Dust and Death: Evidence from the West African Harmattan.

Using two decades of data from 12 low-income countries in West Africa, we show that dust carried by harmattan trade winds increases infant and child mortality. Health investments respond to dust exposure, consistent with compensating behaviours. Despite these efforts, surviving children still exhibit negative health impacts. Our data allow us to investigate differential impacts over time and across countries. We find declining impacts over time, suggesting adaptation. Using national-level measures of macroeconomic conditions and health resources, we find suggestive evidence that both economic development and public health improvements have contributed to this adaptation, with health improvements playing a larger role.

A 1RM Strengthening and Exercise Programme for the Treatment of Knee Osteoarthritis: A Quality-Improvement Study.

Background: The Kneefit programme is a 12-week strengthening and exercise programme, personalised using body-weight ratios, for people with knee osteoarthritis. Objectives and Design: This quality-improvement study was conducted to evaluate the effectiveness of the programme for managing symptomatic knee osteoarthritis. Methods: The Kneefit programme was delivered between 20 August 2013 and 7 January 2014 and included six weeks of supervised strengthening, balance, and cardiovascular exercise in a group at the local hospital, followed by six weeks of unsupervised exercise. Leg-press and knee-extension 1RM scores were assessed at baseline, six weeks, and twelve weeks. In addition, patient-reported outcome measures (Oxford Knee Score, EQ5D, Patient Specific Function Score (PSFS)) were assessed. Wilcoxon Signed Rank tests were used to evaluate the changes from week 1 to week 6 and week 12. Results: Thirty-six patients were included at baseline and at six weeks, and 31 patients completed their twelve-week assessment. Statistically significant improvements were found at 6 and 12 weeks for change for the Oxford Knee Score (median change: 4.0, IQR 4.0 to 9.0, p < 0.001 and 4.0, IQR 0 to 8.0, p < 0.001), EQ5D-5L (median change: 0.078, IQR 0.03 to 0.20, p < 0.001 and 0.071, IQR 0.02 to 0.25, p < 0.001) and the PSFS (median change: 1.3 IQR 0 to 2.6, p = 0.005 and 2.3 IQR -0.3 to 3.3, p = 0.016). In addition, significant improvements were found for 1RM leg-press and knee-extension scores on both the affected and unaffected legs. Conclusion: The Kneefit programme was successful at improving both functional and strength-related outcome measures in patients with knee osteoarthritis. Our findings suggest that tailoring strength exercises based on the 1RM strength-training principles is feasible in this population.

Deploying machine learning with messy, real world data in low- and middle-income countries: Developing a global health use case.

The rapid emergence of machine learning in the form of large-scale computational statistics and accumulation of data offers global health implementing partners an opportunity to adopt, adapt, and apply these techniques and technologies to low- and middle-income country (LMIC) contexts where we work. These benefits reside just out of the reach of many implementing partners because they lack the experience and specific skills to use them. Yet the growth of available analytical systems and exponential growth of data require the global digital health community to become conversant in this technology to continue to make contributions to help fulfill our missions. In this community case study, we describe the approach we took at IntraHealth International to inform the use case for machine learning in global health and development. We found that the data needed to take advantage of machine learning were plentiful and that an international, interdisciplinary team can be formed to collect, clean, and analyze the data at hand using cloud-based (e.g., Dropbox, Google Drive) and open source tools (e.g., R). We organized our work as a "sprint" lasting roughly 10 weeks in length so that we could rapidly prototype these approaches in order to achieve institutional buy in. Our initial sprint resulted in two requests in subsequent workplans for analytics using the data we compiled and directly impacted program implementation.

A Single Dose Versus Two Doses of Tranexamic Acid for Extracapsular Hip Fractures.

Objective In this study, we aimed to compare the effectiveness of one dose of tranexamic acid (TXA) at the time of hospital admission versus two doses of TXA (one at the time of hospital admission and another dose intraoperatively) in reducing perioperative total blood loss in patients with extracapsular hip fractures. Methods This retrospective cohort study included 80 patients from a single institution who underwent surgical fixation for extracapsular hip fractures. Forty patients received a single dose of 1 gram of TXA at the time of hospital admission (per standardized protocol of an ongoing research study at the time), and 40 patients received the same dose of TXA on hospital admission as well as a second dose of 1 gram of TXA intraoperatively at the time of incision (per standard practice change following the completion of the research study). The primary study outcome of interest was total blood loss, which was calculated by estimating blood volume via Nadler's formula followed by calculating the total blood loss with the hemoglobin dilution method. Secondary outcomes included blood transfusion rates, hospital length of stay (LOS), and 30-day mortality. Results Patient gender, age, the American Society of Anesthesiologists (ASA) score, procedure length, fracture type, hardware type, and hemoglobin on hospital arrival were similar across the study groups (all p>0.05), though the twice-dosed group had a higher average BMI (26.4 kg/m2 vs. 24 kg/m2, p=0.04). When adjusting for BMI, the twice-dosed group was estimated to have a slightly larger but non-significant difference in total blood loss (115-ml difference, 95% CI: 158.2-389.3, p=0.40) compared to the single-dose TXA group. More patients in the twice-dosed group required blood transfusion compared to the single-dose TXA group, though this was not statistically significant (30.0% vs. 17.5%, adjusted OR=1.64, 95% CI: 0.55-5.12, p=0.38). The distribution of hospital LOS and 30-day mortality rates were similar across the groups (p=0.13 and p>0.99). Conclusion In the setting of surgically treated extracapsular hip fractures, patients who received one dose of TXA at the time of hospital admission and a second intraoperative dose of TXA did not demonstrate significant differences in total blood loss or a need for blood transfusion compared to patients who only received a single dose of TXA at the time of hospital admission.

Hyaluronan Receptor LYVE-1-Expressing Macrophages Maintain Arterial Tone through Hyaluronan-Mediated Regulation of Smooth Muscle Cell Collagen.

The maintenance of appropriate arterial tone is critically important for normal physiological arterial function. However, the cellular and molecular mechanisms remain poorly defined. Here, we have shown that in the mouse aorta, resident macrophages prevented arterial stiffness and collagen deposition in the steady state. Using phenotyping, transcriptional profiling, and targeted deletion of Csf1r, we have demonstrated that these macrophages-which are a feature of blood vessels invested with smooth muscle cells (SMCs) in both mouse and human tissues-expressed the hyaluronan (HA) receptor LYVE-l. Furthermore, we have shown they possessed the unique ability to modulate collagen expression in SMCs by matrix metalloproteinase MMP-9-dependent proteolysis through engagement of LYVE-1 with the HA pericellular matrix of SMCs. Our study has unveiled a hitherto unknown homeostatic contribution of arterial LYVE-1+ macrophages through the control of collagen production by SMCs and has identified a function of LYVE-1 in leukocytes.

Effect of degeneration on the six degree of freedom mechanical properties of human lumbar spine segments.

While the effects of disc degeneration on compression and rotation motions have been studied, there is no data for shear loading. Clinical research has shown that those with low back pain (a potential consequence of degeneration) experience a 75% greater lateral shear force than those without it. Therefore, the aim was to compare the effect of degeneration on spine segment stiffness and phase angle in each of six degree of freedom (6DOF) loading directions. Fourteen intact functional spinal units (FSU) were dissected from human lumbar spines (mean (SD) age 76.2 (11) years, Thompson grades 3 (N = 5, mild), 4 (N = 6, moderate), 5 (N = 3, severe)). Each FSU was tested in ±6DOFs while subjected to a physiological preload, hydration, and temperature (37°C) conditions in a hexapod robot. A one-way ANOVA between degenerated groups was performed on stiffness and phase angle for each DOF. Significant differences in stiffness were found between mild and moderate degenerative groups in lateral shear (p = 0.001), and axial rotation (p = 0.001), where moderate degeneration had decreased stiffness. For phase angle, significant differences were seen in anterior shear (p = 0.017), and axial rotation (p = 0.026), where phase angle for mild degeneration was less than moderate. Trends of stiffness and phase angle changes between degenerative groups were similar within each DOF. Clinically, the identification of the DOFs that are most affected by degeneration could be used in rehabilitation to improve supplemental stabilization of core muscle groups. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1399-1409, 2016.

Effect of potting technique on the measurement of six degree-of-freedom viscoelastic properties of human lumbar spine segments.

Polymethyl methacrylate (PMMA) and Wood's Metal are fixation media for biomechanical testing; however, the effect of each potting medium on the measured six degree-of-freedom (DOF) mechanical properties of human lumbar intervertebral discs is unknown. The first aim of this study was to compare the measured 6DOF elastic and viscoelastic properties of the disc when embedded in PMMA compared to repotting in Wood's Metal. The second aim was to compare the surface temperature of the disc when potted with PMMA and Wood's Metal. Six human lumbar functional spinal units (FSUs) were first potted in PMMA, and subjected to overnight preload in a saline bath at 37 °C followed by five haversine loading cycles at 0.1 Hz in each of 6DOF loading directions (compression, left/right lateral bending, flexion, extension, left/right axial rotation, anterior/posterior, and lateral shear). Each specimen was then repotted in Wood's Metal and subjected to a 2-h re-equilibrating preload followed by repeating the same 6DOF tests. Outcome measures of stiffness and phase angle were calculated from the final loading cycle in each DOF and were expressed as normalized percentages relative to PMMA (100%). Disc surface temperatures (anterior, left/right lateral) were measured during potting. Paired t-tests (with alpha adjusted for multiple DOF) were conducted to compare the differences in each outcome parameter between PMMA and Wood's Metal. No significant differences in stiffness or phase angle were found between PMMA and Wood's Metal. On average, the largest trending differences were found in the shear DOFs for both stiffness (approximately 35% greater for Wood's Metal compared to PMMA) and phase angle (approximately 15% greater for Wood's Metal). A significant difference in disc temperature was found at the anterior surface after potting with Wood's Metal compared to PMMA, which did not exceed 26 °C. Wood's Metal is linear elastic, stiffer than PMMA and may reduce measurement artifact of potting medium, particularly in the shear directions. Furthermore, it is easier to remove than PMMA, reuseable, and cost effective.

A novel method to replicate the kinematics of the carpus using a six degree-of-freedom robot.

Understanding the kinematics of the carpus is essential to the understanding and treatment of wrist pathologies. However, many of the previous techniques presented are limited by non-functional motion or the interpolation of points from static images at different postures. We present a method that has the capability of replicating the kinematics of the wrist during activities of daily living using a unique mechanical testing system. To quantify the kinematics of the carpal bones, we used bone pin-mounted markers and optical motion capture methods. In this paper, we present a hammering motion as an example of an activity of daily living. However, the method can be applied to a wide variety of movements. Our method showed good accuracy (1.0-2.6°) of in vivo movement reproduction in our ex vivo model. Most carpal motion during wrist flexion-extension occurs at the radiocarpal level while in ulnar deviation the motion is more equally shared between radiocarpal and midcarpal joints, and in radial deviation the motion happens mainly at the midcarpal joint. For all rotations, there was more rotation of the midcarpal row relative to the lunate than relative to the scaphoid or triquetrum. For the functional motion studied (hammering), there was more midcarpal motion in wrist extension compared to pure wrist extension while radioulnar deviation patterns were similar to those observed in pure wrist radioulnar deviation. Finally, it was found that for the amplitudes studied the amount of carpal rotations was proportional to global wrist rotations.

Assessment of the initial viscoelastic properties of a critical segmental long bone defect reconstructed with impaction bone grafting and intramedullary nailing.

INTRODUCTION: This study compared the initial viscoelastic properties of a segmental tibial defect stabilized with intramedullary nailing and impaction bone grafting to that of a transverse fracture stabilized with intramedullary nailing. MATERIALS AND METHODS: Seven sheep tibiae were tested in compression (1000N), bending and torsion (6Nm) in a six degree-of-freedom hexapod robot. Tests were repeated across three groups: intact tibia (Intact), transverse fracture stabilized by intramedullary nailing (Fracture), and segmental defect stabilized with a nail and impaction bone grafting (Defect). Repeated measures ANOVA on the effect of group on stiffness/phase angle were conducted for each loading direction. RESULTS: The Intact group was significantly stiffer than the Fracture and Defect groups in bending and torsion (p<0.022 for both loading directions), and was marginal for the Defect group in compression (p=0.052). No significant differences were found between the Fracture and Defect groups (p>0.246 for all loading directions) for stiffness/phase angle. In compression and bending, phase angles were significantly greater for the Fracture and Defect groups compared to Intact (p<0.025), with no significant differences between groups in torsion (p=0.13). Sensitivity analyses conducted between the Fracture and Defect group differences found that they were not of clinical significance. CONCLUSION: The initial properties of a segmental defect stabilized with intramedullary nailing and impaction bone grafting was not clinically significantly different to that of a transverse fracture stabilized with intramedullary nailing.

Stem micromotion after femoral impaction grafting using irradiated allograft bone: a time zero in vitro study.

BACKGROUND: A gamma irradiation dose of 15kGy has been shown to adequately sterilise allograft bone, commonly used in femoral impaction bone grafting to treat bone loss at revision hip replacement, without significantly affecting its mechanical properties. The objective of this study was to evaluate whether use of 15kGy irradiated bone affects the initial mechanical stability of the femoral stem prosthesis, as determined by micromotion in a comprehensive testing apparatus, in a clinically relevant time zero in vitro model of revision hip replacement. METHODS: Morselised ovine bone was nonirradiated (control), or irradiated at 15kGy or 60kGy. For each dose, six ovine femurs were implanted with a cemented polished taper stem following femoral impaction bone grafting. Using testing apparatus that reproduces stem loading, stems were cyclically loaded and triaxial micromotion of the stem relative to the bone was measured at the proximal and distal stem regions using non-contact laser transducers and linear variable differential transformers. FINDINGS: There were no significant differences in proximal or distal stem micromotion between groups for all directions (p≤0.80), apart for significantly greater distal stem medial-lateral micromotion in the 60kGy group compared to the 15kGy group (P=0.03), and near-significance in the anterior-posterior direction (P=0.08, power=0.85). INTERPRETATION: Using a clinically relevant model and loading apparatus, irradiation of bone at 15kGy does not affect initial femoral stem stability following femoral impaction bone grafting.

Behind the estimates of out-of-pocket spending on health in the former Soviet Union

The countries of the former Soviet Union rely heavily on out-of-pocket payments for health care financing. However, out-of-pocket spending statistics are difficult to compare due to different data collection methodologies. Data are collected either through demand side data collection, via household surveys, or supply side data collection, via health clinics, pharmacies, and other suppliers’ data. This technical report is targeted at producers of out-of-pocket spending data, users of the WHO Global Health Expenditure Database and related publications as well as policy-makers, who wish to improve financial protection, on how to improve the relevant data through introduction of international standards of reporting such as the national health accounts. An analysis of former Soviet Union countries reveals that, all else being constant, countries that use national health accounts report 12% higher out-of-pocket spending. This is because national health accounts promotes the usage of detailed questions in surveys on household health care expenditures. Countries that rely solely on supply side information report 15% percent less out-of-pocket spending than countries with similar economic development and health priority status. The analysis strongly supports the view that national health accounts-based reporting usually based on specialized surveys increases the accuracy of out-of-pocket payments for health care.

The impact of tensioning device mal-positioning on strand tension during anterior cruciate ligament reconstruction.

BACKGROUND: In order to confer optimal strength and stiffness to the graft in Anterior Cruciate Ligament (ACL) reconstruction, the maintenance of equal strand tension prior to fixation, is desired; positioning of the tensioning device can significantly affect strand tension This study aimed to determine the effect of tensioning device mal-positioning on individual strand tension in simulated cadaveric ACL reconstructions. METHODS: Twenty cadaveric specimens, comprising bovine tibia and tendon harvested from sheep, were used to simulate ACL reconstruction with a looped four-strand tendon graft. A proprietary tensioning device was used to tension the graft during tibial component fixation with graft tension recorded using load cells. The effects of the tensioning device at extreme angles, and in various locking states, was evaluated. RESULTS: Strand tension varied significantly when the tensioning device was held at extreme angles (p < 0.001) or in 'locked' configurations of the tensioning device (p < 0.046). Tendon position also produced significant effects (p < 0.016) on the resultant strand tension. CONCLUSION: An even distribution of tension among individual graft strands is obtained by maintaining the tensioning device in an unlocked state, aligned with the longitudinal axis of the tibial tunnel. If the maintenance of equal strand tension during tibial fixation of grafts is important, close attention must be paid to positioning of the tensioning device in order to optimize the resultant graft tension and, by implication, the strength and stiffness of the graft and ultimately, surgical outcome.

Tibial interference screw fixation in anterior cruciate ligament reconstruction with and without autograft bone augmentation.

PURPOSE: Because tibial fixation of soft-tissue grafts in anterior cruciate ligament (ACL) reconstruction is problematic, this study aimed to develop a means of delivering bone graft evenly around tendon autograft and define any mechanical, radiologic, or histologic benefit using an ovine model. METHODS: A device to deliver bone graft evenly throughout the tibial tunnel was developed. Forty mature sheep underwent simulated quadruple hamstring tendon-ACL reconstruction by use of a bioresorbable interference screw, either with or without bone graft augmentation of the tibial tunnel. Endpoint data were derived at time 0 and after 6 weeks in vivo. Radiostereometric analysis provided quantitation of the translational characteristics; computed tomography evaluated tunnel volume, and measures of yield strength and stiffness were obtained. Sequential fluorochrome administration assessed bone formation, and light microscopy surveyed the biological response. RESULTS: Radiostereometric analysis highlighted differences in the translational characteristics of ACL-deficient knees when compared with intact knees. Reconstructed knees (with or without autograft) showed significantly greater translation when compared with unoperated knees at 6 weeks; autograft bone augmentation provided no benefit. Neither tunnel volume nor yield strength nor stiffness was improved with the addition of autograft bone. No untoward histologic responses were observed. Bone apposition rates were similar between treatment groups. An even distribution of bone graft throughout the tunnels was observed. CONCLUSIONS: This model has confirmed the ability of the bone graft-delivery system to evenly distribute bone graft throughout the tunnels. However, the study has failed to show improvement in stability or fixation strength after augmentation with autograft bone. CLINICAL RELEVANCE: The autograft bone-delivery system may provide a means of establishing an osteoconductive/inductive environment. At this early juncture (6 weeks), no benefit could be defined. Its use in combination with bone morphogenetic proteins or stem cells may provide more rapid fixation, rehabilitation, and reconstitution of bone volume within the tunnel.

Augmentation of tibial fixation of soft-tissue grafts in anterior cruciate ligament reconstruction.

PURPOSE: Fixation of the tibial aspect of soft-tissue grafts in anterior cruciate ligament (ACL) reconstruction is problematic. Augmentation of the interference fit in screw application is seen as a means of improving fixation. This study aims to determine the effect of mesh augmentation of interference screw application in ACL reconstruction. METHODS: Forty cadaveric ovine hind limbs were harvested at necropsy. A quadrupled hamstring tendon graft (QHT), used in human ACL reconstruction, was simulated. Metal and bioresorbable interference screws were used for tibial fixation in the presence or absence of mesh augmentation. Anterior translation of the reconstruction was determined via radiostereometric analysis; specimens were then subjected to tensile loading, with load to failure and mechanism of failure recorded. RESULTS: There was no improvement in biomechanical properties observed for either the metal or bioresorbable screws with mesh as evaluated by load to failure or anterior translation in this cadaveric model. CONCLUSIONS: The use of a synthetic mesh, encompassing the strands of a QHT and interference screw, did not significantly improve the strength or rigidity of the simulated ACL reconstruction performed. CLINICAL RELEVANCE: Metal interference screws have provided a more secure fixation in the QHT when compared with bioresorbable screws. Augmentation of the reconstruction, by the application of mesh in the tibial tunnel, proved difficult to apply with no observed benefit to either the mechanical or radiologic attributes of the reconstruction.

The effect of screw taper on interference fit during load to failure at the soft tissue/bone interface.

The effect of screw geometry on the pullout strength of an anterior cruciate ligament reconstruction is well documented. The effect of a truly tapered screw has not been previously investigated. Thirty bovine knees in right and left knee pairs were collected. Superficial digital flexors from the hind legs of sheep were harvested to form a quadruple tendon graft. For each knee pair, one tendon graft was fixed using a tapered screw (n=15) and the other with a non-tapered screw (n=15). Interference screws were manufactured from stainless steel, and apart from the tapered or non-tapered profile were identical. The screws were inserted into a tibial tunnel already containing the tendon graft. The interference fit was tested by extensile load to failure tests. The insertion torque of the screws and first sign of load to failure (by pullout) of the interference fit were recorded. Results were analysed using paired t-tests. The results indicated that tapered screws have significantly higher resistance to interference failure (p=0.007) and insertion torque (p<0.001) than non-tapered screws. The improved biomechanical performance of tapered screws demonstrated in this study may translate into superior clinical results, particularly at the tibial attachment of hamstring anterior cruciate ligament reconstruction, and also of hamstring fixation to the medial femoral condyle for patella instability.

An evaluation of interface contact profiles in two low contact bone plates.

Bone plate design has evolved dramatically in recent years. The Dynamic Compression Plate (DCP) has been superseded by bi- and uni-cortical plates that claim a reduced interface contact between the plate and the underlying bone. It is believed that contact reduction ameliorates the localised ischaemia that develops subsequent to plate application. In this study, the interface characteristics of the Limited Contact-Dynamic Compression Plate (LC-DCP) and the Contour Plus (CP) plating systems have been quantitated using Fuji prescale pressure sensitive film interposed between the plate and the bone. Ten-hole plates were applied to the same aspect of either the humeral, radial or ulnar diaphysis of human cadaveric bone in a reproducible manner. The average pressure, force and interface contact area were calculated using Interactive Data Language (IDL) image analysis software. The CP system was consistently lower, in terms of interface contact, than the LC-DCP in each of the specimen locations tested (P<0.0001). The CP system displayed a 'point-contact' configuration along the interface with high pressures recorded at these points, the significance of which is unknown.

Suture characteristics following incubation in synovial fluid or phosphate buffered saline.

Selection of an appropriate suture requires a knowledge of many factors. These include its mechanical characteristics, its durability, the period of mechanical effectiveness and the tissue reactivity to the material. Absorbable suture materials were incubated in synovial fluid or phosphate buffered saline, at 37 degrees C, for periods up to 12 weeks. Mechanical testing was performed to determine the yield strength, percentage elongation and stiffness of each material in response to incubation. Significant differences were observed in response to time of incubation, material size ('0' or '2-0'), incubation medium and material properties (P < 0.001). Based on the results obtained Vicryl and PDS appear ideal for short-term and medium term apposition, respectively. Panacryl has more durable mechanical features and may well be suited to long-term tissue apposition, such as tendon repair or arthroplasty.

Biceps tenodesis: a biomechanical study of fixation methods.

Rupture of the biceps tendon occurs predominantly in the middle-aged and elderly, being predisposed through bicipital tendinitis and rotator cuff lesions. Surgical repair may be an option for those requiring strength in supination. This study compared the initial fixation strength of keyhole tenodesis (n = 7) and interference screw fixation by use of cadaveric specimens. Two interference screws were evaluated (n = 7 x 2): the round-headed cannulated interference screw (RCI) and a bioresorbable screw (Sysorb). All specimens failed at the fixation site but one. This study found that overall there was a significant effect as a result of study group (keyhole vs Sysorb vs RCI, P =.034). The post hoc comparisons revealed that the keyhole was significantly stronger than the RCI screw (P =.033) but not significantly different compared with the Sysorb screw (P =.129). No significant difference was observed between the Sysorb and RCI screws (P =.762). Interference screw fixation failed by tendon slippage at the screw-tendon-bone interface; keyhole fixation failed by tendon splitting and slippage out of the restraining keyhole. Keyhole tenodesis may permit earlier postoperative mobilization when compared with tenodesis by use of interference screw fixation.