Rheological transition in simple shear of moderately dense assemblies of dry cohesive granules

The rheology of homogeneous cohesive granular assemblies under shear at moderate volume fractions is investigated using the discrete element method for both frictionless and frictional granules. A transition in rheology from inertial to quasistatic scaling is observed at volume fractions below the jamming point of noncohesive systems, which is a function of the granular temperature, energy dissipation, and cohesive potential. The transition is found to be the result of growing clusters, which eventually percolate the domain, and change the mode of momentum transport in the system. Differences in the behavior of the shear stress normalized by the pressure are observed when frictionless and frictional cases are compared. These differences are explained through contact anisotropy after percolation occurs. Both frictionless and frictional systems are found to be vulnerable to instabilities after full system percolation has occurred, where the former becomes thermodynamically unstable and the latter may form shear bands. Finally, implications for constitutive modeling are discussed.

Scarf osteotomy without internal fixation for correction of hallux valgus: A clinical and radiographic review of 148 cases

BACKGROUND

Hallux valgus is a common condition with in excess of 120 procedures described in the literature for its correction. Traditionally, distal metatarsal osteotomies have been employed in the treatment of mild deformities, with proximal osteotomies being reserved for more severe presentations. The Scarf osteotomy without internal fixation allows large translations which can successfully correct severe hallux valgus deformities, without limitations related to screw placement.

METHODS

This is a retrospective single surgeon case series performed over a three year period. One hundred and forty-eight cases were identified, with an average follow up time of 16.5 months. Visual analogue scales were used to obtain preoperative and postoperative pain and cosmetic scores, with the Foot and Ankle Disability Index (FADI) index used to assess functional status. The hallux valgus angle (HVA) and intermetatarsal angle (IMA) were assessed on preoperative and postoperative AP weight-bearing foot X-rays.

RESULTS

The mean pain score improved from 7.04/10 preoperatively to 0.29/10 postoperatively. The mean cosmetic score improved from 2.1/10 to 9.1/10 postoperatively. The mean preoperative HVA and IMA were 35.04° and 15.04°, respectively. The mean postoperative HVA and IMA were 11.54° and 4.83°, respectively. The mean postoperative FADI score was 103.4/104. We report a loss of correction in two cases. One revision surgery was performed.

CONCLUSIONS

We report a large series of cases of the modified Scarf osteotomy as described by Maestro-a versatile, cost-effective, safe and reliable technique with the potential for three dimensional correction. Whilst this is a technically demanding procedure, we recommend the use of the modified Scarf osteotomy in the treatment of a wide range of hallux valgus deformities.

Extracorporeal Membrane Oxygenation as a Bridge to Lung Transplantation in Patients Over Age 70 Years: A Case Report

Extracorporeal membrane oxygenation (ECMO) may be used safely as a bridge to lung transplantation in carefully selected elderly patients. We report the case of a 70-year-old patient bridged on ECMO before transplantation. A brief discussion on improving outcomes for the elderly and patients bridged on ECMO in general is presented.

UX007 for the treatment of long chain-fatty acid oxidation disorders: Safety and efficacy in children and adults following 24weeks of treatment

BACKGROUND

Long-chain fatty acid oxidation disorders (LC-FAOD) lead to accumulation of high concentrations of potentially toxic fatty acid intermediates. Newborn screening and early intervention have reduced mortality, but most patients continue to experience frequent hospitalizations and significant morbidity despite treatment. The deficient energy state can cause serious liver, muscle, and heart disease, and may be associated with an increased risk of sudden death. Triheptanoin is a medium odd-chain fatty acid. Anaplerotic metabolites of triheptanoin have the potential to replace deficient tricarboxylic acid (TCA) cycle intermediates, resulting in net glucose production as a novel energy source for the treatment of LC-FAOD.

STUDY DESIGN

A single-arm, open-label, multicenter Phase 2 safety and efficacy study evaluated patients with severe LC-FAOD evidenced by ongoing related musculoskeletal, cardiac, and/or hepatic events despite treatment. After a four-week run-in on current regimen, investigational triheptanoin (UX007) was titrated to a target dose of 25-35% of total daily caloric intake. Patients were evaluated on several age/condition-eligible endpoints, including submaximal exercise tests to assess muscle function/endurance (12-minute walk test; 12MWT) and exercise tolerance (cycle ergometry), and health related quality of life (HR-QoL). Results through 24weeks of treatment are presented; total study duration is 78weeks.

RESULTS

Twenty-nine patients (0.8 to 58years) were enrolled; most qualified based on severe musculoskeletal disease. Twenty-five patients (86%) completed the 24-week treatment period. At Week 18, eligible patients (n=8) demonstrated a 28% increase (LS mean=+181.9 meters; p=0.087) from baseline (673.4meters) in 12MWT distance. At Week 24, eligible patients (n=7) showed a 60% increase in watts generated (LS mean=+409.3W; p=0.149) over baseline (744.6W) for the exercise tolerance test. Improvements in exercise tests were supported by significant improvements from baseline in the adult (n=5) self-reported SF-12v2 physical component summary score (LS mean=+8.9; p<0.001). No difference from baseline was seen in pediatric parent-reported (n=5) scores (SF-10) at Week 24. Eighteen patients (62%) had treatment-related adverse events, predominantly gastrointestinal (55%), mild-to-moderate in severity, similar to that seen with prior treatment with medium chain triglyceride (MCT) oil. One patient experienced a treatment-related serious adverse event of gastroenteritis. One patient discontinued from study due to diarrhea of moderate severity; the majority of patients (25/29; 86%) elected to continue treatment in the extension period.

CONCLUSIONS

In patients with severe LC-FAOD, UX007 interim study results demonstrated improved exercise endurance and tolerance, and were associated with positive changes in self-reported HR-QoL.

Predictors of developmental surveillance completion at six months of age in south western Sydney

BACKGROUND

While developmental surveillance programs promote early identification of child developmental problems, evidence has indicated suboptimal uptake. This study aimed to identify predictors of developmental surveillance completion at 6 months postpartum.

METHODS

Questionnaires were administered to the parents of 510 infants who were born in south western Sydney, Australia over a 22-month period. Attendance for developmental screening and completion of the Parents' Evaluation of Developmental Status (PEDS) at 6 months postpartum were modelled separately using multivariable logistic regression.

RESULTS

Developmental surveillance attendance was predicted by higher levels of maternal education, annual income and being informed about checks. PEDS completion at 6 months of age was predicted by higher income and being informed, as well as being married, employed, speaking English at home, full-term birth and the professional status of the practitioner completing the check.

CONCLUSIONS

Barriers to developmental surveillance included low socioeconomic status, linguistic diversity and possible gaps in parental knowledge and professional education. Developmental surveillance rates may be increased by the addition of targeted parental and professional support within current universal frameworks.

Early results of the LPS™ limb preservation system in the management of periprosthetic femoral fractures

INTRODUCTION

Achieving skeletal fixation in the presence of progressive bone loss is a surgical challenge, especially in cases of periprosthetic fracture (PPF). Unpredictable fracture patterns and preexisting bone loss frequently combine in this patient group. Megaprosthetic arthroplasty allows for immediate mobilisation and shorter periods of rehabilitation. We describe the clinical outcomes of a cohort of LPS™ megaprostheses performed for PPF by a single surgeon at our institution.

METHODS

Between July 2013 and November 2015, 23 patients underwent endoprosthetic femoral replacement of which 16 were performed for PPF or bone loss. Patient demographics, surgical indication, operative details, implant composition, blood loss, survival, and revision surgery details were recorded in a prospectively maintained database. Patients underwent serial clinical and X-ray evaluations at 6 weeks, 3 months and 6 months post surgery with yearly reviews thereafter.

RESULTS

The PPF cohort consisted of 9 males and 7 females with a mean age of 75 and a mean follow up of 19.2 months. The mean Oxford score prior to fracture was 41 (range 12-48), and 39 (range 13-48, p = 0.6) post megaprosthesis insertion. Postoperative dislocation of the megaprosthesis occurred in two patients (12.5%), with no postoperative infections recorded.

CONCLUSION

We report minimal postoperative changes in functional outcome scores. The results of revision arthroplasty with LPS™ proximal femur megaprosthesis were satisfactory in 15/16 patients at a mean follow-up of 19.2 months. We recommend the use of megaprostheses in patients with markedly deficient bone stock for whom other available reconstructive procedures are unavailable.

Arthrodesis of Little Finger Distal Interphalangeal Joint in Flexion to Regain Sporting Ability

BACKGROUND

Finger injuries are common in the sport of hurling. Injury to the little finger distal interphalangeal joint (DIPJ) often occurs when a high dropping ball impacts on the outstretched finger. The little finger contributes to approximately 15% of grip strength. Injury therefore results in reduced grip strength and may impair the ability of players to grip or catch a ball.

METHODS

Six elite hurlers with post-traumatic arthritis of their non-dominant little finger DIPJ underwent arthrodesis in 30 degrees of flexion. Kirchner wires were inserted for up to 8 weeks to achieve fusion of the joint. Patients were evaluated after recovery using a dynamometer to assess grip strength, the DASH questionnaire and a sport specific questionnaire.

RESULTS

All arthrodeses achieved bony union without complication. All patients reported a resolution of their pain and recovery in their ability to catch & retain a ball. Measurements of grip strengths were comparable between hands. DASH scores improved by up to 47 points. All scores were less than 5 at final follow-up.

CONCLUSIONS

Grip strength decreases when fingers are immobilized in full extension. In sports that require catching or gripping a ball or a bat, arthrodesis of the DIP joint in flexion can improve grip strength and hand function. Fusion in 30 degrees of flexion for hurlers results in restoration of function and resolution of pain. Little finger DIPJ arthrodesis is a valid method of treating posttraumatic arthritis in ball and bat sports.

Medium term review of the ASR implant system: A single surgeon series

INTRODUCTION

Both ASR hip resurfacings and stemmed ASR XL arthroplasties have failed at high rates in several published series. We assessed a single surgeon series of these arthroplasties looking to identify factors associated with their failure.

METHODS

All surgeries were performed by one surgeon. Patients were evaluated clinically, radiologically and with serial cobalt and chromium ion analysis.

RESULTS

274 implants were analysed - 152 ASR resurfacings and 122 ASR XL implants. Thirty revisions were performed.

CONCLUSION

The failure rate of the ASR implant in our series is unacceptably high - its use in routine hip arthroplasty cannot be supported.

Reducing risks of Transfusion-transmitted infections in a resource-limited hospital-based blood bank: the case of the Yaoundé University Teaching Hospital, Cameroon

BACKGROUND AND OBJECTIVES

Although interest in assessing risk of TTIs, very few trends in blood safety epidemiological data from resource-limited blood services are reported in the literature. This analysis aims at reporting trends in seroprevalences of TTIs in blood donations in the Yaoundé University Teaching Hospital (UTH) from 2011 to 2015 and to describe reasons for these changes.

MATERIALS AND METHODS

All donations of 2015 were tested for HIV 1&2 antibodies and the P24 antigen, HBsAg, HCV antibody and the Treponema pallidum antibody. Screening for HIV uses a national algorithm based on the systematic use of two assays of different principles: a rapid determination testing assay and an EIA HIV 1 & 2 Ab-Ag. The tests used for HBsAg and HCVAb screening were all based on EIA techniques. Treponema pallidum antibody screening was based on Treponema Pallidum hemagglutination assay (TPHA) and rapid immunochromatographic test (RIT). Screening techniques and results from 2015 were compared to retrospective data from 2011, 2012, 2013 and 2014.

RESULTS

In 2015, 13·4% (n = 214) of 1,596 blood donations were seropositive for at least one screened TTIs. The most frequent serological marker was HBsAg with 123 (7·7%) blood units contaminated. Nineteen (1·2%) and 18 (1·1%) blood units was positive for HIV and syphilis, respectively. There was a significant decrease in the total number of blood donations (P < 10^-4) and HIV, HBsAg and syphilis seroprevalences and an increase in the proportion of voluntary non-remunerated blood donor (P < 0·05). HCVAb seroprevalence was 3·8% in 2015 and has not decreased significantly over the years (P = 0·09).

CONCLUSION

Significant progress is noted in reduction in seroprevalences of HIV, HBV, HCV and syphilis since the beginning of a regular registration of data in 1990.

Source-based subjective responses to sleep disturbance from transportation noise

There is increasing evidence to suggest that the use of subjective responses to questions concerning night-time environmental noise exposure is a robust method of assessing sleep disturbance from road traffic noise. However, there have only been a few studies exploring this issue in a real world context beyond controlled laboratory settings. This paper presents results from such a study. It utilises 208 household questionnaire surveys to assess subjective responses to levels of night-time sleep disturbance and annoyance from four different residential sites. Each residential site is characterised by a dominant noise source - road, light rail, and aircraft - and these sites are compared to a control site that is relatively free from transportation noise. The results demonstrate the inadequacy of continuous equivalent noise level measures as indicators of night-time disturbance. Furthermore, they suggest that the use of these measures alone is likely to result in inaccurate appraisals of night-time sleep disturbance from transportation noise. Ultimately, the research implies that measurement data should be used in conjunction with subjective response data to accurately gauge the level of night-time disturbance from transportation noise.

Financial impact of allogeneic hematopoietic cell transplantation on patients and families over 2 years: results from a multicenter pilot study

Hematopoietic cell transplantation (HCT) is a procedure that can significantly influence the socioeconomic wellbeing of patients, caregivers and their families. Among 30 allogeneic HCT recipients and their caregivers enrolled on a pilot study evaluating the feasibility of studying financial impact of HCT, 16 agreed to participate in the long-term phase, completed a baseline questionnaire and received phone interviews at 6, 12, 18 and 24 months post-HCT. Analyses showed that by 2-years post-HCT, 54% of patients who previously contributed to household earnings had not returned to work and 80% of patients/caregivers reported transplant as having moderate to great impact on household income. However, patients’ level of confidence in their ability to meet household financial obligations increased from baseline to 2-years. A relatively large proportion of patients reported inability to pay for medical care through this time period. Case studies demonstrated patient individual perception of financial impact of HCT varies considerably, regardless of actual income. We demonstrate the feasibility of conducting a study to evaluate financial impact of allogeneic HCT through 2-years post-transplantation. Some patients/caregivers continue to experience significant long-term financial burden after this procedure. Our study lays the foundation for a larger evaluation of patient/caregiver financial burden associated with HCT.