Assessment of bias in carbon isotope composition of organic leaf matter due to pre-analysis milling methods.

RATIONALE: Stable isotope analysis of leaf material has many applications including assessment of plant water-use efficiency and palaeoclimatology. To facilitate interpretations of small shifts in the carbon isotope composition (δ13 C) of leaves, accurate and repeatable results are required. Pre-sample homogenisation is essential to ensure a representative sample is analysed, but can also introduce error. METHODS: We investigate how different grinding methods (freezer-milling and ball-milling) affect the carbon content and δ13 C of tree leaves from a wetland in Queensland, Australia, commenting on how increased temperature, sample contamination, sample loss or poor homogenisation may impact results. RESULTS: No alteration of leaf δ13 C is observed due to different milling methods, although there may be a significant increase in %C of samples processed using ball-milling. CONCLUSIONS: We suggest %C variability is possibly due to contamination from abraded plastic vials or insufficient homogenisation during ball-milling, with no significant impact on δ13 C. Overall, we suggest that intermittent ball-milling may be the best solution to reduce costs, preparation time and use of liquid nitrogen, aiming to achieve complete homogenisation using the shortest possible duration of milling.

Carbon isotope discrimination in leaves of the broad-leaved paperbark tree, Melaleuca quinquenervia, as a tool for quantifying past tropical and subtropical rainfall.

Quantitative reconstructions of terrestrial climate are highly sought after but rare, particularly in Australia. Carbon isotope discrimination in plant leaves (Δleaf ) is an established indicator of past hydroclimate because the fractionation of carbon isotopes during photosynthesis is strongly influenced by water stress. Leaves of the evergreen tree Melaleuca quinquenervia have been recovered from the sediments of some perched lakes on North Stradbroke and Fraser Islands, south-east Queensland, eastern Australia. Here, we examine the potential for using M. quinquenervia ∆leaf as a tracer of past rainfall by analysing carbon isotope ratios (δ(13) C) of modern leaves. We firstly assess Δleaf variation at the leaf and stand scale and find no systematic pattern within leaves or between leaves due to their position on the tree. We then examine the relationships between climate and Δleaf for a 11-year time series of leaves collected in a litter tray. M. quinquenervia retains its leaves for 1-4 years; thus, cumulative average climate data are used. There is a significant relationship between annual mean ∆leaf and mean annual rainfall of the hydrological year for 1-4 years (i.e. 365-1460 days) prior to leaf fall (r(2)  = 0.64, P = 0.003, n = 11). This relationship is marginally improved by accounting for the effect of pCO2 on discrimination (r(2)  = 0.67, P = 0.002, n = 11). The correlation between rainfall and Δleaf , and the natural distribution of Melaleuca quinquenervia around wetlands of eastern Australia, Papua New Guinea and New Caledonia offers significant potential to infer past rainfall on a wide range of spatial and temporal scales.

Locked versus nonlocked plate fixation for first metatarsophalangeal arthrodesis: a biomechanical investigation.

BACKGROUND: First metatarsophalangeal (MTP) arthrodesis using dorsal plate fixation is a common procedure for painful conditions of the great toe. Locked plates have become increasingly common for arthrodesis procedures in the foot, including the hallux MTP joint. The biomechanical advantages and disadvantages of these plates are currently unknown. The purpose of this study was to compare locked and nonlocked plates used for first MTP fusion for strength and stiffness. MATERIALS AND METHODS: The first ray of nine matched pairs of fresh-frozen cadaveric feet underwent dissection, preparation with cup-and-cone reamers, and fixation of the MTP joint with a compression screw and either a nonlocked or locked stainless steel dorsal plate. Each specimen was loaded in a cantilever fashion to 90 N at a rate of 3 Hz for a total of 250,000 cycles. The amount of plantar MTP gap was recorded using a calibrated extensometer. Load-to-failure testing was performed for all specimens that endured the entire cyclical loading. Stiffness was calculated from the final load-to-failure test. RESULTS: The locked plate group demonstrated significantly less plantar gapping during fatigue endurance testing from cycle 10,000 through 250,000 (p < .05). Mean stiffness was significantly greater in the locked plate group compared with the nonlocked plate group (p = .02). There was no significant difference in load to failure between the two groups (p = .27). CONCLUSION: Compared with nonlocked plates, locked hallux MTP arthrodesis plates exhibited significantly less plantar gapping after 10,000 cycles of fatigue endurance testing and significantly greater stiffness in load-to-failure testing. CLINICAL RELEVANCE: As the use of locked plate technology is becoming increasingly common for applications in the foot, a thorough understanding of the biomechanical characteristics of these implants may help optimize their indications and clinical use.

Is carpal tunnel release under-utilized in veterans with spinal cord injury?

OBJECTIVE: Carpal tunnel syndrome (CTS) is a common disorder among individuals with spinal cord injury (SCI). Although carpal tunnel release is highly effective, the procedure may be under-utilized in this population. This study attempts to identify if CTS is under-treated in Veterans with SCI. DESIGN: The Veterans Affairs (VA) National Patient Care Database was used for data compilation within fiscal years 2007 and 2008. Using ICD-9-CM diagnoses codes, individuals with SCIs were identified, including those diagnosed with CTS. Current procedural terminology (CPT) codes further showed those who had undergone surgical intervention including open and endoscopic release of the transverse carpal ligament. The VA SCI cohort was compared to the general VA population with regard to demographics, diagnosis, surgical intervention, and treatment location. RESULTS: A total of 19 296 veterans with SCI were identified within the 2-year period. The prevalence of CTS within this cohort was 3.5%, compared to 2.1% in the general VA population. The rate of transverse carpal ligament release was similar between the VA SCI cohort and general population (0.24 and 0.17%, respectively). The majority of surgical treatment (89%) occurred within the VA 'hub-and-spoke' system of SCI care. CONCLUSION: CTS appears to be under-diagnosed and under-treated in veterans with SCI.

Outcomes of Salvage Arthrodesis and Arthroplasty for Failed Osteochondral Allograft Transplantation of the Ankle.

BACKGROUND: Osteochondral allograft (OCA) transplantation is a useful treatment for posttraumatic ankle arthritis in young patients, but failure rates are high and reoperations are not uncommon. The aim of this study was to evaluate the outcomes of failed ankle OCA transplantation converted to ankle arthrodesis (AA) or total ankle arthroplasty (TAA). METHODS: We evaluated 24 patients who underwent salvage procedures (13 AA and 11 TAA) after primary failed ankle OCA transplantation. Reoperations were assessed. Failure of the salvage procedure was defined as an additional surgery that required a revision AA/TAA or amputation. Evaluation among nonfailing ankles included the American Academy of Orthopaedic Surgeons Foot and Ankle Module (AAOS-FAM), pain, and satisfaction. RESULTS: In the salvage AA cohort, 3 patients were classified as failures (2 revision AA and 1 amputation). The 10 nonfailing patients had a mean follow-up of 7.4 years. Eighty-eight percent were satisfied with the procedure, but 63% reported continued problems with their ankle (eg, pain, swelling, stiffness). Mean pain level was 1.9 and AAOS-FAM core score was 83±13. In the salvage TAA cohort, 2 patients were classified as failures (both revision TAA). The 9 nonfailing patients had a mean follow-up of 3.8 years. Fifty percent were satisfied with the procedure, but 40% reported continued problems with their ankle. The mean pain level was 1.3, and the median AAOS-FAM core score was 82±26. CONCLUSION: Revision and reoperation rates for salvage procedures following failed OCA transplantation of the ankle are higher compared to published data for primary AA and TAA procedures. However, we believe OCA transplantation can serve as an interim procedure for younger patients with advanced ankle joint disease who may not be ideal candidates for primary AA or TAA at the time of initial presentation. LEVEL OF EVIDENCE: Level IV, case series.

Offering integrated medical equipment management in an application service provider model.

With the advancement of medical technology and thus the complexity of the equipment under their care, clinical engineering departments (CEDs) must continue to make use of computerized tools in the management of departmental activities. Authors of this paper designed, installed, and implemented an application service provider (ASP) model at the laboratory level to offer value added management tools in an online format to CEDs. The project, designed to investigate how to help meet demands across multiple healthcare organizations and provide a means of access for organizations that otherwise might not be able to take advantage of the benefits of those tools, has been well received. Ten hospitals have requested the service, and five of those are ready to proceed with the implementation of the ASP. With the proposed centralized system architecture, the model has shown promise in reducing network infrastructure labor and equipment costs, benchmarking of equipment performance indicators, and developing avenues for proper and timely problem reporting. The following is a detailed description of the design process from conception to implementation of the five main software modules and supporting system architecture.

Arthroscopic Correlates of Subtle Syndesmotic Injury.

BACKGROUND: Arthroscopic criteria for identifying syndesmotic disruption have been variable and subjective. We aimed to quantify syndesmotic disruption arthroscopically using a standardized measurement device. METHODS: Ten cadaveric lower extremity specimens were tested in intact state and after serial sectioning of the syndesmotic structures (anterior inferior tibiofibular ligament [AiTFL], interosseous ligament [IOL], posterior inferior tibiofibular ligament [PiTFL], deltoid). Diagnostic ankle arthroscopy was performed after each sectioning. Manual external rotational stress was applied across the tibiofibular joint. Custom-manufactured spherical balls of increasing diameter mounted on the end of an arthroscopic probe were inserted into the tibiofibular space to determine the degree of diastasis of the tibiofibular joint under each condition. RESULTS: A ball 3 mm in diameter reliably indicated a high likelihood of combined disruption of the AiTFL and IOL. Disruption of the AiTFL alone could not be reliably distinguished from the intact state. CONCLUSION: Use of a spherical probe placed into the tibiofibular space during manual external rotation of the ankle provided an objective measure of syndesmotic instability. Passage of a 2.5-mm probe indicated some disruption of the syndesmosis, but the test had poor negative predictive value. Passage of a 3.0-mm spherical probe indicated very high likelihood of disruption of both the AiTFL and the IOL. CLINICAL RELEVANCE: The findings challenge the previously used but unsupported standard of a 2-mm diastasis of the tibiofibular articulation for diagnosis of subtle syndesmotic instability.

Pathological role of fibroblast-like synoviocytes in charcot neuroarthropathy.

This study was designed to characterize the synovium in the joints of Charcot neuroarthropathy (CNA) and investigate the potential role of fibroblast-like synoviocytes (FLS) in the pathology of CNA. Synovial samples were collected from CNA patients (n = 7) and non-CNA patients (n = 7), for control, during orthopaedic procedures and used for histology and isolation of FLS. Histological characterization of synovium included innervation and FLS localization. The isolated FLS from the CNA and non-CNA synovium were cultured, with or without tumor necrosis factor-α (TNF-α), for evaluation of invasiveness, gene expression, and cartilage degradation. Vasoactive intestinal peptide (VIP), a neuropeptide, was supplemented into the co-cultures of FLS and cartilage explants. Compared with the non-CNA synovium, CNA synovium was highly inflammatory, with reduced innervation and intense expression of cadherin-11. The FLS isolated from CNA synovium, particularly when activated with TNF-α, were more invasive, increased the expression of ADAMTS4, IL-6, and RANKL, and depleted proteoglycans from cartilage explants when they were co-cultured. Addition of VIP into the culture medium neutralized the catabolic effect of the CNA FLS on cartilage explants. In conclusion, FLS plays an important role in the pathology of CNA. Therapies targeting synovium and FLS may prevent or treat the joint destruction in CNA.

Plating of metacarpal fractures with locked or nonlocked screws, a biomechanical study: how many cortices are really necessary?

BACKGROUND: Dorsal plate and screw fixation is a popular choice for metacarpal stabilization. The balance between construct stability and soft tissue dissection remains a surgical dilemma. Historically, six cortices of bone fixation on either side of a fracture were deemed necessary. This study aims to elucidate whether four cortices of locked fixation on either side of the fracture is equivalent to the current gold standard of six cortices of nonlocked fixation on either side of the fracture. If so, less dissection to insert shorter plates with fewer screws could be used to stably fix these fractures. METHODS: With biomechanical testing-grade composite Sawbones, a comminuted metacarpal fracture model was used to test two fixation constructs consisting of a standard dorsal plate and either six bicortical nonlocking screws (three screws per segment) or four bicortical locking screws (two screws per segment). Thirty specimens were tested to failure in cantilever bending and torsion. RESULTS: There was statistical equivalence between the locking and nonlocking constructs in cantilever bending stiffness, torsional stiffness, maximum bending load, and maximum torque. CONCLUSION: The tested metacarpal fracture model had equivalent biomechanical properties when fixed with a standard dorsal plate and either six bicortical nonlocking screws or four bicortical locking screws. By utilizing fewer cortices of fixation, there will be less dissection and less soft tissue stripping during fixation of metacarpal fractures. This will also be of benefit in very proximal or distal fractures as multiple cortices of fixation are often difficult to obtain during stabilization of these challenging fractures.

Platelet-rich plasma and the upper extremity.

Platelet-rich plasma (PRP) is a fraction of whole blood containing powerful growth factors and cytokines. Preclinical studies suggest PRP may be useful for tendon repair or regeneration. Clinical investigations have focused on the treatment of chronic lateral epicondylar tendinopathy and rotator cuff pathology. Multiple controlled studies support the use of PRP for chronic tennis elbow. Rotator cuff studies, however, have produced conflicting results based on PRP formulation, surgical technique, and size of tendon tear. This article explores the scientific rational for using PRP, its various formulations, and the emerging clinical data. Future potential applications are also explored.

Foot and ankle questions on the orthopaedic in-training examination: analysis of content, reference, and performance.

The purpose of this study was to provide a comprehensive analysis of the Orthopaedic In-Training Examination's (OITE's) questions, question sources, and resident performance over the course of residency training.The authors analyzed all OITE questions pertaining to foot and ankle surgery between 2006 and 2010. Recorded data included the topic and area tested, imaging modality used, tested treatment method, taxonomic classification, cited references, and resident performance scores. Foot- and ankle-related questions made up 13.9% (186/1341) of the OITE questions. Thirteen general topic areas were identified, with the most common being foot and ankle trauma, the pediatric foot, and foot and ankle deformity. Imaging modalities were tested in approximately half of the questions. Knowledge of treatment modalities was required in 58.1% (108/186) of the questions. Recall-type questions were the most common. Trends existed in the recommended references, with 2 journals and 1 textbook being commonly and consistently cited: Foot and Ankle International, The Journal of Bone and Joint Surgery American Volume, and Surgery of the Foot and Ankle, respectively. Resident performance scores increased with each successive level of training.An understanding of the topics and resources used for OITE foot and ankle questions is an important aid in creating or improving residency programs' foot and ankle education curricula. With knowledge of question content, source, and resident performance, education can be optimized toward efficient learning and improved scores on this section of the examination.

Building a new predictor for multiple linear regression technique-based corrective maintenance turnaround time.

OBJECTIVES: This research's main goals were to build a predictor for a turnaround time (TAT) indicator for estimating its values and use a numerical clustering technique for finding possible causes of undesirable TAT values. MATERIALS AND METHODS: The following stages were used: domain understanding, data characterisation and sample reduction and insight characterisation. Building the TAT indicator multiple linear regression predictor and clustering techniques were used for improving corrective maintenance task efficiency in a clinical engineering department (CED). The indicator being studied was turnaround time (TAT). RESULTS: Multiple linear regression was used for building a predictive TAT value model. The variables contributing to such model were clinical engineering department response time (CE(rt), 0.415 positive coefficient), stock service response time (Stock(rt), 0.734 positive coefficient), priority level (0.21 positive coefficient) and service time (0.06 positive coefficient). The regression process showed heavy reliance on Stock(rt), CE(rt) and priority, in that order. Clustering techniques revealed the main causes of high TAT values. CONCLUSIONS: This examination has provided a means for analysing current technical service quality and effectiveness. In doing so, it has demonstrated a process for identifying areas and methods of improvement and a model against which to analyse these methods' effectiveness.

Magnetic resonance imaging of the ankle at 3.0 Tesla and 1.5 Tesla in human cadaver specimens with artificially created lesions of cartilage and ligaments.

PURPOSE: To compare magnetic resonance imaging of the ankle joint at 1.5 Tesla (T) and 3.0 T in the assessment of cartilage and ligament pathology in fresh human cadaver specimens. MATERIALS AND METHODS: The study was performed in line with institutional and legislative requirements; all donors had dedicated their body for educational and research purposes before death. Thirteen fresh human cadaver ankle joints were imaged at 1.5 T and 3.0 T using an optimized clinical ankle protocol consisting of T1-weighted (T1-w), fat-saturated (fs) T2-w, and short tau inversion recovery fast spinecho (FSE) sequences. For dedicated cartilage imaging, fs-intermediate (IM)-w FSE, fs-spoiled gradient echo, and balanced free precession steady state sequences were acquired. Artificial cartilage and ligament lesions were created in 6 and 5 specimens, respectively. MR imaging was repeated in those ankles. Four radiologists independently assessed pathology in all image datasets. Macroscopic findings after dissection served as a reference standard. RESULTS: Sensitivities and ROC-values were higher at 3.0 T for detecting cartilage pathology (sensitivity up to 0.71 at 3.0 T vs. 0.49 at 1.5 T; AZ up to 0.88 vs. 0.74; both differences P < 0.05) and highest for the fs-IM FSE sequence at 3.0 T. Average sensitivity for detecting ligament pathology was higher at 3.0 T (0.69 vs. 0.50; P < 0.05). Specificity was high among all protocols and both field strengths for assessing ligament and cartilage pathology (>0.95). CONCLUSION: Compared with 1.5-T imaging, the 3.0-T imaging of the ankle joint at improved diagnostic performance in assessing cartilage significantly and there was a higher sensitivity for assessing ligamentous pathology.

MR imaging of the ankle at 3 Tesla and 1.5 Tesla: protocol optimization and application to cartilage, ligament and tendon pathology in cadaver specimens.

The objective of this study was to optimize ankle joint MR imaging in volunteers at 1.5 Tesla (T) and 3.0 T, and to compare these optimized sequences concerning image quality and performance in assessing cartilage, ligament and tendon pathology in fresh human cadaver specimens. Initially our clinical ankle protocol consisting of T1-weighted (-w), fat-saturated (fs) T2-w, and short tau inversion-recovery fast spinecho (FSE) sequences was optimized at 1.5 T and 3.0 T by two radiologists. For dedicated cartilage imaging, fs-intermediate (IM)-w FSE, fs spoiled gradient echo, and balanced free-precession steady-state sequences were optimized. Using the optimized sequences, thirteen cadaver ankle joints were imaged. Four radiologists independently assessed these images concerning image quality and pathology. All radiologists consistently rated image quality higher at 3.0 T (all sequences p<0.05). For detecting cartilage pathology, diagnostic performance was significantly higher at 3.0 T (ROC-values up to 0.93 vs. 0.77; p<0.05); the fs-IM FSE sequence showed highest values among the different sequences. Average sensitivity for detecting tendon pathology was 63% at 3.0 T vs. 41% at 1.5 T and was significantly higher at 3.0 T for 2 out of 4 radiologists (p<0.05). Compared to 1.5 T, imaging of the ankle joint at 3.0 T significantly improved image quality and diagnostic performance in assessing cartilage pathology.

EVALUACIÓN DE LAS SOLICITUDES DE MANTENIMIENTO CORRECTIVO USANDO TÉCNICAS DE AGRUPAMIENTO Y REGLAS DE ASOCIACIÓN

En este trabajo se exponen los resultados obtenidos de la aplicación de técnicas de descubrimiento de asociaciones y de agrupamiento para resolver el problema de la baja eficiencia presentado en un servicio de esterilización de un hospital en estudio. El objetivo fue detectar y discriminar las causas fundamentales que contribuyeron al surgimiento del problema presentado para luego solucionarlo. Para realizar esta investigación se recabó la información contenida en las solicitudes de servicio de mantenimiento correctivo y las órdenes de trabajos durante el período 2002-2004. Primeramente se segmentó la información contenida en el indicador en estudio: razón de las solicitudes de servicio de mantenimiento correctivo vs. cantidad de equipos por tipos de equipos, por servicios, por fabricante (OEM, del inglés Original Equipment Manufacturer) y por modelos. Luego con las técnicas de descubrimiento de asociaciones aplicadas se encontraron las causas fundamentales por las cuales se solicitaban los reportes de servicios. Éstas fueron: falta de entrenamiento en usuarios, fallos intrínsecos en los dispositivos médicos y malas políticas en el establecimiento de la frecuencia del mantenimiento programado. Las técnicas de agrupamientos pudieron discriminar las causas fundamentales por las cuales los dispositivos médicos del servicio de esterilización fallaban. Éstas fueron debido a fallos en el sistema de suministro de vapor y agua que alimenta las unidades de esterilización (en un 75% de los casos). Se tomaron medidas correctoras durante el período 2005-2006, que contribuyeron a que el indicador bajo estudio disminuyera de 6,4 a 0,4 unidades.

In this research association discovering and clustering techniques for the resolution of the low efficiency problem in the sterilization service in a hospital under study were used. The aim was to find and to discriminate the main causes of the problem under study and then to apply corrective solutions. To conduct this research the information contained in corrective maintenance work orders and service requests in the period under study (2002-2004) was collected. First a segmentation of the information was carried out using the indicator: corrective service request versus number of medical devices. The levels of the information segmentation were: equipment types, services or cost centre, original equipment manufacturer and models. Then the association discovery technique was used. It revealed that the main causes of low efficiency in sterilization service were: users' training (errors in operation procedures), intrinsic failures in medical devices, and bad scheduled maintenance policies. Clustering technique uncovered the main causes of failures: malfunctioning of the power supply system (steam and water, in 75% of all cases). With the evidence obtained corrective actions were taken. The service requests dropped dramatically from 6.4 to 0.4 during the period 2005-2006.