Using archival X-ray data, we find that the catalog location of the X-ray binary Scutum X-1 (Sct X-1) is incorrect and that the correct location is that of the X-ray source AX J183528-0737, which is ...15' to the west. Our identification is made on the basis of the 112 s pulse period for this object detected in an XMM-Newton observation, as well as spatial coincidence between AX J183528-0737 and previous X-ray observations. Based on the XMM-Newton data and archival RXTE data, we confirm secular spin-down over 17 yr with period derivative P approximately 3.9 x 10 super(-9) s s super(-1), but do not detect a previously reported X-ray iron fluorescence line. We identify a bright ( unk = 6.55) red (J - unk = 5.51) optical and infrared counterpart to AX J183528-0737 from 2MASS, a number of mid-IR surveys, and deep optical observations, which we use to constrain the extinction to and distance of Sct X-1. From these data, as well as limited near-IR spectroscopy, we conclude that Sct X-1 is most likely a binary system composed of a late-type giant or supergiant and a neutron star.
Multidetector-row computed tomography (MDCT) has emerged as a tool for quantitative assessment of parenchymal destruction, air trapping (density metrics), and airway remodeling (metrics relating ...airway wall and lumen geometry) in chronic obstructive pulmonary disease (COPD) and asthma. Critical to the accuracy and interpretability of these MDCT-derived metrics is the assurance that the lungs are scanned during a breathhold at a standardized volume.
A computer monitored turbine-based flow meter system was developed to control patient breathholds and facilitate static imaging at fixed percentages of the vital capacity. Because of calibration challenges with gas density changes during multibreath xenon CT, an alternative system was required. The design incorporated dual rolling seal pistons. Both systems were tested in a laboratory environment and human subject trials.
The turbine-based system successfully controlled lung volumes in 32/37 subjects, having a linear relationship for CT measured air volume between repeated scans: for all scans, the mean and confidence interval of the differences (scan1-scan2) was -9 mL (-169, 151); for total lung capacity alone 6 mL (-164, 177); for functional residual capacity alone, -23 mL (-172, 126). The dual-piston system successfully controlled lung volume in 31/41 subjects. Study failures related largely to subject noncompliance with verbal instruction and gas leaks around the mouthpiece.
We demonstrate the successful use of a turbine-based system for static lung volume control and demonstrate its inadequacies for dynamic xenon CT studies. Implementation of a dual-rolling seal spirometer has been shown to adequately control lung volume for multibreath wash-in xenon CT studies. These systems coupled with proper patient coaching provide the tools for the use of CT to quantitate regional lung structure and function. The wash-in xenon CT method for assessing regional lung function, although not necessarily practical for routine clinical studies, provides for a dynamic protocol against which newly emerging single breath, dual-energy xenon CT measures can be validated.
Abstract
Objective
Child pedestrian injuries represent a global public health burden. To date, most research on psychosocial factors affecting children’s risk of pedestrian injury focused on ...cognitive aspects of children’s functioning in traffic. Recent evidence suggests, however, that emotional aspects such as temperament-based fear and anger/frustration, as well as executive function-based emotional decision making, may also affect children’s safety in traffic. This study examined the role of emotions on children’s pedestrian behavior. Three hypotheses were considered: (a) emotion-based temperament factors of fear and anger/frustration will predict children’s risky decisions and behaviors; (b) emotional decision making will predict risky pedestrian decisions and behaviors; and (c) children’s pedestrian decision making will mediate relations between emotion and risky pedestrian behavior. The role of gender was also considered.
Methods
In total, 140 6- to 7-year-old children (M = 6.7 years, SD = 0.39; 51% girls) participated. Parent-report subscales of Child Behavior Questionnaire measured temperamental fear and anger/frustration. The Hungry Donkey Task, a modified version of Iowa Gambling Task for children, measured children’s emotional decision making, and a mobile virtual reality pedestrian environment measured child pedestrian behavior.
Results
Greater anger/frustration, lesser fear, and more emotional decision making all predicted poorer pedestrian decision making. The mediational model demonstrated that pedestrian decision making, as assessed by delays entering safe traffic gaps, mediated the relation between emotion and risky pedestrian behavior. Analyses stratified by gender showed stronger mediation results for girls than for boys.
Conclusions
These results support the influence of emotions on child pedestrian behavior and reinforce the need to incorporate emotion regulation training into child pedestrian education programs.
Background: Retinal vein pulsation is often absent in glaucoma, but can be induced by applying a graded ophthalmodynamometric force (ODF) to the eye, which is elevated in glaucoma. Aim: To assess ...whether ODF has a predictive value in determining glaucoma progression. Methods: 75 patients with glaucoma and suspected glaucoma were examined prospectively in 1996, and then re-examined at a mean of 82 months later. All subjects had intraocular pressure, visual fields, stereo optic disc photography and ODF measured on their initial visit. When venous pulsation was spontaneous, the ODF was said to be 0 g. At re-examination, central corneal thickness and blood pressure were also measured. Initial and subsequent optic disc photographs were compared and graded into those that had increased excavation and those that had remained stable. The relationship between increased excavation (recorded as a binary response) and the measured variables was modelled using a multiple mixed effects logistic regression. Results: ODF at the initial visit was strongly predictive of increased excavation (p = 0.004, odds ratio 1.16/g, range 0–60 g), with greater predictive value in women than in men (p = 0.004). Visual field mean deviation was predictive of increased excavation (p = 0.044), as was optic nerve haemorrhage in association with older age (p = 0.038). Central corneal thickness was not significantly predictive of increased excavation (p = 0.074) after having adjusted for other variables. Conclusion: ODF measurement seems to be strongly predictive of the patient’s risk for increased optic disc excavation. This suggests that ODF measurement may have predictive value in assessing the likelihood of glaucoma progression.
Background
The success of THA largely depends on correct placement of the individual components. Traditionally, these have been placed freehand using anatomic landmarks, but studies have shown poor ...accuracy with this method.
Questions/purposes
Specifically, we asked (1) does using fluoroscopy lead to more accurate and greater likelihood of cup placement with the Lewinnek safe zone than does freehand cup placement; (2) is there a learning curve associated with the use of fluoroscopy for cup placement; (3) does the use of fluoroscopy increase operative time; and (4) is there a difference in leg length discrepancy between freehand and fluoroscopic techniques?
Methods
This series consisted of 109 consecutive patients undergoing primary THA, conversion of a previous hip surgery to THA, and revision THA during a 24-month period. No patients were excluded from analysis during this time. The first 52 patients had cups placed freehand, and then the next 57 patients had acetabular components placed using fluoroscopy; the analysis began with the first patient treated using fluoroscopy, to include our initial experience with the technique. The abduction, version, and limb length discrepancy were measured on 6-week postoperative pelvic radiographs obtained with the patient in the supine position. Operative time, sex, age, BMI, diagnosis, operative side, and femoral head size were recorded as possible confounders.
Results
Cups inserted freehand were placed in the ideal range of abduction (30°–45°) and anteversion (5°–25°) 44% of the time. With fluoroscopy, placement in the Lewinnek safe zone for both measures significantly increased to 65%. The odds of placing the cup in the Lewinnek safe zone for abduction and version were 2.3 times greater with the use of fluoroscopy (95% CI, 1.2–5.0; p = 0.03). Patients undergoing primary THAs (32 freehand, 35 C-arm) had cup placement in the safe zone for abduction and version 44% of the time freehand and 57% of the time with fluoroscopy, which failed to reach statistical significance. There was no difference in operative time, patient age, sex, operative side, diagnosis, limb length discrepancy, or femoral head size between the two groups.
Conclusions
The use of fluoroscopy to directly observe pelvic position and acetabular component placement increased the success of placement in the Lewinnek safe zone in this cohort of patients having complex and primary THAs. This is a simple, low-cost, and quick method for increasing successful acetabular component alignment. The study population included a large proportion of patients having complex THAs, and further validation of this technique in patients undergoing straightforward, primary THAs needs to be done to understand if similar gains in accuracy for component placement can be expected in that group.
Level of Evidence
Level III, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.
Direct Metal Laser Re-Melting is a variant of the Selective Laser Sintering process, a Rapid Prototyping (RP) technology. This tool-less manufacturing technology has the potential of producing ...complex, high quality components from single-phase metal powders in short time scales. This is made possible by the production of consecutive two-dimensional layers. Unfortunately, finished components manufactured by this technique have their integrity and material properties dictated by the porosity within the laser re-melted structure. In order to maintain structural integrity comparable to conventionally produced components, metal components produced by the rapid prototyping method should exhibit a porosity of the order of maximum of ∼2% with corresponding bulk material properties. To achieve these objectives, process and laser parameters require optimisation for maximum densities to be attained. This paper reports on the development of a scanning strategy that produces stainless steel (316L) laser re-melted components which exhibit porosities of <1%, while maintaining the concept of rapid prototyping.
Background:
It is unknown whether race- or insurance-based disparities in health care exist regarding baseline knee pain, knee function, complete meniscal tear, or articular cartilage damage in ...patients who undergo anterior cruciate ligament reconstruction (ACLR).
Hypothesis:
Black patients and patients with Medicaid evaluated for ACLR would have worse baseline knee pain, worse knee function, and greater odds of having a complete meniscal tear.
Study Design:
Cross-sectional study; Level of evidence, 3.
Methods:
A cohort of patients (N = 1463; 81% White, 14% Black, 5% Other race; median age, 22 years) who underwent ACLR between February 2015 and December 2018 was selected from an institutional database. Patients who underwent concomitant procedures and patients of undisclosed race or self-pay status were excluded. The associations of race with preoperative Knee injury and Osteoarthritis Outcome Score (KOOS) Pain subscale, KOOS Function subscale, and intraoperatively assessed complete meniscal tear (tear that extended through both the superior and the inferior meniscal surfaces) were determined via multivariate modeling with adjustment for age, sex, insurance status, years of education, smoking status, body mass index (BMI), meniscal tear location, and Veterans RAND 12-Item Health Survey Mental Component Score (VR-12 MCS).
Results:
The 3 factors most strongly associated with worse KOOS Pain and KOOS Function were lower VR-12 MCS score, increased BMI, and increased age. Except for age, the other two factors had an unequal distribution between Black and White patients. Univariate analysis demonstrated equal baseline median KOOS Pain scores (Black, 72.2; White, 72.2) and KOOS Function scores (Black, 68.2; White, 68.2). After adjusting for confounding variables, there was no significant difference between Black and White patients in KOOS Pain, KOOS Function, or complete meniscal tears. Insurance status was not a significant predictor of KOOS Pain, KOOS Function, or complete meniscal tear.
Conclusion:
There were clinically significant differences between Black and White patients evaluated for ACLR. After accounting for confounding factors, no difference was observed between Black and White patients in knee pain, knee function, or complete meniscal tear. Insurance was not a clinically significant predictor of knee pain, knee function, or complete meniscal tear.
Background:
Opioid use and public insurance have been correlated with worse outcomes in a number of orthopaedic surgeries. These factors have not been investigated with anterior cruciate ligament ...reconstruction (ACLR).
Purpose/Hypothesis:
To evaluate if narcotic use, physical therapy location, and insurance type are predictors of patient-reported outcomes after ACLR. It was hypothesized that at 1 year postsurgically, increased postoperative narcotic use would be associated with worse outcomes, physical therapy obtained within the authors’ integrated health care system would lead to better outcomes, and public insurance would lead to worse outcomes and athletic activity.
Study Design:
Cohort study; Level of evidence, 2.
Methods:
All patients undergoing unilateral, primary ACLR between January 2015 and February 2016 at a large health system were enrolled in a standard-of-care prospective cohort. Knee injury and Osteoarthritis Score (KOOS) and the Hospital for Special Surgery Pediatric–Functional Activity Brief Scale (HSS Pedi-FABS) were collected before surgery and at 1 year postoperatively. Concomitant knee pathology was assessed arthroscopically and electronically captured. Patient records were analyzed to determine physical therapy location, insurance status, and narcotic use. Multivariable regression analyses were used to identify significant predictors of the KOOS and HSS Pedi-FABS score.
Results:
A total of 258 patients were included in the analysis (mean age, 25.8; 51.2% women). In multivariable regression analysis, narcotic use, physical therapy location, and insurance type were not independent predictors of any KOOS subscales. Public insurance was associated with a lower HSS Pedi-FABS score (–4.551, P = .047) in multivariable analysis. Narcotic use or physical therapy location was not associated with the HSS Pedi-FABS score.
Conclusion:
Increased narcotic use surrounding surgery, physical therapy location within the authors’ health care system, and public versus private insurance were not associated with disease-specific KOOS subscale scores. Patients with public insurance had worse HSS Pedi-FABS activity scores compared with patients with private insurance, but neither narcotic use nor physical therapy location was associated with activity scores. Physical therapy location did not influence outcomes, suggesting that patients be given a choice in the location they received physical therapy (as long as a standardized protocol is followed) to maximize compliance.
Background:
Patient-reported outcome measures are commonly used to measure knee pain and functional impairment. When structural abnormality is identified on examination and imaging, arthroscopic ...partial meniscectomy and chondroplasty are commonly indicated for treatment in the setting of pain and decreased function.
Purpose:
To evaluate the relationship between patient characteristics, mental health, intraoperative findings, and patient-reported outcome measures at the time of knee arthroscopy.
Study Design:
Cross-sectional study; Level of evidence, 3.
Methods:
Between February 2015 and October 2016, patients aged 40 years and older who were undergoing routine knee arthroscopy for meniscal and cartilage abnormality, without reconstructive or restorative procedures, were prospectively enrolled in this study. Routine demographic information was collected, and the Knee injury and Osteoarthritis Outcome Score (KOOS) Pain, Quality of Life (QoL), and Physical Function Short Form (PS) subscales and the mental and physical component subscales of the Veterans RAND 12-Item Health Survey (VR-12 MCS and VR-12 PCS) were administered preoperatively on the day of surgery. Intraoperative findings were collected in a standardized format. Patient demographics, intraoperative findings, and the VR-12 MCS were used as predictor values, and a multivariate analysis was conducted to assess for relationships with the KOOS and VR-12 as dependent variables.
Results:
Of 661 eligible patients, baseline patient-reported outcomes and surgical data were used for 638 patients (97%). Lower scores on both subscales of the VR-12 were predicted by female sex, positive smoking history, fewer years of education, and higher body mass index (BMI). All KOOS subscales were negatively affected by lower VR-12 MCS scores, female sex, lower education level, and higher BMI in a statistically meaningful way. Positive smoking history was associated with worse scores on the KOOS-PS. Abnormal synovial status was associated with worse KOOS-Pain.
Conclusion:
The demographic factors of sex, smoking status, BMI, and education level had an overwhelming impact on preoperative KOOS and VR-12 scores. Of interest, mental health as assessed by the VR-12 MCS was also a consistent predictor of KOOS scores. The only intraoperative finding with a significant association was abnormal synovial status and its effect on KOOS-Pain scores.
Background:
Injuries to the posterolateral corner (PLC) may occur concurrently with anterior cruciate ligament (ACL) injury.
Purpose/Hypothesis:
This study evaluated the outcomes of patients who ...underwent operative management of PLC injuries concurrently with ACL reconstruction in a prospective multicenter cohort. We hypothesized that there would be no differences in outcomes between patients who were treated with PLC repair and PLC reconstruction.
Study Design:
Cohort study; Level of evidence, 3.
Methods:
Patients undergoing ACL reconstruction were enrolled into a prospective longitudinal multicenter cohort between 2002 and 2008. Those with complete 6-year follow-up data (patient-reported outcomes and subsequent surgery information) were identified. Excluded from the study were patients with posterior cruciate ligament injuries. Patients who underwent PLC repair were compared with those who underwent PLC reconstruction with regard to interval from injury to surgery, need for revision surgery, and long-term outcomes at 6 years.
Results:
During the identified time frame, 3026 identified patients underwent primary ACL reconstruction; 34 (1.1%) also underwent concurrent PLC surgery (15 repairs, 19 reconstructions 18 allografts, 1 autograft). With the numbers available, we did not detect significant differences between groups regarding the rate of meniscal or chondral injuries. Median time to PLC reconstruction was 121 days as compared with 19 days for concurrent ACL reconstruction and PLC repair (P = .01). There were no between-group differences in Marx activity scores prior to surgery (P = .4). At 6-year follow-up, there were no between-group differences in Knee injury and Osteoarthritis Outcome Score (P = .36-.83) or International Knee Documentation Committee score (P = .84); however, patients treated with PLC reconstructions had lower Marx activity scores (4.1 vs 9.4; P = .02). There was 1 ACL revision in the PLC reconstruction group, and 1 of the PLC repairs was revised to a reconstruction during the follow-up period.
Conclusion:
Good outcomes were achieved at 6-year follow-up with both repair and reconstruction of PLC injuries treated concurrently with ACL reconstruction. The PLC reconstruction group had lower activity levels 6 years after surgery. The present data suggest that, for appropriately selected patients undergoing acute surgical treatment of combined ACL and PLC injuries, PCL repair can achieve good long-term outcomes.
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