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1

Complications after volar locking plate fixation of distal radius fractures.  

PubMed

Volar locking plates are an increasingly popular treatment for distal radius fractures. We reviewed complications observed after volar locking plate fixation in a busy teaching hospital. The purpose of the study was to assess whether complication rates after volar locking plate use in general, routine trauma practice were higher than published literature from expert users. A retrospective review was carried out of patients treated with a volar locking plate between January 2009 and December 2010. The series included 206 procedures in 204 patients (77 males and 127 females) with mean age of 55 years (range 16-94). Surgery was performed by 18 different consultant surgeons and 11 registrars. A total of 22 complications were observed in 20 patients with an overall complication rate of 9.7%. Seven (3.4%) patients developed tendon problems including four (1.9%) tendon ruptures. Four (1.9%) patients required re-operation for metalwork problems; four patients developed complex regional pain syndrome (CRPS). Three fracture reduction problems were noted. A total of 16 further operations were carried out for complications. The overall complication rate was low even when surgery was done by many surgeons, suggesting that this is a safe and reproducible technique. This study provides information which can be used to counsel patients about risks, including those of tendon and metalwork problems. This allows patients to make an informed decision. Surgeons must have specific strategies to avoid these complications and remain vigilant so that these can be identified and managed early. PMID:24176679

Johnson, N A; Cutler, L; Dias, J J; Ullah, A S; Wildin, C J; Bhowal, B

2014-03-01

2

The effect of fracture stability on the performance of locking plate fixation in periprosthetic femoral fractures.  

PubMed

Periprosthetic femoral fracture (PFF) fixation failures are still occurring. The effect of fracture stability and loading on PFF fixation has not been investigated and this is crucial for optimum management of PFF. Models of stable and unstable PPFs were developed and used to quantify the effect of fracture stability and loading in a single locking plate fixation. Stress on the plate was higher in the unstable compared to the stable fixation. In the case of unstable fractures, it is possible for a single locking plate fixation to provide the required mechanical environment for callus formation without significant risk of plate fracture, provided partial weight bearing is followed. In cases where partial weight bearing is unlikely, additional biological fixation could be considered. PMID:23642449

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

2013-10-01

3

Locking compression plate distal ulna hook plate as alternative fixation for fifth metatarsal base fracture.  

PubMed

Intramedullary screw fixation has been the most common treatment for fifth metatarsal base fractures. However, screw application will not achieve accurate reduction in fractures with small fragments, osteoporotic bone, or Lawrence zone 1 fractures. Because of the similar anatomic architecture between the distal ulna and the fifth metatarsal base, the purpose of the present study was to assess the results of a locking compression plate distal ulna hook plate in stabilizing displaced zone 1 or 2 fifth metatarsal base fractures. A total of 19 patients with Lawrence zone 1 (n = 12) or 2 (n = 7) fractures of the fifth metatarsal base were treated surgically with a locking compression plate distal ulna hook plate. The patients were evaluated clinically and radiographically, and the functional outcomes were graded using the American Orthopaedic Foot and Ankle Society midfoot scoring system. Radiographic bony union was obtained in all patients, at an average of 7.4 weeks. The mean American Orthopaedic Foot and Ankle Society midfoot score improved from 26 (range 0 to 45) points preoperatively to 94 (range 72 to 100) points at the final follow-up visit. Three patients developed post-traumatic cubometatarsal arthrosis, and 1 patient developed sural nerve neurapraxia. In our experience, the distal ulna hook plate achieved a high rate of bony consolidation and anatomically suitable fixation in zone 1 or 2 fifth metatarsal base fractures. We suggest that the locking compression plate distal ulna hook plate should be considered as an alternative treatment of multifragmentary, osteoporotic, and tuberosity avulsion (zone 1) fifth metatarsal base fractures. PMID:24713494

Lee, Sang Ki; Park, Ju Sang; Choy, Won Sik

2014-01-01

4

Load Sharing Mechanism Across Graft-Bone Interface in Static Cervical Locking Plate Fixation  

PubMed Central

Objective This study is a retrospective clinical study over more than 4 years of follow up to understand the mechanism of load sharing across the graft-bone interface in the static locking plate (SLP) fixation compared with non-locking plate (NLP). Methods Orion locking plates and Top non-locking plates were used for SLP fixation in 29 patients and NLP fixation in 24 patients, respectively. Successful interbody fusion was estimated by dynamic X-ray films. The checking parameters were as follows : screw angle (SA) between upper and lower screw, anterior and posterior height of fusion segment between upper and lower endplate (AH & PH), and upper and lower distance from vertebral endplate to the end of plate (UD & LD). Each follow-up value of AH and PH were compared to initial values. Contributions of upper and lower collapse to whole segment collapse were estimated. Results Successful intervertebral bone fusion rate was 100% in the SLP group and 92% in the NLP group. The follow-up mean value of SA in SLP group was not significantly changed compared with initial value, but follow-up mean value of SA in NLP group decreased more than those in SLP group (p=0.0067). Statistical analysis did not show a significant difference in the change in AH and PH between SLP and NLP groups (p>0.05). Follow-up AH of NLP group showed more collapse than PH of same group (p=0.04). The upper portion of the vertebral body collapsed more than the lower portion in the SLP fixation (p=0.00058). Conclusion The fused segments with SLP had successful bone fusion without change in initial screw angle, which was not observed in NLP fixation. It suggests that there was enough load sharing across bone-graft interface in SLP fixation. PMID:19444346

Han, In Ho; Kuh, Sung Uk; Chin, Dong Kyu; Jin, Byung Ho; Cho, Yong Eun

2009-01-01

5

Locked plate fixation of the comminuted distal fibula: a biomechanical study  

PubMed Central

Background The purpose of this study was to compare the biomechanical properties of locked versus nonlocked lateral fibular bridge plating of comminuted, unstable ankle fractures in a mode of catastrophic failure. Methods We created comminuted Weber C fractures in 8 paired limbs from fresh cadavers. Fractures were plated with either standard or locked one-third tubular bridge plating techniques. Specimens were biomechanically evaluated by external rotation to failure while subjected to a compressive load approximating body weight. We measured the angle to failure, torque to failure, energy to failure and construct stiffness. Results There was no significant difference in construct stiffness or other biomechanical properties between locked and standard one-third tubular plating techniques. Conclusion We found no difference in biomechanical properties between locked and standard bridge plating of a comminuted Weber C fibular fracture in a model of catastrophic failure. It is likely that augmentation of fixation with K-wires or trans-tibial screws provides a construct superior to locked bridge plating alone. Further biomechanical and clinical analysis is required to improve understanding of the role of locked plating in ankle fractures and in osteoporotic bone. PMID:23187038

White, Neil J.; Corr, David T.; Wagg, James P.; Lorincz, Caeley; Buckley, Richard E.

2013-01-01

6

Early outcomes of proximal humerus fracture fixation with locking plate and intramedullary fibular strut graft.  

PubMed

Proximal humerus fractures are commonly encountered in elderly patients. Surgical treatment demonstrates high complication rates, including varus construct collapse and screw cutout. In this study, the authors evaluate the clinical outcome of locking plate fixation with intramedullary fibular strut graft augmentation as a primary surgical treatment in the prevention of early collapse and screw cutout. A total of 9 patients were evaluated. Surgery was performed for displaced proximal humerus fractures between April and December 2011. Patients were either class 2, 3, or 4, according to Neer classification. Mean patient age was 75.4 years. Preoperative and immediate, 6-week, and 3-month postoperative radiographs were evaluated. Head-shaft angles were measured to assess for varus collapse and displacement. Range of motion, complication rates, and functional recovery were also evaluated. Patients underwent open reduction and internal fixation with placement of an intramedullary fibular strut graft. Fixation was achieved with a Philos plate (Synthes, Oberdorf, Switzerland). Reduction and fixation were evaluated with radiographs. Passive exercises and range of motion were allowed immediately postoperatively, and all patients achieved active abduction and forward flexion 6 weeks postoperatively. Shoulder radiographs taken 12 weeks postoperatively revealed no loss of reduction or screw cutout. The introduction of the locking plate has improved outcomes. The addition of an intramedullary strut graft has shown improved preliminary results. Maintained reduction was observed in all 9 patients in the early postoperative period, and good functional motion was achieved. No incidence of screw cutout was recorded. PMID:25350626

Tan, Edwin; Lie, Denny; Wong, M K

2014-09-01

7

Locking compression plate fixation of radial and tibial fractures in a young dog.  

PubMed

A six-month-old, male Bernese Mountain Dog in which radius-ulna and tibia-fibula concomitant fractures were treated each with a 3.5 mm Locking Compression Plate (LCP) is presented. Both fractures were approached and plated medially. The tibial fracture had to be revised with a 4.5 mm intramedullary nail and a new 3.5 mm LCP at the second post-operative day because of fixation breakdown. The follow-up radiographs taken at days 14 and 53 revealed uneventful healing of both fractures. Implants were removed 53 days after surgery. PMID:16594453

Schwandt, C S; Montavon, P M

2005-01-01

8

Comparison of locked plate fixation and nonoperative management for displaced proximal humerus fractures in elderly patients.  

PubMed

Use of locked plate fixation for proximal humerus fractures in elderly patients has increased markedly in recent years. We conducted a study to compare outcomes of operative (locked plate fixation) and nonoperative management of these fractures. From our database, we identified 207 displaced proximal humerus fractures that met all inclusion and exclusion criteria. For patients who accepted our invitation to return for evaluation, clinical outcome was assessed using several questionnaires: Constant; DASH (Disabilities of the Arm, Shoulder, and Hand); SMFA (Short Musculoskeletal Functional Assessment); and Patient Reported Outcomes Measurement Information System (PROMIS) Physical Function Computer Adaptive Test. Of the 207 patients, 61 were managed operatively and 146 nonoperatively. Operative patients had lower rates of malunion but higher rates of complications, which included screw perforation, loss of fixation, infection, and secondary surgical procedures. Forty-seven patients (a mix of operative and nonoperative) accepted our invitation to return for clinical evaluation at a mean follow-up of 3.3 years. The 2 groups' clinical outcomes were similar. PMID:25844592

Okike, Kanu; Lee, Olivia C; Makanji, Heeren; Morgan, Jordan H; Harris, Mitchel B; Vrahas, Mark S

2015-04-01

9

Fixation of the Lapidus arthrodesis with a plantar interfragmentary screw and medial low profile locking plate.  

PubMed

The Lapidus arthrodesis can be used to correct pathology within the forefoot or midfoot, and severe hallux valgus deformities as well as hypermobility of the medial column may be amenable to correction with this procedure. Many different skeletal fixation methods have been described for this procedure, and one form that appears to provide enough construct stability to allow patients to bear weight early in the postoperative period is described herein. This construct consists of an interfragmental compression screw oriented from the plantar aspect of the first metatarsal to the superior aspect of the medial cuneiform, with medial locking plate augmentation. PMID:22632842

Cottom, James M

2012-01-01

10

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

PubMed

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. PMID:23636756

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

2013-07-01

11

Wrist function recovers more rapidly after volar locked plating than after external fixation but the outcomes are similar after 1 year  

PubMed Central

Background and purpose Promising results have been reported after volar locked plating of unstable dorsally displaced distal radius fractures. We investigated whether volar locked plating results in better patient-perceived, objective functional and radiographic outcomes compared to the less invasive external fixation. Patients and methods 63 patients under 70 years of age, with an unstable extra-articular or non-comminuted intra-articular dorsally displaced distal radius fracture, were randomized to volar locked plating (n = 33) or bridging external fixation. Patient-perceived outcome was assessed with the Disability of the Arm, Shoulder, and Hand (DASH) questionnaire and the Patient-Rated Wrist Evaluation (PRWE) questionnaire. Results At 3 and 6 months, the volar plate group had better DASH and PRWE scores but at 12 months the scores were similar. Objective function, measured as grip strength and range of movement, was superior in the volar plate group but the differences diminished and were small at 12 months. Axial length and volar tilt were retained slightly better in the volar plate group. Interpretation Volar plate fixation is more advantageous than external fixation, in the early rehabilitation period. PMID:21281262

2011-01-01

12

Polymer cable/grip-plate system with locking screws for stable fixation to promote healing of trochanteric osteotomies or fractures in revision total hip arthroplasty.  

PubMed

Multiple methods have been proposed to establish stable fixation to promote healing of trochanteric osteotomies or fractures in revision total hip arthroplasty (revTHA), from wiring techniques through cable-plate systems with or without supplemental locking screws. The purpose of this study is to report the clinical results of a single cable-plate system with locked screw fixation in revTHA. Between 2009 and 2012, 27 grip-plates (Supercable® System, Kinamed Inc., Camarillo, CA) were used in 26 patients in 27 revTHA procedures. Utilization was 12 1-hole (50 mm) grip-plates, 10 2-hole (135 mm) grip-plates, four 4-hole (190 mm) grip-plates, and one 6-hole (245 mm) grip-plate. There were 14 women and 12 men. Age averaged 63.2 years and BMI averaged 29.4 kg/m2. At average 2.5 year follow-up, grip-plate fixation was considered successful in 22 hips (81%) with five failures. Three failures consisted of 50 mm/short grip-plates used in one trochanteric slide, and two intraoperative trochanteric fractures during revTHA. The two additional failures were related to pre-revision trochanteric avulsion from bony necrosis of the proximal femur. An additional three grip-plates were removed electively for soft-tissue irritation and pain but with successful fixation and bony healing. Thus 70% of hips were free of reoperation related to the grip-plate. All other hips had successful fixation and the grip-plate was not symptomatic. In this study, the cable-grip system and isoelastic Supercables provided reliable fixation for adequate healing of difficult ETO and trochanteric fractures with an 81% rate of mechanical success with radiographic and clinical healing observed. PMID:25398403

Berend, Keith R; Willen, Jacob L; Morris, Michael J; Adams, Joanne B; Lombardi, Adolph V

2014-11-01

13

Biomechanical comparison of dynamic condylar screw and locking compression plate fixation in unstable distal femoral fractures: An in vitro study  

PubMed Central

Background: Distal femur fractures are difficult to manage and the selection of implant for internal fixation remains controversial. The objective of this study is to establish the relative strength of fixation of a distal femoral locking plate (DFLP) compared with the dynamic condylar screw (DCS) in the distal femur fractures. Materials and Methods: Study was conducted on 16 freshly harvested cadaveric distal femoral specimens, eight implanted with DCS and other eight with DFLP. The construct was made unstable by removing a standard sized medial wedge of 1 cm base (gap-osteotomy) beginning 6 cm proximal to the lateral joint line in distal metaphyseal region with the loss of medial buttress. Fatigue test was conducted under load control mode at the frequency of I Hz. Specimens were subjected to cyclic loading of 2 kN, under observation for 50,000 cycles or until failure/cutout, which ever occurred earlier. Results: In DFLP group, there was no implant failure and the average number of cycles sustained was 50,000. Six out of eight specimens completed 50,000 cycles and two failed in DCS group. The average number of cycles sustained by DCS was 46150. Though the bone quality as assessed by dual energy X-ray absorptiometry DEXA was comparable in both DFLP and DCS group (P = 0.06), none failed in DFLP group and subsidence was 1.02 ± 0.34 mm (range: 0.60-1.32 mm), which was significantly 43% lower (P = 0.006) than subsidence in DCS group (1.82 ± 0.58; range: 1.20-3.08 mm). The average stiffness of DCS group was 52.8 ± 4.2 N/mm, which was significantly lower than average stiffness of locked condylar plate group (71.2 ± 5.1 N/mm) (P = 0.02). Conclusions: DFLP fixation of the distal femur fractures resulted in stronger construct than the DCS fixation in both cyclic loading and ultimate strength in biomechanical testing of a simulated A3 distal femur fracture. PMID:24379469

Singh, Ashutosh Kumar; Rastogi, Amit; Singh, Vakil

2013-01-01

14

Characteristics of two different locking compression plates in the volar fixation of complex articular distal radius fractures  

PubMed Central

Objectives To investigate the differences of open reduction and internal fixation (ORIF) of complex AO Type C distal radius fractures between two different models of a single implant type. Methods A total of 136 patients who received either a 2.4 mm (n = 61) or 3.5 mm (n = 75) distal radius locking compression plate (LCP DR) using a volar approach were followed over two years. The main outcome measurements included motion, grip strength, pain, and the scores of Gartland and Werley, the Short-Form 36 (SF-36) and the Disabilities of the Arm, Shoulder, and Hand (DASH). Differences between the treatment groups were evaluated using regression analysis and the likelihood ratio test with significance based on the Bonferroni corrected p-value of < 0.003. Results The groups were similar with respect to baseline and injury characteristics as well as general surgical details. The risk of experiencing a complication after ORIF with a LCP DR 2.4 mm was 18% (n = 11) compared with 11% (n = 8) after receiving a LCP DR 3.5 mm (p = 0.45). Wrist function was also similar between the cohorts based on the mean ranges of movement (all p > 0.052) and grip strength measurements relative to the contralateral healthy side (p = 0.583). In addition, DASH and SF-36 component scores as well as pain were not significantly different between the treatment groups throughout the two-year period (all p ? 0.005). No patient from either treatment group had a step-off > 2 mm. Conclusions Differences in plate design do not influence the overall final outcome of fracture fixation using LCP. PMID:23610680

von Recum, J.; Matschke, S.; Jupiter, J. B.; Ring, D.; Souer, J-S.; Huber, M.; Audigé, L.

2012-01-01

15

Distal tibia fractures: locked or non-locked plating?  

PubMed Central

Background and purpose Although plating is considered to be the treatment of choice in distal tibia fractures, controversies abound regarding the type of plating for optimal fixation. We conducted a systematic review to evaluate and compare the outcomes of locked plating and non-locked plating in treatment of distal tibia fractures. Patients and methods A systematic review was conducted using PubMed to identify articles on the outcomes of plating in distal tibia fractures that were published up to June 2012. We included English language articles involving a minimum of 10 adult cases with acute fractures treated using single-plate, minimally invasive techniques. Study-level binomial regression on the pooled data was conducted to determine the effect of locking status on different outcomes, adjusted for age, sex, and other independent variables. Results 27 studies met the inclusion criteria and were included in the final analysis of 764 cases (499 locking, 265 non-locking). Based on descriptive analysis only, delayed union was reported in 6% of cases with locked plating and in 4% of cases with non-locked plating. Non-union was reported in 2% of cases with locked plating and 3% of cases with non-locked plating. Comparing locked and non-locked plating, the odds ratio (OR) for reoperation was 0.13 (95% CI: 0.03–0.57) and for malalignment it was 0.10 (95% CI: 0.02–0.42). Both values were statistically significant. Interpretation This study showed that locked plating reduces the odds of reoperation and malalignment after treatment for acute distal tibia fracture. Future studies should accurately assess causality and the clinical and economic impact of these findings. PMID:24758325

Khalsa, Amrit S; Toossi, Nader; Tabb, Loni P; Amin, Nirav H; Donohue, Kenneth W; Cerynik, Douglas L

2014-01-01

16

Stainless steel versus titanium volar multi-axial locking plates for fixation of distal radius fractures: a randomised clinical trial  

PubMed Central

Background Distal radius fractures are among the most common fractures seen in the hospital emergency department. Of these, over 40% are considered unstable and require some form of fixation. In recent years with the advent of low profile plating, open reduction and internal fixation (ORIF) using volar plates has become the surgical treatment of choice in many hospitals. However, it is currently unknown which plating system has the lowest complication rate and/or superior clinical and radiological outcomes following surgery. Few studies have compared different types of plates, which may have various features, different plate and screw designs or may be manufactured from different materials (for example, stainless steel or titanium). This study will specifically investigate and compare the clinical and radiological outcomes and complication rates of two commonly used volar plating systems for fixation of distal radius fractures: one made from stainless steel (Trimed™ Volar Plate, Trimed™, California, USA) and the other made from titanium (Medartis® Aptus Volar Plate, Medartis®, Basel, Switzerland). The primary aim of this study is to determine if there is a difference on the Patient Reported Wrist Evaluation six months following ORIF using a volar plate for adult patients with a distal radius fracture. Methods/Design This study will implement a randomized prospective clinical trial study design evaluating the outcomes of two different types of volar plates: one plate manufactured from stainless steel (Trimed™ Volar Plate) and one plate manufactured from titanium (Medartis® Aptus Volar Plate). The surgery will be performed at a major trauma hospital in Brisbane, Australia. Outcome measures including function, adverse events, range of movement, strength, disability, radiological findings and health-related quality of life will be collected at 6 weeks, 3, 6, 12 and 24 months following surgery. A parallel economic analysis will also be performed. This randomized clinical trial is due to deliver results in December 2016. Discussion Results from this trial will contribute to the evidence on operative management of distal radius fractures and plate material type. Trial registration ACTRN12612000969864 PMID:24612524

2014-01-01

17

An in-vitro biomechanical comparison of the Orosco and AO locking plates for anterior cervical spine fixation.  

PubMed

The Orosco anterior cervical spine plate (H-plate) and the Morscher AO cervical locking plate (CSLP) were studied to determine their comparative in vitro mechanical properties in flexion. Human cadaver cervical spines were tested nondestructively in flexion as intact, destabilized, and stabilized specimens with both implants. Stabilized specimens were also subjected to a large angular displacement in an attempt to induce implant failure. Differences between intact, destabilized, and stabilized specimens were significant for both the CSLP and H-plate groups in flexion testing (p < 0.05). Large angular displacement testing resulted in plate/screw displacement with the H-plate but not with the CSLP. Small angular displacements in flexion was tolerated well by both implants, but only the CSLP maintained stability with large angular displacements. PMID:7670213

Smith, S A; Lindsey, R W; Doherty, B J; Alexander, J; Dickson, J H

1995-06-01

18

Arthroscopic-assisted locking compression plate clavicular hook fixation for unstable fractures of the lateral end of the clavicle: a prospective study.  

PubMed

The aim of this prospective study was to assess the clinical outcomes of an unstable fracture of the lateral end of the clavicle treated with an arthroscopic-assisted locking compressive plate (LCP) clavicular hook plate. Twenty-three patients underwent arthroscopic assisted LCP clavicular hook plate fixation for these fractures. All patients achieved clinical and radiological union over a mean of 4.2 months (range, 3.4-5 months). Four patients (17%) showed some degree of acromial osteolysis. Three patients (13%) showed radiological signs of arthrosis of the acromioclavicular joint. In one patient, a second fracture (stress) was observed between the medial two screws of the plate without an additional injury. Five patients (22%) showed subacromial bursitis on dynamic ultrasonography. The mean Constant and Murley score was 91 points (range, 81-98). The average level of pain in the shoulder at rest and on abduction was 1 (range, 0-2) and 2.4 (range, 0-4), respectively. Based on our experience, arthroscopic-assisted LCP hook plate fixation for the treatment of unstable fractures of the lateral end of the clavicle is not without complications. However, it is an acceptable alternative method that is easy to apply with good results. Furthermore, it prevents rotator cuff impingement, allows early mobilisation and maintains the acromioclavicular joint biomechanics. PMID:19998033

Lee, Kwang Won; Lee, Sang Ki; Kim, Kap Jung; Kim, Yong In; Kwon, Won Cho; Choy, Won Sik

2010-08-01

19

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

PubMed Central

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:25590989

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

2015-01-01

20

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

PubMed

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:25590989

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

2015-01-01

21

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

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 results in 36 patients per group. Discussion Results from this study protocol will improve the current evidence regarding to the surgical treatment these fractures. Trial registration ISCRTN09599740 PMID:24597699

2014-01-01

22

Endosteal Strut Augment Reduces Complications Associated With Proximal Humeral Locking Plates  

Microsoft Academic Search

Background  Locking-plate technology has renewed interest in plate fixation for treating proximal humerus fractures. Complications associated\\u000a with these devices, including loss of reduction, screw cutout, and intra-articular penetration, are frequent. Establishing\\u000a a second column of support may reduce complications and improve clinical outcome scores.\\u000a \\u000a \\u000a \\u000a \\u000a Questions\\/purposes  We asked whether addition of an endosteal cortical allograft strut, used as an augment to locking-plate fixation

Andrew S. Neviaser; Carolyn M. Hettrich; Brandon S. Beamer; Joshua S. Dines; Dean G. Lorich

23

Closed reduction and fixation of locked symphysis pubis using tubular external fixator: a case report.  

PubMed

Locked symphysis pubis is a kind of pelvic injury in which one pubic bone is jammed in the back of the other or opposite the obturator foramen following lateral compression forces. In this article, we present a 31-year-old female case of locked symphysis pubis which was treated by closed reduction using tubular external fixator. We believe that tubular external fixators are useful devices to perform closed reduction maneuvers for locked pelvic injuries and also help to reduce the need for open reduction and internal implant usage. PMID:23692202

Hal?c?, Mehmet; Karaman, ?brahim; Kafadar, ?brahim Halil; Argün, Ali Saltuk

2013-01-01

24

Biomechanical analysis of bicortical versus unicortical locked plating of mid-clavicular fractures  

Microsoft Academic Search

Objectives  Operative fixation of displaced mid-shaft clavicle fractures has been shown to improve the functional outcomes and decrease\\u000a the likelihood of non-union; however, little is known about the need for locking screws versus traditional screws. We, therefore,\\u000a evaluated the strength of unicortical locked plating versus traditional bicortical non-locking fixation methods.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Ten matched pairs of fresh, frozen cadaver clavicle specimens were obliquely

Daniel Hamman; Derek Lindsey; Jason Dragoo

2011-01-01

25

Prospects of implant with locking plate in fixation of subtrochanteric fracture: experimental demonstration of its potential benefits on synthetic femur model with supportive hierarchical nonlinear hyperelastic finite element analysis  

PubMed Central

Background Effective fixation of fracture requires careful selection of a suitable implant to provide stability and durability. Implant with a feature of locking plate (LP) has been used widely for treating distal fractures in femur because of its favourable clinical outcome, but its potential in fixing proximal fractures in the subtrochancteric region has yet to be explored. Therefore, this comparative study was undertaken to demonstrate the merits of the LP implant in treating the subtrochancteric fracture by comparing its performance limits against those obtained with the more traditional implants; angle blade plate (ABP) and dynamic condylar screw plate (DCSP). Materials and Methods Nine standard composite femurs were acquired, divided into three groups and fixed with LP (n?=?3), ABP (n?=?3) and DCSP (n?=?3). The fracture was modeled by a 20?mm gap created at the subtrochanteric region to experimentally study the biomechanical response of each implant under both static and dynamic axial loading paradigms. To confirm the experimental findings and to understand the critical interactions at the boundaries, the synthetic femur/implant systems were numerically analyzed by constructing hierarchical finite element models with nonlinear hyperelastic properties. The predictions from the analyses were then compared against the experimental measurements to demonstrate the validity of each numeric model, and to characterize the internal load distribution in the femur and load bearing properties of each implant. Results The average measurements indicated that the constructs with ABP, DCPS and LP respectively had overall stiffness values of 70.9, 110.2 and 131.4?N/mm, and exhibited reversible deformations of 12.4, 4.9 and 4.1?mm when the applied dynamic load was 400?N and plastic deformations of 11.3, 2.4 and 1.4?mm when the load was 1000?N. The corresponding peak cyclic loads to failure were 1100, 1167 and 1600?N. The errors between the displacements measured experimentally or predicted by the nonlinear hierarchical hyperelastic model were less than 18?%. In the implanted femur heads, the principal stresses were spatially heterogeneous for ABP and DCSP but more homogenous for LP, meaning LP had lower stress concentrations. Conclusion When fixed with the LP implant, the synthetic femur model of the subtrochancteric fracture consistently exceeds in the key biomechanical measures of stability and durability. These capabilities suggest increased resistance to fatigue and failure, which are highly desirable features expected of functional implants and hence make the LP implant potentially a viable alternative to the conventional ABP or DCSP in the treatment of subtrochancteric femur fractures for the betterment of clinical outcome. PMID:22545650

2012-01-01

26

Medial Column Arthrodesis Using an Anatomic Distal Fibular Locking Plate.  

PubMed

The medial column fusion is performed for a multitude of etiologies, including peritalar subluxation deformity, Charcot arthropathy, trauma, post-traumatic degenerative joint disease, and rheumatoid arthritis. Various surgical techniques have been described for medial column arthrodesis. We describe a new fixation method using an anatomic distal fibular locking plate for medial column arthrodesis. This technique provides a rigid construct in compromised or at risk bone. After a review of the surgical technique, we outline 2 case examples of patients with peritalar subluxation and Charcot arthropathy. PMID:24998041

Nasser, Ellianne M; LaPorta, Guido A; Trott, Kasandra

2014-07-01

27

A locking contoured plate for distal fibular fractures: mechanical evaluation in an osteoporotic bone model using screws of different length.  

PubMed

Osteoporotic bone with poor mechanical capacity provides limited stability after fixation of ankle fractures. Stabilization with an implant providing increased fixation strength in osteoporotic bone could reduce failure rates of fixation and allow a more functional treatment. The purpose of this study was to evaluate a locking contoured plate for fixation of distal fibular fractures in comparison with a conventional contoured plate in an osteoporotic bone model. Eighty cylinders of osteoporotic bone surrogates were fixed with the two plates. We performed torque-to-failure and cyclic testing experiments using screws of different length with a Zwick/Roell testing machine. The locking system showed higher torque-to-failure and maximum torque levels as compared with the conventional plate in torque-to-failure experiments and torsional cyclic testing. The locking contoured plate provides improved fixation strength in the osteoporotic bone model. The locking system may be appropriate for fixation of distal fibular fractures, especially in osteoporotic bone with poor mechanical capacity. PMID:23676259

Zahn, Robert K; Jakubietz, Michael; Frey, Sönke; Doht, Stefanie; Sauer, Alexander; Meffert, Rainer H

2014-02-01

28

Plate on Plate Technique of Minimally Invasive Percutaneous Plate Osteosynthesis in Distal Tibial Fractures, an Easy and Inexpensive Method of Fracture Fixation  

PubMed Central

Background: Plate on plate technique can lessen operative time and patient morbidity. Objectives: This study aimed to evaluate the outcomes of minimally invasive percutaneous plate osteosynthesis (MIPPO) using plate on plate technique of locking plate fixation for closed fractures of distal tibia in a prospective study. Patients and Methods: Twenty-five patients with distal tibial fractures were treated by MIPPO using locking plate by plate on plate technique. Preoperative variables including age of patient, mode of trauma, type of fracture and soft tissue status were recorded for each patient. Perioperative variables included surgical time and radiation exposure. Postoperative variables included wound status, time to union, return to activity and the American orthopaedic foot and ankle score (AOFAS). Results: All the fractures had united at one year. The average time to union was 16.8 weeks. There were two cases of superficial infection and two cases of deep infection, which required removal of hardware after the fracture was united. The average AO foot and ankle score was 83.6 in our study population. Conclusions: MIPPO using locking plate by plate on plate technique was a safe, effective, inexpensive and easily reproducible method for the treatment of distal tibial fractures in properly selected patients, which minimized operative time and soft tissue morbidity. PMID:25599064

Muzaffar, Nasir; Bhat, Rafiq; Yasin, Mohammad

2014-01-01

29

Minimally invasive metatarsal fracture repair with locking plates in a guanaco (Lama guanicoe).  

PubMed

An open grade I transverse diaphyseal fracture of the metatarsal bone in a 5-yr-old female guanaco (Lama guanicoe) was successfully stabilized with a locking plate system, which is a minimally invasive approach. A conical coupling screw-plate locking system with 3.0-mm-thick plates and 3.5-mm locking head screws was applied, after closed and indirect reduction of the bone segments, with an orthogonal configuration of the plates. The implants were protected postoperatively with a splinted bandage. The fracture healed without complications, the limb function was successfully recovered, and no major complications were observed at the 2-yr follow-up. The surgical procedure was carried out with biologic internal fixation supports and an adequate functional union within a time period similar to that reported for this species following other fracture fixation methods. This case highlights the potential benefit of combining minimally invasive plate osteosynthesis and plate-locking systems for fracture repair in camelids. PMID:25632682

Bertuglia, Andrea; Piga, Sara; Bullone, Michela; Piras, Lisa; von Degerfeld, Mitzy Mauthe

2014-12-01

30

Custom-made locked plating for acetabular fracture: a pilot study in 24 consecutive cases.  

PubMed

Clinical implementation of site-specific locking plates for acetabular fracture remains untested. Custom-made locking plates were manufactured using computer-aided design and computer-aided manufacture techniques for acetabular fractures to test this procedure. The 3-dimensional images constructed from computed tomography data of pelvises in patients with acetabular fractures were used for preoperative planning and to design the plates. Data for each plate were input into software for programming, and the generated code was transferred into a computerized numerical control digital milling machine for manufacturing. These plates were clinically implemented, and the implementation parameters, reduction quality, and Postel Merle d'Aubigné score were evaluated. Forty-nine custom-made locking plates were manufactured for 24 unilateral acetabular fractures. The manufacturing process for the plates averaged 6.9±2.2 days. Processing the plates delayed operations by 2.6±1.3 days in one-third of the cases. Plate contouring was avoided in 48 plates. The plates had anatomical shapes, excellently matching reduced bone surface. The screws locked with the obtained plates avoided intra-articular penetration and provided secure fixation that allowed early out-of-bed rehabilitation. No indications of implant failures or observations of screw back-outs were observed during follow-up. The clinical application of such plates is associated with the avoidance of plate contouring, low risk of intra-articular penetration, early out-of-bed rehabilitation, and a low rate of implant failure. Implementing such plates in clinical practice is worthy of further investigation, with a focus on selecting patient population and minimizing the time required for and cost of plate manufacturing. PMID:24992064

Xu, Meng; Zhang, Li-Hai; Zhang, Ying-Ze; Zhang, Li-Cheng; He, Chun-Qing; Wang, Yan; Tang, Pei-Fu

2014-07-01

31

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

PubMed Central

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

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

2014-01-01

32

Construction and Biomechanical Properties of PolyAxial Self-Locking Anatomical Plate Based on the Geometry of Distal Tibia  

PubMed Central

In order to provide scientific and empirical evidence for the clinical application of the polyaxial self-locking anatomical plate, 80 human tibias from healthy adults were scanned by spiral CT and their three-dimensional images were reconstructed using the surface shaded display (SSD) method. Firstly, based on the geometric data of distal tibia, a polyaxial self-locking anatomical plate for distal tibia was designed and constructed. Biomechanical tests were then performed by applying axial loading, 4-point bending, and axial torsion loading on the fracture fixation models of fresh cadaver tibias. Our results showed that variation in twisting angles of lateral tibia surface was found in various segments of the distal tibia. The polyaxial self-locking anatomical plate was constructed based on the geometry of the distal tibia. Compared to the conventional anatomical locking plate, the polyaxial self-locking anatomical plate of the distal tibia provides a better fit to the geometry of the distal tibia of the domestic population, and the insertion angle of locking screws can be regulated up to 30°. Collectively, this study assesses the geometry of the distal tibia and provides variable locking screw trajectory to improve screw-plate stability through the design of a polyaxial self-locking anatomical plate. PMID:25025051

Liang, Weiguo; Ye, Weixiong; Ye, Dongping; Zhou, Ziqiang; Chen, Zhiguang; Li, Aiguo; Xie, Zong-Han; Zhang, Lihai; Xu, Jiake

2014-01-01

33

Adult proximal humerus locking plate for the treatment of a pediatric subtrochanteric femoral nonunion: a case report.  

PubMed

Nonunions of pediatric subtrochanteric femur fractures are exceedingly rare and have to date not been reported in the literature. We present the case of an 11-year-old boy who developed such a nonunion after open reduction internal fixation using a pediatric locked proximal femur plate. Using an adult proximal humerus locking plate, adequate proximal fixation of the nonunion was obtained. Furthermore, previously placed distal screw holes were safely bridged and the biomechanical environment around the nonunion site improved. Uneventful healing was possible with the use of adjuvant bone grafting. No short- or midterm complications occurred. Although other implants can certainly be adapted to a use different than that of its original design, the present case suggests that adult proximal humerus locking plates may be a safe option for revision surgery of the proximal pediatric femur. PMID:21577158

Cortes, Luis E; Triana, Miguel; Vallejo, Francisco; Slongo, Theddy F; Streubel, Philipp N

2011-07-01

34

Treatment of femoral subtrochanteric fractures with proximal lateral femur locking plates  

PubMed Central

OBJECTIVE: To study the outcome of subtrochanteric hip fractures treated with proximal lateral femur locking plate. METHOD: We retrospectively reviewed the clinical results of 48 cases of femoral subtrochanteric fractures treated with proximal lateral femur locking plates from January 2008 to May 2010. The progress of fracture healing, as well as the occurrence of complications, was recorded. The function of the hip joint was evaluated by the Harris social index and the Parker and Palmer mobility score one year after the operation. RESULT: 45 patients were followed up until fracture union or a revision surgery. Among the 45 patients, 43 patients obtained fracture union without further intervention. Thirty-eight fractures healed with no loss of position at 1-year follow-up. There were no cases of hip screw cutting through the femoral head. The mean score of the Harris social index was 86.5±9.8 (73~95). The mean Parker and Palmer mobility score was 7.4±2.1 (3~9). CONCLUSION: The proximal lateral femur locking plate is the kind of stable and effective internal fixation for treating subtrochanteric hip fractures which has the advantage of stable fixation especially for the lateral femoral wall fracture. Level of Evidence IV, Case Series. PMID:24453626

Hu, Sun-jun; Zhang, Shi-min; Yu, Guang-rong

2012-01-01

35

Complication with Removal of a Lumbar Spinal Locking Plate  

PubMed Central

Introduction. The use of locking plate technology for anterior lumbar spinal fusion has increased stability of the vertebral fusion mass over traditional nonconstrained screw and plate systems. This case report outlines a complication due to the use of this construct. Case. A patient with a history of L2 corpectomy and anterior spinal fusion presented with discitis at the L4/5 level and underwent an anterior lumbar interbody fusion (ALIF) supplemented with a locking plate placed anterolaterally for stability. Fifteen months after the ALIF procedure, he returned with a hardware infection. He underwent debridement of the infection site and removal of hardware. Results. Once hardware was exposed, removal of the locking plate screws was only successful in one out of four screws using a reverse thread screw removal device. Three of the reverse thread screw removal devices broke in attempt to remove the subsequent screws. A metal cutting drill was then used to break hoop stresses associated with the locking device and the plate was removed. Conclusion. Anterior locking plates add significant stability to an anterior spinal fusion mass. However, removal of this hardware can be complicated by the inherent properties of the design with significant risk of major vascular injury. PMID:25838956

Crawford, Brooke; Lenarz, Christopher; Watson, J. Tracy; Alander, Dirk

2015-01-01

36

Complication with removal of a lumbar spinal locking plate.  

PubMed

Introduction. The use of locking plate technology for anterior lumbar spinal fusion has increased stability of the vertebral fusion mass over traditional nonconstrained screw and plate systems. This case report outlines a complication due to the use of this construct. Case. A patient with a history of L2 corpectomy and anterior spinal fusion presented with discitis at the L4/5 level and underwent an anterior lumbar interbody fusion (ALIF) supplemented with a locking plate placed anterolaterally for stability. Fifteen months after the ALIF procedure, he returned with a hardware infection. He underwent debridement of the infection site and removal of hardware. Results. Once hardware was exposed, removal of the locking plate screws was only successful in one out of four screws using a reverse thread screw removal device. Three of the reverse thread screw removal devices broke in attempt to remove the subsequent screws. A metal cutting drill was then used to break hoop stresses associated with the locking device and the plate was removed. Conclusion. Anterior locking plates add significant stability to an anterior spinal fusion mass. However, removal of this hardware can be complicated by the inherent properties of the design with significant risk of major vascular injury. PMID:25838956

Crawford, Brooke; Lenarz, Christopher; Watson, J Tracy; Alander, Dirk

2015-01-01

37

Additive fiber-cerclages in proximal humeral fractures stabilized by locking plates  

PubMed Central

Background and purpose The effect of additive fiber-cerclages in proximal humeral fractures stabilized by locking plates on fracture stabilization and rotator cuff function is unclear. Here it was assessed in a human cadaver study. Methods 24 paired human shoulder specimens were harvested from median 77-year-old (range 66–85) female donors. An unstable 3-part fracture model with an intact rotator cuff was developed. 1 specimen of each pair received an additive fiber-cerclage of the rotator cuff after plate fixation, and the other one received a plate fixation without an additive fiber-cerclage. Force-controlled hydraulic cylinders were used to simulate physiological rotator cuff tension, while a robot-assisted shoulder simulator performed 4 relevant cases of load: (1) axial loading at 0°, (2) glenohumeral abduction at 60°, (3) internal rotation at 0° abduction, and (4) external rotation at 0° abduction, and imitated hanging arm weight during loading without affecting joint kinematics. A 3-dimensional real-time interfragmentary motion analysis was done in fracture gaps between the greater tuberosity and the head, as well as subcapital. The capacity of the rotator cuff to strain was analyzed with an optical system. Results Interfragmentary motion was similar between the groups with and without fiber-cerclages, in both fracture gaps and in any of the cases of load. Cerclages did not impair the capacity of the rotator cuff to strain. Interpretation Provided that unstable 3-part fractures are reduced and stabilized anatomically by a locking plate, additive fiber-cerclages do not reduce interfragmentary motion. Additive fiber-cerclages may be necessary in locking plate osteosyntheses of multiple-fractured greater tuberosities or lesser tuberosity fractures that cannot be fixed sufficiently by the plate. PMID:19562564

Hurschler, Christof; Rech, Louise; Vosshenrich, Rolf; Lill, Helmut

2009-01-01

38

LCP distal ulna hook plate as alternative fixation for fifth metatarsal base fracture.  

PubMed

Intramedullary screw fixation is the most common treatment for fifth metatarsal base fractures. Screw application does not achieve accurate reduction in fracture with small fragments, osteoporotic bone, or Lawrence zone 1 fractures, however. On the basis of similar anatomical architectures between the distal ulna and the fifth metatarsal base, the purpose of this study was to assess the results of a locking compression plate (LCP) distal ulna hook plate in stabilizing displaced zone 1 or 2 fifth metatarsal base fractures. Nineteen patients with Lawrence zone 1 (n = 12) or 2 (n = 7) fractures of the fifth metatarsal base were treated surgically with an LCP distal ulna hook plate. The patients were evaluated clinically and radiographically, and functional outcomes were graded by using the American Orthopaedic Foot and Ankle Society (AOFAS) midfoot scoring system. Radiographic bony union was obtained in all patients, at an average of 7.4 weeks. The mean AOFAS midfoot score improved from 26 (range, 0-45) preoperatively to 94 (range, 72-100) points at the final follow-up. There were three patients with post-traumatic cubometatarsal arthrosis and one patient with sural nerve neuropraxia. In our experience, the distal ulna hook plate achieves a high rate of bony consolidation and anatomically suitable fixation in zone 1 or 2 fifth metatarsal base fractures. We also suggest that the LCP distal ulna hook plate should be considered as an alternative treatment in multifragmentary, osteoporotic, and tuberosity avulsion (zone 1) fifth metatarsal base fractures. PMID:23412193

Lee, Sang Ki; Park, Ju Sang; Choy, Won Sik

2013-08-01

39

A Novel Fixation System for Acetabular Quadrilateral Plate Fracture: A Comparative Biomechanical Study  

PubMed Central

This study aims to assess the biomechanical properties of a novel fixation system (named AFRIF) and to compare it with other five different fixation techniques for quadrilateral plate fractures. This in vitro biomechanical experiment has shown that the multidirectional titanium fixation (MTF) and pelvic brim long screws fixation (PBSF) provided the strongest fixation for quadrilateral plate fracture; the better biomechanical performance of the AFRIF compared with the T-shaped plate fixation (TPF), L-shaped plate fixation (LPF), and H-shaped plate fixation (HPF); AFRIF gives reasonable stability of treatment for quadrilateral plate fracture and may offer a better solution for comminuted quadrilateral plate fractures or free floating medial wall fracture and be reliable in preventing protrusion of femoral head.

Zha, Guo-Chun; Sun, Jun-Ying; Dong, Sheng-Jie; Zhang, Wen; Luo, Zong-Ping

2015-01-01

40

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

PubMed Central

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

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

2013-01-01

41

Improving stability of locking compression plates through a design modification: a computational investigation.  

PubMed

Femoral shaft fractures are common in both the young and elderly due to high-impact trauma and low-impact trauma, respectively. Its treatment by indirect reduction through use of locking compression plates (LCPs) has been on the rise. The LCP possess several advantages in fracture fixation, combining angular stability through use of locking screws with misalignment correction and fracture reduction onto the plate through use of conventional screws. However, there have been cases of plate breakage and fracture non-unions to warrant a study to improve its stability. A design modification is suggested for mid-diaphyseal fractures, whereby unused screw holes are removed. The structural stability of the modified and commercially available LCP is computationally analyzed using finite element modelling and a comparison made in terms of mechanical performance across different fracture lengths. A critical fracture length for which the commercially available LCP is functional as a fixator for mid-diaphyseal fractures was established. The maximum von Mises' stress attained by the commercially available LCP rose to as high as 105 MPa, whereas for the modified LCP, it did not exceed 25 MPa. As expected, these stresses were also found at screw holes, nearest to the fracture site. Critical fracture length allows clinicians to quantitatively distinguish between mid-diaphyseal fractures that can or cannot be treated by the use of LCP fixation. It is also believed that the proposed design modification will substantially increase the fatigue life of the fixator, especially at screw holes nearest to the fracture region, where most fatigue fractures are known to occur and will consequently be functional for greater fracture lengths. PMID:23582021

Anitha, D; Das De, Shamal; Sun, Khong Kok; Doshi, Hitendra K; Lee, Taeyong

2015-01-01

42

Polyaxial locking and compression screws improve construct stiffness of acetabular cup fixation: a biomechanical study.  

PubMed

Bone ingrowth into uncemented acetabular components requires intimate cup-bone contact and rigid fixation, which can be difficult to achieve in revision hip arthroplasty. This study compares polyaxial compression locking screws with non-locked and cancellous screw constructs for acetabular cup fixation. An acetabular cup modified with screw holes to provide both compression and angular stability was implanted into a bone substitute. Coronal lever out, axial torsion and push-out tests were performed with an Instron testing machine, measuring load versus displacement. Polyaxial locking compression screws significantly improved construct stiffness compared with non-locked or cancellous screws. This increased construct stiffness will likely reduce interfacial micromotion. Further research is required to determine whether this will improve bone ingrowth in vivo and reduce cup failure. PMID:24360790

Milne, Lachlan P; Kop, Alan M; Kuster, Markus S

2014-05-01

43

A LOCKING-FREE LAMINATED COMPOSITE PLATE FINITE ELEMENT  

Microsoft Academic Search

A plate finite element which is locking-free is developed usi ng strain gradient notation for the analysis of laminated composites. The element is based on a first-order s hear deformation theory and on the equivalent lamina assumption. Strains and stresses can be calculated at diffe rent points through the laminate's thickness. The paraboli c nature of the transverse shear strain

Ivan Moura Belo

2005-01-01

44

Magnetically Operated Holding Plate And Ball-Lock Pin  

NASA Technical Reports Server (NTRS)

Magnetically operated holding plate and ball-locking-pin mechanism part of object attached to, or detached from second object. Mechanism includes tubular housing inserted in hole in second object. Plunger moves inside tube forcing balls to protrude from sides. Balls prevent tube from sliding out of second object. Simpler, less expensive than motorized latches; suitable for robotics applications.

Monford, Leo G., Jr.

1992-01-01

45

Titanium Plate Fixation for Sternal Dehiscence in Major Cardiac Surgery  

PubMed Central

Background Sternal dehiscence is one of the most troublesome complications following cardiac surgery. Treatment failure and consequent lethal outcomes are very common. The aim of this study was to evaluate titanium plate fixation as a treatment for sternal dehiscence following major cardiac surgery. Materials and Methods Between 2010 and 2012, 17 patients underwent sternal reconstruction using horizontal titanium plating for the treatment of post-cardiac-surgery sternal dehiscence. The plates were cut and shaped, and then were fixed to corresponding costal segments using 2-3 titanium screws per each side. Results The median age of our patients was 66 years (range, 50 to 78 years) and 9 were female. Indications for sternal reconstruction included aseptic sternal dehiscence in 3 patients and osteomyelitis in 14 patients including 6 patients who were diagnosed with mediastinitis. During the operation, sternal resection and autologous flap interposition were combined in 11 patients. One patient died due to sepsis. Two patients required additional soft tissue wound revisions. Another patient presented with a tuberculous wound infection which was resolved using anti-tuberculosis medications. The postoperative course was uncomplicated in the other 13 patients. Conclusion Titanium plate fixation that combines appropriate debridement and flap interposition is very effective for the treatment of sternal dehiscence following major cardiac surgery. PMID:24003409

Kim, Wan Kee; Kim, Gwan Sic; Jung, Sung-Ho; Choo, Suk Jung; Chung, Cheol Hyun; Lee, Jae Won

2013-01-01

46

Aramid-epoxy composite internal fixation plates: a pilot study.  

PubMed

Mechanical tests were conducted on an aramid-epoxy composite laminate in vitro and in vivo to determine its suitability for internal fixation plates. This material, fashioned into blank test coupons the size of the standard 4-hole AO-ASIF plates, had a tensile modulus of elasticity significantly lower than bone. In three-point bending, blank test coupons exhibited a low yield strength that would limit utility in significant load-bearing situations, but changes in the layer configuration of the composite could be expected to improve this characteristic. Under destructive loads, these specimens appeared to be less subject to catastrophic failure than carbon fibre composites. Using 4-hole test coupons fastened to a plastic tube simulating bone, four-point bending tests showed that strain-shielding was significantly reduced by aramid composite relative to carbon fibre composite or metal plates. Finally, in-vivo tests on canine femora demonstrated that aramid composite plates were well tolerated and caused less strain shielding during weightbearing, but significant differences in cortical atrophy and porosity beneath steel versus aramid plates were not apparent. Although the plates were relatively flexible, they could not be preformed during surgery like a metal plate. PMID:23916301

Cochran, G V; Palmieri, V R; Zickel, R E

1994-09-01

47

Outcomes of Pin and Plaster Versus Locking Plate in Distal Radius Intraarticular Fractures  

PubMed Central

Background Distal radius fractures are among the most prevalent fractures predictive of probable occurrence of other osteoporotic fractures. They are treated via a variety of methods, but the best treatment has not been defined yet. Objectives This study was performed to compare the results of open reduction and internal fixation with locking plates versus the pin and plaster method. Materials and Methods In this prospective study, 114 patients aged 40 to 60 years with Fernandez type III fracture referring to Imam-Reza and Mehr hospitals of Mashhad from 2009 to 2011, were selected randomly; after obtaining informed consent, they were treated with pin and plaster fixation (n = 57) or internal fixation with the volar locking plate (n = 57). They were compared at the one year follow up. Demographic features and standard radiographic indices were recorded and MAYO, DASH and SF - 36 tests were performed. Data was analyzed by SPSS software version 13, with descriptive indices, Mann-Whitney and Chi-square tests. Results SF-36 test demonstrated a better general health (P < 0.001), mental health (P = 0.006), physical functioning (P < 0.001), social functioning (P < 0.001) and energy/fatigue (P < 0.001) in LCP group. However, pain (P = 0.647) was not significantly different between the groups. Physical limitation (P < 0.001) and emotional limitation (P < 0.001) were greater in the pin and plaster group. Also, in the LCP group mean MAYO score (P < 0.001) was more than pin and plaster group. Mean DASH score was not different between the groups (P = 0.218). The rate of acceptable results of radiographic indices (P < 0.001), grip strength (P < 0.001) and range of motion in supination-pronation (P < 0.001) in LCP method were better than the pin and plaster method. Conclusions In treatment of intra-articular distal radius fractures in middle-aged patients internal fixation with locking plates may be prefered to pin and plaster as the treatment of choice. PMID:24350132

Bahari-Kashani, Mahmoud; Taraz-Jamshidy, Mohammad Hosein; Rahimi, Hassan; Ashraf, Hami; Mirkazemy, Masoud; Fatehi, Amirreza; Asadian, Mariam; Rezazade, Jafar

2013-01-01

48

Clinical outcomes of locked plating of distal femoral fractures in a retrospective cohort  

PubMed Central

Purpose Locked plating (LP) of distal femoral fractures has become very popular. Despite technique suggestions from anecdotal and some early reports, knowledge about risk factors for failure, nonunion (NU), and revision is limited. The purpose of this study was to analyze the complications and clinical outcomes of LP treatment for distal femoral fractures. Materials and methods From two trauma centers, 243 consecutive surgically treated distal femoral fractures (AO/OTA 33) were retrospectively identified. Of these, 111 fractures in 106 patients (53.8% female) underwent locked plate fixation. They had an average age of 54 years (range 18 to 95 years): 34.2% were obese, 18.9% were smokers, and 18.9% were diabetic. Open fractures were present in 40.5% with 79.5% Gustilo type III. Fixation constructs for plate length, working length, and screw concentration were delineated. Nonunion and/or infection, and implant failure were used as outcome complication variables. Outcome was based on surgical method and addressed according to Pritchett for reduction, range of motion, and pain. Results Eighty-three (74.8%) of the fractures healed after the index procedure. Twenty (18.0%) of the patients developed a NU. Four of 20 (20%) resulted in a recalcitrant NU. Length of comminution did not correlate to NU (p?=?0.180). Closed injuries had a higher tendency to heal after the index procedure than open injuries (p?=?0.057). Closed and minimally open (Gustilo/Anderson types I and II) fractures healed at a significantly higher rate after the index procedure compared to type III open fractures (80.0% versus 61.3%, p?=?0.041). Eleven fractures (9.9%) developed hardware failure. Fewer nonunions were found in the submuscular group (10.7%) compared to open reduction (32.0%) (p?=?0.023). Fractures above total knee arthroplasties had a significantly greater rate of failed hardware (p?=?0.040) and worse clinical outcome according to Pritchett (p?=?0.040). Loss of fixation was related to pain (F?=?3.19, p?=?0.046) and a tendency to worse outcome (F?=?2.43, p?=?0.071). No relationship was found between nonunion and working length. Conclusion Despite modern fixation techniques, distal femoral fractures often result in persistent disability and worse clinical outcomes. Soft tissue management seems to be important. Submuscular plate insertion reduced the nonunion rate. Preexisting total knee arthroplasty increased the risk of hardware failure. Further studies determining factors that improve outcome are warranted. PMID:24279475

2013-01-01

49

Design optimisation and experimental evaluation of dorsal double plating fixation for distal radius fracture.  

PubMed

This study determines the relative effects of changes in osteoporosis condition, plate/screw design factors (plate angle/length/width/thickness and screw diameter) and fixation methods (screw number and screw length) on the biomechanical response of dorsal double plating (DDP) fixation at a distal radius fracture to determine the optimal design and evaluate its biomechanical strength using the dynamic fatigue test. Eighteen CAD and finite element (FE) models corresponding to a Taguchi L18 array were constructed to perform numerical simulations to simulate the mechanical responses of a DDP fixed in a simply distal radius fracture bone. The Taguchi method was employed to determine the significance of each design factor in controlling bone/plate/screw stress and distal fragment displacement under axial (100 N), bending (1 N m) and torsion (1 N m) loads. Simulation results indicated that the order rank to determine the mechanical response was the plate thickness, plate width, screw diameter, and number of screws. Dorsal intermediate (L) plate with 60 mm length, 1.8 mm thickness, 6.0 mm width and 2.8 mm diameter, 20 mm length dual-thread locking screw can be found for optimisation. The DDP, including an L plate with 0°, 30° and 60° angles and a straight I plate, were made with Ti6Al4V to fix onto the sawbones with three corresponding radius fractures to perform the dynamic testing. The specimens were oscillated with loads between 10 N and 150 N at 5 Hz for 20,000 cycles. The average stiffness in 20,000 test cycles was 425.7 N/mm, 461.1 N/mm and 532.1N/mm for the 0°, 30° and 60° constructs, respectively. No difference in stiffness was found in the same angled constructs throughout the 20,000 cycles of testing (p > 0.05). Lack of gross construct failures during cyclic testing and reasonable stiffness corroborated that our new constructs tested to date seem stable enough to support restricted post-operative loads. PMID:23099020

Chen, Alvin Chao-Yu; Lin, Yu-Hao; Kuo, Hsien-Nan; Yu, Tsung-Chih; Sun, Ming-Tsung; Lin, Chun-Li

2013-04-01

50

Analysis and design of an adjustable bone plate for mandibular fracture fixation  

E-print Network

This thesis presents the design, analysis and testing of a bone plate for mandibular fracture fixation. Conventional bone plates are commonly used to set fractures of the mandible in a surgical setting. If proper alignment ...

Cervantes, Thomas Michael

2011-01-01

51

Design-optimization and material selection for a femoral-fracture fixation-plate implant  

E-print Network

functional requirements pertaining to attain the required level of fracture-femur fixation and longevityDesign-optimization and material selection for a femoral-fracture fixation-plate implant M and simulations Femoral-fracture fixed-plate implant Optimization a b s t r a c t The problem of size

Grujicic, Mica

52

Cerclage wire-plate composite for fixation of quadrilateral plate fractures of the acetabulum: a checkrein and pulley technique.  

PubMed

Acetabular fractures with complete or incomplete quadrilateral plate separation frequently present with central displacement of the femoral head. Failure of stable fixation of medial wall fractures leaves residual subluxation despite reduction of other fracture components. Several fixation techniques may be either technically demanding or insufficient for stable fixation in conditions of comminution, osteoporosis, or neglected injuries. The proposed wire-plate composite uses a reconstruction spring plate over the pelvic brim for medial wall buttressing. One hole on its true pelvic limb provides a pulley to deviate a cerclage wire or cable passed through the greater sciatic notch into the true pelvis. This enhances buttressing against medial protrusion. Application through anterior approaches is simple and fixation is reliable in difficult fractures without the risk of joint penetration because all quadrilateral plate buttressing implants remain extraosseous. PMID:20418739

Farid, Yasser R

2010-05-01

53

Biomechancis of biological fixation utilizing a plate with and without an intramedullary rod  

E-print Network

. Loading Frequency . C. Effects of a Fracture D. Fracture Treatment Methods . E. Purpose of Study BIOLOGY AND PRINCIPLES OF INTERNAL FIXATION A. Biology of Bone Healing 1. Secondary Bone Healing 2. Clinical Significance of Secondary Bone Healing . 3.... Primary Bone Healing . 4. Clinical Significance of Primary Bone Healing . . B. Vascular Supply . 1. Blood Supply to Normal Bone 2. Blood Supply to Healing Bone a. Intramedullary Fixation b. Bone Plating C. Internal Fixation Devices 1. Principles...

Nori, Meera

1994-01-01

54

Technical tips: dualplate fixation technique for comminuted proximal humerus fractures.  

PubMed

The authors report dualplate fixation technique for providing stable fixation in comminuted proximal humerus fractures. This technique has been used for proximal humerus fractures with metaphyseal comminution and provides excellent anatomical reduction and neck shaft angle (NSA). The recently locking plate is clinically more widely used due to its small size, low rigidity, high elasticity, and biomechanical properties such as fixed initial angle and rotational stability. However, in severely comminuted complex type proximal metaphyseal humerus fractures, the use of locking plate alone does not provide stable fixation, leading to complications such as varus collapse, anterior-posterior angulation, screw cutout, nonunion, malunion, and metal failure. Therefore, a more robust and enhanced fixation method, the dual plating technique using the locking compression plate (Proximal Humeral Internal Locking System and Variable Angle Locking Compression Plate) was developed. PMID:24813097

Choi, Sungwook; Kang, Hyunseong; Bang, Hyeongsig

2014-08-01

55

Volar Plate Fixation of Intra-Articular Distal Radius Fractures: A Retrospective Study  

PubMed Central

Background Intra-articular fractures of the distal radius represent a therapeutic challenge as compared with the unstable extra-articular fractures. With the recent development of specifically designed internal fixation materials for the distal radius, treatment of these fractures by fragment-specific implants using two or more incisions has been advocated. Purpose The purpose of this study was to investigate the efficacy of a fixed-angle locking plate applied through a single volar approach in maintaining the radiographic alignment of unstable intra-articular fractures as well as to report the clinical outcomes. We only excluded those with massive comminution, as is discussed in greater detail in the text. Patients and Methods This is a multicentered, retrospective study involving three hospitals situated in Spain, Switzerland, and the United States. In the period between January 2000 and March 2006, 97 patients with 101 intra-articular distal radius fractures, including 13 volarly displaced and 88 dorsally angulated fractures were analyzed. Over 80% were C2/C3 fractures, based on the AO classification. 16 open fractures were noted. Results With an average follow-up of 28 months (range 24-70 months), the range of movement of the wrist was very satisfactory, and the mean grip strength was 81% of the opposite wrist. The Disabilities of the Arm, Shoulder, and Hand (DASH) score was 8. The complications rate was < 5%, including loss of reduction in two patients. All fractures healed by 3 months postinjury. Conclusions Irrespective of the direction and amount of initial displacement, a great majority of intra-articular fractures of the distal radius can be managed with a fixed-angle volar plate through a single volar approach. Level IV retrospective case series PMID:24436824

Fok, Margaret W. M.; Klausmeyer, Melissa A.; Fernandez, Diego L.; Orbay, Jorge L.; Bergada, Alex Lluch

2013-01-01

56

Clinical Outcomes of Distal Femoral Fractures in the Geriatric Population Using Locking Plates With a Minimally Invasive Approach  

PubMed Central

Background: Fractures of the distal femur comprise 4% to 6% of all femoral fractures. Elderly patients are predisposed to low-energy fractures due to osteoporosis. Treatment of these fractures in the elderly group remains a challenge. Our hypothesis is that locking plates inserted with minimally invasive plate osteosynthesis (MIPO) techniques will produce better results compared to those inserted by open technique. The objective of this study is to evaluate the clinical outcomes of MIPO technique using locking plates in the elderly patients. Materials and Methods: A total of 24 elderly patients (mean age 73 years) with distal femur fractures treated using the MIPO technique (2007-2010) were reviewed retrospectively. Parameters analyzed included classification of fracture, time to fracture union, knee range of motion, functional knee score (Knee Society Score—Functional) at 6 months, and other significant complications. One patient was lost to follow-up. Results: In all, 88% of the fractures were extraarticular. The mean time to union was 13.48 (range: 8-28) weeks. Mean range of motion achieved at 6 months and beyond was 100° ranging from 0 to 30 (extension) to 90 to 140 (flexion). Functional knee scores at 6 months from fixation were satisfactory (mean score 88.8). There were no cases of implant failure, nonunion, and infection. In all, 6 (25%) patients developed deep vein thrombosis (DVT) in the early postoperative period, all of which were below the level of the knee joint. Conclusion: Locking plates inserted using MIPO techniques in elderly patients with distal femur fractures appear to be promising based on clinical outcome measurements. However, there was a high incidence of DVT noted. PMID:23936735

Doshi, Hitendra K.; Wenxian, Png; Burgula, Maitra Vaarun; Murphy, Diarmuid Paul

2013-01-01

57

Processing and evaluation of long fiber thermoplastic composite plates for internal fixation  

NASA Astrophysics Data System (ADS)

The metallic plates used in internal fracture fixation may have up to ten times the elastic modulus of normal bone tissue, causing stress shielding-induced osteopenia in healed bone that can lead to re-fracture after plate removal and prolonged and painful recovery. Thermoplastic polymer matrix composites reinforced with long carbon fiber are promising alternative materials for internal fixation plates because they may be produced with relative ease and be tailored to have specific mechanical properties, alleviating the stress shielding problem. Long carbon fiber-reinforced polyetheretherketone (LCF PEEK) plates were produced using the extrusion / compression molding process. Static flexural testing determined that LCF PEEK plates with rectangular cross-section had an average flexural modulus of 12 GPa, or 23% of the flexural modulus of a stainless steel plate. The LCF PEEK plates also experienced negligible (14.7%, 14.5%, and 16.7%) reductions in modulus after fatigue testing at applied moments of 2.5, 3.0, and 3.5 N•m, respectively, over 106 load cycles. Aging the plates in 0.9% NaCl solution for four and eight weeks caused 0.34% and 0.28% increases in plate mass, respectively. No significant decrease of flexural properties due to aging was detected. Differential scanning calorimetry (DSC) revealed the PEEK matrix of the plates to be 24.5% crystalline, which is lower than typical PEEK crystallinity values of 30-35%. Scanning electron microscopy (SEM) revealed three times as many fiber pullout areas in LCF PEEK fracture surfaces as in fracture surfaces of long carbon fiber-reinforced polyphenylenesulfide (LCF PPS), another plate material tested. DSC and SEM data suggest that improvements in processing conditions and fiber/matrix bonding, along with higher carbon fiber fractions, would enhance LCF PEEK plate performance. LCF PEEK remains a promising alternative to stainless steel for internal fixation plates.

Warren, Paul B.

58

Arthroscopic evaluation for omalgia patients undergoing the clavicular hook plate fixation of distal clavicle fractures  

PubMed Central

Background The aim of this study is to investigate the anatomic changes in the shoulder joints responsible for omalgia after the clavicular hook plate fixation under arthroscope. Methods Arthroscopic examination was carried out for 12 omalgia patients who underwent clavicular hook plate fixation due to distal clavicle fractures. Functional outcome of shoulder was measured by the Japanese Orthopaedic Association (JOA) score before and after the withdrawal of the fixation plate. Results The rotator cuff compression by the clavicular hook was arthroscopically observed in 11 of the 12 cases. The JOA scores of the shoulder were significantly improved at 1 month after the withdrawal of the fixation plate (pain, 28?±?2.4 vs. 15?±?5.2; function, 19.2?±?1.0 vs. 11.7?±?1.9; range of movements, 26.8?±?2.6 vs. 14.8?±?3.4) compared with before. Conclusions The impingement of the hook to the rotator cuff may be the main cause for the omalgia. The appropriate hook and plate that fit to the curve of the clavicle as well as the acromion are necessary to decrease the severity of omalgia. PMID:24917508

2014-01-01

59

Surgical treatment of calcaneal fractures of sanders type II and III by a minimally invasive technique using a locking plate.  

PubMed

The aim of the present study was to investigate the outcomes of surgical treatment of calcaneal fractures of Sanders type II and III using a minimally invasive technique and a locking plate. We reviewed 33 feet in 33 consecutive patients with Sanders type II and III calcaneal fractures who had undergone a minimally invasive technique using percutaneous reduction and locking plates. All operations were performed by the same surgeons. The postoperative evaluation included radiographs, determination of restoration of Böhler's angle and Gissane's angle, and administration of the American Orthopaedic Foot and Ankle Society ankle-hind foot scale, Maryland Foot Score, and visual analog scale of pain. The mean visual analog scale score was 1.6 ± 1.4 when radiographic fracture healing was observed. The median functional score of the 33 patients (33 feet) reached 82 (interquartile range 80 to 99) at the last follow-up evaluation according to the American Orthopaedic Foot and Ankle Society ankle-hind foot scale and 89 (interquartile range 80 to 99) according to Maryland Foot Score. All cases achieved restoration of a normal Böhler's angle and Gissane's angle. Postoperative superficial infections occurred in 2 patients, subtalar arthritis developed in 2, and no soft tissue necrosis was observed. For Sanders type II and III fractures of the calcaneus bone, treatment with a minimally invasive technique combining percutaneous reduction and locking plate fixation provided satisfactory clinical results, with a lower incidence of complications. However, longer term studies with a larger sample size and more randomized controlled trials are required to define the superiority of our minimally invasive technique compared with conventional surgical treatment of calcaneal fractures. PMID:25441282

Cao, Liehu; Weng, Weizong; Song, Shaojun; Mao, Ningfang; Li, Haihang; Cai, Yuanqi; Zhou, Qirong; Su, Jiacan

2015-01-01

60

Flexor tendon repair after rupture caused by volar plate fixation of the distal radius.  

PubMed

Volar plate fixation of unstable fractures of the distal radius is preferred by a majority of surgeons today. One known complication is the rupture of flexor tendons. The aim of this paper is to present flexor tendon ruptures after volar plate fixation analysing the clinical outcome after tendon surgery, aetiology, and methods of prevention. Seventeen consecutive ruptures in 14 patients were included. The incidence was 1.4%. Three patients declined tendon surgery. Eleven patients were treated with a free tendon graft. Only two patients showed excellent results regarding mobility in the thumb and/or fingers. Analysis of radiographs demonstrated sub-optimal placement of plate or screws in all cases. Rupture of a flexor tendon is a serious complication where the functional outcome after surgical reconstruction is uncertain. Early removal of the plate when the placement is sub-optimal or when local volar tenderness appears would probably prevent many ruptures. PMID:25162925

Rubensson, Carin C; Ydreborg, Karin; Boren, Linda; Karlander, Lars-Erik

2015-04-01

61

Two load sharing plates fixation in mandibular condylar fractures: biomechanical basis.  

PubMed

Mandibular condylar fractures have a high incidence but there is no consensus regarding the best choice of osteosynthesis. From a review of the literature, it is evident that the technique used most frequently for fixation is the positioning of a single plate despite complications concerning plate fracture or screw loosening have been reported by various authors. Different studies have highlighted that the stability of osteosynthesis is correlated with the mechanical strains occurring in the condylar region, generated by the muscles of mastication. The aim of our study was, through a mandibular finite element model (FEM), to confirm this correlation and to analyse the behaviour of single and double elements of union in the fixation of mandibular subcondylar fractures. We concluded that the use of two plates provides greater stability compared with the single plate, reducing the possibility of displacement of the condylar fragment. Therefore we recommend that this technique should be adopted whenever possible. PMID:19944616

Parascandolo, Salvatore; Spinzia, Alessia; Parascandolo, Stefano; Piombino, Pasquale; Califano, Luigi

2010-07-01

62

Dose distribution near thin titanium plate for skull fixation irradiated by a 4-MV photon beam  

PubMed Central

To investigate the effects of scattered radiation when a thin titanium plate (thickness, 0.05 cm) used for skull fixation in cerebral nerve surgery is irradiated by a 4-MV photon beam. We investigated the dose distribution of radiation inside a phantom that simulates a human head fitted with a thin titanium plate used for post-surgery skull fixation and compared the distribution data measured using detectors, obtained by Monte Carlo (MC) simulations, and calculated using a radiation treatment planning system (TPS). Simulations were shown to accurately represent measured values. The effects of scattered radiation produced by high-Z materials such as titanium are not sufficiently considered currently in TPS dose calculations. Our comparisons show that the dose distribution is affected by scattered radiation around a thin high-Z material. The depth dose is measured and calculated along the central beam axis inside a water phantom with thin titanium plates at various depths. The maximum relative differences between simulation and TPS results on the entrance and exit sides of the plate were 23.1% and – 12.7%, respectively. However, the depth doses do not change in regions deeper than the plate in water. Although titanium is a high-Z material, if the titanium plate used for skull fixation in cerebral nerve surgery is thin, there is a slight change in the dose distribution in regions away from the plate. In addition, we investigated the effects of variation of photon energies, sizes of radiation field and thickness of the plate. When the target to be irradiated is far from the thin titanium plate, the dose differs little from what it would be in the absence of a plate, though the dose escalation existed in front of the metal plate. PMID:20589117

Shimozato, Tomohiro; Yasui, Keisuke; Kawanami, Ryota; Habara, Kousaku; Aoyama, Yuichi; Tabushi, Katsuyoshi; Obata, Yasunori

2010-01-01

63

Distal Femoral Osteotomy in Genovalgum: Internal Fixation with Blade Plate Versus Casting  

PubMed Central

Background: To compare the results of two different ways of distal femoral osteotomy stabilization in patients suffering from genuvalgum: internal fixation with plate, and casting. Methods: In a non-randomized prospective study, after distal femoral osteotomy with the zigzag method, patients were divided into two groups: long leg casting, and internal fixation with blade plate. For all patients, questionnaires were filled to obtain data. Information such as range of motion, tibiofemoral anatomical angle and complications were recorded. Results: 38 knees with valgus deformity underwent distal femoral supracondylar osteotomy. (8 with plaster cast and 30 with internal fixation using a blade plate). Preoperative range of motion was 129±6° and six months later it was 120±14°. The preoperative tibiofemoral angle was 32±6°; postoperative tibiofemoral angles were 3±3°, 6±2°, and 7±3° just after operation, six months, and two years later, respectively. Although this angle was greater among the group stabilized with a cast, this difference was not statistically significant. In postoperative complications, over-correction was found in five, recorvatom deformity in one, knee stiffness in three and superficial wound infection was recorded in three knees. Conclusions: There is no prominent difference in final range of motion and alignment whether fixation is done with casting or internal fixation. However, the complication rate seems higher in the casting method. PMID:25692152

Makhmalbaf, Hadi; Moradi, Ali; Ganji, Saeid

2014-01-01

64

Lateral fixation of open AO type-B2 ankle fractures: the Knowles pin versus plate  

Microsoft Academic Search

Forty-seven patients with open lateral malleolar (AO type-B2) fractures treated with copious irrigation and radical debridement,\\u000a reduction, and immediate fixation by Knowles pins or lateral plates were retrospectively reviewed with an average follow-up\\u000a period of 29 months. The 47 patients were divided into two groups, based on the method of treatment. The Knowles pin group\\u000a included 25 patients. The plate group

Yih-Shiunn Lee; Shu-Wen Chen

2009-01-01

65

A preliminary study of bending stiffness alteration in shape changing nitinol plates for fracture fixation.  

PubMed

Nitinol is a promising biomaterial based on its remarkable shape changing capacity, biocompatibility, and resilient mechanical properties. Until now, very limited applications have been tested for the use of Nitinol plates for fracture fixation in orthopaedics. Newly designed fracture-fixation plates are tested by four-point bending to examine a change in equivalent bending stiffness before and after shape transformation. The goal of stiffness alterable bone plates is to optimize the healing process during osteosynthesis in situ that is customized in time of onset, percent change as well as being performed non-invasively for the patient. The equivalent bending stiffness in plates of varying thicknesses changed before and after shape transformation in the range of 24-73% (p values <0.05 for all tests). Tests on a Nitinol plate of 3.0 mm increased in stiffness from 0.81 to 0.98 Nm² (corresponding standard deviation 0.08 and 0.05) and shared a good correlation to results from numerical calculation. The stiffness of the tested fracture-fixation plates can be altered in a consistent matter that would be predicted by determining the change of the cross-sectional area moment of inertia. PMID:21286815

Olender, Gavin; Pfeifer, Ronny; Müller, Christian W; Gösling, Thomas; Barcikowski, Stephan; Hurschler, Christof

2011-05-01

66

Lamina replacement with titanium plate fixation improves spinal stability after total lumbar laminectomy.  

PubMed

Biomechanical experiments and strain analyses were performed to investigate the effects of lamina replacement surgery for intraspinal lesions on postoperative spinal stability. Eight specimens of thoracic and lumbar vertebrae (T12-L4) were collected from adult cadavers. Stepwise lumbar total laminectomy, and laminoplasty with lamina reduction and replacement was undertaken in combination with titanium-plate fixation to simulate the surgical setting. The effects of thoracic and lumbar vertebral strain, displacement, and rigidity on spinal stability were measured following both single and multiple segment laminectomy. Significant differences in mechanical indices of stability were seen between stepwise laminectomy of lumbar vertebrae and normal specimens (p < 0.05), between lamina replacement in combination with titanium-plate fixation and laminectomy (p < 0.05), and between single- and multiple-segment laminectomy (p < 0.05). Differences between laminoplasty with lamina replacement in combination with titanium-plate fixation and normal specimens need to be examined for further study. Lumbar laminectomy followed by reduction and replacement, in combination with titanium-plate fixation, was shown to be beneficial in terms of preserving spinal stability and maintaining biomechanical function and spinal loading capability. PMID:25169703

Nong, Luming; Zhou, Dong; Xu, Nanwei; Du, Rui; Jiang, Xijia

2015-12-01

67

Nicoya earthquake rupture anticipated by geodetic measurement of the locked plate interface  

NASA Astrophysics Data System (ADS)

The Nicoya Peninsula in Costa Rica is one of the few places on Earth where the seismically active plate interface of a subduction zone is directly overlaid by land rather than ocean. At this plate interface, large megathrust earthquakes with magnitudes greater than 7 occur approximately every 50 years. Such quakes occurred in 1853, 1900 and 1950, so another large earthquake had been anticipated. Land-based Global Positioning System (GPS) and seismic measurements revealed a region where the plate interface was locked and hence accumulated seismic strain that could be released in future earthquakes. On 5 September 2012, the long-anticipated Nicoya earthquake occurred in the heart of the previously identified locked patch. Here we report observations of coseismic deformation from GPS and geomorphic data along the Nicoya Peninsula and show that the magnitude 7.6 Nicoya earthquake ruptured the lateral and down-dip extent of the previously locked region of the plate interface. We also identify a previously locked part of the plate interface, located immediately offshore, that may not have slipped during the 2012 earthquake, where monitoring should continue. By pairing observations of the spatial extent of interseismic locking and subsequent coseismic rupture, we demonstrate the use of detailed near-field geodetic investigations during the late interseismic period for identifying future earthquake potential.

Protti, Marino; González, Victor; Newman, Andrew V.; Dixon, Timothy H.; Schwartz, Susan Y.; Marshall, Jeffrey S.; Feng, Lujia; Walter, Jacob I.; Malservisi, Rocco; Owen, Susan E.

2014-02-01

68

Biomechanical effects of plate area and locking screw on medial open tibial osteotomy.  

PubMed

Medial open high tibial osteotomy (HTO) has been used to treat osteoarthritis of the medial compartment of the knee. However, weaker plate strength, unstable plate/screw junction and improper surgery technique are highly related to the HTO outcomes. Two ?-shape plates were designed and eight variations (two supporting area × four locking stiffness) were compared by finite-element method. The computed tomography-based tibia was reconstructed and both wedge micromotion and implant stresses were chosen as the comparison indices. The construct was subjected to surgical and physiological loads. The medial-posterior region is the most loaded region and the load through the posterior leg is about four times that through the anterior leg. This indicates that the two-leg design can form a force-couple mechanism to effectively reduce the implant stresses. The use of locking screws significantly decrease the screw and hole stresses. However, the extending plate reduces the stresses of screws and holes above the wedge but makes the distal screws and holes much stressed. Wedge micromotion is affected by extending plate rather than locking screw. Three factors contribute to effective stabilisation of unstable HTO wedge: (1) intimate tibia-plate contact at medial-posterior regions, (2) sufficient rigidity at plate-screw junctions and (3) effective moment-balancing design at distal tibia-plate interfaces. PMID:24617553

Luo, Chu-An; Lin, Shang-Chih; Hwa, Su-Yang; Chen, Chun-Ming; Tseng, Ching-Shiow

2015-01-01

69

Clinical application of a new plate fixation system in open-door laminoplasty.  

PubMed

The purpose of this retrospective clinical series was to evaluate the benefits and complications of plate fixation for open-door laminoplasty in cervical spondylotic myelopathy with multilevel spinal stenosis compared with open-door laminoplasty without fixation. Forty-nine patients underwent open-door laminoplasty for cervical myelopathy with multilevel spinal stenosis with at least 13 months of follow-up. A plate was used as the sole method of fixation between the lateral mass and lamina with 3 screws. Computed tomography scans obtained pre- and postoperatively were assessed for plate complications and spinal canal enlargement. Pre- and postoperative neurological condition was assessed by the Japanese Orthopedic Association (JOA) myelopathy score. Overall cervical spine range of motion (ROM) was measured in full flexion and extension radiographs pre- and postoperatively. No restenosis due to door reclosure was noted, and no plates failed. No screws were backed out or broken. Almost all patients showed neurological improvement. The JOA score increased by 3.9±0.7 points in the suture group and 4.3±0.8 points in the plate group (P>.05). The postoperative increase in mean anteroposterior diameter of the spinal canal from C3 to C7 was 4.5±0.6 mm in the suture group and 5.1±0.5 mm in the plate group. The greater mean anteroposterior diameter increase in the plate group was statistically significant (P<.01). The mean cervical ROM decreased in the plate and suture groups postoperatively (P<.001). No significant difference was found in mean cervical ROM reduction between the groups (P>.05). No difference in axial symptoms was found between the 2 groups. PMID:22310411

Jiang, Liangjun; Chen, Weishan; Chen, Qixin; Xu, Kan; Wu, Qionghua; Li, Fangcai

2012-02-01

70

A biomechanical comparison of internal fixation techniques for ankle arthrodesis.  

PubMed

The purpose of the present study was to compare the primary bending stiffness characteristics of 5 different ankle arthrodesis fixation techniques: 3 compression screws, an anterior locking plate, a lateral locking plate, an anterior locking plate with a compression screw, and a lateral locking plate with a compression screw. A total of 25 full-scale anatomic models consisting of fourth-generation composite tibiae and tali were tested using an Instron 4505 Universal Testing System. We hypothesized that the use of a compression screw with a locking plate would add considerable stiffness to the fixation construct compared with the use of a locking plate alone. The data have shown that an anterior or lateral plate with a compression screw provides significantly greater stiffness than both a plate and 3 compression screws used individually. No significant difference was seen between the anterior plate with a compression screw and the lateral plate with a compression screw. No significant differences were found among the use of an anterior plate, a lateral plate, or 3 compression screws. We have concluded that when using a locking plate in an anterior or lateral configuration, the addition of a compression screw will considerably increase the primary bending stiffness of ankle arthrodesis. PMID:25116232

Clifford, Craig; Berg, Scott; McCann, Kevin; Hutchinson, Byron

2015-01-01

71

The Mechanical Benefit of Medial Support Screws in Locking Plating of Proximal Humerus Fractures  

PubMed Central

Background The purpose of this study was to evaluate the biomechanical advantages of medial support screws (MSSs) in the locking proximal humeral plate for treating proximal humerus fractures. Methods Thirty synthetic left humeri were randomly divided into 3 subgroups to establish two-part surgical neck fracture models of proximal humerus. All fractures were fixed with a locking proximal humerus plate. Group A was fixed with medial cortical support and no MSSs; Group B was fixed with 3 MSSs but without medial cortical support; Group C was fixed with neither medial cortical support nor MSSs. Axial compression, torsional stiffness, shear stiffness, and failure tests were performed. Results Constructs with medial support from cortical bone showed statistically higher axial and shear stiffness than other subgroups examined (P<0.0001). When the proximal humerus was not supported by medial cortical bone, locking plating with medial support screws exhibited higher axial and torsional stiffness than locking plating without medial support screws (P?0.0207). Specimens with medial cortical bone failed primarily by fracture of the humeral shaft or humeral head. Specimens without medial cortical bone support failed primarily by significant plate bending at the fracture site followed by humeral head collapse or humeral head fracture. Conclusions Anatomic reduction with medial cortical support was the stiffest construct after a simulated two-part fracture. Significant biomechanical benefits of MSSs in locking plating of proximal humerus fractures were identified. The reconstruction of the medial column support for proximal humerus fractures helps to enhance mechanical stability of the humeral head and prevent implant failure. PMID:25084520

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

2014-01-01

72

Bioabsorbable plates and screws fixation in mandible fractures: clinical retrospective research during a 10-year period.  

PubMed

We present the basic guidelines for the safe fixation of a mandible fracture using a bioabsorbable system with less strength than the metallic system based on our 10 years of experience.We conducted a retrospective review of 75 patients who had undergone fixation using a bioabsorbable system for a mandible fracture. We analyzed the method of fixation and the size and thickness of the plates and screws that were selected depending on the mandible's fracture site.Minor complications including intraoral wound disruptions and infections occurred in 12 (16%) patients, and 2 (2.7%) patients among 10 patients who presented with infections had nonunion; therefore, they underwent replacement of the absorbable system with the titanium system. Bone resorption that was caused by the absorbable plate occurred in 12 (16%) patients.The bioabsorbable system also may be able to replace the metallic system in the fixation of comminuted mandible fractures if further research on the development of the system is supported. PMID:25551864

Rha, Eun Young; Paik, Hyewon; Byeon, Jun Hee

2015-04-01

73

Sternal plate fixation for sternal wound reconstruction: initial experience (Retrospective study)  

PubMed Central

Background Median sternotomy infection and bony nonunion are two commonly described complications which occur in 0.4 - 5.1% of cardiac procedures. Although relatively infrequent, these complications can lead to significant morbidity and mortality. The aim of this retrospective study is to evaluate the initial experience of a transverse plate fixation system following wound complications associated with sternal dehiscence with or without infection following cardiac surgery. Methods A retrospective chart review of 40 consecutive patients who required sternal wound reconstruction post sternotomy was performed. Soft tissue debridement with removal of all compromised tissue was performed. Sternal debridement was carried using ronguers to healthy bleeding bone. All patients underwent sternal fixation using three rib plates combined with a single manubrial plate (Titanium Sternal Fixation System®, Synthes). Incisions were closed in a layered fashion with the pectoral muscles being advanced to the midline. Data were expressed as mean ± SD, Median (range) or number (%). Statistical analyses were made by using Excel 2003 for Windows (Microsoft, Redmond, WA, USA). Results There were 40 consecutive patients, 31 males and 9 females. Twenty two patients (55%) were diagnosed with sternal dehiscence alone and 18 patients (45%) with associated wound discharge. Thirty eight patients went on to heal their wounds. Two patients developed recurrent wound infection and required VAC therapy. Both were immunocompromised. Median post-op ICU stay was one day with the median hospital stay of 18 days after plating. Conclusion Sternal plating appears to be an effective option for the treatment of sternal wound dehiscence associated with sternal instability. Long-term follow-up and further larger studies are needed to address the indications, benefits and complications of sternal plating. PMID:21529357

2011-01-01

74

Open reduction and internal fixation of posterior pilon fractures with buttress plate  

PubMed Central

Objective: Posterior pilon fractures are rare injuries and have not yet gained well recognition. The purpose of this study was to present the treatment outcome for patients with posterior pilon fractures treated with buttress plate. Method: In this retrospective study we identified patients with posterior pilon fractures of the distal tibia who had undergone open reduction and internal fixation at our institute. Between January 2007 and December 2009, 10 patients (mean age, 46.5 years) who had undergone buttress plating via either a posterolateral approach or a dual posterolateral-posteromedial approach, were selected. All 10 patients were available for follow-up. The clinical outcome was evaluated with the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score and the visual analogue scale (VAS). The radiological evaluation was performed using the osteoarthritis-score (OA-score). Results: Satisfactory reduction and stable fixation were accomplished in all patients. At a mean follow-up of 36.2 months, all patients had good radiological results and showed satisfactory clinical recovery. The mean AOFAS sore was 87.8, the mean OA-score was 0.6, and the mean VAS scores during rest, active motion, and weight-bearing walking were 0.6, 0.8, and 1.4, respectively. Conclusion: Buttress plating for posterior pilon fractures gave satisfactory clinical outcomes. It also ensured rigid fixation which in turn enabled earlier postoperative mobilization. Level of Evidence IV, Retrospective Study. PMID:24644421

Chen, Da-wei; Li, Bing; Aubeeluck, Ashwin; Yang, Yun-feng; Zhou, Jia-qian; Yu, Guang-rong

2014-01-01

75

Ulnar styloid fracture in distal radius fractures managed with volar locking plates: to fix or not?  

PubMed

Distal radius fracture is usually associated with ulnar styloid fracture. Whether to fix the ulnar styloid or not remains a surgical dilemma as some surgeons believe that their repair is imperative while others feel that they should be managed conservatively. This prospective study involved 47 patients with unilateral fracture of the distal radius who met the inclusion criterion and underwent open reduction and internal fixation with volar locking plates; 28 patients (12 males and females?=?16) had an associated ulnar styloid fracture (Group A) while 19 (7 males; 12 females) did not have any ulnar styloid fracture (Group B). At the time of final evaluation both the groups were compared clinically by measuring the grip strength and range of motion around the wrist and the radiologically by measuring radial angle, radial length, volar angle and ulnar variance. Subjective assessment was done using DASH score and final assessment using Demerit point system of Saito. In Group A, average time for consolidation was 9.4 weeks, 17 patients developed non-union of the ulnar styloid, average DASH scores was 4.4 and according to Demerit point system of Saito, there were 78.5 % excellent, 17.9 % good and 3.6 % fair results; there were 2 cases of loss of reduction out of which one had persistent ulnar sided wrist pain. In Group B the average time for consolidation was 10.2 weeks, average DASH score was 3.8.and Demerit point system of Saito yielded 78.9 % excellent, 15.8 % good and 5.3 % fair results. There was one case of loss of reduction and one case of carpal tunnel syndrome which was managed conservatively. Both groups attained excellent range of motion, grip strength and well maintained the post operative radiological parameters. The comparison of clinico-radiological parameters in both groups was found to be statistically insignificant. To conclude, ulnar styloid fracture or its non union does not affect the outcome of an adequately fixed distal end radius fracture. We urge caution in electing operative treatment of non-united fracture of the ulnar styloid until better scientific report for treatment of pain associated with these fracture is available. PMID:25414551

Gogna, Paritosh; Selhi, Harpal Singh; Mohindra, Mukul; Singla, Rohit; Thora, Ankit; Yamin, Mohammad

2014-12-01

76

Internal fixation of pertrochanteric fractures using DHS with a two-hole side-plate  

PubMed Central

Pertrochanteric fracture in a group of 41 patients was internally fixed using a DHS with a two-hole side-plate. There were 20 male and 21 female patients with a mean age of 74 years. Thirty-two patients were followed up for more than one year and their final results were evaluated. There were 30 stable (31A1) and only two unstable (31A2) fractures. The average surgical time was 28 minutes, the average length of incision was 5.5 cm. All the patients, with one exception, healed without complications in anatomical position with good function of the hip joint. The only complication was caused by pulling-out of the plate from the femur in the fourth postoperative week when the patient (31A2 fracture) fell out of bed. A DHS with a four-hole side-plate was used at reoperation; subsequently the fracture had healed. Based on the results in this series of patients, the authors recommend fixation of stable pertrochanteric fractures with DHS and a two-hole side-plate. As proven by the authors, the benefit of DHS with a two-hole side-plate as compared to DHS with a four-hole side-plate is a shorter surgical time (28 and 36 minutes, respectively). PMID:19730862

?íha, Daniel

2009-01-01

77

A comparative study of blade plate fixation and external fixation in osteotomies for slipped capital femoral epiphysis.  

PubMed

We have performed corrective osteotomies for moderate or severe slipped capital femoral epiphysis (SCFE) using an original blade plate (BP) until 2006 and using a hybrid external fixator (EF) since 2007. We designed a comparative study of the short-term results between BP and EF devices in the treatment of proximal femoral osteotomies in SCFE. Nineteen SCFE patients (12 BP; seven EF) who underwent corrective osteotomies at our institution were included. Clinical and radiographic valuables including the operative time, intraoperative blood loss, postoperative improvement of head shaft angle, and posterior tilting angle, Harris hip score, limb-length discrepancy, and associated complications were compared between the two groups. Although there were no significant differences between the two groups in postoperative improvement of head shaft angle and posterior tilting angle, Harris hip score, and limb-length discrepancy, the EF group showed significantly shorter operative time and less intraoperative blood loss. Serious complications were observed in two patients of the BP group (deep infection and chondrolysis, respectively) and one of the EF group (chondrolysis). Percutaneous proximal femoral osteotomy using an EF appears to be safe, easy, and effective in correcting multiplanar deformities associated with SCFE. It has potential advantages over commonly used open techniques in terms of simplicity and less invasiveness. PMID:23797857

Kitoh, Hiroshi; Kitakoji, Takahiko; Hattori, Tadashi; Kaneko, Hiroshi; Mishima, Kenichi; Matsushita, Masaki; Ishiguro, Naoki

2013-11-01

78

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

PubMed

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. PMID:21146439

Fouad, H

2011-05-01

79

Comparison of Results between Hook Plate Fixation and Ligament Reconstruction for Acute Unstable Acromioclavicular Joint Dislocation  

PubMed Central

Background In the present study, we aimed to compare clinical and radiographic outcomes between hook plate fixation and coracoclavicular (CC) ligament reconstruction for the treatment of acute unstable acromioclavicular (AC) joint dislocation. Methods Forty-two patients who underwent surgery for an unstable acute dislocation of the AC joint were included. We divided them into two groups according to the treatment modality: internal fixation with a hook plate (group I, 24 cases) or CC ligament reconstruction (group II, 18 cases). We evaluated the clinical outcomes using a visual analog scale (VAS) for pain and Constant-Murley score, and assessed the radiographic outcomes based on the reduction and loss of CC distance on preoperative, postoperative, and final follow-up plain radiographs. Results The mean VAS scores at the final follow-up were 1.6 ± 1.5 and 1.3 ± 1.3 in groups I and II, respectively, which were not significantly different. The mean Constant-Murley scores were 90.2 ± 9.9 and 89.2 ± 3.5 in groups I and II, respectively, which were also not significantly different. The AC joints were well reduced in both groups, whereas CC distance improved from a mean of 215.7% ± 50.9% preoperatively to 106.1% ± 10.2% at the final follow-up in group I, and from 239.9% ± 59.2% preoperatively to 133.6% ± 36.7% at the final follow-up in group II. The improvement in group I was significantly superior to that in group II (p < 0.001). Furthermore, subluxation was not observed in any case in group I, but was noted in six cases (33%) in group II. Erosions of the acromion undersurface were observed in 9 cases in group I. Conclusions In cases of acute unstable AC joint dislocation, hook plate fixation and CC ligament reconstruction yield comparable satisfactory clinical outcomes. However, radiographic outcomes based on the maintenance of reduction indicate that hook plate fixation is a better treatment option. PMID:25729525

Yoon, Jong Pil; Lee, Byoung-Joo; Nam, Sang Jin; Chung, Seok Won; Jeong, Won-Ju; Min, Woo-Kie

2015-01-01

80

Transmucosal fixation of the fractured edentulous mandible.  

PubMed

Transmucosal fixation is a new strategy for the treatment of edentulous mandibular fractures using external fixation principles within the oral cavity. The component parts of this technique are not new. External fixation, locking plates and transmucosal implants represent the foundations of this technique; the authors' development has been to bring these established methods together as a transmucosal intra oral locking plate fixation technique. The first eight patients treated with this technique have achieved bony union, they have no long-term sensory deficit and all patients were able to eat a soft diet with minimal discomfort the day after surgery. The first five of eight patients on long-term review showed bony union confirmed radiographically. For the remainder and subsequent patients, radiographs have not been scheduled at review, in the absence of symptoms. PMID:21185150

Wood, G A; Campbell, D F; Greene, L E

2011-05-01

81

[Analysis of tendon injuries accompanying distal radius fractures using volar locking plates].  

PubMed

We examined 6 cases of tendon injuries that accompanied distal radius fractures using volar locking plate between April 2006 and March 2012. Male: one case, female: five cases, average age 57.0 (33~70) years old. The fracture type was A2 in one case, A3 in four cases, and C2 in one case by AO classification. The average period for operation waiting was 2.7 days. We analyzed the time of occurrence of tendon rupture (extensor pollicis longus (EPL)?flexor pollicis longus (FPL)), the existence or not of screw prominence and dorsal roof fragment, and the positioning of the plate setting. The tendon ruptures were EPL in four cases, and FPL in two cases. The average period of rupture occurrence was 86.8 (1~182) days. In four EPL tendon ruptures we recognized one marked screw prominence (16.7%), and two dorsal roof fragments (50%), both showing widespread displacement. Moreover, we recognized the malposition of the plate setting in the two cases of FPL tendon rupture (100%). The incidence of tendon ruptures accompanying distal radius fractures using volar locking plates was not low at all, therefore we should more pay attention to the prevention of this occurrence. PMID:25501757

Zenke, Yukichi; Oshige, Toshihisa; Menuki, Kunitaka; Yamanaka, Yoshiaki; Murai, Teppei; Furukawa, Kayoko; Sakai, Akinori

2014-12-01

82

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

PubMed

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 bending stiffness, torsional stiffness, and yield strength than a single 3.5mm LCP plate for osteotomies created 80mm from the trochlea. At the more distal osteotomy, dual plating was biomechanically superior. Our results suggest that single posterolateral column fixation of extra-articular humerus fractures is appropriate for more proximal fractures but that dual plate fixation is superior for more distal fractures. PMID:25249244

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

2014-12-01

83

The influence of distal locking on the need for fibular plating in intramedullary nailing of distal metaphyseal tibiofibular fractures.  

PubMed

Using human cadaver specimens, we investigated the role of supplementary fibular plating in the treatment of distal tibial fractures using an intramedullary nail. Fibular plating is thought to improve stability in these situations, but has been reported to have increased soft-tissue complications and to impair union of the fracture. We proposed that multidirectional locking screws provide adequate stability, making additional fibular plating unnecessary. A distal tibiofibular osteotomy model performed on matched fresh-frozen lower limb specimens was stabilised with reamed nails using conventional biplanar distal locking (CDL) or multidirectional distal locking (MDL) options with and without fibular plating. Rotational stiffness was assessed under a constant axial force of 150 N and a superimposed torque of ± 5 Nm. Total movement, and neutral zone and fracture gap movement were analysed. In the CDL group, fibular plating improved stiffness at the tibial fracture site, albeit to a small degree (p = 0.013). In the MDL group additional fibular plating did not increase the stiffness. The MDL nail without fibular plating was significantly more stable than the CDL nail with an additional fibular plate (p = 0.008). These findings suggest that additional fibular plating does not improve stability if a multidirectional distal locking intramedullary nail is used, and is therefore unnecessary if not needed to aid reduction. PMID:24589796

Attal, R; Maestri, V; Doshi, H K; Onder, U; Smekal, V; Blauth, M; Schmoelz, W

2014-03-01

84

Tidal triggering of earthquakes in the subducting Philippine Sea plate beneath the locked zone of the plate interface in the Tokai region, Japan  

Microsoft Academic Search

We found a characteristic space–time pattern of the tidal triggering effect on earthquake occurrence in the subducting Philippine Sea plate beneath the locked zone of the plate interface in the Tokai region, central Japan, where a large interplate earthquake may be impending. We measured the correlation between the Earth tide and earthquake occurrence using microearthquakes that took place in the

Sachiko Tanaka; Haruo Sato; Shozo Matsumura; Masakazu Ohtake

2006-01-01

85

Immediate open anterior reduction and antero-posterior fixation\\/fusion for bilateral cervical locked facets  

Microsoft Academic Search

Summary Background. Bilateral cervical locked facets is a severe traumatic lesion, most frequently resulting in tetraplegia. The common treatment strategy has been an attempt of awake, closed reduction, adding general anesthesia, muscle relaxation and manual traction in difficult cases. In cases of failed closed reduction, open reduction has most commonly been performed by a posterior approach. Patients in the current

2005-01-01

86

Derotational femoral osteotomy technique with locking nail fixation for adolescent femoral antetorsion: surgical technique and preliminary study.  

PubMed

Rotational femoral osteotomies for excessive femoral antetorsion may be considered only for symptomatic adolescents. Our main objective was to describe our femoral osteotomy technique. Preoperative planning was performed clinically and with the EOS imaging system. Percutaneous osteotomy was performed on distal femoral metaphysis under radioscopic control. Fixation was achieved with an antegrade locking nail. Rotation was checked precisely using a specially designed protractor before distal locking. We carried out a prospective pilot study between 2009 and 2010 on six patients (nine procedures). All the patients included presented a symptomatic femoral antetorsion greater than 20°. Clinical parameters including range of hip mobility and femoral antetorsion were measured every 2 months during the first 6 months, and then every year until skeletal maturation was reached. We obtained orthoroentgenograms using the same technique at each follow-up and torsional analysis by EOS 3D Imaging at 6 months. The average correction of the femoral antetorsion was 19.0 ± 4.0° (range, 13-25°). The average time of union was 3 ± 1.2 months (range, 2-6 months). Patients returned to full weight bearing at an average of 2.6 ± 0.4 months (range, 2-4 months). One patient experienced an early secondary displacement in varus for which a reoperation was required. We believe that this technique can accurately achieve derotational femoral osteotomies. A study is ongoing to evaluate the clinical results of this technique including mechanical and cosmetic advantages. PMID:25153645

Pailhé, Régis; Bedes, Laurent; Sales de Gauzy, Jerôme; Tran, Richard; Cavaignac, Etienne; Accadbled, Franck

2014-11-01

87

Long-term results after non-plate head-preserving fixation of proximal humeral fractures  

PubMed Central

A retrospective study was conducted to evaluate displaced proximal humeral fractures treated with a non-plate head-preserving fixation and to detect factors predicting functional outcome. After a median follow-up period of 79.7 months, 105 patients with nine A-fractures, 36 B-fractures and 60 C-fractures (nine two-part-fractures, 41 three-part fractures and 55 four-part fractures) were assessed. Functional outcome was measured based on the Constant and UCLA scores. Of all patients, 70–75% had excellent or good Constant and UCLA scores. In 74% a good or satisfactory quality of initial reduction fracture was achieved. About one-fifth (21%) of the fractures showed a secondary displacement. Twenty-seven percent of the patients had signs of humeral head necrosis and 22% had implant related problems. There were significant correlations between a high final score and young age, low AO fracture severity, good quality of fracture reduction and residual osseous deformity, absence of secondary fracture displacement, implant-related complications, shoulder arthrosis and humeral head necrosis at the time of follow-up. In conclusion, the non-plate head-preserving fixation of proximal humeral fractures is an alternative treatment for displaced proximal humeral fractures. Especially in severely displaced C-fractures in older patients, non-anatomical reduction leads to a high rate of secondary displacement, residual osseous deformity and only a fair shoulder function. For these cases alternative methods such as prosthetic replacement should be chosen. PMID:19705115

Bahrs, Christian; Rolauffs, Bernd; Weise, Kuno; Zipplies, Sebastian; Dietz, Klaus; Eingartner, Christoph

2009-01-01

88

Use of mineralized collagen bone graft substitutes and dorsal locking plate in treatment of elder metaphyseal comminuted distal radius fracture  

NASA Astrophysics Data System (ADS)

Bone graft may be needed to fill bone defect in elderly patients with a metaphyseal comminuted distal radius fracture. In this retrospective, nonrandomized, single-surgeon study, we evaluated the clinical and radiologic outcomes of using both dorsal locking plates with or without augmentation with mineralized collagen (MC) bone graft for elderly patients with dorsally metaphyseal comminuted radius fractures. Patients in group 1 ( n = 12) were treated with dorsal locking plates with MC bone graft application into the metaphyseal bone defect, and those in group 2 ( n = 12) only with dorsal locking plates. Clinical and radiologic parameters were determined at three and 12 months after surgery. At final follow-up, no significant difference was noted between the 2 groups in terms of palmar tilt and radial inclination ( p = 0.80); however, ulnar variance increased significantly in the group 2 treated with dorsal locking plates without augmentation ( p < 0.05). Functionally, there was no significant difference between the groups. Our preliminary study suggests that combination of MC as bone-graft substitutes and dorsal locking plates may be a usefully alternative for elderly patients with metaphyseal comminuted distal radius fracture.

Liu, Ke-Bin; Huang, Kui; Teng, Yu; Qu, Yan-Zheng; Cui, Wei; Huang, Zhen-Fei; Sun, Ting-Fang; Guo, Xiao-Dong

2014-03-01

89

Mid-term functional outcome after the internal fixation of distal radius fractures  

E-print Network

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...

Phadnis, Joideep; Trompeter, Alex; Gallagher, Kieran; Bradshaw, Lucy; Elliott, David S; Newman, Kevin J

2012-01-26

90

New techniques and alternative fixation for the lapidus arthrodesis.  

PubMed

Arthrodesis of the first metatarsocuneiform joint is a powerful and durable procedure to help correct moderate to severe hallux valgus and/or first ray hypermobility. However, painful nonunion remains a notoriously high potential outcome. Research regarding locking plates seems promising, and data show lower rates of nonunion. Innovative fixation techniques are new and should be considered in the future as further literature is available on their long-term use. Regardless of the fixation, proper joint preparation and good compression is fundamentally the most important. A case of Lapidus fusion with locking plates after a failed arthrodesis with screws alone is presented. PMID:23827494

Young, Nathan J; Zelen, Charles M

2013-07-01

91

Internal fixation of shaft humerus fractures by dynamic compression plate or interlocking intramedullary nail: a prospective, randomised study.  

PubMed

Compare the results of internal fixation of shaft of humerus fractures using dynamic compression plating (DCP) or antegrade interlocking intramedullary nail (IMN). Fifty patients with diaphyseal fracture of the shaft of the humerus and fulfilling the inclusion criterion were randomly assigned to one of the two groups. Twenty-five patients were managed with closed antegrade interlocking intramedullary nail, and 25 underwent open reduction and internal fixation using dynamic compression plating. The mean age of patients with IMN fixation was 37.28 years (SD 12.26) and 37.72 years (SD 12.70) for those who underwent plating. Road traffic accident was the most common mode of injury in both groups. There was a statistically significant difference between the two groups with respect to duration of hospital stay, operative time and blood loss. There was no significant difference between the two groups in terms of union or complications. The functional assessment at the end of 1 year between the two groups did not show any significant difference in outcome. Antegrade interlocking IMN and DCP fixation are comparable when managing diaphyseal shaft of humerus fractures with respect to union rates and complications. Although shoulder related complications are more in the IMN group, however, it is associated with shorter hospital stay, lesser operative time and less blood loss. This makes interlocking IMN an effective option in managing these fractures. PMID:25408496

Wali, Mir G R; Baba, Asif N; Latoo, Irfan A; Bhat, Nawaz A; Baba, Omar Khurshid; Sharma, Sudesh

2014-11-01

92

Torsion properties of biological fixation utilizing a plate with and without an intramedullary rod  

E-print Network

The goal of internal fixation procedures is the restoration of normal structure and function to the injured bone. Internal fixation devices are utilized to increase the stability of fracture segments, transfer loads across the fracture site...

Keiser, Michael

1995-01-01

93

Open Reduction Internal Fixation of Distal Clavicle Fracture With Supplementary Button Coracoclavicular Fixation  

PubMed Central

Distal clavicle fractures are common, and no standard treatment exists. Many different surgical modalities exist. This report describes an open reduction internal fixation technique that achieves both plate and coracoclavicular stabilization using a button device. A precontoured superior-lateral plate is secured to the clavicle. A 3.2-mm spade-tipped drill bit is drilled across the clavicle and coracoid, passing through 4 cortices. The button is loaded onto an insertion device, passed across the 4 cortices, and captured on the undersurface of the coracoid under fluoroscopic guidance. This construct is linked to the distal clavicle plate by heavy sutures using a second button that sits in the plate. The lateral locking holes are then filled to finalize fixation. This technique provides for a simplified way to achieve coracoclavicular stabilization when using a plate for fixation of distal clavicle fractures. PMID:25473604

Hanflik, Andrew; Hanypsiak, Bryan T.; Greenspoon, Joshua; Friedman, Darren J.

2014-01-01

94

Immunoelectron microscopic study of proteoglycans in rat epiphyseal growth plate cartilage after fixation with ruthenium hexamine trichloride (RHT)  

Microsoft Academic Search

The localization of proteoglycans in rat epiphyseal growth plate cartilage was investigated immunoelectron microscopically by the post-embedding method, using mouse monoclonal antibody (2-B-6) which specifically recognizes 4-sulphated chondroitin or dermatan sulphate after digestion of proteoglycans with chondroitinase ABC. Fixation with ruthenium hexamine trichloride (RHT) and embedding in LR White served to preserve chondrocytes in the expanded state and matrix proteoglycans

H. Hagiwara

1992-01-01

95

Characterizing Plate Re-locking and Mantle Viscoelastic Response Following the 2010 Maule Mw 8.8 Megathrust Earthquake  

NASA Astrophysics Data System (ADS)

Following a subduction zone mega-earthquake we observe afterslip on the plate interface which is predominantly aseismic and can release as much as 20% of the moment release of the coseismic slip. However, as the postseismic period progresses the afterslip rate decays and the seismogenic zone begins to re-lock. Re-locking is manifested in the data by a turnaround of the GPS vectors from trenchwards to a convergence-parallel direction and a decrease in aftershock b-value. Due to the viscoelastic relaxation of the mantle we see a sustained trenchward displacement as we move futher away from the plate interface and into the backarc, concurrent with the turnaround of the stations closer to the plate interface. The excellent spatial coverage of continuous GPS stations in the region affected by the Maule Mw=8.8 2010 earthquake, combined with the proximity of the coast to the seismogenic zone, allows us to study subduction plate interface kinematics in unprecedented detail. Here we present geodetic evidence for re-locking of the seismogenic plate interface using over 3 years of postseismic data from continuous and campaign GPS stations close to the seismogenic zone. We attempt to characterize the process of re-locking using Finite Element Modelling of the South-Central Chilean subduction margin. Modelling proceeds by introducing a coseismic stress change and varying the parameters of rate-and-state friction along the plate interface to fit the vector turnaround of the near-field GPS stations. The data further towards the back-arc are used to constrain the linear Maxwell viscoelastic response of the mantle in a separate modeling step; the contribution of the viscoelastic relaxation to the surface displacement is then subtracted from the dataset to give a refined estimate of surface displacements due to plate interface kinematics. By analyzing the time dependent linear Maxwell viscoelastic parameters we attempt to deduce the most likely constitutive models of mantle viscoelasticity.

Bedford, Jonathan; Moreno, Marcos; Baez, Juan Carlos; Bartsch, Mitja; Heidbach, Oliver; Oncken, Onno; Rosenau, Matthias; Tilmann, Frederik; Tassara, Andrés

2014-05-01

96

Biomechanical study in polyurethane mandibles of different metal plates and internal fixation techniques, employed in mandibular angle fractures.  

PubMed

The aim of this study was to perform a physicochemical and morphological characterization and compare the mechanical behavior of an experimental Ti-Mo alloy to the analogous metallic Ti-based fixation system, for mandibular angle fractures. Twenty-eight polyurethane mandibles were uniformly sectioned on the left angle. These were divided into 4 groups: group Eng 1P, one 2.0-mm plate and 4 screws 6 mm long; group Eng 2P, two 2.0-mm plates, the first fixed with 4 screws 6 mm long and the second with 4 screws 12 mm long. The same groups were created for the Ti-15Mo alloy. Each group was subjected to linear vertical loading at the first molar on the plated side in a mechanical testing unit. Means and standard deviations were compared with respect to statistical significance using ANOVA. The chemical composition of the Ti-15Mo alloy was close to the nominal value. The mapping of Mo and Ti showed a homogeneous distribution. SEM of the screw revealed machining debris. For the plates, only the cpTi plate undergoes a surface treatment. The metallographic analysis reveals granular microstructure, from the thermomechanical trials. A statistically significant difference was found (P < 0.05) when the comparison between both internal fixation techniques was performed. The 2P technique showed better mechanical behavior than 1P. PMID:25340696

Semeghini Guastaldi, Fernando Pozzi; Hochuli-Vieira, Eduardo; Guastaldi, Antonio Carlos

2014-11-01

97

A novel murine model of established Staphylococcal bone infection in the presence of a fracture fixation plate to study therapies utilizing antibiotic-laden spacers after revision surgery.  

PubMed

Mice are the small animal model of choice in biomedical research due to the low cost and availability of genetically engineered lines. However, the devices utilized in current mouse models of implant-associated bone infection have been limited to intramedullary or trans-cortical pins, which are not amenable to treatments involving extensive debridement of a full-thickness bone loss and placement of a segmental antibiotic spacer. To overcome these limitations, we developed a clinically faithful model that utilizes a locking fracture fixation plate to enable debridement of an infected segmental bone defect (full-thickness osteotomy) during a revision surgery, and investigated the therapeutic effects of placing an antibiotic-laden spacer in the segmental bone defect. To first determine the ideal time point for revision following infection, a 0.7 mm osteotomy in the femoral mid-shaft was stabilized with a radiolucent PEEK fixation plate. The defect was inoculated with bioluminescent Staphylococcus aureus, and the infection was monitored over 14 days by bioluminescent imaging (BLI). Osteolysis and reactive bone formation were assessed by X-ray and micro-computed tomography (micro-CT). The active bacterial infection peaked by 5 days post-inoculation, however the stability of the implant fixation became compromised by 10-14 days post-inoculation due to osteolysis around the screws. Thus, day 7 was defined as the ideal time point to perform the revision surgery. During the revision surgery, the infected tissue was debrided and the osteotomy was widened to 3mm to place a poly-methyl methacrylate spacer, with or without vancomycin. Half of the groups also received systemic vancomycin for the remaining 21 days of the study. The viable bacteria remaining at the end of the study were measured using colony forming unit assays. Volumetric bone changes (osteolysis and reactive bone formation) were directly measured using micro-CT image analysis. Mice that were treated with local or systemic vancomycin did not display gross pathology at the end of the study. While localized vancomycin delivery alone tended to decrease the bacterial burden and osteolysis, these effects were only significant when combined with systemic antibiotic therapy. This novel mouse model replicates key features of implant-associated osteomyelitis that make treatment extremely difficult, such as biofilm formation and osteolysis, and imitates the clinical practice of placing an antibiotic-laden spacer after infected tissue debridement. In addition, the model demonstrates the limitations of current PMMA spacers and could be an invaluable tool for evaluating alternative antimicrobial treatments for implant-associated bone infection. PMID:25459073

Inzana, Jason A; Schwarz, Edward M; Kates, Stephen L; Awad, Hani A

2015-03-01

98

Quality of life after volar locked plating: a 10-year follow-up study of patients with intra-articular distal radius fractures  

PubMed Central

Background This study aimed to present functional results and patient’s health related quality of life (HRQOL) data ten years after volar locked plate fixation (VPF) of unstable intra-articular distal radial fractures (DRF). Methods Thirty-nine patients with a mean age of sixty-one years were operatively treated with VPF after intra-articular distal radial fractures. They were evaluated two, six, and ten years postoperatively according to the Gartland and Werley score. For subjective evaluation the Short Form 36 (SF-36) and the Disability of Arm, Shoulder and Hand (DASH) questionnaires were adopted. Results Overall, wrist function did not differ significantly two, six and ten years after the operation. Over 90% patients achieved “good” or “excellent” results ten years after surgery according to the Gartland and Werley score. Ten years postoperatively the results of the SF 36 did not differ significantly from the two- and six-year follow-up. Overall findings from the SF-36 did not differ significantly from the data of Austrian and American norm populations. Only in the subscale of mental health (MH) the ten-year follow-up did show significantly poorer results (p?=?0.045) compared to the Austrian norm population. The median DASH scores did not show significant differences during the ten-year follow-up period. Conclusion The ten-year results of this single-center study suggest that operative treatment of intra-articular DRF with volar locked plates is a useful and satisfactory therapy option, both in terms of function and HRQOL. PMID:25059690

2014-01-01

99

Walking ability of children with a hexapod external ring fixator (TSF®) and foot plate mounting at the lower leg.  

PubMed

Wearing an external fixator for several months can be expected to profoundly affect the ability to walk, but, in principle, full weight-bearing is possible during corrective procedures with the Taylor Spatial Frame (TSF). The present prospective cohort study was conducted to assess whether patients are able to walk with or without crutches during treatment with a TSF on the lower leg. Twenty-four patients (10 girls, 14 boys; average age 11 years, range 6-17) scheduled for fixator surgery with osteotomies in the lower leg and foot mounting were included. Dynamic foot loading during free walking was measured with plantar pressure measurements. The contact area, contact time and contact pressure on the foot plate were recorded and normalized to body weight. In the first postoperative week, all patients needed crutches and 67% showed partial weight-bearing. At the second measurement, about 6 weeks after surgery, 21% of the patients could walk without crutches and 58% were partially weight-bearing with crutches. On the day before fixator removal, 50% of the patients were fully weight-bearing without crutches and 38% were partially weight-bearing, but 12% could not bear any weight or were unable to walk. When a ring fixator is used to correct lower leg deformity and prevent equinus, there is minimal risk of complete dependence and abasia. This study shows that up to 88% of the pediatric patients are able to walk while wearing the fixator. Already a few days after surgery, two-thirds of the patients were partially weight-bearing with crutches, and only 12% needed a wheelchair and were not able to walk with the fixator. PMID:22682788

Schiedel, F; Vogt, B; Wacker, S; Pöpping, J; Bosch, K; Rödl, R; Rosenbaum, D

2012-07-01

100

Biomechanical evaluation with finite element analysis of the reconstruction of femoral tumor defects by using a double-barrel free vascularized fibular graft combined with a locking plate  

PubMed Central

The repair of large distal femoral tumor defects can be challenging for orthopedic surgeons. The combination of a double-barrel free vascularized fibular graft (DFVFG) with a locking plate is a viable option. However, the biomechanical influence of the fibular bone length on the locking plate attachment is unclear. We aimed to evaluate the stability of the distal femoral defect after reconstruction with fibular grafts of different lengths. A three-dimensional model of a healthy volunteer was developed using computed tomography images. A locking plate and bicortical screws were constructed and registered with CAD. Four models were defined (6 cm, 8 cm, 10 cm, and 12 cm bone grafts). The models were imported into finite element analysis software. Boundary-constrained and load conditions were applied. The model stress distribution and displacement were statistically analyzed. The Von Mises stress distributions were similar between the 6 cm, 8 cm, and 10 cm bone grafts and locking plate within each of those bone defect models (P > 0.05), while the Von Mises stress distribution was significantly higher in the 12 cm model than the other 3 lengths for both the bone graft and locking plate (P < 0.05). Significantly greater Von Mises stress was observed at the 12 cm bone graft and locking plate than with the shorter bone grafts. Therefore, we recommend that, to avoid complications, the bone graft should not exceed 12 cm when using FVFG in combination with a locking plate while treating a distal femoral tumor defect. PMID:25356094

Ma, Limin; Zhou, Ye; Zhang, Yu; Zhou, Xia; Yao, Zilong; Huang, Wenhan; Qiao, Guoqing; Xia, Hong

2014-01-01

101

Did the 2010 Chile earthquake change the locking degree at neighboring plate interface segments of the Andean subduction zone?  

NASA Astrophysics Data System (ADS)

A widely held view is that lateral extents and magnitudes of great earthquakes are fundamentally controlled by the stress build-up along the plate interface as inferred from the degree of locking. Therefore, inferring the distribution of locking and its along-strike variations has become an essential tool for seismic and tsunami hazard assessment. Recent studies have explored the main parameters affecting the spatial distribution of locking degree, but the time evolution of locking has not yet been clearly documented. Here we used time-series of continuous GPS at adjacent segments (> 500 km distance) to the rupture zone of the 2010 Chile (Mw=8.8) earthquake to explore the differences in locking degree before (2008-2010) and after (2010-2013) this event. Results suggest that the interseismic velocity (landward displacements) increased both in the northern (27°S-32°S) and southern (41°S-45°S) unruptured segments. The variations of displacements can be explained by an increase and homogenization of the locking degree at areas that were creeping before the 2010 earthquake. The estimated increase of locking degrees have peaks of about 20% and 100% for the northern and southern regions respectively. The b-value, which parameterizes the frequency-magnitude distribution of seismicity, decreased after the 2010 earthquake in the northern segment (in the southern segment there is not enough seismicity for estimating b-value) from 1.2 to 0.7 indicating a tendency for asperities to be brought closer to failure due to increase of shear stresses on the plate interface. By means of a 3D thermo-mechanical subduction model we are able to simulate the dynamic response of the system and study the stress variations before and after the earthquake, supporting the rearrangment of shear stresses at adjacent segments. Our results suggest that locking degree can evolve over a short timescale due to the change of the stress regime induced by great earthquakes. We propose that the seismic cycle along a margin is a self-organized system in the sense of a lateral connected evolution of build-up and release of stress at different seismotectonic segments. Importantly, the 2010 earthquake may have increased the seismic potential of the northern and southern neighboring plate interface segments, which broke last in 1922 and 1960, respectively.

Moreno, Marcos; Báez, Juan Carlos; Bedford, Jonathan; Quinteros, Javier; Tassara, Andres; Melnick, Daniel; Oncken, Onno; Vigny, Christophe; Bartsch, Mitja; Bevis, Michael; Soto, Hugo; Barrientos, Sergio; Ortega, Ismael; Valderas, Maria

2014-05-01

102

Do fluids control locking and seismic slip on the subduction fault? - evidence from the Chilean plate boundary  

NASA Astrophysics Data System (ADS)

A number of recent studies have suggested that the interseismic locking degree inverted from geodetic data at convergent plate boundaries may be closely related to slip distribution of subsequent megathrust earthquakes as found recently for the Maule 2010 and Tohoku 2011 earthquakes. The physical nature of locking, however, remains a matter of debate. We explore seismic, seismological and geodetic data collected from the southern part of the Maule 2010 earthquake rupture zone - overlapping with the northern termination of the Valdivia 1960 earthquake - in the decade before the event to identify the spatial variability of pore fluid pressure and effective stress along the plate interface zone. The reflection seismic and the seismological data exhibit well defined changes of reflectivity and Vp/Vs ratio along the plate interface that can be correlated with different parts of the coupling zone as well as with changes during the seismic cycle. High Vp/Vs domains, interpreted as zones of elevated pore fluid pressure, spatially correlate with lower locking degree, and exhibit higher background seismicity as expected for partly creeping domains. In turn, unstable slip associated to a higher degree of locking is promoted in lower pore fluid pressure domains. This relationship is particularly well expressed in the upper two thirds of the seismic coupling zone down to a depth of some 25 km at an estimated 250°C. In the gradient zone towards deeper domains locking gradually decreases to very low values, and the elevated Vp/Vs-ratio returns to standard values. At the same time seismic reflectivity remains high to some 35 km and then disappears with only minor S-wave reflectivity persisting down to the zone of intermediate depth seismicity at some 60 km depth that is again highlighted by bright reflections. This transition zone, at temperatures > 250°C is also largely coincident with aftershock clusters and a concentration of geodetically recorded afterslip following the Maule earthquake. From their spatial interrelationship, we suggest similar, but less strongly expressed activity of an overpressured fluid. We demonstrate that variations of pore pressure at the plate interface control locking degree variations and therefore coseismic slip distribution of large earthquakes. Lateral variations of pore fluid pressure may be related to the subduction of a transform zone (Maule fracture zone) responsible for part of the fluid input. Finally, we speculate that pore pressure increase during the terminal stage of a seismic cycle to close to lithostatic pressure with an equivalent reduction of effective strength may be as relevant for earthquake triggering as stress loading from long-term plate convergence.

Oncken, Onno; Moreno, Marcos; Haberland, Christian; Rietbrock, Andreas; Angiboust, Samuel; Bedford, Jon

2014-05-01

103

Heterogeneous plate locking in the South–Central Chile subduction zone: Building up the next great earthquake  

Microsoft Academic Search

We use Global Positioning System (GPS) velocities and kinematic Finite Element models (FE-models) to infer the state of locking between the converging Nazca and South America plates in South–Central Chile (36°S?46°S) and to evaluate its spatial and temporal variability. GPS velocities provide information on earthquake-cycle deformation over the last decade in areas affected by the megathrust events of 1960 (Mw=9.5)

M. Moreno; D. Melnick; M. Rosenau; J. Bolte; J. Klotz; H. Echtler; J. Baez; K. Bataille; J. Chen; M. Bevis; H. Hase; O. Oncken

2011-01-01

104

Palmar locking plates for corrective osteotomy of latent malunion of dorsally tilted distal radial fractures without structural bone grafting.  

PubMed

The purpose of this retrospective study was to investigate the clinical and radiological outcomes following corrective osteotomy for nascent malunion of distal radial fractures with dorsal tilt using palmar-locking plates without using autologous structural bone grafting for dorsal cortex support. The fractures were dorsally angulated distal radial fractures (AO types A2, A3, and C1) with neglected or delayed treatment for 5 to 8 weeks. Fractures were repaired using 2.4-mm palmar locking plates. Dorsal cortical defects at the osteotomy sites were filled with incipient healing callus. Radiographs were obtained before correction and at 2 and 6 weeks and 3, 4.5, 6, and 12 months postoperatively. Palmar tilt, radial inclination, and ulnar variance were measured. There were no cases of loss reduction, implant failure, or delayed fracture union without structural bone graft and casting. Clinical assessments included active range of motion of the wrist and function based on the Mayo Wrist Score. Even with wrist immobilization for >1 month preoperatively, all patients had excellent Mayo Wrist Scores at 4.5 months due to early postoperative rehabilitation. No further changes were apparent between 4.5- and 12-month follow-up.The palmar locking plates provided sufficient stability for corrective osteotomy within 8 weeks of injury without the need for structural bone grafting. Furthermore, casting immobilization was also unnecessary, and a good wrist range of motion was restored early after rehabilitation. PMID:21667904

Tarng, Yih-Wen; Yang, Shan-Wei; Hsu, Chien-Jen

2011-06-01

105

A prospective trial of poly-L-lactic/polyglycolic acid co-polymer plates and screws for internal fixation of mandibular fractures.  

PubMed

The aim of this study was to test the performance of poly-L-lactic/polyglycolic acid (PLLA/PGA) co-polymer plates and screws in the fixation of mandibular fractures. Following clinical and radiographic examination, internal fixation was achieved with PLLA/PGA co-polymer plates and screws in 31 patients. Elastic maxillomandibular fixation was maintained for 4 weeks and a blenderized diet for 6 weeks. Patients were followed up at 1 week, 6 weeks, and 3, 6 and 12 months post surgery, and evaluated clinically for swelling, pain, mucosal discoloration and occlusal relation. Segment stability, fracture healing and screw-hole ossification were assessed radiographically. Of the 29 patients who completed the trial, 20 had an uncomplicated postoperative period, resulting in complete bone union. Radiographic evidence of screw-hole ossification was noted in several patients, with considerable site-dependent rate variation. Nine patients developed complications ranging from minor dehiscence (4 patients) to frank sepsis requiring plate removal (5 patients), resulting in a 22.5% complication rate. There were no cases of non-union at the end of the fixation period. The reported complication rate following titanium internal fixation of mandibular fractures is 13.7%-43%. PLLA/PGA co-polymer plate and screw fixation of mandibular fractures, although technically more challenging and costly, is a viable alternative to traditional metal devices in selected patients. PMID:18295449

Ferretti, C

2008-03-01

106

Comparison of resorbable plates and titanium plates for fixation stability of combined mandibular symphysis and angle fractures  

PubMed Central

Objectives We compared resorbable plates with titanium plates for treatment of combined mandibular angle and symphyseal fractures. Materials and Methods Patients with mandibular angle and symphysis fractures were divided into two groups. The control (T) group received titanium plates while the experimental (R) group received resorbable plates. All procedures were carried out under general anesthesia using standard surgical techniques. We compared the frequency of wound dehiscence, development of infection, malocclusion, malunion, screw breakage, and any other technical difficulties between the two groups. Results Thirteen patients were included in the R group, where 39 resorbable plates were applied. The T group consisted of 16 patients who received 48 titanium plates. The mean age in the R and T groups was 28.29 and 24.23 years, respectively. Primary healing of the fractured mandible was obtained in all patients in both groups. Postoperative complications were minor and transient. Moreover, there were no significant differences in the rates of various complications between the two groups. Breakage of 3 screws during the perioperative period was seen in the R group, while no screws or plates were broken in the T group. Conclusion Resorbable plates can be used to stabilize combined mandibular angle and symphysis fractures. PMID:25551093

Lim, Ho-Yong; Jung, Chang-Hwa; Kim, Seong-Yong; Cho, Jin-Yong; Ryu, Jae-Young

2014-01-01

107

Comparison of two different double-plate fixation methods with olecranon osteotomy for intercondylar fractures of the distal humeri of young adults  

PubMed Central

Although several studies have demonstrated good results with open reduction and internal fixation of intercondylar fractures of the distal humerus, few have specifically addressed the results of such surgical fixation in young adults. The purpose of this study was to compare the clinical outcomes in patients with intercondylar fractures of the distal humerus treated using two different double-plating methods. Twenty-five patients with distal humeral fractures classified as type C according to the Association for Osteosynthesis/Association for the Study of Internal Fixation (AO/ASIF) classification system, who were admitted to the Second Hospital Affiliated to Anhui Medical University (Hefei, China) from October 2008 to October 2011, were included in the study. The patients were treated with two different double-plate fixation and olecranon osteotomy methods. Thirteen patients were treated by perpendicular plating (group I) and twelve patients by Y-shaped double-plating in the coronal plane (group II). All the patients were followed up for 12–38 months, with an average of 19.2±7.1 months in group I and 18.3±4.0 months in group II. All the osteotomies and fractures had healed by the final follow-up. Complications developed in 4 patients in group I and 3 patients in group II. According to the Mayo Elbow Performance Scores (MEPS), 84.6% of patients in group I and 83.3% in group II had excellent or good scores. No significant differences were identified between the clinical outcomes of the two plating methods. The olecranon osteotomy approach with double-plate fixation is a good choice for the surgical treatment of type C intercondylar fractures in young adult distal humeri. The two plating methods provide solid fixation, permit early rehabilitation and result in satisfactory clinical outcomes. PMID:23935736

TIAN, DASHENG; JING, JUEHUA; QIAN, JUN; LI, JIANMING

2013-01-01

108

Comparison of single coracoclavicular suture fixation and hook plate for the treatment of acute unstable distal clavicle fractures  

PubMed Central

Background Surgical managements are recommended for unstable distal clavicle fractures because of a high incidence of nonunion. A variety of methods have been previously reported, but there is no current consensus regarding which method is the most suitable. Methods Between December 2004 and August 2010, we treated 68 patients with Neer type IIB distal clavicle fractures using single coracoclavicular suture fixation with Mersilene tape (M group) or clavicular hook plate (H group). Sixty-eight patients were followed at least 24 months (mean, 37.9 months). We retrospectively compared the functional outcome, parameters, and perioperative course of the two treatments. Statistical analysis was performed with independent sample t test and chi-square test. Results The M group presented significantly less operation time (P?=?0.005) and intra-operative blood loss (P?=?0.010) than the H group. The mean University of California at Los Angeles (UCLA) shoulder rating scale, Oxford shoulder score, VAS scale, and satisfaction score revealed no significant difference between the M group and the H group. The M group had better range of motion in the operated shoulder during forward flexion and abduction at 3 and 6 months postoperatively. However, the range of motion at 1 and 2 years after operation revealed almost the same results. Two acromial osteolysis and one acromial fracture were noted in the H group and one superficial wound infection and one frozen shoulder in the M group during follow-up. Finally, there was no significant difference in the complication rate between the two groups, and all fractures achieved union clinically at final follow-up. Conclusions Both single coracoclavicular suture fixation and clavicular hook plate offered effective treatment in acute unstable distal clavicle fractures. However, single coracoclavicular suture fixation with Mersilene tape provided early recovery of shoulder motion and avoided further morbidity of the acromion. PMID:24885387

2014-01-01

109

Therapeutic effects of minimally invasive adjustable and locking compression plate for unstable pelvic fractures via posterior approach  

PubMed Central

Objective: Unstable pelvic fractures are clinically complex injuries. Selecting appropriate treatment remains a challenging problem for orthopedic physicians. The aim of this study is to compare the clinical effects of minimally invasive adjustable plate and locking compression plate in treatment of unstable pelvic fractures via posterior approach. Methods: From January 2009 to June 2012, fifty-six patients with unstable pelvic fractures were included. After at least 12-month follow-up, forty-four patients treated with two methods were enrolled in the study and divided into two groups: minimally invasive adjustable plate (group A) and locking compression plate (group B). Preoperative and postoperative radiography was taken to assess the fracture displacement and reduction quality. The size of incision, operation duration, blood loss, duration of X-ray exposures, Majeed postoperative functional evaluation and Lindahl postoperative reduction evaluation were analyzed. Results: The mean follow-up in group A was 27.3 months (range, 13-48 months), and that in group B was 21.8 months (range, 12-42 months). There were no iatrogenic neurovascular injuries during the operations in the two groups. In group B, malunion was observed in one patient, and infection of incision was observed in one case. The operation duration, blood loss, and size of incision of group A were significantly less than that of group B. There was no significant difference in the duration of X-ray exposures between the two groups. The Majeed functional evaluation score in group A was significantly higher than that in group B. The difference of the imaging score of the retained displacement was not statistically significant. Conclusions: Both the two methods can effectively stabilize the unstable pelvic fractures. However, the minimally invasive adjustable plate has the advantages of minimally invasive, less radiation exposure, technically safe and time saving. Minimally invasive adjustable plate is a good supplementary option for treating posterior pelvic ring injuries. PMID:25785063

Wu, Tao; Chen, Wei; Zhang, Qi; Li, Xu; Lv, Hong-Zhi; Yang, Guang; Zhang, Ying-Ze

2015-01-01

110

Use of a single 2.0-mm locking AO reconstruction titanium plate in linear, non-comminuted, mandible fractures  

PubMed Central

Purpose: The aim of the following study is to prospectively evaluate the use of a single Arbeitsgemeinschaft für Osteosynthesefragen (AO) 2.0-mm locking reconstruction plate for linear non-comminuted mandibular fractures without the use of a second plate. Materials and Methods: This study consisted of a sample of 10 patients who reported to the department with fractures of the mandible and were treated over a period of 24 months from November 2010 to November 2012. Out of these, there were 8 male patients and 2 female patients. There were four cases of isolated parasymphysis fractures, 1 of the case had a parasymphysis fracture associated with subcondylar fracture, 4 had a body fracture and 2 had a symphysis fracture. Results: All patients had satisfactory fracture reduction and a successful treatment outcome without major complications. Only one patient (10%) developed minor complications. Conclusion: The study has demonstrated that treating linear non-comminuted mandibular fractures with a single AO 2.0-mm locking reconstruction plate provides excellent stability at the fracture site which in turn leads to sound bone healing and early functional rehabilitation. PMID:24987599

Parmar, Babu S.; Makwana, Kalpesh G.; Patel, Aditi M.; Tandel, Ramanuj C.; Shah, Jay

2014-01-01

111

A parametric analysis of bone fixation plates on fractured equine third metacarpal  

E-print Network

. In order to try to eliminate this dilemma, veterinary ortho- pedic surgeons and materials and structural engineers at Texas A&M have teamed together to analyze and evaluate existing plate designs and to make recommendations for thai. r improvement...

Ray, Donald Reagan

1970-01-01

112

Biomechanical study of different plate configurations for distal humerus osteosynthesis.  

PubMed

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. PMID:25663513

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

2015-05-01

113

Biodegradable internal fixation plates enabled with X-ray visibility by a radiopaque layer of ?-tricalcium phosphate and poly (lactic-co-glycolic acid).  

PubMed

Biodegradable polymer plates can be clinically used as an alternative to metal plates (e.g., titanium) for internal fixation, which, however, are not visible with X-ray imaging, often used for post-operative diagnostics. In this study, therefore, we prepared a biodegradable plate enabled with X-ray visibility by attaching a radiopaque layer on a biodegradable fixation plate in clinical use (Inion, Finland). A radiopaque layer was made of a fine powder of a radiopaque agent, ?-tricalcium phosphate (TCP) and a biodegradable binder material, poly (lactic-co-glycolic acid) (PLGA), which were physically mixed without change in their chemical structure. The radiopacity increased as we increased the layer thicknesses from 0.5 mm to 1.3 mm. Regardless of layer thickness, however, the radiopacity decreased with time both in vitro and in vivo due to decreasing density of TCP in the layer by swelling and degradation of a binder material, PLGA. The in vivo study with rabbits revealed that a discernible image of the radiopaque plate could be obtained by X-ray for up to 21 days, also showing the overall biocompatibility 6 months after implantation. Therefore, we conclude that the radiopaque plate prepared in this work is a promising fixation device enabled with both X-ray visibility and biodegradability. PMID:23165646

Shasteen, Catherine; Kwon, Seok Min; Park, Keun Yung; Jung, Sun Young; Lee, Seung Ho; Park, Chun Gwon; Kim, Myung Hun; Kim, Sukwha; Son, Woo-Chan; Choi, Tae Hyun; Choy, Young Bin

2013-02-01

114

A Comparative Outcomes Study Using the Volar Locking Plating System for Distal Radius Fractures in both Young Adults and Adults Older than 60 Years  

PubMed Central

Purpose Despite the high prevalence and impact of distal radius fractures (DRFs) on older patients, the current available literature regarding DRFs in older adults lacks adequate comparative treatment data. The purpose of this prospective, controlled outcomes study is to compare outcomes using the volar locking plating system (VLPS) for DRFs in both older and younger adults. Methods Consecutive, eligible patients were enrolled into our prospective study over a two-year period on the basis of strict inclusion/exclusion criteria. Subjects were entered into two cohorts based on age: 20–40 years and ? 60 years. Patient outcomes and complication rates were evaluated at three, six and twelve months after surgery. Outcome measures included the Michigan Hand Outcomes Questionnaire (MHQ), grip strength, active wrist and forearm range of motion, the Jebsen-Taylor test, and radiographic parameters. Results 55 patients (30 young and 25 older adults) with unilateral, inadequately reduced DRFs were enrolled and received surgical treatment with the VLPS. We observed no statistically significant difference in any of the outcomes for all three follow-up periods. While older age patients continued to improve throughout their twelve month postoperative visits, younger patients achieved their maximum recovery during the six month follow-up period, suggesting different recovery patterns. At the twelve-month assessment, older patients were able to achieve a higher mean MHQ score than their younger counterparts (normalized mean: 85% and 82%, respectively). Complication rates were similar between the two groups for all three time periods, with most occurring on or before the three month postoperative visit. Conclusions This study indicates that the VLPS is successful in managing DRFs in older patients and without increased complications compared to younger patients. For the older patients without prohibitive surgical risks, internal fixation using the VLPS yields comparable outcomes to younger patients. Level of Evidence Level II prospective comparative study PMID:18656749

Chung, Kevin C.; Squitieri, Lee; Kim, H. Myra

2015-01-01

115

Leg length discrepancy treatment with subtrochanteric shortening osteotomy and blade plate fixation.  

PubMed

Background. Subtrochanteric femoral shortening osteotomy is a method of surgical treatment of lower limb discrepancy (LLD). It is less commonly used due to numerous limitations and the resulting decrease in height, which is an undesirable effect for most patients. The aim of this study was to analyze the results and complications of treatment of leg length discrepancy (LLD) by femoral shortening osteotomy fixed with a blade plate and screws. Material and methods. The study group comprised 18 patients treated by subtrochanteric shortening osteotomy fixed with a blade or straight plate and screws. The age of patients at the time of the operation ranged from 12 years and two months to 24 years and 3 months (mean 17 years and 8 months). Before the operation, the mean LLD amounted to 4.1cm (from 2,5 to 7,0). The size of the same-time resection of the femur at the level of the subtrochanteric osteotomy ranged from 2.5 cm to 5.0 cm (mean 3.7). The follow-up period ranged from 6 months to 15 years and 9 months (mean 3 years and 6 months). The analysis of the results was based on the following criteria. A good result was defined as obtaining an equal length of both legs or achieving the intended amount of shortening. A fair result was defined as a post-operative LLD from 0.5 cm to 1 cm. A poor result comprised patients with post-operative LLD greater than 1 cm or with complications that leave a lasting impact or complications requiring revision surgery. Results. A good result was obtained in 15 patients and a fair one in 3 patients. Complications appeared in 5 (28%) patients. The most common complication was delayed bone healing. Full weight -bearing of the operated limb was allowed between 12 and 32 weeks post-surgery (mean 19 weeks). The final LLD ranged from 0 cm to 3 cm (mean 0.6 cm). Equal limb length was obtained in 13 (72%) patients. Conclusions. 1. Subtrochanteric femoral shortening osteotomy fixed with a plate and screws, taking into consideration the limitation of possible correction to 5-6 cm, is an effective method of treatment of lower limb discrepancy with a relatively low complication rate. 2. The most common complications of subtrochanteric shortening osteotomy are disorders of bone union. 3. The use of lag screws for stabilisation of the osteotomy with an angle plate may reduce the risk of complications. PMID:25404626

Koczewski, Pawe?; Zaklukiewicz, Aleksandra; Rotter, Iwona

2014-08-28

116

Minimally invasive proximal interphalangeal joint arthrodesis using a locking compression plate and tissue engineering in horses: a pilot study.  

PubMed

This pilot study assessed the efficacy of 2 minimally invasive techniques for proximal interphalangeal (PIP) joint arthrodesis in horses. The PIP joints of both forelimbs (n = 6) were stabilized with locking compression plates (LCP) using a minimally invasive technique (LCP technique). Subsequently, for 1 randomly selected PIP joint of each horse, surgical drilling (SurD) was performed and tissue engineering (TE) was applied (LCP/SurD/TE technique). Minimally invasive PIP joint arthrodesis with LCP demonstrated low postoperative infection rates. Gross and histological evaluations revealed considerable destruction of the articular cartilage in the LCP/SurD/TE-treated joints. In contrast, almost no destruction of the cartilage was observed in the LCP-treated joints. Our results suggest that the LCP technique alone is not sufficient for PIP joint arthrodesis and that the LCP/SurD/TE technique may be useful for PIP joint arthrodesis in horses. PMID:25392547

Seo, Jong-pil; Yamaga, Takashi; Tsuzuki, Nao; Yamada, Kazutaka; Haneda, Shingo; Furuoka, Hidefumi; Tabata, Yasuhiko; Sasaki, Naoki

2014-11-01

117

Application of a medial buttress plate may prevent many treatment failures seen after fixation of vertical femoral neck fractures in young adults.  

PubMed

Femoral neck fractures in young adults with normal bone are mostly vertically oriented and may have variable amounts of comminution, which result from shearing forces during high-energy trauma. These factors play a role in the high rate of complications after this injury, including nonunion, malunion, failure of fixation, and avascular necrosis. These problems often occur together and inter-relate, for example, nonunion or malunion frequently result from fixation failure and varus collapse of the femoral head after reconstruction. The orthopaedic surgeon's goals of obtaining and maintaining anatomic reduction until bony union have been addressed by a number of surgical approaches and fixation constructs, however, complications are still common and no consensus exists on how these problematic fractures may be best treated. For optimal treatment of vertical femoral neck fractures, anatomic reduction must be achieved and fixation must be able to resist the high shear forces across the fracture with hip motion, weight-bearing, and muscle tone. Buttress plate fixation is a common method for stabilizing fractures that require resistance to shear forces and stands as one of the basic principles of fracture care. This technique has not been widely applied to this injury pattern. We propose that the concepts of modern fracture care should be applied together for vertical femoral neck fractures in young adults. Specifically, we propose that anatomic reduction and fixation of vertically oriented femoral neck fractures with the addition of a medial buttress plate to resist shearing forces will improve on the historically high rate of complications after these difficult injuries. PMID:25744726

Mir, Hassan; Collinge, Cory

2015-05-01

118

Dall-Miles cable and plate fixation for the treatment of peri-prosthetic femoral fractures-analysis of results in 13 cases.  

PubMed

We present a retrospective review of 13 patients with periprosthetic femoral fractures treated with the Dall-Miles cable and plate fixation system between 1995 and 1999. Of these, 12 fractures were in relation to hip arthroplasty and one was proximal to the femoral component of a total knee replacement. Mean age at presentation was 77 years (range 66-87) with the male female ratio of 6:7. All patients were followed up until there was evidence of clinical and radiological union. The average follow-up period was 6.5 months (range 2.5-24). We achieved satisfactory results in ten patients with average time to union of 4.4 months. The results were unsatisfactory in three patients who required further revision procedures due to failure of fixation or non-union. Internal fixation of the fracture with the loose femoral component left in-situ led to failure of union in one patient. Varus mal-alignment of the femoral component to the shaft of more than 6 degrees was associated with unsatisfactory outcome in two patients. The Dall-Miles cable and plate system is a useful method of internal fixation for majority of periprosthetic femoral fractures. This method may not be suitable if the femoral component is loose or if it is in varus angulation of more than 6 degrees to the shaft of the femur. PMID:11382425

Venu, K M; Koka, R; Garikipati, R; Shenava, Y; Madhu, T S

2001-06-01

119

Novel Pedicle Screw and Plate System Provides Superior Stability in Unilateral Fixation for Minimally Invasive Transforaminal Lumbar Interbody Fusion: An In Vitro Biomechanical Study  

PubMed Central

Purpose This study aims to compare the biomechanical properties of the novel pedicle screw and plate system with the traditional rod system in asymmetrical posterior stabilization for minimally invasive transforaminal lumbar interbody fusion (MI-TLIF). We compared the immediate stabilizing effects of fusion segment and the strain distribution on the vertebral body. Methods Seven fresh calf lumbar spines (L3-L6) were tested. Flexion/extension, lateral bending, and axial rotation were induced by pure moments of ± 5.0 Nm and the range of motion (ROM) was recorded. Strain gauges were instrumented at L4 and L5 vertebral body to record the strain distribution under flexion and lateral bending (LB). After intact kinematic analysis, a right sided TLIF was performed at L4-L5. Then each specimen was tested for the following constructs: unilateral pedicle screw and rod (UR); unilateral pedicle screw and plate (UP); UR and transfacet pedicle screw (TFS); UP and TFS; UP and UR. Results All instrumented constructs significantly reduced ROM in all motion compared with the intact specimen, except the UR construct in axial rotation. Unilateral fixation (UR or UP) reduced ROM less compared with the bilateral fixation (UP/UR+TFS, UP+UR). The plate system resulted in more reduction in ROM compared with the rod system, especially in axial rotation. UP construct provided more stability in axial rotation compared with UR construct. The strain distribution on the left and right side of L4 vertebral body was significantly different from UR and UR+TFS construct under flexion motion. The strain distribution on L4 vertebral body was significantly influenced by different fixation constructs. Conclusions The novel plate could provide sufficient segmental stability in axial rotation. The UR construct exhibits weak stability and asymmetrical strain distribution in fusion segment, while the UP construct is a good alternative choice for unilateral posterior fixation of MI-TLIF. PMID:25807513

Zhu, Qingan; Zhou, Yue; Li, Changqing; Liu, Huan; Huang, Zhiping; Shang, Jin

2015-01-01

120

The use of anterior Caspar plate fixation in acute cervical spine injury.  

PubMed

Optimal management of cervical cord injury in the presence of documented instability and/or compression of neural elements remains a controversial topic. Surgery and internal stabilization of cervical spine fracture/dislocations are effective and well accepted, but controversy exists on the relative merits of the anterior versus the posterior approach as well as the optimal timing of surgical intervention. We report our experience with the Caspar technique and instrumentation for anterior stabilization in 54 patients for acute cervical spine injury. Our series consists of 38 male and 16 female patients whose ages ranged from 16 to 68 years, with a mean age of 29.2 years. Thirty-two of these patients had complete neurological sensory/motor deficits at the time of presentation, eight were neurologically intact, and 14 had preservation of some motor and sensory function. All 54 patients had radiographic evidence of posterior instability as well as anterior disruption of either a vertebral body or intervertebral disk. We found that "early" intervention (less than 24 hours after injury) was performed frequently in the neurologically compromised patients. Twelve of the 22 patients undergoing surgery less than 24 hours after admission regained significant neurological function, with 13 of 22 developing postoperative complications. In the "delayed" group (surgery more than 24 hours after injury, mean 14.3 days), 14 patients experienced postoperative complications, with 15 of 24 demonstrating neurological improvement. The eight patients who were intact did uniformly well. There was no mortality during the follow-up. All 54 patients showed a solid fusion (clinically and radiologically) within 6 months of surgery. In two cases the plates had to be removed, without risking the fusion. Our experience suggests that although anterior cervical fusion and Caspar plating remain appropriate for patients with documented anterior compromise of the canal, it should not substitute for more traditional posterior stabilization procedures. Because this route has the potential for more serious complications, it should be reserved for the cases in which anterior decompression is deemed necessary or posterior fusion was unsuccessful. With appropriate selection of patients, no adverse effect of early surgery was demonstrated. In fact, neurologically compromised patients had the benefits of increased ease of patient care and early transfer to rehabilitation. PMID:1876968

Randle, M J; Wolf, A; Levi, L; Rigamonti, D; Mirvis, S; Robinson, W; Bellis, E; Greenberg, J; Salcman, M

1991-09-01

121

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

PubMed

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. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 103B:596-607, 2015. PMID:24964903

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

122

A novel technique for pediatric femoral locked submuscular plate removal: the ‘push-pull’ technique  

PubMed Central

Submuscular and minimally invasive plate insertion is gaining popularity reducing the need for large open approaches and resulting in a smaller operative ‘footprint.’ With pediatric fractures and titanium implants, fibrous and osseous ingrowth to the implant and osseous implant integration may interfere with implant removal. Therefore, the small minimally invasive implant insertion procedure may require a large maximally invasive exposure for implant removal after fracture healing. To reduce soft tissue damage, bleeding, scarring, and pain associated with implant removal, a minimally invasive procedure utilizing the pre-existing incisions while controlling the implant is efficient and beneficial. The surgical technique is described, and a case series of 21 treated pediatric femoral fractures illustrates the successful performance of the procedure and its limitations. PMID:23844650

2013-01-01

123

Guided bone regeneration technique in the esthetic zone: a novel approach using resorbable PLLA-PGA plates and screw fixation. A case report.  

PubMed

The use of biodegradable fixation materials or devices during maxillofacial, craniofacial, and orthopedic reconstructive surgical procedures reduces or eliminates the need to perform a second surgical procedure, which would otherwise be required to remove a nonbiodegradable device. This article presents a novel approach to augment a horizontally deficient alveolar ridge using both a resorbable plate/screw fixation system composed of a polylactic acid-polyglycolic acid (PLLA-PGA) copolymer to provide a rigid scaffolding for the bone chips and a resorbable collagen barrier (Bio-Gide, Osteohealth) to secure the graft material. For periodontal reconstructive procedures, such as guided bone regeneration, the clinical application of this technique may be advantageous and also provide a more esthetic result by minimizing the need for an additional surgical procedure. (Int J Periodontics Restorative Dent 2009;29:543-547.). PMID:19888498

Fabbri, Giacomo; Brennan, Myra; Manfredi, Massimiliano; Ban, Georgio

2009-10-01

124

Open reduction and internal fixation versus casting for highly comminuted and intra-articular fractures of the distal radius (ORCHID): protocol for a randomized clinical multi-center trial  

Microsoft Academic Search

Background  Fractures of the distal radius represent the most common fracture in elderly patients, and often indicate the onset of symptomatic\\u000a osteoporosis. A variety of treatment options is available, including closed reduction and plaster casting, K-wire-stabilization,\\u000a external fixation and open reduction and internal fixation (ORIF) with volar locked plating. The latter is widely promoted\\u000a by clinicians and hardware manufacturers. Closed reduction

Christoph Bartl; Dirk Stengel; Thomas Bruckner; Inga Rossion; Steffen Luntz; Christoph Seiler; Florian Gebhard

2011-01-01

125

Use of a proximal humeral plate for a paediatric peri-prosthetic femoral fracture  

PubMed Central

In this case an 18-year-old female with cerebral palsy sustained a peri-prosthetic femoral fracture adjacent to a blade plate previously inserted for a femoral varus osteotomy. The injury was treated using a long proximal humeral locking plate. The existing blade plate was removed. The fracture was reduced and held, and a 10-hole PHILOS™ plate applied with near anatomical reduction. There were no post-operative complications. Radiographic union was confirmed at 11 months. To our knowledge, this is the first reported use of a PHILOS™ plate in the management of a femoral peri-prosthetic fracture and successfully demonstrated a straightforward method for revision fixation. PMID:24986984

Shaw, C.R.; Badhesha, J.; Ayana, G.; Abu-Rajab, R.

2014-01-01

126

Lateral fixation of AO type-B2 ankle fractures in the elderly: the Knowles pin versus the plate  

Microsoft Academic Search

The study was a retrospective evaluation and comparison. Seventy-five elderly patients (>50 years) with AO type-B2 ankle fractures\\u000a were treated by open reduction and internal fixation. All patients were followed up retrospectively for at least 12 months.\\u000a The 75 patients were divided into two groups, based on the method of treatment. The Knowles pin (KP) group included 45 patients\\u000a with an average

Yih-Shiunn Lee; Hui-Ling Huang; Ting-Ying Lo; Chien-Rae Huang

2007-01-01

127

Randomized prospective study of ACL reconstruction with interference screw fixation in patellar tendon autografts versus femoral metal plate suspension and tibial post fixation in hamstring tendon autografts: 5-year clinical and radiological follow-up results.  

PubMed

Patellar tendon graft has been the most frequently used material in anterior cruciate ligament (ACL) reconstruction, but the hamstring tendons have been increasingly used as well; however, which graft is to be preferred is not adequately supported by existing clinical studies. In this prospective randomized clinical trial, the study hypothesis was that the hamstring tendons are equally good graft material as the patellar tendon in ACL reconstruction. Ninety-nine patients with laxity due to a torn ACL underwent arthroscopically assisted reconstruction with graft randomization according to their birth year to either patellar tendon with metal interference screw fixation or double looped semitendinosus and gracilis tendons with fixation similar to the Endobutton technique using a titanium metal plate suspension proximally and screw-washer postdistally. Excluding preoperative Lysholm knee score, there were no significant differences between the two groups in the preoperative and operative data. A standard rehabilitation regimen was used for all the patients, including immediate postoperative mobilization without a knee brace, protected weight bearing for 2 weeks, and return to full activity at 6-12 months postoperatively. Forty patients in the patellar tendon group and 39 patients in the hamstring tendon group were available for clinical evaluation at median 5 years after surgery (ranges 3 years 11 months-6 years 7 months). The results revealed no statistically significant differences with respect to clinical and instrumented laxity testing, isokinetic muscle torque measurements, International Knee Documentation Committee ratings, Lysholm (knee score), Tegner (activity level) and Kujala patellofemoral knee scores. There was an enlargement of the drill tunnels, statistically more in the hamstring tendon group, but no increase from 2 to 5 years in either group. Narrowing of the joint spaces (IKDC measurement method) from 2 to 5 years postoperatively was seen in both the groups, however, without difference between the two groups. PMID:16552549

Harilainen, Arsi; Linko, Eric; Sandelin, Jerker

2006-06-01

128

Influence of the volume of bone defect, bone grafting methods, and hook fixation on stress on the Kerboull-type plate and screw in total hip arthroplasty: three-dimensional finite element analysis.  

PubMed

For total hip arthroplasty or revision surgery using acetabular reinforcement cross-plates, choosing between bulk and morselized bone grafts for filling acetabular defects is challenging. We used finite element model (FEM) analysis to clarify various stresses on the cross-plate based on bone defect size, bone graft type, and presence or absence of hook fixation to the bone. We constructed 12-pattern FEMs and calculated the maximum stress generated on the Kerboull-type (KT) plate and screw. Bone defects were classified into four patterns according to the volume. Regarding the bone graft type, bulk bone grafts were considered as cortical bone, and morselized bone grafts were considered to consist of cancellous bone. Models were compared based on whether hook fixation was used and whether a gap was present behind the plate. The upper surface of the host bone was fixed, and a 1,000-N load was imposed on the horizontal axis at 71°. Larger bone defects increased the stress on the KT plate and screws. This stress increased when no bone was grafted; it was lower when bulk cortical bone grafts were used for filling than when morselized cancellous bone grafts were used. For cortical bone grafts, the increased stress on the KT plate and screws was lowered with hook removal. Attaching the hook to the bone and filling the gap behind the KT plate with an adequate bone graft reduced the stress on the KT plate and screws, particularly for large bone defects filled by bulk bone grafting. PMID:24964969

Kaku, Nobuhiro; Hara, Katsutoshi; Tabata, Tomonori; Tsumura, Hiroshi

2015-02-01

129

Plate on Plate Osteosynthesis for the Treatment of Nonhealed Periplate Fractures  

PubMed Central

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. PMID:24967127

Nikolaou, Vassilios S.; Lacon, Andrew; Ashwood, Neil; Hamlet, Mark

2014-01-01

130

Does osteoporosis have a negative effect on the functional outcome of an osteoporotic distal radial fracture treated with a volar locking plate?  

PubMed

We performed a retrospective study to determine the effect of osteoporosis on the functional outcome of osteoporotic distal radial fractures treated with a volar locking plate. Between 2009 and 2012 a total of 90 postmenopausal women with an unstable fracture of the distal radius treated with a volar locking plate were studied. Changes in the radiological parameters of 51 patients with osteoporosis (group 1, mean age 66.9, mean T-score -3.16 (sd 0.56)) were not significantly different from those in 39 patients without osteoporosis (group 2, mean age 61.1, mean T-score -1.72 (sd 0.57)). The mean Disabilities of the Arm, Shoulder and Hand (DASH) score at final follow-up was 11.5 (sd 12.2) in group 1 and 10.5 (sd 13.25) in group 2. The mean modified Mayo wrist score at final follow-up was 79.0 (sd 14.04) in group 1 and 82.6 (sd 13.1) in group 2. However, this difference was not statistically significant (p = 0.35 for DASH score, p = 0.2 for modified Mayo wrist score). Univariable and multivariable logistic regression analysis showed that only the step-off of the radiocarpal joint was related to both a poor DASH and modified Mayo wrist score. Pearson's correlation coefficient showed a weak negative relationship only between the T-score and the change in volar tilt (intraclass coefficient -0.26, p = 0.02). We found that osteoporosis does not have a negative effect on the functional outcome and additional analysis did not show a correlation between T-score and outcome. Cite this article: Bone Joint J 2015;97-B:229-34. PMID:25628287

Choi, W-S; Lee, H J; Kim, D-Y; Lee, C-H; Lee, B G; Kim, J-H; Lee, K-H

2015-02-01

131

Locked up in America  

NSDL National Science Digital Library

FRONTLINE explores "America's fixation on incarceration" with this two-film report, Locked Up In America. Through the episodes "Solitary Nation" and "Prison State," viewers are offered a dramatic and intimate look at this pressing issue. First-time visitors can look at some short clips, including "Who's Locked Up in America" and "How Much Time U.S. Prisoners Spend in Solitary." Moving on, the site also includes a range of other materials, including teachers guidebooks and discussion questions, along with three separate podcasts. Visitors are also encouraged to leave their own comments and meditations.

132

Positive effect of removal of subchondral bone plate for cemented acetabular component fixation in total hip arthroplasty: a randomised RSA study with ten-year follow-up.  

PubMed

We hypothesised that the removal of the subchondral bone plate (SCBP) for cemented acetabular component fixation in total hip arthroplasty (THA) offers advantages over retention by improving the cement-bone interface, without jeopardising implant stability. We have previously published two-year follow-up data of a randomised controlled trial (RCT), in which 50 patients with primary osteoarthritis were randomised to either retention or removal of the SCBP. The mean age of the retention group (n = 25, 13 males) was 70.0 years (sd 6.8). The mean age in the removal group (n = 25, 16 males) was 70.3 years (sd 7.9). Now we have followed up the patients at six (retention group, n = 21; removal group, n = 20) and ten years (retention group: n = 17, removal group: n = 18), administering clinical outcome questionnaires and radiostereometric analysis (RSA), and determining the presence of radiolucent lines (RLLs) on conventional radiographs. RSA demonstrated similar translation and rotation patterns up to six years. Between six and ten years, proximal acetabular component migration and changes of inclination were larger in the retention group, although the mean differences did not reach statistical significance. Differences in migration were driven by two patients in the SCBP retention group with extensive migration versus none in the SCBP removal group. The significant difference (p < 0.001) in the development of radiolucent lines in the retention group, previously observed at two years, increased even further during the course of follow-up (p < 0.001). While recognising SCBP removal is a more demanding technique, we conclude that, wherever possible, the SCBP should be removed to improve the cement-bone interface in order to maximise acetabular component stability and longevity. PMID:25568411

Flivik, G; Kristiansson, I; Ryd, L

2015-01-01

133

Locking versus nonlocking construct in an osteoporotic, segmental fibula defect model.  

PubMed

Early studies on the treatment of osteoporotic distal fibular fractures suggest that poor bone quality can compromise fixation and, therefore, clinical outcome. Multiple prior biomechanical studies evaluated length-stable fracture models with destructive load-to-failure protocols, which may not represent a clinically relevant failure mode. The current authors compared a lateral locked construct with 2 distinct nonlocked constructs in an osteoporotic, segmental fibula defect model. Eighteen adult cadaveric ankles were randomized to a one-third tubular plate with nonlocking screws, a precontoured fibular plate with nonlocking screws, or the same pre-contoured plate with locking screws. Each was nondestructively loaded with an external rotation of 2.5 Nm for 10,000 cycles. The primary outcome was the change in construct stiffness. Secondary outcomes included maximal rotational displacement and change in insertion torques. Average increase in stiffness of the one-third tubular plate was 0.35 Nm/degree (P<.001), which was significantly greater than that in the nonlocking and locking precontoured plates (0.15 and 0.17 Nm/degree, respectively; P=.69). All 3 constructs externally rotated to 11.7°±4.6°, 8.6°±3.6°, and 10.9°±4.7°, respectively (P=.50). Average loss of insertion torque in the 4 proximal positions was 32.7%±19%, 41.3%±20.2%, 57.8%±19%, and 64.9%±29.2% (P>.05). Average loss in the 4 distal positions for nonlocking constructs (71.6%±21%, 70.4%±26.4%, 93.1%±11%, and 83.3%±35.4%) was significantly different from that for the locking construct (15%±21.4%, 11.7%±24%, 9.2%±9.2%, and 20.8%±23.3%) (P<.05). No evidence in the current study supports the use of a locking plate for osteoporotic specimens. PMID:24093701

Lo, Eddie Y; Tseng, Susan S; Christiansen, Blaine A; Lee, Mark A; Yoo, Brady J

2013-10-01

134

Treatment of segmental tibial fractures with supercutaneous plating.  

PubMed

Segmental tibial fractures usually follow a high-energy trauma and are often associated with many complications. The purpose of this report is to describe the authors' results in the treatment of segmental tibial fractures with supercutaneous locking plates used as external fixators. Between January 2009 and March 2012, a total of 20 patients underwent external plating (supercutaneous plating) of the segmental tibial fractures using a less-invasive stabilization system locking plate (Synthes, Paoli, Pennsylvania). Six fractures were closed and 14 were open (6 grade IIIa, 2 grade IIIb, 4 grade II, and 2 grade I, according to the Gustilo classification). When imaging studies confirmed bone union, the plates and screws were removed in the outpatient clinic. Average time of follow-up was 23 months (range, 12-47 months). All fractures achieved union. Median time to union was 19 weeks (range, 12-40 weeks) for the proximal fractures and 22 weeks (range, 12-42 weeks) for the distal fractures. Functional results were excellent in 17 patients and good in 3. Delayed union of the fracture occurred in 2 patients. All patients' radiographs showed normal alignment. No rotational deformities and leg shortening were seen. No incidences of deep infection or implant failures occurred. Minor screw tract infection occurred in 2 patients. A new 1-stage protocol using supercutaneous plating as a definitive fixator for segmental tibial fractures is less invasive, has a lower cost, and has a shorter hospitalization time. Surgeons can achieve good reduction, soft tissue reconstruction, stable fixation, and high union rates using supercutaneous plating. The current patients obtained excellent knee and ankle joint motion and good functional outcomes and had a comfortable clinical course. PMID:25102507

He, Xianfeng; Zhang, Jingwei; Li, Ming; Yu, Yihui; Zhu, Limei

2014-08-01

135

Evaluation of proximal femoral locking plate in unstable extracapsular proximal femoral fractures: Surgical technique & mid term follow up results?  

PubMed Central

Background Stable trochanteric femur fractures can be treated successfully with conventional implants such as sliding hip screw, cephalomedullary nails, angular blade plates. However comminuted and unstable inter or subtrochanteric fractures with or without osteoporosis are challenging & prone to complications. The PF-LCP is a new implant that allows angular stability by creating fixed angle block for treatment of complex, comminuted proximal femoral fractures. Method We reviewed 30 patients with unstable inter or subtrochanteric fractures, which were stabilized with PF-LCP. Mean age of patient was 65 years, and average operative time was 80 min. Patients were followed up for a period of 3 years (June 2010–June 2013). Patients were examined regularly at 3 weekly interval for signs of union (radiological & clinical), varus collapse (neck-shaft angle), limb shortening, and hardware failure. Result All patients showed signs of union at an average of 9 weeks (8–10 weeks), with minimum varus collapse (<10°), & no limb shortening and hardware failure. Results were analysed using IOWA (Larson) hip scoring. Average IOWA hip score was 77.5. Conclusion PF-LCP represents a feasible alternative for treatment of unstable inter- or subtrochanteric fractures.

Kumar, Nishikant; Kataria, Himanshu; Yadav, Chandrashekhar; Gadagoli, Bharath S.; Raj, Rishi

2014-01-01

136

21 CFR 888.3060 - Spinal intervertebral body fixation orthosis.  

Code of Federal Regulations, 2012 CFR

...SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3060 Spinal intervertebral body fixation...fixation orthosis is a device intended to be implanted made of titanium. It consists of various vertebral plates that are...

2012-04-01

137

21 CFR 888.3060 - Spinal intervertebral body fixation orthosis.  

Code of Federal Regulations, 2011 CFR

...SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3060 Spinal intervertebral body fixation...fixation orthosis is a device intended to be implanted made of titanium. It consists of various vertebral plates that are...

2011-04-01

138

21 CFR 888.3060 - Spinal intervertebral body fixation orthosis.  

Code of Federal Regulations, 2010 CFR

...SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3060 Spinal intervertebral body fixation...fixation orthosis is a device intended to be implanted made of titanium. It consists of various vertebral plates that are...

2010-04-01

139

21 CFR 888.3060 - Spinal intervertebral body fixation orthosis.  

Code of Federal Regulations, 2014 CFR

...SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3060 Spinal intervertebral body fixation...fixation orthosis is a device intended to be implanted made of titanium. It consists of various vertebral plates that are...

2014-04-01

140

21 CFR 888.3060 - Spinal intervertebral body fixation orthosis.  

Code of Federal Regulations, 2013 CFR

...SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3060 Spinal intervertebral body fixation...fixation orthosis is a device intended to be implanted made of titanium. It consists of various vertebral plates that are...

2013-04-01

141

Multifragmentary Tibial Pilon Fractures: Midterm Results After Osteosynthesis with External Fixation and Multiple Lag Screws  

PubMed Central

Osteosynthesis of intraarticular tibial pilon fractures is preferably achieved using locking plates via a minimally invasive technique. If combined with severe soft tissue damage there is a high risk of wound-healing deficits after plate osteosynthesis. Thus our aim was to find an alternative method of treatment for those cases with combined soft tissue injuries. We report on five cases with comminuted fractures of the joint surface combined with critical soft tissue condition that were treated with lag screws and external fixation (AO) applied across the ankle joint. All five patients were followed up, undergoing clinical and radiological examination. Using this approach we achieved fracture healing of comminuted fractures without further complications. Clinical follow-up after an average of 55.6 (36–75) months revealed a mean AOFAS score of 81 (62–100). We therefore propose combined treatment using lag screws with external fixation as a practical treatment option for those fractures for which lag screws combined with a locking plate are not feasible or when there is a high risk of wound-healing deficits due to severe soft tissue damage. PMID:23002413

Kiene, Johannes; Herzog, Jan; Jürgens, Christian; Paech, Andreas

2012-01-01

142

Intraoral epimucosal fixation for reducible maxillary fractures of the jaws; surgical considerations in comparison to current techniques.  

PubMed

Fractures of the jaw are often treated with rigid and stable internal fixation using plates or miniplates. Early surgery for jaw fractures is the optimal treatment; however, if a late treatment is begun, often the adoption of other protocols is needed. When the jaw fracture has one free bone fragment with 2 full-thickness lesions of mucoperiosteal soft tissues both on the buccal and palatal sides, the risk of resorption or necrosis is very high after elevating a mucoperiosteal flap for rigid fixation. For this reason, we developed an intraoral epimucosal fixation technique using self-locking screws and plates. Substantial advantages of this new technique, in comparison with other commonly used fixation techniques, consisted in the prevention of bone resorption or necrosis by safe and simple screw insertion procedure after manipulation of the fracture for reduction in closed surgery. Major indications for epimucosal fixation in closed surgery are the presence of jaw fractures without dislocation or reducible jaw fractures by manipulation particularly in edentulous patients. PMID:25318439

Cortese, Antonio; Savastano, Germano; Amato, Massimo; Pantaleo, Giuseppe; Claudio, Pier Paolo

2014-11-01

143

Far cortical locking screws in distal femur fractures.  

PubMed

Distal femur fractures routinely heal by secondary bone healing, which relies on interfragmentary motion. Periarticular locking plates are commonly used for fixation in distal femur fractures but are associated with a high nonunion rate, likely due to the stiffness of the constructs. Far cortical locking (FCL) screws are designed to allow micromotion at the near cortex while maintaining purchase in only the far cortex. Although clinical data are limited, these screws have been shown in biomechanical studies to provide excellent interfragmentary motion, and animal models have shown increased callus formation compared with traditional locking screws. The purpose of this study was to examine the clinical effects that FCL screws have on healing in distal femur fractures treated with locked constructs. In this retrospective case series, 15 patients with a distal femur fracture treated with MotionLoc screws (Zimmer, Warsaw, Indiana) were analyzed. Serial radiographs were evaluated for callus presence and time to union. All fractures were either 33-A3 or 33-C2 according to the AO classification system, and 5 (33%) were open. Bone loss was recorded in 2 patients. There were no nonunions, and average time to union was 24 weeks. There were no implant failures, and all 5 open fractures, including the 2 with bone loss, healed without intervention. There was 1 reoperation due to painful hardware. Although this is a small case series, these results are promising. Far cortical locking screws may provide the answer to the high nonunion rate associated with distal femur fractures treated with traditional locked constructs. [Orthopedics. 2015; 38(3):e153-e156.]. PMID:25760500

Adams, John D; Tanner, Stephanie L; Jeray, Kyle J

2015-03-01

144

Orthogonal femoral plating  

PubMed Central

Objectives This study tests the biomechanical properties of adjacent locked plate constructs in a femur model using Sawbones. Previous studies have described biomechanical behaviour related to inter-device distances. We hypothesise that a smaller lateral inter-plate distance will result in a biomechanically stronger construct, and that addition of an anterior plate will increase the overall strength of the construct. Methods Sawbones were plated laterally with two large-fragment locking compression plates with inter-plate distances of 10 mm or 1 mm. Small-fragment locking compression plates of 7-hole, 9-hole, and 11-hole sizes were placed anteriorly to span the inter-plate distance. Four-point bend loading was applied, and the moment required to displace the constructs by 10 mm was recorded. Results We found that a 1 mm inter-plate distance supported greater moments than a 10 mm distance in constructs with only lateral plates. Moments supported after the addition of a 9- or 11-hole anterior plate were greater for both 10 mm and 1 mm inter-plate distance, with the 11-hole anterior plate supporting a greater moment than a 9-hole plate. Femurs with a 7-hole anterior plate fractured regardless of lateral inter-plate distance size. Conclusion This suggests that the optimal plate configuration is to minimise lateral inter-plate distance and protect it with an anterior plate longer than seven holes. Cite this article: Bone Joint Res 2015;4:23–8. PMID:25715873

Auston, D. A.; Werner, F. W.; Simpson, R. B.

2015-01-01

145

Locking hinge  

NASA Technical Reports Server (NTRS)

The space station configuration currently studied utilizes structures which require struts to be hinged in the middle in the stowed mode and locked into place in the deployed mode. Since there are hundreds of hinges involved, it is necessary that they have simple, positive locking features with a minimum of joint looseness or slack. This invention comprises two similar housings hinged together with a spring loaded locking member which assists in making as well as breaking the lock. This invention comprises a bracket hinge and bracket members with a spring biased and movable locking member. The locking or latch member has ear parts received in locking openings where wedging surfaces on the ear parts cooperate with complimentary surfaces on the bracket members for bringing the bracket members into a tight end-to-end alignment when the bracket members are in an extended position. When the locking member is moved to an unlocking position, pivoting of the hinge about a pivot pin automatically places the locking member to retain the locking member in an unlocked position. In pivoting the hinge from an extended position to a folded position, longitudinal spring members are placed under tension over annular rollers so that the spring tension in a folded position assists in return of the hinge from a folded to an extended position. Novelty lies in the creation of a locking hinge which allows compact storage and easy assembly of structural members having a minimal number of parts.

Wesselski, Clarence J. (inventor)

1988-01-01

146

Mechanical performance of the standard Orthofix external fixator.  

PubMed

Static and fatigue tests of the standard Orthofix unilateral external fixator (Orthofix SRL, Verona, Italy) were performed. Under similar fixation configurations, the Orthofix device offered higher bending stiffness in both directions, equal torsional stiffness, and lower axial stiffness when compared to the Hoffmann-Vidal quadrilateral frame with full pins. The bending resistance of the Orthofix ball joint was found to be proportional to its locking cam tightening torque. After applying 2 million loading cycles to the bone ends fixed by the device, the overall stiffness characteristics of the frame did not change significantly. Repetitive manual tightening and loosening of the ball joint caused abrasive wear on the cam and bushing surfaces. The locking position of the cam migrated for a mean of 45 degrees. After 50 cycles of tightening and bending to failure, the ball joint locking strength was reduced by 20% to 25%, but the stiffness did not change. Wear and stripping of the seat of the fixator body locking screw and the pin fixation screw threads were also noted. Based on the test results, the standard Orthofix device could be re-used, but certain fixator components must be inspected and replaced. The ball joint locking cam and fixation screws required periodic tightening during clinical application to prevent loss of frame stiffness under repetitive loading. Modifications of the fixator design are recommended to improve its mechanical performance. PMID:3405906

Chao, E Y; Hein, T J

1988-07-01

147

Locking mechanism  

DOEpatents

The invention is a motorized linkage for operating a door strike. A six volt power source, controlled by a security code, rotates a small electric motor when a proper security code is given. The motor rotates a shaft which engages a coil spring. This moves a locking cam. When a catch on the locking cam separates from the locking lever catch, the latch bolt keeper may be manipulated by a user.

Williams, Gary L. (428 E. Third Avenue, Kennewick, WA 99336); Goin, Jr., Jesse L. (480 Kau Trail, Pasco, WA 99301); Kirby, Patrick G. (1010 W. Fifteenth Pl., Kennewick, WA 99337); McKenna, John P. (Rt. 3, Box 1818, Benton City, WA 99320)

1997-01-01

148

A new adhesive technique for internal fixation in midfacial surgery  

Microsoft Academic Search

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

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

2008-01-01

149

Titanium plate artefact mimicking popliteal artery dissection on digital subtraction CT angiography  

PubMed Central

Titanium plates used for the internal fixation of long bone fractures cause significant artefact on CT scans but have not been reported to affect digital subtraction CT angiography. We present a patient with clinical suspicion of popliteal artery injury following a high tibial osteotomy. The osteotomy was stabilised with a titanium locking plate. During the digital subtraction process used to produce reconstruction CT angiography, removal of artefact caused by the titanium plate produced CT images mimicking the appearance of a popliteal artery dissection. The imaging inaccuracy was realised prior to the patient undergoing further intervention. We highlight the potential error caused by titanium plates on digital subtraction CT angiography and recommend careful analysis of such images prior to further treatment. PMID:23563677

Woodacre, Timothy; Wienand-Barnett, Sophie

2013-01-01

150

Development and mechanical testing of a short intramedullary nail for fixation of femoral rotational osteotomy in cerebral palsy patients  

PubMed Central

Background Rotational osteotomy is frequently indicated to correct excessive femoral anteversion in cerebral palsy patients. Angled blade plate is the standard fixation device used when performed in the proximal femur, but extensile exposure is required for plate accommodation. The authors developed a short locked intramedullary nail to be applied percutaneously in the fixation of femoral rotational osteotomies in children with cerebral palsy and evaluated its mechanical properties. Methods The study was divided into three stages. In the first part, a prototype was designed and made based on radiographic measurements of the femoral medullary canal of ten-year-old patients. In the second, synthetic femoral models based on rapid-prototyping of 3D reconstructed images of patients with cerebral palsy were obtained and were employed to adjust the nail prototype to the morphological changes observed in this disease. In the third, rotational osteotomies were simulated using synthetic femoral models stabilized by the nail and by the AO-ASIF fixed-angle blade plate. Mechanical testing was done comparing both devices in bending-compression and torsion. Results The authors observed proper adaptation of the nail to normal and morphologically altered femoral models, and during the simulated osteotomies. Stiffness in bending-compression was significantly higher in the group fixed by the plate (388.97 ± 57.25 N/mm) than in that fixed by the nail (268.26 ± 38.51 N/mm) as torsional relative stiffness was significantly higher in the group fixed by the plate (1.07 ± 0.36 Nm/°) than by the nail (0.35 ± 0.13 Nm/°). Conclusions Although the device presented adequate design and dimension to fit into the pediatric femur, mechanical tests indicated that the nail was less stable than the blade plate in bending-compression and torsion. This may be a beneficial property, and it can be attributed to the more flexible fixation found in intramedullary devices. PMID:21711560

2011-01-01

151

49 CFR 236.779 - Plate, top.  

Code of Federal Regulations, 2010 CFR

... 2010-10-01 2010-10-01 false Plate, top. 236.779 Section 236.779 Transportation...AND APPLIANCES Definitions § 236.779 Plate, top. A metal plate secured to a locking bracket to prevent the cross locking from...

2010-10-01

152

Tectonic Plates and Plate Boundaries  

NSDL National Science Digital Library

Continents were once thought to be static, locked tight in their positions in Earth's crust. Similarities between distant coastlines, such as those on opposite sides of the Atlantic, were thought to be the work of a scientist's overactive imagination, or, if real, the result of erosion on a massive scale. This interactive feature shows 11 tectonic plates and their names, the continents that occupy them, and the types of boundaries between them.

153

12. VIEW OF TYPICAL CELL LOCKING MECHANISM, BUILDING 220 CELL ...  

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

12. VIEW OF TYPICAL CELL LOCKING MECHANISM, BUILDING 220 CELL BLOCK 'A'. THE FACE PLATE OF THE CELL LOCK IS SHOWN REMOVED, EXPOSING THE ELECTROMAGNETIC LOCKING MECHANISM COMPRISING OF 2 MICROSWITCHES FOR LOCK POSITION INDICATION (FRONT LEFT CENTER AND REAR RIGHT CENTER OF PANEL); KEY SLOT MECHANICAL LOCK; LOCK SPRING (UPPER RIGHT OF PANEL); ELECTRIC SOLENOID (BOTTOM RIGHT CORNER OF PANEL); AND MISCELLANEOUS MECHANICAL LINKAGES. - U.S. Naval Base, Pearl Harbor, Brig, Neville Way near Ninth Street at Marine Barracks, Pearl City, Honolulu County, HI

154

Limb lengthening over plate  

PubMed Central

Background: The limb lengthening over plate eliminates the associated risk of infection with limb lengthening over intramedullary nail. We present our experience of limb lengthening in 15 patients with a plate fixed on the proximal segment, followed by corticotomy and application of external fixator. Materials and Methods: 15 patients (7 females, 8 males) were included in this consecutive series. The average age was 18.1 years (range 8–35 years). Fifteen tibiae and one femur were lengthened in 15 patients. Lengthening was achieved at 1 mm/day followed by distal segment fixation with three or four screws on reaching the target length. Results: The preoperative target length was successfully achieved in all patients at a mean of 4.1 cm (range 1.8–6.5 cm). The mean duration of external fixation was 75.3 days (range 33–116 days) with the mean external fixation index at 19.2 days/cm (range 10.0–38.3 days/cm). One patient suffered deep infection up to the plate, three patients had mild procurvatum deformities, and one patient developed mild tendo achilles contracture. Conclusion: Lengthening over a plate allows early removal of external fixator and eliminates the risk of creating deep intramedullary infection as with lengthening over nail. Lengthening over plate is also applicable to children with open physis. PMID:22719123

Kulkarni, Ruta; Singh, Nishant; Kulkarni, Govind S; Kulkarni, Milind; Kulkarni, Sunil; Kulkarni, Vidisha

2012-01-01

155

Automatic locking orthotic knee device  

NASA Technical Reports Server (NTRS)

An articulated tang in clevis joint for incorporation in newly manufactured conventional strap-on orthotic knee devices or for replacing such joints in conventional strap-on orthotic knee devices is discussed. The instant tang in clevis joint allows the user the freedom to extend and bend the knee normally when no load (weight) is applied to the knee and to automatically lock the knee when the user transfers weight to the knee, thus preventing a damaged knee from bending uncontrollably when weight is applied to the knee. The tang in clevis joint of the present invention includes first and second clevis plates, a tang assembly and a spacer plate secured between the clevis plates. Each clevis plate includes a bevelled serrated upper section. A bevelled shoe is secured to the tank in close proximity to the bevelled serrated upper section of the clevis plates. A coiled spring mounted within an oblong bore of the tang normally urges the shoes secured to the tang out of engagement with the serrated upper section of each clevic plate to allow rotation of the tang relative to the clevis plate. When weight is applied to the joint, the load compresses the coiled spring, the serrations on each clevis plate dig into the bevelled shoes secured to the tang to prevent relative movement between the tang and clevis plates. A shoulder is provided on the tang and the spacer plate to prevent overextension of the joint.

Weddendorf, Bruce C. (inventor)

1993-01-01

156

Biomechanical evaluation of interfragmentary compression at tibia plateau fractures in vitro using different fixation techniques: a CONSORT-compliant article.  

PubMed

Reliable osteosynthesis of intraarticular fractures depends on lasting interfragmentary compression. Its amount differs in the applied fixation method. The interfragmentary compression of cancellous and cortical lag screws and angle stable locking plates was quantified in an osteoporotic and non-osteoporotic synthetic human bone model.A split fracture of the lateral tibia plateau (AO/OTA type 41-B1.1) was mimicked by an osteotomy in right adult synthetic human tibiae with hard or soft cancellous bone. Specimens were fixed with either two 6.5?mm cancellous, four 3.5?mm cortical lag screws, or 3.5?mm LCP proximal lateral tibia plate preliminary compresed by a reduction clamp (n?=?5 per group). A pressure sensor film was used to register the interfragmentary compression. One-way analysis of variance (ANOVA) with Bonferroni post hoc correction was performed for statistical analysis (p?locking plate itself maintained the compression in non-osteoporotic (0.53?±?0.11?MPa) and osteoporotic bone (0.50?±?0.14?MPa). Four 3.5?mm cortical lag screws provided a compression of 1.69?±?0.65?MPa in non-osteoporotic bone, being not significantly different to the osteoporotic bone group (1.43?±?0.47?MPa, P?=?1.0). Two 6.5?mm cancellous lag screws showed a significantly higher compression in non-osteoporotic (2.1?±?0.59?MPa) compared to osteoporotic (0.77?±?0.21?MPa, P?locking plates maintained the compression preliminarily applied by a reduction clamp. Two 6.5?mm cancellous lag screws are especially suited for non-osteoporotic bone, whereas four 3.5?mm cortical screws exhibited comparable compression in both bone qualities. PMID:25569643

Kojima, K; Gueorguiev, B; Seva, G; Stoffel, K; de Oliveira, R Garcia; Eberli, U; Nicolino, T; Lenz, M

2015-01-01

157

Biomechanical evaluation of maxillary Lefort ? fracture with bioabsorbable osteosynthesis internal fixation.  

PubMed

The aim of this study was to apply biomechanical analysis model to evaluate the effects of bioabsorbable internal fixation devices on maxillary Lefort ? fracture. CT scan technology and the finite element software (ansys) were used to establish three-dimensional finite element models of five resorbable internal fixation devices in maxillary Lefort ? fractures. We used the model to calculate the stress of the upper jaw and internal fixation. We further analyzed the stability of fixation under four occlusions. The fixation using two bioabsorbable plates was not stable. The zygomaticomaxillary pillars fixation is more stable than other fixations. The stability of fracture fixation was influenced with the molar occlusion. The current study developed a functional three-dimensional finite element model of bioabsorbable internal fixation and compared the stability of five fixation methods for maxillary Lefort ? fractures. The results would facilitate the application of bioabsorbable materials in dental clinic. PMID:25146129

Wu, Wei; Zhou, Jiang; Xu, Chong-Tao; Zhang, Jie; Jin, Yan-Jiao; Sun, Geng-Lin

2014-12-01

158

Safety lock-out device for electrical appliances  

DOEpatents

A safety lock-out device prevents the insertion of an electrical power cord into an electrical power cord receptacle of an electrical appliance. The device comprises a mounting plate fastened to the appliance and a hinged cover plate attached to the appliance. The cover plate is movable between a first position and a second position such that, in the first position, the cover plate covers and prevents insertion of a power cord into the appliance receptacle. In said second position, the appliance receptacle is uncovered to permit insertion of a power cord into the receptacle. Extending a lock shank through aligned openings formed in flange members extending from the mounting plate, the cover plate locks the cover plate in the first position. 15 figs.

Cliff, P.L. Jr.

1996-07-09

159

Open reduction technique for overlapping and locked pubic symphysis.  

PubMed

A locked pubic symphysis can occur following a lateral compression injury of the pelvic ring when one pubic bone becomes entrapped behind the contralateral pubis or obturator foramen. In selecting the treatment modality, it is important to know the mechanism of injury. We presented the use of an open reduction technique in the treatment of a locked pubic symphysis in which open reduction external fixation application failed in the emergency department. PMID:22441457

Botanlio?lu, Hüseyin; Bilsel, Nafiz; Kaynak, Gökhan; Unlü, Mehmet Can

2012-01-01

160

Fixation of an ulnodorsal fragment when treating an intra-articular fracture in the distal radius.  

PubMed

If fixation of an ulnodorsal fragment in an intra-articular fracture of the distal radius is not stable, it is sometimes caused by dorsal displacement after surgery. Hence, we recommend the volar plate fixation with an additional dorsal approach and fixation of irreducible ulnodorsal fragments using a low-profile dorsal mini plate. The details of the surgical procedure and indications are discussed in this article. PMID:24641759

Ikeda, Kazuo; Osamura, Naoki; Tada, Kaoru

2014-01-01

161

Hybrid Fixation of Tibial Eminence Fractures in Skeletally Immature Patients  

PubMed Central

Tibial eminence fractures most commonly occur in children and adolescents. When treating displaced fractures of the tibial eminence, some surgeons prefer screw fixation whereas others prefer suture fixation. The ultimate goal is to limit morbidity through early return to range of motion and activity. In this technical note, we describe 2 hybrid fixation techniques for fixing tibial eminence fractures, one for type III and the other for type IV fractures. The first technique (variation A) is used to treat type III fractures and combines use of both a bioabsorbable compression screw and suture for fixation. The second technique (variation B) is used to treat type IV fractures and combines use of both a bioabsorbable compression screw and shoulder anchor fixation. We have found that these methods provide efficient, secure, and reliable fixation using standard techniques common to arthroscopic surgery. In addition, the growth plates are spared in children and adolescents, and the need for reoperation to remove hardware is eliminated. PMID:24265991

Gans, Itai; Babatunde, Oladapo M.; Ganley, Theodore J.

2013-01-01

162

Design of an occipito-cervical fixation device.  

PubMed

Metal plates may be used to stabilize the cervical spine. The plates are attached to the posterior of the vertebra by placing screws into the lateral masses. The plating may be extended, in the form of rod or plate, to connect with and support the occiput. Several problems, such as screw loosening and the plate obscuring the surgeon's view as a screw is being inserted, have been identified with present plate systems. This paper describes the initial design for a cervical fixation device to overcome these problems, and the design and development that was undertaken to enable a prototype device to be manufactured. PMID:10997060

Shepherd, D E; Bolger, C M; Leahy, J C; Mathias, K J; Hukins, D W

2000-01-01

163

Predicting preference from fixations  

Microsoft Academic Search

We measured the strength of the association between looking behaviour and preference. Participants selected the most preferred face out of a grid of 8 faces. Fixation times were correlated with selection on a trial-by-trial basis, as well as with explicit preference ratings. Furthermore, by ranking features based on fixation times, we were able to successfully predict participants' preferences for novel

Mackenzie G. Glaholt; Mei-chun Wu; Eyal M. Reingold

2009-01-01

164

Fixation: A Bibliography.  

ERIC Educational Resources Information Center

Fixation and regression were considered complementary by Freud. You tend to regress to a point of fixation. They are both opposed to progression. In the general area, Anna Freud has written (The Ego and the Mechanisms of Defence. London: Hogarth and the Psycho-Analytic Institute, 1937), Sears has evaluated (Survey of Objective Studies of…

Pedrini, D. T.; Pedrini, Bonnie C.

165

Minimal locked trees  

E-print Network

Locked tree linkages have been known to exist in the plane since 1998, but it is still open whether they have a polynomial-time characterization. This paper examines the properties needed for planar trees to lock, with a ...

Ballinger, Brad

166

Anterior subcutaneous internal fixation for treatment of unstable pelvic fractures  

PubMed Central

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

2014-01-01

167

Fast flux locked loop  

DOEpatents

A flux locked loop for providing an electrical feedback signal, the flux locked loop employing radio-frequency components and technology to extend the flux modulation frequency and tracking loop bandwidth. The flux locked loop of the present invention has particularly useful application in read-out electronics for DC SQUID magnetic measurement systems, in which case the electrical signal output by the flux locked loop represents an unknown magnetic flux applied to the DC SQUID.

Ganther, Jr., Kenneth R. (Olathe, KS); Snapp, Lowell D. (Independence, MO)

2002-09-10

168

Overview of locking systems  

SciTech Connect

The purpose of this document is to present technical information that should be useful for understanding and applying locking systems for physical protection and control. There are major sections on hardware for locks, vaults, safes, and security containers. Other topics include management of lock systems and safety considerations. This document also contains notes on standards and specifications and a glossary.

Gee, K.T.; Scott, S.H.; Wilde, M.G. [Sandia National Labs., Albuquerque, NM (United States); Highland, S.E. [Albuquerque Safe Co., Albuquerque, NM (United States)

1993-12-01

169

Lock For Valve Stem  

NASA Technical Reports Server (NTRS)

Simple, cheap device locks valve stem so its setting cannot be changed by unauthorized people. Device covers valve stem; cover locked in place with standard padlock. Valve lock made of PVC pipe and packing band. Shears, drill or punch, and forming rod only tools needed.

Burley, Richard K.; Guirguis, Kamal S.

1991-01-01

170

Multidimensional Sternal Fixation to Overcome a “Floating” Sternum  

PubMed Central

This case report describes the repair of a complete sternal dehiscence of the lower right sternum using sternal wires, manubrial plates, and a Talon closure device for rigid, multidimensional sternal fixation. Sternal dehiscence is a rare but significant cause of morbidity for patients undergoing median sternotomy. The risk factors for this complication are well described and although sternal wires have traditionally been used for primary closure, rigid fixation with sternal plates is a viable alternative to avoid dehiscence in this high-risk cohort. PMID:25379318

Rothstein, William; Spata, Tyler

2014-01-01

171

Orthodontic skeletal anchorage using a palatal external plate.  

PubMed

We have developed the Anchor-Lock external plate system, which is fitted on the palate for the purpose of orthodontic skeletal anchorage. The aim of this study was to introduce the Anchor-Lock and assess its success rate. The Anchor-Lock is composed of titanium screws of 2·0-mm diameter and a titanium plate of 1·0-mm thickness. The external plate is rigidly interlocked with the heads of the screws, which are implanted trans-mucosally into palatal bone. Three types of Anchor-Lock are available. These were applied to 137 orthodontic patients (104 females and 33 males) aged 10-54 years. Two types of plate were used, a straight-shaped plate applied to the hard palate and to the anterior palate and a double-Y-shaped plate applied after tooth-borne rapid maxillary expansion. Success rate of the Anchor-Lock was 92·0% overall. No significant difference in success rate was found by age or sex of patients. Type or screw length of the Anchor-Lock did not affect success rate significantly. Success rate was significantly increased by the use of the surgical stent. The Anchor-Lock was effectively applied to distalize and/or intrude the upper molars. The Anchor-Lock system appears suitable for clinical use as an alternative to conventional screw- and plate-type orthodontic implants. PMID:24671290

Kobayashi, Masaru; Fushima, Kenji

2014-03-01

172

Measuring electrical resistivity to interpret tectonic plate coupling  

NASA Astrophysics Data System (ADS)

The coupling of tectonic plates—the degree to which the plates are locked together or free to move—is controlled by factors ranging from temperature and pressure to the shear stress between the plates as well as the shape of the interface between the plates. At subduction margins, GPS observations can be used to identify places where the subducting plates are locked or unlocked. At the Hikurangi margin, a subduction zone that runs north to south off New Zealand's eastern coast, a strong longitudinal gradient in plate coupling is present that is unexplained by any of the familiar factors.

Schultz, Colin

2013-12-01

173

Adapter plate assembly for adjustable mounting of objects  

DOEpatents

An adapter plate and two locking discs are together affixed to an optic table with machine screws or bolts threaded into a fixed array of internally threaded holes provided in the table surface. The adapter plate preferably has two, and preferably parallel, elongated locating slots each freely receiving a portion of one of the locking discs for secure affixation of the adapter plate to the optic table. A plurality of threaded apertures provided in the adapter plate are available to attach optical mounts or other devices onto the adapter plate in an orientation not limited by the disposition of the array of threaded holes in the table surface. An axially aligned but radially offset hole through each locking disc receives a screw that tightens onto the table, such that prior to tightening of the screw the locking disc may rotate and translate within each locating slot of the adapter plate for maximum flexibility of the orientation thereof.

Blackburn, R.S.

1986-05-02

174

How A Lock Works  

NSDL National Science Digital Library

Ships travelling between Lake Ontario and Lake Erie use the Welland Canal. Beginning with a conversation between characters Mathise, Geo, and Trig, they explain how a lock in the canal operates by gravity alone, without pumps. The characters use mathematics to solve problems such as how long the locks take to fill and how to express the volume and flow of water in more common terms (bathtubs of water per second). They also ask why the lower lock door is much larger and heavier than the upper one, a question which users can answer by watching the animation of the lock's operation.

175

West Branch Pennsylvania Canal, Lock No. 34 Lock Keeper's House, ...  

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

West Branch Pennsylvania Canal, Lock No. 34 Lock Keeper's House, South of State Route 664 along North bank of West Branch of Susquehanna River, 2,000 feet East of Jay Street Bridge, Lock Haven, Clinton County, PA

176

EXTERIOR VIEW OF LOWER LOCK GATES CLOSED. FROM LOCK WALL, ...  

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

EXTERIOR VIEW OF LOWER LOCK GATES CLOSED. FROM LOCK WALL, LOOKING NORTH NORTHWEST. - Illinois Waterway, La Grange Lock and Dam, 3/4 mile south of Country 795N at Illinois River, Versailles, Brown County, IL

177

Biomechanical Study of Acetabular Tridimensional Memoryalloy Fixation System  

NASA Astrophysics Data System (ADS)

We developed the acetabular tridimensional memoryalloy fixation system (ATMFS), which is made of NiTi shape memory alloy, according to the specific mechanical properties of biological memory material, NiTi shape memory alloy and measured distribution of contact area and pressure between the acetabulum and the femoral head of cadaveric pelvis. Seven formalin-preserved cadaveric pelves were used for this investigation. Pressure-sensitive film was used to measure contact area and pressure within the anterior, superior, and posterior regions of the acetabulum. The pelves were loaded under the following four conditions: (1) intact; (2) following a creation posterior wall fracture defect; (3) following reduction and standard internal fixation with reconstruction plate; and (4) following reduction and internal fixation with a new shape memory alloy device named ATMFS. A posterior wall fracture was created along an arc of 40° to 90° about the acetabulur rim. Creation of a posterior wall defect resulted in increased load in the superior acetabulum (1485 N) as compared to the intact condition (748 N, P = 0.009). Following reduction and internal fixation, the load distributed to the superior acetabulum (1545 N) was not statistically different from the defect condition. Following the fixation with ATMFS, the load seen at the superior region of the actabulum (964 N) was familiar with fixation with reconstruction plate and was not different from intact state ( P = 0.45). These data indicate that the use of ATMFS as a fracture internal fixation device resulted a partial restoration of joint loading parameters toward the intact state. ATMFS fixation may result in a clinical benefit.

Liu, Xin-Wei; Xu, Shuo-Gui; Zhang, Yun-Tong; Zhang, Chun-Cai

2011-07-01

178

Pessimistic Software Lock-Elision  

E-print Network

Read-write locks are one of the most prevalent lock forms in concurrent applications because they allow read accesses to locked code to proceed in parallel. However, they do not offer any parallelism between reads and ...

Afek, Yehuda

2012-01-01

179

Tacks: a new technique for craniofacial fixation.  

PubMed

Biodegradable fixation in craniofacial surgery provides secure fixation while eliminating much of the concern over intracranial migration of metallic plates and screws. One limitation of present biodegradable systems, however, is the need for tapping the drill hole before screw insertion. Herein, a new method of rigid, biodegradable fixation with tacks (Macrapore, Inc., San Diego, CA) is described. The tacks are made of a 70:30 ratio of the L and DL form of polylactic acid (L,DL-PLA). Degradation times range from 18 to 36 months. Newer prototypes are nearly developed for more rapid dissolution times. From April 1999 to February 2000, tack fixation has been applied in 100 patients (51 males, 49 females aged 3 months to 61 years). Indications for operation were craniosynostosis (n = 33); craniofacial trauma or post-traumatic deformities (n = 11); cleft lip and palate (n = 13); craniofacial syndromes (n = 18); other diagnoses (n = 11). Patients underwent fronto-orbital advancement with cranial reshaping; monobloc osteotomy, open reduction-internal fixation of fractures; hypertelorbitism repair; cranioplasty; stabilization of grafts; major cranial reconstruction; zygomatic advancement; alveolar cleft repair; and iliac bone graft donor site protection. Tacks were also used for temporalis muscle and lateral canthal suspension. Follow-up ranged from 16 to 28 months. Complications occurred in 7 patients, 4 of whom had infections and during debridement had biodegradable implants removed. None of the complications appeared to be related to the use of tacks. The tacks are carried in a specially designed holder and may be placed by hand or with the light tap of a mallet on the tack driver. An automatic driver has been developed. Overall, the performance of the tacks has been excellent. They are easily handled by the nursing personnel and rapidly inserted by the surgeon. Stability appears to be excellent. At this time, it is probably preferable to employ tap and screws for orthognathic surgery or other osteotomies with substantial load bearing. PMID:11711829

Cohen, S R; Holmes, R E; Amis, P; Fitchner, H; Shusterman, E M

2001-11-01

180

Rotatable stem and lock  

DOEpatents

A valve stem and lock include a housing surrounding a valve stem, a solenoid affixed to an interior wall of the housing, an armature affixed to the valve stem and a locking device for coupling the armature to the housing body. When the solenoid is energized, the solenoid moves away from the housing body, permitting rotation of the valve stem.

Deveney, Joseph E. (Albuquerque, NM); Sanderson, Stephen N. (Albuquerque, NM)

1984-01-01

181

Rotatable stem and lock  

DOEpatents

A valve stem and lock is disclosed which includes a housing surrounding a valve stem, a solenoid affixed to an interior wall of the housing, an armature affixed to the valve stem and a locking device for coupling the armature to the housing body. When the solenoid is energized, the solenoid moves away from the housing body, permitting rotation of the valve stem.

Deveney, J.E.; Sanderson, S.N.

1981-10-27

182

Adjustable locking device  

NASA Technical Reports Server (NTRS)

Adjustable locking device is used for taking up end play of shaft without displacing shaft radially. Coincidentally threaded collars fastened to one or both ends of shaft are threaded in and out of one another for adjustment of end play. Intrinsic feature is its ability to be locked in any translatory position without axial displacement of shaft.

Fincannon, O. J.

1972-01-01

183

Quick-Change Anode for Plating  

NASA Technical Reports Server (NTRS)

Proposed fastener for attaching electroplating anode improves quality of plating and increases productivity. Notches in twist-lock fastener mates with projections on end of anode bar. Fastener made of titanium for compatibility with copper-plating solution. Also constructed in snap-on, snap-off configuration.

Beasley, J. L.

1987-01-01

184

The Fixation of Nitrogen.  

ERIC Educational Resources Information Center

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)

Andrew, S. P. S.

1978-01-01

185

Update: Biological Nitrogen Fixation.  

ERIC Educational Resources Information Center

Updates knowledge on nitrogen fixation, indicating that investigation of free-living nitrogen-fixing organisms is proving useful in understanding bacterial partners and is expected to lead to development of more effective symbioses. Specific areas considered include biochemistry/genetics, synthesis control, proteins and enzymes, symbiotic systems,…

Wiseman, Alan; And Others

1985-01-01

186

Outcomes After Fixation of Proximal Humerus (OTA Type 11) Fractures in the Elderly Patients Using Modern Techniques  

PubMed Central

Purpose To investigate the effects of age on the clinical, functional, and radiographic outcomes of patients with proximal humerus fractures treated operatively with locking plates. Methods Between February 2003 and July 2012, all patients who sustained a proximal humerus fracture who presented to our institution were enrolled into a database. Patients were followed up at 1, 6, 12, 26, and 52 weeks postoperatively with physical examination and radiographs. Validated functional outcomes scores were collected at 6 and 12 months. Complications were recorded as they occurred. Statistical analysis was conducted to assess for functional, physical, or radiographic differences between patients age younger than 65 and patients age 65 or older. Results Of the 147 consecutive patients treated operatively for a proximal humerus fracture, 115 (78%) patients with an average follow-up of 16 months met the inclusion criteria for this study. The young cohort (patients < 65) included 70 patients with an average age of 53, whereas the elderly cohort (patients ? 65) included 45 patients with an average age of 73. The older cohort had significantly more women (P = .04), but there was no statistical difference in fracture type between the age groups. There were no differences in the radiographic measures of screw penetration, humeral head height, and neck-shaft angle between the age groups. There were no differences in physical examination scores between the age groups. There were no significant differences in functional outcomes or complication rates between the age groups. Conclusion Treating proximal humerus fractures operatively with locked plates can overcome the challenges of poor bone quality that often occur with increasing age. Age should not play a significant role in the decision-making process for treating proximal humerus fractures that would otherwise be indicated for surgical fixation. PMID:23936736

Shulman, Brandon S.; Ong, Crispin C.; Lee, James H.; Karia, Raj; Zuckerman, Joseph D.; Egol, Kenneth A.

2013-01-01

187

Plate TectonicsPlate Tectonics Plate TectonicsPlate Tectonics  

E-print Network

Plate TectonicsPlate Tectonics #12;Plate TectonicsPlate Tectonics · Lithosphere ­ strong, rigid, transform boundaries ­ travel 1 to 11 cm/yr relative to one another #12;14 tectonic plates today #12;Mid asthenosphere that flows · 8 large lithospheric plates and 6 smaller ones ­ separated by divergent, convergent

Siebel, Wolfgang

188

The Mechanics of External Fixation  

PubMed Central

External fixation has evolved from being used primarily as a last resort fixation method to becoming a main stream technique used to treat a myriad of bone and soft tissue pathologies. Techniques in limb reconstruction continue to advance largely as a result of the use of these external devices. A thorough understanding of the biomechanical principles of external fixation is useful for all orthopedic surgeons as most will have to occasionally mount a fixator throughout their career. In this review, various types of external fixators and their common clinical applications are described with a focus on unilateral and circular frames. The biomechanical principles that govern bony and fixator stability are reviewed as well as the recommended techniques for applying external fixators to maximize stability. Additionally, we have illustrated methods for managing patients while they are in the external frames to facilitate function and shorten treatment duration. PMID:18751766

Rozbruch, S. Robert

2006-01-01

189

Electronic door locking mechanism  

DOEpatents

The invention is a motorized linkage for engaging a thumb piece in a door mechanism. The device has an exterior lock assembly with a small battery cell and combination lock. Proper entry by a user of a security code allows the battery to operate a small motor within the exterior lock assembly. The small motor manipulates a cam-plunger which moves an actuator pin into a thumb piece. The user applies a force on to the thumb piece. This force is transmitted by the thumb piece to a latch engagement mechanism by the actuator pin. The latch engagement mechanism operates the door latch.

Williams, Gary Lin (428 E. Third Ave., Kennewick, WA 99336); Kirby, Patrick Gerald (1010 W. Fifteenth Pl., Kennewick, WA 99337)

1997-01-01

190

Electronic door locking mechanism  

DOEpatents

The invention is a motorized linkage for engaging a thumb piece in a door mechanism. The device has an exterior lock assembly with a small battery cell and combination lock. Proper entry by a user of a security code allows the battery to operate a small motor within the exterior lock assembly. The small motor manipulates a cam-plunger which moves an actuator pin into a thumb piece. The user applies a force on to the thumb piece. This force is transmitted by the thumb piece to a latch engagement mechanism by the actuator pin. The latch engagement mechanism operates the door latch. 6 figs.

Williams, G.L.; Kirby, P.G.

1997-10-21

191

Distal radius fixation through a mini-invasive approach of 15 mm. PART 1: a series of 144 cases.  

PubMed

The volar Henry approach is becoming the gold standard for distal radius fracture fixation. It decreases the incidence of nonunion, limits complications especially complex regional pain syndrome (CRPS) type I, and allows early mobilization of the wrist. Nonetheless, it has some disadvantages such as the size of the incision, which is not esthetically pleasing, and the loss of ligamentotaxis. This is why some authors have developed a mini-invasive approach. The aim of this work was to evaluate the feasibility of the anterior mini-invasive approach of 15 mm in a clinical series of 144 cases of distal radius fracture. All patients were operated under regional anesthesia using the same techniques by five surgeons of the same team. According to the AO classification, there were 83 type A fractures, 2 type B, and 59 type C. A volar plate (Step One(®), Newclip Technics™, Haute-Goulaine, France) was used in all cases. The 2 proximal metaphyseal screws and the 2 distal central epiphyseal screws were monoaxial locking. The 2 distal ulnar and radial epiphyseal screws were placed in polyaxial locking at 20° angulation maximum. Skin closure without drainage was performed. No postoperative immobilization was prescribed, and patients were encouraged to use their upper limb immediately postoperative. No postoperative physiotherapy was prescribed. The mean follow-up was 4.1 months. The final size of the incision was on average 16.1 mm. Mean pain score was 1.8. The Quick DASH score was average 25. Average range of motion was more than 85 %, and global force of the hand was 67 % compared with contralateral side. On X-ray, the mean radial slope was 22°, the mean radial tilt was 8.3°, and the mean radioulnar variance/index was -0.4 mm. There were nine cases of CRPS type I, which all resolved. Specific complications included two secondary displacements and nine tenosynovitis cases. No tendon rupture was noted. Two intra-articular distal radioulnar joint screws had to be removed at 3 months. One epiphyseal screw required removal 1 month postoperative due to loosening. There were no intra-articular radiocarpal screws. Distal radius fracture fixation using a mini-invasive approach is a reliable and reproducible procedure with few complications. It allows anatomical reduction in the distal radius fractures including intra-articular ones. It can be associated with arthroscopy, scaphoid screw fixation or even percutaneous pinning. Thus, most traumatic lesions of the wrist bony or soft tissue can be treated through this mini-invasive approach. PMID:24258689

Lebailly, Frédéric; Zemirline, Ahmed; Facca, Sybille; Gouzou, Stéphanie; Liverneaux, Philippe

2014-08-01

192

The variable finesse locking technique  

Microsoft Academic Search

Virgo is a power recycled Michelson interferometer, with 3 km long Fabry Perot cavities in the arms. The locking of the interferometer has been obtained with an original lock acquisition technique. The main idea is to lock the instrument away from its working point. Lock is obtained by misaligning the power recycling mirror and detuning the Michelson from the dark

F. Acernese; P. Amico; M. Al-Shourbagy; S. Aoudia; S. Avino; D. Babusci; G. Ballardin; R. Barillé; F. Barone; L. Barsotti; M. Barsuglia; F. Beauville; M. A. Bizouard; C. Boccara; F. Bondu; L. Bosi; C. Bradaschia; S. Braccini; A. Brillet; V. Brisson; L. Brocco; D. Buskulic; E. Calloni; E. Campagna; F. Cavalier; R. Cavalieri; G. Cella; E. Chassande-Mottin; C. Corda; A.-C. Clapson; F. Cleva; J.-P. Coulon; E. Cuoco; V. Dattilo; M. Davier; R. De Rosa; L. Di Fiore; A. Di Virgilio; B. Dujardin; A. Eleuteri; D. Enard; I. Ferrante; F. Fidecaro; I. Fiori; R. Flaminio; J.-D. Fournier; S. Frasca; F. Frasconi; A. Freise; L. Gammaitoni; A. Gennai; A. Giazotto; G. Giordano; L. Giordano; R. Gouaty; D. Grosjean; G. Guidi; S. Hebri; H. Heitmann; P. Hello; L. Holloway; S. Kreckelbergh; P. La Penna; V. Loriette; M. Loupias; G. Losurdo; J.-M. Mackowski; E. Majorana; C. N. Man; M. Mantovani; F. Marchesoni; F. Marion; J. Marque; F. Martelli; A. Masserot; M. Mazzoni; L. Milano; C. Moins; J. Moreau; N. Morgado; B. Mours; A. Pai; C. Palomba; F. Paoletti; S. Pardi; A. Pasqualetti; R. Passaquieti; D. Passuello; B. Perniola; F. Piergiovanni; L. Pinard; R. Poggiani; M. Punturo; P. Puppo; K. Qipiani; P. Rapagnani; V. Reita; A. Remillieux; F. Ricci; I. Ricciardi; P. Ruggi; G. Russo; S. Solimeno; A. Spallicci; R. Stanga; R. Taddei; D. Tombolato; M. Tonelli; A. Toncelli; E. Tournefier; F. Travasso; G. Vajente; D. Verkindt; F. Vetrano; A. Viceré; J.-Y. Vinet; H. Vocca; M. Yvert; Z. Zhang; M. Evans

2006-01-01

193

Novel posterior fixation keratoprosthesis  

NASA Astrophysics Data System (ADS)

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.

Lacombe, Emmanuel

1992-08-01

194

The Digital Locke Project  

NSDL National Science Digital Library

The influence of John Locke on human thought is hard to overstate, and scholars continue to mine his substantial corpus for insights into the ways that humans interact. This delightful website brings together a scholarly text edition of many of his works. The project is being overseen by Professor Paul Schuurman, and the database here includes multiple drafts of some of Locke's most powerful works, such as the seminal "An Essay Concerning Human Understanding." Visitors can get started by clicking on the "Texts" button to find the text of his works, along with an "About" area that gives some background material on each work. Those persons who might not be familiar with Locke might also appreciate the "About Locke" area of the site.

195

''Old'' locked inflation  

SciTech Connect

In this paper, we revisit the idea of locked inflation, which does not require a potential satisfying the normal slow-roll condition, but suffers from the problems associated with ''saddle inflation''. We propose a scenario based on locked inflation, however, with an alternative evolution mechanism of the ''waterfall field'' {phi}. Instead of rolling down along the potential, the {phi} field will tunnel to end the inflation stage like in old inflation, by which the saddle inflation could be avoided. Further, we study a cascade of old locked inflation, which can be motivated by the string landscape. Our model is based on the consideration of making locked inflation feasible so as to give a working model without slow roll; It also can be seen as an effort to embed the old inflation in string landscape.

Liu, Yang; Piao, Yun-Song [College of Physical Sciences, Graduate University of Chinese Academy of Sciences, Beijing 100049 (China)] [College of Physical Sciences, Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Si, Zong-Guo, E-mail: liuyangbyf@mail.sdu.edu.cn, E-mail: yspiao@gucas.ac.cn, E-mail: zgsi@sdu.edu.cn [Department of Physics, Shandong University, Jinan 250100 (China)] [Department of Physics, Shandong University, Jinan 250100 (China)

2009-05-15

196

CARBON DIOXIDE FIXATION.  

SciTech Connect

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.

FUJITA,E.

2000-01-12

197

The unstable iliac fracture: a biomechanical evaluation of internal fixation.  

PubMed

Neither plating nor lag screw fixation of a displaced iliac wing fracture as part of an unstable pelvic ring disruption has been studied biomechanically. The purpose of this study was to compare the stability of various combinations of fixation, specifically contrasting lag screws placed between the tables of the ilium with plating in different locations across the fracture line. Various combinations of these fixation implants were evaluated for an unstable iliac fracture. A longitudinal iliac fracture was created in each of six hemi-pelvic specimens prior to testing. Compressive force, up to 500 N or to the magnitude necessary to displace the fracture 2 mm, was applied to the fracture line through the hemi-pelvis for each of the plate and lag screw combinations tested. There was no statistical difference between any of the implants or combinations tested. A single 3.5-mm reconstruction (cephalad) plate placed along the cephalad internal aspect of the iliac crest provided the least stability allowing 2 mm of displacement with a mean load of 80 N. The two combinations of fixation that required the greatest loads for 2 mm of displacement were a single 3.5-mm lag (cephalad) screw inserted into the iliac crest between the tables of the ilium coupled with either a 3.5-mm reconstruction (brim) plate placed along the internal aspect of the inferior iliac fossa at the pelvic brim (239 N) or a 4.5-mm lag (brim) screw between the inner and outer tables at the inferior aspect of the fracture just above the greater sciatic notch (225 N). PMID:9509089

Simonian, P T; Routt, M L; Harrington, R M; Tencer, A F

1997-09-01

198

Absorbable biologically based internal fixation.  

PubMed

Absorbable devices for use in internal fixation have advanced over the years to become reliable and cost-effective alternatives to metallic hardware. In the past, biodegradable fixation involved a laborious implantation process, and induced osteolysis and inflammatory reactions. Modern iterations exhibit increased strength, smoother resorption, and lower rates of reactivity. A newer generation manufactured from silk has emerged that may address existing limitations and provide a greater range of fixation applications. PMID:25440418

Ibrahim, Ahmed M S; Koolen, Pieter G L; Kim, Kuylhee; Perrone, Gabe S; Kaplan, David L; Lin, Samuel J

2015-01-01

199

4. STONE BUILDER'S PLATE CANAL GATES, AND DIVERSION SPILLWAYS. ...  

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

4. STONE BUILDER'S PLATE CANAL GATES, AND DIVERSION SPILLWAYS. - Canal Road Bridge, Canal Road spanning Delaware Canal Diversion, Locks 22 & 23 in Delaware Canal State Park in Williams Township, Raubsville, Northampton County, PA

200

Definitive Bone Fixation and Reconstruction: Conversion from Temporary External Fixation to Internal Fixation Methods  

Microsoft Academic Search

\\u000a Temporary external fixation is frequently employed in the military combat theater of operations to temporize devastating extremity\\u000a injuries and facilitate transport of the wounded soldier. Multiple civilian and a few military studies have provided helpful\\u000a insight into the staged treatment of these injuries including conversion of temporary external fixation to definitive stabilization\\u000a with internal fixation. Diaphyseal fractures of the long

Craig S. Bartlett; Benjamin Geer; David L. Helfet

201

Plate Tectonics  

NSDL National Science Digital Library

The Plate Tectonics SciPack explores the various materials that make up Earth and the processes they undergo to provide a framework for understanding how continents are created and change over time. The focus is on Standards and Benchmarks related to Earth's layers, oceanic and continental plates and the interactions between plates.In addition to comprehensive inquiry-based learning materials tied to Science Education Standards and Benchmarks, the SciPack includes the following additional components:? Pedagogical Implications section addressing common misconceptions, teaching resources and strand maps linking grade band appropriate content to standards. ? Access to one-on-one support via e-mail to content "Wizards".? Final Assessment which can be used to certify mastery of the concepts.Learning Outcomes:Plate Tectonics: Layered Earth? Identify that Earth has layers (not necessarily name them), and that the interior is hotter and more dense than the crust.? Identify the crust as mechanically strong, and the underlying mantle as deformable and convecting.Plate Tectonics: Plates? Identify that the outermost layer of Earth is made up of separate plates.? Choose the correct speed of the motion of plates.? Identify the ocean floor as plate, in addition to the continents (to combat the common idea that only continents are plates, floating around on the oceans).? Recognize that oceans and continents can coexist on the same plate.Plate Tectonics: Plate Interactions? Identify the different interactions between plates.? Discuss what happens as a result of those interactions.Plate Tectonics: Consequences of Plate Interactions? Explain why volcanoes and earthquakes occur along plate boundaries. ? Explain how new sea floor is created and destroyed.? Describe features that may be seen on the surface as a result of plate interactions.Plate Tectonics: Lines of Evidence? Use plate tectonics to explain changes in continents and their positions over geologic time.? Provide evidence for the idea of plates, including the location of earthquakes and volcanoes, continental drift, magnetic orientation of rocks in the ocean floor, etc.

National Science Teachers Association (NSTA)

2007-03-21

202

49 CFR 236.745 - Face, locking.  

Code of Federal Regulations, 2012 CFR

...Transportation 4 2012-10-01 2012-10-01 false Face, locking. 236.745 Section 236.745 Transportation...SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.745 Face, locking. The locking surface of a locking dog, tappet...

2012-10-01

203

49 CFR 236.745 - Face, locking.  

Code of Federal Regulations, 2013 CFR

...Transportation 4 2013-10-01 2013-10-01 false Face, locking. 236.745 Section 236.745 Transportation...SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.745 Face, locking. The locking surface of a locking dog, tappet...

2013-10-01

204

49 CFR 236.745 - Face, locking.  

Code of Federal Regulations, 2014 CFR

...Transportation 4 2014-10-01 2014-10-01 false Face, locking. 236.745 Section 236.745 Transportation...SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.745 Face, locking. The locking surface of a locking dog, tappet...

2014-10-01

205

49 CFR 236.745 - Face, locking.  

Code of Federal Regulations, 2010 CFR

...Transportation 4 2010-10-01 2010-10-01 false Face, locking. 236.745 Section 236.745 Transportation...SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.745 Face, locking. The locking surface of a locking dog, tappet...

2010-10-01

206

49 CFR 236.745 - Face, locking.  

Code of Federal Regulations, 2011 CFR

...Transportation 4 2011-10-01 2011-10-01 false Face, locking. 236.745 Section 236.745 Transportation...SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.745 Face, locking. The locking surface of a locking dog, tappet...

2011-10-01

207

FPGA Based Autonomous Vehicle Locking System A Smart Door Lock  

Microsoft Academic Search

Our paper is termed the Autonomous Vehicle Locking System - A Smart Door Lock. The two main objectives are to unlock a set of vehicle doors when the owner approaches his or her vehicle and to lock the vehicle after the owner leaves. In order to design this system, the establishment of wireless communication between the vehicle owner and their

S. N. Singh; Jayendra Kumar; Ravi Pratap Singh; Sanjay Kumar

2009-01-01

208

Eighth international congress on nitrogen fixation  

SciTech Connect

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.

Not Available

1990-01-01

209

DINITROGEN FIXATION IN ILLINOIS BUNDLEFLOWER  

Technology Transfer Automated Retrieval System (TEKTRAN)

Illinois bundleflower [Desmanthus illinoensis (Michx.) MacMillan] is a warm-season perennial forage legume that may serve as a pulse crop. Its productivity is influenced by its N2 fixation capability. Our objective was to estimate symbiotic N2 fixation of three Illinois bundleflower accessions from ...

210

Plate motion  

SciTech Connect

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.

Gordon, R.G. (USAF, Geophysics Laboratory, Hanscom AFB, MA (United States))

1991-01-01

211

Integrated optical phase locked loop.  

SciTech Connect

A silicon photonics based integrated optical phase locked loop is utilized to synchronize a 10.2 GHz voltage controlled oscillator with a 509 MHz mode locked laser, achieving 32 fs integrated jitter over 300 kHz bandwidth.

Lentine, Anthony L.; Kim, Jungwon (Massachusetts Institute of Technology, Cambridge, MA); Trotter, Douglas Chandler; DeRose, Christopher T.; Kartner, Franz X. (Massachusetts Institute of Technology, Cambridge, MA); Byun, Hyunil (Massachusetts Institute of Technology, Cambridge, MA); Nejadmalayeri, Amir H. (Massachusetts Institute of Technology, Cambridge, MA); Watts, Michael R.; Zortman, William A.

2010-12-01

212

Integrated optical phase locked loop  

Microsoft Academic Search

A silicon photonics based integrated optical phase locked loop is utilized to synchronize a 10.2 GHz voltage controlled oscillator with a 509 MHz mode locked laser, achieving 32 fs integrated jitter over 300 kHz bandwidth.

Anthony L. Lentine; Jungwon Kim; Douglas Chandler Trotter; Christopher T. DeRose; Franz X. Kartner; Hyunil Byun; Amir H. Nejadmalayeri; Michael R. Watts; William A. Zortman

2010-01-01

213

Locking of the Chile subduction zone controlled by fluid pressure before the 2010 earthquake  

NASA Astrophysics Data System (ADS)

Constraints on the potential size and recurrence time of strong subduction-zone earthquakes come from the degree of locking between the down-going and overriding plates, in the period between large earthquakes. In many cases, this interseismic locking degree correlates with slip during large earthquakes or is attributed to variations in fluid content at the plate interface. Here we use geodetic and seismological data to explore the links between pore-fluid pressure and locking patterns at the subduction interface ruptured during the magnitude 8.8 Chile earthquake in 2010. High-resolution three-dimensional seismic tomography reveals variations in the ratio of seismic P- to S-wave velocities (Vp/Vs) along the length of the subduction-zone interface. High Vp/Vs domains, interpreted as zones of elevated pore-fluid pressure, correlate spatially with parts of the plate interface that are poorly locked and slip aseismically. In contrast, low Vp/Vs domains, interpreted as zones of lower pore-fluid pressure, correlate with locked parts of the plate interface, where unstable slip and earthquakes occur. Variations in pore-fluid pressure are caused by the subduction and dehydration of a hydrothermally altered oceanic fracture zone. We conclude that variations in pore-fluid pressure at the plate interface control the degree of interseismic locking and therefore the slip distribution of large earthquake ruptures.

Moreno, Marcos; Haberland, Christian; Oncken, Onno; Rietbrock, Andreas; Angiboust, Samuel; Heidbach, Oliver

2014-04-01

214

Surgical rib fixation - Technical aspects.  

PubMed

Surgical rib fixation (SRF) for severe rib fracture injuries is increasingly becoming an accepted treatment modality. There is now adequate evidence in randomised controlled trials that rib fixation in flail chest patients reduces ventilator times, intensive care stay and costs of treatment in ventilator dependent patients [1-3]. Despite this, rib fixation has not become standard of care for these patients and remains a treatment modality practised by few centres, usually those with large trauma loads who see high volumes of severe rib fracture injury patients. The purpose of this article is to outline the available prostheses, indications, operative planning and techniques of rib fixation. Surgical approaches to rib fractures in anterior, lateral and posterior positions are described as are the use of currently available cortical and medullary fixation prostheses. PMID:25624272

Marasco, Silvana; Saxena, Pankaj

2015-05-01

215

Plate Tectonics  

NSDL National Science Digital Library

Students will go over the main points of plate tectonics, including the theory of continental drift, different types of plate boundaries, seafloor spreading, and convection currents. We have been spending time learning about plate tectonics. We have discussed the theory of continental drift, we have talked about the different types of plate boundaries, we have also learned about seafloor spreading and convection currents. Plate Boundary Diagram Now is your chance ...

Mrs. Rohlfing

2011-02-03

216

The sustentaculum tali screw fixation for the treatment of Sanders type II calcaneal fracture: A finite element analysis  

PubMed Central

Objective: In the surgery of calcaneal fracture, whether the sustentaculum tali screw should always be placed is widely controversial. The aim of this study was to explore the necessity and function of the sustentaculum tali screw placement for the treatment of Sanders type II calcaneal fracture. Methods: The finite element analysis was used in this study. After the establishment of the finite element model of Sanders type II calcaneal fracture, the two internal fixation simulations were designed. In one model, the AO calcaneal plate was simulated on the lateral side of the calcanues with 7 screws being fixated at different position of the plate. In the other model, the calcaneus was fixated with the same AO calcaneal plate together with an additional screw being infiltrated into the sustentaculum tali. The two models were simulated under the same loading and the displacement of the fracture line and the stress distribution in the two models were calculated respectively. Results: The maximum principal stress focused on the cortical bone of sustentaculum tali in both the models under the same loading. The displacement of the fracture line, the maximum principal stress of calcaneus and internal fixation system in the model with sustentaculum screw fixation were smaller than that in the model without sustentaculum screw fixation. The stress in the model with sustentaculum screw fixation was more dispersed. Conclusions: The placement of sustentaculum tali screw is essential for fixation of type II calcaneal fracture to achieve the biomechanical stability. PMID:25225534

Pang, Qing-Jiang; Yu, Xiao; Guo, Zong-Hui

2014-01-01

217

Cement-Lock for Decontaminating  

E-print Network

Cement-Lock® Technology for Decontaminating Dredged Estuarine Sediments Topical Report N O L O G Y I N S T I T U T E Cement-Lock Demo Plant Prepared by: Michael C. Mensinger GAS conducted as part of the overall program "Cement-Lock®1 Technology for Decontaminating Dredged Estuarine

Brookhaven National Laboratory

218

Locke y la filosofía política  

Microsoft Academic Search

This article analyzes the status that Locke grants to normative language and the importance of the argument of the Second Tratise on Civil Government. The author suggests that Locke -as is usual in his time-period- mathematizes normative language, thus favoring the subjectivization of politics. He proposes, as well, that the importance of Locke's argument lies in the performative effect that

Carlos Peña González

2004-01-01

219

Positioning and locking apparatus  

DOEpatents

A positioning and locking apparatus are disclosed including a fixture having a rotatable torque ring provided with a plurality of cam segments for automatically guiding a container into a desired location within the fixture. Rotation of the ring turns the container into a final position in pressure sealing relation against a hatch member. 6 figs.

Hayward, M.L.; Harper, W.H.

1987-06-30

220

Positioning and locking apparatus  

DOEpatents

A positioning and locking apparatus including a fixture having a rotatable torque ring provided with a plurality of cam segments for automatically guiding a container into a desired location within the fixture. Rotation of the ring turns the container into a final position in pressure sealing relation against a hatch member.

Hayward, M.L.; Harper, W.H.

1985-06-19

221

Positioning and locking apparatus  

DOEpatents

A positioning and locking apparatus including a fixture having a rotatable torque ring provided with a plurality of cam segments for automatically guiding a container into a desired location within the fixture. Rotation of the ring turns the container into a final position in pressure sealing relation against a hatch member.

Hayward, Milton L. (2305 Greenbrook Blvd., Richland, WA 99352); Harper, William H. (1454 Amon Dr., Richland, WA 99352)

1987-01-01

222

Roller Locking Brake  

NASA Technical Reports Server (NTRS)

Roller locking brake is normally braking rotary mechanism allowing free rotation when electromagnet in mechanism energized. Well suited to robots and other machinery which automatic braking upon removal of electrical power required. More compact and reliable. Requires little electrical power to maintain free rotation and exhibits minimal buildup of heat.

Vranish, John M.

1993-01-01

223

Atrial fixation leads--a visual aid confirming actual fixation.  

PubMed

Various active fixation mechanisms are available for atrial lead implantation. Confirmation of actual fixation of the lead tip in the myocardium is sometimes difficult with standard techniques such as fluoroscopy. Our observation of organized clockwise/counterclockwise motions of the fixation stylet in synchrony with atrial systole confirms adequate positioning of the Accufix model #330-801 atrial lead in the right atrial appendage, which is helpful when the screw is difficult to visualize under fluoroscopy. This observation was confirmed in nine patients. PMID:1372408

Conti, J B; Curtis, A B

1992-02-01

224

Plate Tectonics  

NSDL National Science Digital Library

This interactive Flash explores plate tectonics and provides an interactive map where users can identify plate boundaries with name and velocities as well as locations of earthquakes, volcanoes, and hotspots. The site also provides animations and supplementary information about plate movement and subduction. This resource is a helpful overview or review for introductory level high school or undergraduate physical geology or Earth science students.

Smoothstone

225

Plate Tectonics  

NSDL National Science Digital Library

Create a poster all about Plate Tectonics! Directions: Make a poster about Plate Tectonics. (20 points) Include at least (1) large picture (15 points) on your poster complete with labels of every part (10 points). (15 points) Include at least three (3) facts about Plate Tectonics. (5 points ...

Mrs. Walls

2011-01-30

226

Molecular Biology of Nitrogen Fixation  

ERIC Educational Resources Information Center

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)

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

1975-01-01

227

Evaluation of Bone Fixation Implants  

E-print Network

This research investigates the effects of the human body on the mechanical, chemical, and morphological properties of the surface of internal fixation devices. Stainless steel and titanium devices that had failed were provided from the Shandong...

Perkins, Luke 1990-

2012-12-10

228

Releasable locking mechanisms  

NASA Technical Reports Server (NTRS)

In the aerospace field spacecraft components are held together by separation systems until a specific time when they must be separated or deployed. Customarily a threaded joining bolt engages one of the components to be joined, and a threaded nut is placed on that bolt against the other component so they can be drawn together by a releasable locking assembly. The releasable locking assembly herein includes a plunger having one end coupled to one end of a plunger bolt. The other end is flanged to abut and compress a coil spring when the plunger is advanced toward the interface plane between the two components. When the plunger is so advanced toward the interface plane, the end of the plunger bolt can be connected to the joining bolt. Thus during retraction the joining bolt is drawn to one side of the interface plane by the force of the expanding spring.

Ahmed, Rafiq (Inventor); Wingate, Robert J. (Inventor)

2005-01-01

229

Releasable Locking Mechanisms  

NASA Technical Reports Server (NTRS)

In the aerospace field spacecraft components are held together by separation systems until a specific time when they must be separated or deployed. Customarily a threaded joining bolt engages one of the components to be joined, and a threaded nut is placed on that bolt against the other component so they can be drawn together by a releasable locking assembly. The releasable locking assembly herein includes a plunger having one end coupled to one end of a plunger bolt. The other end is flanged to abut and compress a coil spring when the plunger is advanced toward the interface plane between the two components. When the plunger is so advanced toward the interface plane, the end of the plunger bolt can be connected to the joining bolt. Thus during retraction the joining bolt is drawn to one side of the interface plane by the force of the expanding spring.

Ahmed, Rafiq (Inventor); Wingate, Robert J. (Inventor)

2005-01-01

230

Data port security lock  

DOEpatents

In a security apparatus for securing an electrical connector, a plug may be fitted for insertion into a connector receptacle compliant with a connector standard. The plug has at least one aperture adapted to engage at least one latch in the connector receptacle. An engagement member is adapted to partially extend through at least one aperture and lock to at least one structure within the connector receptacle.

Quinby, Joseph D. (Albuquerque, NM); Hall, Clarence S. (Albuquerque, NM)

2008-06-24

231

Tectonic Plates and Plate Boundaries  

NSDL National Science Digital Library

This interactive activity adapted from NASA features world maps that identify different sections of the Earth's crust called tectonic plates. The locations of different types of plate boundaries are also identified, including convergent, divergent, and transform boundaries.

2005-12-17

232

[The biological plate osteosynthesis].  

PubMed

The continually evolving understanding of bone biology and the analysis of clinical complications have led to a modified approach in internal fixation using plates. Anatomical reduction of the fragments in comminuted diaphyseal and metaphyseal fractures itself is no longer a goal. Important reduction aims are the correct length of the bone, and axial and torsional alignment. The preservation of the viability of the bone fragments is the key to unimpaired fracture healing. The primary stability of an osteosynthesis seems to be of minor importance for bone healing. More important is the rapid integration of unreduced but vital fragments into the fracture callus which buttresses the fracture area opposite the plate reducing the risk for overload and fatigue failure of the implant. Additional primary bone grafting leeds to local vascular disturbance of the bone and is rarely indicated. Indirect reduction technique with the aid of the fracture table or the distractor and a minimal but optimal use of implant material is the new concept to achieve undisturbed fracture repair in metaphyseal and diaphyseal fractures. In articular fractures the anatomic restoration of the articular surface can be obtained by the combination of indirect reduction technique (ligamentotaxis, soft tissue taxis) and accurate direct reduction of certain strategic fragments. Modifications of the plate design (limited contact, point contact) which minimize additional vascular damage to the bone help to accomplish this new concept. PMID:7975946

Gautier, E; Ganz, R

1994-01-01

233

Assumed strain distributions for a finite strip plate bending element using Mindlin-Reissner plate theory  

NASA Technical Reports Server (NTRS)

A linear finite strip plate element based on Mindlin-Reissner plate theory is developed. The analysis is suitable for both thin and thick plates. In the formulation, new transverse shear strains are introduced and assumed constant in each two-node linear strip. The element stiffness matrix is explicitly formulated for efficient computation and computer implementation. Numerical results showing the efficiency and predictive capability of the element for the analysis of plates are presented for different support and loading conditions and a wide range of thicknesses. No sign of shear locking is observed with the newly developed element.

Chulya, Abhisak; Mullen, Robert L.

1989-01-01

234

4. LOOKING NORTHEAST TOWARDS LOCKS. 19TH CENTURY GRAVITY LOCKS ON ...  

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

4. LOOKING NORTHEAST TOWARDS LOCKS. 19TH CENTURY GRAVITY LOCKS ON RIGHT. 20TH CENTURY ELECTRIC LIFT LOCKS ON LEFT. - New York State Barge Canal, Lockport Locks, Richmond Avenue, Lockport, Niagara County, NY

235

49 CFR 236.338 - Mechanical locking required in accordance with locking sheet and dog chart.  

Code of Federal Regulations, 2014 CFR

...required in accordance with locking sheet and dog chart. 236.338 Section 236.338...required in accordance with locking sheet and dog chart. Mechanical locking shall be in accordance with locking sheet and dog chart currently in...

2014-10-01

236

49 CFR 236.338 - Mechanical locking required in accordance with locking sheet and dog chart.  

Code of Federal Regulations, 2010 CFR

...required in accordance with locking sheet and dog chart. 236.338 Section 236.338...required in accordance with locking sheet and dog chart. Mechanical locking shall be in accordance with locking sheet and dog chart currently in...

2010-10-01

237

49 CFR 236.338 - Mechanical locking required in accordance with locking sheet and dog chart.  

Code of Federal Regulations, 2012 CFR

...required in accordance with locking sheet and dog chart. 236.338 Section 236.338...required in accordance with locking sheet and dog chart. Mechanical locking shall be in accordance with locking sheet and dog chart currently in...

2012-10-01

238

49 CFR 236.338 - Mechanical locking required in accordance with locking sheet and dog chart.  

Code of Federal Regulations, 2013 CFR

...required in accordance with locking sheet and dog chart. 236.338 Section 236.338...required in accordance with locking sheet and dog chart. Mechanical locking shall be in accordance with locking sheet and dog chart currently in...

2013-10-01

239

49 CFR 236.338 - Mechanical locking required in accordance with locking sheet and dog chart.  

Code of Federal Regulations, 2011 CFR

...required in accordance with locking sheet and dog chart. 236.338 Section 236.338...required in accordance with locking sheet and dog chart. Mechanical locking shall be in accordance with locking sheet and dog chart currently in...

2011-10-01

240

Indirect reduction and composite fixation of extraarticular proximal tibial fractures.  

PubMed

Forty-one extraarticular comminuted proximal tibial fractures were treated during a 7-year period. The fractures were proximal tibial metaphyseal injuries or metaphyseal-diaphyseal junction injuries with extension proximally and distally but not involving the knee joint. All fractures were treated surgically with open reduction and internal fixation using an indirect reduction technique with a lateral plate, and a medial substitution external fixator concomitantly. All fractures were seen for followup until they healed (average healing time, 12.1 weeks). The timing of internal fixation was based on the status of the soft tissue (average time to surgery, 8.5 days after injury). A temporary spanning external fixator was used in 17 (41.5%) fractures to allow for further assessment, demarcation, and improvement of the anterior soft tissues. There were 3 (7%) delayed unions, 1 (2%) malunion, and no nonunions. There were 2 (5%) wound infections and 5 (12%) pin track problems. One postsurgical soft tissue problem was encountered. Through this technique, reliable healing and alignment were achieved in this often difficult fracture pattern, particularly for fractures that were difficult or impossible to treat with an intermedullary nail. PMID:7634689

Bolhofner, B R

1995-06-01

241

Safe-haven locking device  

DOEpatents

Disclosed is a locking device for eliminating external control of a secured space formed by fixed and movable barriers. The locking device uses externally and internally controlled locksets and a movable strike, operable from the secured side of the movable barrier, to selectively engage either lockset. A disengagement device, for preventing forces from being applied to the lock bolts is also disclosed. In this manner, a secured space can be controlled from the secured side as a safe-haven. 4 figures.

Williams, J.V.

1984-04-26

242

Backlash-Free Locking Hinge  

NASA Technical Reports Server (NTRS)

Tight joints achieved without precisely machined parts. Hinge for foldable structures locked with minimum force by human operator. Once locked, hinge makes strong, tight joint. Loose fit, or joint slop, common to commercial locking hinges eliminated. Despite tight fit, new hinge concept does not impose close tolerances on manufacture of its parts. Developed for erecting unfoldable structures in space, hinge used on collapsible scaffolds and similar terrestrial structures.

Wessekski, Clarence J.

1987-01-01

243

49 CFR 236.330 - Locking dog of switch-and-lock movement.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Locking dog of switch-and-lock movement. 236.330...Rules and Instructions § 236.330 Locking dog of switch-and-lock movement. Locking dog of switch-and-lock movement shall extend...

2011-10-01

244

49 CFR 236.330 - Locking dog of switch-and-lock movement.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Locking dog of switch-and-lock movement. 236.330...Rules and Instructions § 236.330 Locking dog of switch-and-lock movement. Locking dog of switch-and-lock movement shall extend...

2013-10-01

245

49 CFR 236.330 - Locking dog of switch-and-lock movement.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Locking dog of switch-and-lock movement. 236.330...Rules and Instructions § 236.330 Locking dog of switch-and-lock movement. Locking dog of switch-and-lock movement shall extend...

2010-10-01

246

49 CFR 236.330 - Locking dog of switch-and-lock movement.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Locking dog of switch-and-lock movement. 236.330...Rules and Instructions § 236.330 Locking dog of switch-and-lock movement. Locking dog of switch-and-lock movement shall extend...

2012-10-01

247

49 CFR 236.330 - Locking dog of switch-and-lock movement.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 2014-10-01 false Locking dog of switch-and-lock movement. 236.330...Rules and Instructions § 236.330 Locking dog of switch-and-lock movement. Locking dog of switch-and-lock movement shall extend...

2014-10-01

248

Cervical anterior transpedicular screw fixation. Part I: Study on morphological feasibility, indications, and technical prerequisites  

Microsoft Academic Search

Multilevel cervical spine procedures can challenge the stability of current anterior cervical screw-and-plate systems, particularly\\u000a in cases of severe three-column subaxial cervical spine injuries and multilevel plated reconstructions in osteoporotic bone.\\u000a Supplemental posterior instrumentation is therefore recommended to increase primary construct rigidity and diminish early\\u000a failure rates. The increasing number of successfully performed posterior cervical pedicle screw fixations have enabled

Heiko Koller; Axel Hempfing; Frank Acosta; Michael Fox; Armin Scheiter; Mark Tauber; Ulrich Holz; Herbert Resch; Wolfgang Hitzl

2008-01-01

249

Femoral Reconstruction Using External Fixation  

PubMed Central

Background. The use of an external fixator for the purpose of distraction osteogenesis has been applied to a wide range of orthopedic problems caused by such diverse etiologies as congenital disease, metabolic conditions, infections, traumatic injuries, and congenital short stature. The purpose of this study was to analyze our experience of utilizing this method in patients undergoing a variety of orthopedic procedures of the femur. Methods. We retrospectively reviewed our experience of using external fixation for femoral reconstruction. Three subgroups were defined based on the primary reconstruction goal lengthening, deformity correction, and repair of nonunion/bone defect. Factors such as leg length discrepancy (LLD), limb alignment, and external fixation time and complications were evaluated for the entire group and the 3 subgroups. Results. There was substantial improvement in the overall LLD, femoral length discrepancy, and limb alignment as measured by mechanical axis deviation (MAD) and lateral distal femoral angle (LDFA) for the entire group as well as the subgroups. Conclusions. The Ilizarov external fixator allows for decreased surgical exposure and preservation of blood supply to bone, avoidance of bone grafting and internal fixation, and simultaneous lengthening and deformity correction, making it a very useful technique for femoral reconstruction. PMID:21991425

Palatnik, Yevgeniy; Rozbruch, S. Robert

2011-01-01

250

49 CFR 236.800 - Sheet, locking.  

Code of Federal Regulations, 2011 CFR

...Transportation 4 2011-10-01 2011-10-01 false Sheet, locking. 236.800 Section 236.800 Transportation...SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.800 Sheet, locking. A description in tabular form of the locking...

2011-10-01

251

49 CFR 236.800 - Sheet, locking.  

Code of Federal Regulations, 2014 CFR

...Transportation 4 2014-10-01 2014-10-01 false Sheet, locking. 236.800 Section 236.800 Transportation...SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.800 Sheet, locking. A description in tabular form of the locking...

2014-10-01

252

49 CFR 236.800 - Sheet, locking.  

Code of Federal Regulations, 2013 CFR

...Transportation 4 2013-10-01 2013-10-01 false Sheet, locking. 236.800 Section 236.800 Transportation...SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.800 Sheet, locking. A description in tabular form of the locking...

2013-10-01

253

49 CFR 236.800 - Sheet, locking.  

Code of Federal Regulations, 2012 CFR

...Transportation 4 2012-10-01 2012-10-01 false Sheet, locking. 236.800 Section 236.800 Transportation...SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.800 Sheet, locking. A description in tabular form of the locking...

2012-10-01

254

49 CFR 236.105 - Electric lock.  

Code of Federal Regulations, 2011 CFR

... 4 2011-10-01 2011-10-01 false Electric lock. 236.105 Section 236.105 Transportation...Inspections and Tests; All Systems § 236.105 Electric lock. Electric lock, except forced-drop type, shall be...

2011-10-01

255

49 CFR 236.379 - Route locking.  

Code of Federal Regulations, 2014 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.379 Route locking. Route locking or other type of switch locking shall be...

2014-10-01

256

49 CFR 236.376 - Mechanical locking.  

Code of Federal Regulations, 2011 CFR

...REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.376 Mechanical locking. Mechanical locking in interlocking machine shall be tested when new locking is installed; and...

2011-10-01

257

49 CFR 236.376 - Mechanical locking.  

Code of Federal Regulations, 2014 CFR

...REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.376 Mechanical locking. Mechanical locking in interlocking machine shall be tested when new locking is installed; and...

2014-10-01

258

49 CFR 236.379 - Route locking.  

Code of Federal Regulations, 2011 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.379 Route locking. Route locking or other type of switch locking shall be...

2011-10-01

259

49 CFR 236.336 - Locking bed.  

Code of Federal Regulations, 2013 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Rules and Instructions § 236.336 Locking bed. The various parts of the locking bed, locking bed supports,...

2013-10-01

260

49 CFR 236.336 - Locking bed.  

Code of Federal Regulations, 2012 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Rules and Instructions § 236.336 Locking bed. The various parts of the locking bed, locking bed supports,...

2012-10-01

261

49 CFR 236.379 - Route locking.  

Code of Federal Regulations, 2012 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.379 Route locking. Route locking or other type of switch locking shall be...

2012-10-01

262

49 CFR 236.379 - Route locking.  

Code of Federal Regulations, 2013 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.379 Route locking. Route locking or other type of switch locking shall be...

2013-10-01

263

49 CFR 236.376 - Mechanical locking.  

Code of Federal Regulations, 2013 CFR

...REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.376 Mechanical locking. Mechanical locking in interlocking machine shall be tested when new locking is installed; and...

2013-10-01

264

49 CFR 236.336 - Locking bed.  

Code of Federal Regulations, 2011 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Rules and Instructions § 236.336 Locking bed. The various parts of the locking bed, locking bed supports,...

2011-10-01

265

49 CFR 236.336 - Locking bed.  

Code of Federal Regulations, 2014 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Rules and Instructions § 236.336 Locking bed. The various parts of the locking bed, locking bed supports,...

2014-10-01

266

49 CFR 236.379 - Route locking.  

Code of Federal Regulations, 2010 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.379 Route locking. Route locking or other type of switch locking shall be...

2010-10-01

267

49 CFR 236.336 - Locking bed.  

Code of Federal Regulations, 2010 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Rules and Instructions § 236.336 Locking bed. The various parts of the locking bed, locking bed supports,...

2010-10-01

268

49 CFR 236.376 - Mechanical locking.  

Code of Federal Regulations, 2012 CFR

...REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.376 Mechanical locking. Mechanical locking in interlocking machine shall be tested when new locking is installed; and...

2012-10-01

269

Progressive slip after removal of screw fixation in slipped capital femoral epiphysis: two case reports  

PubMed Central

Introduction In slipped capital femoral epiphysis the femoral neck displaces relative to the head due to weakening of the epiphysis. Early recognition and adequate surgical fixation is essential for a good functional outcome. The fixation should be secured until the closure of the epiphysis to prevent further slippage. A slipped capital femoral epiphysis should not be confused with a femoral neck fracture. Case presentation Case 1 concerns a 15-year-old boy with an adequate initial screw fixation of his slipped capital femoral epiphysis. Unfortunately, it was thought that the epiphysis had healed and the screw was removed after 11 weeks. This caused new instability with a progressive slip of the femoral epiphysis and subsequently re-fixation and a subtrochanteric correction osteotomy was obligatory. Case 2 concerns a 13-year-old girl with persistent hip pain after screw fixation for slipped capital femoral epiphysis. The screw was removed as lysis was seen around the screw on the hip X-ray. This operation created a new unstable situation and the slip progressed resulting in poor hip function. A correction osteotomy with re-screw fixation was performed with a good functional result. Conclusion A slipped epiphysis of the hip is not considered ‘healed’ after a few months. Given the risk of progression of the slip the fixation material cannot be removed before closure of the growth plate. PMID:23181447

2012-01-01

270

Translaminar screw fixation in the subaxial pediatric cervical spine.  

PubMed

The use of spinal instrumentation to stabilize the occipitocervical junction in pediatric patients has increased and evolved in recent years. Wiring techniques have now given way to screw-rod or screw-plate techniques with or without postoperative external immobilization. Although C-2 translaminar screws have been used in these constructs, subaxial translaminar screws have not, to date, been described in either the pediatric or adult patient populations. The authors describe the feasibility of translaminar screw placement in the C-3 lamina. Rigid fixation with translaminar screws offers an alternative to subaxial fixation with lateral mass screws, allowing for formation of biomechanically sound spinal constructs and minimizing potential neurovascular morbidity. Their use requires careful analysis of preoperative imaging studies, intact posterior elements, and avoidance of violation of the inner laminar wall. PMID:19035682

Jea, Andrew; Johnson, Keyne K; Whitehead, William E; Luerssen, Thomas G

2008-12-01

271

A new adhesive technique for internal fixation in midfacial surgery  

PubMed Central

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 the detected adhesion forces of ca. 6 to 8 MPa, it is assumed that the adhesive fixation system is able to secure bone fragments from the non-load bearing midfacial regions in their orthotopic positions until fracture consolidation is complete. PMID:18489785

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

2008-01-01

272

Antifungal Lock Therapy  

PubMed Central

The widespread use of intravascular devices, such as central venous and hemodialysis catheters, in the past 2 decades has paralleled the increasing incidence of catheter-related bloodstream infections (CR-BSIs). Candida albicans is the fourth leading cause of hospital-associated BSIs. The propensity of C. albicans to form biofilms on these catheters has made these infections difficult to treat due to multiple factors, including increased resistance to antifungal agents. Thus, curing CR-BSIs caused by Candida species usually requires catheter removal in addition to systemic antifungal therapy. Alternatively, antimicrobial lock therapy has received significant interest and shown promise as a strategy to treat CR-BSIs due to Candida species. The existing in vitro, animal, and patient data for treatment of Candida-related CR-BSIs are reviewed. The most promising antifungal lock therapy (AfLT) strategies include use of amphotericin, ethanol, or echinocandins. Clinical trials are needed to further define the safety and efficacy of AfLT. PMID:23070153

Walraven, Carla J.

2013-01-01

273

Evaluation of Bite Force After Open Reduction and Internal Fixation Using Microplates  

PubMed Central

The primary aim of this study is to determine maximum bite force in molar and incisor regions of healthy individuals, to evaluate the bite force after open reduction and internal fixation of mandibular fractures using micro plates, for a period of up to 6 weeks and to determine the rate of recovery of maximum bite force in an Indian population. PMID:24910656

Kumar, S Tharani; Saraf, Saurabh; Devi, S Prasanna

2013-01-01

274

Clinical and radiographic evaluation of biodegradable bone plates in the treatment of mandibular body fractures  

PubMed Central

Background: Many different systems are available for the treatment of fractures ranging from the heavy compression plates for mandibular reconstruction to low profile plates for mid-facial fixation, and are made either from stainless steel, titanium or vitallium. Recently, biodegradable, self-reinforced polylactide plates and screws have been used for the internal fixation of fractures of the mandible with good results. Aim of this study: This study evaluated clinically the biodegradable bone plates for treatment of mandibular body fracture and to evaluate bone healing during the follow-up period using digital radiography. Materials and Methods: Eight patients had been suffered from mandibular body fractures were treated using Inion CPSTM bioresorbable fixation system and the healing process were followed up using digitised panoramic radiography at first week and after 1, 3 and 6 months. Results: Clinical examination of fractured segments revealed stable fixation across the fracture sites while visual and quantitative assessment of radiograph showed healing process was comparable with results previously reported by titanium bone plates. Conclusion: Open reduction and internal fixation of mandibular fractures using bioresorbable fixation system with a brief period of inter-maxillary fixation have evolved to the point where the physical properties are sufficient to withstand the post-operative loads required for fracture repair of mandibular body fractures. The foreign body reaction is a major material-related problem which requires further studies. PMID:25657494

Elhalawany, Sherin Kamal; Tarakji, Bassel; Azzeghaiby, SN; Alzoghaibi, Ibrahim; Baroudi, Kusai; Nassani, Mohammad Zakaria

2015-01-01

275

Globalizing carbon lock-in  

Microsoft Academic Search

This paper extends the arguments surrounding carbon lock-in elaborated in Unruh (Energy Policy 28 (2000) 817; 30 (2002) 317) to countries currently undergoing industrialization. It argues that, for numerous reasons, industrializing countries are unlikely to leapfrog carbon intensive energy development. On the contrary, carbon lock-in may be globalizing and could further constrain climate change mitigation options. It is then argued

Gregory C. Unruh; Javier Carrillo-Hermosilla

2006-01-01

276

Molybdenum Trafficking for Nitrogen Fixation  

PubMed Central

The molybdenum nitrogenase is responsible for most biological nitrogen fixation, a prokaryotic metabolic process that determines the global biogeochemical cycles of nitrogen and carbon. Here we describe the trafficking of molybdenum for nitrogen fixation in the model diazotrophic bacterium Azotobacter vinelandii. The genes and proteins involved in molybdenum uptake, homeostasis, storage, regulation, and nitrogenase cofactor biosynthesis are reviewed. Molybdenum biochemistry in A. vinelandii reveals unexpected mechanisms and a new role for iron-sulfur clusters in the sequestration and delivery of molybdenum. PMID:19772354

Hernandez, Jose A.; George, Simon J.; Rubio, Luis M.

2009-01-01

277

Broken nylon iris fixation sutures.  

PubMed

Broken nylon iris sutures, used to fixate the Worst suture lens, occurred in 41 of a series of 215 eyes, a remarkably high frequency. The estimated average time to break was 27.8 months. Over three fourths of the borken sutures were discovered incidentally on a return visit. Complications related to the broken suture occurred in 21 eyes. The characteristic complication was corneal epithelial edema caused by intermittent touch of the endothelium by the broken suture; spontaneous lens dislocation was infrequent. Light and scanning electron microscopy revealed that biodegradation caused the suture break. Broken iris sutures can be avoided by fixation of the lens with a nonbiodegradable suture. PMID:517621

Cohan, B E; Pearch, A C; Schwartz, S

1979-12-01

278

Plate Tectonics  

NSDL National Science Digital Library

In this lesson, students are introduced to the theory of plate tectonics and explore how the theory was developed and supported by evidence. Through class discussion, videos, and activities, students seek connections between tectonic activity and geologic features and investigate how the theory of plate tectonics evolved.

2006-01-01

279

Plate Tectonics  

NSDL National Science Digital Library

This site contains 25 questions on the topic of plate tectonics, which covers the development of the theory, crustal movements, geologic features associated with tectonics, and plate boundaries (convergent, divergent, transform). This is part of the Principles of Earth Science course at the University of South Dakota. Users submit their answers and are provided immediate verification.

Timothy Heaton

280

Double-Acting, Locking Carabiners  

NASA Technical Reports Server (NTRS)

A proposed design for carabiners (tether hooks used in mountaineering, rock climbing, and rescue) is intended to make it possible to operate these devices even while wearing thick gloves. According to the proposal, the gate of a carabiner would be capable of swinging either toward or away from the hook body, relative to the closed position. The gate would be spring-biased to return to the closed position. An external locking collar would be pinned to an internal locking rod that would be springloaded to slide the collar longitudinally over the gate to lock the gate in the closed position. The gate would be unlocked by sliding the collar axially against the spring load. To reduce the probability of inadvertent unlocking, the rod-and-collar mechanism would include two locking buttons. Optionally, the rod-and-collar mechanism could be replaced with an external locking mechanism based on a longer collar.

Chang, Chi-Min; LiDelRosso, Dominic

2004-01-01

281

Proximal tibia medial open-wedge osteotomy using plates with wedges: early results in 58 cases  

Microsoft Academic Search

We evaluated in this study indications, surgical technique, and results of wedge plates for fixation in proximal tibia medial opening wedge osteotomy. Fifty-eight knees in 56 consecutive patients (9 men, 47 women; mean age 52 years; ranging between 36 and 66 years) with medial compartment osteoarthrosis were treated with proximal tibia medial open-wedge osteotomy. For fixation, plates which were designed by the

Irfan Esenkaya; Nurzat Elmali

2006-01-01

282

NCI-Frederick PHL - Fixatives and Solutions  

Cancer.gov

Services Price List Courier Services & Shipment Procedures Scheduling Contact Information Related Links Establishing an Account PHL Forms PHL Portal Fixatives and Solutions Routine fixatives: 10% Neutral Buffered Formalin (NBF) 37 - 40% Formaldehyde………………………………………1000mL distilled

283

Plate motions: fundamentals  

E-print Network

lithospheric plates" · Plate tectonics = a kinematic theory ­ Rigid plates (no intraplate deformation") · Convergent = subductions ("trenches") · Strike-slip = transform faults · Plate tectonics describesPlate motions: fundamentals · Assume a pie-shaped wedge plate B, rotating around E (=rotation pole

Déverchère, Jacques

284

49 CFR 236.766 - Locking, movable bridge.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Locking, movable bridge. 236.766 Section 236.766 Transportation... Definitions § 236.766 Locking, movable bridge. The rail locks, bridge locks, bolt locks, circuit controllers,...

2010-10-01

285

Tissue fixation and the effect of molecular fixatives on downstream staining procedures  

PubMed Central

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. PMID:24561827

Howat, William J.; Wilson, Beverley A.

2014-01-01

286

Is distal locking of long nails for intertrochanteric fractures necessary? A clinical study  

PubMed Central

Background Few clinical studies have examined the utility of distal interlocking nails when fixing intertrochanteric fractures with intramedullary devices. In this study we performed a retrospective analysis comparing fixation method of intertrochanteric fractures with either a long unlocked cephalomedullary nail versus a long locked cephalomedullary nail. Our hypothesis was there would be no difference in device related failures or complications in stable intertrochanteric fractures treated with long locked or long unlocked cephalomedullary nails. Methods A retrospective chart review was performed of all stable intertrochanteric fractures treated with a long cephalomedullary nail between 2006 and 2012 at our institution. Clinical history as well as perioperative radiography was carefully reviewed for all subjects. AO classification, the use of locked or unlocked technique, and failure status was recorded. Results Overall, a device related failure rate of 1.8% (2/107) was observed for stable intertrochanteric fractures treated with long cephalomedullary nails. No statistical difference in failure rate was found between locked and unlocked nails within our studied population (0% long locked (0/56) versus 3.9% long unlocked (2/51), p = 0.224). Conclusion This clinical study supports our hypothesis that long cephalomedullary nails do not need to be locked for stable intertrochanteric fractures. We found no difference in failure rates between the two approaches across 107 patients.

Vopat, Bryan G.; Kane, Patrick M.; Truntzer, Jeremy; McClure, Philip; Paller, David; Abbood, Emily; Born, Christopher

2014-01-01

287

Allograft interference screw fixation in meniscus transplantation  

Microsoft Academic Search

Allograft meniscus transplantation is indicated to restore proper knee biomechanics and prevent subsequent articular degeneration in patients with a meniscus-deficient knee. A variety of techniques for fixation of meniscal transplants exist, with some techniques using soft-tissue fixation of the meniscal horns and others using bony fixation. The authors present a technique of meniscus transplantation using a tibial slot with allograft

Jack Farr; R. Michael Meneghini; Brian J. Cole

2004-01-01

288

Occipital condyle to cervical spine fixation in the pediatric population.  

PubMed

Fixation at the craniovertebral junction (CVJ) is necessary in a variety of pediatric clinical scenarios. Traditionally an occipital bone to cervical fusion is preformed, which requires a large amount of hardware to be placed on the occiput of a child. If a patient has previously undergone a posterior fossa decompression or requires a decompression at the time of the fusion procedure, it can be difficult to anchor a plate to the occipital bone. The authors propose a technique that can be used when faced with this difficult challenge by using the occipital condyle as a point of fixation for the construct. Adult cadaveric and a limited number of case studies have been published using occipital condyle (C-0) fixation. This work was adapted for the pediatric population. Between 2009 and 2012, 4 children underwent occipital condyle to axial or subaxial spine fixation. One patient had previously undergone posterior fossa surgery for tumor resection, and 1 required decompression at the time of operation. Two patients underwent preoperative deformity reduction using traction. One child had a Chiari malformation Type I. Each procedure was performed using polyaxial screw-rod constructs with intraoperative neuronavigation supplemented by a custom navigational drill guide. Smooth-shanked 3.5-mm polyaxial screws, ranging in length from 26 to 32 mm, were placed into the occipital condyles. All patients successfully underwent occipital condyle to cervical spine fixation. In 3 patients the construct extended from C-0 to C-2, and in 1 from C-0 to T-2. Patients with preoperative halo stabilization were placed in a cervical collar postoperatively. There were no new postoperative neurological deficits or vascular injuries. Each patient underwent postoperative CT, demonstrating excellent screw placement and evidence of solid fusion. Occipital condyle fixation is an effective option in pediatric patients requiring occipitocervical fusion for treatment of deformity and/or instability at the CVJ. The use of intraoperative neuronavigation allows for safe placement of screws into C-0, especially when faced with a challenging patient in whom fixation to the occipital bone is not possible or is less than ideal. PMID:24206344

Kosnik-Infinger, Libby; Glazier, Steven S; Frankel, Bruce M

2014-01-01

289

Phase-Locked Loops  

NSDL National Science Digital Library

Phase-locked loops (PLL) are unique feedback control circuits that offer many useful features and benefits in electronic applications. PLLs are available either in integrated circuit (IC) form for general applications or built into larger system IC chips. Today, PLLs are found in virtually all types of electronic equipment from PCs to consumer products like TV sets and cell phones. This module provides an introduction to the PLL and its applications. It begins with an overview of the main components of a PLL and how these components work together. It then describes PLL specifications and a description of the most widely used applications including frequency synthesizers, clock multipliers, clock and data recovery circuits, FM demodulators, and filters.

290

Payload Launch Lock Mechanism  

NASA Technical Reports Server (NTRS)

A payload launch lock mechanism includes a base, a preload clamp, a fastener, and a shape memory alloy (SMA) actuator. The preload clamp is configured to releasibly restrain a payload. The fastener extends, along an axis, through the preload clamp and into the base, and supplies a force to the preload clamp sufficient to restrain the payload. The SMA actuator is disposed between the base and the clamp. The SMA actuator is adapted to receive electrical current and is configured, upon receipt of the electrical current, to supply a force that causes the fastener to elongate without fracturing. The preload clamp, in response to the fastener elongation, either rotates or pivots to thereby release the payload.

Young, Ken (Inventor); Hindle, Timothy (Inventor)

2014-01-01

291

Methacarn (methanol-Carnoy) fixation  

Microsoft Academic Search

According to chemical data, methanol raises the shrinkage temperature of collagen significantly more than ethanol (86° C versus 70° C). Since increase of shrinkage temperature appears desirable in tissues to be embedded in paraffin, methanol was substituted for ethanol in Carnoy's fluid. This methanol-Carnoy mixture is referred to as methacarn solution. The fixation-embedding procedure was similar to that described in

Holde Puchtler; Faye Sweat Waldrop; Susan N. Meloan; Mary S. Terry; H. M. Conner

1970-01-01

292

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

PubMed Central

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?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

2014-01-01

293

Understanding Nitrogen Fixation  

SciTech Connect

The purpose of our program is to explore fundamental chemistry relevant to the discovery of energy efficient methods for the conversion of atmospheric nitrogen (N{sub 2}) into more value-added nitrogen-containing organic molecules. Such transformations are key for domestic energy security and the reduction of fossil fuel dependencies. With DOE support, we have synthesized families of zirconium and hafnium dinitrogen complexes with elongated and activated N-N bonds that exhibit rich N{sub 2} functionalization chemistry. Having elucidated new methods for N-H bond formation from dihydrogen, C-H bonds and Broensted acids, we have since turned our attention to N-C bond construction. These reactions are particularly important for the synthesis of amines, heterocycles and hydrazines with a range of applications in the fine and commodity chemicals industries and as fuels. One recent highlight was the discovery of a new N{sub 2} cleavage reaction upon addition of carbon monoxide which resulted in the synthesis of an important fertilizer, oxamide, from the diatomics with the two strongest bonds in chemistry. Nitrogen-carbon bonds form the backbone of many important organic molecules, especially those used in the fertilizer and pharamaceutical industries. During the past year, we have continued our work in the synthesis of hydrazines of various substitution patterns, many of which are important precursors for heterocycles. In most instances, the direct functionalization of N{sub 2} offers a more efficient synthetic route than traditional organic methods. In addition, we have also discovered a unique CO-induced N{sub 2} bond cleavage reaction that simultaneously cleaves the N-N bond of the metal dinitrogen compound and assembles new C-C bond and two new N-C bonds. Treatment of the CO-functionalized core with weak Broensted acids liberated oxamide, H{sub 2}NC(O)C(O)NH{sub 2}, an important slow release fertilizer that is of interest to replace urea in many applications. The 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 atmospheric nitrogen could, in principle, be more energy-efficient. This is particularly attractive giv

Paul J. Chirik

2012-05-25

294

Plate Motions  

NSDL National Science Digital Library

To prepare for this exercise students read the Chapter on plate tectonics in their text book. In class, they are given a color isochron map of the sea floor. They are given 4 tasks: Answer basic questions about the timing and rate of opening of the N. and S. Atlantic; Determine what has happened to the oceanic crust that is created on the eastern side of the East Pacific Rise; Determine what type of plate boundary existed on the western edge of the N. America plate before the San Andreas Fault and when this transition occurred; and Reconstruct the motion of the plates over the last 40 Ma assuming that the surface area of the Earth has not changed.

Jeffrey Nunn

295

Nonunion after trapeziometacarpal arthrodesis: comparison between K-wire and internal fixation.  

PubMed

We reviewed 63 trapeziometacarpal arthrodeses (57 patients) performed in our unit between April 2007 and May 2013 for osteoarthritis. K-wires, plates, headless compression screws and memory staples were used for fixation. The average age of patients was 50 (range 20-78) years and there were 36 men and 21 women with a mean follow-up of 36 (range 6-62) months. K-wires were used in 31 cases, staples in 12, plates in five, and screws in 15 joints. The overall non-union rate was 11%, however, when using K-wires for fixation, it was 20%. Union was achieved in all cases when staples or screws were used for fixation. Disabilities of the Arm, Shoulder and Hand scores were higher in cases where non-union occurred compared with those that united (66.7 vs. 21.9). Trapeziometacarpal arthrodesis for osteoarthritis gives good clinical outcome with lower (DASH) scores when union occurs. K-wire fixation led to a 20% non-union rate, and as a result, the senior author no longer uses this method of fixation. PMID:24916633

Singh, H P; Hoare, C; Beresford-Cleary, N; Anakwe, R; Hayton, M

2015-05-01

296

Plate Tectonics  

NSDL National Science Digital Library

This data tip from Bridge, the Ocean Sciences Education Teacher Resource Center archive, includes a variety of educational sites to visit on plate tectonic theory. Learners can use underwater earthquake data to identify plate boundaries with links to the National Oceanic and Atmospheric Administration's Acoustic Monitoring Program Ocean Seismicity data. Data from the Northeast Pacific, eastern Equatorial Pacific, and North Atlantic are examined in more detail.

297

Dually-mode-locked ND: YAG laser  

NASA Technical Reports Server (NTRS)

Mode-locking is stabilized effectively by conventional loss-modulator and phase-modulator, mode-locking elements placed in laser cavity in optical series with one another. Resulting dually-mode-locked system provides pulses with constant phase relative to mode-lock drive signal without presence of relaxation oscillation noise.

Osmundson, J.; Rowe, E.; Santarpia, D.

1974-01-01

298

Abortable Reader-Writer Locks are No More Complex Than Abortable Mutex Locks  

E-print Network

Abortable Reader-Writer Locks are No More Complex Than Abortable Mutex Locks Dartmouth Computer on designing abortable mutual exclusion locks, and fairly efficient algorithms of O(log n) RMR complexity have). The abort feature is just as important for a reader-writer lock as it is for a mutual exclusion lock

299

Cavity-locked ring down spectroscopy  

DOEpatents

Distinct locking and sampling light beams are used in a cavity ring-down spectroscopy (CRDS) system to perform multiple ring-down measurements while the laser and ring-down cavity are continuously locked. The sampling and locking light beams have different frequencies, to ensure that the sampling and locking light are decoupled within the cavity. Preferably, the ring-down cavity is ring-shaped, the sampling light is s-polarized, and the locking light is p-polarized. Transmitted sampling light is used for ring-down measurements, while reflected locking light is used for locking in a Pound-Drever scheme.

Zare, Richard N. (Stanford, CA); Paldus, Barbara A. (Stanford, CA); Harb, Charles C. (Palo Alto, CA); Spence, Thomas (Union City, CA)

2000-01-01

300

Finite-element modelling of femoral shaft fracture fixation techniques post total hip arthroplasty.  

PubMed

The presence of a femoral prosthesis superior to a shaft fracture severely complicates fixation and treatment. This study uses two-dimensional, multithickness, plane stress finite-element models of a femur with prosthesis to investigate the stresses developed with the application of three popular fixation techniques: revision to a long stem prosthesis, lateral plating with a cortical bone allograft strut and cerclage wires, and custom plate application with proximal Parham band fixation with distal cortical screws (Ogden plate). The plate and bone contact as well as the fracture site contact were modelled by using orthotropic elements with custom-fit moduli so that only the normal stress to the interface was significant. A thermal analogy was used to model the cerclage and Parham band preloads so that representative preloads in the proximal fixation of the two types of plate treatments could be modelled. A parametric study was performed with the long-prosthesis model to show variations in stem lengths of one, two and three femoral diameters distal to the fracture site. The Ogden plate model showed a transfer of tensile stress near the proximal-most band, with the highest tensile stress being at the fracture site with evidence of stress shielding of the proximal lateral cortex. The cortical bone strut model showed a transfer of tensile stress to the bone strut but showed less shielding of the proximal cortex. The cerclage wires at the base of the bone strut showed the highest changes in load with the distalmost wire increasing to almost four times its original preload.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1592852

Mihalko, W M; Beaudoin, A J; Cardea, J A; Krause, W R

1992-05-01

301

Effect of screw placement on fixation in the humeral head.  

PubMed

The objectives of this study were (1) to determine the most advantageous screw locations within the humeral head when plate and screw fixation is to be used and (2) to determine the effect of positioning the screw tip abutting the subchondral bone. Ten paired humeral heads were harvested with a monoplanar cut through the anatomic neck. Through use of a standardized template, 7 holes were drilled and tapped in each specimen for insertion of 6.5-mm fully threaded cancellous screws perpendicular to the plane of the cut. Paired specimens were randomized into 2 groups, one with the screw purchase in central cancellous bone and the other with the screw purchase up to the subchondral bone. Each screw was pulled out axially at a displacement rate of 10 mm/min through use of a servohydraulic testing machine. The length of thread purchase, position within the head, and screw pullout load to failure were recorded. The normalized pullout force to failure was calculated by dividing absolute pullout force to failure by length of screw purchase. Data were analyzed by means of a 2-way repeated measures analysis of variance and post hoc Student-Newman-Keuls test. The central position had a significantly higher absolute pullout force to failure than all other sites (P < .05). By virtue of the humeral head shape, the central position also had a significantly greater length of screw purchase than all other positions (P < .05). The central position had a significantly higher relative pullout force to failure than all other positions (P < .05). Subchondral bone abutment positioning improved both the absolute and the relative pullout forces to failure (P < .05). When screws and plates are used in open reduction and internal fixation of a proximal humerus fracture, a major mode of failure is loss of fixation within the humeral head. On the basis of this study, optimal screw purchase with respect to bone fixation can be achieved by including screws located in the center of the humeral head in the subchondral abutment position. To minimize screw fixation failure, the anterosuperior position should be avoided. The pattern of distribution of the relative pullout force as measured in this study is consistent with previous observational studies of patterns of trabecular density within the humeral head. PMID:11075327

Liew, A S; Johnson, J A; Patterson, S D; King, G J; Chess, D G

2000-01-01

302

49 CFR 236.337 - Locking faces of mechanical locking; fit.  

Code of Federal Regulations, 2010 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Rules and Instructions § 236.337 Locking faces of mechanical locking; fit. Locking faces shall fit squarely...

2010-10-01

303

49 CFR 236.337 - Locking faces of mechanical locking; fit.  

Code of Federal Regulations, 2012 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Rules and Instructions § 236.337 Locking faces of mechanical locking; fit. Locking faces shall fit squarely...

2012-10-01

304

49 CFR 236.337 - Locking faces of mechanical locking; fit.  

Code of Federal Regulations, 2011 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Rules and Instructions § 236.337 Locking faces of mechanical locking; fit. Locking faces shall fit squarely...

2011-10-01

305

49 CFR 236.306 - Facing point lock or switch-and-lock movement.  

Code of Federal Regulations, 2012 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Standards § 236.306 Facing point lock or switch-and-lock movement. Facing point lock or...

2012-10-01

306

49 CFR 236.306 - Facing point lock or switch-and-lock movement.  

Code of Federal Regulations, 2013 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Standards § 236.306 Facing point lock or switch-and-lock movement. Facing point lock or...

2013-10-01

307

49 CFR 236.306 - Facing point lock or switch-and-lock movement.  

Code of Federal Regulations, 2014 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Standards § 236.306 Facing point lock or switch-and-lock movement. Facing point lock or...

2014-10-01

308

49 CFR 236.337 - Locking faces of mechanical locking; fit.  

Code of Federal Regulations, 2014 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Rules and Instructions § 236.337 Locking faces of mechanical locking; fit. Locking faces shall fit squarely...

2014-10-01

309

49 CFR 236.306 - Facing point lock or switch-and-lock movement.  

Code of Federal Regulations, 2011 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Standards § 236.306 Facing point lock or switch-and-lock movement. Facing point lock or...

2011-10-01

310

49 CFR 236.337 - Locking faces of mechanical locking; fit.  

Code of Federal Regulations, 2013 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Rules and Instructions § 236.337 Locking faces of mechanical locking; fit. Locking faces shall fit squarely...

2013-10-01

311

Musical Plates  

NSDL National Science Digital Library

This on-line project is part of the Center for Improved Engineering and Science Education (CIESE) program. As they complete this series of lessons, students will use real-time data to solve a problem, study the correlation between earthquakes and tectonic plates, and determine whether or not there is a relationship between volcanoes and plate boundaries. Musical Plates has four Core Activities that will teach students how to access and interpret real-time earthquake and volcano data and to how use the information to solve a real-world problem. Each of the core activities is designed to be used in a 45-minute class period. This unit also has three enrichment lessons and a final project lesson that can also be used for assessment.

2007-12-12

312

Fixational eye movements and binocular vision  

PubMed Central

During attempted visual fixation, small involuntary eye movements–called fixational eye movements–continuously change of our gaze’s position. Disagreement between the left and right eye positions during such motions can produce diplopia (double vision). Thus, the ability to properly coordinate the two eyes during gaze fixation is critical for stable perception. For the last 50 years, researchers have studied the binocular characteristics of fixational eye movements. Here we review classical and recent studies on the binocular coordination (i.e., degree of conjugacy) of each fixational eye movement type: microsaccades, drift and tremor, and its perceptual contribution to increasing or reducing binocular disparity. We also discuss how amblyopia and other visual pathologies affect the binocular coordination of fixational eye movements. PMID:25071480

Otero-Millan, Jorge; Macknik, Stephen L.; Martinez-Conde, Susana

2014-01-01

313

Overcoming fixation with repeated memory suppression.  

PubMed

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. PMID:24575886

Angello, Genna; Storm, Benjamin C; Smith, Steven M

2015-04-01

314

Impact response and simulation of damaged ulna with internal fixation.  

PubMed

The objectives of this work were to explore a methodology that combines static and dynamic finite element (FE) analysis, linear elastic fracture mechanics (LEFM) and experimental methods to investigate a worst-case scenario in which a previously damaged bone plate system is subjected to an impact load. Cadaver ulnas with and without midshaft dynamic compression plates are subjected to a static three-point bend test and loaded such that subcritical crack growth occurs as predicted by a hybrid method that couples LEFM and static FE. The plated and unplated bones are then unloaded and subsequently subjected to a midshaft transverse impact test. A dynamic strain-based FE model is also developed to model the midshaft transverse impact test. The average value of the impact energy required for failure was observed to be 10.53% greater for the plated set. There appears to be a trade-off between impact damage and impact resistance when ulnas are supported by fixation devices. Predictions from the dynamic FE model are shown to corroborate inferences from the experimental approach. PMID:22084055

Coates, Cameron; Goeser, Priya; Coates-Clark, Camille; Jenkins, Mark

2012-07-01

315

Nitrogen fixation in coniferous bark litter  

Microsoft Academic Search

Summary  Non-symbiotic heterotrophic N2 fixation in coniferous bark litter was investigated with the acetylene reduction assay under aerobic and anaerobic conditions. The litter studied was composed essentially of bark, of pH 5 and a C\\/N ratio of 101; the ratio of available C to available N, which governs N2 fixation, was considerably higher. The rate of N2 fixation was estimated as

Assi Weber; Veronica Sundman

1986-01-01

316

Pin loosening in external skeletal fixation  

E-print Network

styled after Journal of Biomechanica/ Engineering Kreus did not precisely document the incidence and details of complications. Towards the end of World War II, however, the high incidence of significant complications associated with external fixation... of external skeletal fixation. Following World War II, the Committee on Fracture and Trauma Surgery of the American Academy of Orthopedic Surgeons investigated the efficiency, practicality, and rightful place of external skeletal fixation. The Committee...

Vittal, Bamini

1993-01-01

317

On the similarity between pre-seismic locking and coseismic slip during the 2010 Maule earthquake (Invited)  

Microsoft Academic Search

The M8.8 Maule earthquake of 27 Feb. 2010 in Chile was the largest earthquake that ruptured a mature seismic gap in a subduction zone, monitored with a dense space-geodetic network. This provides an image of the pre-seismically locked state of the plate interface of unprecedented high resolution, allowing for an assessment of the spatial correlation of interseismic locking and coseismic

M. Moreno; M. Rosenau; D. Melnick; O. Oncken; M. Keiding; J. C. Baez; M. G. Bevis; J. Chen; A. Tassara; M. Motagh; A. Socquet; M. Cisternas; K. Bataille; H. Hase

2010-01-01

318

Methanotrophy induces nitrogen fixation during peatland development  

PubMed Central

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

Larmola, Tuula; Leppänen, Sanna M.; Tuittila, Eeva-Stiina; Aarva, Maija; Merilä, Päivi; Fritze, Hannu; Tiirola, Marja

2014-01-01

319

Methanotrophy induces nitrogen fixation during peatland development.  

PubMed

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

Larmola, Tuula; Leppänen, Sanna M; Tuittila, Eeva-Stiina; Aarva, Maija; Merilä, Päivi; Fritze, Hannu; Tiirola, Marja

2014-01-14

320

Tibial rotational osteotomy with intramedullary nail fixation  

PubMed Central

There are several theoretic advantages of using intramedullary rod fixation for tibial osteotomy fixation. We performed a retrospective review of patients who were treated with a mid-diaphyseal osteotomy of the tibia fixed with an intramedullary rod for isolated, symptomatic tibial torsion. Forty patients (59 tibias) were included in the study and were followed for a minimum of 12 months or until rod removal (average follow-up 22.6 months). Major complication rate was 8.5%, which is comparable to alternative methods of fixation. We believe that intramedullary rods are a safe alternative for fixation of tibial rotational osteotomy in patients with physeal closure. PMID:19941168

Stevens, Peter M.

2009-01-01

321

Intramedullary nail fixation of fibular fractures associated with tibial shaft and pilon fractures.  

PubMed

Treatment of distal tibial fractures is technically challenging. The purpose of this study was to evaluate the use of distally locked retrograde Ender nail fixation of axially stable fibular fractures associated with these distal tibia fractures. During a 4-year span, we treated 23 fibular fractures, associated with either distal tibial metaphyseal or articular fractures, with a retrograde 3.5-mm Ender nail. The surgical protocol along with radiographic and clinical outcomes is presented. Using this technique, we have achieved excellent fibular union with minimal complications. PMID:23609789

Stewart, Christopher M; Kiner, Dirk; Nowotarski, Peter

2013-05-01

322

Nanoscale simulations of directional locking  

E-print Network

When particles suspended in a fluid are driven through a regular lattice of cylindrical obstacles, the particle motion is usually not simply in the direction of the force, and in the high Peclet number limit particle trajectories tend to lock along certain lattice directions. By means of molecular dynamics simulations we show that this effect persists in the presence of molecular diffusion for nanoparticle flows, provided the Peclet number is not too small. We examine the effects of varying particle and obstacle size, the method of forcing, solid roughness, and particle concentration. While we observe trajectory locking in all cases, the degree of locking varies with particle size and these flows may have application as a separation technique.

J. Koplik; G. Drazer

2009-11-24

323

Nitrogen fixation method and apparatus  

DOEpatents

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.

Chen, H.L.

1983-08-16

324

Cable plates and onlay allografts in periprosthetic femoral fractures after hip replacement: laboratory and clinical observations.  

PubMed

Fractures of the femur after total hip replacement are an increasingly common and technically challenging problem. The results of nonsurgical treatment are poor. When the general condition of the patient allows, these injuries should be treated surgically. Several surgical treatments can be used to treat these fractures, and classification of the fracture assists the surgeon in the choice of procedure. Over the past decade, cable plate fixation systems and onlay strut allografts have become two of the most commonly used methods of fixation for fractures associated with hip prostheses. The ideal method of fixation is yet to be determined. However, laboratory studies have shown that dual fixation using either a lateral plate and anterior strut graft or two strut grafts produces the strongest construct. Cables rather than smooth wires should be used for fixation, and fixation strength increases with the number of cables used. The use of screws proximally produces a strong fixation but there are theoretical disadvantages to using screws around a femoral implant. Clinical data show high rates of fracture union using cable plate fixation, cortical onlay allograft fixation, and combined fixation methods for fractures that occur around well-fixed implants. Results have been less encouraging when these techniques have been used to fix fractures around prostheses that are either loose or malaligned; such fractures are better managed by revision of the femoral component to a long-stemmed device. Care should also be taken when there has been previous periosteal stripping of the femur because this may predispose to fracture nonunion. Periprosthetic fractures of the femur are a complex surgical problem and require specialized training in a range of surgical techniques. PMID:15116604

Howell, Jonathan R; Masri, Bassam A; Garbuz, Donald S; Greidanus, Nelson V; Duncan, Clive P

2004-01-01

325

Cement augmentation of intertrochanteric fracture fixation: a cadaver comparison of 2 techniques.  

PubMed

We evaluated 2 techniques of cement augmentation to enhance fixation of intertrochanteric hip fractures. 4 fixation groups with 6 cadaver femurs in each group were compared: stainless steel lag screw and side plate with and without cement augmentation and a titanium alloy expandable dome plunger and side plate with and without cement augmentation. Gauges were used to establish the mechanical behavior of intact and then fractured femurs to simple uniaxial loads. Subsequent loading to failure allowed determination of maximum fixation strengths and modes of failure. Cement augmentation of each device increased its load to failure. There was no significant difference between the cemented lag screw and the uncemented dome plunger groups with average loads to failure of 4.0 x 10(3) N. The greatest average load to failure was in the cemented dome plunger group (5.6 x 10(3) N) with the lowest in the uncemented sliding hip screw group (3.6 x 10(3) N). Device cut-out as a cause of failure occurred mostly in the uncemented lag screw group. Sliding was enhanced by those methods that increased the fixation surface area within the femoral head, unless cement encroached in the region of the barrel-screw junction. Strain analysis showed that the dome plunger unloaded the bone at the calcar, regardless of cement augmentation, while the sliding hip screw allowed for compressive stresses in this area. Proper cement augmentation increases load to failure and minimizes nail cut-out for both devices studied. However, the dome plunger, a device with a large fixation area in the femoral head, was equally effective and eliminated potential cement encroachment. Failure of intertrochanteric fracture fixation in osteoporotic bone may be minimized by an appropriate choice of device or cement augmentation. PMID:8623570

Choueka, J; Koval, K J; Kummer, F J; Zukerman, J D

1996-04-01

326

Locking and wavelength selection of an ultra-collimated single-mode diode laser bar by a volume holographic grating.  

PubMed

Wavelength-locking by a volume holographic grating (VHG) is reported for a diode laser bar with 49 single mode emitters, fitted with a dual-axis collimation phase-plate for smile elimination and excellent beam pointing correction. The much-improved VHG feedback with the ultra-collimated array beam gives 100% wavelength locking at 975 nm over a 17°C temperature range and external cavity lengths up to 110 mm. This enables a folded cavity configuration to provide a fully-locked array with wavelength selection into 200 pm channels over an 8 nm band, suitable for multi-bar dense wavelength-combining. PMID:23481984

Trela, Natalia; Baker, Howard J; Hall, Denis R

2013-02-25

327

Obituary: Martha Locke Hazen, 1931-2006  

NASA Astrophysics Data System (ADS)

Longtime Harvard Curator of Astronomical Photographs and AAVSO officer Martha Hazen passed away on 23 December 2006 at Hingham, Massachusetts, after a short illness due to acute myelogenous leukemia. One of four children of Harold Locke and Katherine (neé Salisbury) Hazen, Martha was born in Cambridge, Massachusetts, on 15 July 1931, and raised in the Town of Belmont, near Cambridge, where she lived for most of her life. Her father coined the term "servo-mechanism" while serving as an engineering professor and dean for graduate students at the Massachusetts Institute of Technology. Her mother majored in chemistry at Mount Holyoke College. After receiving an A.B. in astronomy from Mount Holyoke College in 1953, Martha earned a Ph.D. in astronomy in 1958 from the University of Michigan, defending a dissertation on the distribution of intensity in elliptical galaxies in the Virgo cluster. Martha's marriage to William Liller in 1959, and the births of two children, inevitably slowed down her progress in observational astronomy. As a research fellow of the Harvard College Observatory, Martha continued to observe two to three weeks a year in Chile, and to reduce those observations and publish the results for sixteen years. Martha's first publication, at least as far as Astrophysics Data System includes the literature, was with Alice Farnsworth on the 1952 occultations of stars by the Moon, published in the Astronomical Journal (1953). In 1958 she joined L. R. Doherty and D. H. Menzel on a short note about the calculation of line profiles in a stratified atmosphere, her only theory paper. Martha's most cited paper is "The Distribution of Intensity in Elliptical Galaxies of the Virgo Cluster," (ApJ, 132, p.306, 1960). There she acknowledges Allan Sandage for suggesting the problem and providing some of the data. Her second most cited paper is "Photometric histories of QSOs - Two QSOs with large light amplitude," (Liller, M. H. & Liller, W., ApJ (Letters), 199, p. L133-L135, 1975). Progressing to smaller objects, other frequently cited papers are on eta Carinae and spectroscopic binaries in the globular cluster M3. All of these, and most of her other papers, involve photographic photometry, mostly using archival data. In 1969, Harvard appointed Martha Curator of Astronomical Photographs, placing her in responsible charge of the world renowned Harvard Plate Archives. Under attack during the mid-1950s because it occupied too much physical space, the collection had been neglected for over a decade when Martha assumed this additional responsibility. Though she continued to observe for a few years thereafter, her stewardship of the invaluable plate archives gradually demanded her full attention, which it held until her retirement in 2002. In her thirty-three years as curator of the plate stacks, as the archive is popularly known, Martha made numerous friends in both the professional and amateur communities. Astronomical researchers on a wide variety of topics relied on her detailed knowledge of the collection to guide them to important discoveries or discovery confirmations on the old plates, and to historical understanding of results in which some detail of origin needed clarification. Martha researched and documented the characteristics of nearly a hundred separate telescopic cameras used to take the plates archived in the collection. Much of this information was ephemeral, having been passed orally from observer to observer and was in danger of passing from human memory. This was, in itself, an enormous and valuable undertaking as it ensures the utility of the plates for future research. More importantly, Martha conserved and catalogued the all important logbooks that record the date, time, and other exposure circumstances for each of the plates in the collection. The full measure of Martha's long-term contribution in this regard undoubtedly will be realized as the digitization of the entire collection of plates is completed. The Digital Access to a Sky Century from Harvard (DASCH) project will ow

Williams, Thomas R.; Willson, Lee Anne

2007-12-01

328

Circuit breaker lock out assembly  

DOEpatents

A lock out assembly for a circuit breaker which consists of a generally step-shaped unitary base with an aperture in the small portion of the step-shaped base and a roughly "S" shaped retaining pin which loops through the large portion of the step-shaped base. The lock out assembly is adapted to fit over a circuit breaker with the handle switch projecting through the aperture, and the retaining pin projecting into an opening of the handle switch, preventing removal.

Gordy, Wade T. (Jackson, SC)

1984-01-01

329

Automatic locking knee brace joint  

NASA Technical Reports Server (NTRS)

This invention is an apparatus for controlling the pivotal movement of a knee brace comprising a tang-and-clevis joint that has been uniquely modified. Both the tang and the clevis have a set of teeth that, when engaged, can lock the tang and the clevis together. In addition, the tang is biased away from the clevis. Consequently, when there is no axial force (i.e., body weight) on the tang, the tang is free to pivot within the clevis. However, when an axial force is exerted on the tang, the tang is pushed into the clevis, both sets of teeth engage, and the tang and the clevis lock together.

Weddendorf, Bruce (inventor)

1995-01-01

330

Locking mechanism for orthopedic braces  

NASA Technical Reports Server (NTRS)

An orthopedic brace locking mechanism is described which under standing or walking conditions cannot be unlocked, however under sitting conditions the mechanism can be simply unlocked so as to permit bending of the patient's knee. Other features of the device include: (1) the mechanism is rendered operable, and inoperable, dependent upon the relative inclination of the brace with respect to the ground; (2) the mechanism is automatically locked under standing or walking conditions and is manually unlocked under sitting conditions; and (3) the mechanism is light in weight and is relatively small in size.

Chao, J. I.; Epps, C. H., Jr.

1981-01-01

331

49 CFR 236.705 - Bar, locking.  

Code of Federal Regulations, 2010 CFR

...TRANSPORTATION RULES, STANDARDS, AND INSTRUCTIONS GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES...locking. A bar in an interlocking machine to which the locking dogs are...

2010-10-01

332

49 CFR 236.307 - Indication locking.  

Code of Federal Regulations, 2013 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Standards § 236.307 Indication locking. Indication locking shall be provided for operative approach...

2013-10-01

333

49 CFR 236.381 - Traffic locking.  

Code of Federal Regulations, 2014 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.381 Traffic locking. Traffic locking shall be tested when placed in service and...

2014-10-01

334

49 CFR 236.765 - Locking, mechanical.  

Code of Federal Regulations, 2013 CFR

...arrangement of locking bars, dogs, tappets, cross locking and other apparatus by means of which interlocking is effected between the levers of an interlocking machine and so interconnected that their movements must succeed each other in a...

2013-10-01

335

49 CFR 236.307 - Indication locking.  

Code of Federal Regulations, 2014 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Standards § 236.307 Indication locking. Indication locking shall be provided for operative approach...

2014-10-01

336

49 CFR 236.378 - Time locking.  

Code of Federal Regulations, 2010 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.378 Time locking. Time locking shall be tested when placed in service and...

2010-10-01

337

49 CFR 236.377 - Approach locking.  

Code of Federal Regulations, 2014 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.377 Approach locking. Approach locking shall be tested when placed in service...

2014-10-01

338

49 CFR 236.765 - Locking, mechanical.  

Code of Federal Regulations, 2011 CFR

...arrangement of locking bars, dogs, tappets, cross locking and other apparatus by means of which interlocking is effected between the levers of an interlocking machine and so interconnected that their movements must succeed each other in a...

2011-10-01

339

49 CFR 236.380 - Indication locking.  

Code of Federal Regulations, 2014 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.380 Indication locking. Indication locking shall be tested when placed in...

2014-10-01

340

49 CFR 236.381 - Traffic locking.  

Code of Federal Regulations, 2012 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.381 Traffic locking. Traffic locking shall be tested when placed in service and...

2012-10-01

341

49 CFR 236.378 - Time locking.  

Code of Federal Regulations, 2012 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.378 Time locking. Time locking shall be tested when placed in service and...

2012-10-01

342

49 CFR 236.765 - Locking, mechanical.  

Code of Federal Regulations, 2014 CFR

...arrangement of locking bars, dogs, tappets, cross locking and other apparatus by means of which interlocking is effected between the levers of an interlocking machine and so interconnected that their movements must succeed each other in a...

2014-10-01

343

49 CFR 236.381 - Traffic locking.  

Code of Federal Regulations, 2011 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.381 Traffic locking. Traffic locking shall be tested when placed in service and...

2011-10-01

344

49 CFR 236.377 - Approach locking.  

Code of Federal Regulations, 2012 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.377 Approach locking. Approach locking shall be tested when placed in service...

2012-10-01

345

49 CFR 236.378 - Time locking.  

Code of Federal Regulations, 2013 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.378 Time locking. Time locking shall be tested when placed in service and...

2013-10-01

346

49 CFR 236.378 - Time locking.  

Code of Federal Regulations, 2014 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.378 Time locking. Time locking shall be tested when placed in service and...

2014-10-01

347

49 CFR 236.377 - Approach locking.  

Code of Federal Regulations, 2013 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.377 Approach locking. Approach locking shall be tested when placed in service...

2013-10-01

348

49 CFR 236.329 - Bolt lock.  

Code of Federal Regulations, 2012 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Rules and Instructions § 236.329 Bolt lock. Bolt lock shall be so maintained that signal governing movements...

2012-10-01

349

49 CFR 236.380 - Indication locking.  

Code of Federal Regulations, 2013 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.380 Indication locking. Indication locking shall be tested when placed in...

2013-10-01

350

49 CFR 236.307 - Indication locking.  

Code of Federal Regulations, 2012 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Standards § 236.307 Indication locking. Indication locking shall be provided for operative approach...

2012-10-01

351

49 CFR 236.380 - Indication locking.  

Code of Federal Regulations, 2010 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.380 Indication locking. Indication locking shall be tested when placed in...

2010-10-01

352

49 CFR 236.329 - Bolt lock.  

Code of Federal Regulations, 2013 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Rules and Instructions § 236.329 Bolt lock. Bolt lock shall be so maintained that signal governing movements...

2013-10-01

353

49 CFR 236.329 - Bolt lock.  

Code of Federal Regulations, 2010 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Rules and Instructions § 236.329 Bolt lock. Bolt lock shall be so maintained that signal governing movements...

2010-10-01

354

49 CFR 236.381 - Traffic locking.  

Code of Federal Regulations, 2013 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.381 Traffic locking. Traffic locking shall be tested when placed in service and...

2013-10-01

355

49 CFR 236.307 - Indication locking.  

Code of Federal Regulations, 2011 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Standards § 236.307 Indication locking. Indication locking shall be provided for operative approach...

2011-10-01

356

49 CFR 236.381 - Traffic locking.  

Code of Federal Regulations, 2010 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.381 Traffic locking. Traffic locking shall be tested when placed in service and...

2010-10-01

357

49 CFR 236.377 - Approach locking.  

Code of Federal Regulations, 2010 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.377 Approach locking. Approach locking shall be tested when placed in service...

2010-10-01

358

49 CFR 236.380 - Indication locking.  

Code of Federal Regulations, 2012 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.380 Indication locking. Indication locking shall be tested when placed in...

2012-10-01

359

49 CFR 236.378 - Time locking.  

Code of Federal Regulations, 2011 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.378 Time locking. Time locking shall be tested when placed in service and...

2011-10-01

360

49 CFR 236.380 - Indication locking.  

Code of Federal Regulations, 2011 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.380 Indication locking. Indication locking shall be tested when placed in...

2011-10-01

361

49 CFR 236.329 - Bolt lock.  

Code of Federal Regulations, 2014 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Rules and Instructions § 236.329 Bolt lock. Bolt lock shall be so maintained that signal governing movements...

2014-10-01

362

49 CFR 236.329 - Bolt lock.  

Code of Federal Regulations, 2011 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Rules and Instructions § 236.329 Bolt lock. Bolt lock shall be so maintained that signal governing movements...

2011-10-01

363

49 CFR 236.377 - Approach locking.  

Code of Federal Regulations, 2011 CFR

...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.377 Approach locking. Approach locking shall be tested when placed in service...

2011-10-01

364

49 CFR 236.800 - Sheet, locking.  

Code of Federal Regulations, 2010 CFR

...TRANSPORTATION RULES, STANDARDS, AND INSTRUCTIONS GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN...APPLIANCES Definitions § 236.800 Sheet, locking. A description in tabular form of the locking operations in an...

2010-10-01

365

21 CFR 878.3250 - External facial fracture fixation appliance.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false External facial fracture fixation appliance. 878.3250...Devices § 878.3250 External facial fracture fixation appliance. (a) Identification. An external facial fracture fixation appliance is a...

2013-04-01

366

21 CFR 878.3250 - External facial fracture fixation appliance.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 false External facial fracture fixation appliance. 878.3250...Devices § 878.3250 External facial fracture fixation appliance. (a) Identification. An external facial fracture fixation appliance is a...

2014-04-01

367

Dynamic Holographic Lock-In Imaging of Ultrasonic Waves  

SciTech Connect

A laser imaging approach is presented that utilizes the adaptive property of photorefractive materials to produce a real-time measurement of ultrasonic traveling wave surface displacement and phase in all planar directions simultaneously without scanning. The imaging method performs optical lock-in operation. A single antisymmetric Lamb wave mode image produces direct quantitative determination of the phase velocity in all planar directions showing plate stiffness anisotropy. Excellent agreement was obtained with modeling calculations of the phase velocity in all planar directions for an anisotropic sheet material. The approach functions with diffusely scattering surfaces, subnanometer motions and at frequencies from Hz to GHz.

K. L. Telschow; S. K. Datta (University of Colorado); V. A. Deason (INEEL)

1999-05-01

368

APPROXIMATION OF THE BUCKLING PROBLEM FOR REISSNER-MINDLIN PLATES  

E-print Network

to be locking-free for load and vibration problems. We adapt the classical approximation theory for non, such as bridge, ship, and aircraft design. It can be formulated as a spectral problem whose solution is related applied to the plate vibration problem). However, the developed framework could be useful to

Lovadina, Carlo

369

EUREKALERT KEY WORDS Earth Science: Geology/Soil, Plate Tectonics  

E-print Network

EUREKALERT KEY WORDS Earth Science: Geology/Soil, Plate Tectonics SCINEWS KEY WORDS California against each other without giving rise to damaging quakes. The relatively smooth movement, called creep. The question of why some fault zones creep slowly and steadily while others lock for a time and then shift

370

COMPLEMENT FIXATION IN DISEASED TISSUES  

PubMed Central

An immunohistologic complement fixation test has been used in an effort to detect immune complexes in sections of kidney from rats injected with rabbit anti-rat kidney serum and in sections of biopsied kidneys from four humans with membranous glomerulonephritis. Sections of the rat and human kidneys were treated with fluorescein-conjugated anti-rabbit globulin or antihuman globulin respectively. Adjacent sections in each case were incubated first with fresh guinea pig serum and then in a second step were treated with fluorescein-conjugated antibodies against fixed guinea pig complement to detect sites of fixation of the complement. It was demonstrated that the sites of rabbit globulin in glomerular capillary walls of the rat kidneys and the sites of localized human globulin in thickened glomerular capillary walls and swollen glomerular endothelial cells of the human kidneys were the same sites in which guinea pig complement was fixed in vitro. It was concluded from these studies that rabbit nephrotoxic antibodies localize in rat glomeruli in complement-fixing antigen-antibody complexes. Furthermore, it was concluded that the deposits of human globulin in the glomeruli of the human kidneys behaved like antibody globulin in complement-fixing antigen-antibody complexes. The significance of demonstrating complement-fixing immune complexes in certain diseased tissues is discussed in regard to determination of the causative role of allergic reactions in disease. PMID:19867205

Burkholder, Peter M.

1961-01-01

371

A modelling study of vertical surface displacements at convergent plate margins  

E-print Network

of the overriding plate margin. This subsidence is reduced when roll-back takes place in a land-locked basin setting. Subduction zone roll-back due to sinking of the negatively buoyant subducting plate induces subsidence, finite element method, subduction, subsidence, uplift. 1 I N T R O D U C T I O N 1.1 Aims and approach

Buiter, Susanne

372

Eighth international congress on nitrogen fixation. Final program  

SciTech Connect

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.

Not Available

1990-12-31

373

Evaluation of the syndesmotic-only fixation for Weber-C ankle fractures with syndesmotic injury  

PubMed Central

Background: With the length of the fibula restored and the syndesmosis reduced anatomically, internal fixation using a plating device may not be necessary for supra-syndesmotic fibular fractures combined with diastasis of inferior tibio-fibular joint. A retrospective observational study was performed in patients who had this injury pattern treated with syndesmosis-only fixation. Materials and Methods: 12 patients who had Weber type-C injury pattern were treated with syndesmosis only fixation. The treatment plan was followed only if the fibular length could be restored and if the syndesmosis could be anatomically reduced. Through a percutaneous or mini-open reduction and clamp stabilization of the syndesmosis, all but one patient had a single tricortical screw fixation across the syndesmosis. Patients were kept non-weight-bearing for 6 weeks, followed by screw removal at an average of 8 weeks. Outcomes were assessed using an objective ankle scoring system (Olerud and Molander scale) and by radiographic assessment of the ankle mortise. Results: At a mean follow-up of 13 months, the functional outcome score was 75. Excellent to good outcomes were noted in 83% of the patients. Ankle mortise was reduced in all cases, and all but one fibular fracture united without loss of fixation. Six patients had more than one malleolar injury, needing either screw or anchor fixations. One patient had late diastasis after removal of the syndesmotic screw and underwent revision surgery with bone grafting of the fibula. This was probably due to early screw removal, before union of the fibular fracture had occurred. Conclusion: We recommend syndesmosis-only fixation as an effective treatment option for a combination of syndesmosis disruption and Weber type-C lateral malleolar fractures. PMID:21886929

Mohammed, R; Syed, S; Metikala, S; Ali, SA

2011-01-01

374

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...

375

3, 779801, 2006 Nitrogen fixation and  

E-print Network

BGD 3, 779­801, 2006 Nitrogen fixation and temperature E. Breitbarth et al. Title Page Abstract #12;BGD 3, 779­801, 2006 Nitrogen fixation and temperature E. Breitbarth et al. Title Page Abstract nitrogen cycle due to its significant input of atmospheric nitrogen into the ocean. Incorporating Tri

Boyer, Edmond

376

Original article The economics of nitrogen fixation  

E-print Network

Original article The economics of nitrogen fixation Steven SCHILIZZI*, David J. PANNELL Agriculture the economic value of nitrogen fixation in a Mediterranean-type farming system in Western Australia, as well bioeconomic interactions at the paddock and whole-farm levels. The value of nitrogen thus depends on its

Paris-Sud XI, Université de

377

Automatically Locking/Unlocking Orthotic Knee Joint  

NASA Technical Reports Server (NTRS)

Proposed orthotic knee joint locks and unlocks automatically, at any position within range of bend angles, without manual intervention by wearer. Includes tang and clevis, locks whenever wearer transfers weight to knee and unlocks when weight removed. Locking occurs at any angle between 45 degrees knee bend and full extension.

Weddendorf, Bruce

1994-01-01

378

Analyzing lock contention in multithreaded applications  

Microsoft Academic Search

Many programs exploit shared-memory parallelism using multithreading. Threaded codes typically use locks to coordinate access to shared data. In many cases, contention for locks reduces parallel efficiency and hurts scalability. Being able to quantify and attribute lock contention is important for understanding where a multithreaded program needs improvement. This paper proposes and evaluates three strategies for gaining insight into performance

Nathan R. Tallent; John M. Mellor-Crummey; Allan Porterfield

2010-01-01

379

49 CFR 236.742 - Dog, locking.  

Code of Federal Regulations, 2014 CFR

...Transportation 4 2014-10-01 2014-10-01 false Dog, locking. 236.742 Section 236.742 Transportation...SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.742 Dog, locking. A steel block attached to a locking bar or...

2014-10-01

380

49 CFR 236.742 - Dog, locking.  

Code of Federal Regulations, 2011 CFR

...Transportation 4 2011-10-01 2011-10-01 false Dog, locking. 236.742 Section 236.742 Transportation...SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.742 Dog, locking. A steel block attached to a locking bar or...

2011-10-01

381

49 CFR 236.742 - Dog, locking.  

Code of Federal Regulations, 2012 CFR

...Transportation 4 2012-10-01 2012-10-01 false Dog, locking. 236.742 Section 236.742 Transportation...SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.742 Dog, locking. A steel block attached to a locking bar or...

2012-10-01

382

49 CFR 236.742 - Dog, locking.  

Code of Federal Regulations, 2013 CFR

...Transportation 4 2013-10-01 2013-10-01 false Dog, locking. 236.742 Section 236.742 Transportation...SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.742 Dog, locking. A steel block attached to a locking bar or...

2013-10-01

383

Outcome after open reduction and angular stable internal fixation for supra-intercondylar fractures of the distal humerus: preliminary results with the LCP distal humerus system  

Microsoft Academic Search

Introduction  Fractures of the distal humerus are complex injuries that can be effectively treated with open reduction and internal fixation\\u000a (ORIF). The new LCP distal humerus system allows angular stable fixation of these complex fractures with anatomically preshaped\\u000a plates. The aim of the study was to evaluate operative reposition, fracture healing, and pain, function and patient satisfaction\\u000a after open reduction with

S. Greiner; N. P. Haas; H. J. Bail

2008-01-01

384

Skin damage probabilities using fixation materials in high-energy photon beams  

Microsoft Academic Search

Introduction: Patient fixation, such as thermoplastic masks, carbon-fibre support plates and polystyrene bead vacuum cradles, is used to reproduce patient positioning in radiotherapy. Consequently low-density materials may be introduced in high-energy photon beams. The aim of the this study was to measure the increase in skin dose when low-density materials are present and calculate the radiobiological consequences in terms of

Jesper Carl; Anne Vestergaard

2000-01-01

385

Standardized palmar plating of dorsally displaced distal radius fractures.  

PubMed

With the inauguration of fixed-angle plates, palmar plating has become a widely accepted way to treat dorsally displaced distal radius fractures. The technique by which the plate is applied to the radius varies. Such plates are primarily fixed either distally or at the proximal limbs. In this article, the standardized technique by which osteosynthesis is conducted in our institution is described step by step. The plate is first fixed to the shaft. Reduction is temporarily maintained by K-wires that run through the plate's distal margin. These K-wires are usually reliable in maintaining adequate reduction and are gradually replaced by locking screws in the distal row. Of 96 consecutive procedures, the duration of operation, the amount of fluoroscopy needed, and the intraoperative radiographic results are reported. Using this method, constantly good results can be achieved, even if the operation is done by less experienced surgeons. PMID:23689859

Löw, Steffen; Herold, Dirk; Eingartner, Christoph

2013-06-01

386

Dangerous Earth: A Plate Tectonic Story  

NSDL National Science Digital Library

This article and accompanying questions discusses the fact that several of the Earth's tectonic plates move at about the same speed as fingernails grow - around 35 mm per year - and that the plates are made of lithosphere (crust plus the upper part of the mantle). Students will also learn that beneath the lithosphere is the asthenosphere, part of the upper mantle that is ductile because it contains 1-10 percent molten material as films around the crystals. In addition they will find that the Earth's magnetic field has flipped (the N pole becoming the S pole, and vice versa) many times throughout geological time, resulting in rocks with varying directions of magnetism. They will also find that as tectonic plates move apart, new rock is formed and this locks in the direction of the magnetic field at the time.

387

Fixation, counting, and manipulation of heterotrophic nanoflagellates.  

PubMed

Quantitative effects of several fixatives on heterotrophic nanoflagellates (HNAN) and phototrophic nanoflagellates (PNAN) were investigated by hemacytometer and epifluorescence counting techniques. Counts of Monas sp. cultures before and after fixation with unbuffered 0.3% glutaraldehyde and 5% formaldehyde showed no loss of cells during fixation, and cell concentrations remained constant for several weeks after fixation. Buffering of fixatives with borax caused severe losses, up to 100% within 2 h. Field samples from Lake Vechten showed no decline of HNAN and total nanoflagellate concentrations for at least 1 week after fixation with 5% formaldehyde and with 1% glutaraldehyde. With 1% glutaraldehyde, the chlorophyll autofluorescence of PNAN was much brighter than with 5% formaldehyde, although it was lost after a few days and thus limited the storage time of samples. However, when primulin-stained slides were prepared soon after fixation and stored at -30 degrees C, the loss of autofluorescence was prevented and PNAN and HNAN concentrations were stable for at least 16 weeks. Effects of filtration and centrifugation on HNAN were also studied. Filtration vacuum could not exceed 3 kPa since 10 kPa already caused losses of 15 to 20%. Similar losses were caused by centrifugation, even at low speed (500 x g). PMID:16347232

Bloem, J; Bär-Gilissen, M J; Cappenberg, T E

1986-12-01

388

Performance of arm locking in LISA  

SciTech Connect

For the Laser Interferometer Space Antenna (LISA) to reach its design sensitivity, the coupling of the free-running laser frequency noise to the signal readout must be reduced by more than 14 orders of magnitude. One technique employed to reduce the laser frequency noise will be arm locking, where the laser frequency is locked to the LISA arm length. In this paper we detail an implementation of arm locking. We investigate orbital effects (changing arm lengths and Doppler frequencies), the impact of errors in the Doppler knowledge that can cause pulling of the laser frequency, and the noise limit of arm locking. Laser frequency pulling is examined in two regimes: at lock acquisition and in steady state. The noise performance of arm locking is calculated with the inclusion of the dominant expected noise sources: ultrastable oscillator (clock) noise, spacecraft motion, and shot noise. We find that clock noise and spacecraft motion limit the performance of dual arm locking in the LISA science band. Studying these issues reveals that although dual arm locking [A. Sutton and D. A. Shaddock, Phys. Rev. D 78, 082001 (2008)] has advantages over single (or common) arm locking in terms of allowing high gain, it has disadvantages in both laser frequency pulling and noise performance. We address this by proposing a modification to the dual arm-locking sensor, a hybrid of common and dual arm-locking sensors. This modified dual arm-locking sensor has the laser frequency pulling characteristics and low-frequency noise coupling of common arm locking, but retains the control system advantages of dual arm locking. We present a detailed design of an arm-locking controller and perform an analysis of the expected performance when used with and without laser prestabilization. We observe that the sensor phase changes beneficially near unity-gain frequencies of the arm-locking controller, allowing a factor of 10 more gain than previously believed, without degrading stability. With a time-delay error of 3 ns (equivalent of 1 m interspacecraft ranging error), time-delay interferometry (TDI) is capable of suppressing 300 Hz/{radical}(Hz) of laser frequency noise to the required level. We show that if no interspacecraft laser links fail, arm locking alone surpasses this noise performance for the entire mission. If one interspacecraft laser link fails, arm locking alone will achieve this performance for all but approximately 1 h per year, when the arm length mismatch of the two remaining arms passes through zero. Therefore, the LISA sensitivity can be realized with arm locking and time-delay interferometry only, without any form of prestabilization.

McKenzie, Kirk; Spero, Robert E.; Shaddock, Daniel A. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109 (United States)

2009-11-15

389

Internal fixation of an intertrochanteric femoral fracture after Birmingham hip resurfacing arthroplasty.  

PubMed

The Birmingham hip system is one of the most popular designs for hip resurfacing. Fractures associated with the Birmingham Hip Resurfacing (BHR) are mostly subcapital fractures. Other traumatic periprosthetic fractures are rarely reported. We report an intertrochanteric fracture which occurred after a Birmingham hip resurfacing. The fracture was treated with a reversed distal femoral locking plate, with a very satisfying clinical and radiological result. PMID:22697002

Carpentier, Karel; Govaers, Kris

2012-04-01

390

Plate Tectonics II: Plates, plate boundaries, and driving forces  

NSDL National Science Digital Library

The distribution of earthquakes and volcanoes around the world confirmed the theory of plate tectonics first proposed by Wegener. These phenomena also help categorize plate boundaries into three different types: convergent, divergent, and transform.

Anne Egger

2003-03-18

391

Self-locking threaded fasteners  

DOEpatents

A threaded fastener with a shape memory alloy (SMA) coatings on its threads is disclosed. The fastener has special usefulness in high temperature applications where high reliability is important. The SMA coated fastener is threaded into or onto a mating threaded part at room temperature to produce a fastened object. The SMA coating is distorted during the assembly. At elevated temperatures the coating tries to recover its original shape and thereby exerts locking forces on the threads. When the fastened object is returned to room temperature the locking forces dissipate. Consequently the threaded fasteners can be readily disassembled at room temperature but remains securely fastened at high temperatures. A spray technique is disclosed as a particularly useful method of coating of threads of a fastener with a shape memory alloy.

Glovan, Ronald J. (Butte, MT); Tierney, John C. (Butte, MT); McLean, Leroy L. (Butte, MT); Johnson, Lawrence L. (Butte, MT)

1996-01-01

392

Locking mechanism for indexing device  

DOEpatents

Disclosed is a locking mechanism for an indexing spindle. A conventional r gear having outwardly extending teeth is affixed to the spindle. Also included is a rotatably mounted camshaft whose axis is arranged in skewed relationship with the axis of the spindle. A disk-like wedge having opposing camming surfaces is eccentrically mounted on the camshaft. As the camshaft is rotated, the camming surfaces of the disc-like member are interposed between adjacent gear teeth with a wiping action that wedges the disc-like member between the gear teeth. A zero backlash engagement between disc-like member and gear results, with the engagement having a high mechanical advantage so as to effectively lock the spindle against bidirectional rotation.

Lindemeyer, Carl W. (Aurora, IL)

1984-01-01

393

Digital phase-lock loop  

NASA Technical Reports Server (NTRS)

An improved digital phase lock loop incorporates several distinctive features that attain better performance at high loop gain and better phase accuracy. These features include: phase feedback to a number-controlled oscillator in addition to phase rate; analytical tracking of phase (both integer and fractional cycles); an amplitude-insensitive phase extractor; a more accurate method for extracting measured phase; a method for changing loop gain during a track without loss of lock; and a method for avoiding loss of sampled data during computation delay, while maintaining excellent tracking performance. The advantages of using phase and phase-rate feedback are demonstrated by comparing performance with that of rate-only feedback. Extraction of phase by the method of modeling provides accurate phase measurements even when the number-controlled oscillator phase is discontinuously updated.

Thomas, Jr., Jess B. (Inventor)

1991-01-01

394

Self-locking threaded fasteners  

DOEpatents

A threaded fastener with a shape memory alloy (SMA) coatings on its threads is disclosed. The fastener has special usefulness in high temperature applications where high reliability is important. The SMA coated fastener is threaded into or onto a mating threaded part at room temperature to produce a fastened object. The SMA coating is distorted during the assembly. At elevated temperatures the coating tries to recover its original shape and thereby exerts locking forces on the threads. When the fastened object is returned to room temperature the locking forces dissipate. Consequently the threaded fasteners can be readily disassembled at room temperature but remains securely fastened at high temperatures. A spray technique is disclosed as a particularly useful method of coating of threads of a fastener with a shape memory alloy. 13 figs.

Glovan, R.J.; Tierney, J.C.; McLean, L.L.; Johnson, L.L.

1996-01-16

395

Tectonic Plates and Plate Boundaries (WMS)  

NSDL National Science Digital Library

The earths crust is constantly in motion. Sections of the crust, called plates, push against each other due to forces from the molten interior of the earth. The areas where these plates collide often have increased volcanic and earthquake activity. These images show the locations of the plates and their boundaries in the earths crust. Convergent boundaries are areas where two plates are pushing against each other and one plate may be subducting under another. Divergent boundaries have two plates pulling away from each other and indicate regions where new land could be created. Transform boundaries are places where two plates are sliding against each other in opposite directions, and diffuse boundaries are places where two plates have the same relative motion. Numerous small microplates have been omitted from the plate image. These images have been derived from images made available by the United States Geological Surveys Earthquake Hazards Program.

Eric Sokolowsky

2004-06-14

396

Stability of external skeletal fixation clamps  

E-print Network

External skeletal fixation is commonly used for treatment of many orthopedic diseases and injuries in both human and animal patients. It is mainly used for support of fractures during the healing process. Research on the loosening of transfixation...

Sandel, Mark Eugene

1995-01-01

397

Mechanistic models of oceanic nitrogen fixation  

E-print Network

Oceanic nitrogen fixation and biogeochemical interactions between the nitrogen, phosphorus and iron cycles have important implications for the control of primary production and carbon storage in the ocean. The biological ...

Monteiro, Fanny

2009-01-01

398

ORIGINAL ARTICLE Sulfur oxidizers dominate carbon fixation  

E-print Network

ORIGINAL ARTICLE Sulfur oxidizers dominate carbon fixation at a biogeochemical hot spot in the dark clade of marine gamma-proteobacterial sulfur oxidizers (GSOs) are distributed throughout proteins for sulfur oxidation (adenosine phosphosulfate reductase, sox (sulfur oxidizing system

Hansell, Dennis

399

The Biggest Plates on Earth: Plate Tectonics  

NSDL National Science Digital Library

In this lesson, students investigate the movement of Earth's tectonic plates, the results of these movements, and how magnetic anomalies present at spreading centers document the motion of the crust. As a result of this activity, students will be able to describe the motion of tectonic plates, differentiate between three types of plate boundaries, infer what type of boundary exists between two tectonic plates, and understand how magnetic anomalies provide a record of geologic history and crustal motion around spreading centers. As an example, they will also describe plate boundaries and tectonic activity in the vicinity of the Juan de Fuca plate adjacent to the Pacific Northwest coast of North America.

400

Earth's Decelerating Tectonic Plates  

Microsoft Academic Search

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

A M Forte; R Moucha; D B Rowley; S Quere; J X Mitrovica; N A Simmons; S P Grand

2008-01-01

401

Tendon and Ligament Fixation to Bone  

Microsoft Academic Search

For the successful transplantation or transposition of ligaments and tendons, fixation techniques are very important. As most\\u000a postsurgical rehabilitation protocols emphasize immediate full range of motion and early return to function, fixation must\\u000a provide adequate strength and stiffness during the early postoperative period. Table 1 lists mechanical properties (failure\\u000a load, ultimate strength, stiffness, and elastic modulus) of ligament, tendon, or

Christopher M. Hill; Yuehuei H. An; Frank A. Young

402

Fixation of Ejaculated Spermatozoa for Electron Microscopy  

Microsoft Academic Search

EJACULATED spermatozoa cannot be preserved satisfactorily by conventional fixation procedures for electron microscopy. Osmium tetroxide (OsO4) fixation of crude ejaculate consistently produces a variety of artefacts such as separation of the plasma membrane from the acrosome, widening of nuclear vacuoles, erosion of the acrosome, and swelling of mitochondria1-3. These alterations could be the consequence of the rapid destruction of the

Mario Stefanini; Cesare De Martino; Luciano Zamboni

1967-01-01

403

The lateral fixation screw in implant dentistry.  

PubMed

This clinical report presents a means of retaining implant supported superstructures using lateral fixation screws (Novadent). 244 lateral fixation screws have been used for the retention of a variety of restorations including single teeth, short span and full arch bridgework as well as overdenture bars. Over a period of observation of 4 years, the authors have found the restorations to have effective retention, ease of retrievability, good aesthetics and occlusal contours. PMID:11307389

Sethi, A; Sochor, P

2000-03-01

404

Carbon Dioxide Fixation in Cultured Animal Cells  

E-print Network

Dioxide Fixation Iii Effects of Olucose 15 Effects of Tryptophan « • 17 Effects of Insulin 18 Effects of Glucagon and Catecholamines 19 Effects of Glucocorticoids « • • • 20 Other Metabolic Pathways 25 Carbon Dioxide Fixing Enzymes 26 Beta-Me thyl... phosphate (101) to catalyze the formation of PEP from pyruvate. Oluconeogenesis will be discussed under the following headings* control of gluconeogenesis; gluconeogenesis and carbon dioxide fixation; effects of glucose, tryptophan, insulin, glucagon...

Kyner, David Smith

1969-01-01

405

Maxwellian Eye Fixation during Natural Scene Perception  

PubMed Central

When we explore a visual scene, our eyes make saccades to jump rapidly from one area to another and fixate regions of interest to extract useful information. While the role of fixation eye movements in vision has been widely studied, their random nature has been a hitherto neglected issue. Here we conducted two experiments to examine the Maxwellian nature of eye movements during fixation. In Experiment 1, eight participants were asked to perform free viewing of natural scenes displayed on a computer screen while their eye movements were recorded. For each participant, the probability density function (PDF) of eye movement amplitude during fixation obeyed the law established by Maxwell for describing molecule velocity in gas. Only the mean amplitude of eye movements varied with expertise, which was lower in experts than novice participants. In Experiment 2, two participants underwent fixed time, free viewing of natural scenes and of their scrambled version while their eye movements were recorded. Again, the PDF of eye movement amplitude during fixation obeyed Maxwell's law for each participant and for each scene condition (normal or scrambled). The results suggest that eye fixation during natural scene perception describes a random motion regardless of top-down or of bottom-up processes. PMID:23226987

Duchesne, Jean; Bouvier, Vincent; Guillemé, Julien; Coubard, Olivier A.

2012-01-01

406

Intercondylar Humerus Fracture- Parallel Plating and Its Results  

PubMed Central

Background: Intercondylar fracture of humerus is one of the commonest fractures of young adult and counts for about 30% of all elbow fractures. The treatment of these fractures continues to present challenges despite advances in internal fixation. Although orthogonal plating use to provid adequate functional results in these fractures, parallel plating is said to be mechanically more stable construct thus allowing early mobilization and better range of motion. Aim: Aim of the study is to assess the clinical as well functional results of these fractures treated with parallel plating. Study and Design: Prospective study in a tertiary care hospital. Materials and Methods: A total of 23 fresh patients of intercondylar fracture of humerus from Jan 2013 to May 2014 were included in the study and were treated with parallel plating. These patients were followed at 3, 6, 12, 24 weeks and at 1year of follow up and assessed in terms of time for union, range of motion, MAYO score, DASH score and complication rate. Results: At final follow up Mayo score was 96.32±04.96 from 5.00±01.26 and DASH SCORE was 31.42±2.04 which dropped from 150±05.34, Range of motion improved from 21.38±05.70 to 116.1±07.92 with 100% union rate and complications less than 19%. Conclusion: Parallel plating for intercondylar fracture of humerus is excellent method of fixation and results are similar to those treated with orthogonal plating. PMID:25738046

Kumar, Sanjiv; Kumar, Dharmender; Kumar, Neeraj; Verma, Reetu

2015-01-01

407

Phase-lock loop frequency control and the dropout problem  

NASA Technical Reports Server (NTRS)

Technique automatically sets the frequency of narrow band phase-lock loops within automatic lock-in-range. It presets a phase-lock loop to a desired center frequency with a closed loop electronic frequency discriminator and holds the phase-lock loop to that center frequency until lock is achieved.

Attwood, S.; Kline, A. J.

1968-01-01

408

VIEW LOOKING WEST THROUGH LOCK 70. NOTE THE EXTANT HARDWARE ...  

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

VIEW LOOKING WEST THROUGH LOCK 70. NOTE THE EXTANT HARDWARE EMBEDED IN THE TOP OF THE LOCK WALLS, THE RECESSES IN THE LOCK WALLS, AND THE LATER-ERA CONCRETE WEIR APPROXIMATELY WHERE THE LOCK GATE SHOULD BE. - New York State Barge Canal, Lockport Locks, Richmond Avenue, Lockport, Niagara County, NY

409

Cost of external fixation vs external fixation then nailing in bone infection  

PubMed Central

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

Emara, Khaled Mohamed; Diab, Ramy Ahmed; Ghafar, Khaled Abd EL

2015-01-01

410

Caribbean plate tectonics  

NSDL National Science Digital Library

This illustration available at Wikimedia Commons shows the plate tectonic setting in the Caribbean. Plate boundaries are color-coded by margin type and plate motions are noted with direction and magnitude in mm/yr.

Sting

411

Injection locking of a self-mode locking CuBr laser  

Microsoft Academic Search

A longitudinal discharge-pumped large-scale CuBr laser has been injection locked with self-mode locking CuBr laser pulse trains for the first time. High average output power of mode-locked pulses has been obtained in a wide range of delay tine between the master and slave laser by extracting energy from the slave laser. Injection locking of the green laser line and the

Jihong Geng; Yanqing Wu; Guiyan Zhang; Xiudong Song; Fucheng Lin

1994-01-01

412

Microcontroller-based locking in optics experiments  

E-print Network

Optics experiments critically require the stable and accurate locking of relative phases between light beams or the stabilization of Fabry-Perot cavity lengths. Here, we present a simple and inexpensive technique based on a stand-alone microcontroller unit to perform such tasks. Easily programmed in C language, this reconfigurable digital locking system also enables automatic relocking and sequential functioning. Different algorithms are detailed and applied to fringe locking and to low- and high-finesse optical cavity stabilization, without the need of external modulations or error signals. This technique can readily replace a number of analog locking systems advantageously in a variety of optical experiments.

K. Huang; H. Le Jeannic; J. Ruaudel; O. Morin; J. Laurat

2015-01-09

413

Microcontroller-based locking in optics experiments  

NASA Astrophysics Data System (ADS)

Optics experiments critically require the stable and accurate locking of relative phases between light beams or the stabilization of Fabry-Perot cavity lengths. Here, we present a simple and inexpensive technique based on a stand-alone microcontroller unit to perform such tasks. Easily programmed in C language, this reconfigurable digital locking system also enables automatic relocking and sequential functioning. Different algorithms are detailed and applied to fringe locking and to low- and high-finesse optical cavity stabilization, without the need of external modulations or error signals. This technique can readily replace a number of analog locking systems advantageously in a variety of optical experiments.

Huang, K.; Le Jeannic, H.; Ruaudel, J.; Morin, O.; Laurat, J.

2014-12-01

414

Interrami intraoral fixation technique for severe mandibular rifle fragmented bullet injury management.  

PubMed

Interrami intraoral Kirschner wire fixation technique is presented for the reduction, stabilization, and immobilization of a pulverized and avulsed lower jaw caused by rifle fragmented bullet injuries. This indirect mandibular war injury fixation technique was tolerated by the patients and tissue more than any indirect external fixation. In addition, it is easier than open reduction using large bone plates for disrupted ballistics mandibular injury defects. An interrami intraoral fixation is appropriate for severely disrupted mandibular hard and soft tissues, and has been adapted in cases of mass casualties and limited resources. Benefits of use include limited hospital beds and fewer follow-up visits. Rifle fragmented bullet injuries need more attention for several reasons: not only because of the higher mortality and devastating nature of the injuries, but also because these injuries are responsible for an unreported type of bullet biomechanism wounding in the craniofacial region. In turn, this necessitates specialized victim management. The survival rates depend on immediate proper execution of airway, breathing, and circulation, which become more complicated as it relates to airway compromise and oropharyngeal hemorrhage resuscitation. Survival is predicated on the implementation of feasible, sensible, life-saving techniques that are applied at the appropriate time. PMID:23851763

Shuker, Sabri T

2013-07-01

415

Green River Locks and Dams 3, 4, 5, 6 and Barren River Lock and Dam 1 Disposition, Kentucky  

E-print Network

Green River Locks and Dams 3, 4, 5, 6 and Barren River Lock and Dam 1 Disposition, Kentucky 16 September 2014 ABSTRACT: Green River Locks and Dams 3 through 6 and Barren River Lock and Dam 1 were. The Green River Locks and Dams 5 and 6 ceased operations in 1951 due to a marked decline in navigation

US Army Corps of Engineers

416

Korean Type Distal Radius Anatomical Volar Plate System: A Preliminary Report  

PubMed Central

Background Distal radius fracture is the most common fracture of the upper extremity, and approximately 60,000 distal radius fractures occur annually in Korea. Internal fixation with an anatomical volar locking plate is widely used in the treatment of unstable distal radius fractures. However, most of the currently used distal radius anatomical plate systems were designed based on the anatomical characteristics of Western populations. Recently, the Korean-type distal radius anatomical volar plate (K-DRAVP) system was designed and developed based on the anatomical characteristics of the distal radius of Koreans. The purpose of this study was to evaluate the preliminary results of the new K-DRAVP system, and to compare its radiologic and functional results with those of the other systems. Methods From March 2012 to October 2012, 46 patients with acute distal radius fractures who were treated with the K-DRAVP system at three hospitals were enrolled in this study. Standard posteroanterior and lateral radiographs were obtained to assess fracture healing, and three radiographic parameters (volar tilt, radial inclination, and radial length) were assessed to evaluate radiographic outcomes. The range of motion and grip strength, the Gartland and Werley scoring system, and the disabilities of the arm, shoulder and hand (DASH) questionnaire were used to assess clinical and functional outcomes. Results All radiologic parameters were restored to normal values, and maintained without any loosening or collapse until the time of final follow-up. Grip strength was restored to 84% of the value for the unaffected side. The mean range of motion of the wrist at final follow-up was restored to 77%-95% of the value for the unaffected side. According to the Gartland and Werley scoring system, there were 16 excellent, 26 good, and 4 fair results. The mean DASH score was 8.4 points. There were no complications after surgery. Conclusions The newly developed K-DRAVP system could be used to restore and maintain good anatomical parameters, and provide good clinical outcomes with low complication rates. This system is a promising surgical option for the treatment of distal radius fractures in the Korean population. PMID:25177449

Kim, Jeong Hwan; Kim, Jihyeung; Kim, Min Bom; Rhee, Seung Hwan; Gong, Hyun Sik; Lee, Young Ho

2014-01-01

417

Mechanical analysis of femoral neck fracture fixation with dynamic condylar screw in synthetic bone  

PubMed Central

Objective: To analyze statistically results in biomechanical testing of fixation of femoral neck Pauwels type III fractures, on synthetic bone, with dynamic condylar screw (DCS) and control group. Methods: Ten synthetic bones of a national brand were used. Test Group: fixation was performed after osteotomy at 70o tilt using DCS plate with four holes. We analyzed the resistance of this fixation with 5 mm displacement and rotational deviation (Step 1) and with10 mm (Step 2). Control group: the models were tested in their integrity until the femoral neck fracture occurred. Results: The values of the test group in Step 1 showed a mean of 974N and SD = 114N. In Stage 2, we obtained on average 1335N and SD = 98N. The values in the control group were: 1544N, 1110N, 1359N, 1194N, 1437N, respectively. Statistical analysis using the Mann-Whitney test for comparison of the maximum force (N) between the test group and the control, in Step 2, demonstrated that there is no significant difference between the DCS and control plates (p = 0.91). Conclusion: There is no significant difference between the DCS boards and the control group exposed to full resistance. Level of Evidence III, Case Control. PMID:25328435

Freitas, Anderson; Maciel, Rafael Almeida; Lima, Renato De Almeida; Souto, Diogo Ranier De Macedo; Ferrer, Marcelo De Almeida

2014-01-01

418

Numerical investigation of mechanical effects caused by various fixation positions on a new radius intramedullary nail.  

PubMed

Fracture of the radius diaphysis is an unusual injury in adults. Open reduction and plate osteosynthesis has been recommended by most of the authors. However, this trend has started to change with the recent introduction of newly designed interlocking intramedullary (IM) nails. New generation of IM nails are developed in order to utilise the advantages of IM nails against plates. Because of its anatomical structure, the radius bone has a complex geometry. Therefore, the callus structure, which forms during the healing period, should not be affected from external effects, such as excessive loads or motion. In this study, effects of radial styloid process (RSP), dorsal side and ulnar notch edge fixations of a new design radius IM nail on the healing period were numerically investigated. A three-dimensional solid model of radius was obtained from computed tomography images of a volunteer and callus structure model, was placed accordingly and different fixations of implants were performed. The models were analysed under axial loads transferring from the wrist to the radius bone using finite element method. As a result of the analysis, fixation of IM nail from RSP was found to be beneficial on healing period in terms of both callus motion and emerging stresses. PMID:23682815

Çelik, A; Kovac?, H; Saka, G; Kaymaz, ?

2015-01-01

419

Digital phase-locked loop  

NASA Technical Reports Server (NTRS)

An digital phase-locked loop is provided for deriving a loop output signal from an accumulator output terminal. A phase detecting exclusive OR gate is fed by the loop digital input and output signals. The output of the phase detector is a bi-level digital signal having a duty cycle indicative of the relative phase of the input and output signals. The accumulator is incremented at a first rate in response to a first output level of the phase detector and at a second rate in response to a second output level of the phase detector.

Cliff, R. A. (inventor)

1975-01-01

420

Locking mechanism for orthopedic braces  

NASA Technical Reports Server (NTRS)

A locking mechanism for orthopedic braces is described which automatically prevents or permits the relative pivotable movement between a lower brace member and an upper brace member. The upper and lower brace members are provided with drilled bores within which a slidable pin is disposed, and depending upon the inclination of the brace members with respect to a vertical plane, the slidable pin will be interposed between both brace members. The secondary or auxiliary latching device includes a spring biased, manually operable lever bar arrangement which is manually unlatched and automatically latched under the influence of the spring.

I-Lechao, J.; Epps, C. H., Jr. (inventors)

1976-01-01

421

[Visual fixation features after treatment of exudative age macular degeneration].  

PubMed

Changes of visual fixation in patients with choroidal neovascularitation (CNV) associated with age macular degeneration (AMD) after bevacizumab are studied. 45 patients (45 eyes) with active CNV treated with intravitreal bevacizumab were enrolled into the study. Visual fixation was studied before and 3-6 months after treatment using original method that included fundus foto and fluorescein angiography. Fixation relative to fovea and lesion was evaluated. Foveal fixation beyond lesion was found in 9%, foveal fixation within lesion--in 47%, extrafoveal fixation beyond lesion--in 18%, extrafoveal fixation within lesion--in 26% of patients. Changes of fixation localization after treatment was found in 24% patients. Examination of visual fixation may be useful for prognosis of anti-VEGF treatment efficacy in patients with CNV. PMID:21721271

Surguch, V K; Surnina, Z V; Sizova, M V

2011-01-01

422

89. LOCK 13 EAST. WOODEN TIMBERS (FOREGROUND LEFT AND RIGHT ...  

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

89. LOCK 13 EAST. WOODEN TIMBERS (FOREGROUND LEFT AND RIGHT OF LOCK ENTRANCE) ARE BEING USED AS BUMPERS TO HELP GUIDE SHIP INTO LOCK WHILE AVOIDING CONTACT WITH WALLS. - Morris Canal, Phillipsburg, Warren County, NJ

423

30 CFR 57.12068 - Locking transformer enclosures.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Locking transformer enclosures. 57.12068 Section 57.12068...Electricity Surface Only § 57.12068 Locking transformer enclosures. Transformer enclosures shall be kept locked against...

2010-07-01

424

30 CFR 56.12068 - Locking transformer enclosures.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Locking transformer enclosures. 56.12068 Section 56.12068...MINES Electricity § 56.12068 Locking transformer enclosures. Transformer enclosures shall be kept locked against...

2010-07-01

425

30 CFR 56.12068 - Locking transformer enclosures.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Locking transformer enclosures. 56.12068 Section 56.12068...MINES Electricity § 56.12068 Locking transformer enclosures. Transformer enclosures shall be kept locked against...

2012-07-01

426

30 CFR 56.12068 - Locking transformer enclosures.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Locking transformer enclosures. 56.12068 Section 56.12068...MINES Electricity § 56.12068 Locking transformer enclosures. Transformer enclosures shall be kept locked against...

2011-07-01

427

30 CFR 57.12068 - Locking transformer enclosures.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Locking transformer enclosures. 57.12068 Section 57.12068...Electricity Surface Only § 57.12068 Locking transformer enclosures. Transformer enclosures shall be kept locked against...

2011-07-01

428

30 CFR 57.12068 - Locking transformer enclosures.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Locking transformer enclosures. 57.12068 Section 57.12068...Electricity Surface Only § 57.12068 Locking transformer enclosures. Transformer enclosures shall be kept locked against...

2013-07-01

429

30 CFR 57.12068 - Locking transformer enclosures.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Locking transformer enclosures. 57.12068 Section 57.12068...Electricity Surface Only § 57.12068 Locking transformer enclosures. Transformer enclosures shall be kept locked against...

2012-07-01

430

30 CFR 56.12068 - Locking transformer enclosures.  

Code of Federal Regulations, 2014 CFR

...2014-07-01 2014-07-01 false Locking transformer enclosures. 56.12068 Section 56.12068...MINES Electricity § 56.12068 Locking transformer enclosures. Transformer enclosures shall be kept locked against...

2014-07-01

431

30 CFR 57.12068 - Locking transformer enclosures.  

Code of Federal Regulations, 2014 CFR

...2014-07-01 2014-07-01 false Locking transformer enclosures. 57.12068 Section 57.12068...Electricity Surface Only § 57.12068 Locking transformer enclosures. Transformer enclosures shall be kept locked against...

2014-07-01

432

30 CFR 56.12068 - Locking transformer enclosures.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Locking transformer enclosures. 56.12068 Section 56.12068...MINES Electricity § 56.12068 Locking transformer enclosures. Transformer enclosures shall be kept locked against...

2013-07-01

433

UPSTREAM LOCK GATE DETAIL AND DOG HOUSE. NOTE ARM AND ...  

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

UPSTREAM LOCK GATE DETAIL AND DOG HOUSE. NOTE ARM AND GEARING FOR CONTROLLING LOCK GATE. LOOKING WEST SOUTHWEST. - Illinois Waterway, Brandon Road Lock and Dam , 1100 Brandon Road, Joliet, Will County, IL

434

DOWNSTREAM LOCK GATE DETAIL VIEW WITH DOG HOUSE. NOTE CONTROL ...  

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

DOWNSTREAM LOCK GATE DETAIL VIEW WITH DOG HOUSE. NOTE CONTROL ARM AND GEAR FOR GATE. LOOKING NORTHWEST. - Illinois Waterway, Dresden Island Lock and Dam , 7521 North Lock Road, Channahon, Will County, IL

435

Past, Present, Future Erosion at Locke Island  

SciTech Connect

This report describes and documents the erosion that has occurred along the northeast side of Locke Island over the last 10 to 20 years. The principal cause of this erosion is the massive Locke Island landslide complex opposite the Columbia River along the White Bluffs, which constricts the flow of the river and deflects the river's thalweg southward against the island.

Bjornstad, Bruce N.

2006-08-08

436

Self-Injection Locking Of Diode Lasers  

NASA Technical Reports Server (NTRS)

Simple optical coupling scheme locks array of gain-guided diode lasers into oscillation in single mode and with single-lobed output beam. Selective feedback from thin etalon self-injection-locks array into desired mode. One application of new scheme for pumping of neodymium: yttrium aluminum garnet lasers with diode-laser arrays.

Hemmati, H.

1991-01-01

437

Phase-locking lasers with phase conjugation  

SciTech Connect

Techniques are described for phase locking two or more lasers using phase-conjugating mirrors. Any changes in the optical cavity length or in the spatial mode structure of the optical beams are automatically compensated. Two argon-ion lasers were locked using a photorefractive crystal of BaTiO/sub 3/ acting as a self-pumped phase-conjugating mirror.

Feinberg, J.; Bacher, G.D.

1986-03-03

438

49 CFR 236.793 - Rod, lock.  

Code of Federal Regulations, 2014 CFR

...APPLIANCES Definitions § 236.793 Rod, lock. A rod, attached to the front rod or lug of a switch, movable-point frog or derail, through which a locking plunger may extend when the switch points or derail are in the normal or reverse...

2014-10-01

439

49 CFR 236.793 - Rod, lock.  

Code of Federal Regulations, 2011 CFR

...APPLIANCES Definitions § 236.793 Rod, lock. A rod, attached to the front rod or lug of a switch, movable-point frog or derail, through which a locking plunger may extend when the switch points or derail are in the normal or reverse...

2011-10-01

440

49 CFR 236.793 - Rod, lock.  

Code of Federal Regulations, 2012 CFR

...APPLIANCES Definitions § 236.793 Rod, lock. A rod, attached to the front rod or lug of a switch, movable-point frog or derail, through which a locking plunger may extend when the switch points or derail are in the normal or reverse...

2012-10-01

441

49 CFR 236.793 - Rod, lock.  

Code of Federal Regulations, 2013 CFR

...APPLIANCES Definitions § 236.793 Rod, lock. A rod, attached to the front rod or lug of a switch, movable-point frog or derail, through which a locking plunger may extend when the switch points or derail are in the normal or reverse...

2013-10-01

442

Robust quantum data locking from phase modulation  

E-print Network

Quantum data locking is a unique quantum phenomenon that allows a relatively short key to (un)lock an arbitrarily long message encoded in a quantum state, in such a way that an eavesdropper who measures the state but does not know the key has essentially no information about the encrypted message. The application of quantum data locking in cryptography would allow one to overcome the limitations of the one-time pad encryption, which requires the key to have the same length as the message. However, it is known that the strength of quantum data locking is also its Achilles heel, as the leakage of a few bits of the key or the message may in principle allow the eavesdropper to unlock a disproportionate amount of information. In this paper we show that there exist quantum data locking schemes that can be made robust against information leakage by increasing the length of the shared key by a proportionate amount. This implies that a constant size key can still encrypt an arbitrarily long message as long as a fraction of it remains secret to the eavesdropper. Moreover, we greatly simplify the structure of the protocol by proving that phase modulation suffices to generate strong locking schemes, paving the way to optical experimental realizations. Also, we show that successful data locking protocols can be constructed using random codewords, which very well could be helpful in discovering random codes for data locking over noisy quantum channels.

Cosmo Lupo; Mark M. Wilde; Seth Lloyd

2014-08-29

443

An automatic mode-locked system for passively mode-locked fiber laser  

NASA Astrophysics Data System (ADS)

This paper designs and implements one kind of automatic mode-locked system. It can adjust a passively mode-locked fiber laser to keep steady mode-locked states automatically. So the unsteadiness of traditional passively mode-locked fiber laser can be avoided. The system transforms optical signals into electrical pulse signals and sends them into MCU after processing. MCU calculates the frequency of the signals and judges the state of the output based on a quick judgment algorithm. A high-speed comparator is used to check the signals and the comparison voltage can be adjusted to improve the measuring accuracy. Then by controlling two polarization controllers at an angle of 45degrees to each other, MCU extrudes the optical fibers to change the polarization until it gets proper mode-locked output. So the system can continuously monitor the output signal and get it back to mode-locked states quickly and automatically. States of the system can be displayed on the LCD and PC. The parameters of the steady mode-locked states can be stored into an EEPROM so that the system will get into mode-locked states immediately next time. Actual experiments showed that, for a 6.238MHz passively mode-locked fiber lasers, the system can get into steady mode-locked states automatically in less than 90s after starting the system. The expected lock time can be reduced to less than 20s after follow up improvements.

Li, Sha; Xu, Jun; Chen, Guoliang; Mei, Li; Yi, Bo

2013-12-01

444

Strategies for surgical approaches in open reduction internal fixation of pilon fractures.  

PubMed

Pilon or tibial plafond fractures usually result from high-energy injuries with rotation and/or axial compression. They occur in an area of relatively poor soft tissue coverage and frequently present a surgical challenge in deciding which incisions will be best for performing open reduction internal fixation. A variety of anterior and posterior approaches have been described based on the ease of fracture reduction and internal fixation with plates. Some of the incisions are fracture specific, that is, planned for a limited approach to the pilon. But in more complex cases, a wider exposure is indicated and thus more extensile approaches, both anterior and posterior, can be valuable. This review article will describe the different surgical approaches, focusing on their indication and technique. PMID:25072286

Assal, Mathieu; Ray, Adrien; Stern, Richard

2015-02-01

445

Sputtering and ion plating  

NASA Technical Reports Server (NTRS)

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.

1972-01-01

446

Copper Map Plate Detail  

USGS Multimedia Gallery

A portion of the engraving on the plate used to print points, lines, and text in black ink. Engravings on the plate are left-to-right reversed. This plate was cleaned and treated to improve the visibility of the engraving. The plate was used to print the Washington [D.C.] and vicinity, 1:31,680-sca...

447

Plate Tectonics Animation  

NSDL National Science Digital Library

Plate tectonics describes the behavior of Earth's outer shell, with pieces (plates) bumping and grinding and jostling each other about. Explore these maps and animations to get a jump start on understanding plate tectonic processes, history, and how motion of the plates affects our planet today.

2002-01-01

448

Planet Earth: Plate Tectonics  

E-print Network

, ice and sediment for long periods of geological time (>105 a). · Controlled and passive (e-plate system #12;Relative plate motions on a sphere A In a three-plate system, A, B and C, if AB and BC are known then CA can be found. See GG p23-24. Euler's theorem: motion of any spherical plate can

Watts, A. B. "Tony"

449

Lock for an oil field valve  

SciTech Connect

A locking device is described for oil field valves or the like including: a lock base member having a recessed portion extending from a bottom surface of the base member. The recessed portion is configured to fit over a valve flange and to a body of a valve. An opening in the base member extends through the base member so that when the base member is located on a valve body, a valve stem of a valve can project through the base member and be manipulated with the base member in position on a valve body. At least two first locking bores extend downwardly from an upper surface of the base member. At least two second locking bores extend inwardly from the respective sides of the base member and partially intersect the locking bores.

Michon, J.M.

1987-05-05

450

Mechanical analysis of a rodent segmental bone defect model: the effects of internal fixation and implant stiffness on load transfer.  

PubMed

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. PMID:24882739

Yavari, S Amin; van der Stok, J; Ahmadi, S M; Wauthle, R; Schrooten, J; Weinans, H; Zadpoor, A A

2014-08-22

451

Rapid Two-Temperature Formalin Fixation  

PubMed Central

Formalin fixation is a mainstay of modern histopathologic analysis, yet the practice is poorly standardized and a significant potential source of preanalytical errors. Concerns of workflow and turnaround time drive interest in developing shorter fixation protocols, but rapid protocols can lead to poor histomorphology or inadequate downstream assay results. Additionally, assays such as immunohistochemistry for phosphorylated epitopes have historically been challenging in the context of formalin-fixed tissue, indicating that there may be room for improvement in this process that is fundamental to the practice of anatomic pathology. With these issues in mind, we studied basic formalin biochemistry to develop a novel formalin fixation protocol that involves a pre-incubation in subambient temperature formalin prior to a brief exposure to heated formalin. This new protocol is more rapid than standard protocols yet preserves histomorphology and yields tissue that is compatible with an expanded set of downstream clinical and research assays, including immunohistochemistry for phosphorylated epitopes. PMID:23349806

Roberts, Esteban; Borlee, Grace; Otter, Michael; Baird, Geoffrey S.

2013-01-01

452

Biometric recognition via fixation density maps  

NASA Astrophysics Data System (ADS)

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.

Rigas, Ioannis; Komogortsev, Oleg V.

2014-05-01

453

Mapping Plate Tectonic Boundaries  

NSDL National Science Digital Library

To prepare for this activity, students do background reading on Plate Tectonics from the course textbook. Students also participate in a lecture on the discovery and formulation of the unifying theory of plate tectonics, and the relationship between plate boundaries and geologic features such as volcanoes. Lastly, in lecture, students are introduced to a series of geologic hazards caused by certain plate tectonic interactions. The activity gives students practices at identifying plate boundaries and allows them to explore lesser known tectonically active regions.

Michael Kerwin

454

Evolution of mesh fixation for hernia repair.  

PubMed

Hernia repair remains one of the most common surgical procedures performed around the world. Over the past several decades, in response to various mesh-related complications and coinciding with the influx of laparoscopy into the field of general surgery, numerous advancements have been made in regards to the technology of mesh products being used in hernia repair today. Along these same lines, devices used for mesh fixation have evolved at a similar pace. The goal of this chapter is to review the various materials and methods of mesh fixation being utilized in both ventral and inguinal hernia repair today. PMID:25398127

Webb, David; Stoikes, Nathaniel; Voeller, Guy

2014-11-01

455

MICROBIOLOGY: A Fifth Pathway of Carbon Fixation  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required. Genome sequence analyses and enzymatic studies reveal a novel CO2 fixation cycle in some autotrophic archaea. Autotrophs are organisms that can grow using carbon dioxide (CO2) as their sole source of carbon. Four mechanisms are known by which autotrophic organisms fix carbon. Berg et al. describe a fifth autotrophic CO2 fixation pathway in archaea that may have been used by some of the earliest organisms on Earth.

Rudolf K. Thauer (Max Planck Institute for Terrestrial Microbiology; )

2007-12-14

456

Improved finite strip Mindlin plate bending element using assumed shear strain distributions  

NASA Technical Reports Server (NTRS)

A linear finite strip plate element based on Mindlin/Reissner plate theory is developed. The analysis is suitable for both thin and thick plates. In the formulation new transverse shear strains are introduced and assumed constant in each two-code linear strip. The element stiffness matrix is explicitly formulated for efficient computation and computer implementation. Numerical results showing the efficiency and predictive capability of the element for the analysis of plates are presented for different support and loading conditions and a wide range of thicknesses. No sign of shear locking phenomenon was observed with the newly developed element.

Chulya, Abhisak; Thompson, Robert L.

1988-01-01

457

Surgical Strategies to Improve Fixation in the Osteoporotic Spine: The Effects of Tapping, Cement Augmentation, and Screw Trajectory  

PubMed Central

Study Design?Biomechanical study of pedicle screw fixation in osteoporotic bone. Objective?To investigate whether it is better to tap or not tap osteoporotic bone prior to placing a cement-augmented pedicle screw. Methods?Initially, we evaluated load to failure of screws placed in cancellous bone blocks with or without prior tapping as well as after varying the depths of tapping prior to screw insertion. Then we evaluated load to failure of screws placed in bone block models with a straight-ahead screw trajectory as well as with screws having a 23-degree cephalad trajectory (toward the end plate). These techniques were tested with nonaugmented (NA) screws as well as with bioactive cement (BioC) augmentation prior to screw insertion. Results?In the NA group, pretapping decreased fixation strength in a dose-dependent fashion. In the BioC group, the tapped screws had significantly greater loads to failure (p?fixation is often inadequate in the osteoporotic spine, but this study suggests tapping prior to cement augmentation will substantially improve fixation when compared with not tapping. Angulating screws more cephalad also seems to enhance aging spine fixation. PMID:24494181

Kuhns, Craig A.; Reiter, Michael; Pfeiffer, Ferris; Choma, Theodore J.

2013-01-01

458

Surgical strategies to improve fixation in the osteoporotic spine: the effects of tapping, cement augmentation, and screw trajectory.  

PubMed

Study Design?Biomechanical study of pedicle screw fixation in osteoporotic bone. Objective?To investigate whether it is better to tap or not tap osteoporotic bone prior to placing a cement-augmented pedicle screw. Methods?Initially, we evaluated load to failure of screws placed in cancellous bone blocks with or without prior tapping as well as after varying the depths of tapping prior to screw insertion. Then we evaluated load to failure of screws placed in bone block models with a straight-ahead screw trajectory as well as with screws having a 23-degree cephalad trajectory (toward the end plate). These techniques were tested with nonaugmented (NA) screws as well as with bioactive cement (BioC) augmentation prior to screw insertion. Results?In the NA group, pretapping decreased fixation strength in a dose-dependent fashion. In the BioC group, the tapped screws had significantly greater loads to failure (p?fixation is often inadequate in the osteoporotic spine, but this study suggests tapping prior to cement augmentation will substantially improve fixation when compared with not tapping. Angulating screws more cephalad also seems to enhance aging spine fixation. PMID:24494181

Kuhns, Craig A; Reiter, Michael; Pfeiffer, Ferris; Choma, Theodore J

2014-02-01

459

Mode-locked frequency doubled Nd:YAG laser  

NASA Technical Reports Server (NTRS)

The design, fabrication, test, and delivery of two mode-locked, frequency doubled Nd:YAG laser systems are described. Each system was comprised of two units, the laser head and optics on an Invar plate and the electronics control unit in a relay rack chassis panel. Laser number one operated at a repetition rate of 400 MHz and was designed for use in an optical communication system. Laser number two operated at 200 MHz repetition rate and was designed for optical ranging and target signature experiments. Both lasers had a pulse width of 200 ps at the 10% amplitude points at 1.064 micrometer wavelength (150 ps at 0.532 micrometers) with an amplitude stability of + or - 4%. Output power exceeded the design goals.

Brookman, J. S.

1976-01-01

460

Finite element analysis of three patterns of internal fixation of fractures of the mandibular condyle.  

PubMed

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. PMID:22981343

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

2013-06-01

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