanical properties.

  7. Theoretical Determination of Lifetime of Compressed Plates at Elevated Temperatures

    NASA Technical Reports Server (NTRS)

    Herrmann, George; Chu, Hu-Nan

    1959-01-01

    A method for the theoretical determination of the lifetime of com- pressed plates at elevated temperatures is presented. In this approach, linearized equations are used throughout with the assumption that the plate material is a standard linear solid. The critical time (lifetime) is determined by reducing the time-dependent behavior to the time- independent response of purely elastic buckling. Theoretically predicted lifetimes of 2024-T3 (formerly 24S-T3) aluminum-alloy plates at 450 F are compared with experimental values obtained in previous work.

  8. Buckling and postbuckling behavior of square compression-loaded graphite-epoxy plates with circular cutouts

    NASA Technical Reports Server (NTRS)

    Nemeth, Michael P.

    1990-01-01

    An experimental study of the postbuckling behavior of square compression-loaded graphite-epoxy plates and isotropic plates with a central circular cutout is presented. Results are presented for unidirectional (0 sub 10)s and (90 sub 10)s plates, (0/90 sub 5)s plates, and for aluminum plates. Results are also presented for (+ or - O sub 6)s angle-ply plates for values of O = 30, 46, and 60 degrees. The experimental results indicate that the change in axial stiffness of a plate at buckling is strongly dependent upon cutout size and plate orthotropy. The presence of a cutout gives rise to an internal load distribution that changes, sometimes dramtically, as a function of cutout size coupled with the plate orthotropy. In the buckled state, the role of orthotropy becomes more significant since bending in addition to membrane orthotropy is present. Most of the plates with cutouts exhibited less postbuckling stiffness than the corresponding plate without a cutout, and the postbuckling stiffness decreased with increasing cutout size. However, some of the highly orthotropic plates with cutouts exhibited more postbuckling stiffness than the corresponding plate without a cutout.

  9. Buckling and postbuckling behavior of compression-loaded isotropic plates with cutouts

    NASA Technical Reports Server (NTRS)

    Nemeth, Michael P.

    1990-01-01

    An experimental study of the buckling and postbuckling behavior of square and rectangular compression loaded aluminum plates with centrally located circular, square, and elliptical cutouts is presented. Experimental results indicate that the plates exhibit overall trends of increasing buckling strain and decreasing initial postbuckling stiffness with increasing cutout width. Corresponding plates with circular and square cutouts of the same width buckle at approximately the same strain level, and exhibit approximately the same initial postbuckling stiffness. Results show that the reduction in initial postbuckling stiffness due to a cutout generally decreases as the plate aspect ratio increases. Other results presented indicate that square plates with elliptical cutouts having a large cutout-width-to-plate-width ratio generally lose prebuckling and initial postbuckling stiffness as the cutout height increases. However, the plates buckle at essentially the same strain level. Results also indicate that postbuckling stiffness is more sensitive to changes in elliptical cutout height than are prebuckling stiffness and buckling strain.

  10. Elastic and plastic buckling of simply supported solid-core sandwich plates in compression

    NASA Technical Reports Server (NTRS)

    Seide, Paul; Stowell, Elbridge Z

    1950-01-01

    A solution is presented for the problem of the compressive buckling of simply supported, flat, rectangular, solid-core sandwich plates stressed either in the elastic range or in the plastic range. Charts for the analysis of long sandwich plates are presented for plates having face materials of 24s-t3 aluminum alloy, 76s-t6 alclad aluminum alloy, and stainless steel. A comparison of computed and experimental buckling stresses of square solid-core sandwich plates indicates fair agreement between theory and experiment.

  11. Rate of Improvement following Volar Plate Open Reduction and Internal Fixation of Distal Radius Fractures

    PubMed Central

    Dillingham, Chris; Horodyski, MaryBeth; Struk, Aimee M.; Wright, Thomas

    2011-01-01

    Purpose. To determine recovery timeline of unstable distal radius fractures treated by open reduction and internal fixation with a locking volar plate. Methods. Data was collected prospectively on a consecutive series of twenty-seven patients during routine post-operative visits at 2 and 6 weeks, and 3, 6, 12 and 24 months. Range of motion measures and grip strength for both wrists were recorded. Results. Greatest gains were made within the first 3 months after surgery. Supination and pronation returned more quickly than flexion or extension, with supination and pronation both at 92% of the uninjured wrist at 3 months. Only flexion improved significantly between 3 and 6 months. All wrist motions showed some improvement until 1 year. Grip strength returned to 94% of the uninjured wrist by 12 months. Conclusions. Range of motion improvement will be greatest between 2 weeks and 3 months, with improvement continuing until 12 months. Grip strength should return to near normal by one year. Function and pain will improve, but not return to normal by the end of 12 months. Clinical Relevance. These results provide the surgeon with information that can be shared with patients on the anticipated timeline for normal recovery of function and strength. PMID:21991417

  12. The biomechanical effect of bone quality and fracture topography on locking plate fixation in periprosthetic femoral fractures.

    PubMed

    Leonidou, Andreas; Moazen, Mehran; Lepetsos, Panagiotis; Graham, Simon M; Macheras, George A; Tsiridis, Eleftherios

    2015-02-01

    Optimal management of periprosthetic femoral fractures (PFF) around a well fixed prosthesis (Vancouver B1) remains controversial as adequate fixation needs to be achieved without compromising the stability of the prosthesis. The aim of this study was to highlight the effect of bone quality i.e. canal thickness ratio (CTR), and fracture topography i.e. fracture angle and its position in relation to the stem, on the biomechanics of a locking plate for a Vancouver B1 fracture. A previously corroborated simplified finite element model of a femur with a cemented total hip replacement stem was used in this study. Canal thickness ratio (CTR) and fracture topography were altered in several models and the effect of these variations on the von Mises stress on the locking plate as well as the fracture displacement was studied. Increasing the CTR led to reduction of the von Mises stress on the locking plate as well as the fracture movement. In respect to the fracture angle with the medial cortex, it was shown that acute angles resulted in lower von Mises stress on the plate as opposed to obtuse angles. Furthermore, acute fracture angles resulted in lower fracture displacement compared to the other fractures considered here. Fractures around the tip of the stem had the same biomechanical effect on the locking plate. However, fractures more distal to the stem led to subsequent increase of stress, strain, and fracture displacement. Results highlight that in good bone quality and acute fracture angles, single locking plate fixation is perhaps an appropriate management method. On the contrary, for poor bone quality and obtuse fracture angles alternative management methods might be required as the fixation might be under higher risk of failure. Clinical studies for the management of PFF are required to further support our findings.

  13. Zygomatic complex fracture: A comparative evaluation of stability using titanium and bio-resorbable plates as one point fixation

    PubMed Central

    Tripathi, Nalini; Goyal, Manoj; Mishra, Brijesh; Dhasmana, Satish

    2013-01-01

    Background: The malar bone represents a strong bone on fragile support and its processes - frontal, orbital, maxillary and zygomatic are frequently the site of fracture. Current study was done to compare the stability of zygomatic complex fracture using Biodegradable plates and titanium miniplates with one point fixation. Materials and Methods: Twenty patients of zygomatic complex fracture were randomly selected and divided in two groups which were further divided into two subgroups (A, B). Group I patients were treated with titanium miniplate at zygomatic buttress and Group II was treated by bio-resorbable plates. One point fixation was done either at zygomatic buttress or at frontozygomatic suture and it was observed that both the site have been the most favored site of rigid internal fixation in terms of stability, aesthetics and prevention of rotation of the fracture segment in either vertical or horizontal axis. Conclusion: There is no significant difference in post operative outcomes between two groups, but still bioresorbable system has some advantage over titanium system as these plates resorbs over a period of time and does not cause any interference with growth and post operative radiotherapy. However application of biodegradable system demands highly précised technique. PMID:24665173

  14. Biomechanical analysis of expansion screws and cortical screws used for ventral plate fixation on the cervical spine

    PubMed Central

    Ullrich, Bernhard; Huber, Gerd; Morlock, Michael M.

    2009-01-01

    Compared to bicortical screws, the surgical risk of injuring intraspinal structures can be minimized with the use of monocortical screws. However, this reduction should not be achieved at the expense of the stability of the fixation. With monocortical stabilization, the expansion screws have the potential of absorbing high loads. Therefore, they are expected to be a suitable alternative to bicortical screws for revision surgeries and in osteoporotic bone. The purpose of this in vitro study was to investigate the stiffness of the two screw-plate systems used for ventral stabilization of the cervical spine, by focusing on the suitability of expansion screws as tools for revision treatments. The study was conducted in ten functional units of human cervical spines. The device sample stiffness was determined for four conditions using a turning moment of 2.25 N m each around one of the three principle axes. The conditions were native, destabilized, primarily stabilized with one of the screw-plate systems, followed by secondary stabilization using the expansion screw implant. The stabilized samples achieved a comparable, in most cases higher stiffness than the native samples. The samples undergoing secondary stabilization using expansion screws tend to display greater stiffness for all three axes compared to the primarily stabilized samples. The achieved tightening moment of the screws was higher than the one achieved with primary fixation. Both plates revealed similar primary stability. Revision surgeries with secondary instrumentation achieve a high stiffness of the screwed up segments. Monocortical expansion screws combined with a trapezoidal plate allow ventral stabilization of the cervical spine that is comparable to the plate fixation using bicortical screws. PMID:19588171

  15. Stability and Process of Destruction of Compressed Plate of Layered Composite Materials With Defects

    NASA Astrophysics Data System (ADS)

    Bokhoeva, L. A.; Rogov, V. E.; Chermoshentseva, A. S.; Lobanov, D. V.

    2016-08-01

    Interlayer defects in composite materials are a pressing problem, which affecting their performance characteristics. In this research, we considered the problem of the stability and of the fracture process of the compressed thin plate made of laminated composite materials with the interlayer defects. In this research we had got a critical equation for a plate with interlayer defect. The experiment showed the effect and the quantity of nano-dispersed additives on the mechanical properties of composite materials with interlayer defects.

  16. FIXATION OF SUPRACONDYLAR FEMORAL FRACTURES: A BIOMECHANICAL ANALYSIS COMPARING 95° BLADE PLATES AND DYNAMIC CONDYLAR SCREWS (DCS)

    PubMed Central

    Percope Andrade, Marco Antônio; Rodrigues, André Soares; Mendonça, Celso Junio; Santos Portela, Luiz Gustavo

    2015-01-01

    Objective: To determine, by means of comparative biomechanical tests, whether greater compressive load resistance and flexion is presented by 95° angled blade plates or by dynamic condylar screws (DCS), and to correlate the failure type presented during the tests with each type of plate. Methods: Sixty-five porcine femurs were subjected to 1 cm medial wedge osteotomy, in the metaphysis, to simulate an unstable supracondylar femoral fracture. Osteosynthesis was performed on these pieces: 35 were fixed using 95° lateral blade plates and 30 with DCS plates. Another variable studied was the failure type presented in each group, in an attempt to correlate this with the type of plate. Results: There were no statistically significant differences in biomechanical resistance between the two types of plates, or between the failure type and the plate type used for the osteosynthesis. Conclusion: The two types of plate behaved in a similar fashion. However, the angled blade plate proved to be superior to the DCS in the flexion test. No statistical difference in failure type or type of plate used was observed. PMID:27022525

  17. TIBIOTARSAL COMPRESSION ARTHRODESIS USING A LATERAL LOCKING PLATE.

    PubMed

    Coughlin, Michael J; Nery, Caio; Baumfeld, Daniel; Jastifer, James

    2012-01-01

    Objetivos: A artrodese tibiotársica (TT) continua sendo uma importante opção no tratamento da artrose primária ou pós-traumática do tornozelo mas persiste ainda a controvérsia sobre o melhor método de fixação do foco de artrodese. Independentemente do tipo de material utilizado, o objetivo maior é a obtenção da fusão articular sólida, saudável e indolor. O propósito do presente estudo é apresentar os resultados preliminares de um novo sistema de placa bloqueada lateral compressiva para a artrodese do tornozelo. Método: Treze pacientes consecutivos portadores de artrose tibiotársica foram submetidos à artrodese do tornozelo nove pacientes eram homens e quatro mulheres. Com o auxílio de um guia, as superfícies articulares do talo e da tíbia foram decorticadas. Um sistema de compressão foi aplicado para evitar o alinhamento indesejável dos segmentos e uma placa bloqueada pré-moldada lateral foi utilizada para obter a fusão articular. Resultados: Tanto o escore AOFAS quanto o VAS melhoraram com a cirurgia. Todos os tornozelos operados consolidaram dentro do prazo de seis meses. Em todos os pacientes, foi obtido um ótimo alinhamento nos planos sagital, coronal e transverso. Conclusão: Acreditamos que a combinação de compressão bilateral, cortes ósseos com contornos pré-demarcados e placa lateral bloqueada, constitui uma técnica moderna, segura e útil para a artrodese do tornozelo.

  18. Column and Plate Compressive Strength of Extruded XB75S-T Aluminum Alloy

    NASA Technical Reports Server (NTRS)

    Heimerl, George J.; Roy, J. Albert

    1944-01-01

    Results are presented of tests to determine the column and plate compressive strength of extruded XB75S-T aluminum alloy, and comparative values are shown for 24S-T aluminum-alloy sheet. Stress-strain curves are also given,

  19. Damage Progression in Buckle-Resistant Notched Composite Plates Loaded in Uniaxial Compression

    NASA Technical Reports Server (NTRS)

    McGowan, David M.; Davila, Carlos G.; Ambur, Damodar R.

    2001-01-01

    Results of an experimental and analytical evaluation of damage progression in three stitched composite plates containing an angled central notch and subjected to compression loading are presented. Parametric studies were conducted systematically to identify the relative effects of the material strength parameters on damage initiation and growth. Comparisons with experiments were conducted to determine the appropriate in situ values of strengths for progressive failure analysis. These parametric studies indicated that the in situ value of the fiber buckling strength is the most important parameter in the prediction of damage initiation and growth in these notched composite plates. Analyses of the damage progression in the notched, compression-loaded plates were conducted using in situ material strengths. Comparisons of results obtained from these analyses with experimental results for displacements and axial strains show good agreement.

  20. Evaluation of a new approach for modelling the screw-bone interface in a locking plate fixation: a corroboration study.

    PubMed

    Moazen, Mehran; Mak, Jonathan H; Jones, Alison C; Jin, Zhongmin; Wilcox, Ruth K; Tsiridis, Eleftherios

    2013-07-01

    Computational modelling of the screw-bone interface in fracture fixation constructs is challenging. While incorporating screw threads would be a more realistic representation of the physics, this approach can be computationally expensive. Several studies have instead suppressed the threads and modelled the screw shaft with fixed conditions assumed at the screw-bone interface. This study assessed the sensitivity of the computational results to modelling approaches at the screw-bone interface. A new approach for modelling this interface was proposed, and it was tested on two locking screw designs in a diaphyseal bridge plating configuration. Computational models of locked plating and far cortical locking constructs were generated and compared to in vitro models described in prior literature to corroborate the outcomes. The new approach led to closer agreement between the computational and the experimental stiffness data, while the fixed approach led to overestimation of the stiffness predictions. Using the new approach, the pattern of load distribution and the magnitude of the axial forces, experienced by each screw, were compared between the locked plating and far cortical locking constructs. The computational models suggested that under more severe loading conditions, far cortical locking screws might be under higher risk of screw pull-out than the locking screws. The proposed approach for modelling the screw-bone interface can be applied to any fixation involved application of screws.

  1. Comparison of postoperative changes in the distal and proximal segments between conventional and sliding mini-plate fixation following mandibular setback

    PubMed Central

    Kim, Seong-Sik; Kwak, Kyoung-Ho; Ko, Ching-Chang; Park, Soo-Byung; Son, Woo-Sung

    2016-01-01

    Objective The purpose of the present study was to evaluate the postoperative three-dimensional (3D) changes in the proximal segments after mandibular setback sagittal split ramus osteotomy and to compare the changes between the conventional mini-plate fixation and semi-rigid sliding plate fixation. Methods Cone-beam computed tomography (CBCT) images were used to evaluate the postoperative 3D changes in the proximal segments during the healing process. CBCT images were superimposed using the symphysis and the lower anterior mandible as references. Results There were no statistically significant differences between the conventional mini-plate and semi-rigid sliding plate groups (p > 0.05). With respect to the distribution of changes greater than 2 mm in the landmarks, the right condylion, right coronoid process, and left condylion showed ratios of 55.6%, 50.0%, and 44.4%, respectively, in the semi-rigid sliding plate group; however, none of the landmarks showed ratios greater than 30% in the conventional mini-plate group. Conclusions There were no statistically significant differences in postoperative changes in the segments between the conventional mini-plate and semi-rigid sliding plate groups. Nevertheless, while selecting the type of fixation technique, clinicians should consider that landmarks with greater than 2 mm changes were higher in the semi-rigid sliding plate group than in the conventional mini-plate group. PMID:27896211

  2. A biomechanical comparison of proximal femoral nails and locking proximal anatomic femoral plates in femoral fracture fixation

    PubMed Central

    Ozkan, Korhan; Türkmen, İsmail; Sahin, Adem; Yildiz, Yavuz; Erturk, Selim; Soylemez, Mehmet Salih

    2015-01-01

    Background: The incidence of fractures in the trochanteric area has risen with the increasing numbers of elderly people with osteoporosis. Although dynamic hip screw fixation is the gold standard for the treatment of stable intertrochanteric femur fractures, treatment of unstable intertrochanteric femur fractures still remains controversial. Intramedullary devices such as Gamma nail or proximal femoral nail and proximal anatomic femur plates are in use for the treatment of intertrochanteric femur fractures. There are still many investigations to find the optimal implant to treat these fractures with minimum complications. For this reason, we aimed to perform a biomechanical comparison of the proximal femoral nail and the locking proximal anatomic femoral plate in the treatment of unstable intertrochanteric fractures. Materials and Methods: Twenty synthetic, third generation human femur models, obtained for this purpose, were divided into two groups of 10 bones each. Femurs were provided as a standard representation of AO/Orthopedic Trauma Associationtype 31-A2 unstable fractures. Two types of implantations were inserted: the proximal femoral intramedullary nail in the first group and the locking anatomic femoral plate in the second group. Axial load was applied to the fracture models through the femoral head using a material testing machine, and the biomechanical properties of the implant types were compared. Result: Nail and plate models were locked distally at the same level. Axial steady load with a 5 mm/m velocity was applied through the mechanical axis of femur bone models. Axial loading in the proximal femoral intramedullary nail group was 1.78-fold greater compared to the plate group. All bones that had the plate applied were fractured in the portion containing the distal locking screw. Conclusion: The proximal femoral intramedullary nail provides more stability and allows for earlier weight bearing than the locking plate when used for the treatment of

  3. The use of mini plates for intermaxillary fixation in a severely comminuted mandibular fracture with bilateral condylar fractures

    PubMed Central

    Clohessy, James William; Chang, Frank; Subramaniam, Shiva S.

    2016-01-01

    Intermaxillary fixation (IMF) is an integral technique utilized by maxillofacial surgeons to appropriately reduce and relate maxillary and mandibular fractures to both one another and the facial skeleton. This case report reviews the management of a comminuted mandibular fracture including inoperable bilateral condylar fractures that precluded the use of convention IMF techniques necessitating an alternative technique. This was achieved in the form of modified bony plates extending intraorally. Postoperative review showed favorable results with occlusion and range of motion comparable to the premorbid function and no unforeseen complications.

  4. Clinical results of using the proximal humeral internal locking system plate for internal fixation of displaced proximal humeral fractures.

    PubMed

    Norouzi, Masoud; Naderi, Mohammad Nasir; Komasi, Mehdi Hemmati; Sharifzadeh, Seyyed Reza; Shahrezaei, Mostafa; Eajazi, Alireza

    2012-05-01

    Proximal humerus fractures are accounting for 4-5% of all fractures with increasing incidence. Proximal Humeral Internal Locking System (PHILOS) plate is a new plate which permits early mobility and lowers the risk of complications. The aim of this study was to evaluate the functional outcome and the complication rate after using this plate. Between 2006-2008, 37 patients with displaced 2-, 3-, and 4-part fractures of the proximal humerus underwent surgery using PHILOS plate. The mean range of follow-up was 12 months. Twenty patients were aged 60 years and younger, and 17 were aged older than 60 years. The average American Shoulder and Elbow Surgeons (ASES) score at the final follow-up was 77.62. According to Michener and colleagues classification, 5.4% of patients had an excellent outcome, 72.9% were minimally functionally limited, 16.2% were moderately functionally limited, and 5.4% were maximally functionally limited. The average ASES score between patients 60 years and older and those 60 years and younger was not different significantly. One patient developed avascular necrosis of the humeral head, 2 patients developed an infection, and no patients developed a nonunion. Fixation with PHILOS plate can be considered a good method with high union rates for this kind of fracture, especially in the older population with osteoporotic bone.

  5. In situ deformation of growth plate chondrocytes in stress-controlled static vs dynamic compression.

    PubMed

    Zimmermann, Elizabeth A; Bouguerra, Séréna; Londoño, Irene; Moldovan, Florina; Aubin, Carl-Éric; Villemure, Isabelle

    2017-03-11

    Longitudinal bone growth in children/adolescents occurs through endochondral ossification at growth plates and is influenced by mechanical loading, where increased compression decreases growth (i.e., Hueter-Volkmann Law). Past in vivo studies on static vs dynamic compression of growth plates indicate that factors modulating growth rate might lie at the cellular level. Here, in situ viscoelastic deformation of hypertrophic chondrocytes in growth plate explants undergoing stress-controlled static vs dynamic loading conditions was investigated. Growth plate explants from the proximal tibia of pre-pubertal rats were subjected to static vs dynamic stress-controlled mechanical tests. Stained hypertrophic chondrocytes were tracked before and after mechanical testing with a confocal microscope to derive volumetric, axial and lateral cellular strains. Axial strain in hypertrophic chondrocytes was similar for all groups, supporting the mean applied compressive stress's correlation with bone growth rate and hypertrophic chondrocyte height in past studies. However, static conditions resulted in significantly higher lateral (p<0.001) and volumetric cellular strains (p≤0.015) than dynamic conditions, presumably due to the growth plate's viscoelastic nature. Sustained compression in stress-controlled static loading results in continued time-dependent cellular deformation; conversely, dynamic groups have less volumetric strain because the cyclically varying stress limits time-dependent deformation. Furthermore, high frequency dynamic tests showed significantly lower volumetric strain (p=0.002) than low frequency conditions. Mechanical loading protocols could be translated into treatments to correct or halt progression of bone deformities in children/adolescents. Mimicking physiological stress-controlled dynamic conditions may have beneficial effects at the cellular level as dynamic tests are associated with limited lateral and volumetric cellular deformation.

  6. Intramedullary Nailing Versus Plate Fixation for the Treatment Displaced Midshaft Clavicular Fractures: A Systematic Review and Meta-Analysis

    PubMed Central

    Hussain, Nasir; Sermer, Corey; Prusick, Parker J.; Banfield, Laura; Atrey, Amit; Bhandari, Mohit

    2016-01-01

    The two commonly performed surgical techniques used to repair displaced midshaft clavicle fractures are plate fixation or intramedullary nailing; however, despite recent evidence, the optimal method to treat such fractures remains a continued topic of debate. A meta-analysis of randomized controlled trials (RCTs) was conducted to evaluate long term function, complications, and operative duration in adult patients receiving intramedullary nailing in comparison to plating. Seven RCTs and three quasi-randomized trials were included. No significant difference was found in long-term function between the two groups (MD: −0.66, 95% CI: −2.03 to 0.71, I2 = 62%, p = 0.34). Patients who received plating had a 2.19 times increased risk of treatment failure, but this failed to reach significance (95% CI: 0.93 to 5.15, I2 = 0%, p = 0.07). The risk of non-operative complications was 2.11 times higher in patients who received plating and this reached statistical significance (95% CI: 1.38 to 3.23, I2 = 53%, p = 0.0006). Finally, plating significantly prolonged operative duration by 20.16 minutes (95% CI: 16.87 to 23.44, I2 = 56%, p < 0.00001). Our results suggest that intramedullary nailing and plating provide equivalent long-term functional outcomes; however, plating may lead to a higher risk of treatment failure and non-operative complications. PMID:27762393

  7. Behavior of a plate strip under shear and compressive stresses beyond the buckling limit

    NASA Technical Reports Server (NTRS)

    Kromm, A; Marguerre, K

    1938-01-01

    The present report is an extension of previous theoretical investigations on the elastic behavior of a plate under compression and shear in the region above the critical. The main object is the clarification of the behavior immediately above the buckling limit since no theoretical expressions for this range have thus far been found and since experimentally, too, any degree of regularity in the behavior of the plate in the range between the critical load and about three to four times the critical, is discernible only with difficulty.

  8. Investigation of the Compressive Strength and Creep Lifetime of 2024-T3 Aluminum-Alloy Plates at Elevated Temperatures

    NASA Technical Reports Server (NTRS)

    Mathauser, Eldon E; Deveikis, William D

    1957-01-01

    The results of elevated-temperature compressive strength and creep tests of 2024-t3 (formerly 24s-t3) aluminum alloy plates supported in v-grooves are presented. The strength-test results indicate that a relation previously developed for predicting plate compressive strength for plates of all materials at room temperature is also satisfactory for determining elevated-temperature strength. Creep-lifetime results are presented for plates in the form of master creep-lifetime curves by using a time-temperature parameter that is convenient for summarizing tensile creep-rupture data. A comparison is made between tensile and compressive creep lifetime for the plates and a method that made use of isochronous stress-strain curves for predicting plate-creep failure stresses is investigated.

  9. A biomechanical comparison of external skeletal fixation and plating for the stabilization of ilial osteotomies in dogs.

    PubMed

    Fitzpatrick, N; Lewis, D; Cross, A

    2008-01-01

    This in vitro study compares the biomechanical properties of two methods of ilial fracture repair in dogs. Ten pelves were harvested from skeletally mature mixed breed dogs weighing 20-27 kg and bilateral oblique ilial body osteotomies were created. One hemipelvis from each dog was stabilized with a 2.7 mm plate and screws and the contralateral hemipelvis was stabilized with a five pin linear external fixator construct. Each hemipelvis was mounted at an angle of 30 degrees to an actuator platform, such that the acetabulum was centrally loaded by a steel sphere attached to the load cell of a servohydraulic materials testing machine. The construct was loaded at a constant rate of 20 mm/min. A load/displacement curve was generated for each hemipelvis by plotting the sustained load against the actuator movement. The stiffness, yield load and failure load for each hemipelvis were determined from the load/displacement curve. Bending stiffness was defined as the slope of the load/displacement curve from 100 N to yield load. The mode of failure was determined by observations made during testing and gross inspection of each specimen. The mean construct stiffness, yield load and failure load were compared between stabilization groups using a Student's paired t-test with statistical significance set at p<0.05. Nine out of 10 of the hemipelves that were stabilized by plates and screws failed catastrophically by fracture through the caudal screw holes and nine out of 10 of the hemipelves that were stabilized using an external fixator failed by fracture of the ischium in the region supported by the mounting roller, propagating through the most caudal ischial pin. There was not any significant difference (P=0.22) in bending stiffness between stabilization techniques, but yield (1467 N vs 2620 N; P=0.04) and failure (1918 N vs 2687 N; P=0.002) loads were significantly greater for hemipelves stabilized with external fixators.

  10. A Novel Shape Memory Plate Osteosynthesis for Noninvasive Modulation of Fixation Stiffness in a Rabbit Tibia Osteotomy Model

    PubMed Central

    Müller, Christian W.; Pfeifer, Ronny; Meier, Karen; Decker, Sebastian; Reifenrath, Janin; Gösling, Thomas; Wesling, Volker; Krettek, Christian; Hurschler, Christof; Krämer, Manuel

    2015-01-01

    Nickel-titanium shape memory alloy (NiTi-SMA) implants might allow modulating fracture healing, changing their stiffness through alteration of both elastic modulus and cross-sectional shape by employing the shape memory effect (SME). Hypotheses: a novel NiTi-SMA plate stabilizes tibia osteotomies in rabbits. After noninvasive electromagnetic induction heating the alloy exhibits the SME and the plate changes towards higher stiffness (inverse dynamization) resulting in increased fixation stiffness and equal or better bony healing. In 14 rabbits, 1.0 mm tibia osteotomies were fixed with our experimental plate. Animals were randomised for control or induction heating at three weeks postoperatively. Repetitive X-ray imaging and in vivo measurements of bending stiffness were performed. After sacrifice at 8 weeks, macroscopic evaluation, µCT, and post mortem bending tests of the tibiae were carried out. One death and one early implant dislocation occurred. Following electromagnetic induction heating, radiographic and macroscopic changes of the implant proved successful SME activation. All osteotomies healed. In the treatment group, bending stiffness increased over time. Differences between groups were not significant. In conclusion, we demonstrated successful healing of rabbit tibia osteotomies using our novel NiTi-SMA plate. We demonstrated shape-changing SME in-vivo through transcutaneous electromagnetic induction heating. Thus, future orthopaedic implants could be modified without additional surgery. PMID:26167493

  11. UK Fixation of Distal Tibia Fractures (UK FixDT): protocol for a randomised controlled trial of ‘locking’ plate fixation versus intramedullary nail fixation in the treatment of adult patients with a displaced fracture of the distal tibia

    PubMed Central

    Achten, Juul; Parsons, Nicholas R; McGuinness, Katie R; Petrou, Stavros; Lamb, Sarah E; Costa, Matthew L

    2015-01-01

    Introduction The treatment of displaced, extra-articular fractures of the distal tibia remains controversial. These injuries are difficult to manage due to limited soft tissue cover, poor vascularity of the area and proximity to the ankle joint. Surgical treatment options are expanding and include locked intramedullary nails, plate and screw fixation and external fixator systems. The nail and plate options are most commonly used in the UK, but controversy exists over which treatment is most clinically and cost-effective. In this multicentre randomised controlled trial we aim to assess ratings of disability 6 months postinjury in patients who have sustained a distal tibia fracture treated with either an intramedullary nail or plate and locking screw fixation. Methods and analysis Adult patients presenting at trial centres with an acute fracture of the distal tibia will be considered for inclusion. A total of 320 patients will provide 90% power to detect a difference of 8 points in Disability Rating Index (DRI) score at 6 months at the 5% level. The randomisation sequence is stratified by trial centre and age, and administered via web-based service with 1:1 treatment allocation. Baseline demographic and pre-injury functional data and radiographs will be collected using the DRI, Olerud and Molander, and EuroQol EQ-5D questionnaire. Clinical assessment, early complications and radiographs will be recorded at 6–8 weeks. Functional outcome, health-related quality of life and resource use will be collected at 3, 6 and 12 months postoperatively. The main analysis will investigate differences in DRI 6 months postsurgery, between the two treatment groups, on an intention-to-treat basis. Tests will be two-sided and considered to provide evidence for a significant difference if p values are <0.05. Ethics and dissemination NRES Committee West-Midlands, 6/11/2012 (ref:12/WM/0340). The results of the trial will be disseminated via peer-reviewed publications and

  12. A Biomechanical Comparison of Three 1.5-mm Plate and Screw Configurations and a Single 2.0-mm Plate for Internal Fixation of a Mandibular Condylar Fracture

    PubMed Central

    Aquilina, Peter; Parr, William C.H.; Chamoli, Uphar; Wroe, Stephen; Clausen, Philip

    2014-01-01

    The most stable pattern of internal fixation for mandibular condyle fractures is an area of ongoing discussion. This study investigates the stability of three patterns of plate fixation using readily available, commercially pure titanium implants. Finite element models of a simulated mandibular condyle fracture were constructed. The completed models were heterogeneous in bone material properties, contained approximately 1.2 million elements and incorporated simulated jaw adducting musculature. Models were run assuming linear elasticity and isotropic material properties for bone. No human subjects were involved in this investigation. The stability of the simulated condylar fracture reduced with the different implant configurations, and the von Mises stresses of a 1.5-mm X-shaped plate, a 1.5-mm rectangular plate, and a 1.5-mm square plate (all Synthes (Synthes GmbH, Zuchwil, Switzerland) were compared. The 1.5-mm X plate was the most stable of the three 1.5-mm profile plate configurations examined and had comparable mechanical performance to a single 2.0-mm straight four-hole plate. This study does not support the use of rectangular or square plate patterns in the open reduction and internal fixation of mandibular condyle fractures. It does provide some support for the use of a 1.5-mm X plate to reduce condylar fractures in selected clinical cases. PMID:25136411

  13. Measurements of displacement around holes in composite plates subjected to quasi-static compression

    NASA Technical Reports Server (NTRS)

    Duke, J. C., Jr.; Post, D.; Czarnek, R.; Asundi, A.

    1982-01-01

    Attempts to develop a whole-field, high sensitivity optical technque for measurement of load induced changes of thickness of composite plates are described. Graphite-epoxy plates of quasi-isotropic layup were used as test specimens. Changes of thickness of three plates, each with a central hole of different size, were measured as a function of applied compressive loads. The first test specimen showed localized zones where no holographic fringes were present, surrounded by zones of low fringe contrast. This was thought to be a result of localized motion or creep. Subsequent tests with an increased time interval between specimen loading and holographic exposure demonstrated no localized zones of absent fringes. No plausible explanation for radical differences in the quality of fringe patterns was found, although the use of specimens having a high quality mirrorized surface provided superior change of thickness patterns. Recommendations for further investigations and changes in test procedure are presented.

  14. Treatment of Non Unions of Subtrochanteric Fractures Using an Anatomical Proximal Femur Locked Compression Plate – A Prospective Study of 13 Patients

    PubMed Central

    Balasubramanian, Navin; Babu, Ganesh; Prakasam, Sindhuja

    2016-01-01

    Introduction: Subtrochanteric fractures have a bimodal age distribution. They are mostly due to high violence trauma in the younger age group. They almost always require open reduction and internal fixation. Due to the increase in the emergence of native bone setters, these fractures are increasingly been managed by these spurious bone setters using native splints. As a result, non-union rate is high among such patients. These patients definitely need open reduction with internal fixation +/- bone grafting. The choice of implants used can be either a dynamic condylar screw plate (DCS) orproximal femoral nail (PFN). Case series: Here we have used a surgical grade 316 L stainless steel proximal femoral anatomical locked compression plate (PF-LCP). We analyzed 13 patients with established non unions of subtrochanteric fractures treated in our centre by the use of the PF-LCP. There were 10 males and 3 females. The average age was 48.23 years. All our patients were followed up by serial radiographs at 6, 12, 18, 24 weeks and thereafter at 6 months interval. Union was achieved in 11 out of 13 patients at 12 weeks whereas two patients had delayed union which eventually healed at 18 weeks and 24 weeks. The average Harris hip score at 1 year follow-up was excellent in eight, good in four and fair in one patient respectively. Conclusion: We conclude that in complicated non-unions, the use of PF-LCP has a definite positive role in the management of such cases. PMID:27299132

  15. In Vivo Syndesmotic Over-Compression After Fixation of Ankle Fractures with a Syndesmotic Injury

    PubMed Central

    Cherney, Steven M.; Haynes, Jacob A.; Spraggs-Hughes, Amanda; McAndrew, Christopher M.; Ricci, William M.; Gardner, Michael J.

    2015-01-01

    Objectives The goals of this study were to assess syndesmotic reductions utilizing computerized tomography (CT) scans, and to determine if malreductions were associated with certain injury types or reduction forceps. Design Prospective cohort Setting Urban Level 1 Trauma center Patients Twenty-seven patients with operatively treated syndesmotic injuries were recruited prospectively. Intervention Patients underwent postoperative bilateral CT scans of the ankle and hindfoot to assess syndesmotic reduction. The uninjured extremity was used as a control. Main outcome measurement Side-to-side differences of fibula position within the tibial incisura were measured at several anatomic points and analyzed based on injury type, the presence of posterior malleolar injury, level of fracture, and type of reduction forceps used. Results On average, operatively treated syndesmotic injuries were over-compressed (fibular medialization) by 1mm (p < .001) and externally rotated by 5° (p = .002) when compared to the uninjured extremity. The absence of a posterior malleolar injury and Weber B (OTA 44-B) fractures seemed to have a protective effect against malrotation, but not against over-compression. There was no difference in malreduction based on type of clamp used. Conclusions It is possible, and highly likely based on these data, to over-compress the syndesmosis when using a reduction forceps. Care should be taken to avoid over-compression, as this may affect ankle motion and functional outcome. This is the first in vivo series of syndesmotic over-compression to our knowledge. PMID:26295735

  16. Biomechanical Evaluation of Interfragmentary Compression At Tibia Plateau Fractures In Vitro Using Different Fixation Techniques: A CONSORT-Compliant Article: Erratum.

    PubMed

    2015-02-01

    [In the article "Biomechanical Evaluation of Interfragmentary Compression At Tibia Plateau Fractures In Vitro Using Different Fixation Techniques: A CONSORT-compliant" article, which appeared in Volume 94, Issue 1 of Medicine, a line denoting dual authorship was omitted. K. Kojima and B. Gueorguiev contributed equally to the article.].

  17. Immuno-inflammatory tissue reaction to stainless-steel and titanium plates used for internal fixation of long bones.

    PubMed

    Voggenreiter, Gregor; Leiting, Stefan; Brauer, Holger; Leiting, Peter; Majetschak, Matthias; Bardenheuer, Mark; Obertacke, Udo

    2003-01-01

    The immuno-inflammatory responses to stainless-steel (21 implants in 20 patients) and titanium plates (22 implants in 20 patients) used in the treatment of long bone fractures were studied immunohistochemically. All fractures healed without complications. In the soft tissue adjacent to the surface of the implants a dark discolouration of the tissue was visible in 18/21 stainless-steel and 20/22 titanium plates. Tissue specimens of all patients contained positive staining for macrophages (CD68-positive cells). Serial sections showed that the majority of cells were found to express the HLA-DR molecule indicating their activation. Many of the macrophages were surrounded by clusters of T-lymphocytes (CD3-positive cells). 17 out of 21 steel specimens and 15 out of 22 titanium specimens showed the infiltration of moderate amounts of cytotoxic T-lymphocytes (CD8-positive cells). Moderate amounts of B-lymphocytes (CD79alpha positive cells) were evident in four patients with steel and six patients with titanium implants. The results of the present study clearly demonstrate the presence of a marked inflammation and tissue reaction in the soft tissue covering stainless-steel and titanium plates used for internal fixation of fractures of long bones independently from the material used.

  18. Intramedullary plate fixation of a distal humerus fracture: a case report.

    PubMed

    Russell, George V; Pearsall, Albert W

    2002-05-01

    A case of a complex distal humeral fracture is presented. The patient lacked sufficient bony architecture to allow for conventional reconstruction. A technique is described using an intramedullary plate to obtain bony stabilization and permit early range of motion exercises.

  19. Evaluation of poly(lactic-co-glycolic acid) plate and screw system for bone fixation.

    PubMed

    Park, Subin; Kim, Jin Hee; Kim, Il Hwan; Lee, Minsu; Heo, Suhak; Kim, Hong; Kim, Eun Hee; Choy, Young Bin; Heo, Chan Yeong

    2013-05-01

    In this study, we investigated the efficacy and safety of the recently developed modifiable bioabsorbable plates and screws, which are made of PLGA [poly(lactic-co-glycolic acids)]. An in vitro extract test and a mammalian erythrocyte micronucleus test revealed that neither cytotoxicity nor genotoxicity was observed with the plates and screws tested in this study. An in vivo mandible fracture model in rabbit was introduced to evaluate the in vivo efficacy and of the PLGA-based plates and screws. At 4, 6, 8, and 10 weeks after implantation, tissue specimens were taken from the implanted sites of the rabbits and a histologic analysis was performed for each of the specimens. After 4 weeks, the plate was covered by connective tissues and severe chronic active inflammation in soft tissue was observed. After 6 weeks, the inflammation decreased and some of the specimens exhibited new bone formation around the periosteum. After 8 and 10 weeks, new bone formation was observed with all samples, where almost no severe inflammation was involved, implying the healing of the fracture. Given these, it can be suggested that the biodegradable plate and screw system that we evaluated in this study is effective for treatment of mandible fracture, one of the regions under a high load-bearing condition. The adjustment process and the long-term follow-up study are in progress for clinical application of the plate and screw system introduced in this study.

  20. Surgical Fixation of Sternal Fractures: Preoperative Planning and a Safe Surgical Technique Using Locked Titanium Plates and Depth Limited Drilling

    PubMed Central

    Schulz-Drost, Stefan; Oppel, Pascal; Grupp, Sina; Schmitt, Sonja; Carbon, Roman Th.; Mauerer, Andreas; Hennig, Friedrich F.; Buder, Thomas

    2015-01-01

    Different ways to stabilize a sternal fracture are described in literature. Respecting different mechanisms of trauma such as the direct impact to the anterior chest wall or the flexion-compression injury of the trunk, there is a need to retain each sternal fragment in the correct position while neutralizing shearing forces to the sternum. Anterior sternal plating provides the best stability and is therefore increasingly used in most cases. However, many surgeons are reluctant to perform sternal osteosynthesis due to possible complications such as difficulties in preoperative planning, severe injuries to mediastinal organs, or failure of the performed method. This manuscript describes one possible safe way to stabilize different types of sternal fractures in a step by step guidance for anterior sternal plating using low profile locking titanium plates. Before surgical treatment, a detailed survey of the patient and a three dimensional reconstructed computed tomography is taken out to get detailed information of the fracture’s morphology. The surgical approach is usually a midline incision. Its position can be described by measuring the distance from upper sternal edge to the fracture and its length can be approximated by the summation of 60 mm for the basis incision, the thickness of presternal soft tissue and the greatest distance between the fragments in case of multiple fractures. Performing subperiosteal dissection along the sternum while reducing the fracture, using depth limited drilling, and fixing the plates prevents injuries to mediastinal organs and vessels. Transverse fractures and oblique fractures at the corpus sterni are plated longitudinally, whereas oblique fractures of manubrium, sternocostal separation and any longitudinally fracture needs to be stabilized by a transverse plate from rib to sternum to rib. Usually the high convenience of a patient is seen during follow up as well as a precise reconstruction of the sternal morphology. PMID

  1. Surgical fixation of sternal fractures: preoperative planning and a safe surgical technique using locked titanium plates and depth limited drilling.

    PubMed

    Schulz-Drost, Stefan; Oppel, Pascal; Grupp, Sina; Schmitt, Sonja; Carbon, Roman Th; Mauerer, Andreas; Hennig, Friedrich F; Buder, Thomas

    2015-01-05

    Different ways to stabilize a sternal fracture are described in literature. Respecting different mechanisms of trauma such as the direct impact to the anterior chest wall or the flexion-compression injury of the trunk, there is a need to retain each sternal fragment in the correct position while neutralizing shearing forces to the sternum. Anterior sternal plating provides the best stability and is therefore increasingly used in most cases. However, many surgeons are reluctant to perform sternal osteosynthesis due to possible complications such as difficulties in preoperative planning, severe injuries to mediastinal organs, or failure of the performed method. This manuscript describes one possible safe way to stabilize different types of sternal fractures in a step by step guidance for anterior sternal plating using low profile locking titanium plates. Before surgical treatment, a detailed survey of the patient and a three dimensional reconstructed computed tomography is taken out to get detailed information of the fracture's morphology. The surgical approach is usually a midline incision. Its position can be described by measuring the distance from upper sternal edge to the fracture and its length can be approximated by the summation of 60 mm for the basis incision, the thickness of presternal soft tissue and the greatest distance between the fragments in case of multiple fractures. Performing subperiosteal dissection along the sternum while reducing the fracture, using depth limited drilling, and fixing the plates prevents injuries to mediastinal organs and vessels. Transverse fractures and oblique fractures at the corpus sterni are plated longitudinally, whereas oblique fractures of manubrium, sternocostal separation and any longitudinally fracture needs to be stabilized by a transverse plate from rib to sternum to rib. Usually the high convenience of a patient is seen during follow up as well as a precise reconstruction of the sternal morphology.

  2. Anterior cervical fusion with interbody cage containing beta-tricalcium phosphate augmented with plate fixation: a prospective randomized study with 2-year follow-up.

    PubMed

    Dai, Li-Yang; Jiang, Lei-Sheng

    2008-05-01

    A variety of bone graft substitutes, interbody cages, and anterior plates have been used in cervical interbody fusion, but no controlled study was conducted on the clinical performance of beta-tricalcium phosphate (beta-TCP) and the effect of supplemented anterior plate fixation. The objective of this prospective, randomized clinical study was to evaluate the effectiveness of implanting interbody fusion cage containing beta-TCP for the treatment of cervical radiculopathy and/or myelopathy, and the fusion rates and outcomes in patients with or without randomly assigned plate fixation. Sixty-two patients with cervical radiculopathy and/or myelopathy due to soft disc herniation or spondylosis were treated with one- or two-level discectomy and fusion with interbody cages containing beta-TCP. They were randomly assigned to receive supplemented anterior plate (n = 33) or not (n = 29). The patients were followed up for 2 years postoperatively. The radiological and clinical outcomes were assessed during a 2-year follow-up. The results showed that the fusion rate (75.0%) 3 months after surgery in patients treated without anterior cervical plating was significantly lower than that (97.9%) with plate fixation (P < 0.05), but successful bone fusion was achieved in all patients of both groups at 6-month follow-up assessment. Patients treated without anterior plate fixation had 11 of 52 (19.2%) cage subsidence at last follow-up. No difference (P > 0.05) was found regarding improvement in spinal curvature as well as neck and arm pain, and recovery rate of JOA score at all time intervals between the two groups. Based on the findings of this study, interbody fusion cage containing beta-TCP following one- or two-level discectomy proved to be an effective treatment for cervical spondylotic radiculopathy and/or myelopathy. Supplemented anterior plate fixation can promote interbody fusion and prevent cage subsidence but do not improve the 2-year outcome when compared with those treated

  3. Near Continuum Velocity and Temperature Coupled Compressible Boundary Layer Flow over a Flat Plate

    NASA Astrophysics Data System (ADS)

    He, Xin; Cai, Chunpei

    2017-04-01

    The problem of a compressible gas flows over a flat plate with the velocity-slip and temperature-jump boundary conditions are being studied. The standard single- shooting method is applied to obtain the exact solutions for velocity and temperature profiles when the momentum and energy equations are weakly coupled. A double-shooting method is applied if these two equations are closely coupled. If the temperature affects the velocity directly, more significant velocity slip happens at locations closer to the plate's leading edge, and inflections on the velocity profiles appear, indicating flows may become unstable. As a consequence, the temperature-jump and velocity-slip boundary conditions may trigger earlier flow transitions from a laminar to a turbulent flow state.

  4. Column and Plate Compressive Strengths of Aircraft Structural Martials Extruded 0-1HTA Magnesium Alloy

    NASA Technical Reports Server (NTRS)

    Heimerl, George J; Niles, Donald E

    1947-01-01

    Column and plate compressive strengths of extruded 0-1HTA magnesium alloy were determined both within and beyond the elastic range from tests of flat end H-section columns and from local instability tests of H-, Z-, and channel section columns. These tests are part of an extensive research investigation to provide data on the structural strength of various aircraft materials. The results are presented in the form of curves and charts that are suitable for use in the design and analysis of aircraft structures.

  5. Metaphyseal locking plate as a definitive external fixator for treating open tibial fractures--clinical outcome and a finite element study.

    PubMed

    Ma, Ching-Hou; Wu, Chin-Hsien; Tu, Yuan-Kun; Lin, Ting-Sheng

    2013-08-01

    We evaluated both the outcome of using a locking plate as a definitive external fixator for treating open tibial fractures and, using finite element analysis, the biomechanical performance of external and internal metaphyseal locked plates in treating proximal tibial fractures. Eight open tibial patients were treated using a metaphyseal locked plate as a low-profile definitive external fixator. Then, finite element models of internal (IPF) as well as two different external plate fixations (EPFs) for proximal tibial fractures were reconstructed. The offset distances from the bone surface to the EPFs were 6 cm and 10 cm. Both axial stiffness and angular stiffness were calculated to evaluate the biomechanical performance of these three models. The mean follow-up period was 31 months (range, 18-43 months). All the fractures united and the mean bone healing time was 37.5 weeks (range, 20-52 weeks). All patients had excellent or good functional results and were walking freely at the final follow-up. The finite element finding revealed that axial stiffness and angular stiffness decreased as the offset distance from the bone surface increased. Compared to the IPF models, in the two EPF models, axial stiffness decreased by 84-94%, whereas the angular stiffness decreased by 12-21%. The locking plate used as a definitive external fixator provided a high rate of union. While the locking plate is not totally rigid, it is clinically stable and may be advisable for stiffness reduction of plating constructs, thus promoting fracture healing by callus formation. Our patients experienced a comfortable clinical course, excellent knee and ankle joint motion, satisfactory functional results and an acceptable complication rate.

  6. Carbon fiber reinforced plastic (CFRP) plates versus stainless steel dynamic compression plates in the treatment of fractures of the tibiae in dogs.

    PubMed

    Skirving, A P; Day, R; Macdonald, W; McLaren, R

    1987-11-01

    In a series of 14 dogs, fractures of both tibiae were caused by a "bone-breaker" designed in the authors' department and observed to produce a consistent and realistic canine fracture. One tibia was plated with a carbon fiber reinforced plastic (CFRP) plate and the other with a dynamic compression (DC) plate. Roentgenographic examination demonstrated healing of the CFRP-plated tibiae with abundant callus, and almost total remodeling of the fracture callus between ten and 20 weeks. Biomechanical testing by three-point bending revealed little difference between the strength of union of the fractures at 12-16 weeks. At 20 weeks, although the numbers were too small for statistical confirmation, the CFRP-plated tibiae were consistently stronger than the DC-plated tibiae.

  7. Outcome Analysis of Intra-Articular Scapula Fracture Fixation with Distal Radius Plate: A Multicenter Prospective Study

    PubMed Central

    Panigrahi, Ranajit; Madharia, Divya; Das, Dibya Singha; Samant, Saswat; Biswal, Manas Ranjan

    2016-01-01

    Background Scapula fractures occur in approximately 1% of all fractures and constitute about 3% - 5% of all injuries of the shoulder joint. Objectives This study aimed to evaluate the clinical outcomes of 20 surgically treated patients with displaced glenoid fractures after stabilization with distal radius plate. Methods Between 2012 and 2015, at 2 centers (HMCH & SHCE) of Bhubaneswar Odisha, we stabilized 20 scapular intra-articular fractures surgically with distal radius locking plate and studied the outcome of the surgeries. The outcome of the 20 fractures was determined using the Constant and Murley score. Both shoulders were assessed and the score on the injured side was given as a percentage of that on the uninjured side. Results The median score was 88% (mean 65%, range 30 to 100). The median score for strength was 21/25 (mean 19, range 0 to 25) and that for pain 11/15 (mean 11, range 5 to 15). The median functional score was 16/20 (mean 15, range 0 to 20). The mean range of active abduction of the shoulder was 135° (20 to 180), the mean range of flexion 138° (20 to 180) and the mean range of external rotation 38° (0 to 100). Five patients showed excellent result; 11 patients showed good result; three patients showed fair result and one patient had poor outcome according to the Constant-Murley score. A superficial infection settled with antibiotics after operation in one patient whose score at final follow-up was 96%. In one patient, delayed healing was reported because of infection. One patient with stiffness of the shoulder at six weeks underwent manipulation under anesthesia with a follow-up score of 81%. Conclusions Various fixation modalities have been described in the literature, however fixation of intra-articular fracture of glenoid with distal radius locking plate for articular reconstruction in the presented series provides good functional outcome with early restoration of the range of motion of the shoulder. PMID:28144606

  8. Fixation of unstable type II clavicle fractures with distal clavicle plate and suture button.

    PubMed

    Johnston, Peter S; Sears, Benjamin W; Lazarus, Mark R; Frieman, Barbara G

    2014-11-01

    This article reports on a technique to treat unstable type II distal clavicle fractures using fracture-specific plates and coracoclavicular augmentation with a suture button. Six patients with clinically unstable type II distal clavicle fractures underwent treatment using the above technique. All fractures demonstrated radiographic union at 9.6 (8.4-11.6) weeks with a mean follow-up of 15.6 (12.4-22.3) months. American Shoulder and Elbow Surgeons, Penn Shoulder Score, and Single Assessment Numeric Evaluation scores were 97.97 (98.33-100), 96.4 (91-99), and 95 (90-100), respectively. One patient required implant removal. Fracture-specific plating with suture-button augmentation for type II distal clavicle fractures provides reliable rates of union without absolute requirement for implant removal.

  9. Fixation of sternal fracture using absorbable plating system, three years follow-up

    PubMed Central

    Katballe, Niels; Pilegaard, Hans

    2015-01-01

    Sternal fractures occur due to severe chest wall trauma in a small number of patients. They are often conservatively treated. The surgical intervention, although controversial, is indicated in case of deformity, severe pain, and ventilatory complications. We report the first case where absorbable plate has been used to fix a traumatic fracture in a 42-year-old female. After 3 years, the patient is still free of symptoms and CT scanning reveals intact sternal bone structure. PMID:26101659

  10. Distal Radius Volar Rim Fracture Fixation Using DePuy-Synthes Volar Rim Plate

    PubMed Central

    Kachooei, Amir Reza; Tarabochia, Matthew; Jupiter, Jesse B.

    2016-01-01

    Background To assess the results of distal radius fractures with the involvement of the volar rim fixed with the DePuy-Synthes Volar Rim Plate. Case Description We searched for the patients with volar rim fracture and/or volar rim fractures as part of a complex fracture fixed with a volar rim plate. Ten patients met the inclusion criteria: three patients with type 23B3, six patients with type 23C, and one patient with very distal type 23A. The mean follow-up was 14 months (range: 2–26). Fractures healed in all patients. Of the three patients with isolated volar rim fractures (type 23B3), two patients had no detectable deficits in motion. These patients had an average Gartland and Werley score of 9 (range: 2–14). Of the other seven patients (six with type 23C and one with type 23A fracture), three patients healed with full range of motion and four had some deficits in range of motion. Two patients had excellent results, three had good results, and two had fair results using the Gartland and Werley categorical rating. One patient healed with a shortened radius and ulnar impingement requiring a second surgery for ulnar head resection arthroplasty. Literature Review Results after nonoperative treatment of volar rim fractures are not satisfactory and often require subsequent corrective osteotomy. Satisfactory outcomes are achieved when the fragments are well reduced and secured regardless of the device type. Clinical Relevance Volar rim plates give an adequate buttress of the volar radius distal to volar projection of the lunate facet and do not interfere with wrist mobility. Furthermore, the dorsal fragments can be fixed securely through the volar approach eliminating the need for a secondary posterior incision. However, patients should be informed of the potential problems and the need to remove the plate if symptoms develop. PMID:26855829

  11. Design criteria for steel tank shells in compression influenced by plate fabrication and welding distortion tolerances

    SciTech Connect

    Knoy, E.C.

    1994-12-31

    For almost 60 years, the design and construction of steel water storage tanks has most commonly been under the requirements of the American Water Works Association Standard D100 `Welded Steel Tanks for Water Storage.` For many years, the criteria for designing conical and double curved members under compression was not precisely defined by the AWWA Standard, as some designers considered the local buckling criteria to only be applicable to cylindrical tubular members. There have been varied opinions concerning design and tolerance philosophy. This paper will give an overview of these philosophies and will tell the importance of meeting these dimensional criteria. the method of calculating allowable deformations and measuring as-built deformations will be shown. Several examples of actual failures and laboratory and computer-simulated testing will be shown, leaving the attendee with a visual message of the importance of complying with the industry-accepted design, assembly, and welding techniques. A discussion of the safety of welded steel structures in public areas will also be included in the presentation. Engineering concern for the adequacy of current standards for the proper design and construction of composite tanks made of reinforced concrete and steel plate will be outlined. The reader will be made aware of the need for proper design, fabrication, and construction of tubular steel plate members subject to compressive loads.

  12. Analysis of behavior of simply supported flat plates compressed beyond the buckling load into the plastic range

    NASA Technical Reports Server (NTRS)

    Mayers, J; Budiansky, Bernard

    1955-01-01

    An analysis is presented of the postbuckling behavior of a simply supported square flat plate with straight edges compressed beyond the buckling load into the plastic range. The method of analysis involves the application of a variational principle of the deformation theory of plasticity in conjunction with computations carried out on a high-speed calculating machine. Numerical results are obtained for several plate proportions and for one material. The results indicate plate strengths greater than those that have been found experimentally on plates that do not satisfy straight-edge conditions. (author)

  13. Morphologic evaluation of cervical spine anatomy with computed tomography: anterior cervical plate fixation considerations.

    PubMed

    Kwon, Brian K; Song, Frederick; Morrison, William B; Grauer, Jonathan N; Beiner, John M; Vaccaro, Alexander R; Hilibrand, Alan S; Albert, Todd J

    2004-04-01

    The computed tomography (CT) studies of the cervical spine from 50 males and 50 females were reviewed to provide morphometric data on a variety of anatomic parameters relevant to anterior cervical reconstruction and fixation. Measurements were made of the vertebral body width and midsagittal anteroposterior (AP) diameter and the distance between the medial borders of the longus coli muscles. Distances between adjacent endplates were also measured, both at their midpoint and at the anterior margin. Widths of the vertebral bodies measure 24.6 +/- 2.4 and 23.0 +/- 2.4 mm in males and females, respectively, with the narrowest measuring 17 and 14, respectively. The average midsagittal AP diameter of each vertebral body in males was approximately 17-18 mm, with the smallest AP diameter measured to be 13 mm. The average midsagittal AP diameter of each vertebral body in females was approximately 15-16 mm, with the smallest being 10 mm. CT scanning provides excellent osseous detail for the measurement of such parameters, and with its widespread use in the evaluation of cervical disorders, large numbers of patients can be reviewed.

  14. [Humerus varus: correction by proximal valgus osteotomy with precontourned plate fixation in children].

    PubMed

    Tallón-López, J; Domínguez-Amador, J J; Andrés-García, J A

    2014-01-01

    Varus deformity of the proximal humerus in children is a little known pathology due to its low incidence of presentation. Progress has been made in recent years in understanding the possible etiology and pathophysiological causes. Radiological criteria for diagnosis and functional impairment that occurs have also been defined. However, there are few reports in the literature about the surgical treatment of this deformity in children. In this paper we present a case of surgical treatment of this deformity by corrective osteotomy fixed with precontoured external maleolar plate osteosynthesis.

  15. Results of Arthroscopic Ankle Arthrodesis with Fixation Using Two Parallel Headless Compression Screws in a Heterogenic Group of Patients

    PubMed Central

    Kolodziej, Lukas; Sadlik, Boguslaw; Sokolowski, Sebastian; Bohatyrewicz, Andrzej

    2017-01-01

    Background: As orthopedic surgeons become skilled in ankle arthroscopy technique and evidence -based data is supporting its use, arthroscopic ankle arthrodesis (AAA) will likely continue to increase, but stabilization methods have not been described clearly. We present a technique for two parallel 7.3-mm headless compression screws fixation (HCSs) for AAA in cases of ankle arthritis with different etiology, both traumatic and non-traumatic, including neuromuscular and inflammatory patients. Materials and Methods: We retrospectively verified 24 consecutive patients (25 ankles) who underwent AAA between 2011 and 2015. The average follow-up was 26 months (range 18 to 52 months). Arthrodesis was performed in 16 patients due to posttraumatic arthritis (in 5 as a sequela of pilon, 6 ankles, 3 tibia fractures, and 2 had arthritis due to chronic instability after lateral ligament injury), in 4 patients due to neuromuscular ankle joint deformities, and in 4 patients due to rheumatoid arthritis. Results: Fusion occurred in 23 joints (92%) over an average of 12 weeks (range 6 to 18 weeks). Ankle arthrodesis was not achieved in 2 joints (8%), both in post-pilon fracture patients. The correct foot alignment was not achieved in 4 feet (16%). None of the treated patients required hardware removal. Conclusion: The presented technique was effective in achieving a high fusion rate in a variety of diseases, decreasing intra- and post-operative hardware complications while maintaining adequate bone stability.

  16. The Northern Caribbean Plate Boundary Offshore Hispaniola: Strike-slip and Compressive Tectonic Processes

    NASA Astrophysics Data System (ADS)

    Corbeau, J.; Rolandone, F.; Leroy, S. D.; Mercier De Lepinay, B. F.; Meyer, B.; Ellouz, N.

    2014-12-01

    The boundary between the Caribbean plate and the North American plate is transpressive due to the oblique collision between these two plates. The transpressive movement is partitioned and accommodated in the Hispaniola region along two left-lateral strike-slip structures surrounding a fold-and-thrust belt. New multibeam bathymetry data and multichannel seismic reflection profiles have been recently collected during the Haiti-SIS and Haiti-SIS 2 cruises, along part of the northern Caribbean plate boundary between Cuba, Jamaica and Hispaniola. From the north to the south, three types of deformations are observed. In the Windward Passage, the analysis of the data set reveals that the movement on the Oriente fault between Cuba and Hispaniola is purely left-lateral strike-slip according to the GPS measurements. In the Gonave basin, west of Hispaniola, the deformation is compressive. A series of folds is identified and moves toward the southwest. The Enriquillo-Plantain-Garden Fault (EPGF) is localized in the Jamaica Passage, between Jamaica and Hispaniola. The analysis of the data set reveals that the left-lateral EPGF recently intersects inherited basins from the eastern Cayman Trough margin. The study of the actual EPGF active trace shows that this fault moves with a pure strike-slip component, at least in its western part: the presence of a little push-up structure and a set of three en echelon folds is highlighting in the western part of the Jamaica Passage. The shortening rate in the inherited basins crossed by the EPGF increases from west to east (5.8% to 8.5%), indicating that a thrusting component is also accommodated around the EPGF.

  17. Large-deflection theory for end compression of long rectangular plates rigidly clamped along two edges

    NASA Technical Reports Server (NTRS)

    Levy, Samuel; Krupen, Philip

    1943-01-01

    The von Karman equations for flat plates are solved beyond the buckling load up to edge strains equal to eight time the buckling strain, for the extreme case of rigid clamping along the edges parallel to the load. Deflections, bending stresses, and membrane stresses are given as a function of end compressive load. The theoretical values of effective width are compared with the values derived for simple support along the edges parallel to the load. The increases in effective width due to rigid clamping drops from about 20 percent near the buckling strain to about 8 percent at an edge strain equal to eight times the buckling strain. Experimental values of effective width in the elastic range reported in NACA Technical Note No. 684 are between the theoretical curves for the extremes of simple support and rigid clamping.

  18. Percutaneous compression plating versus gamma nail for the treatment of pertrochanteric hip fractures

    PubMed Central

    Antonini, Guido; Delle Rose, Giacomo; Crippa, Cornelio

    2008-01-01

    The objective of this study is to compare percutaneous compression plating (PCCP) device with standard gamma nail (GN). A sample was prospectively followed and compared to a historical cohort: 82 intertrochanteric hip fractures in 81 patients treated with PCCP in 2004 versus 51 hip fractures treated with GN in 2003 (AO type 31A1, 31 A2). The main outcome measures were: surgery times, blood loss (Hb serum level and transfusions), complication, costs, for a 1-year follow-up. The minimally invasive PCCP technique resulted in a lower blood loss and consequently lower transfusion need (statistically significant), fewer implant-related complications and comparable surgery times. Overall surgical costs were lower for a comparable outcome in terms of healing and surgical time. PMID:18427918

  19. External Fixator for Maintaining Reduction Before Volar Plating: A Simple Treatment Method for Association of Osteosynthesis Type C3 Distal Radius Fracture.

    PubMed

    Tsai, Chun-Hao; Hsu, Chin-Jung; Wang, Ta-I; Fong, Yi-Chin; Hsu, Horng-Chaung; Lin, Tsung-Li

    2016-03-01

    Volar plating for Association of Osteosynthesis type C3 distal radius fractures involves more time and more radiation exposure because it is extremely difficult to simultaneously maintain the reduction and restore the congruity of the articular surface. The authors present a technique of maintaining the acceptable reduction by using an external fixator followed by open volar plating for restoring articular congruity. A consecutive series of 96 Association of Osteosynthesis type C3 distal radius fractures treated with the technique were retrospectively reviewed between January 2004 and December 2012. The technique makes surgery simpler and more effective, and reduces radiation exposure.

  20. Study of compression settlement of a three-layer rigid-plastic strip between parallel plates

    NASA Astrophysics Data System (ADS)

    Aleksandrov, S. E.; Goldstein, R. V.

    2014-11-01

    The process of compression settlement of a three-layer strip between parallel plates is investigated under the plane strain conditions. The inner layer of the strip is assumed to be made of a rigid-plastic hardening material, and the two outer layers are assumed to be ideally rigid-plastic. The boundary value problem has two symmetry axes. It is assumed that the strip thickness is much less than its width. The boundary conditions at the strip edge and at the center are satisfied in integral form. Two friction regimes, i.e., sliding and adhesion, are possible on the surface of contact between the strip and the plates and on the interface between the layers. It is shown that the general structure of the solution depends on the regimes realized at the moment. In particular, one of the layers can remain rigid at a certain stage of the deformation process. The differential equations are stated which permit exactly determining the conditions of the friction regime change and the state of each layer (rigid or plastic); these equations must be solved numerically. For some values of parameters of the boundary value problem, the velocity field is singular near one or both surfaces of friction. In these cases, it is necessary to calculate the strain rate intensity coefficient whose value probably controls the process of formation of a narrow layer with strongly changed properties near the corresponding surface of friction.

  1. Poor relation between biomechanical and clinical studies for the proximal femoral locking compression plate.

    PubMed

    Viberg, Bjarke; Rasmussen, Katrine M V; Overgaard, Søren; Rogmark, Cecilia

    2017-03-13

    Background and purpose - The proximal femur locking compression plate (PF-LCP) is a new concept in the treatment of hip fractures. When releasing new implants onto the market, biomechanical studies are conducted to evaluate performance of the implant. We investigated the relation between biomechanical and clinical studies on PF-LCP. Methods - A systematic literature search of relevant biomechanical and clinical studies was conducted in PubMed on December 1, 2015. 7 biomechanical studies and 15 clinical studies were included. Results - Even though the biomechanical studies showed equivalent or higher failure loads for femoral neck fracture, the clinical results were far worse, with a 37% complication rate. There were no biomechanical studies on pertrochanteric fractures. Biomechanical studies on subtrochanteric fractures showed that PF-LCP had a lower failure load than with proximal femoral nail, but higher than with angled blade plate. 4 clinical studies had complication rates less than 8% and 9 studies had complication rates between 15% and 53%. Interpretation - There was no clear relation between biomechanical and clinical studies. Biomechanical studies are generally inherently different from clinical studies, as they examine the best possible theoretical use of the implant without considering the long-term outcome in a clinical setting. Properly designed clinical studies are mandatory when introducing new implants, and they cannot be replaced by biomechanical studies.

  2. Critical Compressive Stress for Flat Rectangular Plates Supported Along All Edges and Elastically Restrained Against Rotation along the Unloaded Edges

    NASA Technical Reports Server (NTRS)

    Lundquist, Eugene E; Stowell, Elbridge Z

    1942-01-01

    A chart is presented for the values of the coefficient in the formula for the critical compressive stress at which buckling may be expected to occur in flat rectangular plates supported along all edges and, in addition, elastically restrained against rotation along the unloaded edges. The mathematical derivations of the formulas required in the construction of the chart are given.

  3. Treatment of unstable distal radius fractures: non-invasive dynamic external fixator versus volar locking plate – functional and radiological outcome in a prospective case-controlled series

    PubMed Central

    Bajwa, Ali S.; Rammappa, Manju; Lee, Ling; Nanda, Rajesh

    2015-01-01

    Introduction: Distal radius fracture (DRF) is a common injury and various treatment modalities including open reduction and internal fixation (ORIF) with volar locking plate are available. More recently, a non-invasive external fixator has been used. Aims: To prospectively compare the use of a non-invasive external fixator with early dynamisation for DRF against ORIF with volar locking plate control group. Methods: Consecutive patients with closed DRF were included in a prospective case-controlled study. Patients were assigned to non-invasive external fixator or ORIF. Minimum follow-up was two years. Follow-up was at weeks 2, 4, 6, 8, 12, 26 and at one and two-year post-operatively. The outcome measures included demographic details, injury mechanism, AO fracture type, risk factors, body mass index (BMI), ulnar styloid fracture and dorsal comminution, radiographs, grip strength and DASH score. Results: Consecutive 50 patients were treated either with non-invasive external fixator (25/50) or with ORIF (25/50) and the mean age of the two groups was 53 years (SD 17.1) and 49 years (SD 19.5), respectively. Demographics were matched in two groups. In the non-invasive external fixator group, there were 10 AO Type-A, 5 Type-B and 10 Type-C fractures. The ORIF group included 8 Type-A, 6 Type-B and 11 Type-C fractures. The mean DASH score at three-months and one-year post-injury in non-invasive fixator group was 12.2 (SD 3.1) and 3.5 (SD 0.7), respectively, significantly greater than those of ORIF group 14.5 (SD 5.6) and 11.2 (SD 4.4), respectively (p < 0.05). Conclusion: DRF treated with non-invasive external fixator can give functional results superior to ORIF at three-months and the trend is maintained at one and two-year post-operatively. PMID:27163089

  4. The Clinical Usefulness of Ultrasound-Aided Fixation Using an Absorbable Plate System in Patients with Zygomatico-Maxillary Fracture

    PubMed Central

    Park, Jun Hyung

    2013-01-01

    Background Ultrasound-aided fixation is a recently developed alternative method of treatment of zygomatico-maxillary (ZM) fracture, and it can resolve the problems of excessive torsion force and subsequent fractures of screws. We conducted this study to evaluate the clinical usefulness of ultrasound-aided fixation as compared with the conventional fixation method using a drill and an expander in patients with ZM fracture. Methods We conducted a retrospective study in 35 patients with ZM fracture who had been treated at our hospital during a period ranging from March of 2008 to December of 2010. We divided them into two groups: an ultrasound-aided fixation group, comprising 13 patients who underwent ultrasound-aided fixation (SonicWeld Rx, KLS Martin), and a conventional group, comprising 22 patients who underwent conventional fixation (Biosorb FX, Linvatec Biomaterials Ltd.). We compared such variables as sex, direction, age at operation, follow-up period, operation duration, number of fixed holes, and time to discharge between the two groups. Results The ultrasound-aided fixation reduced the operation duration by about 30 minutes as compared with that of conventional fixation. There was no significant difference in follow-up period, number of fixed holes, or time to discharge between the two groups. Furthermore, there were no complications in either group. Conclusions The ultrasound-aided fixation of fractured ZM bone using an absorbable implant system is safe and effective in promptly reducing the bone fracture and providing satisfactory cosmetic outcomes over time. PMID:23898427

  5. Bioabsorbable bone fixation plates for X-ray imaging diagnosis by a radiopaque layer of barium sulfate and poly(lactic-co-glycolic acid).

    PubMed

    Choi, Sung Yoon; Hur, Woojune; Kim, Byeung Kyu; Shasteen, Catherine; Kim, Myung Hun; Choi, La Mee; Lee, Seung Ho; Park, Chun Gwon; Park, Min; Min, Hye Sook; Kim, Sukwha; Choi, Tae Hyun; Choy, Young Bin

    2015-04-01

    Bone fixation systems made of biodegradable polymers are radiolucent, making post-operative diagnosis with X-ray imaging a challenge. In this study, to allow X-ray visibility, we separately prepared a radiopaque layer and attached it to a bioabsorbable bone plate approved for clinical use (Inion, Finland). We employed barium sulfate as a radiopaque material due to the high X-ray attenuation coefficient of barium (2.196 cm(2) /g). The radiopaque layer was composed of a fine powder of barium sulfate bound to a biodegradable material, poly(lactic-co-glycolic acid) (PLGA), to allow layer degradation similar to the original Inion bone plate. In this study, we varied the mass ratio of barium sulfate and PLGA in the layer between 3:1 w/w and 10:1 w/w to modulate the degree and longevity of X-ray visibility. All radiopaque plates herein were visible via X-ray, both in vitro and in vivo, for up to 40 days. For all layer types, the radio-opacity decreased with time due to the swelling and degradation of PLGA, and the change in the layer shape was more apparent for layers with a higher PLGA content. The radiopaque plates released, at most, 0.5 mg of barium sulfate every 2 days in a simulated in vitro environment, which did not appear to affect the cytotoxicity. The radiopaque plates also exhibited good biocompatibility, similar to that of the Inion plate. Therefore, we concluded that the barium sulfate-based, biodegradable plate prepared in this work has the potential to be used as a fixation device with both X-ray visibility and biocompatibility.

  6. Mechanical evaluation of two canine iliac fracture fixation systems.

    PubMed

    Vangundy, T E; Hulse, D A; Nelson, J K; Boothe, H W

    1988-01-01

    Twenty-three canine pelves were tested bilaterally to determine the stiffness and strength of intact ilium and stabilized oblique iliac osteotomies that simulated a common clinical fracture. Fixation systems tested were three 4.0 mm cancellous screws inserted ventral to dorsal across the osteotomy site and one laterally placed five hole 3.5 mm dynamic compression plate. Specimens were mechanically tested to failure under torsional, axial, or axial plus bending loads. Lag screw fixation was stiffer and stronger than plate fixation in all testing modes. The differences were statistically significant (p less than .05) in the torsional and axial plus bending loading modes. Fatigue testing was performed on implanted specimens with low-level cyclic loading under axial plus bending loading conditions. Physiologic loading conditions failed to produce mechanical failure of either fixation system after 100,000 cycles.

  7. Magnetically launched flyer plate technique for probing electrical conductivity of compressed copper

    NASA Astrophysics Data System (ADS)

    Cochrane, K. R.; Lemke, R. W.; Riford, Z.; Carpenter, J. H.

    2016-03-01

    The electrical conductivity of materials under extremes of temperature and pressure is of crucial importance for a wide variety of phenomena, including planetary modeling, inertial confinement fusion, and pulsed power based dynamic materials experiments. There is a dearth of experimental techniques and data for highly compressed materials, even at known states such as along the principal isentrope and Hugoniot, where many pulsed power experiments occur. We present a method for developing, calibrating, and validating material conductivity models as used in magnetohydrodynamic (MHD) simulations. The difficulty in calibrating a conductivity model is in knowing where the model should be modified. Our method isolates those regions that will have an impact. It also quantitatively prioritizes which regions will have the most beneficial impact. Finally, it tracks the quantitative improvements to the conductivity model during each incremental adjustment. In this paper, we use an experiment on Sandia National Laboratories Z-machine to isentropically launch multiple flyer plates and, with the MHD code ALEGRA and the optimization code DAKOTA, calibrated the conductivity such that we matched an experimental figure of merit to +/-1%.

  8. Buckling Of Long Compression-Loaded Anisotropic Plates Restrained Against Inplane Lateral and Shear Deformations

    NASA Technical Reports Server (NTRS)

    Nemeth, Michael P.

    2003-01-01

    An approach for synthesizing buckling results and behavior for thin balanced and unbalanced symmetric laminates that are subjected to uniform axial compression loads and elastically restrained against inplane expansion, contraction, and shear deformation is presented. This approach uses a nondimensional analysis for infinitely long, flexurally anisotropic plates (coupling between bending and twisting) that are subjected to combined mechanical loads and is based on nondimensional parameters. In addition, nondimensional loading parameters are derived that account for the effects of the elastic inplane deformation restraints, membrane orthotropy, and membrane anisotropy on the induced prebuckling stress state. The loading parameters are used to determine buckling coefficients that include the effects of flexural orthotropy and flexural anisotropy. Many results are presented, for some selected laminates, that are intended to facilitate a structural designer's transition to the use of the generic buckling design curves that are presented and discussed in the paper. Several buckling response curves are presented that provide physical insight into the behavior for combined loads, in addition to providing useful design data. An example is presented that demonstrates the use of the generic design curves, which are applicable to a wide range of laminate constructions. The analysis approach and generic results indicate the effects and characteristics of laminate orthotropy and anisotropy in a very general and unifying manner.

  9. A systematic review of open reduction and internal fixation of periprosthetic femur fractures with or without allograft strut, cerclage, and locked plates.

    PubMed

    Moore, Ryan E; Baldwin, Keith; Austin, Matthew S; Mehta, Samir

    2014-05-01

    Few comparative studies exist for open reduction and internal fixation of Vancouver B1 and C fractures. We therefore performed a systematic review of fractures treated with or without an allograft strut, and using various fixation techniques. Thirty-seven manuscripts including 682 fractures were identified between 1992 and 2012. Percent union was similar for Vancouver B1 fractures treated with or without an allograft strut (90.7% vs. 91.5%). Time to union (4.4 vs. 6.6 months) and deep infection (3.8% vs. 8.3%) were increased with use of allograft struts. Percent union and time to union were unaffected by plate type or use of cerclage. We conclude that due to increased infection and time to union, allograft struts should be used cautiously during operative treatment of Vancouver B1 factures.

  10. Fatigue damage prognosis of internal delamination in composite plates under cyclic compression loadings using affine arithmetic as uncertainty propagation tool

    NASA Astrophysics Data System (ADS)

    Gbaguidi, Audrey J.-M.

    Structural health monitoring (SHM) has become indispensable for reducing maintenance costs and increasing the in-service capacity of a structure. The increased use of lightweight composite materials in aircraft structures drastically increased the effects of fatigue induced damage on their critical structural components and thus the necessity to predict the remaining life of those components. Damage prognosis, one of the least investigated fields in SHM, uses the current damage state of the system to forecast its future performance by estimating the expected loading environments. A successful damage prediction model requires the integration of technologies in areas like measurements, materials science, mechanics of materials, and probability theories, but most importantly the quantification of uncertainty in all these areas. In this study, Affine Arithmetic is used as a method for incorporating the uncertainties due to the material properties into the fatigue life prognosis of composite plates subjected to cyclic compressive loadings. When loadings are compressive in nature, the composite plates undergo repeated buckling-unloading of the delaminated layer which induces mixed modes I and II states of stress at the tip of the delamination in the plates. The Kardomateas model-based prediction law is used to predict the growth of the delamination, while the integration of the effects of the uncertainties for modes I and II coefficients in the fatigue life prediction model is handled using Affine arithmetic. The Mode I and Mode II interlaminar fracture toughness and fatigue characterization of the composite plates are first experimentally studied to obtain the material coefficients and fracture toughness, respectively. Next, these obtained coefficients are used in the Kardomateas law to predict the delamination lengths in the composite plates while using Affine Arithmetic to handle their uncertainties. At last, the fatigue characterization of the composite plates during

  11. Experimental and theoretical study of the buckling of narrow thin plates on an elastic foundation under compression

    NASA Astrophysics Data System (ADS)

    Kurguzov, V. D.; Demeshkin, A. G.

    2016-05-01

    The paper describes the processes of elastic deformation of thin films under mechanical loading. The film is modeled longitudinally by a compressed plate arranged on an elastic foundation. A computer model of the buckling of the narrow thin plate with a delamination portion located on an elastic foundation is constructed. This paper also touches upon the supercritical behavior of the plate-substrate system. The experiments on the axial compression of a metal strip adhered to a rubber plate are performed, and 2 to 7 buckling modes are obtained therein. The critical loads and buckling modes obtained in the numerical calculations are compared with the experimental data. It is shown that there is the possibility of progressive delamination of the metal plate from the foundation if the critical load is exceeded. It is found that the use of the proposed approach, which, in contrast to other approaches, accounts for the elastic deformation of the substrate, causes the dependence between the critical bending stress and the stiffness of the foundation.

  12. ENDOCHONDRAL GROWTH IN GROWTH PLATES OF THREE SPECIES AT TWO ANATOMICAL LOCATIONS MODULATED BY MECHANICAL COMPRESSION AND TENSION

    PubMed Central

    Stokes, Ian A.F.; Aronsson, David D.; Dimock, Abigail N.; Cortright, Valerie; Beck., Samantha

    2006-01-01

    SUMMARY Purpose Sustained mechanical loading alters longitudinal growth of bones, and this growth sensitivity to load has been implicated in progression of skeletal deformities during growth. The objective of this study was to quantify the relationship between altered growth and different magnitudes of sustained altered stress in a diverse set of non-human growth plates. Methods The sensitivity of endochondral growth to differing magnitudes of sustained compression or distraction stress was measured in growth plates of three species of immature animals (rats, rabbits, calves) at two anatomical locations (caudal vertebra and proximal tibia) with two different ages of rats and rabbits. An external loading apparatus was applied for eight days and growth was measured as the distance between fluorescent markers administered 24 and 48 hours prior to euthanasia. Results An apparently linear relationship between stress and percentage growth modulation (percent difference between loaded and control growth plates) was found, with distraction accelerating growth and compression slowing growth. The growth-rate sensitivity to stress was between 9.2 and 23.9% per 0.1 MPa for different growth plates, and averaged 17.1% per 0.1 MPa. The growth-rate sensitivity to stress differed between vertebrae and the proximal tibia (15 and 18.6 percent per 0.1 MPa respectively). The range of control growth rates of different growth plates was large (30 microns/day for rat vertebrae to 366 microns/day for rabbit proximal tibia). Conclusions The relatively small differences in growth-rate sensitivity to stress for a diverse set of growth plates suggests that these results might be generalized to other growth plates, including human. These data may be applicable to planning the management of progressive deformities in patients having residual growth. PMID:16705695

  13. Endochondral growth in growth plates of three species at two anatomical locations modulated by mechanical compression and tension.

    PubMed

    Stokes, Ian A F; Aronsson, David D; Dimock, Abigail N; Cortright, Valerie; Beck, Samantha

    2006-06-01

    Sustained mechanical loading alters longitudinal growth of bones, and this growth sensitivity to load has been implicated in progression of skeletal deformities during growth. The objective of this study was to quantify the relationship between altered growth and different magnitudes of sustained altered stress in a diverse set of nonhuman growth plates. The sensitivity of endochondral growth to differing magnitudes of sustained compression or distraction stress was measured in growth plates of three species of immature animals (rats, rabbits, calves) at two anatomical locations (caudal vertebra and proximal tibia) with two different ages of rats and rabbits. An external loading apparatus was applied for 8 days, and growth was measured as the distance between fluorescent markers administered 24 and 48 h prior to euthanasia. An apparently linear relationship between stress and percentage growth modulation (percent difference between loaded and control growth plates) was found, with distraction accelerating growth and compression slowing growth. The growth-rate sensitivity to stress was between 9.2 and 23.9% per 0.1 MPa for different growth plates and averaged 17.1% per 0.1 MPa. The growth-rate sensitivity to stress differed between vertebrae and the proximal tibia (15 and 18.6% per 0.1 MPa, respectively). The range of control growth rates of different growth plates was large (30 microns/day for rat vertebrae to 366 microns/day for rabbit proximal tibia). The relatively small differences in growth-rate sensitivity to stress for a diverse set of growth plates suggest that these results might be generalized to other growth plates, including human. These data may be applicable to planning the management of progressive deformities in patients having residual growth.

  14. Opening-wedge osteotomy, allografting with dual buttress plate fixation for severe genu recurvatum caused by partial growth arrest of the proximal tibial physis: a case report.

    PubMed

    Chen, Liang-Chin; Chan, Yi-Sheng; Wang, Ching-Jen

    2004-07-01

    Injuries to the proximal tibial physis are among the least common epiphyseal injuries. We present a case of severe genu recurvatum deformity (45 degrees) with leg length discrepancy (4 cm) following a neglected proximal tibial physeal injury incurred 6 years previously. The 16-year-old patient was successfully treated by open-wedge osteotomy, allograft reconstruction, and dual buttress plate fixation. At 3 years' follow-up, the patient was asymptomatic, fully active with a full range of motion (0 - 140 degrees) of the leg, and equal leg lengths. There were no signs of genu recurvatum clinically.

  15. Charts relating the compressive buckling stress of longitudinally supported plates to the effective deflectional and rotational stiffness of the supports

    NASA Technical Reports Server (NTRS)

    Anderson, Roger A; Semonian, Joseph W

    1954-01-01

    A stability analysis is made of a long flat rectangular plate subjected to a uniform longitudinal compressive stress and supported along its longitudinal edges and along one or more longitudinal lines by elastic line supports. The elastic supports possess deflectional and rotational stiffness. Such configuration is an idealization of the compression cover skin and internal structure of a wing and tail surfaces. The results of the analysis are presented in the form of charts in which the buckling-stress coefficient is plotted against the buckle length of the plate for a wide range of support stiffnesses. The charts make possible the determination of the compressive buckling stress of plates supported by members whose stiffness may or may not be defined by elementary beam bending and twisting theory but yet whose effective restraint is amenable to evaluation. The deflectional and rotational stiffness provided by longitudinal stiffeners and full-depth webs is discussed and numerical examples are given to illustrate the application of the charts to the design of wing structures.

  16. Effects of adding injection-compression to rapid heat cycle molding on the structure of a light guide plate

    NASA Astrophysics Data System (ADS)

    Hong, Seokkwan; Min, Inki; Yoon, Kyunghwan; Kang, Jeongjin

    2014-01-01

    This study investigates the effects of adding injection-compression to rapid heat cycle molding (RHCM) (rapid heat cycle injection-compression molding (RICM)) on the physical quality and optical anisotropy of a molded light guide plate (LGP). Transcription ratio of microstructure, uniformity of part thickness and birefringence were experimentally evaluated on a 7 inch LGP of nominal thickness of 1.12 mm (including a microstructure array of 30 µm diameter and 14 µm height). The designed mold was equipped with rapid heating and compressing facilities and a microstructured nickel stamper was fabricated by UV LIGA process. In addition, to investigate the efficacy of RICM, experiments involving conventional injection molding (CIM), ICM, and RHCM were conducted in parallel with RICM using the same mold. RHCM and RICM yielded excellent transcription ratios for the microstructure, while CIM and RICM provided high thickness uniformity and low birefringence. Thus, RICM obtains high transcription ratio of microstructure, uniform thickness and low birefringence.

  17. Buckling and postbuckling behavior of square compression-loaded graphite-epoxy plates with circular cutouts

    NASA Technical Reports Server (NTRS)

    Nemeth, Michael P.

    1990-01-01

    Results are presented for unidirectional (0, 10)(sub s) and (90,10)(sub s) plates, ((0/90)(sub 5)(sub s)) plates, and for aluminum plates. Results are also presented for ((+/- theta)(sub 6)(sub s)) angle-ply plates for values of theta = 30, 45, and 60 degrees. The results indicate that the change in axial stiffness of a plate at buckling is strongly dependent upon cutout size and plate orthotropy. The presence of a cutout gives rise to an internal load distribution that changes, sometimes dramatically, as a function of cutout size coupled with the plate orthotropy. In the buckled state, the role of orthotropy becomes more significant since bending in addition to membrane orthotropy is present. Most of the plates with cutouts exhibited less postbuckling stiffness than the corresponding plate without a cutout, and the postbuckling stiffness decreased with increasing cutout size. However, some of the highly orthotropic plates with cutouts exhibited more postbuckling stiffness than the corresponding plate without a cutout. These results suggest the possibility of tailoring the cutout size and the stacking sequence of a composite plate to optimize postbuckling stiffness. It was found that plates with large radius cutouts do exhibit some postbuckling strength. The results also indicate that a cutout can influence modal interaction in a plate. Specifically, results are presented that show a plate with a relatively small cutout buckling at a higher load than the corresponding plate without a cutout, due to modal interaction. Other results are presented that indicate the presence of nonlinear prebuckling deformations, due to material nonlinearity, in the angle-ply plates with theta = 45 and 60 degrees. The nonlinear prebuckling deformations are more pronounced in the plates with theta = 45 degrees and become even more pronounced as the cutout size increases. Results are also presented that show how load-path eccentricity due to improper machining of the test specimens

  18. Fuel cell plates with skewed process channels for uniform distribution of stack compression load

    DOEpatents

    Granata, Jr., Samuel J.; Woodle, Boyd M.

    1989-01-01

    An electrochemical fuel cell includes an anode electrode, a cathode electrode, an electrolyte matrix sandwiched between electrodes, and a pair of plates above and below the electrodes. The plate above the electrodes has a lower surface with a first group of process gas flow channels formed thereon and the plate below the electrodes has an upper surface with a second group of process gas flow channels formed thereon. The channels of each group extend generally parallel to one another. The improvement comprises the process gas flow channels on the lower surface of the plate above the anode electrode and the process gas flow channels on the upper surface of the plate below the cathode electrode being skewed in opposite directions such that contact areas of the surfaces of the plates through the electrodes are formed in crisscross arrangements. Also, the plates have at least one groove in areas of the surfaces thereof where the channels are absent for holding process gas and increasing electrochemical activity of the fuel cell. The groove in each plate surface intersects with the process channels therein. Also, the opposite surfaces of a bipolar plate for a fuel cell contain first and second arrangements of process gas flow channels in the respective surfaces which are skewed the same amount in opposite directions relative to the longitudinal centerline of the plate.

  19. Dynamic Hip Screw with Trochanteric Stablization Plate Fixation of Unstable Inter-Trochanteric Fractures: A Prospective Study of Functional and Radiological Outcomes

    PubMed Central

    Shetty, Ashwin; Sadasivan, Anand Kumar; Hegde, Anoop

    2016-01-01

    Introduction Management of unstable intertrochanteric fractures have posed a unique challenge to orthopaedicians over years. Several surgical techniques and implants have been developed for the same. Fractures of the lateral wall have been considered as the major cause of femoral medialization after fixation by Dynamic Hip Screw (DHS). Studies have shown that supplementation of trochanteric stabilization plate reduces the incidence of femoral medialization. Aim To assess the radiological union and hip function after fixation of unstable intertrochanteric fractures with DHS and Trochanteric Stabilization Plate (TSP). Materials and Methods A prospective study was conducted with a total of 32 patients between age groups of 30-70 years with Evan Jensen unstable and very unstable type of intertrochanteric fractures, between August 2013 to March 2015 in the Department of Orthopaedics ARS Hospital, Tirupur, Tamil Nadu, India. They underwent open reduction and DHS and TSP fixation. They were started on full weight bearing mobilization on post op day three. They were reviewed at post-op weeks 3,6,12 and 24. Hip mobilization and rehabilitation exercises were instituted during course of reviews. Radiographs were taken to assess fracture union and hip function was evaluated during follow-ups. At the end of 24 weeks, degree of radiographic union was scored as per Radiological Union Score for Hip (RUSH). Hip function was scored with Harris hip score. Analyses were done using frequency and proportions. Chi-square tests were used to assess the test of association. Results Fifteen patients had RUSH scores between 10-20 and 17 patients had scores between 20-30 points. RUSH score had mean of 21.03+/- 2.132 points. 9 of 32 patients had excellent results as per Harris hip score, 10 had good, nine had fair and four had poor. On comparison of Harris hip score with RUSH score: Interval between 10-20 points, of 15 patients; two had excellent results, five had good, five had fair and three

  20. Significance of a Pronator Quadratus–Sparing Approach for Volar Locking Plate Fixation of Comminuted Intra-articular Fractures of the Distal Radius

    PubMed Central

    Itoh, Soichiro; Yumoto, Myu; Kanai, Misa; Yoshida, Wataru; Yoshioka, Taro

    2016-01-01

    Background: The preservation of the integrity of the pronator quadratus (PQ) muscle is expected to have many benefits, particularly in cases of highly comminuted intra-articular fractures of the distal radius. Therefore, we examined the significance of a PQ muscle–sparing approach for volar locking plate (VLP) fixation of these types of fractures. Methods: Sixty-five patients who sustained AO Foundation and Orthopaedic Trauma Association (AO/OTA) type C2 and C3 distal radius fractures were treated with VLP fixation using either a PQ muscle release and repair (PQ-releasing group, n = 30) or a PQ muscle–sparing approach (PQ-sparing group, n = 35). Radiographic parameters, active range of motion (ROM), percentage of the grip power of the injured hand compared with that of the opposite hand, wrist pain visual analog scale (VAS) score, and Quick Disability of the Arm, Shoulder, and Hand (DASH) score (disability/symptom) were evaluated monthly up to 12 months after surgery. Results: The mean VAS score was significantly lower in the PQ-sparing group at 2, 3, and 4 months postoperatively than in the PQ-releasing group. Furthermore, the mean Quick DASH score in the PQ-sparing group was significantly lower than that in the PQ-releasing group at 1 and 2 months postoperatively. There were no significant differences, however, in the other functional parameters in the groups through the observation period. Conclusions: The PQ muscle–sparing approach appears to achieve satisfactory results in patients undergoing VLP fixation of comminuted intra-articular fractures of the distal radius. PMID:27418895

  1. Response of Composite Plates with Inclined Elliptical Notches and Subjected to Axial Compression

    NASA Technical Reports Server (NTRS)

    Ambur, Damodar R.; McGowan, David M.

    1999-01-01

    An analysis method for predicting the inplane stress states in anisotropic finite plates with an elliptical notch is presented. This method can be used to analyze plates with arbitrary notch orientations with respect to the plate material axes. The analysis results have been validated using finite element analysis results for unnotched composite plates and experimental and finite element analysis results for stiffened composite panels with a skin that has orthotropic properties. The good agreement between these results, until the panel exhibits nonlinear response either due to bending or initiation of damage, indicates that the present analysis method can be used to determine accurately the inplane stress states and stress concentrations at and around an elliptical notch.

  2. [Comparative serology in typhoid fever in children. II. Comparison of a microhemagglutination plate technic with Ruiz-Castañeda surface fixation].

    PubMed

    Alvarado-Alemán, F; González-Quijano, M; Rodríguez-Solis, B; Ramírez-Vidals, A; Isibasi, A; Kumate, J

    1989-02-01

    Two lipopolysaccharide antigens that differ by the technique of preparation from S. typhi, one named crude is easily extracted, the other one is water-phenol extracted. Both were adsorbed by papain and cysteine to lamb erythrocyte surfaces, fixed then by glutaraldehyde and used in a plate microhemagglutination test (MHA). The MHA test was done with 30 sera from children with S. typhi blood isolates. The same number of control sera were tested for comparison. The crude LPS antigen showed better sensitivity: 73% versus 53% of the water-phenol extracted one despite a high index correlation (r = 0.88). The latest one was evaluated in a prospective study, using it during a six-month period in an emergency room with S. typhi blood isolated sera. The MHA test was compared with the surface fixation test. Both assays showed similar sensitivity and a specificity of 91 and 100%, respectively.

  3. Treatment of reducible unstable fractures of the distal radius: randomized clinical study comparing the locked volar plate and external fixator methods: study protocol

    PubMed Central

    2014-01-01

    Background Various treatments are available for reducible unstable fractures of the distal radius, such as closed reduction combined with fixation by external fixator (EF), and rigid internal fixation using a locked volar plate (VP). Although there are studies comparing these methods, there is no conclusive evidence indicating which treatment is best. The hypothesis of this study is that surgical treatment with a VP is more effective than EF from the standpoint of functional outcome (patient-reported). Methods/Design The study is randomized clinical trial with parallel groups and a blinded evaluator and involves the surgical interventions EF and VP. Patients will be randomly assigned (assignment ratio 1:1) using sealed opaque envelopes. This trial will include consecutive adult patients with an acute (up to 15 days) displaced, unstable fracture of the distal end of the radius of type A2, A3, C1, C2 or C3 by the Arbeitsgemeinschaft für Osteosynthesefragen–Association for the Study of Internal Fixation classification and type II or type III by the IDEAL32 classification, without previous surgical treatments of the wrist. The surgical intervention assigned will be performed by three surgical specialists familiar with the techniques described. Evaluations will be performed at 2, and 8 weeks, 3, 6 and 12 months, with the primary outcomes being measured by the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire and measurement of pain (Visual Analog Pain Scale and digital algometer). Secondary outcomes will include radiographic parameters, objective functional evaluation (goniometry and dynamometry), and the rate of complications and method failure according to the intention-to-treat principle. Final postoperative evaluations (6 and 12 months) will be performed by independent blinded evaluators. For the Student’s t-test, a difference of 10 points in the DASH score, with a 95% confidence interval, a statistical power of 80%, and 20% sampling error

  4. The compact capacitor bank CQ-1.5 employed in magnetically driven isentropic compression and high velocity flyer plate experiments.

    PubMed

    Wang, Guiji; Sun, Chengwei; Tan, Fuli; Zhao, Jianheng; Zhang, Ning; Liu, Cangli; Mo, Jianjun; Wang, Ganghua; Wang, Xiaosong

    2008-05-01

    Based on the low inductance capacitor, the parallel-plate transmission line, and the explosive network closing switch, a compact pulsed power generator CQ-1.5 has been developed at the Institute of Fluid Physics and is capable to deliver a current of peak of 1.5 MA within rise time of 500-570 ns into a 2-3 nH inductive load. The work is motivated to do isentropic compression experiments (ICEs) on metals up to 30-50 GPa and to launch flyer plates at velocities over 8 kms. The experiments were conducted with the diagnostics of both Doppler pin system and velocity interferometer system for any reflectors, and the measured free surface velocity histories of ICE samples were treated with a backward integration code. The results show that the isentropes of Cu and Al samples under 35 GPa are close to their Hugoniots within a deviation of 3%. The LY12 aluminum flyer plates were accelerated to a velocity over 8.96 kms.

  5. Modal parameter identification of a compression-loaded CFRP stiffened plate and correlation with its buckling behaviour

    NASA Astrophysics Data System (ADS)

    Chaves-Vargas, M.; Dafnis, A.; Reimerdes, H.-G.; Schröder, K.-U.

    2015-10-01

    In order to study the dynamic response and the buckling behaviour of several load-carrying structural components of civil aircraft when subjected to transient load scenarios such as gusts or a landing impact, a generic mid-size aircraft is defined within the European research project DAEDALOS. From this aircraft, several sections or panels in different regions such as wing, vertical tailplane and fuselage are defined. The stiffened carbon-fibre-reinforced plastic (CFRP) plate investigated within the present work represents a simplified version of the wing panel selected from the generic aircraft. As part of the current work, the buckling behaviour and the modal properties of the stiffened plate under the effect of a static in-plane compression load are studied. This is accomplished by means of a test series including quasi-static buckling tests and an experimental modal analysis (EMA). One of the key objectives pursued is the correlation of the modal properties to the buckling behaviour by studying the relationship between the natural frequencies of the stiffened plate and its corresponding buckling load. The experimental work is verified by a finite element analysis.

  6. Internal (Annular) and Compressible External (Flat Plate) Turbulent Flow Heat Transfer Correlations.

    SciTech Connect

    Dechant, Lawrence; Smith, Justin

    2016-01-01

    Here we provide a discussion regarding the applicability of a family of traditional heat transfer correlation based models for several (unit level) heat transfer problems associated with flight heat transfer estimates and internal flow heat transfer associated with an experimental simulation design (Dobranich 2014). Variability between semi-empirical free-flight models suggests relative differences for heat transfer coefficients on the order of 10%, while the internal annular flow behavior is larger with differences on the order of 20%. We emphasize that these expressions are strictly valid only for the geometries they have been derived for e.g. the fully developed annular flow or simple external flow problems. Though, the application of flat plate skin friction estimate to cylindrical bodies is a traditional procedure to estimate skin friction and heat transfer, an over-prediction bias is often observed using these approximations for missile type bodies. As a correction for this over-estimate trend, we discuss a simple scaling reduction factor for flat plate turbulent skin friction and heat transfer solutions (correlations) applied to blunt bodies of revolution at zero angle of attack. The method estimates the ratio between axisymmetric and 2-d stagnation point heat transfer skin friction and Stanton number solution expressions for sub-turbulent Reynolds numbers %3C1x10 4 . This factor is assumed to also directly influence the flat plate results applied to the cylindrical portion of the flow and the flat plate correlations are modified by

  7. Damage assessment and residual compression strength of thick composite plates with through-the-thickness reinforcements

    NASA Technical Reports Server (NTRS)

    Smith, Barry T.

    1990-01-01

    Damage in composite materials was studied with through-the-thickness reinforcements. As a first step it was necessary to develop new ultrasonic imaging technology to better assess internal damage of the composite. A useful ultrasonic imaging technique was successfully developed to assess the internal damage of composite panels. The ultrasonic technique accurately determines the size of the internal damage. It was found that the ultrasonic imaging technique was better able to assess the damage in a composite panel with through-the-thickness reinforcements than by destructively sectioning the specimen and visual inspection under a microscope. Five composite compression-after-impact panels were tested. The compression-after-impact strength of the panels with the through-the-thickness reinforcements was almost twice that of the comparable panel without through-the-thickness reinforcement.

  8. Damage assessment and residual compression strength of thick composite plates with through-the-thickness reinforcements

    NASA Technical Reports Server (NTRS)

    Smith, Barry T.; Farley, Gary L.; Maiden, Janice; Coogan, Dreux; Moore, Judith G.

    1991-01-01

    Damage in composite materials was studied with through-the-thickness reinforcements. As a first step it was necessary to develop new ultrasonic imaging technology to better assess internal damage of the composite. A useful ultrasonic imaging technique was successfully developed to assess the internal damage of composite panels. The ultrasonic technique accurately determines the size of the internal damage. It was found that the ultrasonic imaging technique was better able to assess the damage in composite panel with through-the-thickness reinforcements than by destructively sectioning the specimen and visual inspection under a microscope. Five composite compression-after-impact panels were tested. The compression-after-impact strength of the panels with the through-the-thickness reinforcements was almost twice that of the comparable panel without through-the-thickness reinforcement.

  9. The plastic compressibility of 7075-T651 aluminum-alloy plate

    NASA Technical Reports Server (NTRS)

    Freed, A. D.; Sandor, B. I.

    1986-01-01

    The change in volume, and therefore the change in mass density, of an aluminum alloy was measured in uniaxial tension using clip-on extensometers. The experimental data do not agree with the assumption of plastic incompressibility found in the classical theories of plasticity. In fact, the elastic and plastic volume changes are of the same order of magnitude. Plastic anisotropy is thought to be the prime cause of this plastic compressibility.

  10. The compressive failure of graphite/epoxy plates with circular holes

    NASA Technical Reports Server (NTRS)

    Knauss, J. F.; Starnes, J. H., Jr.; Henneke, E. G., II

    1978-01-01

    The behavior of fiber reinforced composite plates containing a circular cutout was characterized in terms of geometry (thickness, width, hole diameter), and material properties (bending/extensional stiffness). Results were incorporated in a data base for use by designers in determining the ultimate strength of such a structure. Two thicknesses, 24 plies and 48 plies were chosen to differentiate between buckling and strength failures due to the presence of a cutout. Consistent post-buckling strength was exhibited by both laminate configurations.

  11. EVALUATION OF PATIENTS UNDERGOING FIXATION OF DIAPHYSEAL HUMERAL FRACTURES USING THE MINIMALLY INVASIVE BRIDGE-PLATE TECHNIQUE

    PubMed Central

    Superti, Mauro José; Martynetz, Fábio; Falavinha, Ricardo Sprenger; Fávaro, Rodrigo Caldonazzo; Boas, Luis Felipe Villas; Filho, Salim Mussi; Martynetz, Juliano; Ribas, Bruno

    2015-01-01

    Objective: The aim was to describe the experience of our group in treating humeral shaft fractures using the bridge–plate technique via an anterior approach. Methods: Seventeen patients with acute diaphyseal humeral fractures with an indication for surgical treatment who were operated in 2006–2010 were evaluated. The AO and Gustilo & Anderson classifications were used. All the patients were operated using the anterior bridge-plate technique and completed a follow–up period of at least twelve months. Results: Sixteen men and one woman were treated. Their mean age was 31.8 years (18–52). Among the injury mechanisms found were: five motorcycle accidents, four car accidents, three fractures due to firearm projectiles, two falls to the ground and finally, with one case each, assault, crushing and being run over. Eight patients had open fractures: two grade I, one grade II, four grade IIIa and one grade IIIb, according to the Gustilo-Anderson classification. In relation to the AO classification, we found: one 12A1, three 12A2, four 12A3, one 12B1, four 12 B2, three 12B3 and one 12C2. The mean postoperative follow-up was 25 months (12–48). As complications, two patients had pain in the elbow and a ROM deficit and one had deep infection. The mean time taken to achieve consolidation was 17.5 weeks. There was no loss of reduction, pseudarthrosis or malunion in this series of patients. Conclusion: The authors believe that the technique described has low rates of complications and morbidity, with good initial results, although the series is limited by the small sample. PMID:27042639

  12. Investigation of crystallinity, molecular weight change, and mechanical properties of PLA/PBG bioresorbable composites as bone fracture fixation plates.

    PubMed

    Felfel, Reda M; Ahmed, Ifty; Parsons, Andrew J; Haque, Papia; Walker, Gavin S; Rudd, Chris D

    2012-03-01

    In this study, bioresorbable phosphate-based glass (PBG) fibers were used to reinforce poly(lactic acid) (PLA). PLA/PBG random mat (RM) and unidirectional (UD) composites were prepared via laminate stacking and compression molding with fiber volume fractions between 14% and 18%, respectively. The percentage of water uptake and mass change for UD composites were higher than the RM composites and unreinforced PLA. The crystallinity of the unreinforced PLA and composites increased during the first few weeks and then a plateau was seen. XRD analysis detected a crystalline peak at 16.6° in the unreinforced PLA sample after 42 days of immersion in phosphate buffer solution (PBS) at 37°C. The initial flexural strength of RM and UD composites was ∼106 and ∼115 MPa, whilst the modulus was ∼6.7 and ∼9 GPa, respectively. After 95 days immersion in PBS at 37°C, the strength decreased to 48 and 52 MPa, respectively as a result of fiber-matrix interface degradation. There was no significant change in flexural modulus for the UD composites, whilst the RM composites saw a decrease of ∼45%. The molecular weight of PLA alone, RM, and UD composites decreased linearly with time during degradation due to chain scission of the matrix. Short fiber pull-out was seen from SEM micrographs for both RM and UD composites.

  13. Comparative Analysis of Interbody Cages Versus Tricortical Graft with Anterior Plate Fixation for Anterior Cervical Discectomy and Fusion in Degenerative Cervical Disc Disease

    PubMed Central

    Singh, Pritish; Shekhawat, Vishal

    2016-01-01

    Introduction Multiple techniques and modalities of fixation are used in Anterior Cervical Discectomy and interbody Fusion (ACDF), each with some merit and demerit against others. Such pool of techniques reflects lack of a consensus method conducive to uniformly good results. Aim A prospective study was done to analyse safety and efficacy of tricortical autograft and anterior cervical plate (Group A) with cylindrical titanium cage filled with cancellous bone (Group B) in procedure of ACDF for single level degenerative cervical disc disease. Materials and Methods Twenty patients with degenerative cervical disc disease were included in study for ACDF. After a computer generated randomisation, ten patients (10 segments) were operated with anterior locking plating and tricortical iliac crest graft (Group A, Tricortical graft group), while ten patients(10 segments) were operated with standalone cylindrical titanium cages filled with cancellous bone harvested using minimally invasive methods (Group B, Cage group) from April 2012 to May 2015. Odoms’s criteria, visual pain analogue score and sequential plain radiographs were obtained to assess for clinic-radiological outcome. Results According to Odom’s system of functional assessment, 9 patients from each group (90%) experienced good to excellent functional recovery and 9 of 10 (90%) patients of each groups were satisfied with outcome. In both groups, relief in neck pain or arm pain was similar without any statistical difference as assessed by visual analogue score. Fusion was present in 10 of 10 (100%) patients in tricortical graft group and 10 of 10 (100%) in cage group at the end of 6 months. There was no implant related complications in cage group. Transient postoperative dysphagia was recorded in 3 patients (2 in Group A and 1 in group B), which resolved within 3 days. In tricortical graft group, graft collapse and partial extrusion was detected in one patient, which did not correspond with good results obtained

  14. Is a single anterolateral screw-plate fixation sufficient for the treatment of spinal fractures in the thoracolumbar junction? A biomechanical in vitro investigation.

    PubMed

    Schreiber, Ulrich; Bence, Tibor; Grupp, Thomas; Steinhauser, Erwin; Mückley, Thomas; Mittelmeier, Wolfram; Beisse, Rudolf

    2005-03-01

    Controversy exists about the indications, advantages and disadvantages of various surgical techniques used for anterior interbody fusion of spinal fractures in the thoracolumbar junction. The purpose of this study was to evaluate the stabilizing effect of an anterolateral and thoracoscopically implantable screw-plate system. Six human bisegmental spinal units (T12-L2) were used for the biomechanical in vitro testing procedure. Each specimen was tested in three different scenarios: (1) intact spinal segments vs (2) monosegmental (T12/L1) anterolateral fixation (macsTL, Aesculap, Germany) with an interbody bone strut graft from the iliac crest after both partial corpectomy (L1) and discectomy (T12/L1) vs (3) bisegmental anterolateral instrumentation after extended partial corpectomy (L1), and bisegmental discectomy (T12/L1 and L1/L2). Specimens were loaded with an alternating, nondestructive maximum bending moment of +/-7.5 Nm in six directions: flexion/extension, right and left lateral bending, and right and left axial rotation. Motion analysis was performed by a contact-less three-dimensional optical measuring system. Segmental stiffness of the three different scenarios was evaluated by the relative alteration of the intervertebral angles in the three main anatomical planes. With each stabilization technique, the specimens were more rigid, compared with the intact spine, for flexion/extension (sagittal plane) as well as in left and right lateral bending (frontal plane). In these planes the bisegmental instrumentation compared to the monosegmental case had an even larger stiffening effect on the specimens. In contrast to these findings, axial rotation showed a modest increase of motion after bisegmental instrumentation. To conclude, the immobilization of monosegmental fractures in the thoracolumbar junction can be secured by means of bone grafting and the implant used in this study for all three anatomical planes. After bisegmental anterolateral stabilization a

  15. Effect of shell drilling stiffness on response calculations of rectangular plates and tubes of rectangular cross-section under compression.

    SciTech Connect

    Gorman, Jhana; Hales, Jason Dean; Corona, Edmundo

    2010-05-01

    This report considers the calculation of the quasi-static nonlinear response of rectangular flat plates and tubes of rectangular cross-section subjected to compressive loads using quadrilateralshell finite element models. The principal objective is to assess the effect that the shell drilling stiffness parameter has on the calculated results. The calculated collapse load of elastic-plastic tubes of rectangular cross-section is of particular interest here. The drilling stiffness factor specifies the amount of artificial stiffness that is given to the shell element drilling Degree of freedom (rotation normal to the plane of the element). The element formulation has no stiffness for this degree of freedom, and this can lead to numerical difficulties. The results indicate that in the problems considered it is necessary to add a small amount of drilling tiffness to obtain converged results when using both implicit quasi-statics or explicit dynamics methods. The report concludes with a parametric study of the imperfection sensitivity of the calculated responses of the elastic-plastic tubes with rectangular cross-section.

  16. Elbow Reconstruction With Compression Plate Arthrodesis and Circumferential Muscle-Sparing Latissimus Dorsi Flap After Tumor Resection

    PubMed Central

    Ng, Zhi Yang; Ramachandran, Savitha; Tan, Bien-Keem; Foo, Leon; Ng, Siew-Weng

    2016-01-01

    Background: The goals of limb-sparing surgery in the setting of extremity malignancies are 2-fold: oncological clearance and the rehabilitation of function and aesthetics. Treatment success should be defined by the extent of restoration of the patient’s premorbid function for reintegration into society. Methods: We would like to report an unusual case of a patient with a chronically ankylosed elbow with joint invasion by basal cell carcinoma which resulted from malignant transformation of an overlying, long-standing wound due to inadequately treated septic arthritis from his childhood years. Results: Following R0 resection, upper limb shortening and compression plate elbow arthrodesis were performed with the aim of restoring the degree of upper limb function that the patient had been accustomed to preoperatively. The resultant circumferential defect was then closed with a contralateral, free muscle-sparing latissimus dorsi flap. Conclusions: Functional preservation may therefore be more important than the mere restoration of anatomical defects in these especially challenging situations. PMID:27418897

  17. 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.

  18. Percutaneous Screw Fixation of Crescent Fracture-Dislocation of the Sacroiliac Joint.

    PubMed

    Shui, Xiaolong; Ying, Xiaozhou; Mao, Chuanwan; Feng, Yongzeng; Chen, Linwei; Kong, Jianzhong; Guo, Xiaoshan; Wang, Gang

    2015-11-01

    Crescent fracture-dislocation of the sacroiliac joint (CFDSIJ) is a type of lateral compression pelvic injury associated with instability. Open reduction and internal fixation is a traditional treatment of CFDSIJ. However, a minimally invasive method has never been reported. The purpose of this study was to assess the outcome of closed reduction and percutaneous fixation for different types of CFDSIJ and present their clinical outcome. The authors reviewed 117 patients diagnosed with CFDSIJ between July 2003 and July 2013. Closed reduction and percutaneous fixation was performed in 73 patients. Treatment selection was based on Day's fracture classification. For type I fractures, fixation perpendicular to the fracture line were performed. For type II fractures, crossed fixation was performed. For type III fractures, fixation was performed with iliosacral screws. Forty-four patients were treated by open reduction and plate fixation. Demographics, fracture pattern distribution, blood loss, incision lengths, revision surgeries, radiological results, and functional scores were compared. All 117 patients were followed for more than 6 months (mean, 14 months [range, 6-24 months]). Blood loss, extensive exposure, duration of posterior ring surgery, duration of hospital stay, and infection rates were lower in the closed group (P<.01). Patients in the closed group achieved better functional performance (P<.01). There were no significant differences in reduction quality (P=.32), revision surgery rates (P=.27), and iatrogenic neurologic injuries (P=.2) between the 2 groups. The authors' results indicate that closed reduction and percutaneous fixation is a safe and effective surgical method for CFDSIJ.

  19. Locking versus Non-locking Neutralization Plates with Limited Excision and Internal Fixation for Treatment of Extra-articular Type a Distal Tibial Fractures

    PubMed Central

    Zhou, Kai-hua; Chen, Nong

    2017-01-01

    Purpose: This study aimed to compare the clinical, radiologic, and cost-effectiveness results between locking and non-locking plates for the treatment of extra-articular type A distal tibial fractures. Methods: We performed a retrospective review of AO/OTA 42-A1, A2 distal tibial fractures treated by plates from January 2011 to June 2013. Patients were divided to the locking plate group or the non-locking plate group. Clinical outcomes, radiographic outcomes, and hospitalization fee were compared between the two plates groups. Results: 28 patients were treated with a locking plate and 23 patients were treated with a non-locking plate. The mean follow-up was 18.8 months (12-23 months). There were no significant differences between the groups in surgical time, bleeding, bone union time, or AOFAS scores. The cost of the locking plate was ¥24,648.41 ± 6,812.95 and the cost of the non-locking plate was ¥11,642 ± 3,162.57, p < 0.001. Each group had one patient that experienced superficial infection these wounds were readily healed by oral antibiotics and dressing changes. To date, five patients in the locking group and ten patients in the non-locking group had sensations of metal stimulation or other discomfort (X2 = 3.99, p < 0.05) Until the last follow-up, 14 patients in the locking plate group and 18 patients in the non-locking plate group had their plates removed or wanted to remove their plates (X2 = 4.31, p < 0.05). Conclusion: The use of locking or non-locking plates provides a similar outcome in the treatment of distal fractures. However the locking plate is much more expensive than the non-locking plate.

  20. On the stability of a plate under longitudinal compression on a two-layer half-space with lower layer prestressed by gravity forces

    NASA Astrophysics Data System (ADS)

    Alexandrov, V. M.; Zarubov, D. I.

    2008-06-01

    In the plane (plane strain) and axially symmetric statements, we study the problem of stability, under the action of longitudinal compressing forces, of an infinite elastic plate in two-sided contact with an elastic half-space. The upper layer of finite depth is described by the usual equations of linear theory of elasticity; the lower layer, which is geometrically nonlinear, incompressible, and infinite in depth, is prestressed by gravity forces. The total adhesion between the layer of finite depth and the lower half-space is realized. It is also assumed that the same adhesion takes place between the upper layer of the half-space and the plate with the contact tangential stresses taken into account. The results can be used to calculate the working capacity of coated bodies and layered composites and in problems of geophysics. The problem of stability of an infinite elastic plate under longitudinal compression under conditions of two-sided contact with an elastic base was studied earlier in the monograph [1] (Fuss-Winkler base) and in [2-4].

  1. Titanium Elastic Nail (TEN) versus Reconstruction Plate Repair of Midshaft Clavicular Fractures: A Finite Element Study

    PubMed Central

    Liu, Yanjie; Zhang, Wen; Pan, Yao; Zhang, Wei; Zhang, Changqing; Zeng, Bingfang; Chen, Yunfeng

    2015-01-01

    Background The biomechanical characteristics of midshaft clavicular fractures treated with titanium elastic nail (TEN) is unclear. This study aimed to present a biomechanical finite element analysis of biomechanical characteristics involved in TEN fixation and reconstruction plate fixation for midshaft clavicular fractures. Methods Finite element models of the intact clavicle and of midshaft clavicular fractures fixed with TEN and with a reconstruction plate were built. The distal clavicle displacement, peak stress, and stress distribution on the 3 finite element models were calculated under the axial compression and cantilever bending. Results In both loading configurations, TEN generated the highest displacement of the distal clavicle, followed by the intact clavicle and the reconstruction plate. TEN showed higher peak bone and implant stresses, and is more likely to fail in both loading configurations compared with the reconstruction plate. TEN led to a stress distribution similar to that of the intact clavicle in both loading configurations, whereas the stress distribution with the reconstruction plate was nonphysiological in cantilever bending. Conclusions TEN is generally preferable for treating simple displaced fractures of the midshaft clavicle, because it showed a stress distribution similar to the intact clavicle. However, TEN provides less stability, and excessive exercise of and weight bearing on the ipsilateral shoulder should be avoided in the early postoperative period. Fixation with a reconstruction plate was more stable but showed obvious stress shielding. Therefore, for patients with a demand for early return to activity, reconstruction plate fixation may be preferred. PMID:25965409

  2. Open reduction and internal fixation of OTA type C2-C4 fractures of the calcaneus with a triple-plate technique.

    PubMed

    Brunner, Alexander; Müller, Jochen; Regazzoni, Pietro; Babst, Reto

    2012-01-01

    The purpose of this study was to present a surgical technique of open reduction and internal fixation of displaced intra-articular calcaneal fractures with 3 AO mini-fragment plates and to evaluate the clinical and radiological outcome of a consecutive group of patients after a mean follow-up of 41.7 months. A series of 54 patients (16 women and 38 men) with 62 calcaneal fractures were treated over a period of 6.5 years. Forty-five patients with 50 calcaneal fractures were completely clinically and radiologically followed up. Clinical follow-up included assessment of range of motion, pain according to a visual analogue scale, the American Orthopaedic Foot and Ankle Society hindfoot score, and the short-form 36 health survey. Radiological follow-up included plain axial and lateral radiographs and measurement of the Böhler's angle and Gissane's angle. Independent Student's t test and paired Student's t test were used alongside the chi-square test to compare clinical and radiological data and score values between different groups of patients. Eleven patients showed breakage of the osteosynthesis material during the healing process and 2 patients sustained deep wound infection requiring revision surgery. At the final follow-up all fractures had healed. The average range of motion was supination 26.4° (range 0° to 50°; SD 11.6°), pronation 15.4° (range 0° to 30°; SD 6.4°), dorsal extension 14.3° (range -10° to 30°; SD 8.0°), and plantarflexion 39.6° (range 20° to 65°; SD 11.7°). Patients with OTA type C4 fractures achieved significantly lower supination (p < .01) and plantarflexion (p < .01) compared with other fracture types. The mean visual analog scale pain score was 3.6 (range 0 to 8; SD 2.3) points, average American Orthopaedic Foot and Ankle Society hindfoot score was 70.8 (range 33 to 100; SD 17.1) points, and the mean short-form 36 score was 60.98 (range 22.9 to 93.0; SD 18.4) points. The mean postoperative Böhler's angle was 28.9° (range 8

  3. Swan-like Memory Compressive Connector

    NASA Astrophysics Data System (ADS)

    Xu, Shuo-Gui; Zhang, Chun-Cai; Wu, Ya-Le; Fu, Qing-Ge

    2011-02-01

    Nonunion is a common complication after fractures of the diaphysis of the upper extremity. Conventional internal fixation cannot provide compressive stress at the fracture site, which is critical for fracture repair in nonweight-bearing bones. In order to overcome this problem, we developed a novel nitinol device that provides initial and continuous compression and three dimensional fixation, the swan-like memory compressive connector (SMC). A total of 188 cases (243 bones) of fractures and nonunions were treated by SMC over the course of 16 years. At follow-up, the nonunion sites were bridged by plate-like bone in 92 cases (106 bones) at an average of 3.8 months after surgery. In the fracture group, the fracture sites were bridged by plate-like bone in 93 cases (134 bones) at an average of 2.6 months after surgery. No infection or re-fracture occurred after removal of the SMC. There was no persistent joint dysfunction caused by the SMC.

  4. Ultrasonometry evaluation of axial compression osteosinthesis. An experimental study

    PubMed Central

    Bezuti, Márcio Takey; Mandarano, Luiz Garcia; Barbieri, Giuliano; Mazzer, Nilton; Barbieri, Cláudio Henrique

    2013-01-01

    OBJECTIVE: To measure the ultrasound propagation velocity (UV) through a tibial transverse osteotomy in sheep, before and after the fixation with a DCP plate. MATERIAL AND METHODS: Ten assemblies of a DCP plate with the diaphyseal segment of tibiae, in which a transverse osteotomy was made, were used. Both coronal and sagittal transverse and the axial UV were measured, first with the intact bone assembled with the plate and then with the uncompressed and compressed osteotomy; statistical comparisons were made at the 1% (p<0.01) level of significance. RESULTS: Compared with the intact bone assembly, axial UV significantly decreased with the addition of the osteotomy and significantly increased with compression, presenting the same behavior for the other modalities, although not significantly. DISCUSSION AND CONCLUSION: In accordance with the literature data on the ultrasonometric evaluation of fracture healing, underwater UV measurement was able to demonstrate the efficiency of DCP plate fixation. The authors conclude that the method has a potential for clinical application in the postoperative follow-up of DCP plate osteosinthesis, with a capability to demonstrate when it becomes ineffective. Laboratory investigation. PMID:24453644

  5. Dynamic hip screw versus proximal femur locking compression plate in intertrochanteric femur fractures (AO 31A1 and 31A2): A prospective randomized study

    PubMed Central

    Agrawal, Prabhat; Gaba, Sahil; Das, Saubhik; Singh, Ranjit; Kumar, Arvind; Yadav, Gajanand

    2017-01-01

    Introduction: Intertrochanteric fractures are common in elderly population and pose a significant financial burden to the society. Anatomically contoured proximal femur locking compression plate (PFLCP) is the latest addition in the surgeons’ armamentarium to deal with these fractures. It creates an angular stable construct, which will theoretically lessen the risk of failure by screw cut-out and varus collapse, the common mode of DHS failure. We compared DHS with PFLCP in AO type 31A1 and 31A2 intertrochanteric fractures. Materials and Methods: A randomized prospective study was carried out between June 2011 and June 2013. 26 cases each of DHS and PFLCP were included. Results: Functional and radiological outcome was similar in both groups. Conclusion: Both DHS and PFLCP are good choices for stable intertrochanteric fractures, and both lead to excellent functional outcomes, but non-union might be more common with PFLCP.

  6. Analysis of residual stress and hardness in regions of pre-manufactured and manual bends in fixation plates for maxillary advancement.

    PubMed

    Araújo, Marcelo Marotta; Lauria, Andrezza; Mendes, Marcelo Breno Meneses; Claro, Ana Paula Rosifini Alves; Claro, Cristiane Aparecida de Assis; Moreira, Roger William Fernandes

    2015-12-01

    The aim of this study was to analyze, through Vickers hardness test and photoelasticity analysis, pre-bent areas, manually bent areas, and areas without bends of 10-mm advancement pre-bent titanium plates (Leibinger system). The work was divided into three groups: group I-region without bend, group II-region of 90° manual bend, and group III-region of 90° pre-fabricated bends. All the materials were evaluated through hardness analysis by the Vickers hardness test, stress analysis by residual images obtained in a polariscope, and photoelastic analysis by reflection during the manual bending. The data obtained from the hardness tests were statistically analyzed using ANOVA and Tukey's tests at a significance level of 5 %. The pre-bent plate (group III) showed hardness means statistically significantly higher (P < 0.05) than those of the other groups (I-region without bends, II-90° manually bent region). Through the study of photoelastic reflection, it was possible to identify that the stress gradually increased, reaching a pink color (1.81 δ / λ), as the bending was performed. A general analysis of the results showed that the bent plate region of pre-bent titanium presented the best results.

  7. Computational modelling of long bone fractures fixed with locking plates – How can the risk of implant failure be reduced?

    PubMed Central

    Nassiri, M.; MacDonald, B.; O'Byrne, J.M.

    2013-01-01

    Background and purpose The Locking Compression Plate (LCP) is part of a new plate generation requiring an adapted surgical technique and new thinking about commonly used concepts of internal fixation using plates. Knowledge of the fixation stability provided by these new plates is very limited and clarification is still necessary to determine how the mechanical stability and the risk of implant failure can best be controlled. Methods Upon validation, a finite element model of an LCP attached to a cylinder was developed to simulate and analyse the biomechanics of a transverse long bone fracture fixed with a locking plate. Of special interest were the factors influencing the mechanical conditions at the fracture site, the control of interfragmentary movement and implant failure. Results Several factors were shown to influence stability in compression. Increasing translation and/or fracture angle post fixation reduced construct stability. Axial stiffness was also influenced by the working length and plate-bone distance. The fracture gap had no effect on the construct stability when no bone contact occurred during loading. Stress analysis of the LCP demonstrated that the maximum Von Mises stresses were found in the innermost screws at the screw-head junction. Interpretation For the clinical use of the LCP as a locked internal fixator in fractures with an interfragmentary gap of 1 mm, at least two to four plate holes near the fracture gap should be omitted to allow fracture motion and bone contact to occur. This will also achieve a larger area of stress distribution on the plate and reduce the likelihood of fatigue failure due to cyclic loading. PMID:24403745

  8. Laser-driven flyer plates for shock compression science: Launch and target impact probed by photon Doppler velocimetry

    NASA Astrophysics Data System (ADS)

    Curtis, Alexander D.; Banishev, Alexandr A.; Shaw, William L.; Dlott, Dana D.

    2014-04-01

    We investigated the launch and target impact of laser-driven Al flyer plates using photon Doppler velocimetry (PDV). We studied different flyer designs launched by laser pulses of different energies, pulse durations and beam diameters, that produced km s-1 impacts with transparent target materials. Laser-launching Al flyers 25-100 μm thick cemented to glass substrates is usually thought to involve laser vaporization of a portion of the flyer, which creates many difficulties associated with loss of integrity and heating of the flyer material. However, in the system used here, the launch mechanism was surprising and unexpected: it involved optical damage at the glass/cement/flyer interface, with very little laser light reaching the flyer itself. In fact the flyers launched in this manner behaved almost identically to multilayer flyers that were optically shielded from the laser pulses and insulated from heat generated by the pulses. Launching flyers with nanosecond laser pulses creates undesirable reverberating shocks in the flyer. In some cases, with 10 ns launch pulses, the thickest flyers were observed to lose integrity. But with stretched 20 ns pulses, we showed that the reverberations damped out prior to impact with targets, and that the flyers maintained their integrity during flight. Flyer impacts with salt, glass, fused silica, and acrylic polymer were studied by PDV, and the durations of fully supported shocks in those media were determined, and could be varied from 5 to 23 ns.

  9. Laser-driven flyer plates for shock compression science: launch and target impact probed by photon Doppler velocimetry.

    PubMed

    Curtis, Alexander D; Banishev, Alexandr A; Shaw, William L; Dlott, Dana D

    2014-04-01

    We investigated the launch and target impact of laser-driven Al flyer plates using photon Doppler velocimetry (PDV). We studied different flyer designs launched by laser pulses of different energies, pulse durations and beam diameters, that produced km s(-1) impacts with transparent target materials. Laser-launching Al flyers 25-100 μm thick cemented to glass substrates is usually thought to involve laser vaporization of a portion of the flyer, which creates many difficulties associated with loss of integrity and heating of the flyer material. However, in the system used here, the launch mechanism was surprising and unexpected: it involved optical damage at the glass/cement/flyer interface, with very little laser light reaching the flyer itself. In fact the flyers launched in this manner behaved almost identically to multilayer flyers that were optically shielded from the laser pulses and insulated from heat generated by the pulses. Launching flyers with nanosecond laser pulses creates undesirable reverberating shocks in the flyer. In some cases, with 10 ns launch pulses, the thickest flyers were observed to lose integrity. But with stretched 20 ns pulses, we showed that the reverberations damped out prior to impact with targets, and that the flyers maintained their integrity during flight. Flyer impacts with salt, glass, fused silica, and acrylic polymer were studied by PDV, and the durations of fully supported shocks in those media were determined, and could be varied from 5 to 23 ns.

  10. Laser-driven flyer plates for shock compression science: Launch and target impact probed by photon Doppler velocimetry

    SciTech Connect

    Curtis, Alexander D.; Banishev, Alexandr A.; Shaw, William L.; Dlott, Dana D.

    2014-04-15

    We investigated the launch and target impact of laser-driven Al flyer plates using photon Doppler velocimetry (PDV). We studied different flyer designs launched by laser pulses of different energies, pulse durations and beam diameters, that produced km s{sup −1} impacts with transparent target materials. Laser-launching Al flyers 25–100 μm thick cemented to glass substrates is usually thought to involve laser vaporization of a portion of the flyer, which creates many difficulties associated with loss of integrity and heating of the flyer material. However, in the system used here, the launch mechanism was surprising and unexpected: it involved optical damage at the glass/cement/flyer interface, with very little laser light reaching the flyer itself. In fact the flyers launched in this manner behaved almost identically to multilayer flyers that were optically shielded from the laser pulses and insulated from heat generated by the pulses. Launching flyers with nanosecond laser pulses creates undesirable reverberating shocks in the flyer. In some cases, with 10 ns launch pulses, the thickest flyers were observed to lose integrity. But with stretched 20 ns pulses, we showed that the reverberations damped out prior to impact with targets, and that the flyers maintained their integrity during flight. Flyer impacts with salt, glass, fused silica, and acrylic polymer were studied by PDV, and the durations of fully supported shocks in those media were determined, and could be varied from 5 to 23 ns.

  11. Open reduction and temporary internal fixation of a subacute elbow dislocation.

    PubMed

    Neuhaus, Valentin; Alqueza, Arnold; Mudgal, Chaitanya S

    2012-05-01

    We present the case of a 61-year-old woman with a subacute elbow dislocation, who was referred to our institution 4 weeks after a fall. She was treated with open reduction and temporary bridging internal fixation through a posterior approach with a limited contact dynamic compression plate. After 4 weeks, the hardware was removed. One year postoperatively, the patient had nearly pain-free motion of 20° short of full extension and full flexion. Her radiographs showed residual incongruity and degenerative arthritis of the elbow.

  12. Fixation of a Periprosthetic Intertrochanteric Hip Fracture below a Birmingham Hip Resurfacing

    PubMed Central

    Macdonald, J.; Robinson, A.; Brown, I.

    2014-01-01

    This case report involves a 56-year-old female (Mrs X) with a traumatic intertrochanteric hip fracture with subtrochanteric extension below a previous Birmingham hip resurfacing. Periprosthetic fractures following hip resurfacing are usually subcapital and treated with a revision or conservative management. We present an unusual surgical problem with an interesting solution stabilising the fracture using a proximal femoral locking compression plate (LCP). Eight months following surgery the patient is able to walk pain free and there is good fixation and stability. PMID:24995142

  13. Biomechanical Performance of Variable and Fixed Angle Locked Volar Plates for the Dorsally Comminuted Distal Radius

    PubMed Central

    Martineau, D; Shorez, J; Beran, C; Dass, A G; Atkinson, P

    2014-01-01

    Background The ideal treatment strategy for the dorsally comminuted distal radius fracture continues to evolve. Newer plate designs allow for variable axis screw placement while maintaining the advantages of locked technology. The purpose of this study is to compare the biomechanical properties of one variable axis plate with two traditional locked constructs. Methods Simulated fractures were created via a distal 1 cm dorsal wedge osteotomy in radius bone analogs. The analogs were of low stiffness and rigidity to create a worst-case strength condition for the subject radius plates. This fracture-gap model was fixated using one of three different locked volar distal radius plates: a variable axis plate (Stryker VariAx) or fixed axis (DePuy DVR, Smith & Nephew Peri-Loc) designs. The constructs were then tested at physiologic loading levels in axial compression and bending (dorsal and volar) modes. Construct stiffness was assessed by fracture gap motion during the different loading conditions. As a within-study control, intact bone analogs were similarly tested. Results All plated constructs were significantly less stiff than the intact control bone models in all loading modes (p<0.040). Amongst the plated constructs, the VariAx was stiffest axially (p=0.032) and the Peri-Loc was stiffest in bending (p<0.024). Conclusion In this analog bone fracture gap model, the variable axis locking technology was stiffer in axial compression than other plates, though less stiff in bending. PMID:25328471

  14. Latarjet Fixation

    PubMed Central

    Alvi, Hasham M.; Monroe, Emily J.; Muriuki, Muturi; Verma, Rajat N.; Marra, Guido; Saltzman, Matthew D.

    2016-01-01

    Background: Attritional bone loss in patients with recurrent anterior instability has successfully been treated with a bone block procedure such as the Latarjet. It has not been previously demonstrated whether cortical or cancellous screws are superior when used for this procedure. Purpose: To assess the strength of stainless steel cortical screws versus stainless steel cannulated cancellous screws in the Latarjet procedure. Study Design: Controlled laboratory study. Methods: Ten fresh-frozen matched-pair shoulder specimens were randomized into 2 separate fixation groups: (1) 3.5-mm stainless steel cortical screws and (2) 4.0-mm stainless steel partially threaded cannulated cancellous screws. Shoulder specimens were dissected free of all soft tissue and a 25% glenoid defect was created. The coracoid process was osteomized, placed at the site of the glenoid defect, and fixed in place with 2 parallel screws. Results: All 10 specimens failed by screw cutout. Nine of 10 specimens failed by progressive displacement with an increased number of cycles. One specimen in the 4.0-mm screw group failed by catastrophic failure on initiation of the testing protocol. The 3.5-mm screws had a mean of 274 cycles (SD, ±171 cycles; range, 10-443 cycles) to failure. The 4.0-mm screws had a mean of 135 cycles (SD, ±141 cycles; range, 0-284 cycles) to failure. There was no statistically significant difference between the 2 types of screws for cycles required to cause failure (P = .144). Conclusion: There was no statistically significant difference in energy or cycles to failure when comparing the stainless steel cortical screws versus partially threaded cannulated cancellous screws. Clinical Relevance: Latarjet may be performed using cortical or cancellous screws without a clear advantage of either option. PMID:27158630

  15. Retrospective Comparison of Percutaneous Fixation and Volar Internal Fixation of Distal Radius Fractures

    PubMed Central

    Lozano-Calderón, Santiago A.; Doornberg, Job N.

    2007-01-01

    A change in the practice of a single surgeon provided an opportunity for retrospective comparison of comparable cohorts treated with percutaneous fixation (17 patients) or a volar plate and screws (23 patients) an average of 30 months after surgery. The final evaluation was performed according to the Gartland and Werley and Mayo rating systems and the DASH questionnaire. There were no significant differences on the average scores for the percutaneous and volar plating groups, respectively: Gartland and Werley, 4 vs 5; Mayo, 82 vs 83; and DASH score 13 for both cohorts. Motion, grip, and radiographical parameters were likewise comparable. Volar internal plate and screw fixation can achieve results comparable to percutaneous fixation techniques in the treatment of fractures of the distal radius. PMID:18780085

  16. Thermal conductivity of a graphite bipolar plate (BPP) and its thermal contact resistance with fuel cell gas diffusion layers: Effect of compression, PTFE, micro porous layer (MPL), BPP out-of-flatness and cyclic load

    NASA Astrophysics Data System (ADS)

    Sadeghifar, Hamidreza; Djilali, Ned; Bahrami, Majid

    2015-01-01

    This paper reports on measurements of thermal conductivity of a graphite bipolar plate (BPP) as a function of temperature and its thermal contact resistance (TCR) with treated and untreated gas diffusion layers (GDLs). The thermal conductivity of the BPP decreases with temperature and its thermal contact resistance with GDLs, which has been overlooked in the literature, is found to be dominant over a relatively wide range of compression. The effects of PTFE loading, micro porous layer (MPL), compression, and BPP out-of-flatness are also investigated experimentally. It is found that high PTFE loadings, MPL and even small BPP out-of-flatness increase the BPP-GDL thermal contact resistance dramatically. The paper also presents the effect of cyclic load on the total resistance of a GDL-BPP assembly, which sheds light on the behavior of these materials under operating conditions in polymer electrolyte membrane fuel cells.

  17. Unstable Distal Radius Fractures Treated by Volar Locking Anatomical Plates

    PubMed Central

    Jose, Anto; Deniese, Pascal Noel; Babu, Abey Thomas; Rengasamy, Kanagasabai; Najimudeen, Syed

    2017-01-01

    Introduction Fracture of the distal end of radius represents the most common fracture of the upper extremity accounting for 16-20% of all fractures. Plating is now emerging as the gold standard for management of distal radius fractures due to increased rate of complications such as malunion, subluxation/dislocation of distal radio-ulnar joint or late collapse of fracture. Procedures such as closed reduction and cast immobilization, ligamentotaxis with external fixator and percutaneous pin fixation are no longer acceptable. Aim The purpose of the study was to evaluate the functional and radiological outcome of unstable distal radius fractures treated with the volar locking plate. Materials and Methods We reviewed 53 patients from January 2011 to December 2015, treated for unstable distal radius fractures using a volar locking compression plate. Standard radiographic and clinical assessment after 12 months (range 12-16 months) were measured and final functional and radiological outcome were assessed using the Modified Mayo wrist scoring system and Sarmiento’s modification of Lindstorm criteria respectively. Results There were 42 males and 11 females with an average age of 39.12±31.78 years (18-71 years). At the end of 12 months, 36 patients had an excellent radiological outcome and 10 patients had good radiological outcome as per Sarmiento’s modification of Lindstorm criteria. Eleven patients had an excellent functional outcome and 26 patients had a good functional outcome as per modified Mayo wrist scoring system. There was one case of superficial wound infection which subsided with intravenous antibiotics. Conclusion The volar locking plate fixation helps in early mobilization of the wrist, restores anatomy, allows early return to function, prevents secondary loss of reduction and hence is an effective treatment for unstable fractures of the distal radius. PMID:28274009

  18. Biomechanical Analysis of the Fixation System for T-Shaped Acetabular Fracture

    PubMed Central

    Fan, Yanping; Lei, Jianyin; Zhu, Feng; Li, Zhiqiang; Chen, Weiyi; Liu, Ximing

    2015-01-01

    This study aims to evaluate the biomechanical mechanism of fixation systems in the most frequent T-shaped acetabular fracture using finite element method. The treatment of acetabular fractures was based on extensive clinical experience. Three commonly accepted rigid fixation methods (double column reconstruction plates (P × 2), anterior column plate combined with posterior column screws (P + PS), and anterior column plate combined with quadrilateral area screws (P + QS)) were chosen for evaluation. On the basis of the finite element model, the biomechanics of these fixation systems were assessed through effective stiffness levels, stress distributions, force transfers, and displacements along the fracture lines. All three fixation systems can be used to obtain effective functional outcomes. The third fixation system (P + QS) was the optimal method for T-shaped acetabular fracture. This fixation system may reduce many of the risks and limitations associated with other fixation systems. PMID:26495030

  19. On optimization of a composite bone plate using the selective stress shielding approach.

    PubMed

    Samiezadeh, Saeid; Tavakkoli Avval, Pouria; Fawaz, Zouheir; Bougherara, Habiba

    2015-02-01

    Bone fracture plates are used to stabilize fractures while allowing for adequate compressive force on the fracture ends. Yet the high stiffness of conventional bone plates significantly reduces compression at the fracture site, and can lead to subsequent bone loss upon healing. Fibre-reinforced composite bone plates have been introduced to address this drawback. However, no studies have optimized their configurations to fulfill the requirements of proper healing. In the present study, classical laminate theory and the finite element method were employed for optimization of a composite bone plate. A hybrid composite made of carbon fibre/epoxy with a flax/epoxy core, which was introduced previously, was optimized by varying the laminate stacking sequence and the contribution of each material, in order to minimize the axial stiffness and maximize the torsional stiffness for a given range of bending stiffness. The initial 14×4(14) possible configurations were reduced to 13 after applying various design criteria. A comprehensive finite element model, validated against a previous experimental study, was used to evaluate the mechanical performance of each composite configuration in terms of its fracture stability, load sharing, and strength in transverse and oblique Vancouver B1 fracture configurations at immediately post-operative, post-operative, and healed bone stages. It was found that a carbon fibre/epoxy plate with an axial stiffness of 4.6 MN, and bending and torsional stiffness of 13 and 14 N·m(2), respectively, showed an overall superiority compared with other laminate configurations. It increased the compressive force at the fracture site up to 14% when compared to a conventional metallic plate, and maintained fracture stability by ensuring the fracture fragments' relative motions were comparable to those found during metallic plate fixation. The healed stage results revealed that implantation of the titanium plate caused a 40.3% reduction in bone stiffness

  20. Physeal Growth Arrest by Excessive Compression: Histological, Biochemical, and Micro-CT Observations in Rabbits

    PubMed Central

    Yoo, Won Joon; Cheon, Jung-Eun; Lee, Hye Ran; Cho, Tae-Joon

    2011-01-01

    Background Compressive force across the growth plate may cause retardation and even arrest of physeal growth. The purpose of this study was to investigate histologic changes, metabolic changes in terms of glycosaminoglycan (GAG) concentration, and contrast-enhanced micro-computed tomography (CEMCT) findings of physeal cartilage in a rabbit model of physeal damage caused by excessive compression. Methods Compressive forces were applied via external fixators for two weeks to the growth plates of distal femurs and proximal tibiae of right hind-legs in 8-week-old rabbits. Left hind-legs remained intact and were used as controls. Forty-four bone specimens containing growth plates of distal femurs or proximal tibiae were harvested one week (n = 12) and four weeks (n = 32) after surgery, and examined for histologic findings (H&E staining) and GAGs quantification in physeal cartilage. After incubation in an ionic contrast material for 48 hours, specimens were scanned by CEMCT, and the pixel values of physeal cartilage were measured. Results CEMCT showed a thin, highly attenuated line parallel to the growth plate in compressed specimens harvested at four weeks after surgery, which was found to be transversely connected trabecular bone. In these specimens, GAG content in physeal cartilage was significantly lower, and CEMCT pixel values of physeal cartilage were significantly higher than in the specimens from the contralateral control side. Conclusions Excessive compressive force applied to growth plates produces altered histologic features and metabolic function in terms of decreased GAG content in physeal cartilage, changes that can be demonstrated by CEMCT. PMID:22162794

  1. Ilizarov hybrid external fixation for fractures of the distal radius: Part II. Internal fixation versus Ilizarov hybrid external fixation: Stability as assessed by cadaveric simulated motion testing.

    PubMed

    Dunning, C E; Lindsay, C S; Bicknell, R T; Johnson, J A; King, G J; Patterson, S D

    2001-03-01

    The in vitro stability of an Ilizarov hybrid external fixator was compared with that of a dorsal 3.5-mm AO T-plate in 8 unpaired, fresh-frozen upper extremities. A specially designed testing device that used computer-controlled pneumatic actuators was used to simulate active finger, wrist, and forearm motions by applying loads to relevant tendons. A comminuted extra-articular distal radius fracture was modelled using a dorsally based wedge osteotomy. Fracture stability was assessed using an electromagnetic tracking device to measure motion across the fracture site after randomized application of the plate and the hybrid fixator. During simulated finger and wrist motions with the forearm pronated or supinated, motion of the distal fragment with the hybrid fixator applied was comparable to or statistically less than with the AO plate applied. During simulated forearm rotation, the stability provided by the 2 fixation types was similar, although the plate allowed statistically less radial-ulnar deviation of the fragment. In this model of a 2-part extra-articular distal radius fracture, the clinically meaningful stability of the Ilizarov hybrid external fixator was comparable to that of the dorsal AO plate.

  2. Biomechanical analysis of the cephalomedullary nail versus the trochanteric stabilizing plate for unstable intertrochanteric femur fractures.

    PubMed

    Walmsley, David; Nicayenzi, Bruce; Kuzyk, Paul Rt; Machin, Alan; Bougherara, Habiba; Schemitsch, Emil H; Zdero, Radovan

    2016-10-26

    Unstable intertrochanteric fractures are commonly treated with a cephalomedullary nail due to high failure rates with a sliding hip screw. The Omega3 Trochanteric Stabilizing Plate is a relatively new device that functions like a modified sliding hip screw with a proximal extension; however, its mechanical properties have not been evaluated. This study biomechanically compared a cephalomedullary nail, that is, Gamma3 Nail against the Omega3 plate. Unstable intertrochanteric fractures were created in 24 artificial femurs. Experimental groups were as follows: Nail (i.e. Gamma3 Nail) (n = 8), Plate A (i.e. Omega3 plate with four distal non-locking screws and no proximal locking screws) (n = 8), Plate B (i.e. Plate A plus five proximal locking screws) (n = 8), Plate C (i.e. Omega3 plate with three distal locking screws and no proximal locking screws) (n = 8), and Plate D (i.e. Plate C plus five proximal locking screws) (n = 8). All specimens were stiffness tested, while the Nail and Plate D groups were also strength tested. For lateral bending, Plate B was less stiff than the Nail (p = 0.001) and Plate A (p = 0.009). For torsion, Plate A was less stiff than Plate D (p = 0.020). For axial compression, the Nail was less stiff than Plate A (p = 0.036) and Plate B (p = 0.008). Axial strength for the Nail (5014 ± 308 N) was 66% higher than the Plate D construct (2940 ± 411 N) (p < 0.001). All Nails failed by partial or complete cutout through the femoral head and neck, but Plate D failed by varus collapse and deformation of the lag screw. When the cephalomedullary nail is clinically contra-indicated, this study supports the use of the Omega3 plate, since it had similar stiffness in three test modes to the Gamma3 Nail, but had lower strength. Stability of Omega3 plate constructs was not improved with locked fixation proximally or distally.

  3. Delayed anterior cervical plate dislodgement with pharyngeal wall perforation and oral extrusion of cervical plate screw after 8 years: A very rare complication

    PubMed Central

    Kapu, Ravindranath; Singh, Manish; Pande, Anil; Vasudevan, Matabushi Chakravarthy; Ramamurthi, Ravi

    2012-01-01

    We report a patient with congenital anomaly of cervical spine, who presented with clinical features suggestive of cervical compressive spondylotic myelopathy. He underwent C3 median corpectomy, graft placement, and stabilization from C2 to C4 vertebral bodies. Postoperative period was uneventful and he improved in his symptoms. Eight years later, he presented with a difficulty in swallowing and occasional regurgitation of feeds of 2 months duration and oral extrusion of screw while having food. On oral examination, there was a defect in the posterior pharyngeal wall through which the upper end of plate with intact self-locking screw and socket of missed fixation screw was seen. This was confirmed on X-ray cervical spine. He underwent removal of the plate system and was fed through nasogastric tube and managed with appropriate antibiotics. This case is presented to report a very rare complication of anterior cervical plate fixation in the form of very late-onset dislodgement, migration of anterior cervical plate, and oral extrusion of screw through perforated posterior pharyngeal wall. PMID:23741125

  4. Mouse tissue fixation.

    PubMed

    Cardiff, Robert D; Miller, Claramae H; Munn, Robert J

    2014-05-01

    One of the primary goals of fixation is to stop postmortem changes that degrade the tissue and allow optimal preservation of morphologic and cytological detail as well as nucleic acid integrity. Following death, tissues soon undergo autolysis, and if organisms from the gastrointestinal, urinary, or respiratory tracts are present, their colonization can soon cause putrefaction. Time is of the essence because warmer temperatures accelerate both types of degradation. Placing the tissue into a fixative stops the postmortem changes. Fixatives have their effect on tissue by cross-linking, coagulation, or a combination of both. This article outlines the basic tissue fixation procedure and offers guidance on choosing an appropriate fixative, the timing and duration of fixation, sample storage, and quality issues.

  5. Segmental Subtotal Corpectomy and Reconstruction With Titanium Cage and Anterior Plate for Multilevel Ossification of the Posterior Longitudinal Ligament.

    PubMed

    Zhang, Tao; Guo, Ying; Hu, Naiwu; Chen, Limin; Wu, Yin; Wang, Yang; Liu, Libing; Zhao, Chengbin

    2016-11-01

    This retrospective study assessed the outcomes of segmental subtotal corpectomy with titanium cage reconstruction and anterior plate fixation for multilevel ossification of the posterior longitudinal ligament. The study included 34 patients with multilevel ossification of the posterior longitudinal ligament who underwent segmental subtotal corpectomy with titanium cage reconstruction and anterior plate fixation from June 2005 to May 2011. Clinical and radiologic data were obtained. Neurologic function was evaluated by Japanese Orthopedic Association scores before and after surgery. No death, paralysis, or other surgically associated injuries occurred. After surgery, the bone graft fusion was firm, with no cases of lack of postoperative bone fusion, broken or loose titanium plate and screws, dislodged titanium cage, or injury to the vertebral artery, nerve root, or spinal cord. Cerebrospinal fluid leakage occurred in 2 cases. Japanese Orthopedic Association scores improved from 6.74±1.82 preoperatively to 11.33±3.5 postoperatively (P<.05). Neurologic outcomes were excellent or good in 84.21% of patients at follow-up of 1 to 6 years. No postoperative cerebrospinal fluid leakage occurred. Reasonable and skilled operation of the pneumatic drill is the key to successful surgery. Anterior corpectomy with titanium cage reconstruction and plate fixation and drilling applications can directly remove the hypertrophy and ossification of the posterior longitudinal ligament and relieve spinal cord compression. This technique retained the integrity of the vertebrae, increasing the possibility of bone graft healing. Segmental subtotal corpectomy with titanium cage reconstruction and anterior plate fixation can be used for the treatment of multilevel ossification of the posterior longitudinal ligament. [Orthopedics. 2016; 39(6):e1140-e1146.].

  6. Guide to radiation fixatives

    SciTech Connect

    Tawil, J.J.; Bold, F.C.

    1983-11-01

    This report identifies and then characterizes a variety of substances available in the market place for potential effectiveness as a fixative on radiologically contaminated surfaces. The substances include both generic chemicals and proprietary products. In selecting a fixative for a particular application, several attributes of the fixative may be relevant to the choice. These attributes include: toxicity, durability, and cleanliness and removability. In addition to the attributes of the fixative, one should also take into account certain characteristics of the site to be treated. These characteristics relate to climate, nature of the surface, use to which the treated surface will be put, subsequent cleanup operations, and type of neighboring surfaces. Finally, costs and potential environmental effects may influence the decision. A variety of fixatives are evaluated with respect to these various attributes and summarized in a reference table.

  7. Cell fixatives for immunostaining.

    PubMed

    Jamur, Maria Célia; Oliver, Constance

    2010-01-01

    Fixation is one of the most critical steps in immunostaining. The object of fixation is to achieve good morphological preservation, while at the same time preserving antigenicity. Tissue blocks, sections, cell cultures or smears are usually immersed in a fixative solution, while in other situations, whole body perfusion of experimental animals is preferable. Fixation can be accomplished by either chemical or physical methods. The chemical methods include cross-linking agents such as formaldehyde, glutaraldehyde and succinimide esters as well as solvents such as acetone and methanol, which precipitate proteins. Of the physical methods, freezing tissue and air drying are most widely used. This chapter deals with the chemical fixation methods most commonly used for light microscopy.

  8. Fuel cell end plate structure

    DOEpatents

    Guthrie, Robin J.; Katz, Murray; Schroll, Craig R.

    1991-04-23

    The end plates (16) of a fuel cell stack (12) are formed of a thin membrane. Pressure plates (20) exert compressive load through insulation layers (22, 26) to the membrane. Electrical contact between the end plates (16) and electrodes (50, 58) is maintained without deleterious making and breaking of electrical contacts during thermal transients. The thin end plate (16) under compressive load will not distort with a temperature difference across its thickness. Pressure plate (20) experiences a low thermal transient because it is insulated from the cell. The impact on the end plate of any slight deflection created in the pressure plate by temperature difference is minimized by the resilient pressure pad, in the form of insulation, therebetween.

  9. Intramedullary Tibial Nail Fixation of Simple Intraarticular Distal Tibia Fractures.

    PubMed

    Scolaro, John A; Broghammer, Francis H; Donegan, Derek J

    2016-11-01

    The optimal treatment strategy for distal tibia fractures, especially those with intraarticular extension, remains controversial. Although open reduction and internal fixation with a plate and screw device is commonly performed for these injuries, the risk of soft tissue complications using this approach is significant. Staged treatment protocols and alternative means of fixation have been proposed to address these undesired events. Although potentially more technically demanding than fixation of diaphyseal or extraarticular tibial fractures, intramedullary nail (IMN) fixation of simple intraarticular distal tibia fractures is a viable treatment alternative with unique advantages. This article presents a review of the literature and rationale for intramedullary tibial nail fixation of simple intraarticular distal tibia fractures and a surgical approach commonly utilized for successful implementation.

  10. Anterior subcutaneous internal fixation for treatment of unstable pelvic fractures

    PubMed Central

    2014-01-01

    Background Fractures of the pelvic ring including disruption of the posterior elements in high-energy trauma have both high morbidity and mortality rates. For some injury pattern part of the initial resuscitation includes either external fixation or plate fixation to close the pelvic ring and decrease blood loss. In certain situations – especially when associated with abdominal trauma and the need to perform laparotomies – both techniques may put the patient at risk of either pintract or deep plate infections. We describe an operative approach to percutaneously close and stabilize the pelvic ring using spinal implants as an internal fixator and report the results in a small series of patients treated with this technique during the resuscitation phase. Findings Four patients were treated by subcutaneous placement of an internal fixator. Screw fixation was carried out by minimally invasive placement of two supra-acetabular iliac screws. Afterwards, a subcutaneous transfixation rod was inserted and attached to the screws after reduction of the pelvic ring. All patients were allowed to fully weight-bear. No losses of reduction or deep infections occurred. Fracture healing was uneventful in all cases. Conclusion Minimally invasive fixation is an alternative technique to stabilize the pelvic ring. The clinical results illustrate that this technique is able to achieve good results in terms of maintenance of reduction the pelvic ring. Also, abdominal surgeries no longer put the patient at risk of infected pins or plates. PMID:24606833

  11. The stability following advancement genioplasty with biodegradable screw fixation.

    PubMed

    Lee, Gyu-Tae; Jung, Hwi-Dong; Kim, Sang Yoon; Park, Hyung-Sik; Jung, Young-Soo

    2014-04-01

    The purpose of this study was to compare postoperative stability using biodegradable screws with that of metal plates for fixation of advancement genioplasty. We studied patients who had advancement genioplasty alone or at the same time as other orthognathic surgery including mandibular setback. We assessed the lateral cephalographs at different time points (preoperatively, and 7 days, 3 months, 6 months, and 12 months postoperatively). A total of 54 patients were enrolled and 27 patients were assigned to each group. The position of pogonion was stable 12 months postoperatively, and the amount of skeletal advancement was reflected in soft tissue close to 100%. There were no clinical differences between biodegradable screws and conventional metal plates used for fixation. Biodegradable fixation for advancement genioplasty is a good option for patients who would require a second operation for removal of the plates.

  12. Mechanical design optimization of bioabsorbable fixation devices for bone fractures.

    PubMed

    Lovald, Scott T; Khraishi, Tariq; Wagner, Jon; Baack, Bret

    2009-03-01

    Bioabsorbable bone plates can eliminate the necessity for a permanent implant when used to fixate fractures of the human mandible. They are currently not in widespread use because of the low strength of the materials and the requisite large volume of the resulting bone plate. The aim of the current study was to discover a minimally invasive bioabsorbable bone plate design that can provide the same mechanical stability as a standard titanium bone plate. A finite element model of a mandible with a fracture in the body region is subjected to bite loads that are common to patients postsurgery. The model is used first to determine benchmark stress and strain values for a titanium plate. These values are then set as the limits within which the bioabsorbable bone plate must comply. The model is then modified to consider a bone plate made of the polymer poly-L/DL-lactide 70/30. An optimization routine is run to determine the smallest volume of bioabsorbable bone plate that can perform and a titanium bone plate when fixating fractures of this considered type. Two design parameters are varied for the bone plate design during the optimization analysis. The analysis determined that a strut style poly-L-lactide-co-DL-lactide plate of 690 mm2 can provide as much mechanical stability as a similar titanium design structure of 172 mm2. The model has determined a bioabsorbable bone plate design that is as strong as a titanium plate when fixating fractures of the load-bearing mandible. This is an intriguing outcome, considering that the polymer material has only 6% of the stiffness of titanium.

  13. Data Compression.

    ERIC Educational Resources Information Center

    Bookstein, Abraham; Storer, James A.

    1992-01-01

    Introduces this issue, which contains papers from the 1991 Data Compression Conference, and defines data compression. The two primary functions of data compression are described, i.e., storage and communications; types of data using compression technology are discussed; compression methods are explained; and current areas of research are…

  14. Four-corner arthrodesis with a locking, dorsal circular polyether-ether-ketone (PEEK-Optima) plate.

    PubMed

    Rhee, Peter C; Kakar, Sanjeev; Shin, Alexander Y

    2012-12-01

    Scaphoidectomy and 4-corner arthrodesis can be a successful salvage procedure for scaphoid nonunion advanced collapse and scapholunate advanced collapse. Traditional methods of fixation include Kirschner wires, staples, and/or headless compression screws. Nonlocking, dorsal circular plates, manufactured from stainless steel, have been advocated to allow early wrist range of motion and improved union rates. However, the reported union rates have been variable and inconsistent. This wide results have been attributed to the difficulty in assessing union with plain film radiograph due to the radio-opaque plate. Recently, a locking, dorsal circular plate, comprised of a radiolucent polyether-ether-ketone (PEEK-Optima), has been introduced with the additional benefit of providing a fixed-angle construct and allowing a more accurate assessment of bone union with plain film imaging studies.

  15. Effects of a sliding plate on morphology of the epiphyseal plate in goat distal femur.

    PubMed

    Lin, Da-sheng; Lian, Ke-jian; Hong, Jia-yuan; Ding, Zhen-qi; Zhai, Wen-liang

    2012-01-01

    The aim of this study was to observe the effects of a sliding plate on the morphology of the epiphyseal plate in goat distal femur. Eighteen premature female goats were divided randomly into sliding plate, regular plate and control groups. Radiographic analysis and histological staining were performed to evaluate the development of epiphyseal plate at 4 and 8 weeks after surgery. In the sliding plate group, the plate extended accordingly as the epiphyseal plate grows, and the epiphyseal morphology was kept essential normal. However, the phenomenon of the epiphyseal growth retardation and premature closure were very common in the regular plate group. In addition, the sliding plate group exhibited more normal histologic features and Safranin O staining compared to the regular plate group. Our results suggest that the sliding plate can provide reliable internal fixation of epiphyseal fracture without inhibiting epiphyseal growth.

  16. Effects of a Sliding Plate on Morphology of the Epiphyseal Plate in Goat Distal Femur

    PubMed Central

    LIN, Da-sheng; LIAN, Ke-jian; HONG, Jia-yuan; DING, Zhen-qi; ZHAI, Wen-liang

    2012-01-01

    The aim of this study was to observe the effects of a sliding plate on the morphology of the epiphyseal plate in goat distal femur. Eighteen premature female goats were divided randomly into sliding plate, regular plate and control groups. Radiographic analysis and histological staining were performed to evaluate the development of epiphyseal plate at 4 and 8 weeks after surgery. In the sliding plate group, the plate extended accordingly as the epiphyseal plate grows, and the epiphyseal morphology was kept essential normal. However, the phenomenon of the epiphyseal growth retardation and premature closure were very common in the regular plate group. In addition, the sliding plate group exhibited more normal histologic features and Safranin O staining compared to the regular plate group. Our results suggest that the sliding plate can provide reliable internal fixation of epiphyseal fracture without inhibiting epiphyseal growth. PMID:22359485

  17. Submuscular plating after distraction osteogenesis in children.

    PubMed

    Oh, Chang-Wug; Shetty, Gautam M; Song, Hae-Ryong; Kyung, Hee-Soo; Oh, Jong-Keon; Min, Woo-Kie; Lee, Byung-Woo; Park, Byung-Chul

    2008-09-01

    Although distraction osteogenesis has solved limb length discrepancies, many complications are inevitable from long duration of external fixation. Use of intramedullary nails for early removal of fixators has its own challenges especially in pediatric age group. To facilitate early removal of external fixators in children, we tried a novel method of submuscular plating over the distraction callus, which is described, and the results and complications of this technique are presented. In eight children (four girls and four boys), of limb lengthening (four cases) and bone transport (four cases) done in three femurs and five tibiae with external fixators (five Ilizarov ring fixators and three monofixators), submuscular plating was done over the distraction callus. The causes of limb length discrepancy included traumatic and septic growth arrest, congenital pseudoarthrosis of tibia, fibular hemimelia, tumor salvage, and Perthes' disease. The purpose of plating was to remove the external fixator earlier after achieving the target length. Mean age of plating procedure was 11.62 years, and mean amount of distraction was 5.47 cm. In all patients, the distraction callus healed on maintaining its length or correcting into the original alignment. The mean external fixation index was 26.93 days/cm and healing index was 52.01 days/cm. One complication of superficial pin-track infection occurred, which resolved completely with conservative treatment. None of the patients developed deep infection or implant failures. The mean follow-up after plating was 28 months (range, 18-62 months). Submuscular plating over the distraction callus may be a successful method that permits early removal of fixator with fewer complications. This method can be a useful alternative in children or when nailing is difficult.

  18. The halo fixator.

    PubMed

    Bono, Christopher M

    2007-12-01

    The halo fixator may be used for the definitive treatment of cervical spine trauma, preoperative reduction in the patient with spinal deformity, and adjunctive postoperative stabilization following cervical spine surgery. Halo fixation decreases cervical motion by 30% to 96%. Absolute contraindications include cranial fracture, infection, and severe soft-tissue injury at the proposed pin sites. Relative contraindications include severe chest trauma, obesity, advanced age, and a barrel-shaped chest. In children, a computed tomography scan of the head should be obtained before pin placement to determine cranial bone thickness. Complications of halo fixation include pin loosening, pin site infection, and skin breakdown. A concerning rate of life-threatening complications, such as respiratory distress, has been reported in elderly patients. Despite a paucity of contemporary data, recent retrospective studies have demonstrated acceptable results for halo fixation in managing some upper and lower cervical spine injuries.

  19. Photographic fixative poisoning

    MedlinePlus

    Photographic fixatives are chemicals used to develop photographs. This article discusses poisoning from swallowing such chemicals. This article is for information only. DO NOT use it to treat or manage an ...

  20. [The use of blade plate and dynamic screw plate osteosynthesis].

    PubMed

    Oestern, H J; Gänsslen, A

    2010-02-01

    Osteosynthesis in fracture treatment and in some reconstructive procedures with blade plates or dynamic screw systems was the standard procedure for several decades. In this review, the current options and concepts using blade plate osteosynthesis, stabilization of proximal and distal femur fractures and reconstructive procedures with the dynamic hip screw or the dynamic condylar blade are discussed. On the basis of a literature review, the present indications, results and region-specific complications are reported and discussed.Blade plates are used mainly in the context of reconstructive procedures, as well as in the treatment of pseudoarthroses. The Pauwel procedure in femoral neck non-unions is one of the best known indications. In contrast, the dynamic hip screw is the gold standard for stabilization of femoral neck and most pertrochanteric fractures, whereas the dynamic condylar screw is still an alternative to internal fixators for proximal and distal femoral fracture fixations.

  1. Mechanical testing of a device for subcutaneous internal anterior pelvic ring fixation versus external pelvic ring fixation

    PubMed Central

    2014-01-01

    Background Although useful in the emergency treatment of pelvic ring injuries, external fixation is associated with pin tract infections, the patient’s limited mobility and a restricted surgical accessibility to the lower abdomen. In this study, the mechanical stability of a subcutaneous internal anterior fixation (SIAF) system is investigated. Methods A standard external fixation and a SIAF system were tested on pairs of Polyoxymethylene testing cylinders using a universal testing machine. Each specimen was subjected to a total of 2000 consecutive cyclic loadings at 1 Hz with sinusoidal lateral compression/distraction (+/−50 N) and torque (+/− 0.5 Nm) loading alternating every 200 cycles. Translational and rotational stiffness were determined at 100, 300, 500, 700 and 900 cycles. Results There was no significant difference in translational stiffness between the SIAF and the standard external fixation when compared at 500 (p = .089), 700 (p = .081), and 900 (p = .266) cycles. Rotational stiffness observed for the SIAF was about 50 percent higher than the standard external fixation at 300 (p = .005), 500 (p = .020), and 900 (p = .005) cycles. No loosening or failure of the rod-pin/rod-screw interfaces was seen. Conclusions In comparison with the standard external fixation system, the tested device for subcutaneous internal anterior fixation (SIAF) in vitro has similar translational and superior rotational stiffness. PMID:24684828

  2. Improving Carbon Fixation Pathways

    PubMed Central

    Ducat, Daniel C.

    2012-01-01

    A recent resurgence in basic and applied research on photosynthesis has been driven in part by recognition that fulfilling future food and energy requirements will necessitate improvements in crop carbon-fixation efficiencies. Photosynthesis in traditional terrestrial crops is being reexamined in light of molecular strategies employed by photosynthetic microbes to enhance the activity of the Calvin cycle. Synthetic biology is well-situated to provide original approaches for compartmentalizing and enhancing photosynthetic reactions in a species independent manner. Furthermore, the elucidation of alternative carbon-fixation routes distinct from the Calvin cycle raises possibilities that alternative pathways and organisms can be utilized to fix atmospheric carbon dioxide into useful materials. PMID:22647231

  3. Limits of internal fixation in long-bone fracture.

    PubMed

    Nieto, H; Baroan, C

    2017-02-01

    Alternatives to internal fixation of long-bone fracture comprise, depending on location, external fixation or joint replacement. Limitations comprise risk of infection and functional outcome quality, which vary according to technique. The present study examines these limitations, based on comparative or large-scale studies from which certain significant results emerge. Four main questions are dealt with: (1) the present role of locking plates; (2) conditions for intramedullary nailing in Gustilo grade IIIb open fracture; (3) the limitations of conversion from external fixation to intramedullary nailing in open lower leg fracture; (4) and the limitations of definitive anterograde femoral nailing in multiple trauma. Locking plate fixation has yet to prove clinical superiority in any of the anatomic sites for which good-quality comparative analyses are available. Infection risk in Gustilo grade IIIb open lower leg fracture is equivalent when treated by intramedullary nailing or external fixation, if wound care and debridement are effective, antibiotherapy is initiated rapidly and skin cover is restored within 7days. Conversion from primary external fixation to intramedullary nailing is possible if the external fixator was fitted less than 28days previously and skin cover was restored within 7days. The pulmonary and systemic impact of peripheral lesions or definitive anterograde intramedullary nailing of femoral fracture in multiple trauma calls for caution and what is known as "damage-control orthopedics" (DCO), a term covering the general consequences of both the initial trauma and its treatment. Femoral intramedullary nailing is thus contraindicated in case of hemorrhagic shock (blood pressure<90mmHg), hypothermia (<33°C), coagulation disorder (platelet count<90,000) or peripheral lesions such as multiple long-bone fractures, crushed limb or primary pulmonary contusion. In such cases, external fixation or retrograde nailing with a small-diameter nail and without

  4. Plating of patella fractures: techniques and outcomes.

    PubMed

    Taylor, Benjamin C; Mehta, Sanjay; Castaneda, Joaquin; French, Bruce G; Blanchard, Chris

    2014-09-01

    Operative treatment of displaced patella fractures with tension band fixation remains the gold standard, but is associated with a significant rate of complications and symptomatic implants. Despite the evolution of tension band fixation to include cannulated screws, surprisingly little other development has been made to improve overall patient outcomes. In this article, we present the techniques and outcomes of patella plating for displaced patella fractures and patella nonunions.

  5. Biomechanical study of different plate configurations for distal humerus osteosynthesis.

    PubMed

    Bogataj, M; Kosel, F; Norris, R; Krkovic, M; Brojan, M

    2015-05-01

    Fractures of the distal humerus are most commonly fixed by open reduction and internal fixation, using plates and screws, either in a locking or in a non-locking construct. Three different plating systems are commonly used in practice. The most important differences between them are in plate orientation, which affects both the rigidity of the osteosynthesis and invasiveness of the surgical procedure. Unfortunately, there is no common agreement between surgeons about which plate configuration brings the best clinical outcome. In this study, we investigate the theoretical rigidity of plate osteosyntheses considering two types of AO/ASIF configurations (90° angle between plates), Mayo clinic (Acumed) configuration (180° between plates) and dorsal fixation of both plates. We also compared the results for cases with and without contact between the bone fragments. In the case of no bone contact, the Mayo clinic plate configuration is found to be the most rigid, followed by both AO/ASIF plate configurations, and the least rigid system is the Korosec plate configuration. On the other hand, no significant differences between all types of fixation configurations are found in cases with contact in-between the bone fragments. Our findings show that this contact is very important and can compensate for the lack of load carrying capacity of the implants. This could therefore incite other implant fixation solutions, leading to less invasive surgical procedures and consequently improved clinical outcome.

  6. DNABIT Compress - Genome compression algorithm.

    PubMed

    Rajarajeswari, Pothuraju; Apparao, Allam

    2011-01-22

    Data compression is concerned with how information is organized in data. Efficient storage means removal of redundancy from the data being stored in the DNA molecule. Data compression algorithms remove redundancy and are used to understand biologically important molecules. We present a compression algorithm, "DNABIT Compress" for DNA sequences based on a novel algorithm of assigning binary bits for smaller segments of DNA bases to compress both repetitive and non repetitive DNA sequence. Our proposed algorithm achieves the best compression ratio for DNA sequences for larger genome. Significantly better compression results show that "DNABIT Compress" algorithm is the best among the remaining compression algorithms. While achieving the best compression ratios for DNA sequences (Genomes),our new DNABIT Compress algorithm significantly improves the running time of all previous DNA compression programs. Assigning binary bits (Unique BIT CODE) for (Exact Repeats, Reverse Repeats) fragments of DNA sequence is also a unique concept introduced in this algorithm for the first time in DNA compression. This proposed new algorithm could achieve the best compression ratio as much as 1.58 bits/bases where the existing best methods could not achieve a ratio less than 1.72 bits/bases.

  7. The Fixation of Nitrogen.

    ERIC Educational Resources Information Center

    Andrew, S. P. S.

    1978-01-01

    Discusses the fixation of atmospheric nitrogen in the form of ammonia as one of the foundations of modern chemical industry. The article describes ammonia production and synthesis, purifying the hydrogen-nitrogen mix, nitric acid production, and its commericial plant. (HM)

  8. Plate motion

    SciTech Connect

    Gordon, R.G. )

    1991-01-01

    The motion of tectonic plates on the earth is characterized in a critical review of U.S. research from the period 1987-1990. Topics addressed include the NUVEL-1 global model of current plate motions, diffuse plate boundaries and the oceanic lithosphere, the relation between plate motions and distributed deformations, accelerations and the steadiness of plate motions, the distribution of current Pacific-North America motion across western North America and its margin, plate reconstructions and their uncertainties, hotspots, and plate dynamics. A comprehensive bibliography is provided. 126 refs.

  9. Difficulty in Fixation of the Volar Lunate Facet Fragment in Distal Radius Fracture

    PubMed Central

    Obata, Hiroyuki; Futamura, Kentaro; Obayashi, Osamu; Mogami, Atsuhiko; Tsuji, Hideki; Kurata, Yoshiaki; Kaneko, Kazuo

    2017-01-01

    Recent reports suggest the presence of a rare fracture type for which reduction and fixation cannot be achieved with volar locking plate (VLP). In particular, it is difficult to achieve reduction and fixation with volar lunate facet (VLF) fragments present on the volar ulnar aspect of the lunate facet, because of the anatomical structure and biomechanics in this region. Herein, we report two challenging cases of difficulty in fixation of the VLF fragment in distal radius fracture. For this fracture type, it is most important to identify the volar ulnar bone fragment before surgery; it may also be necessary to optimize distal placement of the VLP via a dual-window approach and to apply additional fixations, such as a small plate, anchor, and/or external fixation. PMID:28255487

  10. Compression arthrodesis of the small joints of the hand.

    PubMed

    Seitz, W H; Sellman, D C; Scarcella, J B; Froimson, A I

    1994-07-01

    A number of techniques for achieving small joint arthrodesis in the hand combine various forms of internal fixation with external cast or splint immobilization. Rates of arthrodesis in most cases are quite high. However, the prolonged period of adjacent joint immobilization from casting can extend rehabilitation time and limit hand function during healing. Compression arthrodesis has been used effectively in a number of larger joints, such as the knee and ankle. Miniaturization of existing external fixation compression devices now enables the application of this principle to the small joints of the hand. A series of 20 metacarpophalangeal and interphalangeal joints underwent arthrodesis in which a miniature external fixation/compression frame was used. Nineteen of 20 joints demonstrated complete primary arthrodesis within 6 weeks; one fibrous union developed in a distal interphalangeal joint and no postoperative deformities occurred. Complete stabilization was provided by the fixator, thus allowing immediate postoperative adjacent joint function.

  11. New technique for fixing rib fracture with bioabsorbable plate.

    PubMed

    Oyamatsu, Hironori; Ohata, Norihisa; Narita, Kunio

    2016-09-01

    Fixation of a bone fracture with a bioabsorbable plate made of poly-L-lactide and hydroxyapatite has received attention. We adopted this technique for a rib fracture by bending the plate into a U-shape and fixing it with suture through the holes in the mesh of the plate and holes that are drilled in the edge of the fractured rib. The suture is also wound around the plate.

  12. Scapular thickness--implications for fracture fixation.

    PubMed

    Burke, Charity S; Roberts, Craig S; Nyland, John A; Radmacher, Paula G; Acland, Robert D; Voor, Michael J

    2006-01-01

    The purpose of this study was to measure and map scapula osseous thickness to identify the optimal areas for internal fixation. Eighteen (9 pairs) scapulae from 2 female and 7 male cadavers were used. After harvest and removal of all soft tissues, standardized measurement lines were made based on anatomic landmarks. For consistency among scapulae, measurements were taken at standard percentage intervals along each line approximating the distance between two consecutive reconstruction plate screw holes. Two-mm-diameter drill holes were made at each point, and a standard depth gauge was used to measure thickness. The glenoid fossa (25 mm) displayed the greatest mean osseous thickness, followed by the lateral scapular border (9.7 mm), the scapula spine (8.3 mm), and the central portion of the body of the scapula (3.0 mm). To optimize screw purchase and internal fixation strength, the lateral border, the lateral aspect of the base of the scapula spine, and the scapula spine itself should be used for anatomic sites of internal fixation of scapula fractures.

  13. Compression embedding

    DOEpatents

    Sandford, M.T. II; Handel, T.G.; Bradley, J.N.

    1998-07-07

    A method and apparatus for embedding auxiliary information into the digital representation of host data created by a lossy compression technique and a method and apparatus for constructing auxiliary data from the correspondence between values in a digital key-pair table with integer index values existing in a representation of host data created by a lossy compression technique are disclosed. The methods apply to data compressed with algorithms based on series expansion, quantization to a finite number of symbols, and entropy coding. Lossy compression methods represent the original data as ordered sequences of blocks containing integer indices having redundancy and uncertainty of value by one unit, allowing indices which are adjacent in value to be manipulated to encode auxiliary data. Also included is a method to improve the efficiency of lossy compression algorithms by embedding white noise into the integer indices. Lossy compression methods use loss-less compression to reduce to the final size the intermediate representation as indices. The efficiency of the loss-less compression, known also as entropy coding compression, is increased by manipulating the indices at the intermediate stage. Manipulation of the intermediate representation improves lossy compression performance by 1 to 10%. 21 figs.

  14. Compression embedding

    DOEpatents

    Sandford, II, Maxwell T.; Handel, Theodore G.; Bradley, Jonathan N.

    1998-01-01

    A method and apparatus for embedding auxiliary information into the digital representation of host data created by a lossy compression technique and a method and apparatus for constructing auxiliary data from the correspondence between values in a digital key-pair table with integer index values existing in a representation of host data created by a lossy compression technique. The methods apply to data compressed with algorithms based on series expansion, quantization to a finite number of symbols, and entropy coding. Lossy compression methods represent the original data as ordered sequences of blocks containing integer indices having redundancy and uncertainty of value by one unit, allowing indices which are adjacent in value to be manipulated to encode auxiliary data. Also included is a method to improve the efficiency of lossy compression algorithms by embedding white noise into the integer indices. Lossy compression methods use loss-less compression to reduce to the final size the intermediate representation as indices. The efficiency of the loss-less compression, known also as entropy coding compression, is increased by manipulating the indices at the intermediate stage. Manipulation of the intermediate representation improves lossy compression performance by 1 to 10%.

  15. Novel posterior fixation keratoprosthesis

    NASA Astrophysics Data System (ADS)

    Lacombe, Emmanuel

    1992-08-01

    The keratoprosthesis is the last solution for corneally blind patients that cannot benefit from corneal transplants. Keratoprostheses that have been designed to be affixed anteriorly usually necessitate multi-step surgical procedures and are continuously subjected to the extrusion forces generated by the positive intraocular pressure; therefore, clinical results in patients prove inconsistent. We proposed a novel keratoprosthesis concept that utilizes posterior corneal fixation which `a priori' minimizes the risk of aqueous leakage and expulsion. This prosthesis is implanted in a single procedure thereby reducing the number of surgical complications normally associated with anterior fixation devices. In addition, its novel design makes this keratoprosthesis implantable in phakic eyes. With an average follow-up of 13 months (range 3 to 25 months), our results on 21 cases are encouraging. Half of the keratoprostheses were implanted in severe burn cases, with the remainder in cases of pseudo- pemphigus. Good visual results and cosmetic appearance were obtained in 14 of 21 eyes.

  16. Biomechanical analysis of a new carbon fiber/flax/epoxy bone fracture plate shows less stress shielding compared to a standard clinical metal plate.

    PubMed

    Bagheri, Zahra S; Tavakkoli Avval, Pouria; Bougherara, Habiba; Aziz, Mina S R; Schemitsch, Emil H; Zdero, Radovan

    2014-09-01

    Femur fracture at the tip of a total hip replacement (THR), commonly known as Vancouver B1 fracture, is mainly treated using rigid metallic bone plates which may result in "stress shielding" leading to bone resorption and implant loosening. To minimize stress shielding, a new carbon fiber (CF)/Flax/Epoxy composite plate has been developed and biomechanically compared to a standard clinical metal plate. For fatigue tests, experiments were done using six artificial femurs cyclically loaded through the femoral head in axial compression for four stages: Stage 1 (intact), stage 2 (after THR insertion), stage 3 (after plate fixation of a simulated Vancouver B1 femoral midshaft fracture gap), and stage 4 (after fracture gap healing). For fracture fixation, one group was fitted with the new CF/Flax/Epoxy plate (n = 3), whereas another group was repaired with a standard clinical metal plate (Zimmer, Warsaw, IN) (n = 3). In addition to axial stiffness measurements, infrared thermography technique was used to capture the femur and plate surface stresses during the testing. Moreover, finite element analysis (FEA) was performed to evaluate the composite plate's axial stiffness and surface stress field. Experimental results showed that the CF/Flax/Epoxy plated femur had comparable axial stiffness (fractured = 645 ± 67 N/mm; healed = 1731 ± 109 N/mm) to the metal-plated femur (fractured = 658 ± 69 N/mm; healed = 1751 ± 39 N/mm) (p = 1.00). However, the bone beneath the CF/Flax/Epoxy plate was the only area that had a significantly higher average surface stress (fractured = 2.10 ± 0.66 MPa; healed = 1.89 ± 0.39 MPa) compared to bone beneath the metal plate (fractured = 1.18 ± 0.93 MPa; healed = 0.71 ± 0.24 MPa) (p < 0.05). FEA bone surface stresses yielded peak of 13 MPa at distal epiphysis (stage 1), 16 MPa at distal epiphysis (stage 2), 85 MPa for composite and 129

  17. CARBON DIOXIDE FIXATION.

    SciTech Connect

    FUJITA,E.

    2000-01-12

    Solar carbon dioxide fixation offers the possibility of a renewable source of chemicals and fuels in the future. Its realization rests on future advances in the efficiency of solar energy collection and development of suitable catalysts for CO{sub 2} conversion. Recent achievements in the efficiency of solar energy conversion and in catalysis suggest that this approach holds a great deal of promise for contributing to future needs for fuels and chemicals.

  18. Effects of overmodulation in fixation-free rehalogenating bleached holograms

    NASA Astrophysics Data System (ADS)

    Neipp, Cristian; Pascual, Inmaculada; Beléndez, Augusto

    2001-07-01

    The mechanism for hologram formation by fixation-free rehalogenating bleaching has been treated by several authors. Experiments carried out with Kodak and Agfa photographic plates have led to the conclusion that the transfer of material from the exposed to the unexposed zones is the main mechanism that drives the process. We show that when BB-640 emulsion is used in the recording of holograms by means of fixation-free rehalogenating bleaching, the mechanism for the transfer of material from exposed to unexposed zones is efficient enough to create high refractive-index modulations. We also comment on the overmodulation effects, which result in a decrease in diffraction efficiency.

  19. Compression embedding

    DOEpatents

    Sandford, II, Maxwell T.; Handel, Theodore G.; Bradley, Jonathan N.

    1998-01-01

    A method of embedding auxiliary information into the digital representation of host data created by a lossy compression technique. The method applies to data compressed with lossy algorithms based on series expansion, quantization to a finite number of symbols, and entropy coding. Lossy compression methods represent the original data as integer indices having redundancy and uncertainty in value by one unit. Indices which are adjacent in value are manipulated to encode auxiliary data. By a substantially reverse process, the embedded auxiliary data can be retrieved easily by an authorized user. Lossy compression methods use loss-less compressions known also as entropy coding, to reduce to the final size the intermediate representation as indices. The efficiency of the compression entropy coding, known also as entropy coding is increased by manipulating the indices at the intermediate stage in the manner taught by the method.

  20. Compression embedding

    DOEpatents

    Sandford, M.T. II; Handel, T.G.; Bradley, J.N.

    1998-03-10

    A method of embedding auxiliary information into the digital representation of host data created by a lossy compression technique is disclosed. The method applies to data compressed with lossy algorithms based on series expansion, quantization to a finite number of symbols, and entropy coding. Lossy compression methods represent the original data as integer indices having redundancy and uncertainty in value by one unit. Indices which are adjacent in value are manipulated to encode auxiliary data. By a substantially reverse process, the embedded auxiliary data can be retrieved easily by an authorized user. Lossy compression methods use loss-less compressions known also as entropy coding, to reduce to the final size the intermediate representation as indices. The efficiency of the compression entropy coding, known also as entropy coding is increased by manipulating the indices at the intermediate stage in the manner taught by the method. 11 figs.

  1. Transverse Compression of Tendons.

    PubMed

    Salisbury, S T Samuel; Buckley, C Paul; Zavatsky, Amy B

    2016-04-01

    A study was made of the deformation of tendons when compressed transverse to the fiber-aligned axis. Bovine digital extensor tendons were compression tested between flat rigid plates. The methods included: in situ image-based measurement of tendon cross-sectional shapes, after preconditioning but immediately prior to testing; multiple constant-load creep/recovery tests applied to each tendon at increasing loads; and measurements of the resulting tendon displacements in both transverse directions. In these tests, friction resisted axial stretch of the tendon during compression, giving approximately plane-strain conditions. This, together with the assumption of a form of anisotropic hyperelastic constitutive model proposed previously for tendon, justified modeling the isochronal response of tendon as that of an isotropic, slightly compressible, neo-Hookean solid. Inverse analysis, using finite-element (FE) simulations of the experiments and 10 s isochronal creep displacement data, gave values for Young's modulus and Poisson's ratio of this solid of 0.31 MPa and 0.49, respectively, for an idealized tendon shape and averaged data for all the tendons and E = 0.14 and 0.10 MPa for two specific tendons using their actual measured geometry. The compression load versus displacement curves, as measured and as simulated, showed varying degrees of stiffening with increasing load. This can be attributed mostly to geometrical changes in tendon cross section under load, varying according to the initial 3D shape of the tendon.

  2. Effects of Prism Eyeglasses on Objective and Subjective Fixation Disparity.

    PubMed

    Schroth, Volkhard; Joos, Roland; Jaschinski, Wolfgang

    2015-01-01

    In optometry of binocular vision, the question may arise whether prisms should be included in eyeglasses to compensate an oculomotor and/or sensory imbalance between the two eyes. The corresponding measures of objective and subjective fixation disparity may be reduced by the prisms, or the adaptability of the binocular vergence system may diminish effects of the prisms over time. This study investigates effects of wearing prisms constantly for about 5 weeks in daily life. Two groups of 12 participants received eyeglasses with prisms having either a base-in direction or a base-out direction with an amount up to 8 prism diopters. Prisms were prescribed based on clinical fixation disparity test plates at 6 m. Two dependent variables were used: (1) subjective fixation disparity was indicated by a perceived offset of dichoptic nonius lines that were superimposed on the fusion stimuli and (2) objective fixation disparity was measured with a video based eye tracker relative to monocular calibration. Stimuli were presented at 6 m and included either central or more peripheral fusion stimuli. Repeated measurements were made without the prisms and with the prisms after about 5 weeks of wearing these prisms. Objective and subjective fixation disparity were correlated, but the type of fusion stimulus and the direction of the required prism may play a role. The prisms did not reduce the fixation disparity to zero, but induced significant changes in fixation disparity with large effect sizes. Participants receiving base-out prisms showed hypothesized effects, which were concurrent in both types of fixation disparity. In participants receiving base-in prisms, the individual effects of subjective and objective effects were negatively correlated: the larger the subjective (sensory) effect, the smaller the objective (motor) effect. This response pattern was related to the vergence adaptability, i.e. the individual fusional vergence reserves.

  3. Compressive Holography

    NASA Astrophysics Data System (ADS)

    Lim, Se Hoon

    Compressive holography estimates images from incomplete data by using sparsity priors. Compressive holography combines digital holography and compressive sensing. Digital holography consists of computational image estimation from data captured by an electronic focal plane array. Compressive sensing enables accurate data reconstruction by prior knowledge on desired signal. Computational and optical co-design optimally supports compressive holography in the joint computational and optical domain. This dissertation explores two examples of compressive holography: estimation of 3D tomographic images from 2D data and estimation of images from under sampled apertures. Compressive holography achieves single shot holographic tomography using decompressive inference. In general, 3D image reconstruction suffers from underdetermined measurements with a 2D detector. Specifically, single shot holographic tomography shows the uniqueness problem in the axial direction because the inversion is ill-posed. Compressive sensing alleviates the ill-posed problem by enforcing some sparsity constraints. Holographic tomography is applied for video-rate microscopic imaging and diffuse object imaging. In diffuse object imaging, sparsity priors are not valid in coherent image basis due to speckle. So incoherent image estimation is designed to hold the sparsity in incoherent image basis by support of multiple speckle realizations. High pixel count holography achieves high resolution and wide field-of-view imaging. Coherent aperture synthesis can be one method to increase the aperture size of a detector. Scanning-based synthetic aperture confronts a multivariable global optimization problem due to time-space measurement errors. A hierarchical estimation strategy divides the global problem into multiple local problems with support of computational and optical co-design. Compressive sparse aperture holography can be another method. Compressive sparse sampling collects most of significant field

  4. Comparison of theoretical fixation stability of three devices employed in medial opening wedge high tibial osteotomy: a finite element analysis

    PubMed Central

    2014-01-01

    Background Medial open wedge high tibial osteotomy is a well-established procedure for the treatment of unicompartmental osteoarthritis and symptomatic varus malalignment. We hypothesized that different fixation devices generate different fixation stability profiles for the various wedge sizes in a finite element (FE) analysis. Methods Four types of fixation were compared: 1) first and 2) second generation Puddu plates, and 3) TomoFix plate with and 4) without bone graft. Cortical and cancellous bone was modelled and five different opening wedge sizes were studied for each model. Outcome measures included: 1) stresses in bone, 2) relative displacement of the proximal and distal tibial fragments, 3) stresses in the plates, 4) stresses on the upper and lower screw surfaces in the screw channels. Results The highest load for all fixation types occurred in the plate axis. For the vast majority of the wedge sizes and fixation types the shear stress (von Mises stress) was dominating in the bone independent of fixation type. The relative displacements of the tibial fragments were low (in μm range). With an increasing wedge size this displacement tended to increase for both Puddu plates and the TomoFix plate with bone graft. For the TomoFix plate without bone graft a rather opposite trend was observed. For all fixation types the occurring stresses at the screw-bone contact areas pulled at the screws and exceeded the allowable threshold of 1.2 MPa for at least one screw surface. Of the six screw surfaces that were studied, the TomoFix plate with bone graft showed a stress excess of one out of twelve and without bone graft, five out of twelve. With the Puddu plates, an excess stress occurred in the majority of screw surfaces. Conclusions The different fixation devices generate different fixation stability profiles for different opening wedge sizes. Based on the computational simulations, none of the studied osteosynthesis fixation types warranted an intransigent full

  5. Biomechanical investigation of two plating systems for medial column fusion in foot

    PubMed Central

    Simons, Paul; Sommerer, Theresia; Zderic, Ivan; Wahl, Dieter; Lenz, Mark; Skulev, Hristo; Knobe, Matthias; Gueorguiev, Boyko; Richards, R. Geoff; Klos, Kajetan

    2017-01-01

    Background Arthrodesis of the medial column (navicular, cuneiform I and metatarsal I) is performed for reasons such as Charcot arthropathy, arthritis, posttraumatic reconstruction or severe pes planus. However, the complication rate is still high and mainly resulting from inadequate fixation. Special plates, designed for medial column arthrodesis, seem to offer potential to reduce the complication rate. The aim of this study was to investigate biomechanically plantar and dorsomedial fusion of the medial column using two new plating systems. Methods Eight matched pairs of human cadaveric lower legs were randomized in two groups and medial column fusion was performed using either plantar or dorsomedial variable-angle locking compression plates. The specimens were biomechanically tested under cyclic progressively increasing axial loading with physiological profile of each cycle. In addition to the machine data, mediolateral x-rays were taken every 250 cycles and motion tracking was performed to determine movements at the arthrodesis site. Statistical analysis of the parameters of interest was performed at a level of significance p = 0.05. Results Displacement of the talo-navicular joint after 1000, 2000 and 4000 cycles was significantly lower for plantar plating (p≤0.039) while there was significantly less movement in the naviculo-cuneiform I joint for dorsal plating post these cycle numbers (p<0.001). Displacements in all three joints of the medial column, as well as angular and torsional deformations between the navicular and metatarsal I increased significantly for each plating technique between 1000, 2000 and 4000 cycles (p≤0.021). The two plating systems did not differ significantly with regard to stiffness and cycles to failure (p≥0.171). Conclusion From biomechanical point of view, although dorsomedial plating showed less movement than plantar plating in the current setup under dynamic loading, there was no significant difference between the two plating

  6. Nitrogen fixation apparatus

    DOEpatents

    Chen, Hao-Lin

    1984-01-01

    A method and apparatus for achieving nitrogen fixation includes a volumetric electric discharge chamber. The volumetric discharge chamber provides an even distribution of an electron beam, and enables the chamber to be maintained at a controlled energy to pressure (E/p) ratio. An E/p ratio of from 5 to 15 kV/atm of O.sub.2 /cm promotes the formation of vibrationally excited N.sub.2. Atomic oxygen interacts with vibrationally excited N.sub.2 at a much quicker rate than unexcited N.sub.2, greatly improving the rate at which NO is formed.

  7. Conversion from temporary external fixation to definitive fixation: shaft fractures.

    PubMed

    Dougherty, Paul J; Silverton, Craig; Yeni, Yener; Tashman, Scott; Weir, Robb

    2006-01-01

    Temporary external fixation is the most common method of initial stabilization of diaphyseal fractures in forward surgical hospitals. Once the patient arrives at a stable environment, usually the United States, the fracture is managed with intramedullary nailing, small-pin external fixation, or a modified external fixator. Future research should be directed toward improving methods of care. It is not precisely known when is the best time to convert to definitive fixation without increasing the risk of infection. The risk factors leading to infection and nonunion are not well-established, making that determination even more difficult. Clinical studies of a suitable size should provide insight into these problems. Although temporary external fixation is commonly used, an optimal construct has not been determined. Data from studies of in vivo fracture-site motion after application of the temporary external fixator should be compared with biomechanical testing of similar constructs. These data could be used to recommend optimal temporary external fixation constructs of tibia, femur, and humerus fractures using currently available devices as well as to provide groundwork for the next generation of fixators.

  8. Circular External Fixation as a Primary or Adjunctive Therapy for the Podoplastic Approach of the Diabetic Charcot Foot.

    PubMed

    Short, Daniel J; Zgonis, Thomas

    2017-01-01

    Numerous techniques have been described for surgical management of the diabetic Charcot foot. External fixation has become a main surgical tool for the reconstructive foot and ankle surgeon when dealing with the ulcerated diabetic Charcot foot. In the presence of an open wound and/or osteomyelitis, staged reconstruction with circular external fixation becomes ideal for salvage of the diabetic lower extremity. Also, circular external fixation can provide simultaneous compression and stabilization, correct the underlying osseous or soft tissue deformities, and surgically offload the diabetic Charcot foot. This article describes a variety of circular external fixation applications for the diabetic Charcot foot.

  9. Mechanical evaluation of external skeletal fixator-intramedullary pin tie-in configurations applied to cadaveral humeri from red-tailed hawks (Buteo jamaicensis).

    PubMed

    Van Wettere, Arnaud J; Redig, Patrick T; Wallace, Larry J; Bourgeault, Craig A; Bechtold, Joan E

    2009-12-01

    Use of external skeletal fixator-intramedullary pin (ESF-IM) tie-in fixators is an adjustable and effective method of fracture fixation in birds. The objective of this study was to determine the contribution of each of the following parameters to the compressive and torsional rigidity of an ESF-IM pin tie-in applied to avian bones with an osteotomy gap: (1) varying the fixation pin position in the proximal bone segment and (2) increasing the number of fixation pins in one or both bone segments. ESF-IM pin tie-in constructs were applied to humeri harvested from red-tailed hawks (Buteo jamaicensis) (n=24) that had been euthanatized for clinical reasons. Constructs with a variation in the placement of the proximal fixation pin and with 2, 3, or 4 fixation pins applied to avian bone with an osteotomy gap were loaded to a defined displacement in torque and axial compression. Response variables were determined from resulting load-displacement curves (construct stiffness, load at 1-mm displacement). Increasing the number of fixation pins from 1 to 2 per bone segment significantly increased the stiffness in torque (110%) and compression (60%), and the safe load in torque (107%) and compression (50%). Adding a fixation pin to the distal bone segment to form a 3-pin fixator significantly increased the stiffness (27%) and safe load (20%) in torque but not in axial compression. In the configuration with 2 fixation pins, placing the proximal pin distally in the proximal bone segment significantly increased the stiffness in torque (28%), and the safe load in torque (23%) and in axial compression (32%). Results quantified the relative importance of specific parameters affecting the rigidity of ESF-IM pin tie-in constructs as applied to unstable bone fracture models in birds.

  10. Arthrodesis tarsocrural or tarsometatarsal in 2 dogs using circular external skeletal fixator

    PubMed Central

    Rahal, Sheila C.; Volpi, Reinaldo S.; Hette, Khadije; Teixeira Neto, Francisco J.; Vulcano, Luiz C.

    2006-01-01

    An external fixation technique, using a circular fixator, to obtain arthrodesis was evaluated in 2 dogs with infected open lesions and soft tissue damage. In both cases, articular cartilage was curetted, and devitalized bone and necrotic soft tissue were removed. No bone graft was used. The wounds were maintained open and the dogs received postoperative antibiotic therapy. The arthrodesis site was compressed progressively as needed. Infection was eradicated and bony union was obtained in both dogs. It was concluded that the use of a circular fixator is an effective method to achieve arthrodesis. PMID:17017656

  11. Dynamic Simulations of Cancellous Bone Resorption Around Orthopaedic Fixative Implants

    DTIC Science & Technology

    2007-11-02

    surrounding bone , and, thereby, alleviate commonly observed conditions of loosening and failure of plate fixations due to stress shielding [1], [2]. II...axisymmetrical model of a bone cylinder with an outer cortical surface and an inner trabecular bulk (Fig. 1). A screw is inserted perpendicularly to the bone ...adaptation. Fig. 1. The idealized axisymmetrical model of a bone cylinder with an outer cortical surface and an inner trabecular bulk. The finite

  12. Outcomes of Internal Fixation in a Combat Environment

    DTIC Science & Technology

    2010-01-01

    A variety of internal fixation procedures were performed to include 44 plate and/or screw (88%), four intramedullary nail (8%), and two tension band...that underwent intramedullary nailing at an Air Force Theater Hospital in Balad, Iraq. Two-thirds of the patients had high-energy ballistic injuries...JOURNAL OF SURGICAL ORTHOPAEDIC ADVANCES 5. Keeney, J. A., Ingari, J. V., Mentzer, K. D., et al. Closed intramedullary nailing of femoral shaft fractures

  13. Eighth international congress on nitrogen fixation

    SciTech Connect

    Not Available

    1990-01-01

    This volume contains the proceedings of the Eighth International Congress on Nitrogen Fixation held May 20--26, 1990 in Knoxville, Tennessee. The volume contains abstracts of individual presentations. Sessions were entitled Recent Advances in the Chemistry of Nitrogen Fixation, Plant-microbe Interactions, Limiting Factors of Nitrogen Fixation, Nitrogen Fixation and the Environment, Bacterial Systems, Nitrogen Fixation in Agriculture and Industry, Plant Function, and Nitrogen Fixation and Evolution.

  14. Open reduction internal fixation for proximal humerus fractures indications, techniques, and pitfalls.

    PubMed

    Shulman, Brandon S; Egol, Kenneth A

    2013-01-01

    Proximal humerus fractures account for approximately 5% of all fractures. It is estimated that due to our aging population, orthopaedic surgeons will see a three-fold increase in proximal humerus fractures over the next 30 years. Internal fixation with locked plating is the current mainstay of treatment for functionally active patients who desire minimal loss of function. A thorough understanding of the indications, techniques, and drawbacks of treatment with internal fixation is essential to achieve the highest quality of patient care.

  15. Retrograde Tibial Nailing: a minimally invasive and biomechanically superior alternative to angle-stable plate osteosynthesis in distal tibia fractures

    PubMed Central

    2014-01-01

    Background Currently, antegrade intramedullary nailing and minimally invasive plate osteosynthesis (MIPO) represent the main surgical alternatives in distal tibial fractures. However, neither choice is optimal for all bony and soft tissue injuries. The Retrograde Tibial Nail (RTN) is a small-caliber prototype implant, which is introduced through a 2-cm-long incision at the tip of the medial malleolus with stab incisions sufficient for interlocking. During this project, we investigated the feasibility of retrograde tibial nailing in a cadaver model and conducted biomechanical testing. Methods Anatomical implantations of the RTN were carried out in AO/OTA 43 A1-3 fracture types in three cadaveric lower limbs. Biomechanical testing was conducted in an AO/OTA 43 A3 fracture model for extra-axial compression, torsion, and destructive extra-axial compression. Sixteen composite tibiae were used to compare the RTN against an angle-stable plate osteosynthesis (Medial Distal Tibial Plate, Synthes®). Statistical analysis was performed by Student's t test. Results Retrograde intramedullary nailing is feasible in simple fracture types by closed manual reduction and percutaneous reduction forceps, while in highly comminuted fractures, the use of a large distractor can aid the reduction. Biomechanical testing shows a statistically superior stability (p < 0.001) of the RTN during non-destructive axial loading and torsion. Destructive extra-axial compression testing resulted in failure of all plate constructs, while all RTN specimens survived the maximal load of 1,200 N. Conclusions The prototype retrograde tibial nail meets the requirements of maximum soft tissue protection by a minimally invasive surgical approach with the ability of secure fracture fixation by multiple locking options. Retrograde tibial nailing with the RTN is a promising concept in the treatment of distal tibia fractures. PMID:24886667

  16. Finite element evaluation of three methods of stable fixation of condyle base fractures.

    PubMed

    de Jesus, G P; Vaz, L G; Gabrielli, M F R; Passeri, L A; V Oliveira, T; Noritomi, P Y; Jürgens, P

    2014-10-01

    The surgical treatment of mandibular condyle fractures currently offers several possibilities for stable internal fixation. In this study, a finite element model evaluation was performed of three different methods for osteosynthesis of low subcondylar fractures: (1) two four-hole straight plates, (2) one seven-hole lambda plate, and (3) one four-hole trapezoidal plate. The finite element model evaluation considered a load applied to the first molar on the contralateral side to the fracture. Results showed that, although the three methods are capable of withstanding functional loading, the lambda plate displayed a more homogeneous stress distribution for both osteosynthesis material and bone and may be a better method when single-plate fixation is the option.

  17. Effect of cortical thickness and cancellous bone density on the holding strength of internal fixator screws.

    PubMed

    Seebeck, J; Goldhahn, J; Städele, H; Messmer, P; Morlock, M M; Schneider, E

    2004-11-01

    Internal fixators are a new class of implants designed to preserve the periosteal blood supply of the bone. In contrast to conventional plate fixation in which the screws have spherical heads and are loaded mainly by axial pullout forces, screws in internal fixators are "locked" within the plate and therefore subjected to axial as well as bending loads. In this study the ultimate loads of screws of a commercially available internal fixator system were tested in a pullout (n = 72) and cantilever bending mode (n = 72) in metaphyseal and diaphyseal regions of four pairs of human tibiae with different bone qualities. Cortical thickness and cancellous bone density were determined at the screw insertion sites. Stepwise multiple linear regression revealed that cortical thickness and cancellous density can explain 93% and 98% of the variance of the ultimate load of the screws in an axial pullout and cantilever bending mode. Screws in internal fixators are better suited to transmit shear forces and thereby make better use of the strength potential of bone than screws used in conventional plate fixation: this is especially advantageous when bone strength is reduced, e.g. due to osteoporosis.

  18. Modeling and minimizing interference from corneal birefringence in retinal birefringence scanning for foveal fixation detection.

    PubMed

    Irsch, Kristina; Gramatikov, Boris; Wu, Yi-Kai; Guyton, David

    2011-07-01

    Utilizing the measured corneal birefringence from a data set of 150 eyes of 75 human subjects, an algorithm and related computer program, based on Müller-Stokes matrix calculus, were developed in MATLAB for assessing the influence of corneal birefringence on retinal birefringence scanning (RBS) and for converging upon an optical/mechanical design using wave plates ("wave-plate-enhanced RBS") that allows foveal fixation detection essentially independently of corneal birefringence. The RBS computer model, and in particular the optimization algorithm, were verified with experimental human data using an available monocular RBS-based eye fixation monitor. Fixation detection using wave-plate-enhanced RBS is adaptable to less cooperative subjects, including young children at risk for developing amblyopia.

  19. Extracapsular hip fractures: fixation with a twin hook or a lag screw?

    PubMed

    Olsson, O; Ceder, L; Lunsjö, K; Hauggaard, A

    2000-01-01

    The twin hook, which has 2 oppositely directed apical hooks, is an alternative to the lag screw for use with a 'dynamic plate' in the fixation of trochanteric hip fractures. In this prospective study lasting 1 year, 102 consecutive patients with trochanteric hip fractures were treated by 19 surgeons with either a twin hook or a lag screw combined with a conventional sliding hip screw plate or a Medoff sliding plate. Seven intraoperative errors were made with the twin hook but postoperative migration did not differ significantly between the 2 groups. Postoperative fixation failures were equally distributed between the 2 groups. The twin hook provides adequate fixation, which is comparable to that produced by a lag screw.

  20. Modeling and minimizing interference from corneal birefringence in retinal birefringence scanning for foveal fixation detection

    PubMed Central

    Irsch, Kristina; Gramatikov, Boris; Wu, Yi-Kai; Guyton, David

    2011-01-01

    Utilizing the measured corneal birefringence from a data set of 150 eyes of 75 human subjects, an algorithm and related computer program, based on Müller-Stokes matrix calculus, were developed in MATLAB for assessing the influence of corneal birefringence on retinal birefringence scanning (RBS) and for converging upon an optical/mechanical design using wave plates (“wave-plate-enhanced RBS”) that allows foveal fixation detection essentially independently of corneal birefringence. The RBS computer model, and in particular the optimization algorithm, were verified with experimental human data using an available monocular RBS-based eye fixation monitor. Fixation detection using wave-plate-enhanced RBS is adaptable to less cooperative subjects, including young children at risk for developing amblyopia. PMID:21750772

  1. Instrumental fixation of the cervical spine with Ti-mesh prosthesis: a preliminary report.

    PubMed

    Kolasa, P; Boroński, K

    2000-06-30

    This article describes the surgical treatment of the fractured body of a cervical vertebra, using the Codman Ti-mesh prosthesis according to the Harms method. This male patient had suffered a multiple fracture of the C6 cervical body; he required decompression of the nerve elements of the vertebral canal by C6 corporectomy and C5-C7 intervertebral fixation. A Ti-mesh prosthesis was filled with bone fragments from the fractured vertebra. A Caspar plate manufactured by Codman was used for C5-C7 intervertebral fixation. The chief advantages of the method applied here include shortening the duration of surgery and providing good, quick fixation.

  2. A Novel Technique for Attaining Maxillomandibular Fixation in the Edentulous Mandible Fracture

    PubMed Central

    Knotts, Christopher; Workman, Meredith; Sawan, Kamal; El Amm, Christian

    2012-01-01

    Edentulous mandible fractures present a unique and challenging surgical problem, particularly because of lack of occlusive dental surfaces to capitalize upon maxillomandibular fixation (MMF). We present a novel technique to achieve MMF using rigid plates spanning the oral cavity to fixate the maxilla to the mandible. The process is rapid and allows stability using the established principles of rigidity, external fixation, and osteosynthesis. This technique allows for a faster MMF than with a Gunning splint and allows for easier oral hygiene. An illustrative case and pre- and postoperative imaging are provided. PMID:23449752

  3. A novel technique for attaining maxillomandibular fixation in the edentulous mandible fracture.

    PubMed

    Knotts, Christopher; Workman, Meredith; Sawan, Kamal; El Amm, Christian

    2012-03-01

    Edentulous mandible fractures present a unique and challenging surgical problem, particularly because of lack of occlusive dental surfaces to capitalize upon maxillomandibular fixation (MMF). We present a novel technique to achieve MMF using rigid plates spanning the oral cavity to fixate the maxilla to the mandible. The process is rapid and allows stability using the established principles of rigidity, external fixation, and osteosynthesis. This technique allows for a faster MMF than with a Gunning splint and allows for easier oral hygiene. An illustrative case and pre- and postoperative imaging are provided.

  4. Double-eyelid operation: orbicularis oculi-levator aponeurosis fixation technique.

    PubMed

    Park, Jung I; Park, Min S

    2007-08-01

    Incision techniques in the past focused on fixing the pretarsal skin to either the tarsal plate or to the levator aponeurosis. High relapse rate remains one of the main concerns in double-eyelid surgery. To address these issues, the author developed a pretarsal orbicularis oculi muscle-levator aponeurosis fixation technique. This technique results in better fixation between the skin and the levator aponeurosis by recruiting a bulky, pretarsal orbicularis oculi muscle in the fixation mechanism. This technique provides for a solidly fixed, tightly stretched pretarsal skin when the eyes are open with significantly reduced chances of relapse.

  5. Mechanical evaluation of transosseous wire rope configurations in a large animal external fixator.

    PubMed

    Rapoff, A J; Markel, M D; Vanderby, R

    1995-05-01

    By use of wire ropes as the transosseous component, an external skeletal fixator for the repair of long bone fractures in horses and cattle has been designed and tested in axial compression. Theoretical methods were used in the design process to size fixator components; however, our results suggest that conventional methods of analyzing the displacement of the transosseous component may not apply to wire ropes. Large pretensions in the wire ropes are necessary to obtain functional stiffnesses for fracture fixation. Therefore, a method was sought for terminating the ropes so that an appropriate pretension could be introduced into the rope through its interface with the fixator rings. Ropes were terminated by use of 5 methods and were tested in axial tension to failure. These methods included 3 copper sleeve arrangements, welded ends, and drum sockets. The drum sockets (57.6% of rope breaking strength) far exceeded the strengths provided by the copper sleeves (8.5 to 26.6%) and the welded ends (44.3%). Using the drum sockets, 5 rope configurations were assembled to the fixator, using wood blocks to simulate bones with a gap defect. The fixator was loaded in axial compression for each of the rope configurations, and stiffnesses were determined from measured axial displacement and applied load. The 4-ring fixator configuration, with 2 ropes at 60 degrees angular separation/ring, was the stiffest. In a worst case (gap) model, a mean axial compression load of 1,730 N was observed at 2 mm of displacement for a 4-ring fixator configuration.(ABSTRACT TRUNCATED AT 250 WORDS)

  6. Neuronal control of fixation and fixational eye movements

    PubMed Central

    2017-01-01

    Ocular fixation is a dynamic process that is actively controlled by many of the same brain structures involved in the control of eye movements, including the superior colliculus, cerebellum and reticular formation. In this article, we review several aspects of this active control. First, the decision to move the eyes not only depends on target-related signals from the peripheral visual field, but also on signals from the currently fixated target at the fovea, and involves mechanisms that are shared between saccades and smooth pursuit. Second, eye position during fixation is actively controlled and depends on bilateral activity in the superior colliculi and medio-posterior cerebellum; disruption of activity in these circuits causes systematic deviations in eye position during both fixation and smooth pursuit eye movements. Third, the eyes are not completely still during fixation but make continuous miniature movements, including ocular drift and microsaccades, which are controlled by the same neuronal mechanisms that generate larger saccades. Finally, fixational eye movements have large effects on visual perception. Ocular drift transforms the visual input in ways that increase spatial acuity; microsaccades not only improve vision by relocating the fovea but also cause momentary changes in vision analogous to those caused by larger saccades. This article is part of the themed issue ‘Movement suppression: brain mechanisms for stopping and stillness’. PMID:28242738

  7. Effect of wire tension on stiffness of tensioned fine wires in external fixation: a mechanical study.

    PubMed

    Antoci, Valentin; Voor, Michael J; Antoci, Valentin; Roberts, Craig S

    2007-09-01

    To determine the effect of changes in magnitude of transfixion wire tension on stiffness of fine-wire external-fixation load deformation, we compared results obtained with different wire tensions (50-140 kg) under identical conditions of central axial compression, medial compression-bending, posterior compression-bending, posteromedial compression-bending, and torsion. Stiffness values were calculated from the load-deformation and torque-angle curves. Tension of 140 kg provided the most stiffness, and there was a trend toward increasing overall stiffness with increasing wire tension. The 1.8-mm wires should be tensioned to at least 110 kg in most cases of fine-wire external fixation; compared with all tensions less than 110 kg, this tension provides significantly more mechanical stability in all loading modes.

  8. Biomechanical comparison of gourd-shaped LCP versus LCP for fixation of comminuted tibial shaft fracture.

    PubMed

    Xu, Guo-hui; Liu, Bo; Zhang, Qi; Wang, Juan; Chen, Wei; Liu, Yue-ju; Peng, A-qin; Zhang, Ying-ze

    2013-04-01

    The purpose of this study was to compare monotonic biomechanical properties of gourd-shaped LCP fixation with LCP fixation of human tibial shaft in gap fracture mode. Twenty paired fresh cadaveric human tibias were randomly divided into 4 groups (5 pairs each): (1) axial loading single cycle to failure testing, (2) torsion single cycle to failure testing, (3) 4-point bending single cycle to failure testing, and (4) dynamic 4-point bending testing. A 7-hole 4.5 mm gourd-shaped LCP was secured on the anteromedial surface of 1 randomly selected bone from each pair, respectively, using 6 locking screws in the 1st, 2nd, 3rd, 5th, 6th and 7th hole with the middle hole unfilled and just located at the mid-diaphysis of the tibia. A 7-hole 4.5 mm LCP was secured on the other bone with the same method. Standard AO/ASIF techniques were used. After fixation finished, a 10 mm gap in the mid-diaphysis of tibia was created, centrally located at the unfilled hole. The axial, torsional, and bending stiffness and failure strengths were calculated from the collected data in static testings and statistically compared using paired Student's t-test. The 4-point bending fatigue lives of the two constructs were calculated from the dynamic testing data and also statistically compared using paired Student's t-test. Failure modes were recorded and visually analyzed. P<0.05 was considered significant. Results showed that the axial, torsional and bending stiffness of gourd-shaped LCP construct was greater (4%, 19%, 12%, respectively, P<0.05) than that of the LCP construct, and the axial, torsional and bending failure strengths of gourd-shaped LCP construct were stronger (10%, 46%, 29%, respectively, P<0.05) than those of the LCP construct. Both constructs failed as a result of plate plastic torsional deformation. After axial loading and 4-point bending testings, LCP failed in term of an obvious deformation of bent apex just at the unfilled plate hole, while the gourd-shaped LCP failed in term

  9. Diaphyseal Fractures of the Forearm in Adults, Plating Or Intramedullary Nailing Is a Better Option for the Treatment?

    PubMed Central

    Al-Sadek, Tabet A.; Niklev, Desislav; Al-Sadek, Ahmed

    2016-01-01

    BACKGROUND: Fractures of the radius and ulna occupy a large field of the modern traumatology. Therefore, these fractures are a major subject in modern orthopaedics and traumatology. The study of the mechanisms of the trauma, and the pathophysiological changes that occur are of great importance for the development of ever more efficient and varied ways of the treatment and prophylactics of this type of fracture. AIM: The aim of this paper was to study the pattern of the diaphyseal fractures of the forearm in adults, to decide the modalities of surgical management, to observe the period of fracture healing clinically and radiologically, as well to study the rehabilitation of the patients. MATERIAL AND METHODS: The present study included 45 cases of diaphyseal fractures of both bones forearm in adults presenting to the orthopaedic outpatient department. For all the patients a detailed history was taken. A thorough clinical examination was carried out, required X-rays were taken, and initial treatment was given and admitted as in all patients. After careful pre-operative planning and evaluation for anaesthetic fitness, patients were operated for the fractures of both bone forearms. Twenty-three cases with 46 fractures were treated by open reduction and rigid fixation with DCP & Semi-tubular plates and 22 cases with 44 fractures were treated by closed reduction and fixation with “Talwarkar” intramedullary square nails. RESULTS: United results were found in 100% of plating group vs. 86% in the nailing group. Delayed and non-union results were found in 9% of the nailing group only. Average time to union in weeks was 9.4 weeks in the plating group vs. 10.2 weeks in the nailing group. CONCLUSION: Open reduction and internal fixation with compression plates with strict adherence to surgical technique is the gold standard method of treatment in both bones forearm fractures with excellent results than closed reduction, internal fixation with “Talwarkar” square nails

  10. Internal fixation: a historical review.

    PubMed

    Greenhagen, Robert M; Johnson, Adam R; Joseph, Alison

    2011-08-01

    Internal fixation has become a pillar of surgical specialties, yet the evolution of these devices has been relatively short. The first known description of medical management of a fracture was found in the Edwin Smith Papyrus of Ancient Egypt (circa 2600 bc). The first description of internal fixation in the medical literature was in the 18th century. The advancement of techniques and technology over the last 150 years has helped to preserve both life and function. The pace of advancement continues to accelerate as surgeons continue to seek new technology for osseous fixation. The authors present a thorough review of the history of internal fixation and the transformation into a multibillion dollar industry.

  11. Molecular Biology of Nitrogen Fixation

    ERIC Educational Resources Information Center

    Shanmugam, K. T.; Valentine, Raymond C.

    1975-01-01

    Reports that as a result of our increasing knowledge of the molecular biology of nitrogen fixation it might eventually be possible to increase the biological production of nitrogenous fertilizer from atmospheric nitrogen. (GS)

  12. Peen plating

    NASA Technical Reports Server (NTRS)

    Babecki, A. J. (Inventor); Haehner, C. L.

    1973-01-01

    A process for metal plating which comprises spraying a mixture of metallic powder and small peening particles at high velocity against a surface is described. The velocity must be sufficient to impact and bond metallic powder onto the surface. In the case of metal surfaces, the process has as one of its advantages providing mechanical working (hardening) of the surface simultaneously with the metal plating.

  13. Compression stockings

    MedlinePlus

    ... knee bend. Compression Stockings Can Be Hard to Put on If it's hard for you to put on the stockings, try these tips: Apply lotion ... your legs, but let it dry before you put on the stockings. Use a little baby powder ...

  14. The pathologist's guide to fixatives.

    PubMed

    Qidwai, Kiran; Afkhami, Michelle; Day, Christina E

    2014-01-01

    Proper tissue fixation is essential to ensure the highest level of specimen evaluation. Pathologists and laboratory staff are frequently consulted by clinical counterparts regarding what fixative should be used for different tissues or to enable a diagnosis of a specific condition. It is vital for the patient that the pathologist provides accurate information to ensure proper fixation. Frequently, once a tissue has been fixed inadequately or inappropriately, remedial changes may no longer be possible. Most often formalin is an adequate choice, if not the optimal one; however, there are certain situations when placing the tissue in formalin may limit the ability to reach a definitive diagnosis. It is imperative for pathologists to have the knowledge to communicate which fixative is optimal. Furthermore, as we move into a world of personalized medicine, where ancillary testing has both diagnostic and specific therapeutic implications, knowledge about how different fixatives affect immunohistochemistry, cytogenetics, and molecular studies becomes even more significant. This chapter provides practical information regarding common fixatives, their mechanism of action and optimal uses.

  15. Biomechanics of external fixation and limb lengthening.

    PubMed

    Younger, Alastair S E; Morrison, James; MacKenzie, William G

    2004-09-01

    Surgeons who use external fixators for foot and ankle conditions need to understand the biomechanical principles to ensure good outcomes. Fixators can be used for fracture fixation, correction of contractures, distraction osteogenesis, and distraction arthroplasty. A two-ring fixator with wire fixation remains the gold standard with which all other frames are compared. Small changes in mechanical characteristics can have major implications on new bone or cartilage formation.

  16. Effects of fixatives on function of pulmonary surfactant.

    PubMed

    Bachofen, H; Gerber, U; Schürch, S

    2002-09-01

    The structure of pulmonary surfactant films remains ill defined. Although plausible film fragments have been imaged by electron microscopy, questions about the significance of the findings and even about the true fixability of surfactant films by the usual fixatives glutaraldehyde (GA), osmium tetroxide (OsO(4)), and uranyl acetate (UA) have not been settled. We exposed functioning natural surfactant films to fixatives within a captive bubble surfactometer and analyzed the effect of fixatives on surfactant function. The capacity of surfactant to reach near-zero minimum surface tension on film compression was barely impaired after exposure to GA or OsO(4). Although neither GA nor OsO(4) prevented the surfactant from forming a surface active film, GA increased the equilibrium surface tension to above 30 mN/m, and both GA and OsO(4) decreased film stability as seen in the slowly rising minimum surface tension from 1 to ~5 mN/m in 10 min. In contrast, the effect of UA seriously impaired surface activity in that both adsorption and minimum surface tension were substantially increased. In conclusion, the fixatives tested in this study are not suitable to fix, i.e., to solidify, surfactant films. Evidently, however, OsO(4) and UA may serve as staining agents.

  17. Statistical tests of additional plate boundaries from plate motion inversions

    NASA Technical Reports Server (NTRS)

    Stein, S.; Gordon, R. G.

    1984-01-01

    The application of the F-ratio test, a standard statistical technique, to the results of relative plate motion inversions has been investigated. The method tests whether the improvement in fit of the model to the data resulting from the addition of another plate to the model is greater than that expected purely by chance. This approach appears to be useful in determining whether additional plate boundaries are justified. Previous results have been confirmed favoring separate North American and South American plates with a boundary located beween 30 N and the equator. Using Chase's global relative motion data, it is shown that in addition to separate West African and Somalian plates, separate West Indian and Australian plates, with a best-fitting boundary between 70 E and 90 E, can be resolved. These results are generally consistent with the observation that the Indian plate's internal deformation extends somewhat westward of the Ninetyeast Ridge. The relative motion pole is similar to Minster and Jordan's and predicts the NW-SE compression observed in earthquake mechanisms near the Ninetyeast Ridge.

  18. Nitrogen Fixation (Acetylene Reduction) Associated with Duckweed (Lemnaceae) Mats

    PubMed Central

    Zuberer, D. A.

    1982-01-01

    Duckweed (Lemnaceae) mats in Texas and Florida were investigated, using the acetylene reduction assay, to determine whether nitrogen fixation occurred in these floating aquatic macrophyte communities. N2-fixing microorganisms were enumerated by plating or most-probable-number techniques, using appropriate N-free media. Results of the investigations indicated that substantial N2-fixation (C2H2) was associated with duckweed mats in Texas and Florida. Acetylene reduction values ranged from 1 to 18 μmol of C2H4 g (dry weight)−1 day−1 for samples incubated aerobically in light. Dark N2 fixation was always two- to fivefold lower. 3-(3,4-Dichlorophenyl)-1,1-dimethylurea (7 to 10 μM) reduced acetylene reduction to levels intermediate between light and dark incubation. Acetylene reduction was generally greatest for samples incubated anaerobically in the light. It was estimated that 15 to 20% of the N requirement of the duckweed could be supplied through biological nitrogen fixation. N2-fixing heterotrophic bacteria (105 cells g [wet weight]−1 and cyanobacteria (105 propagules g [wet weight]−1 were associated with the duckweed mats. Azotobacter sp. was not detected in these investigations. One diazotrophic isolate was classified as Klebsiella. PMID:16345992

  19. Fuel cell separator plate with bellows-type sealing flanges

    SciTech Connect

    Louis, George A.

    1986-08-05

    A fuel cell separator includes a rectangular flat plate having two unitary upper sealing flanges respectively comprising opposite marginal edges of the plate folded upwardly and back on themselves and two lower sealing flanges respectively comprising the other two marginal edges of the plate folded downwardly and back on themselves. Each of the sealing flanges includes a flat wall spaced from the plate and substantially parallel thereto and two accordion-pleated side walls, one of which interconnects the flat wall with the plate and the other of which stops just short of the plate, these side walls affording resilient compressibility to the sealing flange in a directiongenerally normal to the plane of the plate. Four corner members close the ends of the sealing flanges. An additional resiliently compressible reinforcing member may be inserted in the passages formed by each of the sealing flanges with the plate.

  20. Fuel cell separator plate with bellows-type sealing flanges

    DOEpatents

    Louis, G.A.

    1984-05-29

    A fuel cell separator includes a rectangular flat plate having two unitary upper sealing flanges respectively comprising opposite marginal edges of the plate folded upwardly and back on themselves and two lower sealing flanges respectively comprising the other two marginal edges of the plate folded downwardly and back on themselves. Each of the sealing flanges includes a flat wall spaced from the plate and substantially parallel thereto and two accordion-pleated side walls, one of which interconnects the flat wall with the plate and the other of which steps just short of the plate, these side walls affording resilient compressibility to the sealing flange in a direction generally normal to the plane of the plate. Four corner members close the ends of the sealing flanges. An additional resiliently compressible reinforcing member may be inserted in the passages formed by each of the sealing flanges with the plate.

  1. Use of orthogonal or parallel plating techniques to treat distal humerus fractures.

    PubMed

    Abzug, Joshua M; Dantuluri, Phani K

    2010-08-01

    Distal humerus fractures continue to be a complex fracture to treat. This article describes two surgical techniques that can be used to tackle these difficult fractures: Parallel plating and orthogonal plating. Both techniques have yielded excellent outcomes after open reduction and internal fixation; yet each has its own set of unique considerations. However, the key to successful treatment of these difficult fractures regardless of technique remains obtaining anatomic reduction with stable fixation and the implementation of early motion.

  2. Anomalous Buckling Characteristics of Laminated Metal-Matrix Composite Plates with Central Square Holes

    NASA Technical Reports Server (NTRS)

    Ko, William L.

    1998-01-01

    Compressive buckling analysis was performed on metal-matrix composite (MMC) plates with central square holes. The MMC plates have varying aspect ratios and hole sizes and are supported under different boundary conditions. The finite-element structural analysis method was used to study the effects of plate boundary conditions, plate aspect ratio, hole size, and the composite stacking sequence on the compressive buckling strengths of the perforated MMC plates. Studies show that by increasing the hole sizes, compressive buckling strengths of the perforated MMC plates could be considerably increased under certain boundary conditions and aspect ratios ("anomalous" buckling behavior); and that the plate buckling mode could be symmetrical or antisymmetrical, depending on the plate boundary conditions, aspect ratio, and the hole size. For same-sized plates with same-sized holes, the compressive buckling strengths of the perforated MMC plates with [90/0/0/90]2 lamination could be as much as 10 percent higher or lower than those of the [45/- 45/- 45/45]2 laminations, depending on the plate boundary conditions, plate aspect ratios, and the hole size. Clamping the plate edges induces far stronger "anomalous" buckling behavior (enhancing compressive buckling strengths at increasing hole sizes) of the perforated MMC plates than simply supporting the plate edges.

  3. Interdigitated craniotomy: a simple technique to fix a bone flap with only a single plate.

    PubMed

    Takahashi, Noboru; Fujiwara, Kazunori; Saito, Keiichi; Tominaga, Teiji

    2015-10-01

    In pterional craniotomy, fixation plates cause artifacts on postoperative radiological images; furthermore, they often disfigure the scalp in hairless areas. The authors describe a simple technique to fix a cranial bone flap with only a single plate underneath the temporalis muscle in an area with hair, rather than using a plate in a hairless area. The key to this technique is to cut the anterior site of the bone flap at alternate angles on the cut surface. Interdigitation between the bone flap and skull enables single-plate fixation in the area with hair, which reduces artifacts on postoperative radiological images and provides excellent postoperative cosmetic results.

  4. Elastically suspending the screw holes of a locked osteosynthesis plate can dampen impact loads.

    PubMed

    Capanni, Felix; Hansen, Kirk; Fitzpatrick, Daniel C; Madey, Steven M; Bottlang, Michael

    2015-06-01

    Impact damping by elastic fixation is a principal engineering strategy to increase the durability of load-bearing structures exposed to prolonged dynamic loading. This biomechanical study evaluated axial impact damping provided by a novel dynamic locking plate. In this design, locking screw holes are elastically suspended within a silicone envelope inside the locking plate. Axial impact damping was assessed for 3 distinct fixation constructs applied to bridge a 10-mm fracture gap of a femoral diaphysis surrogate: a standard locking plate, a dynamic locking plate, and an Ilizarov ring fixator. First, the 3 fixation constructs were characterized by determining their axial stiffness. Subsequently, constructs were subjected to a range of axial impact loads to quantify damping of force transmission. Compared with standard locked plating constructs, dynamic plating constructs were 58% less stiff (P < .01) and Ilizarov constructs were 88% less stiff (P < .01). Impact damping correlated inversely with construct stiffness. Compared with standard plating, dynamic plating constructs and Ilizarov constructs dampened the transmission of impact loads by up to 48% (P < .01) and 74% (P < .01), respectively. In conclusion, lower construct stiffness correlated with superior damping of axial impact loads. Dynamic locking plates provide significantly greater impact damping compared with standard locking plates.

  5. A new adhesive technique for internal fixation in midfacial surgery

    PubMed Central

    Endres, Kira; Marx, Rudolf; Tinschert, Joachim; Wirtz, Dieter Christian; Stoll, Christian; Riediger, Dieter; Smeets, Ralf

    2008-01-01

    Background The current surgical therapy of midfacial fractures involves internal fixation in which bone fragments are fixed in their anatomical positions with osteosynthesis plates and corresponding screws until bone healing is complete. This often causes new fractures to fragile bones while drilling pilot holes or trying to insert screws. The adhesive fixation of osteosynthesis plates using PMMA bone cement could offer a viable alternative for fixing the plates without screws. In order to achieve the adhesive bonding of bone cement to cortical bone in the viscerocranium, an amphiphilic bone bonding agent was created, analogous to the dentin bonding agents currently on the market. Methods The adhesive bonding strengths were measured using tension tests. For this, metal plates with 2.0 mm diameter screw holes were cemented with PMMA bone cement to cortical bovine bone samples from the femur diaphysis. The bone was conditioned with an amphiphilic bone bonding agent prior to cementing. The samples were stored for 1 to 42 days at 37 degrees C, either moist or completely submerged in an isotonic NaCl-solution, and then subjected to the tension tests. Results Without the bone bonding agent, the bonding strength was close to zero (0.2 MPa). Primary stability with bone bonding agent is considered to be at ca. 8 MPa. Moist storage over 42 days resulted in decreased adhesion forces of ca. 6 MPa. Wet storage resulted in relatively constant bonding strengths of ca. 8 MPa. Conclusion A new amphiphilic bone bonding agent was developed, which builds an optimizied interlayer between the hydrophilic bone surface and the hydrophobic PMMA bone cement and thus leads to adhesive bonding between them. Our in vitro investigations demonstrated the adhesive bonding of PMMA bone cement to cortical bone, which was also stable against hydrolysis. The newly developed adhesive fixing technique could be applied clinically when the fixation of osteosynthesis plates with screws is impossible. With

  6. Biomechanical evaluation of three ventral fixation methods for canine atlantoaxial instability: a cadaveric study

    PubMed Central

    TAKAHASHI, Fumitaka; HAKOZAKI, Takaharu; KANNO, Nobuo; HARADA, Yasuji; YAMAGUCHI, Shinya; HARA, Yasushi

    2016-01-01

    We evaluated comparatively the mechanical strength in three kinds of surgical fixation techniques for canine atlantoaxial joint. Atlantoaxial plate fixation (APF), polymethylmethacrylate (PMMA) fixation (PMF) and transarticular fixation (TAF) were applied to the atlas and axis harvested from healthy beagle dogs, and then, the specimens were tested. The PMF group had significantly higher resistance to flexion than the APF group (P=0.030) and the TAF group (P=0.004). There were no significant differences in resistance to torsion between the APF group and the PMF group, while the APF group had significantly higher resistance to torsion than the TAF group (P=0.037). Considering the possible drawbacks of using PMMA, the APF method is proposed as an alternative to the PMF method. PMID:27593982

  7. Plate on plate osteosynthesis for the treatment of nonhealed periplate fractures.

    PubMed

    Arealis, Georgios; Nikolaou, Vassilios S; Lacon, Andrew; Ashwood, Neil; Hamlet, Mark

    2014-01-01

    Purpose. The purpose of this paper is to present our technique for the treatment of periplate fractures. Methods. From 2009 to 2012 we treated three patients. In all cases the existing plate was left and the new one placed over the existing. Locking screws were placed through both plates. The other screws in the new plate were used as best suited the fracture. Results. In all cases less than 6 months had passed between fractures. None of the original fractures had healed. Mean followup was 2 years. All fractures proceeded to union within 7 months. No complications were recorded. All the patients returned to their normal activities and were satisfied with the results of their treatment. Conclusion. Our plate on plate technique is effective for the treatment of periplate fractures. A solid fusion can be achieved at the new fracture site without disturbing the previous fixation.

  8. An intermaxillary fixation screw traction wire: an aid for facial bone fracture repair.

    PubMed

    Kim, Myung-Good; Yoo, Roh-Eul; Chang, Hak; Kwon, Sung-Tack; Baek, Rong-Min; Minn, Kyung-Won

    2009-07-01

    We have devised a new technique to improve stabilization of fractured facial bone fractures (frontal sinus fractures, zygomatic fractures, mandibular condyle fractures) by intermaxillary fixation screw traction wires (stainless steel wires through intermaxillary fixation screws). A retrospective study evaluating intermaxillary fixation screw traction wires was performed. We have used this technique for 3 cases of frontal sinus fractures, 9 cases of zygomatic fractures, and 7 cases of mandibular condyle fractures. After dissection of a fractured site, a hole is drilled on the fractured bone where it does not interfere with positioning the plate across the fracture line. After an intermaxillary fixation screw is inserted, a stainless steel wire is tied through a hole in the screw head. By the aid of wire for traction, the displaced fractured bone is easily aligned to the proper position. Plates and screws are applied readily on the predetermined area. A retrospective study on 19 patients using intermaxillary fixation screw traction wires was performed. The diagnoses and associated complications of the cases were recorded. No associated complication as a result of using this technique was identified. The use of intermaxillary fixation screw traction wire enhances stabilization and visualization without possible risk for surrounding soft tissue injury using, a sharp traction device like a bone hook. An intermaxillary fixation screw traction wire is an useful aid for visualization and stabilization during facial bone fracture reduction, particularly where exposure is difficult such as in the condylar region of the mandible. And unlike a classic traction wire, the intermaxillary fixation screw traction wire has almost no risk of having it loosened from the screw.

  9. Expression of TGF-β in Fractures Fixed by Nitinol Swan-like Memory Compressive Connectors

    NASA Astrophysics Data System (ADS)

    Li, M.; Zhang, C. C.; Xu, S. G.; Fu, Q. G.

    2011-07-01

    In this article, the effect of internal fixation of a Nitinol swan-like memory compressive connector (SMC) on the temporal expression of transforming growth factor-β (TGF-β) at fracture sites is evaluated. Specimens were collected from 35 New Zealand rabbits modeled for bilateral humeral fracture fixed with either SMC or stainless dynamic compression plate (DCP). Five rabbits each were killed at day 1, 3, 7, 14, 21, 28, and 56. The local positive staining potency, positive area ratio, and positive index of TGF-β were measured using an immunohistochemistry approach (EnVision) in combination with a computerized image analysis system. TGF-β staining was seen in mesenchymal cells, osteoblasts, chondrocytes, and in the extracellular matrix of fractures fixed in both the SMC and the DCP samples without a significant difference in staining at both the early stages (days 1 and 3) and day 56. A higher TGF-β content was observed in the fractures fixed with SMC when compared to that of DCP from day 7 to 28. As a conclusion, TGF-β is highly expressed in fractures fixed with SMC during chondrogenesis stage and entochondrostosis stage. Finally, the mechanism of how SMC promoting synthesis and secretion of TGF-β in the process of fracture healing has been discussed.

  10. Use of a posterior antiglide plate in a pediatric ankle fracture: a case report.

    PubMed

    Fleming, Justin J; Kooner, Rajdeep K; Soondar, Stephen

    2009-01-01

    The authors describe the case of a 13-year-old male with a Salter-Harris II fracture-subluxation of the fibula. Open reduction and internal fixation with a posterior antiglide plate achieved mortise stability and avoided penetration of the fibular physis by fixation devices. After searching the Medline, EMBASE, CINAHL, and the Cochrane Library databases, to our knowledge, there have been no published reports describing the advantages associated with the use of a posterior antiglide plate for fixation of the immature fibula.

  11. Dynamic-Range Compression For Infrared Imagery

    NASA Technical Reports Server (NTRS)

    Cheng, Li-Jen; Liu, Hua-Kuang

    1989-01-01

    Photorefractive crystals covering detectors prevent saturation. To make full use of information in image, desirable to compress dynamic range of input intensity to within region of approximately linear response of detector. Dynamic-range compression exhibited by measurements of attenuation in photorefractive GaAs. Effective dynamic-range-compressor plate, film, or coating reduces apparent contrast of scene imaged on detector plane to within dynamic range of detectors; original image contrast or intensity data recovered subsequently in electronic image processing because range-compression function and inverse known.

  12. Compressed convolution

    NASA Astrophysics Data System (ADS)

    Elsner, Franz; Wandelt, Benjamin D.

    2014-01-01

    We introduce the concept of compressed convolution, a technique to convolve a given data set with a large number of non-orthogonal kernels. In typical applications our technique drastically reduces the effective number of computations. The new method is applicable to convolutions with symmetric and asymmetric kernels and can be easily controlled for an optimal trade-off between speed and accuracy. It is based on linear compression of the collection of kernels into a small number of coefficients in an optimal eigenbasis. The final result can then be decompressed in constant time for each desired convolved output. The method is fully general and suitable for a wide variety of problems. We give explicit examples in the context of simulation challenges for upcoming multi-kilo-detector cosmic microwave background (CMB) missions. For a CMB experiment with detectors with similar beam properties, we demonstrate that the algorithm can decrease the costs of beam convolution by two to three orders of magnitude with negligible loss of accuracy. Likewise, it has the potential to allow the reduction of disk space required to store signal simulations by a similar amount. Applications in other areas of astrophysics and beyond are optimal searches for a large number of templates in noisy data, e.g. from a parametrized family of gravitational wave templates; or calculating convolutions with highly overcomplete wavelet dictionaries, e.g. in methods designed to uncover sparse signal representations.

  13. Mini external fixation in the hand.

    PubMed

    Ugwonali, Obinwanne Fidelis C; Jupiter, Jesse B

    2006-09-01

    External fixation is an effective means of addressing several pathologies of the hand. The advantages of its use include the ability to achieve stable fixation, minimize soft tissue trauma at the site of injury, and allow wound care and mobilization of adjacent joints. External fixators can be constructed from material readily available in the operating room or obtained from a commercial source. Sufficient rigidity can be achieved by any of these means. Improper placement, although achieving rigid fixation, may compromise motion and overall function if basic principles of external fixation are not followed or if the anatomy of the hand is not taken into consideration. The objective of this article is to describe the technique of application of mini external fixation, emphasizing the basic principles of external fixation as they relate to the specific anatomy of the hand. In addition to fracture fixation, various other uses are described including distraction lengthening, arthrodesis, treatment of nonunion, and infection.

  14. Missing nitrogen fixation in the Benguela region

    NASA Astrophysics Data System (ADS)

    Wasmund, Norbert; Struck, Ulrich; Hansen, Anja; Flohr, Anita; Nausch, Günther; Grüttmüller, Annett; Voss, Maren

    2015-12-01

    Opposing opinions on the importance of nitrogen fixation in the northern Benguela upwelling region provoked us to investigate the magnitude of nitrogen fixation in front of northern Namibia and southern Angola. Measurements of nitrogen fixation rates using the 15N method at 66 stations during seven cruises from 2008 to 2014 showed that, in general, the 15N content in the biomass did not increase after tracer incubation with 15N2, indicating that no nitrogen fixation occurred. Correspondingly, the filamentous nitrogen-fixing cyanobacterium Trichodesmium was almost not present. The abundant picocyanobacteria did obviously not perform nitrogen fixation to a significant degree. The artificial improvement of conditions for nitrogen fixation in mesocosm experiments, including phosphate and iron additions and a warmer temperature, failed to induce nitrogen fixation. A plausible explanation of these findings is a lack of conditioned cells for nitrogen fixation in the Benguela region.

  15. Complement fixation test to C. burnetii

    MedlinePlus

    ... ency/article/003520.htm Complement fixation test to C burnetii To use the sharing features on this ... JavaScript. The complement fixation test to Coxiella burnetii ( C burnetti ) is a blood test that checks for ...

  16. WRIST ARTHRODESIS WITH MINIMAL FIXATION PRESERVING THE CARPOMETACARPAL JOINTS

    PubMed Central

    Pardini, Arlindo Gomes; Pádua Gonçalves, Rodolfo Fonseca; Freitas, Afrânio Donato; Chaves, Antonio Barbosa

    2015-01-01

    Objective: Wrist arthrodesis is a surgical procedure that should always be considered in cases of pathological conditions in which anatomical and functional structures are altered. In general, the results are very satisfactory, particularly for pain relief, and in the majority of cases, there is considerable functional improvement. Various techniques have been described, with different methods of internal fixation, most of which include the carpometacarpal joints in the fusion. The objective of this study was to evaluate the results from wrist arthrodesis using a technique that is simpler, more biological, less expensive, and does not involve the carpometacarpal joints. Methods: Fifteen patients with wrist arthrodesis were evaluated (six with sequelae from trauma, four with rheumatoid arthritis, three with Kienbock grade IV, one with Preiser and one with panarthrosis). The technique consisted of using an iliac bone plate and internal fixation with Kirschner wires, avoiding the carpometacarpal joints. Results: The evaluation was based on consolidation time (93% in seven weeks); movements of the fingers and pronosupination; pinch and grasp strength; functional evaluation through the DASH, pain and patient satisfaction questionnaires. In general, the results were similar to those of other, more aggressive techniques, and the non-inclusion of the carpometacarpal joints did not affect the final result. Conclusion: Wrist arthrodesis with fixation using Kirschner wires and an iliac bone plate, preserving the carpometacarpal joints, gives good or excellent results that are not inferior to those of other techniques that have been described. However, it presents major advantages over other methods: it is less aggressive and cheaper, and does not have the inconvenience and complications associated with the use of plates and screws. PMID:27022522

  17. Stabilization of Mobile Mandibular Segments in Mandibular Reconstruction: Use of Spanning Reconstruction Plate

    PubMed Central

    Yap, Yan Lin; Lim, Jane; Ong, Wei Chen; Yeo, Matthew; Lee, Hanjing; Lim, Thiam Chye

    2012-01-01

    The fibular free flap is the gold standard for mandibular reconstruction. Accurate 3-dimensional contouring and precise alignment of the fibula is critical for reestablishing native occlusion and facial symmetry. Following segmental mandibulectomy, the remaining mandibular fragments become freely mobile. Various stabilization methods including external fixation, intermaxillary fixation, and preplating with reconstruction plate have been used. We describe a modification to the preplating technique. After wide resection of buccal squamous cell carcinoma, our patient had an 11-cm mandibular defect from the angle of the left mandible to the right midparasymphyseal region. A single 2.0-mm Unilock® (Synthes, Singapore) plate was used to span the defect. This was placed on the vestibular aspect of the superior border of the mandibular remnants before resection. Segmental mandibulectomy was then performed with the plate removed. The spanning plate was then reattached to provide rigid fixation. The fibular bone was contoured with a single osteotomy and reattached. The conventional technique involves molding of the plate at the inferior border of the mandible. This is time-consuming and not possible in patients with distorted mandibular contour. It is also difficult to fit the osteotomized fibula to the contoured plate. In comparison, the superiorly positioned spanning plate achieve rigid fixation of the mandible while leaving the defect completely free and unhampered by hardware, allowing space for planning osteotomies and easier fixation of the neomandible. Using this modified technique, we are able to recreate the original mandibular profile with ease. PMID:23997856

  18. Stabilization of mobile mandibular segments in mandibular reconstruction: use of spanning reconstruction plate.

    PubMed

    Yap, Yan Lin; Lim, Jane; Ong, Wei Chen; Yeo, Matthew; Lee, Hanjing; Lim, Thiam Chye

    2012-09-01

    The fibular free flap is the gold standard for mandibular reconstruction. Accurate 3-dimensional contouring and precise alignment of the fibula is critical for reestablishing native occlusion and facial symmetry. Following segmental mandibulectomy, the remaining mandibular fragments become freely mobile. Various stabilization methods including external fixation, intermaxillary fixation, and preplating with reconstruction plate have been used. We describe a modification to the preplating technique. After wide resection of buccal squamous cell carcinoma, our patient had an 11-cm mandibular defect from the angle of the left mandible to the right midparasymphyseal region. A single 2.0-mm Unilock® (Synthes, Singapore) plate was used to span the defect. This was placed on the vestibular aspect of the superior border of the mandibular remnants before resection. Segmental mandibulectomy was then performed with the plate removed. The spanning plate was then reattached to provide rigid fixation. The fibular bone was contoured with a single osteotomy and reattached. The conventional technique involves molding of the plate at the inferior border of the mandible. This is time-consuming and not possible in patients with distorted mandibular contour. It is also difficult to fit the osteotomized fibula to the contoured plate. In comparison, the superiorly positioned spanning plate achieve rigid fixation of the mandible while leaving the defect completely free and unhampered by hardware, allowing space for planning osteotomies and easier fixation of the neomandible. Using this modified technique, we are able to recreate the original mandibular profile with ease.

  19. Refracture rate after plate removal from the radial metaphysis

    PubMed Central

    Houle, Jean B.; Tabrizi, Payam; Giachino, A. Alan; Benoit, Michel Y.; Richards, Robert S.; Pham, Ba; Grabowski, Jenny

    2002-01-01

    Objectives To document the refracture rate after removal of internal fixation at the metaphyseal region of the distal radius and to compare this rate to that associated with diaphyseal plate removal reported in the literature. Design A chart review with telephone follow-up. Setting Three tertiary care hospitals (in Ottawa, Burlington, Vt., and London, Ont.). Patients Fifty-three patients (54 radii) underwent elective removal of internal fixation of the distal radius after distal metaphyseal procedures. The mean follow-up was 46.8 months. Main outcome measure The refracture rate. Results No refractures were reported after plate removal, and the overall complication rate was minimal. Conclusions The refracture rate at the metaphysis of the radius after plate removal is lower than the rate after diaphyseal plate removal reported in the literature. PMID:11837922

  20. Biomechanical and biological aspects of defect treatment in fractures using helical plates.

    PubMed

    Perren, S M; Regazzoni, P; Fernandez, A A D

    2014-01-01

    The clinical case of figure 1 through figure 11 shows a series of impressive failures of plate fixation. The plates were repeatedly applied bridging a comminuted bone segment in a heavy patient. The biomechanical analysis elaborates why this happened and proposes an unconventional procedure to prevent this failure with a minimally invasive procedure. A plate bridging an open gap or a defect in a long bone diaphysis is exposed to full functional load. According to clinical observations such plate application often fails even without external load such as weight bearing. The plate risks to break through fatigue when exposed during a long time to cyclic loading. This type of failure has been observed even with broad plates as well in femoral as in tibiae. The first option to avoid such failure consists in protecting the plate by installing load sharing between plate and either bone or an additional implant. This reduces the load carried by the plate to a safe level. Load sharing with bone may be installed at surgery by establishing solid mechanical bridge between the two main fragments of the fractured bone. The optimal load sharing relies on a solid compressed contact between the main fragments. It can be established because the bone is able to take a large load which results in optimal protection of the plate. In the case of an extended comminuted bone segment it may be very difficult, traumatizing and inefficient to reconstruct the bone. In the present case it was impossible to establish load sharing through the bone. The second option protecting the plate is provided by callus bridging of the gap or defect. The formation of a solid callus bridge takes time but the fatigue failure of the plate also takes time. Therefore, the callus bridge may prevent a late fatigue failure. The surgeon may select one of several options: - Replacing the lack of bone support using a second plate which immediately alleviates plate loading. The drawback of application of a second

  1. Transit Fixatives: An Innovative Study

    PubMed Central

    A, Ravi Prakash; G, Sreenath; JK, Sonia Bai; NDVN, Shyam

    2015-01-01

    Background: Universally accepted fixative is 10% formalin which has been used for preserving the tissues and their architecture. In certain conditions, formalin might not be readily available for immediate fixation. We here by explore more economical, eco-friendly and easily available solutions that can be used as transit media/ transporting media for tissue specimens. Materials and Methods: The study included commonly available solutions like Spirit, Saline, Betadine solution, Hydrogen peroxide (H2O2), Local anesthesia (L.A), Rose water, Coconut oil, Coconut water, Ice cold water, Honey and Milk while keeping formalin as control. The fresh tissue sample was cut into multiple bits and placed in different containers for a period of 8 hours before transferring to formalin solution. Conclusion: Transit fixatives are very important in certain situations where formalin is not readily available. These fixatives can be used to fix the tissues for a period of at least 8 hours without causing any damage or distortion before they are fixed in formalin solution. PMID:25954725

  2. Plate electronics

    NASA Astrophysics Data System (ADS)

    Carlowicz, Michael

    Using a Cray T3D supercomputer and a simple assumption about the physical character of Earth's mantle, a pair of researchers from the University of California at Berkeley have built a computer model that may help explain why the planet's tectonic plates look the way they do.In creating a three-dimensional numerical simulation of convection in the Earth's interior, UC researchers Hans-Peter Bunge and Mark Richards simplified their model to account for just one major physical effect: that the viscosity of the mantle increases with depth. Reviewing some recent—but not yet widely accepted—seismic data, Bunge and Richards assumed for the sake of the model that the viscosity of the mantle increases by a factor of 30 from the lithosphere to the core-mantle boundary. Relying on that assumption, the pair ran the model for nearly three weeks on a supercomputer at Los Alamos National Laboratory and found that the simulation produced an effect similar to what we see on the surface of Earth. The model produced a surface paralleling the actual width of plates and the geometry of the plate boundaries.

  3. Understanding Nitrogen Fixation

    SciTech Connect

    Paul J. Chirik

    2012-05-25

    synthesis of ammonia, NH{sub 3}, from its elements, H{sub 2} and N{sub 2}, via the venerable Haber-Bosch process is one of the most significant technological achievements of the past century. Our research program seeks to discover new transition metal reagents and catalysts to disrupt the strong N {triple_bond} N bond in N{sub 2} and create new, fundamental chemical linkages for the construction of molecules with application as fuels, fertilizers and fine chemicals. With DOE support, our group has discovered a mild method for ammonia synthesis in solution as well as new methods for the construction of nitrogen-carbon bonds directly from N{sub 2}. Ideally these achievements will evolve into more efficient nitrogen fixation schemes that circumvent the high energy demands of industrial ammonia synthesis. Industrially, atmospheric nitrogen enters the synthetic cycle by the well-established Haber-Bosch process whereby N{sub 2} is hydrogenated to ammonia at high temperature and pressure. The commercialization of this reaction represents one of the greatest technological achievements of the 20th century as Haber-Bosch ammonia is responsible for supporting approximately 50% of the world's population and serves as the source of half of the nitrogen in the human body. The extreme reaction conditions required for an economical process have significant energy consequences, consuming 1% of the world's energy supply mostly in the form of pollution-intensive coal. Moreover, industrial H{sub 2} synthesis via the water gas shift reaction and the steam reforming of methane is fossil fuel intensive and produces CO{sub 2} as a byproduct. New synthetic methods that promote this thermodynamically favored transformation ({Delta}G{sup o} = -4.1 kcal/mol) under milder conditions or completely obviate it are therefore desirable. Most nitrogen-containing organic molecules are derived from ammonia (and hence rely on the Haber-Bosch and H{sub 2} synthesis processes) and direct synthesis from

  4. 21 CFR 886.1290 - Fixation device.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1290 Fixation device. (a) Identification. A fixation device is an AC-powered device intended for use as a fixation target for the patient during ophthalmological examination. The patient directs his or her gaze so that the visual image of the object falls...

  5. 21 CFR 886.1290 - Fixation device.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1290 Fixation device. (a) Identification. A fixation device is an AC-powered device intended for use as a fixation target for the patient during ophthalmological examination. The patient directs his or her gaze so that the visual image of the object falls...

  6. 21 CFR 886.1290 - Fixation device.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1290 Fixation device. (a) Identification. A fixation device is an AC-powered device intended for use as a fixation target for the patient during ophthalmological examination. The patient directs his or her gaze so that the visual image of the object falls...

  7. 21 CFR 886.1290 - Fixation device.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1290 Fixation device. (a) Identification. A fixation device is an AC-powered device intended for use as a fixation target for the patient during ophthalmological examination. The patient directs his or her gaze so that the visual image of the object falls...

  8. 21 CFR 886.1290 - Fixation device.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1290 Fixation device. (a) Identification. A fixation device is an AC-powered device intended for use as a fixation target for the patient during ophthalmological examination. The patient directs his or her gaze so that the visual image of the object falls...

  9. Binocular Fixation Disparity in Single Word Displays

    ERIC Educational Resources Information Center

    Paterson, Kevin B.; Jordan, Timothy R.; Kurtev, Stoyan

    2009-01-01

    It has been claimed that the recognition of words displayed in isolation is affected by the precise location at which they are fixated. However, this putative role for fixation location has yet to be reconciled with the finding from reading research that binocular fixations are often misaligned and, therefore, more than 1 location in a word is…

  10. Tissue fixation and the effect of molecular fixatives on downstream staining procedures.

    PubMed

    Howat, William J; Wilson, Beverley A

    2014-11-01

    It is impossible to underplay the importance of fixation in histopathology. Whether the scientist is interested in the extraction of information on lipids, proteins, RNA or DNA, fixation is critical to this extraction. This review aims to give a brief overview of the current "state of play" in fixation and focus on the effect fixation, and particularly the effect of the newer brand of "molecular fixatives" have on morphology, histochemistry, immunohistochemistry and RNA/DNA analysis. A methodology incorporating the creation of a fixation tissue microarray for the study of the effect of fixation on histochemistry is detailed.

  11. Volar Locking Plate Breakage after Nonunion of a Distal Radius Osteotomy

    PubMed Central

    Rodríguez-Alabau, Sergi; Soldado, Francisco; Mir, Xavier

    2016-01-01

    We report a 38-year-old male with a nonunion followed by plate breakage after volar plating of a distal radius osteotomy. Volar locking plates have added a new approach to the treatment of distal radius malunions, due to a lower morbidity of the surgical approach and the strength of the final construction, allowing early mobilization and return to function. Conclusion. Plate breakage is an uncommon complication of volar locking plate fixation. To our knowledge, few cases have been described after a distal radius fracture and no case has been described after a distal radius corrective osteotomy. In the present case, plate breakage appears to have occurred as a result of a combination of multiple factors as the large corrective lengthening osteotomy, the use of demineralized bone matrix instead of bone graft, and the inappropriate fixation technique as an unfilled screw on the osteotomy site, rather than the choice of plate. PMID:28003828

  12. Pitfalls in the application of distal femur plates for fractures.

    PubMed

    Collinge, Cory A; Gardner, Michael J; Crist, Brett D

    2011-11-01

    Despite design features intended to aid the surgeon in restoring proper alignment, malunion and implant-related problems are relatively common after a distal femur fracture treated with plate fixation. This article presents case examples of these problems followed by a discussion of the relevant distal femoral anatomy, design features of modern locked distal femur plating systems, and technical points necessary to avoid malunion and implant-related problems when using these devices.

  13. Detail of interior of compressed air chamber showing top of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail of interior of compressed air chamber showing top of working chamber and tie rods that strengthen the outer shell plates of the compression chamber. - Sub Marine Explorer, Located along the beach of Isla San Telmo, Pearl Islands, Isla San Telmo, Former Panama Canal Zone, CZ

  14. External fixation is more suitable for intra-articular fractures of the distal radius in elderly patients

    PubMed Central

    Ma, Chuang; Deng, Qiang; Pu, Hongwei; Cheng, Xinchun; Kan, Yuhua; Yang, Jing; Yusufu, Aihemaitijiang; Cao, Li

    2016-01-01

    The purpose of this study was to compare the functional outcomes, psychological impact, and complication rates associated with external fixation and volar or dorsal plating in relation to the functional parameters following treatment of intra-articular fractures of the distal radius (IFDR) in patients older than 65 years. We hypothesized that using volar or dorsal plating would improve functional outcomes, but that it would be associated with more complications and equivalent functional outcomes when compared with the external fixation group. A total of 123 consecutive patients suffering from IFDR were recruited into the study. The patients were measured for clinical, radiological, and psychosocial functioning outcomes and were followed up after 1 week and 3, 6 and 12 months. After 3 months, the plating group had better pronation (P=0.001), supination, (P=0.047) and extension (P=0.043) scores. These differences were somewhat attenuated by 6 months and disappeared at 1 year. The plating group had a greater occurrence of wound infection (P=0.043), tendonitis, (P=0.024) and additional surgery compared with the external fixation group. The only TNO-AZL Adult Quality of Life scores in the plating group that were lower than those in the external fixation group were in the “gross motor” category (walking upstairs, bending over, walking 500 yards; P=0.023). Internal fixation was more advantageous than external fixation in the early rehabilitation period; after 1 year the outcomes were similar. The plating group showed significantly higher levels of wound infection and tendonitis and had a greater need for additional surgeries. PMID:27408765

  15. Bendability of aluminiumand steel-clad chromium plates

    NASA Astrophysics Data System (ADS)

    Yoshida, Fusahito; Okada, Tatsuo; Itoh, Misao; Harada, Yasunori; Ohmori, Masanobu

    1998-05-01

    The present paper describes how the cladding of chromium plate with dissimilar metals improves the plastic bendability of the chromium. Three-point bending tests at various temperatures were performed for three types of chromium specimens: a monolithic chromium plate, aluminium- and steel-clad chromium plate. The aluminium-clad chromium plate was bent at 343 K up to a bent angle of 90 degrees without failure, even when the chromium layer was located outside of the plate (tension side), while the monolithic chromium plate could be bent exclusively at temperatures above 403 K. When the chromium layer was located inside of the steel-clad chromium plate (compression side), the plate was successfully bent at 307 K. The FE stress analysis of bending proved that the cladding of chromium plates with proper metals of different kinds is effective to reduce the tensile stress in chromium induced during bending and also the residual stress existing after bending operation.

  16. Stabilization of a short juxta-articular bone segment with a circular external fixator.

    PubMed

    Bronson, Dwight G; Samchukov, Mikhail L; Birch, John G

    2002-04-01

    The objective of the current study was to evaluate the stabilization of a simulated juxta-articular bone segment with a circular external fixator, and to determine which method of fixation improved bending stabilization while preserving the axial dynamization of a three-wire configuration. Frames were divided into three groups: wire, half-pin and hybrid and tested in axial compression, torsion, anteroposterior bending and mediolateral bending. Hybrid frames using 4 mm half-pins improved the anteroposterior stabilization of the short bone segment while maintaining axial characteristics similar to a three-wire frame. Increasing the bending stabilization will improve bone segment alignment while permitting axial micromotion beneficial to bone healing.

  17. Effect of induced aniseikonia on fixation performance.

    PubMed

    Remole, A

    1988-01-01

    The purpose of the study was to determine to what extent induced aniseikonia affects fixation performance. Aniseikonia was induced in the vertical meridian only, whereas fixation alignment was monitored in the horizontal meridian. A previously developed technique based on the dependency of border enhancement bandwidth on fixation eccentricity was used to monitor deviations from central fixation during fusion. Stress on the fusion mechanism was supplied by controlled increments of forced horizontal vergence. It was found that deviation from central fixation in the horizontal meridian generally increases with increasing amounts of vertical aniseikonia. The effect is particularly pronounced for small amounts of aniseikonia.

  18. Percutaneous screw fixation of fractures of the iliac wing and fracture-dislocations of the sacro-iliac joint (OTA Types 61-B2.2 and 61-B2.3, or Young-Burgess "lateral compression type II" pelvic fractures).

    PubMed

    Starr, Adam J; Walter, James C; Harris, Robert W; Reinert, Charles M; Jones, Alan L

    2002-02-01

    A technique for closed reduction and percutaneous screw fixation of fractures of the iliac wing and fracture-dislocations of the sacro-iliac joint is presented. Twenty-seven pelvic fractures were treated with attempted closed reduction followed by percutaneous screw fixation. Closed reduction failed in two patients. In the other twenty-five, closed reduction to within one centimeter of residual displacement was obtained, and was followed by stabilization with percutaneously placed cannulated screws. Complications included dislodgment of a screw from the superior pubic ramus in one patient, and partial cut-out of a screw along the inner cortex of the iliac wing in another. Two patients were lost to follow-up before fracture union occurred. The remaining twenty-three patients were followed-up for an average of twenty-seven months (range, 18-48 months). All of the fractures healed in the twenty-three patients who were not lost to follow-up. All but two of the patients who were working before injury returned to work. All but one of the patients was satisfied with the outcome of their pelvic fracture treatment. Closed reduction and percutaneous screw fixation of fractures of the posterior portion of the iliac wing yields acceptable reductions, with minimal blood loss and limited damage to the surrounding soft tissues.

  19. Transpiration effects in perforated plate aerodynamics

    NASA Astrophysics Data System (ADS)

    Szwaba, R.; Ochrymiuk, T.

    2016-10-01

    Perforated walls find a wide use as a method of flow control and effusive cooling. Experimental investigations of the gas flow past perforated plate with microholes (110μm) were carried out. The wide range of pressure at the inlet were investigated. Two distinguishable flow regimes were obtained: laminar and turbulent regime.The results are in good agreement with theory, simulations and experiments on large scale perforated plates and compressible flows in microtubules. Formulation of the transpiration law was associated with the porous plate aerodynamics properties. Using a model of transpiration flow the “aerodynamic porosity” could be determined for microholes.

  20. Femoral neck fracture fixation: rigidity of five techniques compared.

    PubMed Central

    Mackechnie-Jarvis, A C

    1983-01-01

    Artificial cadaveric femoral neck fractures were internally fixed with five different devices and subjected to cyclical loading of 0-1.0 kilonewtons (approximately one body weight) whilst in an anatomical position. Displacement of the proximal fragment was detected by a transducer and charted. Bone strength was assessed by a preliminary control loading phase on the intact bone. Efficiency of each fracture fixator could then be directly compared by the relative movement in each case. Five specimens each were tested with Moore's Pins, Trifin Nail, Garden Screws and a sliding screw-plate (OEC Ltd). By the criteria of the experiment, which put a severe shearing load on the implant, none of these devices reliably bore the representative body weight. An extended barrel-plate, which supported the sliding screw almost up to the fracture line, was then made. This device, employing some of Charnley's concepts, tolerated body weight in four cases out of five. PMID:6887186

  1. An introduction to the 'Mennen plate' and its use in treatment of fractures of the edentulous mandible.

    PubMed

    Maung Aung, T; Brook, I M; Crofts, C E; Trowbridge, E A

    1990-08-01

    A paraskeletal clamp plate (Mennen) offers a novel method of fixation for mandibular fractures. Its application is relatively atraumatic and this together with the minimal disruption to the local blood supply may make this clamp particularly suited to fixation of fractures of the atrophic edentulous jaw. Its use in six such cases is reported.

  2. Tailor's bunion. Is fixation necessary?

    PubMed

    Pontious, J; Brook, J W; Hillstrom, H J

    1996-02-01

    Tailor's bunion or bunionette are terms that describe a pathologic enlargement occurring laterally on the fifth metatarsophalangeal joint. Regardless of the etiology that precipitates the deformity, the resulting abnormal protrusion of soft tissue or bone can result in pain for the patient. Symptoms can range from mild discomfort to severe, debilitating pain. The patient may present with pain dorsolaterally, laterally, or plantarly. The symptoms are mechanically induced, and are often associated with hyperkeratotic lesions and adventitious bursae. Patients complain most often that they cannot find comfortable shoes. The authors compare the effectiveness of fixated versus nonfixated distal osteotomies of the fifth metatarsal for the correction of tailor's bunion. This study shows that fixation can help control postoperative dorsal displacement of the fifth metatarsal capital fragment (p < 0.0001) and produce less shortening of the metatarsal resulting in fewer complications.

  3. Nitrogen fixation by marine cyanobacteria.

    PubMed

    Zehr, Jonathan P

    2011-04-01

    Discrepancies between estimates of oceanic N(2) fixation and nitrogen (N) losses through denitrification have focused research on identifying N(2)-fixing cyanobacteria and quantifying cyanobacterial N(2) fixation. Previously unrecognized cultivated and uncultivated unicellular cyanobacteria have been discovered that are widely distributed, and some have very unusual properties. Uncultivated unicellular N(2)-fixing cyanobacteria (UCYN-A) lack major metabolic pathways including the tricarboxylic acid cycle and oxygen-evolving photosystem II. Genomes of the oceanic N(2)-fixing cyanobacteria are highly conserved at the DNA level, and genetic diversity is maintained by genome rearrangements. The major cyanobacterial groups have different physiological and ecological constraints that result in highly variable geographic distributions, with implications for the marine N-cycle budget.

  4. [Efficacy of halo-vest fixation in the assessment and prediction of the effectiveness of permanent fixation in a patient with basilar invagination with ambiguous vertebral instability].

    PubMed

    Osawa, Shin-ichiro; Suzuki, Shinsuke; Sasaki, Toru; Kanamori, Masayuki; Uenohara, Hiroshi

    2014-10-01

    Basilar invagination is a developmental anomaly of the craniovertebral junction in which the odontoid abnormally prolapses into the foramen magnum. It is also associated with Chiari malformation, syringomyelia, and hydrocephalus. Patients require surgical treatment to prevent progression of neurological symptoms, but assessment of anterior or posterior decompression can be difficult owing to bone instability and ambiguous compression of neural structures. Here, we describe a case of basilar invagination in a young adult. He presented with neurological symptoms, including syringomyelia, 3 months after a traffic trauma that might have led to instability of the bony structures. Since it was unclear whether the instability of the bony structures contributed to the clinical deterioration, the patient was first treated using halo-vest fixation. Significant improvements were observed in both neurological symptoms and magnetic resonance images. These results justified the invasive fixation and the patient was treated further with an occipito-cervical fusion ; good results were achieved in this case. Owing to the invasiveness of the procedure, occipito-cervical fixation should only be adopted following strict indication criteria. Halo-vest fixation was effective in treating the instability of the bony structures and as a trial treatment for permanent fixation.

  5. Shock wave absorber having apertured plate

    DOEpatents

    Shin, Y.W.; Wiedermann, A.H.; Ockert, C.E.

    1983-08-26

    The shock or energy absorber disclosed herein utilizes an apertured plate maintained under the normal level of liquid flowing in a piping system and disposed between the normal liquid flow path and a cavity pressurized with a compressible gas. The degree of openness (or porosity) of the plate is between 0.01 and 0.60. The energy level of a shock wave travelling down the piping system thus is dissipated by some of the liquid being jetted through the apertured plate toward the cavity. The cavity is large compared to the quantity of liquid jetted through the apertured plate, so there is little change in its volume. The porosity of the apertured plate influences the percentage of energy absorbed.

  6. Shock wave absorber having apertured plate

    DOEpatents

    Shin, Yong W.; Wiedermann, Arne H.; Ockert, Carl E.

    1985-01-01

    The shock or energy absorber disclosed herein utilizes an apertured plate maintained under the normal level of liquid flowing in a piping system and disposed between the normal liquid flow path and a cavity pressurized with a compressible gas. The degree of openness (or porosity) of the plate is between 0.01 and 0.60. The energy level of a shock wave travelling down the piping system thus is dissipated by some of the liquid being jetted through the apertured plate toward the cavity. The cavity is large compared to the quantity of liquid jetted through the apertured plate, so there is little change in its volume. The porosity of the apertured plate influences the percentage of energy absorbed.

  7. Hinged external fixation for complex fracture-dislocation of the elbow in elderly people.

    PubMed

    Maniscalco, P; Pizzoli, A L; Renzi Brivio, L; Caforio, M

    2014-12-01

    The authors report their experience of treating complex elbow fracture-dislocations in elderly people, using a minimally-invasive approach with a new articulated external fixator that is associated with minimal internal fixation. The clinical results for 19 patients are presented according to outcome factors, such as range of motion, pain and function, rate and type of complications, and reoperation rate. The results indicate that this treatment strategy should be considered as a good alternative to other treatment options reported in the literature, including conservative treatment, ORIF with angular stable plates and total elbow arthroplasty.

  8. Smaller Fixation Target Size Is Associated with More Stable Fixation and Less Variance in Threshold Sensitivity

    PubMed Central

    Okano, Kana; Koshiji, Risako; Funaki, Wakana; Shoji, Nobuyuki

    2016-01-01

    The aims of this randomized observational case control study were to quantify fixation behavior during standard automated perimetry (SAP) with different fixation targets and to evaluate the relationship between fixation behavior and threshold variability at each test point in healthy young participants experienced with perimetry. SAP was performed on the right eyes of 29 participants using the Octopus 900 perimeter, program 32, dynamic strategy. The fixation targets of Point, Cross, and Ring were used for SAP. Fixation behavior was recorded using a wearable eye-tracking glass. All participants underwent SAP twice with each fixation target in a random fashion. Fixation behavior was quantified by calculating the bivariate contour ellipse area (BCEA) and the frequency of deviation from the fixation target. The BCEAs (deg2) of Point, Cross, and Ring targets were 1.11, 1.46, and 2.02, respectively. In all cases, BCEA increased significantly with increasing fixation target size (p < 0.05). The logarithmic value of BCEA demonstrated the same tendency (p < 0.05). A positive correlation was identified between fixation behavior and threshold variability for the Point and Cross targets (ρ = 0.413–0.534, p < 0.05). Fixation behavior increased with increasing fixation target size. Moreover, a larger fixation behavior tended to be associated with a higher threshold variability. A small fixation target is recommended during the visual field test. PMID:27829030

  9. Evaluation of functional outcome and complications of locking calcaneum plate for fracture calcaneum

    PubMed Central

    Kumar, Surender; Krishna, Loveneesh G.; Singh, Davinder; Kumar, Pawan; Arora, Sumit; Dhaka, Sunil

    2015-01-01

    Background Open reduction and internal fixation (ORIF) is the treatment of choice for displaced intra-articular calcaneal fracture at many orthopaedic trauma centres. In this prospective study, we evaluated the functional outcome and complications of locking compressive calcaneum plate for displaced intra-articular fracture calcaneum. Methods Between October 2011 and March 2012, 30 patients with displaced intra-articular fracture calcaneum attending the outdoor and emergency of our institute were included in the study. All the included patients were operated using standard lateral approach and followed up to 1 year. Results Of 30 patients, 14 (48%) patients were Sander's type II, 10 (33%) were type III, and 6 (20%) were type IV. All the patients were evaluated post-operatively. Articular surface of posterior facet of calcaneum and crucial angle of Gissane was maintained in all patients. Four patients had post-operative Boehler's angle <20° and 26 patients had between 21° and 40°. All the patients having post-operative Boehler's angle <20° were type IV as compared to types II and III (statistically significant). Ninety-six percentage of patients having post-operative Boehler's angle 21–40° were more satisfied at 1 year as compared to 25% of patients having post-operative Boehler's angle <20° (statistically significant). Complications were present in 6 (20%) patients. Conclusion ORIF with locking compressive plate in displaced intra-articular fracture calcaneum gives good outcome. Results are more favourable in less comminuted as compared to more comminuted. Maintenance of Boehler's angle is also necessary for satisfactory results along with maintenance of articular congruence of posterior facet of calcaneum and crucial angle of Gissane. PMID:26155049

  10. [Formation of compressive bandage after sclerotherapy for lower limb varices].

    PubMed

    Zatonskikh, B Ia; Banas, N B

    2003-01-01

    Invention concerns compressive sclerotherapy as a treatment modality for lower limb varices. Technical result of investigation is the development of compressive bandage that creates and maintains adequate level of limb compression both in supine position (during bed rest) and standing or walking. Technical result is achieved by formation of two compressive layers of elastic bandage. Highly expansible elastic bandage is used for the first layer aimed for fixation and compression of latex or foam pads at injection sites to create local compression of variceal nodes. Open toe elastic stocking (I compression class) is placed over the bandage to maintain adequate compression during bed rest. The second external layer consists of elastic bandage with moderate expansion (II compression class). It is placed over the first one from toes to thigh upper third and creates optimal compression in patient's vertical position. The patient is permitted to take it off or loose exclusively in supine position, to wash or refresh foot with wet towel, to change it with a new one.

  11. Fixation strategies for retinal immunohistochemistry.

    PubMed

    Stradleigh, Tyler W; Ishida, Andrew T

    2015-09-01

    Immunohistochemical and ex vivo anatomical studies have provided many glimpses of the variety, distribution, and signaling components of vertebrate retinal neurons. The beauty of numerous images published to date, and the qualitative and quantitative information they provide, indicate that these approaches are fundamentally useful. However, obtaining these images entailed tissue handling and exposure to chemical solutions that differ from normal extracellular fluid in composition, temperature, and osmolarity. Because the differences are large enough to alter intercellular and intracellular signaling in neurons, and because retinae are susceptible to crush, shear, and fray, it is natural to wonder if immunohistochemical and anatomical methods disturb or damage the cells they are designed to examine. Tissue fixation is typically incorporated to guard against this damage and is therefore critically important to the quality and significance of the harvested data. Here, we describe mechanisms of fixation; advantages and disadvantages of using formaldehyde and glutaraldehyde as fixatives during immunohistochemistry; and modifications of widely used protocols that have recently been found to improve cell shape preservation and immunostaining patterns, especially in proximal retinal neurons.

  12. Fixation Strategies For Retinal Immunohistochemistry

    PubMed Central

    Stradleigh, Tyler W.; Ishida, Andrew T.

    2015-01-01

    Immunohistochemical and ex vivo anatomical studies have provided many glimpses of the variety, distribution, and signaling components of vertebrate retinal neurons. The beauty of numerous images published to date, and the qualitative and quantitative information they provide, indicate that these approaches are fundamentally useful. However, obtaining these images entailed tissue handling and exposure to chemical solutions that differ from normal extracellular fluid in composition, temperature, and osmolarity. Because the differences are large enough to alter intercellular and intracellular signaling in neurons, and because retinae are susceptible to crush, shear, and fray, it is natural to wonder if immunohistochemical and anatomical methods disturb or damage the cells they are designed to examine. Tissue fixation is typically incorporated to guard against this damage and is therefore critically important to the quality and significance of the harvested data. Here, we describe mechanisms of fixation; advantages and disadvantages of using formaldehyde and glutaraldehyde as fixatives during immunohistochemistry; and modifications of widely used protocols that have recently been found to improve cell shape preservation and immunostaining patterns, especially in proximal retinal neurons. PMID:25892361

  13. Treatment of distal intraarticular tibial fractures: A biomechanical evaluation of intramedullary nailing vs. angle-stable plate osteosynthesis.

    PubMed

    Kuhn, Sebastian; Greenfield, Julia; Arand, Charlotte; Jarmolaew, Andrey; Appelmann, Philipp; Mehler, Dorothea; Rommens, Pol M

    2015-10-01

    In factures of the distal tibia with simple articular extension, the optimal surgical treatment remains debatable. In clinical practice, minimally invasive plate osteosynthesis and intramedullary nailing are both routinely performed. Comparative biomechanical studies of different types of osteosynthesis of intraarticular distal tibial fractures are missing due to the lack of an established model. The goal of this study was first to establish a biomechanical model and second to investigate, which are the biomechanical advantages of angle-stable plate osteosynthesis and intramedullary nailing of distal intraarticular tibial fractures. Seven 4(th) generation biomechanical composite tibiae featuring an AO 43-C2 type fracture were implanted with either osteosynthesis technique. After primary lag screw fixation, 4-hole Medial Distal Tibial Plate (MDTP) with triple proximal and quadruple distal screws or intramedullary nailing with double proximal and triple 4.0mm distal interlocking were implanted. The stiffness of the implant-bone constructs and interfragmentary movement were measured under non-destructive axial compression (350 and 600 N) and torsion (1.5 and 3Nm). Destructive axial compression testing was conducted with a maximal load of up to 1,200 N. No overall superior biomechanical results can be proclaimed for either implant type. Intramedullary nailing displays statistically superior results for axial loading in comparison to the MDTP. Torsional loading resulted in non-statistically significant differences for the two-implant types with higher stability in the MDTP group. From a biomechanical view, the load sharing intramedullary nail might be more forgiving and allow for earlier weight bearing in patients with limited compliance.

  14. In situ stabilization/fixation of chromium-contaminated soil

    SciTech Connect

    Greetis, T.A.; Werntges, W.; Hockenberry, D.

    1996-12-31

    An electroplating operation at a US Army installation was closed in accordance with Resource Conservation and Recovery Act (RCRA) regulations using in situ stabilization/fixation. Since the plating line was located inside of a building immediately adjacent to other ongoing plating lines, the selected and approved technology involved the use of an electric-powered drill rig retrofitted with a mixing blade auger system, and operated within a negative-pressure enclosure. The stabilization process included the introduction of a reagent mixture developed and defined during in situ pilot tests and stabilization studies. Upon completion of each stabilized/fixed column, representative sampling was conducted to verify the success of the process. Concentrations of chromium using the Toxicity Characteristic Leaching Procedure (TCLP) were reduced from 220 mg/L detected in soils prior to the stabilization/fixation process, to below laboratory detection limits in treated columns. Ultimately, the electroplating collection sump was closed in accordance with the approved closure plan, and the owner constructed a new concrete sump pit fitted with a welded steel sheet containment liner.

  15. Reconstruction plates for stabilization of mid-shaft clavicle fractures: differences between nonlocked and locked plates in two different positions.

    PubMed

    Robertson, Claire; Celestre, Paul; Mahar, Andrew; Schwartz, Alexandra

    2009-01-01

    Reconstruction plates permit contouring to the irregular anatomic shape of the clavicle. This study evaluated the biomechanical stability of locking and nonlocking clavicle reconstruction plates for treating midshaft, transverse fractures, comparing anterior-inferior to superior plate position. Twenty-four synthetic clavicles with mid-shaft fractures were repaired with either a locking or nonlocking clavicle reconstruction plate in either the anterior-inferior or superior plate position (n = 6/group). Repaired constructs were tested in axial compression, axial torsion, and cantilever bending failure. In compression, anterior-inferior plates were significantly stiffer than superior plates and locked plates stiffer than nonlocked. In torsion, anterior-inferior plates were stiffer, with a significant interaction term that favored anterior-inferior locked and superior nonlocked plates. In cantilever bending, superior plates had a significantly higher bending failure load and stiffness. Anterior-inferior plates failed at a significantly lower load ( approximately 40 N or approximately 4 kg), which could potentially occur in the postoperative period.

  16. The Clavicular Hook Plate: Consequences in Three Cases.

    PubMed

    Chandrasenan, Jeevan; Badhe, Sachin; Cresswell, Timothy; De Beer, Joe

    2007-10-01

    The small fragment AO clavicular hook plate is indicated for certain fractures of the lateral end of clavicle and for symptomatic acromio-clavicular joint dislocations where there is rupture of the stabilizing ligaments. The complex anatomy and biomechanics of the acromio-clavicular joint can lead to complications that result in damage to the joint itself or acromial erosion. In addition, the rotator cuff complex is at risk of injury when inserting the plate. We report three cases where patients who underwent hook plate fixation subsequently required removal of the implant due to complications previously unreported in current literature.

  17. Bicondylar tibial plateau fractures managed with the Sheffield Hybrid Fixator. Biomechanical study and operative technique.

    PubMed

    Ali, A M; Yang, L; Hashmi, M; Saleh, M

    2001-12-01

    The two main challenges in the management of bicondylar tibial plateau fractures are: Firstly, the compromised skin and soft tissue envelope which invite a high rate of complications following attempted open reduction and dual plating. Secondly, poor bone quality and comminuted fracture patterns, which create difficulty in achieving stable fixation. Although dual plating is considered to be the best mechanical method of stabilizing these complex fractures, there remains concern regarding the high rate of complications associated with extensive soft tissue dissection, required for the insertion of these plates in an already compromised knee. The Sheffield Hybrid fixator (SHF) technique offers a solution to the two main problems of these difficult fractures by minimizing soft tissue dissection, since bone fragments are reduced and fixed percutaneously, and providing superior cancellous bone purchase with beam loading stabilization for comminuted fractures. Our biomechanical testing showed the SHF with four tensioned wires to be as strong as dual plating and able to provide adequate mechanical stability in the fixation of bicondylar tibial plateau fractures. This was confirmed clinically by a prospective review of the use of the SHF at our centre, for managing complex and high-energy tibial plateau fractures with a good final outcome and no cases of deep infection or septic arthritis.

  18. Compression and contact area of anterior strut grafts in spinal instrumentation: a biomechanical study

    PubMed Central

    2013-01-01

    Background Anterior bone grafts are used as struts to reconstruct the anterior column of the spine in kyphosis or following injury. An incomplete fusion can lead to later correction losses and compromise further healing. Despite the different stabilizing techniques that have evolved, from posterior or anterior fixating implants to combined anterior/posterior instrumentation, graft pseudarthrosis rates remain an important concern. Furthermore, the need for additional anterior implant fixation is still controversial. In this bench-top study, we focused on the graft-bone interface under various conditions, using two simulated spinal injury models and common surgical fixation techniques to investigate the effect of implant-mediated compression and contact on the anterior graft. Methods Calf spines were stabilised with posterior internal fixators. The wooden blocks as substitutes for strut grafts were impacted using a “pressfit” technique and pressure-sensitive films placed at the interface between the vertebral bone and the graft to record the compression force and the contact area with various stabilization techniques. Compression was achieved either with posterior internal fixator alone or with an additional anterior implant. The importance of concomitant ligament damage was also considered using two simulated injury models: pure compression Magerl/AO fracture type A or rotation/translation fracture type C models. Results In type A injury models, 1 mm-oversized grafts for impaction grafting provided good compression and fair contact areas that were both markedly increased by the use of additional compressing anterior rods or by shortening the posterior fixator construct. Anterior instrumentation by itself had similar effects. For type C injuries, dramatic differences were observed between the techniques, as there was a net decrease in compression and an inadequate contact on the graft occurred in this model. Under these circumstances, both compression and the

  19. Pulse compression and prepulse suppression apparatus

    DOEpatents

    Dane, Clifford B.; Hackel, Lloyd A.; George, Edward V.; Miller, John L.; Krupke, William F.

    1993-01-01

    A pulse compression and prepulse suppression apparatus (10) for time compressing the output of a laser (14). A pump pulse (46) is separated from a seed pulse (48) by a first polarized beam splitter (20) according to the orientation of a half wave plate (18). The seed pulse (48) is directed into an SBS oscillator (44) by two plane mirrors (22, 26) and a corner mirror (24), the corner mirror (24) being movable to adjust timing. The pump pulse (46) is directed into an SBS amplifier 34 wherein SBS occurs. The seed pulse (48), having been propagated from the SBS oscillator (44), is then directed through the SBS amplifier (34) wherein it sweeps the energy of the pump pulse (46) out of the SBS amplifier (34) and is simultaneously compressed, and the time compressed pump pulse (46) is emitted as a pulse output (52). A second polarized beam splitter (38) directs any undepleted pump pulse 58 away from the SBS oscillator (44).

  20. Pulse compression and prepulse suppression apparatus

    DOEpatents

    Dane, C.B.; Hackel, L.A.; George, E.V.; Miller, J.L.; Krupke, W.F.

    1993-11-09

    A pulse compression and prepulse suppression apparatus (10) for time compressing the output of a laser (14). A pump pulse (46) is separated from a seed pulse (48) by a first polarized beam splitter (20) according to the orientation of a half wave plate (18). The seed pulse (48) is directed into an SBS oscillator (44) by two plane mirrors (22, 26) and a corner mirror (24), the corner mirror (24) being movable to adjust timing. The pump pulse (46) is directed into an SBS amplifier 34 wherein SBS occurs. The seed pulse (48), having been propagated from the SBS oscillator (44), is then directed through the SBS amplifier (34) wherein it sweeps the energy of the pump pulse (46) out of the SBS amplifier (34) and is simultaneously compressed, and the time compressed pump pulse (46) is emitted as a pulse output (52). A second polarized beam splitter (38) directs any undepleted pump pulse 58 away from the SBS oscillator (44).

  1. Overcoming fixation with repeated memory suppression.

    PubMed

    Angello, Genna; Storm, Benjamin C; Smith, Steven M

    2015-01-01

    Fixation (blocks to memories or ideas) can be alleviated not only by encouraging productive work towards a solution, but, as the present experiments show, by reducing counterproductive work. Two experiments examined relief from fixation in a word-fragment completion task. Blockers, orthographically similar negative primes (e.g., ANALOGY), blocked solutions to word fragments (e.g., A_L_ _GY) in both experiments. After priming, but before the fragment completion test, participants repeatedly suppressed half of the blockers using the Think/No-Think paradigm, which results in memory inhibition. Inhibiting blockers did not alleviate fixation in Experiment 1 when conscious recollection of negative primes was not encouraged on the fragment completion test. In Experiment 2, however, when participants were encouraged to remember negative primes at fragment completion, relief from fixation was observed. Repeated suppression may nullify fixation effects, and promote creative thinking, particularly when fixation is caused by conscious recollection of counterproductive information.

  2. Turbulence in Compressible Flows

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Lecture notes for the AGARD Fluid Dynamics Panel (FDP) Special Course on 'Turbulence in Compressible Flows' have been assembled in this report. The following topics were covered: Compressible Turbulent Boundary Layers, Compressible Turbulent Free Shear Layers, Turbulent Combustion, DNS/LES and RANS Simulations of Compressible Turbulent Flows, and Case Studies of Applications of Turbulence Models in Aerospace.

  3. C2–3 Fusion, C3–4 Cord Compression and C1–2 Posterior Facetal Instability: An Evaluation of Treatment Strategy Based on Four Surgically Treated Cases

    PubMed Central

    2016-01-01

    Study Design Four patients had C2–3 vertebral fusion and radiologically demonstrated cord compression at C3–4 level related to disc bulge with or without association of osteophytes and C1–2 posterior facetal dislocation. The outcome of treatment by atlantoaxial and subaxial facetal fixation is discussed. Purpose The article evaluates the significance of atlantoaxial facetal instability in cases having C2–3 vertebral fusion and cord compression at the level of C3–4 disc. Overview of Literature C2–3 vertebral fusions are frequently encountered in association with basilar invagination and chornic atlantoaxial dislocations. Even when basilar invagination and atlantoaxial dislocation are not identified by conventional parameters, atlantoaxial instability can be the nodal point of pathogenesis in cases with C2–3 vertebral fusion. Methods Between June 2013 and November 2014 four patients having C2–3 fusion presented with progressive symptoms of myelopathy that were related to cord compression at the level opposite the C3–4 disc space. Further investigations revealed C1–2 posterior facetal dislocation. Results All patients were males. Ages ranged from 18 to 50 years (average, 36 years). All patients were treated by atlantoaxial facetal plate and screw, and subaxial single or multi-segmental transarticular screw fixation. Follow-up (average, 15 months) using a recently described clinical grading system and the Japanese Orthopaedic Association scoring system confirmed marked improvement of symptoms. Conclusions Identification and treatment of atlantoaxial facetal instability may be crucial for a successful outcome in cases having C2–3 fusion and high cervical (C3–4) disc related cord compression. PMID:27340520

  4. The Combinations of Thermal and Load Stresses for the Onset of Permanent Buckling in Plates

    NASA Technical Reports Server (NTRS)

    Zender, George W; Pride, Richard A

    1957-01-01

    A simple and practical method for evaluating the onset of permanent buckling in plates in the presence of combined thermal and compressive load stresses is outlined. A particular application of the method shows reasonable agreement with tests of 17-7 PH stainless-steel square tubes. The results indicate that the compressive load stress which the plate can support at the onset of permanent buckling is substantially reduced as the temperature difference of the plate and adjoining members increases.

  5. Methanotrophy induces nitrogen fixation during peatland development.

    PubMed

    Larmola, Tuula; Leppänen, Sanna M; Tuittila, Eeva-Stiina; Aarva, Maija; Merilä, Päivi; Fritze, Hannu; Tiirola, Marja

    2014-01-14

    Nitrogen (N) accumulation rates in peatland ecosystems indicate significant biological atmospheric N2 fixation associated with Sphagnum mosses. Here, we show that the linkage between methanotrophic carbon cycling and N2 fixation may constitute an important mechanism in the rapid accumulation of N during the primary succession of peatlands. In our experimental stable isotope enrichment study, previously overlooked methane-induced N2 fixation explained more than one-third of the new N input in the younger peatland stages, where the highest N2 fixation rates and highest methane oxidation activities co-occurred in the water-submerged moss vegetation.

  6. Methanotrophy induces nitrogen fixation during peatland development

    PubMed Central

    Larmola, Tuula; Leppänen, Sanna M.; Tuittila, Eeva-Stiina; Aarva, Maija; Merilä, Päivi; Fritze, Hannu; Tiirola, Marja

    2014-01-01

    Nitrogen (N) accumulation rates in peatland ecosystems indicate significant biological atmospheric N2 fixation associated with Sphagnum mosses. Here, we show that the linkage between methanotrophic carbon cycling and N2 fixation may constitute an important mechanism in the rapid accumulation of N during the primary succession of peatlands. In our experimental stable isotope enrichment study, previously overlooked methane-induced N2 fixation explained more than one-third of the new N input in the younger peatland stages, where the highest N2 fixation rates and highest methane oxidation activities co-occurred in the water-submerged moss vegetation. PMID:24379382

  7. Nitrogen fixation method and apparatus

    DOEpatents

    Chen, Hao-Lin

    1983-01-01

    A method and apparatus for achieving nitrogen fixation includes a volumetric electric discharge chamber. The volumetric discharge chamber provides an even distribution of an electron beam, and enables the chamber to be maintained at a controlled energy to pressure (E/p) ratio. An E/p ratio of from 5 to 15 kV/atm of O.sub.2 /cm promotes the formation of vibrationally excited N.sub.2. Atomic oxygen interacts with vibrationally excited N.sub.2 at a much quicker rate than unexcited N.sub.2, greatly improving the rate at which NO is formed.

  8. Nitrogen fixation method and apparatus

    DOEpatents

    Chen, H.L.

    1983-08-16

    A method and apparatus for achieving nitrogen fixation includes a volumetric electric discharge chamber. The volumetric discharge chamber provides an even distribution of an electron beam, and enables the chamber to be maintained at a controlled energy to pressure (E/p) ratio. An E/p ratio of from 5 to 15 kV/atm of O[sub 2]/cm promotes the formation of vibrationally excited N[sub 2]. Atomic oxygen interacts with vibrationally excited N[sub 2] at a much quicker rate than unexcited N[sub 2], greatly improving the rate at which NO is formed. 1 fig.

  9. Image recorder with microwave fixation

    SciTech Connect

    Hosono, N.; Isaka, K.

    1984-11-13

    The present invention is directed to improvement in an image recorder for recording developed images or toner images by microwave fixation. According to the invention there is used a novel thermoplastic developer comprising of two components. The first component contains a dielectric material which is able to absorb microwave and generate heat by dielectric loss. The second component contains magnetic loss exothermic material. The microwave absorbing power of the first component is improved by heating the first component with heat generated from the second component.

  10. [Treatment in spondylolisthesis with a dynamic percutaneous lumbar external fixator. A three year experience].

    PubMed

    Carbajal, Braulio Hernández

    2008-01-01

    Degenerative spondylolisthesis is due to long time instability between segments, caused by ligament laxity. This originates subluxation, displacement and foramina stenosis with consequent root compression. It is frequent in L4-L5 in 50 year and older women. The objective of this work is to present a minimally invasive procedure for the treatment of spondylolisthesis, with a dynamic external fixator for percutaneous arthrodesis stabilization.

  11. Corrugated cover plate for flat plate collector

    DOEpatents

    Hollands, K. G. Terry; Sibbitt, Bruce

    1978-01-01

    A flat plate radiant energy collector is providing having a transparent cover. The cover has a V-corrugated shape which reduces the amount of energy reflected by the cover away from the flat plate absorber of the collector.

  12. Do Fixation Cues Ensure Fixation Accuracy in Split-Fovea Studies of Word Recognition?

    ERIC Educational Resources Information Center

    Jordan, Timothy R.; Paterson, Kevin B.; Kurtev, Stoyan; Xu, Mengyun

    2009-01-01

    Many studies have claimed that hemispheric processing is split precisely at the foveal midline and so place great emphasis on the precise location at which words are fixated. These claims are based on experiments in which a variety of fixation procedures were used to ensure fixation accuracy but the effectiveness of these procedures is unclear. We…

  13. Growth Plate Fractures

    MedlinePlus

    .org Growth Plate Fractures Page ( 1 ) The bones of children and adults share many of the same risks for injury. But because they ... to a unique injury called a growth plate fracture. Growth plates are areas of cartilage located near ...

  14. Proximal Humerus Fracture Plating Through the Extended Anterolateral Approach.

    PubMed

    Gardner, Michael J

    2016-08-01

    Several approaches to the proximal humerus for fracture fixation are possible. The traditional utilitarian approach to the shoulder, the deltopectoral, has distinct disadvantages when performing fracture reduction and locked plating. The anterolateral acromial approach exploits the intermuscular plane between the anterior and middle heads of the deltoid. After identifying the position of the axillary nerve as it crosses this interval, fracture reduction and fixation is performed. Direct access to both the greater and the lesser tuberosities is facilitated. The cancellous surface of the humeral head fragment provides an excellent surface for direct manipulation without further endangering the extraosseous soft tissue attachments.

  15. Odontoid compression of the brainstem without basilar impression-- "odontoid invagination".

    PubMed

    Kyoshima, Kazuhiko; Kakizawa, Yukinari; Tokushige, Kazuo; Akaishi, Kotaro; Kanaji, Miki; Kuroyanagi, Takayuki

    2005-06-01

    We report five patients with odontoid invagination, in which the odontoid process bulges upward into the foramen magnum and compresses the brainstem without deformity of the occipital bone. Two patients had a craniovertebral abnormality associated with Chiari malformation without instability of the craniovertebral junction (stable odontoid invagination). The other three patients had dislocation of the craniovertebral junction due to iatrogenic destruction of the occipital condyle, rheumatoid arthritis or an anomaly of C2 (unstable odontoid invagination). Patients with stable odontoid invagination underwent a transoral odontoidectomy followed by occipitocervical fixation. Those with unstable odontoid invagination underwent cervical traction followed by posterior fixation in reducible cases, while in irreducible cases odontoidectomy with subsequent occipitocervical fixation was performed. Decompression of the neuraxis together with symptomatic improvement was achieved in all patients and none became unstable or developed new symptoms during follow-up ranging from 3 to 15 years.

  16. ADVANCED RECIPROCATING COMPRESSION TECHNOLOGY (ARCT)

    SciTech Connect

    Danny M. Deffenbaugh; Klaus Brun; Ralph E. Harris; J. Pete Harrell; Robert J. Mckee; J. Jeffrey Moore; Steven J. Svedeman; Anthony J. Smalley; Eugene L. Broerman; Robert A Hart; Marybeth G. Nored; Ryan S. Gernentz; Shane P. Siebenaler

    2005-12-01

    . Retrofit technologies that address the challenges of slow-speed integral compression are: (1) optimum turndown using a combination of speed and clearance with single-acting operation as a last resort; (2) if single-acting is required, implement infinite length nozzles to address nozzle pulsation and tunable side branch absorbers for 1x lateral pulsations; and (3) advanced valves, either the semi-active plate valve or the passive rotary valve, to extend valve life to three years with half the pressure drop. This next generation of slow-speed compression should attain 95% efficiency, a three-year valve life, and expanded turndown. New equipment technologies that address the challenges of large-horsepower, high-speed compression are: (1) optimum turndown with unit speed; (2) tapered nozzles to effectively reduce nozzle pulsation with half the pressure drop and minimization of mechanical cylinder stretch induced vibrations; (3) tunable side branch absorber or higher-order filter bottle to address lateral piping pulsations over the entire extended speed range with minimal pressure drop; and (4) semi-active plate valves or passive rotary valves to extend valve life with half the pressure drop. This next generation of large-horsepower, high-speed compression should attain 90% efficiency, a two-year valve life, 50% turndown, and less than 0.75 IPS vibration. This program has generated proof-of-concept technologies with the potential to meet these ambitious goals. Full development of these identified technologies is underway. The GMRC has committed to pursue the most promising enabling technologies for their industry.

  17. Fuel cell separator with compressible sealing flanges

    DOEpatents

    Mientek, Anthony P.

    1985-04-30

    A separator for separating adjacent fuel cells in a stack of such cells includes a flat, rectangular, gas-impermeable plate disposed between adjacent cells and having two opposite side margins thereof folded back over one side of the plate to form two first seal flanges and having the other side margins thereof folded back over the opposite side of the plate to form two second seal flanges, each of the seal flanges cooperating with the plate to define a channel in which is disposed a resiliently compressible stack of thin metal sheets. The two first seal flanges cooperate with the electrolyte matrix of one of the cells to form a gas-impermeable seal between an electrode of the one cell and one of two reactant gas manifolds. The second seal flanges cooperate with the electrolyte matrix of the other cell for forming a gas-impermeable seal between an electrode of the other cell and the other of the two reactant gas manifolds. The seal flanges cooperate with the associated compressible stacks of sheets for maintaining a spacing between the plate and the electrolyte matrices while accommodating variation of that spacing.

  18. Fuel cell separator with compressible sealing flanges

    DOEpatents

    Mientek, A.P.

    1984-03-30

    A separator for separating adjacent fuel cells in a stack of such cells includes a flat, rectangular, gas-impermeable plate disposed between adjacent cells and having two opposite side margins thereof folded back over one side of the plate to form two first seal flanges and having the other side margins thereof folded back over the opposite side of the plate to form two second seal flanges, each of the seal flanges cooperating with the plate to define a channel in which is disposed a resiliently compressible stack of thin metal sheets. The two first seal flanges cooperate with the electrolyte matrix of one of the cells to form a gas-impermeable seal between an electrode of the one cell and one of two reactant gas manifolds. The second seal flanges cooperate with the electrolyte matrix of the other cell for forming a gas-impermeable seal between an electrode of the other cell and the other of the two reactant gas manifolds. The seal flanges cooperate with the associated compressible stacks of sheets for maintaining a spacing between the plate and the electrolyte matrices while accommodating variation of that spacing.

  19. Characterization of Tri-lab Tantalum Plate.

    SciTech Connect

    Buchheit, Thomas E.; Cerreta, Ellen K.; Deibler, Lisa Anne; Chen, Shu-Rong; Michael, Joseph R.

    2014-09-01

    This report provides a detailed characterization Tri-lab Tantalum (Ta) plate jointly purchased from HCStark Inc. by Sandia, Los Alamos and Lawrence Livermore National Laboratories. Data in this report was compiled from series of material and properties characterization experiments carried out at Sandia (SNL) and Los Alamos (LANL) Laboratories through a leveraged effort funded by the C2 campaign. Results include microstructure characterization detailing the crystallographic texture of the material and an increase in grain size near the end of the rolled plate. Mechanical properties evaluations include, compression cylinder, sub-scale tension specimen, micohardness and instrumented indentation testing. The plate was found to have vastly superior uniformity when compare with previously characterized wrought Ta material. Small but measurable variations in microstructure and properties were noted at the end, and at the top and bottom edges of the plate.

  20. Multiscale modeling of growth plate cartilage mechanobiology.

    PubMed

    Gao, Jie; Williams, John L; Roan, Esra

    2017-04-01

    Growth plate chondrocytes are responsible for bone growth through proliferation and differentiation. However, the way they experience physiological loads and regulate bone formation, especially during the later developmental phase in the mature growth plate, is still under active investigation. In this study, a previously developed multiscale finite element model of the growth plate is utilized to study the stress and strain distributions within the cartilage at the cellular level when rapidly compressed to 20 %. Detailed structures of the chondron are included in the model to examine the hypothesis that the same combination of mechanoregulatory signals shown to maintain cartilage or stimulate osteogenesis or fibrogenesis in the cartilage anlage or fracture callus also performs the same function at the cell level within the chondrons of growth plate cartilage. Our cell-level results are qualitatively and quantitatively in agreement with tissue-level theories when both hydrostatic cellular stress and strain are considered simultaneously in a mechanoregulatory phase diagram similar to that proposed at the tissue level by Claes and Heigele for fracture healing. Chondrocytes near the reserve/proliferative zone border are subjected to combinations of high compressive hydrostatic stresses ([Formula: see text] MPa), and cell height and width strains of [Formula: see text] to [Formula: see text] respectively, that maintain cartilage and keep chondrocytes from differentiating and provide conditions favorable for cell division, whereas chondrocytes closer to the hypertrophic/calcified zone undergo combinations of lower compressive hydrostatic stress ([Formula: see text] MPa) and cell height and width strains as low as [Formula: see text] to +4 %, respectively, that promote cell differentiation toward osteogenesis; cells near the outer periphery of the growth plate structure experience a combination of low compressive hydrostatic stress (0 to [Formula: see text] MPa) and

  1. Biochemical Approaches to Improved Nitrogen Fixation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Improving symbiotic nitrogen fixation by legumes has emerged again as an important topic on the world scene due to the energy crisis and lack of access to nitrogen fertilizer in developing countries. We have taken a biochemical genomics approach to improving symbiotic nitrogen fixation in legumes. L...

  2. Treatment of Early Post-Op Wound Infection after Internal Fixation

    DTIC Science & Technology

    2014-10-01

    having difficulty maintaining equipoise when prescribing antibiotics . Informational slides have been developed for the sites to use to present the study...to their Infectious Disease teams to assist with this problem. 15. SUBJECT TERMS PO, IV, Antibiotics , plate, fixation, infection 16. SECURITY...and either: (Group 1) operative debridement and PO antibiotic treatment for 6 weeks; or (Group 2) operative debridement and IV antibiotics for 6

  3. Clavicle fractures in 2010: sling/swathe or open reduction and internal fixation?

    PubMed

    McKee, Michael D

    2010-04-01

    Clavicle fractures are common, and they comprise close to 3% of all fractures seen in fracture clinics. Midshaft fractures account for approximately 80% of all clavicle fractures and are the focus of this article. In carefully selected cases primary plate fixation of displaced midshaft clavicle fractures improves outcome, results in earlier return to function, and reduces the nonunion and symptomatic malunion rate significantly compared with nonoperative treatment.

  4. Benchtop comparison of a novel dynamic compression screw to a standard cortical screw: compression integrity and gap size over time during simulated resorption.

    PubMed

    Kinmon, Kyle; Garzon, Desiree; Tacktill, Jordan; Vassello, Wayne

    2013-06-01

    Literature reports the incidence of failed isolated foot and ankle fusions as up to 23%. A contributing factor is the natural bone resorption, which occurs resulting in loss of compression and gapping at the fusion site when standard static compression plates and screws are used. However, an innovative dynamic compression screw may provide lasting compression despite resorption. This benchtop study shows that the FxDEVICES spring-loaded dynamic POGO screw maintains more compression and more consistent compression rate during simulated resorption, as compared with a standard compression screw. The novel screw maintained much greater compression strength within the first millimeter of simulated resorption (13.57 vs 4.38 lb) and maintained greater compression strength at the test completion (1.14 vs 0 lb). The novel screw revealed a more consistent resorption rate over the duration of the simulation. Clinically, this may result in more stability and improved fusion rates.

  5. Do fixation cues ensure fixation accuracy in split-fovea studies of word recognition?

    PubMed

    Jordan, Timothy R; Paterson, Kevin B; Kurtev, Stoyan; Xu, Mengyun

    2009-07-01

    Many studies have claimed that hemispheric processing is split precisely at the foveal midline and so place great emphasis on the precise location at which words are fixated. These claims are based on experiments in which a variety of fixation procedures were used to ensure fixation accuracy but the effectiveness of these procedures is unclear. We investigated this issue using procedures matched to the original studies and an eye-tracker to monitor the locations actually fixated. Four common types of fixation cues were used: cross, two vertical gapped lines, two vertical gapped lines plus a secondary task in which a digit was presented at the designated fixation point, and a dot. Accurate fixations occurred on <35% of trials for all fixation conditions. Moreover, despite the usefulness often attributed to a secondary task, no increase in fixation accuracy was produced in this condition. The indications are that split-fovea theory should not assume that fixation of specified locations occurs in experiments without appropriate eye-tracking control or, indeed, that consistent fixation of specified locations is plausible under normal conditions of word recognition.

  6. Minimally invasive plate osteosynthesis: tibia and fibula.

    PubMed

    Beale, Brian S; McCally, Ryan

    2012-09-01

    Fractures of the tibia and fibula are common in dogs and cats and occur most commonly as a result of substantial trauma. Tibial fractures are often amenable to repair using the minimally invasive plate osteosynthesis (MIPO) technique because of the minimal soft tissue covering of the tibia and relative ease of indirect reduction and application of the implant system on the tibia. Treatment of tibial fractures by MIPO has been found to reduce surgical time, reduce the time for fracture healing, and decrease patient morbidity, while at the same time reducing complications compared with traditional open reduction and internal fixation.

  7. Eighth international congress on nitrogen fixation. Final program

    SciTech Connect

    Not Available

    1990-12-31

    This volume contains the proceedings of the Eighth International Congress on Nitrogen Fixation held May 20--26, 1990 in Knoxville, Tennessee. The volume contains abstracts of individual presentations. Sessions were entitled Recent Advances in the Chemistry of Nitrogen Fixation, Plant-microbe Interactions, Limiting Factors of Nitrogen Fixation, Nitrogen Fixation and the Environment, Bacterial Systems, Nitrogen Fixation in Agriculture and Industry, Plant Function, and Nitrogen Fixation and Evolution.

  8. Locking Plate Alone versus in Combination with Two Crossed Kirschner Wires for Fifth Metacarpal Neck Fracture

    PubMed Central

    Zhu, Hongyi; Xu, Zhengyu; Wei, Haifeng; Zheng, Xianyou

    2017-01-01

    Fracture of fifth metacarpal neck commonly requires open reduction and internal fixation. However, the current methods of internal fixation in fifth metacarpal neck fractures remain unsatisfactory. Patients with fractures of fifth metacarpal neck received open reduction and internal fixation with either locking plate in combination with two crossed Kirschner wires (K-wires) or locking plate alone were evaluated for the clinical outcomes. Clinical outcomes included grip strength, Michigan hand outcomes questionnaire (MHQ), final angulation and range of motion (ROM) one year after treatment. The averages of MHQ scores, final angulation and ROM of fifth metacarpophalangeal joint of plate with K-wire group were more superior to those of plate group (MHQ 96.7 versus 86.6, final angulation 11.8 versus 23.6, ROM 83.3 versus 72.2). The grip strength had no significant difference between two groups. Locking plate in combination with two crossed K-wires is a more optimal method of fixation compared with locking plate alone. PMID:28378776

  9. Delayed Foreign Body Reaction Caused by Bioabsorbable Plates Used for Maxillofacial Fractures

    PubMed Central

    Jeon, Hong Bae; Gu, Ja Hea; Oh, Sang Ah

    2016-01-01

    Background Bioabsorbable plates and screws are commonly used to reduce maxillofacial bones, particularly in pediatric patients because they degrade completely without complications after bone healing. In this study, we encountered eight cases of a delayed foreign body reaction after surgical fixation with bioabsorbable plates and screws. Methods A total of 234 patients with a maxillofacial fracture underwent surgical treatment from March 2006 to October 2013, in which rigid fixation was achieved with the Inion CPS (Inion, Tampere, Finland) plating system in 173 patients and Rapidsorb (Synthes, West Chester, PA, USA) in 61 patients. Their mean age was 35.2 years (range, 15-84 years). Most patients were stabilized with two- or three-point fixation at the frontozygomatic suture, infraorbital rim, and anterior wall of the maxilla. Results Complications occurred in eight (3.4%) of 234 patients, including palpable, fixed masses in six patients and focal swelling in two patients. The period from surgical fixation to the onset of symptoms was 9-23 months. Six patients with a mass underwent secondary surgery for mass removal. The masses contained fibrous tissue with a yellow, grainy, cloudy fluid and remnants of an incompletely degraded bioabsorbable plate and screws. Their histological findings demonstrated a foreign body reaction. Conclusions Inadequate degradation of bioabsorbable plates caused a delayed inflammatory foreign body reaction requiring secondary surgery. Therefore, it is prudent to consider the possibility of delayed complications when using bioabsorbable plates and surgeons must conduct longer and closer follow-up observations. PMID:26848444

  10. [Therapy progress of spinal cord compression by metastatic spinal tumor].

    PubMed

    Liu, Yao-sheng; He, Qi-zhen; Liu, Shu-bin; Jiang, Wei-gang; Lei, Ming-xing

    2016-01-01

    Metastatic epidural compression of the spinal cord is a significant source of morbidity in patients with systemic cancer. With improvment of oncotheray, survival period in the patients is improving and metastatic cord compression is en- countered increasingly often. Surgical management performed for early circumferential decompression for the spinal cord com- pression with spine instability, and spine reconstruction performed. Patients with radiosensitive tumours without spine instabili- ty, radiotherapy is an effective therapy. Spinal stereotactic radiosurgery and minimally invasive techniques, such as vertebro- plasty and kyphoplasty, percutaneous pedicle screw fixation, radiofrequency ablation are promising options for treatment of cer- tain selected patients with spinal metastases.

  11. Abnormal Fixational Eye Movements in Amblyopia

    PubMed Central

    Shaikh, Aasef G.; Otero-Millan, Jorge; Kumar, Priyanka; Ghasia, Fatema F.

    2016-01-01

    Purpose Fixational saccades shift the foveal image to counteract visual fading related to neural adaptation. Drifts are slow eye movements between two adjacent fixational saccades. We quantified fixational saccades and asked whether their changes could be attributed to pathologic drifts seen in amblyopia, one of the most common causes of blindness in childhood. Methods Thirty-six pediatric subjects with varying severity of amblyopia and eleven healthy age-matched controls held their gaze on a visual target. Eye movements were measured with high-resolution video-oculography during fellow eye-viewing and amblyopic eye-viewing conditions. Fixational saccades and drifts were analyzed in the amblyopic and fellow eye and compared with controls. Results We found an increase in the amplitude with decreased frequency of fixational saccades in children with amblyopia. These alterations in fixational eye movements correlated with the severity of their amblyopia. There was also an increase in eye position variance during drifts in amblyopes. There was no correlation between the eye position variance or the eye velocity during ocular drifts and the amplitude of subsequent fixational saccade. Our findings suggest that abnormalities in fixational saccades in amblyopia are independent of the ocular drift. Discussion This investigation of amblyopia in pediatric age group quantitatively characterizes the fixation instability. Impaired properties of fixational saccades could be the consequence of abnormal processing and reorganization of the visual system in amblyopia. Paucity in the visual feedback during amblyopic eye-viewing condition can attribute to the increased eye position variance and drift velocity. PMID:26930079

  12. 3D-FEM and histomorphology of mandibular reconstruction with the titanium functionally dynamic bridging plate.

    PubMed

    Schuller-Götzburg, P; Pleschberger, M; Rammerstorfer, F G; Krenkel, C

    2009-12-01

    Biomechanical investigation of the mandible is difficult due to the complex geometrical structure. A three-dimensional finite element model of the mandible and masticatory muscles was produced with approximately 23,000 hexahedral elements. On this model, mesial and distal portions of the jaw were resected and bridged with a buccal and/or caudally positioned bridging plate. The plate was fixed caudal or buccal to the mandible. The defect was left as it was or reconstructed with an exactly fitting transplant defined as bone. The jaw was loaded at a predefined point. The changes in stresses and deformations of bone, the transplant and the bridging plate were analysed. In the caudally positioned bridging plate, finite element analysis showed lesser stresses around the fixation screws of the bridging plate. During reconstruction of the lateral defect, the buccal (ramus)-caudal (corpus) position of the bridging plate showed fewer stresses and deformations than purely buccal positioning. The caudal position of the bridging plate has biomechanical advantages and facilitates fixation of the plate, and fixation of a bone graft on the jaw stumps. Histomorphological investigations, 12 weeks and 7 years after reconstruction, show partial osseous integration or transformation of autologous iliac crest transplants.

  13. Intraoperative Periprosthetic Femur Fracture: A Biomechanical Analysis of Cerclage Fixation.

    PubMed

    Frisch, Nicholas B; Charters, Michael A; Sikora-Klak, Jakub; Banglmaier, Richard F; Oravec, Daniel J; Silverton, Craig D

    2015-08-01

    Intraoperative periprosthetic femur fracture is a known complication of total hip arthroplasty (THA) and a variety of cerclage systems are available to manage these fractures. The purpose of this study was to examine the in situ biomechanical response of cerclage systems for fixation of periprosthetic femur fractures that occur during cementless THA. We compared cobalt chrome (CoCr) cables, synthetic cables, monofilament wires and hose clamps under axial compressive and torsional loading. Metallic constructs with a positive locking system performed the best, supporting the highest loads with minimal implant subsidence (both axial and angular) after loading. Overall, the CoCr cable and hose clamp had the highest construct stiffness and least reduction in stiffness with increased loading. They were not demonstrably different from each other.

  14. Sputtering and ion plating

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The proceedings of a conference on sputtering and ion plating are presented. Subjects discussed are: (1) concepts and applications of ion plating, (2) sputtering for deposition of solid film lubricants, (3) commercial ion plating equipment, (4) industrial potential for ion plating and sputtering, and (5) fundamentals of RF and DC sputtering.

  15. Microbunching and RF Compression

    SciTech Connect

    Venturini, M.; Migliorati, M.; Ronsivalle, C.; Ferrario, M.; Vaccarezza, C.

    2010-05-23

    Velocity bunching (or RF compression) represents a promising technique complementary to magnetic compression to achieve the high peak current required in the linac drivers for FELs. Here we report on recent progress aimed at characterizing the RF compression from the point of view of the microbunching instability. We emphasize the development of a linear theory for the gain function of the instability and its validation against macroparticle simulations that represents a useful tool in the evaluation of the compression schemes for FEL sources.

  16. Dinitrogen fixation in aphotic oxygenated marine environments

    PubMed Central

    Rahav, Eyal; Bar-Zeev, Edo; Ohayon, Sarah; Elifantz, Hila; Belkin, Natalia; Herut, Barak; Mulholland, Margaret R.; Berman-Frank, Ilana

    2013-01-01

    We measured N2 fixation rates from oceanic zones that have traditionally been ignored as sources of biological N2 fixation; the aphotic, fully oxygenated, nitrate (NO−3)-rich, waters of the oligotrophic Levantine Basin (LB) and the Gulf of Aqaba (GA). N2 fixation rates measured from pelagic aphotic waters to depths up to 720 m, during the mixed and stratified periods, ranged from 0.01 nmol N L−1 d−1 to 0.38 nmol N L−1 d−1. N2 fixation rates correlated significantly with bacterial productivity and heterotrophic diazotrophs were identified from aphotic as well as photic depths. Dissolved free amino acid amendments to whole water from the GA enhanced bacterial productivity by 2–3.5 fold and N2 fixation rates by ~2-fold in samples collected from aphotic depths while in amendments to water from photic depths bacterial productivity increased 2–6 fold while N2 fixation rates increased by a factor of 2 to 4 illustrating that both BP and heterotrophic N2 fixation were carbon limited. Experimental manipulations of aphotic waters from the LB demonstrated a significant positive correlation between transparent exopolymeric particle (TEP) concentrations and N2 fixation rates. This suggests that sinking organic material and high carbon (C): nitrogen (N) micro-environments (such as TEP-based aggregates or marine snow) could support high heterotrophic N2 fixation rates in oxygenated surface waters and in the aphotic zones. Indeed, our calculations show that aphotic N2 fixation accounted for 37 to 75% of the total daily integrated N2 fixation rates at both locations in the Mediterranean and Red Seas with rates equal or greater to those measured from the photic layers. Moreover, our results indicate that that while N2 fixation may be limited in the surface waters, aphotic, pelagic N2 fixation may contribute significantly to new N inputs in other oligotrophic basins, yet it is currently not included in regional or global N budgets. PMID:23986748

  17. Compressed gas manifold

    DOEpatents

    Hildebrand, Richard J.; Wozniak, John J.

    2001-01-01

    A compressed gas storage cell interconnecting manifold including a thermally activated pressure relief device, a manual safety shut-off valve, and a port for connecting the compressed gas storage cells to a motor vehicle power source and to a refueling adapter. The manifold is mechanically and pneumatically connected to a compressed gas storage cell by a bolt including a gas passage therein.

  18. "False" migration of rigid fixation appliances in pediatric craniofacial surgery.

    PubMed

    Papay, F A; Hardy, S; Morales, L; Walker, M; Enlow, D

    1995-07-01

    Osseous fixation techniques have been widely used to provide rigid stabilization in the craniofacial skeleton. Reported sequelae of its usage has been limited to palpation of the screw-plate system and radiological imaging artifacts. Over the past 3 years we have identified miniplates, microplates, and wire sutures on the inner cranial table of the growing child. The observation of "false" migration of these appliances has provided the impetus to review these patients in more detail. Twenty patients underwent secondary cranial remodeling within a two-year period; 7 of these patients were seen to have "false" migration. There were no untoward sequelae in removal of these appliances, and no adverse neurological symptoms were seen.

  19. Kennedy Space Center Fixation Tube (KFT)

    NASA Technical Reports Server (NTRS)

    Richards, Stephanie E.; Levine, Howard G.; Romero, Vergel

    2016-01-01

    Experiments performed on the International Space Station (ISS) frequently require the experimental organisms to be preserved until they can be returned to earth for analysis in the appropriate laboratory facility. The Kennedy Fixation Tube (KFT) was developed to allow astronauts to apply fixative, chemical compounds that are often toxic, to biological samples without the use of a glovebox while maintaining three levels of containment (Fig. 1). KFTs have been used over 200 times on-orbit with no leaks of chemical fixative. The KFT is composed of the following elements: a polycarbonate main tube where the fixative is loaded preflight, the sample tube where the plant or other biological specimens is placed during operations, the expansion plug, actuator, and base plug that provides fixative containment (Fig. 2). The main tube is pre-filled with 25 mL of fixative solution prior to flight. When actuated, the specimen contained within the sample tube is immersed with approximately 22 mL (+/- 2 mL) of the fixative solution. The KFT has been demonstrated to maintain its containment at ambient temperatures, 4degC refrigeration and -100 C freezing conditions.

  20. Accuracy of distal radius positioning using an anatomical plate.

    PubMed

    Vroemen, Joy C; Dobbe, Johannes G G; Sierevelt, Inger N; Strackee, Simon D; Streekstra, Geert J

    2013-04-01

    Over the past decade, several anatomical plates have been introduced to improve the result of open reduction and internal fixation of the distal radius. Using 3-dimensional imaging techniques, the authors studied the accuracy and reproducibility of distal radius positioning using anatomical plates.Distal radius fractures and the correction of these fractures were simulated with plastic bone models of radii. The authors simulated a defect by removing an arbitrary wedge shape from the artificial radii. Two surgeons corrected these fractures by placing 2 anatomical plate types according to the plate manufacturers' instructions. The residual positioning errors of the distal segment in relation to the unaffected radii were determined using 3-dimensional imaging and were compared with naturally occurring bilateral radius differences in healthy individuals. In many cases, positioning does not agree with differences based on bilateral asymmetry in healthy patients.This study indicated the accuracy of anatomical plates. Positioning an anatomical plate may lead to considerable residual errors in individual patients. Volar distal radius plate shapes differ among plate manufacturers. Therefore, one plate may perform better than another in an individual.

  1. A parametric analysis of fixation post shape in tibial knee prostheses.

    PubMed

    Au, Anthony G; Liggins, Adrian B; Raso, V James; Amirfazli, A

    2005-03-01

    A primary concern of total knee replacement (TKR) is aseptic loosening of the tibial component, which may be caused by shielding of mechanical stresses in the bone and may require subsequent revision surgery. A three-dimensional (3D) finite element (FE) model has been developed to study bone and interface stresses for four different tibial prosthesis designs. The model described here incorporates orthotropic and heterogeneous bone properties with physiologically representative loading conditions. Results from this model indicate that stress distribution is affected by the incorporation of anisotropy and spatial variation of bone properties. All bone properties were mapped from published data to characterize their anisotropy and heterogeneity. Physiological loading was incorporated by mapping experimentally determined contact patterns. Convergence testing was performed to ensure model accuracy. In terms of interface forces, a tapered post decreased post shear while slightly increasing post compression compared to a cylindrical post; a post of elliptical cross-section increased post shear and decreased post compression. In terms of cancellous bone stress, tapered and elliptical posts both relieved compression compared to a cylindrical post, while a tapered post also produced increased peripheral stress. The inclusion of medial and lateral pegs in addition to a central fixation post caused localized stress shielding in the periphery of the pegs. In general, all implant models caused a reduction of cancellous bone stress plus high compression beneath the central fixation posts.

  2. Volcano spacing and plate rigidity

    SciTech Connect

    Brink, U. )

    1991-04-01

    In-plane stresses, which accompany the flexural deformation of the lithosphere under the load adjacent volcanoes, may govern the spacing of volcanoes in hotspot provinces. Specifically, compressive stresses in the vicinity of a volcano prevent new upwelling in this area, forcing a new volcano to develop at a minimum distance that is equal to the distance in which the radial stresses change from compressional to tensile (the inflection point). If a volcano is modeled as a point load on a thin elastic plate, then the distance to the inflection point is proportional to the thickness of the plate to the power of 3/4. Compilation of volcano spacing in seven volcanic groups in East Africa and seven volcanic groups of oceanic hotspots shows significant correlation with the elastic thickness of the plate and matches the calculated distance to the inflection point. In contrast, volcano spacing in island arcs and over subduction zones is fairly uniform and is much larger than predicted by the distance to the inflection point, reflecting differences in the geometry of the source and the upwelling areas.

  3. Steady compression characteristics of laminated MRE isolator

    NASA Astrophysics Data System (ADS)

    Wahab, N. A. A.; Mazlan, S. A.; Ubaidillah; Sharif, A. H. R.; Kamaruddin, S.

    2016-11-01

    This paper focused on an experimental setup on laminated magnetorheological elastomer (MRE) isolator under steady state compression test. An isotropic type natural rubber (NR) based MRE were fabricated and layered with a steel plate to form a multilayer sandwich structure adopted from the conventional laminated rubber bearing design. A set of static compression test was conducted to explore the potential of semi-active laminated MRE isolator in field-dependent stiffness properties. Stress versus strain relationship was assessed under different magnetic fields application. Based on the examination, the stress altered as the application of magnetic fields. Consequently, the effective stiffness of isolator also influenced by the magnetic fields induction. The experimental results show that the proposed laminated MRE isolator can effectively alter the compression stiffness up to the 14.56%. The preliminary results have confirmed the tunability of the semi-active laminated MRE isolator in which it would be beneficial for improving building isolator in general.

  4. Shock compression properties of silicon carbide

    SciTech Connect

    Grady, D.E.; Kipp, M.E.

    1993-07-01

    An investigation of the shock compression and release properties of silicon carbide ceramic has been performed. A series of planar impact experiments has been completed in which stationary target discs of ceramic were struck by plates of either similar ceramic or other appropriate material at velocities up to 2.2 km/s with a propellant gun facility. The particle velocity history at the interface between the back of the target ceramic and a lithium-fluoride window material was measured with laser velocity interferometry (VISAR). Impact stresses achieved in these experiments range between about 10 and 50 GPa. Numerical solutions and analytic methods were used to determine the dynamic compression and release stress-strain behavior of the ceramic. Further analysis of the data was performed to determine dynamic strength and compressibility properties of silicon carbide.

  5. The compressive strengths of ice cubes of different sizes

    SciTech Connect

    Kuehn, G.A.; Schulson, E.M.; Jones, D.E.; Zhang, J. . Thayer School of Engineering)

    1993-05-01

    Cubes of side length from 10 to 150 mm were prepared from freshwater granular ice of about 1 mm grain size and then compressed uniaxially to failure at [minus]10 C. In addition to size, the variables were strain rate (10[sup [minus]5] s[sup [minus]1] and 10[sup [minus]2] s[sup [minus]1]) and boundary conditions (ground brass plates, ground and polished brass plates, and brass brushes). The results showed that over the range investigated, size is not an important factor when considering the ductile compressive strength of ice. It also appears that size is not a factor when considering the brittle compressive failure strength under more ideal loading conditions. However, under less ideal conditions where perturbations on the loading surface may be significant, the brittle compressive strength decreases as the size of cube increases. In this case, the effect is attributed to nonsimultaneous failure.

  6. Less is more: lag screw only fixation of lateral malleolar fractures

    PubMed Central

    O’Shea, Kieran; Burke, Tom

    2006-01-01

    Displaced fractures of the lateral malleolus are typically treated with plate osteosynthesis with or without the use of lag screws, and immobilisation in a plaster cast for up to 6 weeks. Fixation through a smaller incision with less metal, such as lag screw only fixation, would theoretically lead to decreased infection rates and less irritation caused by hardware. The purpose of this study was to evaluate the benefits and success of lag screw only fixation of the lateral malleolus in non-comminuted oblique fractures of the lateral malleolus. A total of 25 patients who had non-comminuted unstable oblique fractures of their lateral malleolus that had been surgically fixed with lag screws only were retrospectively evaluated. All patients were younger than 60 years of age. Evaluation of the success of fixation, complications, resultant mobility and patient satisfaction was based on information gathered from chart reviews, X-ray findings and a standardised questionnaire based on the AOFAS Foot and Ankle Outcomes Questionnaire. These results were compared to an age-matched group of 25 consecutive patients treated with plate osteosynthesis. Of the 25 patients fixed with lag screws, nine had an unstable fracture of the lateral malleolus only, ten were bimalleolar fractures and six were trimalleolar. Eighteen patients were treated with two lag screws, and seven were treated with three lag screws. The bi- and trimalleolar fractures were treated with standard partially threaded cancellous screws. None of the lag screw-only group lost reduction. There were no documented wound infections in the lag screw group as compared to three deep infections in the plate group. Lag screw-only patients reported no palpable hardware as compared to 50% of the plate group. AOFAS scores at a mean of 12 months post-operative were similar in both groups. Lag screw only fixation of the lateral malleolus is a safe and effective method that has a number of advantages over plate osteosynthesis

  7. The biomechanical advantages of bilateral lumbo-iliac fixation in unilateral comminuted sacral fractures without sacroiliac screw safe channel

    PubMed Central

    Song, Wenhao; Zhou, Dongsheng; He, Yu

    2016-01-01

    Abstract Background: The aim of this study was to compare the biomechanical characteristics between bilateral and unilateral lumbo-iliac fixation in unilateral comminuted sacral fractures (USF) by finite element analysis. Methods: A 3-dimensional finite element model of unilateral sacral fractures was simulated. Three kinds of implants were instrumented into the model, including the unilateral lumbopelvic fixation (ULF), bilateral lumbopelvic fixation (BLF), and unilateral iliac fixation with bilateral lumbar pedicle screws (UBF). Loads of compression and rotation were distributed to the superior endplate of L3. To evaluate the biomechanical properties, the construct stiffness, the micromotion of the fractures, the stress distribution of implants, and the balance of hemilumbar vertebra are recorded and analyzed. Results: The highest construct stiffness was provided by BLF. In BLF model, the displacement between iliums was only 0.009 mm (compressional) and 0.001 mm (rotational), which was less than that under normal condition (0.02 mm). The maximum von Misses stress of implants appeared on the UBF. By using unilateral fixation, the L4 endured obvious imbalance on bilateral hemivertebra. A marked difference was exposed in BLF and UBF models, and the equilibrium of stress and activity was shown. Conclusion: From the finite element view, the stability of ULF is insufficient to reconstruct the posterior pelvic ring. Furthermore, the unilateral fixation may lead to imbalance of lumbar vertebra and pelvis. On the contrary, the BLF can provide satisfied stability and lumbar balance. PMID:27749563

  8. Fixture For Crush Testing Of Composite Plates

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Lavoie, J. Andre; Morton, John

    1995-01-01

    Test fixture holds composite-material (matrix/fiber) plate specimens for crush testing in universal compression-testing machine to determine energy absorption characteristics of composite material system and laminate. Accommodates specimens of two different sizes; 6 by 4 by 0.16 in. and 3 by 2 by 0.08 in., designated as full scale and half scale, respectively. Contributes to development of more crashworthy composite-material structural components of aircraft.

  9. High-performance compression of astronomical images

    NASA Technical Reports Server (NTRS)

    White, Richard L.

    1993-01-01

    Astronomical images have some rather unusual characteristics that make many existing image compression techniques either ineffective or inapplicable. A typical image consists of a nearly flat background sprinkled with point sources and occasional extended sources. The images are often noisy, so that lossless compression does not work very well; furthermore, the images are usually subjected to stringent quantitative analysis, so any lossy compression method must be proven not to discard useful information, but must instead discard only the noise. Finally, the images can be extremely large. For example, the Space Telescope Science Institute has digitized photographic plates covering the entire sky, generating 1500 images each having 14000 x 14000 16-bit pixels. Several astronomical groups are now constructing cameras with mosaics of large CCD's (each 2048 x 2048 or larger); these instruments will be used in projects that generate data at a rate exceeding 100 MBytes every 5 minutes for many years. An effective technique for image compression may be based on the H-transform (Fritze et al. 1977). The method that we have developed can be used for either lossless or lossy compression. The digitized sky survey images can be compressed by at least a factor of 10 with no noticeable losses in the astrometric and photometric properties of the compressed images. The method has been designed to be computationally efficient: compression or decompression of a 512 x 512 image requires only 4 seconds on a Sun SPARCstation 1. The algorithm uses only integer arithmetic, so it is completely reversible in its lossless mode, and it could easily be implemented in hardware for space applications.

  10. Predicting the optical behaviour of shock compressed dielectrics

    NASA Astrophysics Data System (ADS)

    Tear, Gareth R.; Proud, William G.

    2017-01-01

    An anisotropic photoelastic model for predicting the optical properties of shock compressed anisotropic dielectrics has been developed for the purpose of investigating the effect of experimental tilt. This model has been used to predict the expected effect of impact and crystallographic tilt on birefringence measurements for a plate impact experiment. It was found that the expected systematic error to the birefringence measurement caused by experimental tilt was likely to be negligible. Predictions for various common anisotropic minerals compressed along the a-axis are also presented and the model is compared to experimental plate impact data from PMMA and sapphire.

  11. Neural correlates of fixation duration in natural reading: Evidence from fixation-related fMRI.

    PubMed

    Henderson, John M; Choi, Wonil; Luke, Steven G; Desai, Rutvik H

    2015-10-01

    A key assumption of current theories of natural reading is that fixation duration reflects underlying attentional, language, and cognitive processes associated with text comprehension. The neurocognitive correlates of this relationship are currently unknown. To investigate this relationship, we compared neural activation associated with fixation duration in passage reading and a pseudo-reading control condition. The results showed that fixation duration was associated with activation in oculomotor and language areas during text reading. Fixation duration during pseudo-reading, on the other hand, showed greater involvement of frontal control regions, suggesting flexibility and task dependency of the eye movement network. Consistent with current models, these results provide support for the hypothesis that fixation duration in reading reflects attentional engagement and language processing. The results also demonstrate that fixation-related fMRI provides a method for investigating the neurocognitive bases of natural reading.

  12. Finite element modeling of stress in the Nazca plate - Driving forces and plate boundary earthquakes

    NASA Technical Reports Server (NTRS)

    Richardson, R. M.

    1978-01-01

    The state of stress within the Nazca plate due to plate driving forces and large plate boundary earthquakes has been analyzed by applying a finite element method using the wave front solution technique to models of the intraplate stress field in a single plate using a refined grid. Although only static elastic models have been explicitly calculated, certain limiting cases of an elastic plate over a viscous asthenosphere were also treated. A state of nearly east-west compression inferred from the source mechanism of thrust earthquakes in the interior of the plate requires ridge pushing forces. The net pulling force on the oceanic plate by the subducted slab has a maximum value comparable to pushing forces. The estimated horizontal deviatoric stress in intraplate regions, based on potential forces associated with the ridge, is on the order of a few hundred bars. The intraplate stress field in the region of the 1960 earthquake may change by a few tens of bars at most once the asthenosphere has relaxed, with changes on the order of one bar occurring at greater distances into the plate. The changes in the intraplate stress field are probably not noticeable unless the lithosphere is near failure.

  13. Effects of rigidity of an internal fixation device. A comprehensive biomechanical investigation.

    PubMed

    Goel, V K; Lim, T H; Gwon, J; Chen, J Y; Winterbottom, J M; Park, J B; Weinstein, J N; Ahn, J Y

    1991-03-01

    Internal fixation with instrumentation often accompanies surgical fusion to augment spinal stability, provide temporary fixation while the surgical fusion mass unites, and enhance postoperative mobilization of a patient. Some surgeons, however, feel that the existing plate-screw designs are too rigid and are the primary cause of "iatrogenic" adverse effects clinically observed. A three-part study, involving in vitro experimental protocol, analytical finite-element-based models, and an in vivo canine investigation, was undertaken to study the role of decreasing rigidity of a device on the biomechanical response of the stabilized segments. Two alternatives--the use of one variable screw placement (Steffee plate [unilateral, 1VSP model]) as opposed to two VSP plates (bilateral, 2VSP model) and two VSP plates with polymer washers placed in between the integral nut and plate (2MVSP model)--were considered for achieving a reduction in the rigidity of the conventional VSP system. The load-displacement data obtained from the in vitro experiments and the stress distributions within the stabilized and intact models predicted by the finite-element models revealed that the unilateral VSP system is less rigid and is likely to reduce stress shielding of the vertebral bodies compared with the 2VSP model. The undesirable effects associated with the use of the 1VSP plate system are the presence of coupled motions due to the inherent asymmetry and the likely inability to provide enough rigidity for decompression procedures requiring a complete excision of the disc. The use of two MVSP plates overcomes these deficiencies.(ABSTRACT TRUNCATED AT 250 WORDS)

  14. Mid-term functional outcome after the internal fixation of distal radius fractures

    PubMed Central

    2012-01-01

    Background Distal radius fracture is a common injury with a variety of operative and non-operative management options. There remains debate as to the optimal treatment for a given patient and fracture. Despite the popularity of volar locking plate fixation, there are few large cohort or long term follow up studies to justify this modality. Our aim was to report the functional outcome of a large number of patients at a significant follow up time after fixation of their distal radius with a volar locking plate. Methods 180 patients with 183 fractures and a mean age of 62.4 years were followed up retrospectively at a mean of 30 months (Standard deviation = 10.4). Functional assessment was performed using the Disabilities of the Arm, Shoulder and Hand (DASH) and modified MAYO wrist scores. Statistical analysis was performed to identify possible variables affecting outcome and radiographs were assessed to determine time to fracture union. Results The median DASH score was 2.3 and median MAYO score was 90 for the whole group. Overall, 133 patients (74%) had a good or excellent DASH and MAYO score. Statistical analysis showed that no specific variable including gender, age, fracture type, post-operative immobilisation or surgeon grade significantly affected outcome. Complications occurred in 27 patients (15%) and in 11 patients were major (6%). Conclusion This single centre large population series demonstrates good to excellent results in the majority of patients after volar locking plate fixation of the distal radius, with complication rates comparable to other non-operative and operative treatment modalities. On this basis we recommend this mode of fixation for distal radius fractures requiting operative intervention. PMID:22280557

  15. Ocular Fixation Abnormality in Patients with Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Shirama, Aya; Kanai, Chieko; Kato, Nobumasa; Kashino, Makio

    2016-01-01

    We examined the factors that influence ocular fixation control in adults with autism spectrum disorder (ASD) including sensory information, individuals' motor characteristics, and inhibitory control. The ASD group showed difficulty in maintaining fixation especially when there was no fixation target. The fixational eye movement characteristics of…

  16. When femoral fracture fixation fails: salvage options.

    PubMed

    Petrie, J; Sassoon, A; Haidukewych, G J

    2013-11-01

    Most hip fractures treated with modern internal fixation techniques will heal. However, failures occasionally occur and require revision procedures. Salvage strategies employed during revision are based on whether the fixation failure occurs in the femoral neck, or in the intertrochanteric region. Patient age and remaining bone stock also influence decision making. For fractures in young patients, efforts are generally focused on preserving the native femoral head via osteotomies and repeat internal fixation. For failures in older patients, some kind of hip replacement is usually selected. Disuse osteopenia, deformity, bone loss, and stress-risers from previous internal fixation devices all pose technical challenges to successful reconstruction. Attention to detail is important in order to minimise complications. In the majority of cases, good outcomes have been reported for the various salvage strategies.

  17. Dynamic Behavior of Variable Stroke Swash Plate Mechanism

    NASA Astrophysics Data System (ADS)

    Yoshida, Katsutoshi; Kasahara, Kohju; Watanabe, Shinichi

    Dynamic behavior of a variable stroke swash plate mechanism is analytically and numerically investigated. Deriving a simple degree of freedom model, we propose a dimensionless arm length to characterize dynamic stabilities of the swash plate angle. We then make a comparison between two types of constraints of the swash plate: one fixating the plate with the swing component and the other linking it with the followers in a frictionless manner. It is numerically shown that the fixed-type constraint improves the stabilities of the mechanism while the frictionless-type constraint makes the mechanism destabilized. An equivalent design technique is also proposed to convert optimal specifications between the different types of the constraints.

  18. Methanotrophy Induces Nitrogen Fixation in Boreal Mosses

    NASA Astrophysics Data System (ADS)

    Tiirola, M. A.

    2014-12-01

    Many methanotrophic bacterial groups fix nitrogen in laboratory conditions. Furthermore, nitrogen (N) is a limiting nutrient in many environments where methane concentrations are highest. Despite these facts, methane-induced N fixation has previously been overlooked, possibly due to methodological problems. To study the possible link between methanotrophy and diazotrophy in terrestrial and aquatic habitats, we measured the co-occurrence of these two processes in boreal forest, peatland and stream mosses using a stable isotope labeling approach (15 N2 and 13 CH4 double labeling) and sequencing of the nifH gene marker. N fixation associated with forest mosses was dependent on the annual N deposition, whereas methane stimulate N fixation neither in high (>3 kg N ha -1 yr -1) nor low deposition areas, which was in accordance with the nifH gene sequencing showing that forest mosses (Pleurozium schreberi and Hylocomium splendens ) carried mainly cyanobacterial N fixers. On the other extreme, in stream mosses (Fontinalis sp.) methane was actively oxidized throughout the year, whereas N fixation showed seasonal fluctuation. The co-occurrence of the two processes in single cell level was proven by co-localizing both N and methane-carbon fixation with the secondary ion mass spectrometry (SIMS) approach. Methanotrophy and diazotrophy was also studied in peatlands of different primary successional stages in the land-uplift coast of Bothnian Bay, in the Siikajoki chronosequence, where N accumulation rates in peat profiles indicate significant N fixation. Based on experimental evidence it was counted that methane-induced N fixation explained over one-third of the new N input in the younger peatland successional stages, where the highest N fixation rates and highest methane oxidation activities co-occurred in the water-submerged Sphagnum moss vegetation. The linkage between methanotrophic carbon cycling and N fixation may therefore constitute an important mechanism in the rapid

  19. Cost effectiveness of treatment with percutaneous Kirschner wires versus volar locking plate for adult patients with a dorsally displaced fracture of the distal radius: analysis from the DRAFFT trial.

    PubMed

    Tubeuf, S; Yu, G; Achten, J; Parsons, N R; Rangan, A; Lamb, S E; Costa, M L

    2015-08-01

    We present an economic evaluation using data from the Distal Radius Acute Fracture Fixation Trial (DRAFFT) to compare the relative cost effectiveness of percutaneous Kirschner wire (K-wire) fixation and volar locking-plate fixation for patients with dorsally-displaced fractures of the distal radius. The cost effectiveness analysis (cost per quality-adjusted life year; QALY) was derived from a multi-centre, two-arm, parallel group, assessor-blind, randomised controlled trial which took place in 18 trauma centres in the United Kingdom. Data from 460 patients were available for analysis, which includes both a National Health Service cost perspective including costs of surgery, implants and healthcare resource use over a 12-month period after surgery, and a societal perspective, which includes the cost of time off work and the need for additional private care. There was only a small difference in QALYs gained for patients treated with locking-plate fixation over those treated with K-wires. At a mean additional cost of £714 (95% confidence interval 588 to 865) per patient, locking-plate fixation presented an incremental cost effectiveness ratio (ICER) of £89,322 per QALY within the first 12 months of treatment. Sensitivity analyses were undertaken to assess the ICER of locking-plate fixation compared with K-wires. These were greater than £30,000. Compared with locking-plate fixation, K-wire fixation is a 'cost saving' intervention, with similar health benefits.

  20. Iris fixation of posterior chamber intraocular lenses.

    PubMed

    Yazdani-Abyaneh, Alireza; Djalilian, Ali R; Fard, Masoud Aghsaei

    2016-12-01

    We introduce a technique for iris fixation of a posterior chamber intraocular lens (IOL) in which most of the procedure is done outside the eye. This minimizes intraocular manipulation, maximizes corneal endothelial preservation, and avoids the risk for IOL drop into the vitreous cavity intraoperatively. The IOL is fixated to the most peripheral part of the iris, resulting in a rounder pupil. Sutures are placed at exact positions on the haptics, resulting in a well-centered IOL.

  1. Catalytic bipolar interconnection plate for use in a fuel cell

    DOEpatents

    Lessing, Paul A.

    1996-01-01

    A bipolar interconnection plate for use between adjacent fuel cell units in a stacked fuel cell assembly. Each plate is manufactured from an intermetallic composition, examples of which include NiAl or Ni.sub.3 Al which can catalyze steam reforming of hydrocarbons. Distributed within the intermetallic structure of the plate is a ceramic filler composition. The plate includes a first side with gas flow channels therein and a second side with fuel flow channels therein. A protective coating is applied to the first side, with exemplary coatings including strontium-doped or calcium-doped lanthanum chromite. To produce the plate, Ni and Al powders are combined with the filler composition, compressed at a pressure of about 10,000-30,000 psi, and heated to about 600.degree.-1000.degree. C. The coating is then applied to the first side of the completed plate using liquid injection plasma deposition or other deposition techniques.

  2. Catalytic bipolar interconnection plate for use in a fuel cell

    SciTech Connect

    Lessing, P.A.

    1996-03-05

    A bipolar interconnection plate is described for use between adjacent fuel cell units in a stacked fuel cell assembly. Each plate is manufactured from an intermetallic composition, examples of which include NiAl or Ni{sub 3}Al which can catalyze steam reforming of hydrocarbons. Distributed within the intermetallic structure of the plate is a ceramic filler composition. The plate includes a first side with gas flow channels therein and a second side with fuel flow channels therein. A protective coating is applied to the first side, with exemplary coatings including strontium-doped or calcium-doped lanthanum chromite. To produce the plate, Ni and Al powders are combined with the filler composition, compressed at a pressure of about 10,000--30,000 psi, and heated to about 600--1000 C. The coating is then applied to the first side of the completed plate using liquid injection plasma deposition or other deposition techniques. 6 figs.

  3. Methods to shorten the duration of an external fixator in the management of tibial infections

    PubMed Central

    Emara, Khaled M; Ghafar, Khaled Abd Al; Al Kersh, Mohamed Ahmed

    2011-01-01

    Massive segmental bone loss due to chronic osteomyelitis represents a considerable challenge to orthopedic surgeons and is a limb threatening condition. The only option available in such a clinical situation is segment transport using the Ilizarov technique of distraction osteogenesis; yet the most common problem in cases of bone transport with the Ilizarov technique in massive bone loss, is the long duration of the fixator. In addition to autologous bone grafting, several mechanical, biologic, and external physical treatment modalities may be employed to promote bone formation and maturation during segment transport in osteomyelitis patients. Mechanical approaches include compressive loading of the distraction regenerate, increased frequency of small increments of distraction, and compression-distraction. Intramedullary nailing and hemicorticotomy can reduce the time in external fixation; however, these techniques are associated with technical difficulties and complications. Exogenous application of low-intensity pulsed ultrasound or pulsed electromagnetic fields may shorten the duration of external fixation. Other promising modalities include diphosphonates, physician-directed use (off-label use) of bone morphogenetic proteins, and local injection of bone marrow aspirate and platelet gel at the osteotomy site. Well-designed clinical studies are needed to establish safe and effective guidelines for various modalities to enhance new bone formation during distraction osteogenesis after segment transfer. PMID:22474640

  4. Variable Nitrogen Fixation in Wild Populus

    PubMed Central

    Doty, Sharon L.; Sher, Andrew W.; Fleck, Neil D.; Khorasani, Mahsa; Bumgarner, Roger E.; Khan, Zareen; Ko, Andrew W. K.; Kim, Soo-Hyung; DeLuca, Thomas H.

    2016-01-01

    The microbiome of plants is diverse, and like that of animals, is important for overall health and nutrient acquisition. In legumes and actinorhizal plants, a portion of essential nitrogen (N) is obtained through symbiosis with nodule-inhabiting, N2-fixing microorganisms. However, a variety of non-nodulating plant species can also thrive in natural, low-N settings. Some of these species may rely on endophytes, microorganisms that live within plants, to fix N2 gas into usable forms. Here we report the first direct evidence of N2 fixation in the early successional wild tree, Populus trichocarpa, a non-leguminous tree, from its native riparian habitat. In order to measure N2 fixation, surface-sterilized cuttings of wild poplar were assayed using both 15N2 incorporation and the commonly used acetylene reduction assay. The 15N label was incorporated at high levels in a subset of cuttings, suggesting a high level of N-fixation. Similarly, acetylene was reduced to ethylene in some samples. The microbiota of the cuttings was highly variable, both in numbers of cultured bacteria and in genetic diversity. Our results indicated that associative N2-fixation occurred within wild poplar and that a non-uniformity in the distribution of endophytic bacteria may explain the variability in N-fixation activity. These results point to the need for molecular studies to decipher the required microbial consortia and conditions for effective endophytic N2-fixation in trees. PMID:27196608

  5. Peak compression factor of proteins.

    PubMed

    Gritti, Fabrice; Guiochon, Georges

    2009-08-14

    An experimental protocol is proposed in order to measure with accuracy and precision the band compression factor G(12)(2) of a protein in gradient RPLC. Extra-column contributions to bandwidth and the dependency of both the retention factor and the reduced height equivalent to a theoretical plate (HETP) on the mobile phase composition were taken into account. The band compression factor of a small protein (insulin, MW kDa) was measured on a 2.1mm x 50mm column packed with 1.7 microm C(4)-bonded bridged ethylsiloxane BEH-silica particles, for 1 microL samples of dilute insulin solution (<0.05g/L). A linear gradient profile of acetonitrile (25-28% acetonitrile in water containing 0.1% trifluoroacetic acid) was applied during three different gradient times (5, 12.5, and 20 min). The mobile phase flow rate was set at 0.20 mL/min in order to avoid heat friction effects (maximum column inlet pressure 180 bar). The band compression factor of insulin is defined as the ratio of the experimental space band variance measured under gradient conditions to the reference space band variance, which would be observed if no thermodynamic compression would take place during gradient elution. It was 0.56, 0.71, and 0.76 with gradient times of 5, 12.5, and 20 min, respectively. These factors are 20-30% smaller than the theoretical band compression factors (0.79, 0.89, and 0.93) calculated from an equation derived from the well-known Poppe equation, later extended to any retention models and columns whose HETP depends on the mobile phase composition. This difference is explained in part by the omission in the model of the effect of the pressure gradient on the local retention factor of insulin during gradient elution. A much better agreement is obtained for insulin when this effect is taken into account. For lower molecular weight compounds, the pressure gradient has little effect but the finite retention of acetonitrile causes a distortion of the gradient shape during the migration of

  6. Earth's Decelerating Tectonic Plates

    SciTech Connect

    Forte, A M; Moucha, R; Rowley, D B; Quere, S; Mitrovica, J X; Simmons, N A; Grand, S P

    2008-08-22

    Space geodetic and oceanic magnetic anomaly constraints on tectonic plate motions are employed to determine a new global map of present-day rates of change of plate velocities. This map shows that Earth's largest plate, the Pacific, is presently decelerating along with several other plates in the Pacific and Indo-Atlantic hemispheres. These plate decelerations contribute to an overall, globally averaged slowdown in tectonic plate speeds. The map of plate decelerations provides new and unique constraints on the dynamics of time-dependent convection in Earth's mantle. We employ a recently developed convection model constrained by seismic, geodynamic and mineral physics data to show that time-dependent changes in mantle buoyancy forces can explain the deceleration of the major plates in the Pacific and Indo-Atlantic hemispheres.

  7. Biomechanical evaluation of an integrated fixation cage during fatigue loading: a human cadaver study.

    PubMed

    Palepu, Vivek; Peck, Jonathan H; Simon, David D; Helgeson, Melvin D; Nagaraja, Srinidhi

    2017-04-01

    OBJECTIVE Lumbar cages with integrated fixation screws offer a low-profile alternative to a standard cage with anterior supplemental fixation. However, the mechanical stability of integrated fixation cages (IFCs) compared with a cage with anterior plate fixation under fatigue loading has not been investigated. The purpose of this study was to compare the biomechanical stability of a screw-based IFC with a standard cage coupled with that of an anterior plate under fatigue loading. METHODS Eighteen functional spinal units were implanted with either a 4-screw IFC or an anterior plate and cage (AP+C) without integrated fixation. Flexibility testing was conducted in flexion-extension (FE), lateral bending (LB), and axial rotation (AR) on intact spines, immediately after device implantation, and post-fatigue up to 20,000 cycles of FE loading. Stability parameters such as range of motion (ROM) and lax zone (LZ) for each loading mode were compared between the 2 constructs at multiple stages of testing. In addition, construct loosening was quantified by subtracting post-instrumentation ROM from post-fatigue ROM. RESULTS IFC and AP+C configurations exhibited similar stability (ROM and LZ) at every stage of testing in FE (p ≥ 0.33) and LB (p ≥ 0.23) motions. In AR, however, IFCs had decreased ROM compared with AP+C constructs at pre-fatigue (p = 0.07) and at all post-fatigue time points (p ≤ 0.05). LZ followed a trend similar to that of ROM in AR. ROM increased toward intact motion during fatigue cycling for AP+C and IFC implants. IFC specimens remained significantly (p < 0.01) more rigid than specimens in the intact condition during fatigue for each loading mode, whereas AP+C construct motion did not differ significantly (p ≥ 0.37) in FE and LB and was significantly greater (p < 0.01) in AR motion compared with intact specimens after fatigue. Weak to moderate correlations (R(2) ≤ 56%) were observed between T-scores and construct loosening, with lower T

  8. A broadband zone plate lens from transformation optics.

    PubMed

    Yang, Rui; Tang, Wenxuan; Hao, Yang

    2011-06-20

    A zone plate lens utilizing a refractive instead of diffractive approach is presented for broadband operation. By utilizing transformation optics, we compress the conventional hyperbolic lens into a flat one with a few zone plates made of all-dielectric materials. Such a transformed lens maintains the broadband performance of the original lens, thus providing a superior alternative to the diffractive Fresnel element which is inherently narrow band.

  9. Cost of external fixation vs external fixation then nailing in bone infection

    PubMed Central

    Emara, Khaled Mohamed; Diab, Ramy Ahmed; Ghafar, Khaled Abd EL

    2015-01-01

    AIM: To study the cost benefit of external fixation vs external fixation then nailing in treatment of bone infection by segment transfer. METHODS: Out of 71 patients with infected nonunion tibia treated between 2003 and 2006, 50 patients fitted the inclusion criteria (26 patients were treated by external fixation only, and 24 patients were treated by external fixation early removal after segment transfer and replacement by internal fixation). Cost of inpatient treatment, total cost of inpatient and outpatient treatment till full healing, and the weeks of absence from school or work were calculated and compared between both groups. RESULTS: The cost of hospital stay and surgery in the group of external fixation only was 22.6 ± 3.3 while the cost of hospital stay and surgery in the group of early external fixation removal and replacement by intramedullary nail was 26.0 ± 3.2. The difference was statistically significant regarding the cost of hospital stay and surgery in favor of the group of external fixation only. The total cost of medical care (surgery, hospital stay, treatment outside the hospital including medications, dressing, physical therapy, outpatient laboratory work, etc.) in group of external fixation only was 63.3 ± 15.1, and total absence from work was 38.6 ± 6.6 wk. While the group of early removal of external fixation and replacement by IM nail, total cost of medical care was 38.3 ± 6.4 and total absence from work or school was 22.7 ± 4.1. The difference was statistically significant regarding the total cost and absence from work in favor of the group of early removal and replacement by IM nail. CONCLUSION: Early removal of external fixation and replacement by intramedullary nail in treatment of infected nonunion showed more cost effectiveness. Orthopaedic society needs to show the cost effectiveness of different procedures to the community, insurance, and health authorities. PMID:25621219

  10. Characteristics of Fixational Eye Movements in Amblyopia: Limitations on Fixation Stability and Acuity?

    PubMed Central

    Kumar, Girish; Li, Roger W.; Levi, Dennis M.

    2015-01-01

    Persons with amblyopia, especially those with strabismus, are known to exhibit abnormal fixational eye movements. In this paper, we compared six characteristics of fixational eye movements among normal control eyes (n=16), the non-amblyopic fellow eyes and the amblyopic eyes of anisometropic (n=14) and strabismic amblyopes (n=14). These characteristics include the frequency, magnitude of landing errors, amplitude and speed of microsaccades, and the amplitude and speed of slow drifts. Fixational eye movements were recorded using retinal imaging while observers monocularly fixated a 1° cross. Eye position data were recovered using a cross-correlation procedure. We found that in general, the characteristics of fixational eye movements are not significantly different between the fellow eyes of amblyopes and controls, and that the strabismic amblyopic eyes are always different from the other groups. Next, we determined the primary factors that limit fixation stability and visual acuity in amblyopic eyes by examining the relative importance of the different oculomotor characteristics, adding acuity (for fixation stability) or fixation stability (for acuity), and the type of amblyopia, as predictive factors in a multiple linear regression model. We show for the first time that the error magnitude of microsaccades, acuity, amplitude and frequency of microsaccades are primary factors limiting fixation stability; while the error magnitude, fixation stability, amplitude of drifts and amplitude of microsaccades are the primary factors limiting acuity. A mediation analysis showed that the effects of error magnitude and amplitude of microsaccades on acuity could be explained, at least in part, by their effects on fixation stability. PMID:25668775

  11. Accelerated plate tectonics.

    PubMed

    Anderson, D L

    1975-03-21

    The concept of a stressed elastic lithospheric plate riding on a viscous asthenosphere is used to calculate the recurrence interval of great earthquakes at convergent plate boundaries, the separation of decoupling and lithospheric earthquakes, and the migration pattern of large earthquakes along an arc. It is proposed that plate motions accelerate after great decoupling earthquakes and that most of the observed plate motions occur during short periods of time, separated by periods of relative quiescence.

  12. Parallel image compression

    NASA Technical Reports Server (NTRS)

    Reif, John H.

    1987-01-01

    A parallel compression algorithm for the 16,384 processor MPP machine was developed. The serial version of the algorithm can be viewed as a combination of on-line dynamic lossless test compression techniques (which employ simple learning strategies) and vector quantization. These concepts are described. How these concepts are combined to form a new strategy for performing dynamic on-line lossy compression is discussed. Finally, the implementation of this algorithm in a massively parallel fashion on the MPP is discussed.

  13. Shock compression profiles in ceramics

    SciTech Connect

    Grady, D.E.; Moody, R.L.

    1996-03-01

    An investigation of the shock compression properties of high-strength ceramics has been performed using controlled planar impact techniques. In a typical experimental configuration, a ceramic target disc is held stationary, and it is struck by plates of either a similar ceramic or by plates of a well-characterized metal. All tests were performed using either a single-stage propellant gun or a two-stage light-gas gun. Particle velocity histories were measured with laser velocity interferometry (VISAR) at the interface between the back of the target ceramic and a calibrated VISAR window material. Peak impact stresses achieved in these experiments range from about 3 to 70 GPa. Ceramics tested under shock impact loading include: Al{sub 2}O{sub 3}, AlN, B{sub 4}C, SiC, Si{sub 3}N{sub 4}, TiB{sub 2}, WC and ZrO{sub 2}. This report compiles the VISAR wave profiles and experimental impact parameters within a database-useful for response model development, computational model validation studies, and independent assessment of the physics of dynamic deformation on high-strength, brittle solids.

  14. Obliquity along plate boundaries

    NASA Astrophysics Data System (ADS)

    Philippon, Mélody; Corti, Giacomo

    2016-12-01

    Most of the plate boundaries are activated obliquely with respect to the direction of far field stresses, as roughly only 8% of the plate boundaries total length shows a very low obliquity (ranging from 0 to 10°, sub-orthogonal to the plate displacement). The obliquity along plate boundaries is controlled by (i) lateral rheological variations within the lithosphere and (ii) consistency with the global plate circuit. Indeed, plate tectonics and magmatism drive rheological changes within the lithosphere and consequently influence strain localization. Geodynamical evolution controls large-scale mantle convection and plate formation, consumption, and re-organization, thus triggering plate kinematics variations, and the adjustment and re-orientation of far field stresses. These geological processes may thus result in plate boundaries that are not perpendicular but oblique to the direction of far field stresses. This paper reviews the global patterns of obliquity along plate boundaries. Using GPlate, we provide a statistical analysis of present-day obliquity along plate boundaries. Within this framework, by comparing natural examples and geological models, we discuss deformation patterns and kinematics recorded along oblique plate boundaries.

  15. Plating Tank Control Software

    SciTech Connect

    Krafcik, John

    1998-03-01

    The Plating Tank Control Software is a graphical user interface that controls and records plating process conditions for plating in high aspect ratio channels that require use of low current and long times. The software is written for a Pentium II PC with an 8 channel data acquisition card, and the necessary shunt resistors for measuring currents in the millampere range.

  16. Rotatable shear plate interferometer

    DOEpatents

    Duffus, Richard C.

    1988-01-01

    A rotatable shear plate interferometer comprises a transparent shear plate mounted obliquely in a tubular supporting member at 45.degree. with respect to its horizontal center axis. This tubular supporting member is supported rotatably around its center axis and a collimated laser beam is made incident on the shear plate along this center axis such that defocus in different directions can be easily measured.

  17. HYDRODYNAMIC COMPRESSIVE FORGING.

    DTIC Science & Technology

    HYDRODYNAMICS), (*FORGING, COMPRESSIVE PROPERTIES, LUBRICANTS, PERFORMANCE(ENGINEERING), DIES, TENSILE PROPERTIES, MOLYBDENUM ALLOYS , STRAIN...MECHANICS), BERYLLIUM ALLOYS , NICKEL ALLOYS , CASTING ALLOYS , PRESSURE, FAILURE(MECHANICS).

  18. Modified biplanar open-wedge high tibial osteotomy with rigid locking plate to treat varus knee*

    PubMed Central

    Zhang, Hai-ning; Zhang, Jie; Lv, Cheng-yu; Leng, Ping; Wang, Ying-zhen; Wang, Xiang-da; Wang, Chang-yao

    2009-01-01

    Objective: To introduce and characterize the modified biplanar opening high tibial osteotomy with rigid fixation to treat varus knee in young and active patients. Methods: Between June 2001 to July 2008, 18 patients with monocompartmental degeneration of the knee combined with a varus malalignment of the leg had the modified biplanar opening high tibial osteotomy and the osteotomy was fixed with the locking plates (Locking Compression Plate System). The mean varus deformity before operation was 11.5° (5°~19°) and no degenerative changes were found in other departments. Stability of the knee was normal in 15 patients, but ruptures in anterior cruciate ligaments or lateral collateral ligament were presented in the remaining 3 patients. Preoperative symptom was mainly limited in the pain of medial compartment. The preoperative and follow-up data for the range of motion and Lysholm score were determined. Subjective satisfactory examination was also applied to the patients for the operation they selected. Results: All of the patients were followed up with an average of 32.5 months (12~82 months). There was no ununion or delayed union in this group during the follow-up period. No complications like broken plate, nerve injury, or blood vessel injury occurred. The postoperative average corrected degree was 9.5° (5.5°~18°). No degenerations developed in the three departments of the knee. The Lysholm scores before and after surgery were 42.5 and 77.5, respectively (P<0.01). The overall fineness rate was 83.3%. The subjective satisfactory survey demonstrated that about 83.3% patients showed satisfactory on the operation. There was no obvious difference in the range of motion before and after operation, but significant changes were found in the Lysholm score and varus degree from preoperative to follow-up. Conclusion: Proximal opening high tibial osteotomy performed in conjunction with the special rigid locking plate yielded good results for symptomatic genu varum. This

  19. Anterior approach for operative fixation of coronoid fractures in complex elbow instability.

    PubMed

    Reichel, Lee M; Milam, Graham S; Reitman, Charles A

    2012-06-01

    The coronoid process has been shown to play a critical role in ulnohumeral stability. Coronoid process fractures can occur in isolation or as part of a complex injury pattern. The most common complex pattern, known as the "terrible triad," includes a radial head fracture and elbow dislocation along with the coronoid fracture. Failure to address these fractures and ligamentous injuries can result in recurrent instability and progression to painful arthrosis. Both medial and lateral approaches to the coronoid have been popularized in recent literature, but there is no universally accepted approach. Common fixation techniques include suture lasso, suture anchors, lag screws, and plating all of which have various drawbacks. We describe a direct anterior approach to address coronoid process fractures made in addition to a lateral approach to address radial head and lateral collateral ligament injuries. Coronoid fractures addressed through the anterior approach were stabilized with anterior to posterior screw fixation combined with buttress plating, which allowed anatomic reduction and stable internal fixation at short-term follow-up.

  20. Are there any complications with bioabsorbable fixation devices? A 10 year review in orthognathic surgery.

    PubMed

    Laine, P; Kontio, R; Lindqvist, C; Suuronen, R

    2004-04-01

    Bioabsorbable fixation devices have been used in our departments between November 1991 and November 2001 in orthognathic surgery. The aim of this retrospective study was to assess all complications experienced during this time period, when we have operated 163 patients who have undergone 329 orthognathic osteotomies fixated with bioresorbable devices. No postoperative intermaxillary fixation was used. Light guiding elastics were used for 5 to 7 weeks. Patients' acceptance was generally excellent and very few complications occurred during this follow-up of 10 years. The complications were minor and did not affect the end results of the operations. Minor complications occurred in 14 patients (8.6%). Only one patient (0.6%) had a postoperative infection with elevated infection parameters. The other minor complications consisted mainly of dehiscence of the wound and plate exposure together with granulation tissue in the operation field. The rest of the complications occurred in the beginning of our study, when large screw heads on top of the bone irritated the patient and had to be removed. Insufficient fixation resulted in open bite in three patients (1.8%) in the beginning of the trial use of new devices, which no longer are used. Based on our experience, bioresorbable devices are safe to be used in orthognathic procedures. However, there is a learning curve, as there is with all new methods introduced.

  1. Superfund record of decision (EPA Region 1): New Hampshire Plating Company, Merrimack, NH, September 28, 1998

    SciTech Connect

    1999-03-01

    This decision document presents the selected remedial action for the New Hampshire Plating Company Superfund Site (Site) located in Merrimack, New Hampshire. This ROD sets forth the selected remedy for the New Hampshire Plating Company Site, which involves in-place treatment of metal-contaminated soil by chemical fixation, natural attenuation of contaminated groundwater in the overburden aquifers, and institutional controls to allow for acceptable re-development and prevent future ingestion of contaminated groundwater.

  2. Biomechanical evaluation of the Pinless external fixator.

    PubMed

    Stene, G M; Frigg, R; Schlegel, U; Swiontkowski, M

    1992-01-01

    In open fractures especially in those with severe soft tissue damage, fracture stabilisation is best achieved by using external fixators. There are some intrinsic complications which occur during classical external pin fixation. To overcome the problem of pin track infection and vascular damage from drilling, the Pinless external fixator was developed. It is based on the idea of a forceps with trocar points, which only penetrate the bone cortex superficially. The function of the device was tested in two mechanical trials and two in vitro tests in which one pinless clamp was put under a controlled load of 50 N, 150 cycles/day and studied over a 5 week period in sheep. The loads and time range of the experiment were chosen to simulate a temporary fracture stabilisation in a patient not bearing weight. The main question to be answered was whether the Pinless external fixator would be able to maintain stable fixation. Furthermore, it was to determine the changes at the trocar-to-bone interface. The clamp was found to maintain 72% of the initially applied clamping force after 5 weeks of in vivo application and it was found to be tight at removal. Some decrease of clamping force was found during the first 20 days and then the force tended to level off. There was no slippage nor did the clamp penetrate the cortex. There were no obvious signs of infection around the trocar-holes and in the bacterial tests no pathological cultures were grown. Histology revealed very localised bone reactions, the indentation caused by the trocar tips being only 1.2 mm deep. The study concludes, as far as could be ascertained from these tests, that it is safe to use pinless external fixation for temporary fracture fixation.

  3. Association between bicortical screw fixation at upper instrumented vertebra and risk for upper instrumented vertebra fracture.

    PubMed

    Park, Young-Seop; Hyun, Seung-Jae; Choi, Ho Yong; Kim, Ki-Jeong; Jahng, Tae-Ahn

    2017-03-03

    OBJECTIVE The aim of this study was to investigate the risk of upper instrumented vertebra (UIV) fractures associated with UIV screw fixation (unicortical vs bicortical) and polymethylmethacrylate (PMMA) augmentation after adult spinal deformity surgery. METHODS A single-center, single-surgeon consecutive series of adult patients who underwent lumbar fusion for ≥ 4 levels (that is, the lower instrumented vertebra at the sacrum or pelvis and the UIV of the thoracolumbar spine [T9-L2]) were retrospectively reviewed. Age, sex, follow-up duration, sagittal UIV angle immediately postoperatively including several balance-related parameters (lumbar lordosis [LL], pelvic incidence, and sagittal vertical axis), bone mineral density, UIV screw fixation type, UIV PMMA augmentation, and UIV fracture were evaluated. Patients were divided into 3 groups: Group U, 15 patients with unicortical screw fixation at the UIV; Group P, 16 with bicortical screw fixation and PMMA augmentation at the UIV; and Group B, 21 with bicortical screw fixation without PMMA augmentation at the UIV. RESULTS The mean number of levels fused was 6.5 ± 2.5, 7.5 ± 2.5, and 6.5 ± 2.5; the median age was 50 ± 29, 72 ± 6, and 59 ± 24 years; and the mean follow-up was 31.5 ± 23.5, 13 ± 6, and 24 ± 17.5 months in Groups U, P, and B, respectively (p > 0.05). There were no significant differences in balance-related parameters (LL, sagittal vertical axis, pelvic incidence-LL, and so on) among the groups. UIV fracture rates in Groups U (0%), P (31.3%), and B (42.9%) increased in sequence by group (p = 0.006). UIV bicortical screw fixation increased the risk for UIV fracture (OR 5.39; p = 0.02). CONCLUSIONS Bicortical screw fixation at the UIV is a major risk factor for early UIV compression fracture, regardless of whether a thoracolumbosacral orthosis is used. To reduce the proximal junctional failure, unicortical screw fixation at the UIV is essential in adult spinal deformity correction surgery.

  4. Texture Studies and Compression Behaviour of Apple Flesh

    NASA Astrophysics Data System (ADS)

    James, Bryony; Fonseca, Celia

    Compressive behavior of fruit flesh has been studied using mechanical tests and microstructural analysis. Apple flesh from two cultivars (Braeburn and Cox's Orange Pippin) was investigated to represent the extremes in a spectrum of fruit flesh types, hard and juicy (Braeburn) and soft and mealy (Cox's). Force-deformation curves produced during compression of unconstrained discs of apple flesh followed trends predicted from the literature for each of the "juicy" and "mealy" types. The curves display the rupture point and, in some cases, a point of inflection that may be related to the point of incipient juice release. During compression these discs of flesh generally failed along the centre line, perpendicular to the direction of loading, through a barrelling mechanism. Cryo-Scanning Electron Microscopy (cryo-SEM) was used to examine the behavior of the parenchyma cells during fracture and compression using a purpose designed sample holder and compression tester. Fracture behavior reinforced the difference in mechanical properties between crisp and mealy fruit flesh. During compression testing prior to cryo-SEM imaging the apple flesh was constrained perpendicular to the direction of loading. Microstructural analysis suggests that, in this arrangement, the material fails along a compression front ahead of the compressing plate. Failure progresses by whole lines of parenchyma cells collapsing, or rupturing, with juice filling intercellular spaces, before the compression force is transferred to the next row of cells.

  5. Anterior pre-tensioned external fixator for pelvic fractures and dislocations. Initial clinical series.

    PubMed

    Queipo-de-Llano, A; Lombardo-Torre, M; Leiva-Gea, A; Delgado-Rufino, F B; Luna-González, F

    2016-12-01

    In the treatment of unstable pelvic ring fractures, external fixators have the limitation of not adequately stabilizing the injured posterior elements. This article presents a novel and simple technique of temporary external fixation of the pelvic ring, able to produce compression of both the anterior and posterior pelvic elements. A curved flexible carbon-fiber rod is used, pre-tensioned before attachment to supra-acetabular Schanz screws. Although more extensive clinical experience is required, favorable preliminary results in a series of 13 patients with unstable pelvic fracture were encouraging: the aim of closing the posterior and anterior elements of the pelvic ring was achieved in all cases treated with this technique, and 12 patients survived. Radiological results were excellent in 3 cases and good in 9 cases. No major complications, such as secondary displacement, vertical re-displacement or deep infection, were observed. Mean operative time was 25min, compatible with emergency management.

  6. The Okhotsk Plate and the Eurasia-North America plate boundary zone.

    NASA Astrophysics Data System (ADS)

    Hindle, David; Mackey, Kevin

    2014-05-01

    The Eurasia-North America plate boundary zone transitions from spreading at rates of ~ 25mm/yr in the North Atlantic, to compression at rates of ~ 5mm/yr in the region of the Okhotsk plate. Because the pole of rotation between Eurasia and North America lies more or less on their mutual boundary, there is a linear change in rate along the boundary, and regions near the euler pole are subject to extremely low deformation rates. The Okhotsk - Eurasia - North America triple junction lies slightly south of the rotation pole, placing the Okhotsk plate entirely in a weakly contractional setting. Regions near the triple junction absorb 1mm/yr contraction. Further south, towards the shoreline of the Okhotsk sea, up to 5 mm/yr contraction may be absorbed within the plate. How shortening is accommodated across the boundary remains an open question. One possibility is wholesale extrusion of the entire Okhotsk plate (or possibly its northwestern corner) along two plate boundary strike slip faults (Eurasia-Okhostk and North America Okhotsk). The problem with this model is that the seismic record does not presently clearly support it, with the largest events distributed both within the plate interior and on its boundaries. This may suggest that instead, the Okhotsk plate, and particularly its north-western end, consists of a series of smaller blocks which shuffle against each other, partially accommodating extrusion, but also permitting some internal deformation and change of shape of the Okhotsk plate itself. We present analyses of the very sparse seismic record from the region, as well as geometric-kinematic, tectonic models of the possible deformation of northwest Okhotsk to try to better understand the different probabilities of how this slowly deforming plate boundary zone is behaving.

  7. Malachite green photosensitive plates.

    PubMed

    Solano, C

    1989-08-15

    An experimental study of the behavior of malachite green sensitized plates was carried out. The transmittance variation of the irradiated plates was taken as a parameter. It has been observed that photoreduction in the malachite green plates is present only when ammonium dichromate is added to the plates. The introduction of external electron donors does not improve the photochemical reaction. It has been determined that malachite green molecules form a weak complex with the dichromate molecules and this complex can only be destroyed photochemically. This effect can explain the limited response of the malachite green dichromated plates.

  8. An improved plating process

    NASA Technical Reports Server (NTRS)

    Askew, John C.

    1994-01-01

    An alternative to the immersion process for the electrodeposition of chromium from aqueous solutions on the inside diameter (ID) of long tubes is described. The Vessel Plating Process eliminates the need for deep processing tanks, large volumes of solutions, and associated safety and environmental concerns. Vessel Plating allows the process to be monitored and controlled by computer thus increasing reliability, flexibility and quality. Elimination of the trivalent chromium accumulation normally associated with ID plating is intrinsic to the Vessel Plating Process. The construction and operation of a prototype Vessel Plating Facility with emphasis on materials of construction, engineered and operational safety and a unique system for rinse water recovery are described.

  9. Posterior Fixation Techniques in the Subaxial Cervical Spine

    PubMed Central

    Ghori, Ahmer; Makanji, Heeren; Cha, Thomas

    2015-01-01

    This article reviews the historical context, indications, techniques, and complications of four posterior fixation techniques to stabilize the subaxial cervical spine. Specifically, posterior wiring, laminar screw fixation, lateral mass fixation, and pedicle screw fixation are among the common methods of operative fixation of the subaxial cervical spine. While wiring and laminar screw fixation are now rarely used, both lateral mass and pedicle screw fixation are technically challenging and present the risk of significant complications if performed incorrectly. With a sound understanding of anatomy and rigorous preoperative evaluation of bony structures, both lateral mass and pedicle screw fixation provide a safe and reliable method for subaxial cervical spine fixation. PMID:26594602

  10. Multicolor printing plate joining

    NASA Technical Reports Server (NTRS)

    Waters, W. J. (Inventor)

    1984-01-01

    An upper plate having ink flow channels and a lower plate having a multicolored pattern are joined. The joining is accomplished without clogging any ink flow paths. A pattern having different colored parts and apertures is formed in a lower plate. Ink flow channels each having respective ink input ports are formed in an upper plate. The ink flow channels are coated with solder mask and the bottom of the upper plate is then coated with solder. The upper and lower plates are pressed together at from 2 to 5 psi and heated to a temperature of from 295 F to 750 F or enough to melt the solder. After the plates have cooled and the pressure is released, the solder mask is removed from the interior passageways by means of a liquid solvent.

  11. Application of alternative fixatives to formalin in diagnostic pathology.

    PubMed

    Benerini Gatta, L; Cadei, M; Balzarini, P; Castriciano, S; Paroni, R; Verzeletti, A; Cortellini, V; De Ferrari, F; Grigolato, P

    2012-05-04

    Fixation is a critical step in the preparation of tissues for histopathology. The objective of this study was to investigate the effects of different fixatives vs formalin on proteins and DNA, and to evaluate alternative fixation for morphological diagnosis and nucleic acid preservation for molecular methods. Forty tissues were fixed for 24 h with six different fixatives: the gold standard fixative formalin, the historical fixatives Bouin and Hollande, and the alternative fixatives Greenfix, UPM and CyMol. Tissues were stained (Haematoxylin-Eosin, Periodic Acid Schiff, Trichromic, Alcian-blue, High Iron Diamine), and their antigenicity was determined by immunohistochemistry (performed with PAN-CK, CD31, Ki-67, S100, CD68, AML antibodies). DNA extraction, KRAS sequencing, FISH for CEP-17, and flow cytometry analysis of nuclear DNA content were applied. For cell morphology the alternative fixatives (Greenfix, UPM, CyMol) were equivalent to formalin. As expected, Hollande proved the best fixative for morphology. The morphology obtained with Bouin was comparable to that with formalin. Hollande was the best fixative for histochemistry. Bouin proved equivalent to formalin. The alternative fixatives were equivalent to formalin, although with greater variability in haematoxylin-eosin staining. It proved possible to obtain immunohistochemical staining largely equivalent to that following formalin-fixation with the following fixatives: Greenfix, Hollande, UPM and CyMol. The tissues fixed in Bouin did not provide results comparable to those obtained with formalin. The DNA extracted from samples fixed with alternative fixatives was found to be suitable for molecular analysis.

  12. High-impact poly(L/D-lactide) for fracture fixation: in vitro degradation and animal pilot study.

    PubMed

    Tams, J; Joziasse, C A; Bos, R R; Rozema, F R; Grijpma, D W; Pennings, A J

    1995-12-01

    The impact strength of amorphous lactide copolymers can be significantly improved by blending with biodegradable rubbers. Rubber toughening of amorphous poly(85L/15D -lactide) with the copolymer poly (50/50-trimethylenecarbonate-co-epsilon-caprolactone) results in a high-impact polymer (PDLLA/P(TMC-CL)). In vitro, the PDLLA/P(TMC-CL) blend retained its tensile and impact strength for a long period of time. Up to 45 weeks, the amount of water absorbed by the blend remained very low and no significant mass loss was observed. To test the suitability for fracture fixation, in a dog study mandibular fractures were fixated with PDLLA/P(TMC-CL) bone plates and screws. Bone healing was uneventful without premature failure of the implants. Although long-term degradation studies have to be carried out, PDLLA/P(TMC-CL) seems to be promising for application in fracture fixation.

  13. Buckling analysis for structural sections and stiffened plates reinforced with laminated composites.

    NASA Technical Reports Server (NTRS)

    Viswanathan, A. V.; Soong, T.-C.; Miller, R. E., Jr.

    1972-01-01

    A classical buckling analysis is developed for stiffened, flat plates composed of a series of linked flat plate and beam elements. Plates are idealized as multilayered orthotropic elements; structural beads and lips are idealized as beams. The loaded edges of the stiffened plate are simply supported and the conditions at the unloaded edges can be prescribed arbitrarily. The plate and beam elements are matched along their common junctions for displacement continuity and force equilibrium in an exact manner. Offsets between elements are considered in the analysis. Buckling under uniaxial compressive load for plates, sections and stiffened plates is investigated. Buckling loads are found as the lowest of all possible general and local failure modes and the mode shape is used to determine whether buckling is a local or general instability. Numerical correlations with existing analysis and test data for plates, sections and stiffened plates including boron-reinforced structures are discussed. In general, correlations are reasonably good.

  14. The fixation and saccade P3.

    PubMed

    Dandekar, Sangita; Ding, Jian; Privitera, Claudio; Carney, Thom; Klein, Stanley A

    2012-01-01

    Although most instances of object recognition during natural viewing occur in the presence of saccades, the neural correlates of objection recognition have almost exclusively been examined during fixation. Recent studies have indicated that there are post-saccadic modulations of neural activity immediately following eye movement landing; however, whether post-saccadic modulations affect relatively late occurring cognitive components such as the P3 has not been explored. The P3 as conventionally measured at fixation is commonly used in brain computer interfaces, hence characterizing the post-saccadic P3 could aid in the development of improved brain computer interfaces that allow for eye movements. In this study, the P3 observed after saccadic landing was compared to the P3 measured at fixation. No significant differences in P3 start time, temporal persistence, or amplitude were found between fixation and saccade trials. Importantly, sensory neural responses canceled in the target minus distracter comparisons used to identify the P3. Our results indicate that relatively late occurring cognitive neural components such as the P3 are likely less sensitive to post saccadic modulations than sensory neural components and other neural activity occurring shortly after eye movement landing. Furthermore, due to the similarity of the fixation and saccade P3, we conclude that the P3 following saccadic landing could possibly be used as a viable signal in brain computer interfaces allowing for eye movements.

  15. Quantitative vertebral compression fracture evaluation using a height compass

    NASA Astrophysics Data System (ADS)

    Yao, Jianhua; Burns, Joseph E.; Wiese, Tatjana; Summers, Ronald M.

    2012-03-01

    Vertebral compression fractures can be caused by even minor trauma in patients with pathological conditions such as osteoporosis, varying greatly in vertebral body location and compression geometry. The location and morphology of the compression injury can guide decision making for treatment modality (vertebroplasty versus surgical fixation), and can be important for pre-surgical planning. We propose a height compass to evaluate the axial plane spatial distribution of compression injury (anterior, posterior, lateral, and central), and distinguish it from physiologic height variations of normal vertebrae. The method includes four steps: spine segmentation and partition, endplate detection, height compass computation and compression fracture evaluation. A height compass is computed for each vertebra, where the vertebral body is partitioned in the axial plane into 17 cells oriented about concentric rings. In the compass structure, a crown-like geometry is produced by three concentric rings which are divided into 8 equal length arcs by rays which are subtended by 8 common central angles. The radius of each ring increases multiplicatively, with resultant structure of a central node and two concentric surrounding bands of cells, each divided into octants. The height value for each octant is calculated and plotted against octants in neighboring vertebrae. The height compass shows intuitive display of the height distribution and can be used to easily identify the fracture regions. Our technique was evaluated on 8 thoraco-abdominal CT scans of patients with reported compression fractures and showed statistically significant differences in height value at the sites of the fractures.

  16. Accounting For Compressibility In Viscous Flow In Pipes

    NASA Technical Reports Server (NTRS)

    Steinle, Frank W.; Gee, Ken; Murthy, Sreedhara V.

    1991-01-01

    Method developed to account for effects of compressibility in viscous flows through long, circular pipes of uniform diameter. Based on approximation of variations in density and velocity across pipe cross section by profile equations developed for boundary-layer flow between flat plates.

  17. 26. Central compression lock, north span facing north. Compression lock ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    26. Central compression lock, north span facing north. Compression lock locks two spans together at highest point. There are three compression locks. - Henry Ford Bridge, Spanning Cerritos Channel, Los Angeles-Long Beach Harbor, Los Angeles, Los Angeles County, CA

  18. Fractal image compression

    NASA Technical Reports Server (NTRS)

    Barnsley, Michael F.; Sloan, Alan D.

    1989-01-01

    Fractals are geometric or data structures which do not simplify under magnification. Fractal Image Compression is a technique which associates a fractal to an image. On the one hand, the fractal can be described in terms of a few succinct rules, while on the other, the fractal contains much or all of the image information. Since the rules are described with less bits of data than the image, compression results. Data compression with fractals is an approach to reach high compression ratios for large data streams related to images. The high compression ratios are attained at a cost of large amounts of computation. Both lossless and lossy modes are supported by the technique. The technique is stable in that small errors in codes lead to small errors in image data. Applications to the NASA mission are discussed.

  19. Yield Surfaces for Anisotropic Plates

    NASA Astrophysics Data System (ADS)

    Walker, J. D.; Thacker, B. H.

    1999-06-01

    Modern aerospace systems are incorporating composite materials into their structures. Often, the composite materials are anisotropic in their mechanical response due to the geometric layout of fibers. For many years, the failure surfaces of anisotropic materials were thought to be characterizable by a quadratic function in the stress, often referred to as a Tsai-Wu yield surface, or, in a more restrictive form, a Tsai-Hill yield surface. Such a representation does not work for materials that are strong in two directions and weak in one direction, which, unfortunately, is the case of most interest since it represents most composite plates. This paper demonstrates the impossibility of modeling the failure surface with both the Tsai-Wu and Tsai-Hill failure surfaces. We then present a yield surface based on the lemniscate, which is quartic in the stress. This new yield surface addresses the case of strong in two directions and weak in one. Calculations with a fragment impacting a composite plate modeled with the new yield surface are presented. Modifications of the yield surface are presented to allow, in a limited way, materials that are both anisotropic and have differing strengths in tension and compression.

  20. The effects of embedded internal delaminations on composite laminate compression strength; an experimental review

    NASA Technical Reports Server (NTRS)

    Nettles, Alan T.

    1994-01-01

    Delaminations in laminated composite materials can degrade the compressive strength of these materials. Delaminations can form as a result of impact damage or processing flaws. In order to better understand the effects of these delaminations on the compressive behavior of laminated composite plates, programs have been conducted to assess the criticality of prescribed delaminations of known size, shape, and location on the compression strength of laminated composites. A review of these programs is presented along with highlights of pertinent findings from each.

  1. Mechanical analysis of a rodent segmental bone defect model: the effects of internal fixation and implant stiffness on load transfer.

    PubMed

    Yavari, S Amin; van der Stok, J; Ahmadi, S M; Wauthle, R; Schrooten, J; Weinans, H; Zadpoor, A A

    2014-08-22

    Segmental bone defect animal models are often used for evaluating the bone regeneration performance of bone substituting biomaterials. Since bone regeneration is dependent on mechanical loading, it is important to determine mechanical load transfer after stabilization of the defect and to study the effects of biomaterial stiffness on the transmitted load. In this study, we assess the mechanical load transmitted over a 6mm femur defect that is stabilized with an internal PEEK fixation plate. Subsequently, three types of selective laser melted porous titanium implants with different stiffness values were used to graft the defect (five specimens per group). In one additional group, the defect was left empty. Micro strain gauges were used to measure strain values at four different locations of the fixation plate during external loading on the femoral head. The load sharing between the fixation plate and titanium implant was highly variable with standard deviations of measured strain values between 31 and 93% of the mean values. As a consequence, no significant differences were measured between the forces transmitted through the titanium implants with different elastic moduli. Only some non-significant trends were observed in the mean strain values that, consistent with the results of a previous finite element study, implied the force transmitted through the implant increases with the implant stiffness. The applied internal fixation method does not standardize mechanical loading over the defect to enable detecting small differences in bone regeneration performances of bone substituting biomaterials. In conclusion, the fixation method requires further optimization to reduce the effects of the operative procedure and make the mechanical loading more consistent and improve the overall sensitivity of this rat femur defect model.

  2. Control and Functions of Fixational Eye Movements

    PubMed Central

    Rucci, Michele; Poletti, Martina

    2016-01-01

    Humans and other species explore a visual scene by rapidly shifting their gaze 2-3 times every second. Although the eyes may appear immobile in the brief intervals in between saccades, microscopic (fixational) eye movements are always present, even when attending to a single point. These movements occur during the very periods in which visual information is acquired and processed and their functions have long been debated. Recent technical advances in controlling retinal stimulation during normal oculomotor activity have shed new light on the visual contributions of fixational eye movements and their degree of control. The emerging body of evidence, reviewed in this article, indicates that fixational eye movements are important components of the strategy by which the visual system processes fine spatial details, enabling both precise positioning of the stimulus on the retina and encoding of spatial information into the joint space-time domain. PMID:27795997

  3. Biometric recognition via fixation density maps

    NASA Astrophysics Data System (ADS)

    Rigas, Ioannis; Komogortsev, Oleg V.

    2014-05-01

    This work introduces and evaluates a novel eye movement-driven biometric approach that employs eye fixation density maps for person identification. The proposed feature offers a dynamic representation of the biometric identity, storing rich information regarding the behavioral and physical eye movement characteristics of the individuals. The innate ability of fixation density maps to capture the spatial layout of the eye movements in conjunction with their probabilistic nature makes them a particularly suitable option as an eye movement biometrical trait in cases when free-viewing stimuli is presented. In order to demonstrate the effectiveness of the proposed approach, the method is evaluated on three different datasets containing a wide gamut of stimuli types, such as static images, video and text segments. The obtained results indicate a minimum EER (Equal Error Rate) of 18.3 %, revealing the perspectives on the utilization of fixation density maps as an enhancing biometrical cue during identification scenarios in dynamic visual environments.

  4. Fixation of tendo Achilles avulsion fracture.

    PubMed

    Lui, T H

    2009-01-01

    Achilles tendon ruptures occur commonly in the midsubstance of the tendon, usually 2-6 cm proximal to the insertion to the calcaneus. Ruptures near its insertion into the calcaneus are less common and mostly found in hyperpronators with a heel spur (Haglund's deformity). Avulsion of the bony insertion of the Achilles tendon at the calcaneus is infrequent and is diagnosed by radiography. Open reduction and internal fixation is indicated to achieve bone to bone healing and restoration of the function and continuity of the triceps surae mechanism. Screw fixation is not effective to resist the pull out tension of the triceps surae. Moreover, the prominent screw head may cause skin impingement. More secure fixation method is necessary in order to allow early functional rehabilitation. We describe a technique to fix the avulsed fragment of Achilles tendon insertion with 2 suture anchors. This can neutralize the pull of the triceps surae and early post-operative rehabilitation programme is allowed.

  5. Tectonic development of the Maya plate

    SciTech Connect

    Charleston, S.; Concit, S.C.; Sanchez, R.

    1985-01-01

    The Maya Plate is located at the southern margin of the North American Plate, it comprises from north to south, the following tectonic provinces: The Yucatan Platform, (including the lowlands of Peten and the oil-rich offshore platform of the Campeche Bank), the Macuspana basin, the Salt Basin, the NW-SE trending Sierra de Chiapas Folded Belt, the Chiapas depression and the Ciapas Massif. During the past, the deformation of the Maya Plate, have been attributed to the Laramide Orogeny. The present study develops a model based on the interaction between the Maya, Caribbean and the oceanic Cocos-plates, assuming that during the Middle Miocene, the development of the left-lateral Motagua Fault between the Maya and Caribbean plates, displaced the Yucatan Platform in a southwestward direction. It is consider that the combine action of two opposite forces, was responsible for the development of most of the Sierra de Chiapas major anticlines and synclines. Finally the model suggests that these structures, were later affected by trans-compressive forces, originated as a secondary response, due to the development of several left-lateral transcurrent faults, associated with the Polochic Fault System.

  6. Arthrodesis with external fixation in the unstable or misaligned Charcot ankle in patients with diabetes mellitus.

    PubMed

    Fabrin, Jesper; Larsen, Kirsten; Holstein, Per E

    2007-06-01

    The unstable or misaligned Charcot ankle with or without chronic foot ulceration is a major clinical challenge. When it cannot be accommodated with an ankle foot orthosis, surgical treatment is indicated in order to avoid leg amputation. This requires extensive soft tissue release and bony resection to realign the foot and arthrodesis with internal or external fixation. The guidance in the literature favors internal fixation. This article reports results with external fixation in 11 patients (12 feet) over a period of 12 years. External fixation was chosen as the surgical option because of the presence of foot ulcers with the attendent risk of infection. There were 7 tibio-talar and 5 tibio-calcaneal fusions. Compression was applied for 6 weeks with an external frame according to Charnley, followed by 6 weeks with total-contact cast. Weight bearing with a rigid leather brace was allowed after 12 weeks. In one case, transtibial amputation was required due to loosening of the distal pins from osteopenic disintegrating bone. In 11 cases (92%), the foot was successfully realigned and independent walking with a brace retained during the follow-up of median 48 months (10-102 months). Bony union took place in 5 out of 7 cases with tibio-talar fusion and in 1 out of 5 with tibio-calcaneal fusion. The functional result in cases with fibrous union was, however, satisfactory. Although meaningful comparisons of series are difficult to conduct and interpret from, the limb salvage rate was similar to results with internal fixation. The authors consider the results to be encouraging and to be used to develop a higher level of evidence.

  7. Metallic Fixation of Mandibular Segmental Defects: Graft Immobilization and Orofacial Functional Maintenance

    PubMed Central

    Shayesteh Moghaddam, Narges; Jahadakbar, Ahmadreza; Amerinatanzi, Amirhesam; Elahinia, Mohammad; Miller, Michael

    2016-01-01

    Background: The aim of this study is to investigate the behavior of the healthy mandible under maximum molar bite force to demonstrate the problems associated with the current standard of care procedures for mandibular segmental defect reconstruction (ie, use of Ti–6Al–4V hardware and either a single- or double-barrel fibular graft). With current Ti–6Al–4V mandibular reconstruction hardware, there is a significant stiffness mismatch among the hardware, graft, and the remaining host anatomy. How the distribution of mechanical forces through the mandible is altered after a segmental bone loss and reconstruction is incompletely understood. Methods: We studied a healthy adult mandible for stress, strain, and reaction force distribution during normal mastication. Stress distribution of this model was then used to study problems encountered after mandibular segmental defect reconstructive surgery. We model the use of both single- and double-barrel fibular grafts to repair the loss of the left M1–3 containing segment of the mandible. These simulations were done using 2 sets of plates with different thicknesses. Results: We found that the stiffness mismatching between the fixation hardware and the graft and host bone causes stress shielding of that bone and stress concentrations in the fixation hardware and screws. These effects are expected, especially during the bone healing period. However, long term, this abnormal stress–strain distribution may lead to either the hardware’s failure due to stress concentration or graft failure due to bone resorption as a result of stress shielding. We found that the stress–strain distribution is more normal with a double-barrel fibular graft. Additionally, we found that thinner fixation plates can reduce stress shielding. Conclusion: The proposed model can be used to evaluate the performance and optimization of the fixation device. PMID:27757323

  8. Surgical site infection complicating internal fixation of fractures: incidence and risk factors.

    PubMed Central

    Thanni, Lateef O. A.; Aigoro, Nofiu O.

    2004-01-01

    BACKGROUND: There is a dearth of data on surgical site infections (SSIs) complicating internal fixation of fractures from Nigeria. AIMS: To determine the incidence and risk factors for SSIs following internal fixation of fracture. METHODS: A cohort of 90 patients with long bone fractures that were stabilized internally with metallic devices was studied prospectively and retrospectively. RESULTS: The incidence of SSI was 12%. The isolated organisms were Staphylococcus aureus in four patients, Pseudomonas spp. in three, and Escherichia coli in one patient. Diabetes mellitus and perioperative transfusion with allogeneic blood were not predictive of SSI. Duration of operation longer than 120 minutes was a strong predictor (OR 2.25, 95% CL 0.48-10.16). Other risk factors were male sex (OR 2.01, 95% CL 0.44-10.45), injury-operation interval less than six months (OR 2.00, 95% CL 0.22-46.08), fracture fixation with plates and screws (OR 1.51, 95% CL 0.36-6.40), white blood cell count (WBC) less than 5,000 per cumm (OR 1.50, 95% CL 0.15-16.37), preoperative urinary catheterization (OR 1.48, 95% CL 0.00-16.19), and postoperative urinary catheterization (OR 1.24, 95% CL 0.29-5.00). CONCLUSION: The incidence of SSI after internal fixation of long bone fractures in our centers is 12%, and this is within the previously reported range. Use of plates and screws, WBC less than 5,000 per cumm, and perioperative urinary catheterization are important risk factors. PMID:15303412

  9. An electronically instrumented internal fixator for the assessment of bone healing

    PubMed Central

    Kowald, B.; Seide, K.; Aljudaibi, M.; Faschingbauer, M.; Juergens, C.; Gille, J.

    2016-01-01

    Objectives The monitoring of fracture healing is a complex process. Typically, successive radiographs are performed and an emerging calcification of the fracture area is evaluated. The aim of this study was to investigate whether different bone healing patterns can be distinguished using a telemetric instrumented femoral internal plate fixator. Materials and Methods An electronic telemetric system was developed to assess bone healing mechanically. The system consists of a telemetry module which is applied to an internal locking plate fixator, an external reader device, a sensor for measuring externally applied load and a laptop computer with processing software. By correlation between externally applied load and load measured in the implant, the elasticity of the osteosynthesis is calculated. The elasticity decreases with ongoing consolidation of a fracture or nonunion and is an appropriate parameter for the course of bone healing. At our centre, clinical application has been performed in 56 patients suffering nonunion or fracture of the femur. Results A total of 39 cases of clinical application were reviewed for this study. In total, four different types of healing curves were observed: fast healing; slow healing; plateau followed by healing; and non-healing. Conclusion The electronically instrumented internal fixator proved to be valuable for the assessment of bone healing in difficult healing situations. Cost-effective manufacturing is possible because the used electronic components are derived from large-scale production. The incorporation of microelectronics into orthopaedic implants will be an important innovation in future clinical care. Cite this article: B. Kienast, B. Kowald, K. Seide, M. Aljudaibi, M. Faschingbauer, C. Juergens, J. Gille. An electronically instrumented internal fixator for the assessment of bone healing. Bone Joint Res 2016;5:191–197. DOI: 10.1302/2046-3758.55.2000611. PMID:27226357

  10. Buckling behavior of long anisotropic plates subjected to combined loads

    NASA Technical Reports Server (NTRS)

    Nemeth, Michael P.

    1995-01-01

    A parametric study is presented of the buckling behavior of infinitely long symmetrically laminated anisotropic plates subjected to combined loads. The study focuses on the interaction of a subcritical (stable) secondary loading state of constant magnitude and a primary destabilizing load that is increased in magnitude until buckling occurs. The loads, considered in this report are uniform axial compression, pure in-plane bending, transverse tension and compression, and shear. Results are presented that were obtained by using a special purpose nondimensional analysis that is well suited for parametric studies of clamped and simply supported plates. In particular, results are presented for a +/- 45(sub S) graphite-epoxy laminate that is highly anisotropic and representative of a laminate used for spacecraft applications. In addition, generic buckling-design charts are presented for a wide range of nondimensional parameters that are applicable to a broad class of laminate constructions. These results show the general behavioral trends of specially orthotropic plates and the effects of flexural anisotropy on plates subjected to various combined loading conditions. An important finding of the present study is that the effects of flexural anisotropy on the buckling resistance of a plate can be significantly more important for plates subjected to combined loads than for plates subjected to single-component loads.

  11. Finite element analysis of three patterns of internal fixation of fractures of the mandibular condyle.

    PubMed

    Aquilina, Peter; Chamoli, Uphar; Parr, William C H; Clausen, Philip D; Wroe, Stephen

    2013-06-01

    The most stable pattern of internal fixation for fractures of the mandibular condyle is a matter for ongoing discussion. In this study we investigated the stability of three commonly used patterns of plate fixation, and constructed finite element models of a simulated mandibular condylar fracture. The completed models were heterogeneous in the distribution of bony material properties, contained about 1.2 million elements, and incorporated simulated jaw-adducting musculature. Models were run assuming linear elasticity and isotropic material properties for bone. This model was considerably larger and more complex than previous finite element models that have been used to analyse the biomechanical behaviour of differing plating techniques. The use of two parallel 2.0 titanium miniplates gave a more stable configuration with lower mean element stresses and displacements over the use of a single miniplate. In addition, a parallel orientation of two miniplates resulted in lower stresses and displacements than did the use of two miniplates in an offset pattern. The use of two parallel titanium plates resulted in a superior biomechanical result as defined by mean element stresses and relative movement between the fractured fragments in these finite element models.

  12. Arthroscopically assisted percutaneous fixation of Bennett fractures.

    PubMed

    Culp, Randall W; Johnson, Jeff W

    2010-01-01

    Arthroscopic-assisted reduction and fixation of Bennett-type fractures of the thumb metacarpal allow for the confirmation of reduction as well as the assessment of the degree of chondral damage. With use of a 1.9-mm arthroscope and a traction tower, direct visualization and reduction is possible. Traditional methods of fixation are used to secure the fracture fragment. Postoperative rehabilitation follows the usual protocol used in both open and percutaneous techniques. However, the potential to obtain and confirm a more accurate articular reduction may reduce the incidence of late arthritis of the thumb carpometacarpal articulation.

  13. [Macroscopic and functional anatomy of the apophyseal plate].

    PubMed

    Putz, R; Milz, S

    2016-03-01

    Apophyses are growth zones attached to the shaft (corpus) of larger bones. They vary in size and develop their own ossification centres or form as part of an usually fibrocartilaginous tendon or ligament insertion. The structure of the cartilaginous apophyseal plate is very similar to that of an epiphyseal growth plate and like these they are adapted to withstand perpendicular compressive forces without becoming harmed. This is best highlighted by the fact that their mineralized borders always orient themselves perpendicular to the overall resulting force vector. The edges of the apophyseal plates are characteristically bent which allows them to resist moderate shear forces. Like the epiphyseal plates the apophyseal plates exhibit a zonal organization which is not very well adapted to permanently withstand shear forces, especially if they occur under dynamic conditions. In these situations the tendinous insertions with their collagen fibre anchoring system have to provide compensation when balancing the load transmitted across the system.

  14. Design of laminated composite plates for maximum shear buckling loads

    SciTech Connect

    Chang, R.R.; Chu, K.H.; Kam, T.Y.

    1993-12-01

    The optimal lamination arrangements of laminated composite plates with maximum shear buckling loads are studied via a multi-start global optimization technique. A previously proposed shear deformable finite element is used to evaluate the positive and negative shear buckling loads of laminated composite plates in the optimal design process. Optimal lay-ups of thin as well as moderately thick composite plates with global maximum positive or negative shear buckling loads are determined utilizing the multi-start global optimal design technique. A number of examples of the optimal shear buckling design of symmetrically and antisymmetrically laminated composite plates with various material properties, length-to-thickness ratios, aspect ratios and different numbers of layer groups are given to illustrate the trends of optimal layer orientations of the plates. Since the existence of in-plane axial force is possible, the effects of axial compressive load on the optimal layer orientations for maximum shear buckling load are also investigated.

  15. Outcome of percutaneous balloon kyphoplasty in vertebral compression fractures

    PubMed Central

    Saxena, B Praveen; Shah, B Viral; Joshi, S Prateek

    2015-01-01

    Background: Incidence of vertebral compression fractures (VCFs) is increasing due to increase in human life expectancy and prevalence of osteoporosis. Vertebroplasty had been traditional treatment for pain, but it neither attempts to restore vertebral body height nor eliminates spinal deformity and is associated with a high rate of cement leakage. Balloon kyphoplasty involves introduction of inflatable balloon into the fractured body of vertebra for elevation of the end-plates prior to fixation of the fracture with bone cement. This study evaluates short term functional and radiological outcomes of balloon kyphoplasty. The secondary aim is to explore short-term complications of the procedure. Materials and Methods: A retrospective study of 199 kyphoplasty procedures in 135 patients from March 2009 to March 2012 were evaluated with short form-36 (SF-36) score, visual analogue scale (VAS), detailed neurological and radiological evaluations. The mean followup was 18 months (range 12–20 months). Statistical analysis including paired sample t-test was done with statistical package for social sciences. Results: Statistically significant improvements in SF-36 (from 34.29 to 48.53, an improvement of 14.24, standard deviation (SD) - 20.08 P < 0.0001), VAS (drop of 4.49, from 6.74 to 2.24, SD - 1.44, P < 0.0001), percentage restoration of lost vertebral height (from 30.62% to 16.19%, improvement of 14.43%, SD - 15.37, P < 0.0001) and kyphotic angle correction (from 17.41° to 10.59°, improvement of 6.82, SD - 7.26°, P < 0.0001) were noted postoperatively. Six patients had cement embolism, 65 had cement leak and three had adjacent level fracture which required repeat kyphoplasty later. One patient with history of ischemic heart disease had cardiac arrest during the procedure. No patients had neurological deterioration in the followup period. Conclusions: Kyphoplasty is a safe and effective treatment for VCFs. It improves physical function, reduces pain and corrects

  16. Vascular compression syndromes.

    PubMed

    Czihal, Michael; Banafsche, Ramin; Hoffmann, Ulrich; Koeppel, Thomas

    2015-11-01

    Dealing with vascular compression syndromes is one of the most challenging tasks in Vascular Medicine practice. This heterogeneous group of disorders is characterised by external compression of primarily healthy arteries and/or veins as well as accompanying nerval structures, carrying the risk of subsequent structural vessel wall and nerve damage. Vascular compression syndromes may severely impair health-related quality of life in affected individuals who are typically young and otherwise healthy. The diagnostic approach has not been standardised for any of the vascular compression syndromes. Moreover, some degree of positional external compression of blood vessels such as the subclavian and popliteal vessels or the celiac trunk can be found in a significant proportion of healthy individuals. This implies important difficulties in differentiating physiological from pathological findings of clinical examination and diagnostic imaging with provocative manoeuvres. The level of evidence on which treatment decisions regarding surgical decompression with or without revascularisation can be relied on is generally poor, mostly coming from retrospective single centre studies. Proper patient selection is critical in order to avoid overtreatment in patients without a clear association between vascular compression and clinical symptoms. With a focus on the thoracic outlet-syndrome, the median arcuate ligament syndrome and the popliteal entrapment syndrome, the present article gives a selective literature review on compression syndromes from an interdisciplinary vascular point of view.

  17. The role of elastic compressibility in dynamic subduction models

    NASA Astrophysics Data System (ADS)

    Austmann, W.; Govers, R. M.

    2013-12-01

    Recent advances in geodynamic numerical models show a trend towards more realistic rheologies. The Earth is no longer modeled as a purely viscous fluid, but the effects of, for example, elasticity and plasticity are also included. However, by making such improvements, it is essential to include these more complex rheologies in a consistent way. Specifically, compressibility needs also to be included, an effect that is commonly neglected in numerical models. Recently, we showed that the effect of elastic compressibility is significant. This was done for a gravity driven cylinder in a homogeneous Maxwell fluid bounded by closed boundaries. For a fluid with a realistic compressibility (Poisson ratio equals 0.3), the settling velocity showed a discrepancy with the semi-analytical steady state incompressible solution of approximately 40%. The motion of the fluid was no longer restricted by a small region around the cylinder, but the motion of the cylinder compressed also the fluid near the bottom boundary. This compression decreased the resistance on the cylinder and resulted in a larger settling velocity. Here, we examine the influence of elastic compressibility in an oceanic subduction setting. The slab is driven by slab pull and a far field prescribed plate motion. Preliminary results indicate that elastic compressibility has a significant effect on the fluid motion. Differences with respect to nearly incompressible solution are most significant near material boundaries. In line with our earlier findings, the flow is increased in regions of confined flow, such as the mantle wedge or the subduction channel. As a consequence, an increasing compressibility results in a larger slab velocity. We seek to identify surface observables, such as topography and plate motion, that allow us to distinguish the compressible and incompressible behavior.

  18. The role of elastic compressibility in dynamic subduction models

    NASA Astrophysics Data System (ADS)

    Austmann, Walter; Govers, Rob; Burov, Evgenii

    2014-05-01

    Recent advances in geodynamic numerical models show a trend towards more realistic rheologies. The Earth is no longer modeled as a purely viscous fluid, but the effects of, for example, elasticity and plasticity are also included. However, by making such improvements, it is essential to include these more complex rheologies in a consistent way. Specifically, compressibility needs also to be included, an effect that is commonly neglected in numerical models. Recently, we showed that the effect of elastic compressibility is significant. This was done for a gravity driven cylinder in a homogeneous Maxwell fluid bounded by closed boundaries. For a fluid with a realistic compressibility (Poisson ratio equals 0.3), the settling velocity showed a discrepancy with the semi-analytical steady state incompressible solution of approximately 40%. The motion of the fluid was no longer restricted by a small region around the cylinder, but the motion of the cylinder compressed also the fluid near the bottom boundary. This compression decreased the resistance on the cylinder and resulted in a larger settling velocity. Here, we examine the influence of elastic compressibility in an oceanic subduction setting. The slab is driven by slab pull and a far field prescribed plate motion. Preliminary results indicate that elastic compressibility has a significant effect on the fluid motion. Differences with respect to nearly incompressible solution are most significant near material boundaries. In line with our earlier findings, the flow is increased in regions of confined flow, such as the mantle wedge or the subduction channel. As a consequence, an increasing compressibility results in a larger slab velocity. We seek to identify surface observables, such as topography and plate motion, that allow us to distinguish the compressible and incompressible behavior.

  19. Temporary scaphocapitate fixation with or without radial shortening for adolescent Kienböck's disease.

    PubMed

    Cha, Soo Min; Shin, Hyun Dae; Ahn, Jae Sung; Noh, Chang Kyun

    2015-05-01

    We performed temporary scaphocapitate joint fixation with or without radial shortening osteotomy, depending on the ulnar variance, in adolescent Kienböck's disease. The aim of the current study was to evaluate the radiological and clinical results and compare our results with those of other previously reported methods. Temporary scaphocapitate fixation alone or fixation accompanied by radial shortening osteotomy has been performed in three patients since 2003. All six patients were males, and their mean age at surgery was 15.5 years. The fixation was performed using two Kirschner-wires in closed methods, and the shortening of the radius was performed using the volar approach and secured with a plate. Radial shortenings of 4, 2, and 7 mm were applied. Radiological findings of Kienböck's disease, including ulnar variance and carpal height ratio, were investigated at the final follow-up by simple radiography and MRI. Clinical results of pain, range of wrist motion, and grip strength were also evaluated. The mean age at the final follow-up of six patients was 22 years, and the follow-up period was 6.8 years. Sclerosis or fragmentation of all the lunates in the simple radiographs improved, and the carpal height ratio increased to 0.5 at the final follow-up. The signal intensities on the final MRI were all normalized. The final visual analog scale scores decreased to 1.2, and wrist ranges of motion were all statistically significantly increased. In addition, grip strength increased to 69% of that of the normal side at the final follow-up. We suggest that temporary scaphocapitate joint fixation is a recommendable option with or without radial shortening, depending on the ulnar variance, in adolescent Kienböck's disease.

  20. Anatomic Study of Anterior Transdiscal Axial Screw Fixation for Subaxial Cervical Spine Injuries.

    PubMed

    Ji, Wei; Zheng, Minghui; Qu, Dongbin; Zou, Lin; Chen, Yongquan; Chen, Jianting; Zhu, Qingan

    2016-08-01

    Anterior transdiscal axial screw (ATAS) fixation is an alternative or supplement to the plate and screw constructs for the upper cervical spine injury. However, no existing literatures clarified the anatomic feasibility of this technique for subaxial cervical spine. Therefore, the objective of this study was to evaluate the anatomical feasibility and to establish guidelines for the use of the ATAS fixation for the subaxial cervical spine injury.Fifty normal cervical spines had radiographs to determine the proposed screw trajectory (the screw length and insertion angle) and the interbody graft-related parameters (the disc height and depth, and the distance between anterior vertebral margin and the screw) for all levels of the subaxial cervical spine. Following screw insertion in 8 preserved human cadaver specimens, surgical simulation and dissection verified the feasibility and safety of the ATAS fixation.Radiographic measurements showed the mean axial screw length and cephalic incline angle of all levels were 41.2 mm and 25.2°, respectively. The suitable depth of the interbody graft was >11.7 mm (the distance between anterior vertebral margin and the screw), but <17.1 mm (disc depth). Except the axial screw length, increase in all the measurements was seen with level up to C5-C6 segment. Simulated procedure in the preserved specimens demonstrated that ATAS fixation could be successfully performed at C2-C3, C3-C4, C4-C5, and C5-C6 levels, but impossible at C6-C7 due to the obstacle of the sternum. All screws were placed accurately. None of the screws penetrated into the spinal canal and caused fractures determined by dissecting the specimens.The anterior transdiscal axial screw fixation, as an alternative or supplementary instrumentation for subaxial cervical spine injuries, is feasible and safe with meticulous surgical planning.

  1. GOLD PLATING PROCESS

    DOEpatents

    Seegmiller, R.

    1957-08-01

    An improved bath is reported for plating gold on other metals. The composition of the plating bath is as follows: Gold cyanide from about 15 to about 50 grams, potassium cyanide from about 70 to about 125 grams, and sulfonated castor oil from about 0.1 to about 10 cc. The gold plate produced from this bath is smooth, semi-hard, and nonporous.

  2. Plating methods, a survey

    NASA Technical Reports Server (NTRS)

    Berkowitz, J. B.; Emerson, N. H.

    1972-01-01

    Results are presented of a comprehensive search of the literature available, much of which has been generated by the research centers of NASA and its contractors, on plating and coating methods and techniques. Methods covered included: (1) electroplating from aqueous solutions; (2) electroplating from nonaqueous solutions; (3) electroplating from fused-salt baths; (4) electroforming; (5) electroless plating, immersion plating, and mirroring; (6) electroplating from gaseous plasmas; and (7) anodized films and conversion coatings.

  3. Dental Compressed Air Systems.

    DTIC Science & Technology

    1992-03-01

    I AL-TR-IWI-0uuu AD-A249 954 DENTAL COMPRESSED AIMYTM R Curtis D. Weyrmuch, Mejor, USAP, D Samuel P.Dvs iueatclpi SF.O N AEROSPACE MwaEDIN mwr~ComA G...FUNDING NUMBERS Dental Compressed Air Systems PE - 87714F PR - 7350 TA - 22 D. Weyrauch WU - XX Samuel P. Davis George W. Gaines 7. PERFORMING...words) The purpose of this report is to update guidelines on dental compressed air systems (DCA). Much of the information was obtained from a survey

  4. Modeling Compressed Turbulence

    SciTech Connect

    Israel, Daniel M.

    2012-07-13

    From ICE to ICF, the effect of mean compression or expansion is important for predicting the state of the turbulence. When developing combustion models, we would like to know the mix state of the reacting species. This involves density and concentration fluctuations. To date, research has focused on the effect of compression on the turbulent kinetic energy. The current work provides constraints to help development and calibration for models of species mixing effects in compressed turbulence. The Cambon, et al., re-scaling has been extended to buoyancy driven turbulence, including the fluctuating density, concentration, and temperature equations. The new scalings give us helpful constraints for developing and validating RANS turbulence models.

  5. Posterior fixation suture and convergence excess esotropia.

    PubMed

    Steffen; Auffarth; Kolling

    1998-09-01

    The present study investigates the results of Cuppers' 'Fadenoperation' in patients with non-accommodative convergence excess esotropia. Particular attention is given to postoperative eye alignment at distance fixation. Group 1 (n=96) included patients with a 'normal' convergence excess. The manifest near angles (mean ET 16.73 degrees +/- 6.33 degrees, range 4 degrees -33 degrees ) were roughly twice the size of the distance angles (mean ET 6.50 degrees +/- 3.62 degrees, range 0 degrees -14 degrees ). These patients were treated with a bilateral fadenoperation of the medial recti without additional eye muscle surgery. Three months after surgery, the mean postoperative angles were XT 0.5 degrees +/- 3.3 degrees (range XT 11 degrees -ET 5 degrees ) for distance fixation, and ET 2.7 degrees +/- 3.6 degrees (range XT 5 degrees -ET 14 degrees ) for near fixation, respectively. Postoperative convergent angles at near fixation >ET 10 degrees were present in two patients (1.9%). Group 2 (n=21) included patients with a mean preoperative distance angle of ET 9.2 degrees +/- 3.7 degrees (range 6 degrees -16 degrees ) and a mean preoperative near angle of ET 23.4 degrees +/- 3.1 degrees (range 16 degrees -31 degrees ). These patients were operated on with a bilateral fadenoperation of the medial recti and a simultaneous recession of one or both medial rectus muscles. Mean postoperative angles were XT 0.5 degrees +/- 4.6 degrees (range XT 12 degrees -ET 7 degrees ) for distance fixation and ET 1.4 degrees +/- 4.5 degrees (range XT 8 degrees -ET 13 degrees ) for near fixation, respectively. In this group, 2 patients (10.6%) had a postoperative exotropia >XT 5 degrees at distance fixation, and two patients had residual esotropia>ET 10 degrees at near fixation. Group 3 (n=17) included patients with a pronounced non-accommodative convergence excess. Near angle values (mean of 17.8 degrees +/- 5.3 degrees, range ET 7 degrees -26 degrees ) were several times higher than the distance

  6. Recoil Experiments Using a Compressed Air Cannon

    NASA Astrophysics Data System (ADS)

    Taylor, Brett

    2006-12-01

    Ping-Pong vacuum cannons, potato guns, and compressed air cannons are popular and dramatic demonstrations for lecture and lab.1-3 Students enjoy them for the spectacle, but they can also be used effectively to teach physics. Recently we have used a student-built compressed air cannon as a laboratory activity to investigate impulse, conservation of momentum, and kinematics. It is possible to use the cannon, along with the output from an electronic force plate, as the basis for many other experiments in the laboratory. In this paper, we will discuss the recoil experiment done by our students in the lab and also mention a few other possibilities that this apparatus could be used for.

  7. Caudally directed Inferior facetal and transfacetal screws for C1-C2 and C1-2-3 fixation.

    PubMed

    Goel, Atul

    2017-01-13

    An alternative caudally directed C2 inferior facetal screw is described. Such screw insertion can form the axial stabilization point in cases undergoing atlantoaxial lateral mass plate/rod and screw fixation and those undergoing C1-2and C1-2-3 spinal fixation. The C2 screw courses from the medial point of pedicle-laminar junction and travels caudally and laterally towards the C2-3 articulation. Deploying a longer screw that traverses in a transarticular fashion into the facetal mass of C3 vertebra one can perform C1-2-3 stabilization.Sixteen patients underwent C2 inferior facetal or C2-3 transarticular screw in combination with C1 screw for atlantoaxial fixation. Three of these patients with multilevel spinal instability underwent atlantoaxial and C2-3 fixation using the discussed technique. The technical issues, anatomical subtleties and indication for the use of the C2 inferior facetal screws are discussed. With an average follow-up of 9 months, all screws have successfully provided stability that resulted in arthrodesis of the treated spinal segments. Caudally directed C2 inferior facetal screw can enhance the armamentarium of the surgeon, provide an alternative to conventional techniques or a bailout option and add to safety of the procedure of atlantoaxial lateral mass fixation in anatomically challenged situations.

  8. Progressive Failure Analysis of Laminated Composite Plates with Elliptical or Circular Cutout Using Finite Element Method

    NASA Astrophysics Data System (ADS)

    Lakshminarayana, A.; Vijayakumar, R.; Krishnamohana Rao, G.

    2016-09-01

    The progressive failure analysis of symmetrically laminated composite plate [0°/+45°/-45°/90°]2s with circular or elliptical cutout under uniform uniaxial compression loading is carried out using finite element method. Hashin's failure criterion is used to predict the lamina failure. A parametric study has been carried out to study the effect of elliptical / circular cutout orientation, cutout size and plate thickness on the ultimate failure load of laminated composite plate under uni-axial compression loading. It is noticed that elliptical cutout orientation has influence on the strength of the notched composite plates. It is observed that the laminate size of the elliptical/circular cutout and plate thickness has substantial influence on the ultimate failure load of notched composite plates.

  9. A solution procedure for behavior of thick plates on a nonlinear foundation and postbuckling behavior of long plates

    NASA Technical Reports Server (NTRS)

    Stein, M.; Stein, P. A.

    1978-01-01

    Approximate solutions for three nonlinear orthotropic plate problems are presented: (1) a thick plate attached to a pad having nonlinear material properties which, in turn, is attached to a substructure which is then deformed; (2) a long plate loaded in inplane longitudinal compression beyond its buckling load; and (3) a long plate loaded in inplane shear beyond its buckling load. For all three problems, the two dimensional plate equations are reduced to one dimensional equations in the y-direction by using a one dimensional trigonometric approximation in the x-direction. Each problem uses different trigonometric terms. Solutions are obtained using an existing algorithm for simultaneous, first order, nonlinear, ordinary differential equations subject to two point boundary conditions. Ordinary differential equations are derived to determine the variable coefficients of the trigonometric terms.

  10. PLATES WITH OXIDE INSERTS

    DOEpatents

    West, J.M.; Schumar, J.F.

    1958-06-10

    Planar-type fuel assemblies for nuclear reactors are described, particularly those comprising fuel in the oxide form such as thoria and urania. The fuel assembly consists of a plurality of parallel spaced fuel plate mennbers having their longitudinal side edges attached to two parallel supporting side plates, thereby providing coolant flow channels between the opposite faces of adjacent fuel plates. The fuel plates are comprised of a plurality of longitudinally extending tubular sections connected by web portions, the tubular sections being filled with a plurality of pellets of the fuel material and the pellets being thermally bonded to the inside of the tubular section by lead.

  11. CALUTRON FACE PLATE

    DOEpatents

    Brobeck, W.M.

    1959-08-25

    The construction of a removable cover plate for a calutron tank is described. The plate is fabricated of a rectangular frame member to which is welded a bowed or dished plate of thin steel, reinforced with transverse stiffening ribs. When the tank is placed between the poles of a magnet, the plate may be pivoted away from the tank and magnet and is adapted to support the ion separation mechanism secured to its inner side as well as the vacuum load within the tank.

  12. [Osteosynthesis of subcondylar fractures using compression screws with the Eckelt technic. Experiences and difficulties with the technic over 5 years].

    PubMed

    Maladière, E; Chikhani, L; Meningaud, J P; Favre, E; Bertrand, J C; Guilbert, F

    1999-05-01

    With creation of new fixation material, the surgical treatment of displaced subcondylar fractures is most frequently used in adults. The Eckelt compression osteosynthesis is described as an easy procedure in the current literature, but, in our experience, several problems require our attention. We report the treatment of 57 patients with displaced subcondylar fractures where compression osteosynthesis was indicated. The difficulty of this technique is presented on the basis of a 5-years experience.

  13. Failure waves in shock-compressed glasses

    NASA Astrophysics Data System (ADS)

    Kanel, Gennady I.

    2005-07-01

    The failure wave is a network of cracks that are nucleated on the surface and propagate into the elastically stressed body. It is a mode of catastrophic fracture in an elastically stressed media whose relevance is not limited to impact events. In the presentation, main properties of the failure waves are summarized and discussed. It has been shown that the failure wave is really a wave process which is characterized by small increase of the longitudinal stress and corresponding increments of the particle velocity and the density. The propagation velocity of the failure wave is less than the sound speed; it is not directly related to the compressibility but is determined by the crack growth speed. Transformation of elastic compression wave followed by the failure wave in a thick glass plate into typical two-wave configuration in a pile of thin glass plates confirms crucial role of the surfaces. The latter, as well as specific kinematics of the process distinguishes the failure wave from a time-dependent inelastic compressive behavior of brittle materials. The failure wave is steady if the stress state ahead of it is supported unchanging. Mechanism of this self-supporting propagation of compressive fracture is not quite clear as yet. On the other hand, collected data about its kinematics allow formulating phenomenological models of the phenomenon. In some sense the process is similar to the diffusion of cracks from a source on the glass surface. However, the diffusion-like models contradict to observed steady propagation of the failure wave. Analogy with a subsonic combustion wave looks more fruitful. Computer simulations based on the phenomenological combustion-like model reproduces well all kinematical aspects of the phenomenon.