Cm Of Displacement Research Articles

Constraints on the 2013 Saravan intraslab earthquake using permanent GNSS, InSAR and seismic data

SUMMARY On 16 April 2013, an Mw = 7.7 earthquake struck the border of Iran and Pakistan in the central part of the Makran subduction zone with a reported depth of 80 km by USGS. This rare event in this poorly instrumented region helps to shed light on the kinematics of the subducting slab. We investigate source parameters of the Saravan intraslab normal earthquake using RADARSAT-2 SAR images in three ascending tracks, nine permanent GNSS sites and teleseismic data. The maximum coseismic displacement occurred at the SRVN GNSS station with 54.1 mm southeast horizontal and 42.7 mm upward vertical displacements. The coseismic ascending InSAR displacement maps illustrate a continuous and smooth NE-trending elliptical shape deformation pattern with a maximum of ∼29 cm of displacement away from the satellite. We use 25 broad-band teleseismic P-waveforms to estimate the focal mechanism of the main shock. A joint uniform inversion of InSAR, GNSS and teleseismic data reveals a NW-dipping SW-striking fault and a primarily normal-faulting earthquake with a minor right-lateral strike-slip component. The static slip distribution of the InSAR coseismic maps localizes variable slip at depths between 50 and 81 km with a maximum amplitude >3 m at 60–75.5 km depth, rupturing the oceanic crust of the subducted slab. The kinematic slip distribution exhibits a well-constrained slip pattern with a nucleation depth of 65 km. The source time function indicates that the earthquake reaches its maximum moment tensor release at ∼8 and ∼16 s. The NE-trend of the Saravan earthquake slip pattern, the orientation of the volcanic arc, and the distribution of the intraslab intermediate-depth normal earthquakes provide new insights into slab geometry in the central Makran subduction zone. We suggest that the slab bending at the hinge of subducting Arabian Plate is oblique along a NE–SW direction parallel to the volcanic arc rather than the shoreline or deformation front, and it is likely to be the reason for an oblique volcanic arc in the Makran subduction zone. These new constraints on the Makran slab geometry will help further studies in establishing realistic coupling maps for seismic hazard assessment.

Chronic Ischial Avulsion Fracture Excision With Primary Proximal Hamstring Repair: A Technique

Ischial avulsion fractures classically occur in the pediatric population and are relatively uncommon. These injuries are treated conservatively; however, in cases where there is greater than 2 cm of displacement, surgical intervention is recommended. In some cases, displaced fractures are either misdiagnosed or proper treatment is neglected, and patients who transition into adulthood are left with chronic nonunions that can become a source of pain and disability. Here we present a surgical technique for a chronic ischial avulsion fracture nonunion that is excised, and the hamstring tendons are then primarily repaired to the ischium using suture anchors.

Maximizing mechanical advantage: surgical technique increases stiffness in spinal instrumentation.

While there has been a great improvement in the treatment of adolescent idiopathic scoliosis, sagittal deformity correction has remained challenging. Increased rod stiffness has been shown to reduce thoracic flattening. We propose that the surgical technique can increase rod stiffness. A mechanical study was created to quantify the effect this has on construct stiffness. The sagittal bending stiffness of a constrained over contoured rod was measured using four different commonly used instrumentation systems. Pedicle screws were secured into custom printed blocks. One block was completely immobilized, while the other block was subject to four levels of constraint. This includes no constraint, mild constraint, moderate constraint, and maximal constraint with both blocks immobilized. The rod apex was loaded until 1cm of displacement occurred. The stiffness was then calculated and compared between groups. All four rod types showed increased bending stiffness as the construct became more constrained. The moderately constrained and the maximally constrained groups had a significantly higher stiffness compared to the unconstrained groups in all rod types (p < 0.05). The 6.0mm titanium circular rods showed the highest increase in stiffness between maximal and no constraint, which became 3.02 × stiffer. Rod stiffness is not only determined by size, shape, and metal alloy, but also by surgical technique. Constraining the spinal instrumentation by first locking the rod to the proximal and distal anchors significantly increases the sagittal bending stiffness. In a mechanical model this technique increases rod bending stiffness regardless of the material or shape.

Biomechanical comparison of tenorrhaphy constructs for tendon reconstructions and transfers

With tendon transfers or reconstructions, the tenorrhaphy must be strong enough to withstand early mobilization in the immediate postoperative period to decrease adhesion formation and optimize functional outcomes. The purpose of this study was to compare the strength, bulk, and gliding resistance of four common tendon-to-tendon attachment constructs. A biomechanical study was performed utilizing 80 cadaveric tendons to compare four common tendon tenorrhaphy constructs: the end-weave (EW); Pulvertaft (PT); single-pass, side-to-side (SP-STS); and simple, side-to-side (STS) attachments. The primary outcome measures investigated included tenorrhaphy morphology, gliding resistance, tensile strength, and deformation at failure of the different constructs. A total of 40 tendon pairs, 10 per repair group, were constructed, biomechanically evaluated, and outcomes were compared. There were no significant differences in the cross-sectional area of the native tendon (p = 0.334) or repair site (p = 0.564) and no difference in the added bulk of the repair (p = 0.663) between the repair groups. Gliding resistance was not significantly different between the repair groups (p = 0.110). The SP-STS repair was significantly stronger (p < 0.001), stiffer (p < 0.001), and exhibited less displacement at peak load (p = 0.004), and greater force generation at 1 cm of displacement (p = 0.002) compared to the other constructs. The SP-STS is significantly stronger, without a significant difference in bulk and gliding resistance compared to the PT, EW, STS repairs. SP-STS can be utilized in tendon transfers and reconstructions to safely permit early active mobilization.

The Lateral Stress Radiograph Identifies Occult Instability of Lateral Compression Pelvic Ring Injuries Without Sedation.

To determine if pelvic ring displacement on the lateral stress radiograph (LSR) correlated with displacement on examination under anesthesia (EUA). Retrospective cohort study. Urban Level I trauma center. Twenty consecutive patients with unilateral minimally displaced LC1 injuries with complete sacral fractures. An anteroposterior pelvis radiograph taken in the lateral decubitus position (LSR) was performed on awake patients before EUA in the operating room. Correlation between ≥1 cm of pelvic ring displacement on the LSR and EUA. The LSR demonstrated ≥1 cm of displacement in 11 of the 20 patients (55%). All of these patients had ≥1 cm of displacement on EUA and underwent surgical fixation. The remaining 9 patients with <1 cm of displacement on the LSR also had <1 cm of displacement on EUA and were managed nonoperatively. The LSR reliably identified occult instability in LC1 pelvic ring injuries and demonstrated 100% correlation with EUA. In contrast to EUA, the LSR does not require sedation and normalizes the amount of force applied to determine instability. Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Comparison of Locked Plating of Varus Displaced Proximal Humeral Fractures With and Without Fibula Allograft Augmentation.

To compare the clinical and radiographic outcomes between patients treated with fibula allograft-augmented locking compression fixation and patients treated with locking compression fixation alone for 2- and 3-part proximal humeral fractures with varus displacement. Retrospective review. Level 1 trauma center. One hundred two patients treated with locking plate fixation ± fibular allograft augmentation confirmed intraoperatively by visual inspection to have varus-angulated, 2- and 3-part proximal humerus fractures with at least 45 degrees of varus angulation at the neck/shaft and at least 1 cm of displacement. Proximal humerus locking plate (PHILOS; Synthes, Paoli, PA) with or without fibula allograft augmentation. Statistical analysis to determine the differences between fractures treated with locking compression fixation ± fibula allograft augmentation regarding complications, shoulder reported outcome measures, and patient ROMs (Visual Analog Score (VAS), Disabilities of the Arm, Shoulder and Hand, and Simple Shoulder Test scores). Medical comorbidities as potential risk factors for complication from surgery were also evaluated. Of 102 surgical cases, 27 were augmented with fibula allograft and 75 were not. Postoperatively, there were 16 noncatastrophic varus collapses of the fracture, 6 catastrophic varus collapses, and 5 deaths. Addition of fibula allograft did not significantly affect postoperative varus collapse, shoulder ROM, pain, or PROMs. Addition of fibula allograft to patients sustaining varus-angulated, 2- and 3-part proximal humeral fractures conferred no benefit to patient outcomes at our institution. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

In situ measurements of the ice flow motion at Eqip Sermia Glacier using a remotely controlled unmanned aerial vehicle (UAV)

Abstract. Measuring the ice flow motion accurately is essential to better understand the time evolution of glaciers and ice sheets and therefore to better anticipate the future consequence of climate change in terms of sea level rise. Although there are a variety of remote sensing methods to fill this task, in situ measurements are always needed for validation or to capture high-temporal-resolution movements. Yet glaciers are in general hostile environments where the installation of instruments might be tedious and risky when not impossible. Here we report the first-ever in situ measurements of ice flow motion using a remotely controlled unmanned aerial vehicle (UAV). We used a quadcopter UAV to land on a highly crevassed area of Eqip Sermia Glacier, West Greenland, to measure the displacement of the glacial surface with the aid of an onboard differential GNSS receiver. We measured approximately 70 cm of displacement over 4.36 h without setting foot onto the glacier – a result validated by applying UAV photogrammetry and template matching techniques. Our study demonstrates that UAVs are promising instruments for in situ monitoring and have great potential for capturing continuous ice flow variations in inaccessible glaciers – a task that remote sensing techniques can hardly achieve.

Deformation associated with sliver transport in Costa Rica: seismic and geodetic observations of the July 2016 Bijagua earthquake sequence

SUMMARYTectonic slivers form in the overriding plate in regions of oblique subduction. The inner boundaries of the sliver are often poorly defined and can consist of well-defined faults, rotating blocks or diffuse fault systems, which pass through or near the volcanic arc. The Guanacaste Volcanic Arc Sliver (GVAS) as defined by Montero et al., is a segment of the Central American Forearc Sliver, whose inner boundary is the ∼87-km-long Haciendas-Chiripa fault system (HCFS), which is located ∼10 km behind the volcanic arc and consists of strike slip faults and pull apart steps. We characterize the current ground motion on this boundary by combining earthquake locations and focal mechanisms of the 2016 Bijagua earthquake sequence, with the surface ground deformation obtained from Interferometric Synthetic Aperture Radar (InSAR) images from the ALOS-2 satellite. The coseismic stack of interferograms show ∼6 cm of displacement towards the line of sight of the satellite between the Caño Negro fault and the Upala fault, indicating uplift or SE horizontal surface displacement. The largest recorded earthquake of the sequence was Mw 5.4, and the observed deformation is one of the smallest earthquakes yet detected by InSAR in the Central American region. Forward and inverse models show the surface deformation can be partially explained by slip on a single fault, but it can be better explained by slip along two faults linked at depth. The best-fitting model consists of 0.33 m of right lateral slip on the Caño Negro fault and 0.35 m of reverse slip on the Upala fault, forming a positive flower structure. As no reverse seismicity was recorded, we infer the slip on the Upala fault occurred aseismically. Observations of the Bijagua earthquake sequence suggests the forearc sliver boundary is a complex and diffuse fault system. There are localized zones of transpression and transtension and areas where there is no surface expression suggesting the fault system is not yet mature. Although aseismic slip is common on subduction interfaces and mature strike-slip faults, this is the first study to document aseismic slip on a continental tectonic sliver boundary fault.

Complications and Long-Term Outcomes of Open Reduction and Plate Fixation of Proximal Humeral Fractures.

The optimal treatment of complex proximal humeral fractures in adults remains controversial. We evaluated the risk of complications and the long-term outcomes in patients with a severely displaced fracture or a fracture-dislocation of the proximal part of the humerus treated with open reduction and plate fixation (ORIF). Between 1995 and 2012, 5,897 consecutive patients with a proximal humeral fracture were referred to a specialist shoulder clinic for surgical assessment. Indications for surgery included anterior or posterior fracture-dislocation, substantial tuberosity involvement with >1 cm of displacement in a Neer 3 or 4-part fracture configuration, disengagement of the head from the shaft, or severe varus or valgus deformity of the head. All patients who met the surgical criteria and had been followed for 2 years were included, and standardized clinical and radiographic assessments of outcomes were performed. At a median of 10.8 years (range, 5 to 22 years) after ORIF, all surviving cognitively intact patients completed a patient-reported questionnaire assessing functional outcomes and satisfaction. Three hundred and sixty-eight patients (6.2%) met the inclusion criteria and had the appropriate follow-up. The study population had a high rate of complex fracture configurations; 77.2% had tuberosity involvement, 54.1% had complete head-shaft disengagement, and 44.0% had a dislocated head. Eighty-seven patients (23.6%) had postoperative stiffness, 25 (6.8%) had fixation failure/nonunion, and 16 (4.3%) had late osteonecrosis/posttraumatic osteoarthritis; these complications were the reason for the majority of the reoperations in the cohort. The survivorship until any reoperation was 74% at 10 years, but when reoperations for stiffness were excluded, the survivorship was 90% during the same time period. The patients' mean levels of pain, function, and satisfaction with treatment were good to excellent. Our results support the use of primary ORIF in medically fit patients with a severely displaced fracture or a fracture-dislocation of the proximal part of the humerus in centers where the expertise to carry out such treatment exists. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Results of modified JESS augmentation for fracture proximal humerus stabilized with percutaneous K-wires

Background: Proximal Humeral fractures are defined as fractures occurring at or proximal to surgical neck of Humerus1. Various methods are used for treating such conditions with mixed results. Closed reduction & percutaneous pinning with JESS augmentation with interconnecting double frames have been described for such fractures with satisfactory results. We aim to modify the same by mounting the JESS in a single frame with biplanar configuration review our results. Material and Methods: Total 15 patients with proximal humeral fractures were treated from 2016 to 2017 by fixation with JESS & K-wires. There were 10 (62.5%) males and 5 (37.5%) females, with a mean age of 57.5 years. Road traffic accident (RTA) was the most common mode of injury in patients less than 60 years old (4 out of 7), while fall on the ground was the most common cause in fractures in elderly patients (age>60 years, i.e. 6 out of 8). Displaced (more than 45° of angulation or >1cm of displacement) 2 and 3 part fractures and patients of age >20 years were included in the study. The fixator was removed when there was clinical (subsidence of pain) and radiological signs of union (bridging callus in 3 out of 4 cortices). Shoulder function was assessed using Constant scoring system. Result: 100 % union seen with duration ranging from 6weeks to 8 weeks followed by JESS removal. According to Constant score 3 cases (20%) showed excellent result, 9 cases (60%) showed good result, 2 cases (13.3%) showed fair result & 1 case(6.7%) showed poor result which may be due to noncompliance in physiotherapy & early pin loosening. Conclusion: External fixation with JESS & K-wires is an alternative cost effective option to treat Neer’s 2 & 3 part fractures, enables early mobilization & achieves safe healing with less soft tissue dissection. Keywords: Proximal humerus fractures, External fixator, JESS.

Quantifying Anatomic Deformations During Laryngoscopy.

For a variety of head and neck cancers, specifically those of the oropharynx, larynx, and hypopharynx, minimally invasive trans-oral approaches have been developed to reduce perioperative and long-term morbidity. However, in trans-oral surgical approaches anatomical deformation due to instrumentation, specifically placement of laryngoscopes and retractors, present a significant challenge for surgeons relying on preoperative imaging to resect tumors to negative margins. Quantifying the deformation due to instrumentation is needed in order to develop predictive models of operative deformation. In order to study this deformation, we used a CT/MR-compatible laryngoscopy system in concert with intraoperative CT imaging. 3D models of preoperative and intraoperative anatomy were generated. Mandible and hyoid displacements as well as tongue deformations were quantified for eight patients undergoing diagnostic laryngoscopy. Across patients, we found on average 1.3cm of displacement for these anatomic structures due to laryngoscope insertion. On average, the maximum displacement for certain tongue regions exceeded 4cm. The anatomical deformations quantified here can serve as a reference for describing how the upper aerodigestive tract anatomy changes during instrumentation and may be helpful in developing predictive models of intraoperative upper aerodigestive tract deformation.

How Displaced Are “Nondisplaced” Fractures of the Medial Humeral Epicondyle in Children? Results of a Three-Dimensional Computed Tomography Analysis

The management of fractures of the medial humeral epicondyle is controversial, but the primary issue is the relationship of outcomes to the extent of fracture displacement. This study compares the use of radiographs and three-dimensional computed tomography for determining the amount of displacement in medial humeral epicondylar injuries deemed to be minimally displaced (<5 mm) or nondisplaced. A retrospective review was performed on the cases of all patients with a fracture of the medial humeral epicondyle that had been diagnosed as minimally displaced or nondisplaced who were seen over a one-year period at our institution. Measurements of medial and anterior displacement on both the radiographs and three-dimensional computed tomography scan were recorded. Measurements of displacement were also recorded on internal oblique radiographs of the elbow, if available. Demographics, treatment, and any additional findings by computed tomography scans were noted. Means and Student t tests were utilized for statistical analysis. The eleven patients who met the inclusion criteria had a mean age of 12.2 years (range, 7.3 to 15.4 years). One fracture that involved the medial condyle on the computed tomography scan was excluded from the analysis. Anterior displacement was immeasurable on all but one lateral radiograph and recorded as 0 mm; the mean was 0.9 mm, which was significantly less than the anterior displacement on the three-dimensional computed tomography scan (mean, 8.8 mm; range, 0 to 15 mm) (p ≤ 0.001). Conversely, mean medial displacement on anteroposterior radiographs was 3.5 mm (range, 0 to 8 mm), which was significantly more than that measured on three-dimensional computed tomography scans (mean, 0.3 mm; range, 0 to 1.9 mm) (p ≤ 0.001). Mean displacement on internal oblique radiographs of the elbow was 6.6 mm (range, 0 to 10.5 mm) and matched the anterior displacement measurement on the three-dimensional computed tomography scan in three of the six patients (p = 0.037). Five of the six fractures with >1 cm of displacement by three-dimensional computed tomography scan underwent surgical treatment. Standard radiographs (anteroposterior and lateral views) are not sufficient to measure anterior displacement nor accurate enough to measure medial displacement of medial humeral epicondylar fractures. Internal oblique radiographs of the elbow appear to approximate the true anterior displacement, but three-dimensional computed tomography is the most accurate method to assess true displacement. The results of this study demonstrate that fractures that are found to be minimally displaced or nondisplaced by radiographs may have >1 cm of anterior displacement, for which surgery is usually recommended.

Root‐soil mechanical interactions during pullout and failure of root bundles

Roots play a major role in reinforcing and stabilizing steep hillslopes. Most studies in slope stability implement root reinforcement as an apparent cohesion by upscaling the behavior of static individual roots. Recent studies, however, have shown that much better predictions of slope stability can be made if the progressive failure of bundles of roots are considered. The characteristics of progressive failure depend on interactions between soil deformation and root bundle geometric and mechanical properties. We present a detailed model for the quantitative description of the mechanical behavior of a bundle of roots under strain‐controlled mechanical forcing. The Root Bundle Model explicitly considers typical values of root‐size spatial distribution (number and dimension of roots), geometric factors (diameter‐length proportion, tortuosity, and branching characteristics), and mechanical characteristics (tensile strength and Young's modulus) and interactions under various soil conditions (soil type, confining pressure, and soil moisture). We provide systematic analyses of the roles of these factors on the mechanical response of the bundle and explore the relative importance of various parameters to the macroscopic root‐soil mechanical response. We distinguish between increased strength imparted by small roots at small deformations and the resilience imparted by larger roots to the growth of large tensile cracks, showing that the maximal reinforcement of fine roots is reached within the first 5 cm of displacement whereas a root of 20 mm diameter may reach its maximal pullout force after 10 cm displacement. The model reproduces the gradual straining and ultimate residual failure behavior of root systems often observed in hillslopes, with progressive growth of tension cracks improving estimations of root reinforcement when considering the effects of root distribution and the variation of the pullout force as a function of displacement. These results enhance understanding of root reinforcement mechanisms and enable more realistic implementation of root reinforcement modeling for stability calculations of vegetated slopes and for guiding ongoing experimental efforts to gather critical root‐soil mechanical information.

Locked Plates Reduce Displacement of Vertically Unstable Pelvic Fractures in a Mechanical Testing Model

The purpose of this study is to compare a locked screw construct to a single iliosacral screw for fixation of a vertically unstable pelvic ring injury in a transforaminal sacral fracture model. Orthopaedic Trauma Association type 61-C1.3a2c5 fractures were created in 10 fresh frozen cadaveric pelvis specimens. Specimens were divided into two groups of five. In both groups, the anterior ring was stabilized with a six-hole 3.5-mm reconstruction plate. In the locked plate (LP) group, the posterior injury was stabilized using a two-hole locking plate with one solid 5.0-mm locking iliosacral screw directed onto the S1 body and a second locking screw directed into the lateral sacral ala. In the iliosacral screw group, the posterior injury was stabilized using a single cannulated 7.3-mm screw. Testing was conducted on a Materials Testing System. Values for displacement and rotation were recorded. Each pelvis was axially loaded with a compressive sine wave from 175 N to 350 N for 10,000 cycles to simulate limited weight bearing, with data recorded at 1,000 cycle increments. Two specimens in the iliosacral screw group displaced more than 1 cm during the first 1,000 cycles. These two specimens displayed gross fracture motion in all planes. All five specimens in the LP group completed 10,000 cycles of testing with less than 1 cm of displacement. A vector displacement calculation from the plane displacement data revealed that the LP group had significantly less displacement (median 1.9 mm) than the specimens in the iliosacral group (median 6.7 mm; p = 0.008) after 10,000 cycles. A two-hole plate locked head screw construct resulted in less displacement than a single iliosacral screw in a transforaminal sacral fracture model.

Desempenho de idosos em uma tarefa motora de demanda dupla de controle

A literatura sobre o processo de envelhecimento tem sistematicamente demonstrado a diferença de desempenho entre populações jovens e idosas. Em geral, os delineamentos de pesquisa envolvem indivíduos de 60 e até mesmo de 90 anos de idade, enquanto o grupo de jovens é representado por indivíduos em torno de 20 anos de idade. Esse procedimento pode ocultar mudanças de desenvolvimento que talvez influencie a interpretação dos resultados. Assim, o objetivo desse estudo foi examinar o efeito da idade cronológica no desempenho de uma habilidade motora. Foi utilizado um aparelho que possibilitou a execução de uma tarefa de posicionamento linear combinada ao controle de força. Os participantes receberam conhecimento de resultados verbal após a execução de 10 tentativas sobre o objetivo de atingir 20% da força máxima e o deslocamento de 35 cm. O desempenho foi medido pelo erro absoluto. A amostra contou com 150 participantes de 60 a 86 anos de idade, que realizaram as tentativas com a mão não-dominante e vendados. Os participantes foram divididos em três grupos etários (60, 70, 80 anos) e o desempenho também foi comparado a um grupo jovem (21 a 30 anos de idade). Houve correlação baixa, mas significante entre idade e controle de distância. Não houve diferença significante entre os grupos (exceto G20 e G80). Apesar da observação empírica dos instrutores sobre a diferença no desempenho motor de idosos de diferentes faixas etárias, o presente estudo não mostrou tais diferenças no desempenho dessa tarefa em particular. Talvez, considerando que os participantes eram fisicamente ativos, possíveis diferenças de desempenho relativas ao processo de envelhecimento, possam ter sido sobrepostas pelo estilo de vida ativo.

Surgery for scapula process fractures

Background Generally, scapula process fractures (coracoid and acromion) have been treated nonoperatively with favorable outcome, with the exception of widely displaced fractures. Very little has been published, however, regarding the operative management of such fractures and the literature that is available involves very few patients. Our hypothesis was that operative treatment of displaced acromion and coracoid fractures is a safe and effective treatment that yields favorable surgical results.Methods We reviewed 26 consecutive patients (27 fractures) treated between 1998 and 2007. Operative indications for these process fractures included either a painful nonunion, a concomitant ipsilateral operative scapula fracture, ≥ 1 cm of displacement on X-ray, or a multiple disruption of the superior shoulder suspensory complex. All patients were followed until they were asymptomatic, displayed radiographic fracture union, and had recovered full motion with no pain.Patients and results 21 males and 5 females, mean age 36 (18–67) years, were included in the study. 18 patients had more than one indication for surgery. Of the 27 fractures, there were 13 acromion fractures and 14 coracoid fractures. 1 patient was treated for both a coracoid and an acromion fracture. Fracture patterns for the acromion included 6 acromion base fractures and 7 fractures distal to the base. Coracoid fracture patterns included 11 coracoid base fractures and 3 fractures distal to the base. Mean follow-up was 11 (2–42) months. All fractures united and all patients had recovered full motion with no pain at the time of final follow-up. 3 patients underwent removal of hardware due to irritation from hardware components that were too prominent. There were no other complications.Interpretation While most acromion and coracoid fractures can be treated nonoperatively with satisfactory results, operative management may be indicated for displaced fractures and double lesions of the superior shoulder suspensory complex.

Inflation detected at Mount Veniaminof, Alaska, with campaign GPS

[1] In 2005 a repeat GPS campaign was conducted at 12 sites on Mt.Veniaminof Volcano and the surrounding region. A previous survey in 2002 provided initial locations for the sites. The deformation that occurred in the three years between the two surveys consist of ∼2–4 cm of displacement caused by the northwest convergence of the Pacific and North America Plates and ∼0.5–1 cm displacements caused by a deep intrusion that may be associated with eruptive activity in 2003–2005. The site velocities are corrected for compression using a pre-existing model for a locked subduction zone and the residuals modeled with volcanic sources in homogeneous and layered material. Although the data are fit equally well by several source models, we nevertheless gain important information about the deformation source. The best fitting models have depths that range from 3 to 17 km.

Minimally angulated pediatric wrist fractures: Is immobilization without manipulation enough?

Emergency department (ED) manipulation of complete minimally angulated distal radius fractures in children may not be necessary, due to the excellent remodeling potential of these fractures. The primary objective of this study was to determine the proportion of minimally angulated distal radius fractures managed in the ED with plaster immobilization that subsequently required manipulation. Our secondary objective was to document, at follow-up, changes in angulation for each wrist fracture. This retrospective cohort study reviewed consecutive records of all children with bi-cortical minimally angulated (</=15 degrees of angulation in the sagittal plane and </=0.5 cm of displacement) distal metaphyseal radius fractures, alone or in combination with distal ulnar fracture. Details of treatment, radiographic findings, and clinical outcomes during the subsequent orthopedic follow up were recorded. Of 124 patients included in the analysis, none required manipulation after their ED visit. All but 14 (11.3%) fractures were angulated </=20 degrees within the follow-up period. Two (1.6%) fractures that were initially angulated </=15 degrees progressed to 30 degrees -35 degrees , but remodeled within 2 years to nearly perfect anatomic alignment. By 6 weeks post-injury, no patients had clinically apparent deformity and all had normal function. Minimally angulated fractures of the distal metaphyseal radius managed in plaster immobilization without reduction in the ED are unlikely to require future surgical intervention.

The deformation field of the August 2003 eruption at Piton de la Fournaise, Reunion Island, mapped by ASAR interferometry

Three independent ASAR interferograms spanning the August 2003 Piton de la Fournaise eruption, reveal a 3 by 3 km asymmetric pattern of range changes centred on the Dolomieu crater northern flank. It corresponds to 30 cm of displacement towards the satellite east of the eruptive fissures and 7 cm away from the satellite west of the fissures. Displacements are caused by dyke emplacement below fissures. We model the deformation using a 3D mixed boundary element method for elastic media. This consists of a dyke defined by six geometric parameters and an overpressure gradient. A neighbourhood algorithm was applied to explore this 7 dimensional parameter space. The best‐fit model is a 57° eastward dipping dyke with a base lying around 1520 m a.s.l. The model provides new evidence of the dyke intrusion – related seaward displacements of the volcano eastern flank.

NONPROSTHETIC MANAGEMENT OF PROXIMAL HUMERAL FRACTURES

Many proximal humeral fractures can be treated without the need for hemiarthroplasty. Treatment choice is affected by fracture location and pattern, as well as by patient factors including age, activity level, quality of bone, and ability to comply with a regimen of therapy. Successful diagnosis and treatment of proximal humeral fractures is dependent on good-quality radiographs, but in some cases, intraoperative assessment of the fracture pattern is required for a complete and accurate diagnosis of the fracture pattern and severity. A discussion of nonsurgical and surgical treatment options and techniques needed to achieve anatomic reduction and stable fixation is important.