Calibration lamp design, characterization, and implementation for the Michelson Interferometer for Global High-Resolution Thermospheric Imaging instrument on the Ionospheric Connection satellite.

We describe the design and ground-based performance of the two-color calibration lamp for the Michelson Interferometer for Global High-Resolution Thermospheric Imaging (MIGHTI) instrument on the NASA Ionospheric Connection (ICON) satellite. The calibration lamp assembly contains radio frequency excited krypton and neon lamps, which generate emission lines at 557 and 630 nm, respectively, and which are used to monitor thermal drifts in the two MIGHTI Doppler asymmetric spatial heterodyne interferometers. The lamps are coupled to two mixed optical fiber bundles that deliver the calibration signals to the two MIGHTI optical units. The assembly starts reliably, consumes <8 W, and has passed environmental testing for the ICON satellite. The total mass of the lamp assembly is 1.8 kg. Special features of the assembly and its implementation are described along with results of life tests.

High-efficiency echelle gratings for MIGHTI, the spatial heterodyne interferometers for the ICON mission.

Development of a new generation of low-groove density-blazed echelle gratings optimized for MIGHTI, a space-borne spatial heterodyne interferometer operating in the visible and near infrared is described. Special demands are placed on the wavefront accuracy, groove profile, and efficiency of these gratings. These demands required a new ruling for this application, with significant improvements over existing gratings. Properties of a new generation of highly efficient, plane gratings with 64 grooves/mm blazed at 8.2° are reported.

Spatial heterodyne spectroscopy at the Naval Research Laboratory.

Spatial heterodyne spectroscopy (SHS) is based on traditional Michelson interferometry. However, instead of employing retro-reflectors in the interferometer arms, one or both of which are moving, it uses fixed, tilted diffraction gratings and an imaging detector to spatially sample the optical path differences. This concept allows high-resolution, high-throughput spectroscopy without moving interferometer parts, particularly suitable for problems that require compact, robust instrumentation. Here, we briefly review about 20 years of ground- and space-based SHS work performed at the U.S. Naval Research Laboratory (NRL), which started with a visit by Prof. Fred Roesler to NRL in 1993.

Open ankle fractures: who gets them and why?

Open ankle fractures present a significant clinical challenge. The management and outcome of these injuries has been extensively reported, but there have been no reports of the epidemiology and how this has changed over time. We report 178 adult patients with open ankle fractures presenting to our unit over a twenty-three year period. The study centre is the only hospital receiving adult orthopaedic trauma in the region and has a defined population. The incidence of open ankle fractures was 1.5/10(5)/year, representing 1.5 % of all ankle fractures. The mean age was 55 years (range 16-96), with the highest incidence occurring in women over the age of 90. The most common mechanism was a simple fall with only 26 % of cases due to a motor vehicle collision (MVC). 82 % of cases were isolated injuries. Social deprivation had no significant influence on the incidence, but there was a difference in the mechanism with the majority of injuries in the most deprived quintile caused by MVCs and significantly fewer due to simple falls (p = 0.047). Over the twenty-three years, there was a significant increase in the mean age from 44 to 64 years (p = 0.03). The overall incidence remained constant over the two decades. In common with many traumatic injuries, open ankle fractures are increasingly low-energy insufficiency fractures affecting elderly patients, particularly older women. This has implications for service planning and training as well as the surgical intervention in these patients.

Radial head replacement for acute complex fractures: what are the rate and risks factors for revision or removal?

BACKGROUND: When treating complex radial head fractures, important goals include prevention of elbow or forearm instability, with restoration of radiocapitellar contact essential. When open reduction and internal fixation cannot achieve this, radial head replacement is routinely employed, but the frequency of and risk factors for prosthesis revision or removal are not well defined. QUESTIONS/PURPOSES: We determined (1) the frequency of prosthesis revision or removal after radial head replacement for acute complex unstable radial head fractures, (2) risk factors for revision or removal, and (3) functional outcomes after radial head replacement. METHODS: We identified from our prospective trauma database all patients over a 16-year period managed acutely for unstable complex radial head fractures with primary radial head replacement. Of the 119 patients identified, 105 (88%) met our inclusion criteria; mean age was 50 years (range, 16-93 years) and 57 (54%) were female. All implants were uncemented monopolar prostheses, of which 86% were metallic and 14% silastic. We recorded further procedures for prosthesis revision or removal for any cause, with a minimum followup of 1 year (n = 105). Cox regression analysis was used to determine independent factors associated with revision or removal when controlling for baseline patient (age, sex, comorbidities) and fracture (location, classification, associated injury) characteristics. Short-term functional outcomes (Broberg and Morrey score, ROM) were determined from retrospective review of clinic followup (n = 74), with a minimum followup of 3 months. RESULTS: Twenty-nine patients (28%) underwent prosthesis revision (n = 3) or removal (n = 26) at a mean of 6.7 years (range, 1.8-18 years) after injury. Independent risk factors for removal or revision were silastic implant type and lower age. At a mean of 1.1 years (range, 0.3-5.5 years) after surgery, mean Broberg and Morrey score was 80 out of 100 (range, 40-99). Mean elbow flexion was 133° (range, 90°-159°; SD, 13°), extension 21° (range, 0°-80°; SD, 17°), flexion arc 112° (range, 10°-140°; SD, 25°), pronation 84° (range, 0°-90°; SD, 18°), supination 73° (range, 0°-90°; SD, 28°), and forearm rotation arc 156° (range, 0°-180°; SD, 38°). CONCLUSIONS: We demonstrated a high removal or revision rate after radial head replacement for acute unstable complex fractures, with lower age and silastic implants independent risk factors. Younger patients should be counseled regarding the increased risk of requiring further surgery after radial head replacement. Future work should focus on long-term patient-reported outcomes after these injuries. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

Changing epidemiology of adult fractures in Scotland.

BACKGROUND: Fracture epidemiology in adults is changing but there is very little information about the rate of change or whether the change affects males and females equally. METHODS: We have compared fracture incidence in two similar populations 50-60 years apart. A study of fractures in Dundee, Scotland and Oxford, England, in 1954-1958, was compared with a similar cohort of fractures in Edinburgh, Scotland, in 2010-2011. Fracture incidence in patients >35 years was recorded in both time periods. RESULTS: The incidence of fractures increased by 50% between the two time periods, although the increase in males was only 5% compared with 85% in females. The spectrum of fractures has changed considerably, and there has been an increase in the incidence of both fragility and non-fragility fractures. Analysis showed an increased incidence of fall-related fractures in all age groups in both males and females. INTERPRETATION: There has been a substantial change in the incidence of fractures in the last 50-60 years. These have been caused by greater longevity and by considerable social and economic changes.

Elderly pelvic fractures: the incidence is increasing and patient demographics can be used to predict the outcome.

OBJECTIVES: To (1) to determine the incidence of elderly pelvic fractures over the last decade, (2) describe the epidemiology and outcome of patients with pubic rami fractures and compare these to those patients sustaining all other pelvic fractures, and (3) identify independent predictors of length of stay, return to domicile, and 1-year mortality for patients with pubic rami fractures. METHODS: We retrospectively identified 937 elderly patients (≥65 years) with pelvic fractures presenting to the study centre over a 15-year period. Patient demographics, mechanism of injury, and associated fractures were recorded for a defined 2-year period. Outcomes assessed were length of stay, return to original place of domicile, and 1-year mortality. RESULTS: The incidence increased from 7.9 per 100,000 to 13.1 per 100,000. The majority were fragility fractures of the pubic rami (84%). Patients sustaining a pubic rami fracture were older, more likely to be female, less deprived and have sustained an isolated injury by a low-energy mechanism. Patients sustaining a pubic rami fracture were less likely to return to their original place of domicile. Pre-injury independence and mobility, socioeconomic status, associated fractures, energy of injury, and male gender were independent predictors of length of stay, return to original place of domicile, and 1-year mortality. CONCLUSION: The incidence of elderly pelvic fractures is increasing, and fractures of the pubic ramus have different patient demographics compared to other pelvic fractures. Patient demographics could be used to predict: length of stay, return to domicile, and 1-year mortality after a pubic rami fracture. LEVEL OF EVIDENCE: Retrospective prognostic study, Level IV.

Michelson Interferometer for Global High-Resolution Thermospheric Imaging (MIGHTI) On-Orbit Wind Observations: Data Analysis and Instrument Performance.

The design, principles of operation, calibration, and data analysis approaches of the Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) on the NASA Ionospheric Connection (ICON) satellite have been documented prior to the ICON launch. Here we update and expand on the MIGHTI wind data analysis and discuss the on-orbit instrument performance. In particular, we show typical raw data and we describe key processing steps, including the correction of a "signal-intensity dependent phase shift," which is necessitated by unexpected detector behavior. We describe a new zero-wind calibration approach that is preferred over the originally planned approach due to its higher precision. Similar to the original approach, the new approach is independent of any a priori data. A detailed update on the wind uncertainties is provided and compared to the mission requirements, showing that MIGHTI has met the ICON mission requirements. While MIGHTI observations are not required to produce absolute airglow brightness profiles, we describe a relative brightness profile product, which is included in the published data. We briefly review the spatial resolution of the MIGHTI wind data in addition to the data coverage and data gaps that occurred during the nominal mission. Finally, we include comparisons of the MIGHTI wind data with ground-based Fabry-Perot interferometer observations and meteor radar observations, updating previous studies with more recent data, again showing good agreement. The data processing steps covered in this work and all the derived wind data correspond to the MIGHTI data release Version 5 (v05).

The epidemiology of radial head and neck fractures.

PURPOSE: The aim of this study was to define the epidemiological characteristics of proximal radial fractures. METHODS: Using a prospective trauma database of 6,872 patients, we identified all patients who sustained a fracture of the radial head or neck over a 1-year period. Age, sex, socioeconomic status, mechanism of injury, fracture classification, and associated injuries were recorded and analyzed. RESULTS: We identified 285 radial head (n = 199) and neck (n = 86) fractures, with a patient median age of 43 years (range, 13-94 y). The mean age of male patients was younger when compared to female patients for radial head and neck fractures, with no gender predominance seen. Gender did influence the mechanism of injury, with female patients commonly sustaining their fracture following a low-energy fall. Radial head fractures were associated more commonly with complex injuries according to the Mason classification, while associated injuries were related to age, the mechanism of injury, and increasing fracture complexity. CONCLUSIONS: Radial head and neck fractures have distinct epidemiological characteristics, and consideration for osteoporosis in a subset of patients is recommended. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic IV.

How useful are meta-analyses in orthopedic trauma?

BACKGROUND: Meta-analysis has become accepted as a methodically rigorous research tool, and as a result, many meta-analyses have been undertaken in orthopedic trauma, the implication being that their conclusions have improved surgeons' knowledge and facilitated improved clinical care. There have been criticisms of the methodology used in a number of meta-analyses; however, there has been no previous study of the clinical usefulness of their conclusions. METHODS: A study of 60 orthopedic trauma meta-analyses published during or after 2000 was undertaken. We divided the conclusions of the meta-analyses into four types depending on their innovation and potential for improving clinical care. We also separated the meta-analyses according to whether they were undertaken by the Cochrane Collaboration or by independent surgeons. RESULTS: Only 4 (6.7%) of the meta-analyses contained new, clinically useful, information, and 22 (36.7%) had no conclusions at all. A further 25 (41.7%) contained conclusions that were already in the standard orthopedic trauma literature. Approximately 70% of the Cochrane Collaborations had no conclusions. CONCLUSIONS: We found considerable variability in the clinical usefulness of orthopedic trauma meta-analyses, and we question the clinical usefulness of this type of research.

Radial head and neck fractures: functional results and predictors of outcome.

BACKGROUND: The purpose of this study was to determine the functional outcomes and predictive factors of radial head and neck fractures. METHODS: Over an 18-month period, we performed a prospective study of 237 consecutive patients with a radiographically confirmed proximal radial fracture (156 radial head and 81 radial neck). Follow-up was carried out over a 1-year period using clinical and radiologic assessment, including the Mayo Elbow Score (MES). Multivariate regression analysis was used to determine significant predictors of outcome according to the MES. RESULTS: Of the 237 patients enrolled in the study, 201 (84.8%) attended for review, with a mean age of 44 years (range, 16-83 years; standard deviation, 17.3). One hundred eighty-seven (93%) patients achieved excellent or good MESs. The mean MES for Mason type-I (n = 103) and type-II (n = 82) fractures was excellent, with only two patients undergoing surgical intervention. For Mason type-III (n = 11) and type-IV (n = 5) fractures, the flexion arc, forearm rotation arc, and MES in the nonoperatively treated patients were not significantly different (all p ≥ 0.05) from those managed operatively. Regression analysis revealed that increasing age, increasing fracture complexity according to the AO-OTA classification, increasing radiographic comminution, and operative treatment choice were independently significant predictors of a poorer outcome (all p < 0.05). CONCLUSIONS: A majority of radial head and neck fractures can be treated nonoperatively, achieving excellent or good results. Age, fracture classification, radiographic comminution, and treatment choice are important factors that determine recovery.

Recreational mountain biking injuries.

Mountain biking is increasing in popularity worldwide. The injury patterns associated with elite level and competitive mountain biking are known. This study analysed the incidence, spectrum and risk factors for injuries sustained during recreational mountain biking. The injury rate was 1.54 injuries per 1000 biker exposures. Men were more commonly injured than women, with those aged 30-39 years at highest risk. The commonest types of injury were wounding, skeletal fracture and musculoskeletal soft tissue injury. Joint dislocations occurred more commonly in older mountain bikers. The limbs were more commonly injured than the axial skeleton. The highest hospital admission rates were observed with head, neck and torso injuries. Protective body armour, clip-in pedals and the use of a full-suspension bicycle may confer a protective effect.

Radial shortening following a fracture of the proximal radius.

BACKGROUND AND PURPOSE: The Essex-Lopresti lesion is thought to be rare, with a varying degree of disruption to forearm stability probable. We describe the range of radial shortening that occurs following a fracture of the proximal radius, as well as the short-term outcome in these patients. PATIENTS AND METHODS: Over an 18-month period, we prospectively assessed all patients with a radiographically confirmed proximal radial fracture. Patients noted to have ipsilateral wrist pain at initial presentation underwent bilateral radiography to determine whether there was disruption of the distal radio-ulnar joint suggestive of an Essex-Lopresti lesion. Outcome was assessed after a mean of 6 (1.5-12) months using clinical and radiographic results, including the Mayo elbow score (MES) and the short musculoskeletal function assessment (SMFA) questionnaire. One patient with a Mason type-I fracture was lost to follow-up after initial presentation. RESULTS: 60 patients had ipsilateral wrist pain at the initial assessment of 237 proximal radial fractures. Radial shortening of ≥ 2mm (range: 2-4mm) was seen in 22 patients (mean age 48 (19-79) years, 16 females). The most frequent mechanism of injury was a fall from standing height (10/22). 21 fractures were classified as being Mason type-I or type-II, all of which were managed nonoperatively. One Mason type-III fracture underwent acute radial head replacement. Functional outcome was assessed in 21 patients. We found an excellent or good MES in 18 of the 20 patients with a Mason type-I or type-II injury. INTERPRETATION: The incidence of the Essex-Lopresti lesion type is possibly under-reported as there is a spectrum of injuries, and subtle disruptions often go unidentified. A full assessment of all patients with a proximal radial fracture is required in order to identify these injuries, and the index of suspicion is raised as the complexity of the fracture increases.

Nonoperative fracture treatment in the modern era.

BACKGROUND: Nonoperative fracture treatment has been used for millennia, but there has been no demographic study of its use for half a century. In the last 50 to 60 years, there has been an increased interest in operative fracture fixation and in many specialized Trauma hospitals nonoperative management is less frequently used. However, these specialized hospitals do not reflect fracture treatment in the whole community, and we have undertaken a study to investigate the current prevalence of nonoperative fracture treatment. METHODS: A retrospective analysis of 7,863 consecutive fractures in a defined population was undertaken. The use of nonoperative management in different fractures was assessed as was the influence of fracture severity, mode of injury, multiple fractures and social deprivation in the choice of treatment. A comparison of current treatment with that of the 1940s and 1950s was undertaken. RESULTS: The prevalence of nonoperative treatment was 74.6% with 91.6% of children and 67.6% of adults being treated nonoperatively. There were significant differences in upper and lower limb fractures in both children and adults. The major determinant of nonoperative management was age, although the severity of fracture, mode of injury, and presence of multiple fractures were also important. Social deprivation was not a significant factor except in adult metacarpal fractures. CONCLUSIONS: Nonoperative treatment remains the most widely used method of fracture management. Its prevalence decreases with age, particularly in lower limb fractures. In children, there is a bimodal operative treatment distribution and an increasing prevalence of operative treatment. In some adult fractures, the prevalence of surgery is increasing, but in others, we operate no more frequently than in the 1950s, despite improved operative techniques.

Nonunions of the proximal humerus: their prevalence and functional outcome.

BACKGROUND: : We present an analysis of the prevalence of proximal humeral nonunions and an assessment of their functional outcome. METHODS: : The results of a study of 11 proximal humeral nonunions taken from a previous prospective study of 1,027 consecutive proximal humeral fractures were analyzed to determine the demography of the patient population, the Constant and Neer scores at 6 weeks, 13 weeks, 26 weeks, and 1 year and the functional outcome of the patients. All patients had been followed for 1 year and standard anteroposterior and modified axial X-rays taken at each assessment. The possible factors associated with proximal nonunion were studied. RESULTS: : The prevalence of proximal humeral nonunion is 1.1%, although it rises to about 8% if metaphyseal comminution is present and 10% if there is between 33% and 100% translation of the surgical neck. The effect of nonunion on function is considerable, even as early as 6 weeks after fracture. Our results show a deterioration of overall glenohumeral function after 6 months compared with patients whose fractures unite. Return to routine activities of daily living is markedly slower in the presence of a nonunion. The nonunions occurred in older patients but the age difference was not statistically significant. CONCLUSIONS: : Our results show that nonunion after nonoperative treatment of proximal humeral fractures is much less than has previously been reported and they suggest that age, metaphyseal comminution and fracture displacement are all factors in the development of nonunion. They also indicate that if operative treatment is required for proximal humeral nonunion it should not be delayed beyond 6 months after fracture and ideally should be performed as soon as the presence of a nonunion has become established this frequently being about 3 months after fracture.

The changing epidemiology of open fractures in vehicle occupants, pedestrians, motorcyclists and cyclists.

AIMS: To investigate the changing epidemiology of open fractures in vehicle occupants, pedestrians, motorcyclists and cyclists. MATERIALS AND METHODS: Data on all non-spinal open fractures admitted to the Royal Infirmary of Edinburgh after a road traffic accident between 1988 and 2010 were collected and analysed to provide information about the changing epidemiology in different patient groups. Demographic information was collected on all patients with the severity of injury being analysed with the Injury Severity Score (ISS), Musculoskeletal Index (MSI) and the number of open fractures. The severity of the open fractures was analysed using the Gustilo classification. The 23-year study period was divided into four shorter periods and the results were compared. RESULTS: There were 696 patients treated in 23 years. Analysis showed that the incidence of RTA open fractures initially fell in both males and females and continued to fall in females during the 23 years. In males it levelled off about 2000. The age of the female patients also fell during the study period but it did not change in males. The only patient group to show an increased incidence of open fractures were cyclists. In vehicle occupants the incidence fell throughout the study period but it levelled off in pedestrians and motorcyclists. There was no difference in the severity of injury in any group during the study period. The most severe open fractures were those of the distal femur and femoral diaphysis although open tibial diaphyseal fractures were the most common fracture in all patient groups. CONCLUSIONS: Improved car design and road safety legislation has resulted in a reduction in the incidence of open fractures in vehicle occupants, pedestrians and motorcyclists. The most obvious group to have benefitted from this are older female pedestrians. The only group to show an increase in age during the study period were male motorcyclists.

Fractures in older adults. A view of the future?

INTRODUCTION: It is accepted that the incidence of fractures in patients aged ≥ 65 years is increasing but little is known about which fractures are becoming more common in this group of patients. Virtually all research has concentrated on the classic fragility fractures of the proximal femur, proximal humerus, pelvis, spine and distal radius but it is likely that other fractures are becoming more common. METHODS: We have examined two prospectively collected databases 10 years apart to see which fractures are becoming more common in ≥ 65 year old patients. We compared the fractures to look for epidemiological differences over the 10-year period and we compared the epidemiology of the fractures that had increased in incidence with equivalent fractures in the < 65 year old population. RESULTS: Analysis shows that in older female patients fractures of the clavicle, finger phalanges, ankle and metatarsus are increasing in incidence. In males there is an increasing incidence of fractures of the proximal humerus, distal humerus, metacarpus, pelvis, femoral diaphysis, distal tibia and ankle. In females the basic epidemiology of fractures in the ≥ 65 year old population was very similar to the fractures seen in younger females and we believe that the increasing incidence of fractures in the future will mainly be low velocity fractures following falls. In older males however, it is apparent that there is a much wider variation in the causes of fracture. DISCUSSION: We believe that the changes in fracture epidemiology in older patients relate to improved health and longevity and analysis of our population during the study period shows significant social changes which are associated with increased longevity and improved health. It is probable that fractures in older patients will continue to increase in incidence and that other fractures that are now commonly seen in middle-aged patients will be seen in older patients. Surgeons will have to treat more complex fractures in older males than in older females and it is likely that there will be a higher incidence of open and multiple fractures. Appropriate management techniques will need to be established.

Retrieval of Lower Thermospheric Temperatures from O2 A Band Emission: The MIGHTI Experiment on ICON.

The Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) is a satellite experiment scheduled to launch on NASA's Ionospheric Connection Explorer (ICON) in 2017. MIGHTI is designed to measure horizontal neutral winds and neutral temperatures in the terrestrial thermosphere. Temperatures will be inferred by imaging the molecular oxygen Atmospheric band (A band) on the limb in the lower thermosphere. MIGHTI will measure the spectral shape of the A band using discrete wavelength channels to infer the ambient temperature from the rotational envelope of the band. Here we present simulated temperature retrievals based on the as-built characteristics of the instrument and the expected emission rate profile of the A band for typical daytime and nighttime conditions. We find that for a spherically symmetric atmosphere, the measurement precision is 1 K between 90-105 km during the daytime whereas during the nighttime it increases from 1 K at 90 km to 3 K at 105 km. We also find that the accuracy is 2 K to 11 K for the same altitudes. The expected MIGHTI temperature precision is within the measurement requirements for the ICON mission.

Tibial Fracture Nonunion and Time to Healing After Reamed Intramedullary Nailing: Risk Factors Based on a Single-Center Review of 1003 Patients.

OBJECTIVE: To determine factors associated with nonunion of adult tibial fractures. DESIGN: Retrospective review with data collection for logistic regression and survival analysis. SETTING: Scottish Level I trauma center, 1985-2007. PATIENTS: During this period, 1590 adult tibial fractures were treated by reamed nailing and 1003 fractures met all inclusion criteria for the chosen analysis. INTERVENTION: Reamed intramedullary nailing. MAIN OUTCOME MEASURES: Record of nonunion diagnosis and final union time with characteristics, including age, gender, closed or open injury, OTA/AO classification, Gustilo classification, fasciotomy, infection, polytrauma, smoking, and injury severity score. RESULTS: The overall nonunion rate was 12%, and median time to healing was 18 weeks. Age significantly influenced nonunion, with middle-aged patients at highest risk. Both fracture type (closed/open) and morphology (OTA/AO classification) significantly influenced nonunion risk and time to union. Among closed injuries, the highest nonunion rate was for OTA/AO type B fractures (15%). Among open injuries, the highest nonunion rate was for OTA/AO type C (61%). Both compartment syndrome and smoking did not significantly influence nonunion risk but did significantly extend time to union. CONCLUSIONS: Injury characteristics including fracture morphology and severity of soft tissue injury were strong predictors of compromised fracture healing. Age also influenced nonunion risk in an unexpected way, with highest rates in the middle decades of adulthood. Future studies should consider the possibility of similar age-related effects and clinical studies should seek to identify explanations for why this may arise, including both physiological and socio-behavioral factors. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.