In pursuit of blending polymers with carbon nanotubes

A liquid-solid phase separation method has been developed here to separate polymer/CNT blended phases with specific bundle size distribution from master heterogeneous polymer/CNT dispersions. This liquid-solid phase separation is triggered through addition of a non-solvent in the system. The fundamental issue of dispersing carbon nanotubes (CNTs) dispersion within a polymer matrix is also addressed in this work by studying a non-solvent induced liquid-solid phase separation process in polyacrylonitrile/CNT composite systems. To visualize the effect of phase separation, hybrid polymer/CNT buckypapers were formed through filtration. The hybrid film morphology is graded showing a distinct CNT-rich and polymer-rich layer. Examination of this layered structure reveals the separation of CNTs with specific bundle size. CNTs were uniformly dispersed within the polymer-rich layer due to a preferred polymer-CNT interaction during phase separation. Experimental, theoretical, and molecular dynamics studies were performed to show the fundamental mechanism behind layer formation in the composites and to understand the specificity of preferential polymer-CNT interactions. To this end, a geometric dependence described by a ‘cylinder-in-sphere’ model was established and shows a link between the critical CNT bundle size and polymer radius of gyration (Rg), which is dictates preferential polymer-CNT interactions. This model represents the geometric relationship required to form a blended polymer-CNT phase in the system under the phase separation conditions used. Understanding the use of phase separation as well as this geometrical dependence between filler and polymer is important to pinpoint nano-filler dispersion limits. Identifying these limits is critical toward the processing of superior polymer-based composites which fully utilizes the nano-filler reinforcement. Please click Additional Files below to see the full abstract

Ageism in Consent? In a decision-making capable geriatric orthopaedic trauma patient population, does increased age impact who physicians consent for surgical fixation?

Introduction: Persistent misconceptions of frailty and dementia in geriatric patients impact physician-patient communication and leave patients vulnerable to disempowerment. Our study examines the consenting process in an orthogeriatric trauma patient population to determine if there is a relationship between increased age at presentation and utilization of health care proxies (HCPs) for surgical procedure consent. Methods: We retrospectively reviewed medical records of patients aged 65 and older admitted for an operative fracture between 2013 and 2016. Patients were considered decision-making capable if there was absence of history of cognitive impairment prior to surgical consent and if the patients screened negative in a pre-surgical Confusion Assessment Method (CAM) and Mini-Cog Assessment. Data was analyzed via chi-squared and t-test analysis in SPSS. Results: 510 patients were included, and 276 (54.1%) patients were deemed capable of consent. 27 (9.8%) decision-making capable patients had HCPs consent for surgery. 20 of the 27 (74.1%) were 80 years of age or older and 7 patients between 70 and 79 had HCP consent. (p=0.07). HCP consent was significant for age (p\u3c0.001), income level (p=0.03), and HCP physically present at consult (p\u3c0.001). Additionally, language other than English was found to be a significant predictor of HCP consent (p=0.035). Conclusion: It is concerning that cognitively intact geriatric orthopaedic trauma patients are not always consented for their own surgical procedures. Factors including age, income, and language contribute to increased risk of HCP consent. Increased physician vigilance and adoption of institutional consenting guidelines can reinforce appropriate respect of geriatric patients’ consenting capacity

Results of a Feasibility Randomized Controlled Trial (RCT) of the Toolkit for Optimal Recovery (TOR): A Live Video Program to Prevent Chronic Pain in At-Risk Adults with Orthopedic Injuries

Background: Orthopedic injuries are the leading cause of hospital admissions in the USA, and many of these patients transition into chronic pain. Currently, there are no evidence-based interventions targeting prevention of chronic pain in patients with orthopedic injuries. We iteratively developed a four-session intervention “The Toolkit for Optimal Recovery” (TOR) which we plan to subsequently test for efficacy in a phase III hybrid efficacy-effectiveness multi-site clinical trial. In order to prevent methodological weaknesses in the subsequent trial, we conducted a feasibility pilot to evaluate the TOR delivered via secure live video versus usual care (UC) in patients with orthopedic injuries from an urban, level I trauma clinic, who screen in as at risk for chronic pain and disability. We tested the feasibility of recruitment, acceptability of screening, and randomization methods; acceptability of the intervention, treatment adherence, and treatment fidelity; satisfaction with the intervention; feasibility of the assessment process at all time points; acceptability of outcome measures for the definitive trial; and within-treatment effect sizes. Methods: We aimed to recruit 50–60 participants, randomize, and retain them for ~ 4 months. Assessments were done electronically via REDCap at baseline, post-intervention (approximately 5 weeks after baseline), and 3 months later. We followed procedures we intend to implement in the full-scale hybrid efficacy-effectiveness trial. Results: We recruited 54 participants and found that randomization and data collection procedures were generally acceptable. The majority of participants were white, educated, and employed. Warm hand-off referrals were more effective than research assistants directly approaching patients for participation without their providers’ engagement. Feasibility of recruitment, acceptability of screening, and randomization were good. Satisfaction with the program, adherence to treatment sessions, and treatment fidelity were all high. There were no technical issues associated with the live video delivery of the TOR. There was minimal missing data and outcome measures were deemed appropriate. Effect sizes for improvement after participation in TOR were moderate to large. There were many lessons learned for future trials. Conclusions: This study provided evidence of the feasibility of the planned hybrid efficacy-effectiveness trial design when implemented at our home institution. Establishing feasibility of the intervention and study procedures at other trauma centers with more diverse patient populations and different clinical practices is required before a multi-site phase III efficacy-effectiveness trial. Trial registration: ClinicalTrials.gov ID: NCT03405610. Registered on January 28, 2018—retrospectively registered

Blunt popliteal artery injury following tibiofemoral trauma: vessel-first and bone-first strategy

Purpose: Blunt popliteal artery injury (BPAI) is a potentially limb-threatening sequela of tibiofemoral (knee) dislocations and fractures. Associated amputation rates for all popliteal artery (PA) injuries range between 10 and 50%. It is unclear whether PA repair or bone stabilization should be performed first. We analyzed (long-term) clinical outcomes of BPAI patients that received initial PA repair (vessel-first, VF) versus initial external stabilization (bone-first, BF). Methods: Retrospectively, all surgically treated BPAI patients between January 2000 and January 2019, admitted to two level 1 trauma centers were included. Clinical outcomes were determined, stratified by initial management strategy (VF and BF). Treatment strategy was determined by surgeon preference, based on associated injuries and ischemia duration. Primary outcomes (amputation and mortality) and secondary outcomes (claudication and complications) were determined. Results: Of 27 included BPAI patients, 15 were treated according to the VF strategy (56%) and 12 according to the BF strategy (44%). Occlusion was the most frequently encountered BPAI in 18/27 patients (67%). Total delay and in-hospital delay were comparable between groups (p = 1.00 and p = 0.82). Revascularization was most frequently performed by PA bypass (59%). All patients had primary limb salvage during admission (100%). One secondary amputation due to knee pain was performed in the BF group (4%). During a median clinical follow-up period of 2.7 years, three PA re-interventions were performed, two in the BF group and one in the VF group. None suffered from (intermittent) claudication. Conclusion: Blunt popliteal artery injury (BPAI) is a rare surgical emergency. Long-term outcomes of early revascularization for BPAI appear to be good, independent of initial management strategy. The BF strategy may be preferred in case of severe orthopedic injury, if allowed by total ischemia duration

Does the SORG Orthopaedic Research Group Hip Fracture Delirium Algorithm Perform Well on an Independent Intercontinental Cohort of Patients With Hip Fractures Who Are 60 Years or Older?

Background Postoperative delirium in patients aged 60 years or older with hip fractures adversely affects clinical and functional outcomes. The economic cost of delirium is estimated to be as high as USD 25,000 per patient, with a total budgetary impact between USD 6.6 to USD 82.4 billion annually in the United States alone. Forty percent of delirium episodes are preventable, and accurate risk stratification can decrease the incidence and improve clinical outcomes in patients. A previously developed clinical prediction model (the SORG Orthopaedic Research Group hip fracture delirium machine-learning algorithm) is highly accurate on internal validation (in 28,207 patients with hip fractures aged 60 years or older in a US cohort) in identifying at-risk patients, and it can facilitate the best use of preventive interventions; however, it has not been tested in an independent population. For an algorithm to be useful in real life, it must be valid externally, meaning that it must perform well in a patient cohort different from the cohort used to "train" it. With many promising machine-learning prediction models and many promising delirium models, only few have also been externally validated, and even fewer are international validation studies. Question/purpose Does the SORG hip fracture delirium algorithm, initially trained on a database from the United States, perform well on external validation in patients aged 60 years or older in Australia and New Zealand? Methods We previously developed a model in 2021 for assessing risk of delirium in hip fracture patients using records of 28,207 patients obtained from the American College of Surgeons National Surgical Quality Improvement Program. Variables included in the original model included age, American Society of Anesthesiologists (ASA) class, functional status (independent or partially or totally dependent for any activities of daily living), preoperative dementia, preoperative delirium, and preoperative need for a mobility aid. To assess whether this model could be applied elsewhere, we used records from an international hip fracture registry. Between June 2017 and December 2018, 6672 patients older than 60 years of age in Australia and New Zealand were treated surgically for a femoral neck, intertrochanteric hip, or subtrochanteric hip fracture and entered into the Australian & New Zealand Hip Fracture Registry. Patients were excluded if they had a pathological hip fracture or septic shock. Of all patients, 6% (402 of 6672) did not meet the inclusion criteria, leaving 94% (6270 of 6672) of patients available for inclusion in this retrospective analysis. Seventy-one percent (4249 of 5986) of patients were aged 80 years or older, after accounting for 5% (284 of 6270) of missing values; 68% (4292 of 6266) were female, after accounting for 0.06% (4 of 6270) of missing values, and 83% (4690 of 5661) of patients were classified as ASA III/IV, after accounting for 10% (609 of 6270) of missing values. Missing data were imputed using the missForest methodology. In total, 39% (2467 of 6270) of patients developed postoperative delirium. The performance of the SORG hip fracture delirium algorithm on the validation cohort was assessed by discrimination, calibration, Brier score, and a decision curve analysis. Discrimination, known as the area under the receiver operating characteristic curves (c-statistic), measures the model's ability to distinguish patients who achieved the outcomes from those who did not and ranges from 0.5 to 1.0, with 1.0 indicating the highest discrimination score and 0.50 the lowest. Calibration plots the predicted versus the observed probabilities, a perfect plot has an intercept of 0 and a slope of 1. The Brier score calculates a composite of discrimination and calibration, with 0 indicating perfect prediction and 1 the poorest. Results The SORG hip fracture algorithm, when applied to an external patient cohort, distinguished between patients at low risk and patients at moderate to high risk of developing postoperative delirium. The SORG hip fracture algorithm performed with a c-statistic of 0.74 (95% confidence interval 0.73 to 0.76). The calibration plot showed high accuracy in the lower predicted probabilities (intercept -0.28, slope 0.52) and a Brier score of 0.22 (the null model Brier score was 0.24). The decision curve analysis showed that the model can be beneficial compared with no model or compared with characterizing all patients as at risk for developing delirium. Conclusion Algorithms developed with machine learning are a potential tool for refining treatment of at-risk patients. If high-risk patients can be reliably identified, resources can be appropriately directed toward their care. Although the current iteration of SORG should not be relied on for patient care, it suggests potential utility in assessing risk. Further assessment in different populations, made easier by international collaborations and standardization of registries, would be useful in the development of universally valid prediction models. The model can be freely accessed at: https://sorg-apps.shinyapps.io/hipfxdelirium/

Impact of Age on Consent in a Geriatric Orthopaedic Trauma Patient Population.

Introduction: Persistent misconceptions of frailty and dementia in geriatric patients impact physician-patient communication and leave patients vulnerable to disempowerment. Physicians may inappropriately focus the discussion of treatment options to health care proxies instead of patients. Our study explores the consenting process in a decision-making capable orthogeriatric trauma patient population to determine if there is a relationship between increased patient age and surgical consent by health care proxy. Methods: Patients aged 65 and older who underwent operative orthopaedic fracture fixation between 1 of 2 Level 1 Trauma Centers were retrospectively reviewed. Decision-making capable status was defined as an absence of patient history of cognitive impairment and a negative patient pre-surgical Confusion Assessment Method (CAM) and Mini-Cog Assessment screen. Provider of surgical consent was the main outcome and was determined by signature on the consent form. Results: 510 patients were included, and 276 (54.1%) patients were deemed capable of consent. In 27 (9.8%) of 276 decision-capable patients, physicians obtained consent from health care proxies. 20 of these 27 patients (74.1%) were 80 years of age or older. However, in patients aged 70 to 79, only 7 health care proxies provided consent. (p = 0.07). For every unit increase in age, the log odds of proxy consent increased by .0008 (p \u3c 0.001). Age (p \u3c 0.001), income level (p = 0.03), and physical presence of proxy at consult (p \u3c 0.001) were factors associated with significantly increased utilization of health care proxy provided consent. Language other than English was a significant predictor of proxy-provided consent (p = 0.035). 48 (22%) decision-making incapable patients provided their own surgical consent. Discussion: The positive linear association between age and health care proxy provided consent in cognitively intact geriatric orthopaedic patients indicates that increased patient age impacts the consenting process. Increased physician vigilance and adoption of institutional consenting guidelines can reinforce appropriate respect of geriatric patients\u27 consenting capacity

Epidemiology and outcome of rib fractures:a nationwide study in the Netherlands

Purpose Rib fractures following thoracic trauma are frequently encountered injuries and associated with a significant morbidity and mortality. The aim of this study was to provide current data on the epidemiology, in-hospital outcomes and 30-day mortality of rib fractures, and to evaluate these results for different subgroups. Methods A nationwide retrospective cohort study was performed with the use of the Dutch Trauma Registry which covers 99% of the acutely admitted Dutch trauma population. All patients aged 18 years and older admitted to the hospital between January 2015 and December 2017 with one or more rib fractures were included. Incidence rates were calculated using demographic data from the Dutch Population Register. Subgroup analyses were performed for flail chest, polytrauma, primary thoracic trauma, and elderly patients. Results A total of 14,850 patients were admitted between 2015 and 2017 with one or more rib fractures, which was 6.0% of all trauma patients. Of these, 573 (3.9%) patients had a flail chest, 4438 (29.9%) were polytrauma patients, 9273 (63.4%) were patients with primary thoracic trauma, and 6663 (44.9%) were elderly patients. The incidence rate of patients with rib fractures for the entire cohort was 29 per 100.000 person-years. The overall 30-day mortality was 6.9% (n = 1208) with higher rates observed in flail chest (11.9%), polytrauma (14.8%), and elderly patients (11.7%). The median hospital length of stay was 6 days (IQR, 3-11) and 37.3% were admitted to the intensive care unit (ICU). Conclusions Rib fractures are a relevant and frequently occurring problem among the trauma population. Subgroup analyses showed that there is a substantial heterogeneity among patients with rib fractures with considerable differences regarding the epidemiology, in-hospital outcomes, and 30-day mortality

Association of Patient-reported Outcomes with Clinical Outcomes after Distal Humerus Fracture Treatment

In this study, we assessed the patient-reported outcomes of distal humerus fracture treatment using Patient-Reported Outcomes Measurement Information System (PROMIS) or QuickDASH (Disabilities of the Arm, Shoulder, and Hand) scores and the association between patient-reported outcomes and clinical outcomes. Methods: We performed a retrospective cohort study of 76 adult patients who sustained an acute distal humerus fracture between 2016 and 2018; 53 patients completed at least one patient-reported outcome measure used to assess physical function (PF) during their routine follow-up care (69.7% response rate). The average time to follow-up patient-reported outcome measure was 10.3 months. Patients completed the PROMIS PF 10a, PROMIS upper extremity (UE) 16a, and/or QuickDASH based on the treating institution/service. In addition, the PROMIS Global (Mental) subscale score was used as a measure of self-rated mental health. To assess clinical outcomes, we measured radiographic union, range of motion, and postoperative complications. Results: Most fractures were intra-articular (67.9%), and 84.9% were treated surgically. After treatment, 98.1% of fractures united radiographically. By the final follow-up, the average arc of motion was 18° to 122°. Average (±SD) PROMIS PF and UE scores were 41.7 ± 11.1 and 40.8 ± 12.4, respectively. The average QuickDASH score was 39.4 ± 26.5. The arc of flexion-extension and PROMIS Global (Mental) score were independently associated with PROMIS PF and PROMIS UE scores. Conclusions: We found that clinical factors (the arc of flexion-extension) and patient psychological factors (PROMIS Global [Mental] score) were independently associated with PROMIS measures of PF after distal humerus fracture treatment. These data can be used to contextualize patient outcomes and guide patient expectations

The use of patient-reported outcome measures in the literature on traumatic foot fractures: A systematic review

Introduction: Adequate foot function is paramount in daily activities, yet the incidence of foot fractures shows a rising trend. Patient-reported outcome measures are increasingly used for research; however, the use of a wide variety of available instruments is undesirable. In the current study, an overview is provided of patient-reported outcome measures used in clinical research evaluating outcomes of foot fractures. Tools are provided to choose the most adequate instrument in future research. Methods: To identify the instruments, a systematic review was performed using PubMed, Embase, and the Cochrane Library. Articles published since 2000, reporting on traumatic foot fractures and/or their posttraumatic sequelae, and using a minimum of one condition- or region-specific patient-reported outcome measure were included. Forty-nine instruments were identified, used 636 times collectively. These instruments were evaluated on frequency of use, bones or joints analyzed with the instruments, the type and amount of contained items, and existing literature on their psychometric properties. Results: The American Orthopaedic Foot and Ankle Society Ankle-Hindfoot Scale was used predominantly (AOFAS Ankle-Hindfoot Scale; n = 243, 38.2%), followed by the Maryland Foot Score (n = 90, 14.2%). Twenty-seven instruments were included for further analysis. The majority included questions on mobility (27/27) and pain (24/27). Tools to select an adequate instrument for new research are presented in the appendices. Discussion: Controversy surrounds the AOFAS Ankle-Hindfoot Scale as other authors have found that its psychometric properties, indicating it measures what it is supposed to measure adequately, are flawed. Conclusion: A multitude of specific patient-reported outcome measures concerning foot fractures exists. Furthermore, the predominantly used instrument is deemed insufficient regarding quality as found by other studies. A valid, reliable, and responsive patient-reported outcome measure for clinical research on foot fractures is necessary. The most adequate existing ones for future research on different topics can be found through the tools provided

Rib fractures in the elderly population: a systematic review

Background: Multiple rib fractures are associated with significant morbidity and mortality, especially in elderly patients. There is growing interest in surgical stabilization in this subgroup of patients. This systematic review compares conservative treatment to surgical fixation in elderly patients (older than 60 years) with multiple rib fractures. The primary outcome is mortality. Secondary outcomes include hospital and intensive care length of stay (HLOS and ILOS), duration of mechanical ventilation (DMV) and pneumonia rates. Methods: Multiple databases were searched for comparative studies reporting on conservative versus operative treatment for rib fractures in patients older than 60 years. Both observational studies and randomised clinical trials were considered. Results: Five observational studies (n = 2583) were included. Mortality was lower in operatively treated patients compared to conservative treatment (4% vs. 8%). Pneumonia rate and DMV were similar (5/6% and 5.8/6.5 days) for either treatment modality. Overall ILOS and HLOS of stay were longer in operatively treated patients (6.5 ILOS and 12.7 HLOS vs. 2.7 ILOS and 6.5 ILOS). There were only minimal reports on perioperative complications. Notably, the median number of rib fractures (8.4 vs. 5) and the percentage of flail chest were higher in operatively treated patients (47% vs. 39%). Conclusion: It remains unknown to what extent conservative and operative treatment contribute individually to reducing morbidity and mortality in the elderly with multiple rib fractures. To date, the quality of evidence is rather low, thus well-performed comparative observational studies or randomised controlled trials considering all confounders are needed to determine whether operative treatment can improve a patient’s outcome