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  • Development of a Prediction Model for Stress Fracture During an Intensive Physical Training Program: The Royal Marines Commandos.

    24 October 2018

    BACKGROUND: Stress fractures (SFs) are one of the more severe overuse injuries in military training, and therefore, knowledge of potential risk factors is needed to assist in developing mitigating strategies. PURPOSE: To develop a prediction model for risk of SF in Royal Marines (RM) recruits during an arduous military training program. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: RM recruits (N = 1082; age range, 16-33 years) who enrolled between September 2009 and July 2010 were prospectively followed through the 32-week RM training program. SF diagnosis was confirmed from a positive radiograph or magnetic resonance imaging scan. Potential risk factors assessed at week 1 included recruit characteristics, anthropometric assessment, dietary supplement use, lifestyle habits, fitness assessment, blood samples, 25(OH)D, bone strength as measured by heel broadband ultrasound attention, history of physical activity, and previous and current food intake. A logistic least absolute shrinkage and selection operator (LASSO) regression with 10-fold cross-validation was used to select potential predictors among 47 candidate variables. Model performance was assessed using measures of discrimination (c-index) and calibration. Bootstrapping was used for internal validation of the developed model and to quantify optimism. RESULTS: A total of 86 (8%) volunteer recruits presented at least 1 SF during training. Twelve variables were identified as the most important risk factors of SF. Variables strongly associated with SF were age, body weight, pretraining weightbearing exercise, pretraining cycling, and childhood intake of milk and milk products. The c-index for the prediction model, which represents the model performance in future volunteers, was 0.73 (optimism-corrected c-index, 0.68). Although 25(OH)D and VO2max had only a borderline statistically significant association with SF, the inclusion of these factors improved the performance of the model. CONCLUSION: These findings will assist in identifying recruits at greater risk of SF during training and will support interventions to mitigate this injury risk. However, external validation of the model is still required.

  • [Recommendations of EULAR on treatment of gonarthrosis. Report of a committee of the "Standing Committee for International Clinical Studies Including Therapeutic Trials (ESCIST)"].

    24 October 2018

    BACKGROUND: Osteoarthritis (OA) is the most common joint disease encountered throughout Europe. A task force for the EULAR standing committee for clinical trials met in 1998 to determine the methodological and logistical approach required for the development of evidence-based guidelines for treatment of knee OA. The guidelines were restricted to cover all currently available therapies for knee OA diagnosed either clinically and/or radiographically affecting any compartment of the knee. METHODS: The first stage was the selection of treatment modalities to be considered. The second stage comprised a search of the electronic databases Medline and Embase using a combination of subject headings and key words. All European language publications in the form of systematic reviews, meta-analyses, randomized-controlled trials, controlled trials and observational studies were included. During stage three all of the relevant studies were quality scored. The summary statistics for validated outcome measures, when available, were recorded and where practical the numbers needed to treat (NNT) and the effect size (ES) for each therapy was calculated. The fourth stage involved determination of key clinical propositions by expert consensus employing a Delphi approach. The final stage involved ranking of these propositions according to the available evidence. A second set of propositions relating to a future research agenda was determined by expert consensus using a Delphi approach. RESULTS: Over 2400 English language publications and 400 non-English language publications were identified. Seven hundred and forty four studies presented outcome data of the effects of specific treatments on knee OA. Quantitative analysis of treatment effect was possible in only 61 studies. Recommendations for the management of knee OA based on currently available data and expert opinion are presented. Proposals for a future research agenda are highlighted. CONCLUSIONS: These are the first clinical guidelines on knee OA to combine an evidence-based approach and a consensus approach across a wide range of treatment modalities. It is apparent that only certain clinical propositions are supported by substantial research-based evidence, while others are not. There is thus an urgent need for future well designed trials to address key clinical questions.

  • The inferomedial femoral neck is compromised by age but not disease: Fracture toughness and the multifactorial mechanisms comprising reference point microindentation.

    24 October 2018

    The influence of ageing on the fracture mechanics of cortical bone tissue is well documented, though little is known about if and how related material properties are further affected in two of the most prominent musculoskeletal diseases, osteoporosis and osteoarthritis (OA). The femoral neck, in close proximity to the most pertinent osteoporotic fracture site and near the hip joint affected by osteoarthritis, is a site of particular interest for investigation. We have recently shown that Reference Point micro-Indentation (RPI) detects differences between cortical bone from the femoral neck of healthy, osteoporotic fractured and osteoarthritic hip replacement patients. RPI is a new technique with potential for in vivo bone quality assessment. However, interpretation of RPI results is limited because the specific changes in bone properties with pathology are not well understood and, further, because it is not conclusive what properties are being assessed by RPI. Here, we investigate whether the differences previously detected between healthy and diseased cortical bone from the femoral neck might reflect changes in fracture toughness. Together with this, we investigate which additional properties are reflected in RPI measures. RPI (using the Biodent device) and fracture toughness tests were conducted on samples from the inferomedial neck of bone resected from donors with: OA (41 samples from 15 donors), osteoporosis (48 samples from 14 donors) and non age-matched cadaveric controls (37 samples from 10 donoros) with no history of bone disease. Further, a subset of indented samples were imaged using micro-computed tomography (3 osteoporotic and 4 control samples each from different donors) as well as fluorescence microscopy in combination with serial sectioning after basic fuchsin staining (7 osteoporotic and 5 control samples from 5 osteoporotic and 5 control donors). In this study, the bulk indentation and fracture resistance properties of the inferomedial femoral neck in osteoporotic fracture, severe OA and control bone were comparable (p > 0.05 for fracture properties and <10% difference for indentation) but fracture toughness reduced with advancing age (7.0% per decade, r = -0.36, p = 0.029). Further, RPI properties (in particular, the indentation distance increase, IDI) showed partial correlation with fracture toughness (r = -0.40, p = 0.023) or derived elastic modulus (r = -0.40, p = 0.023). Multimodal indent imaging revealed evidence of toughening mechanisms (i.e. crack deflection, bridging and microcracking), elastoplastic response (in terms of the non-conical imprint shape and presence of pile-up) and correlation of RPI with damage extent (up to r = 0.79, p = 0.034) and indent size (up to r = 0.82, p < 0.001). Therefore, crack resistance, deformation resistance and, additionally, micro-structure (porosity: r = 0.93, p = 0.002 as well as pore proximity: r = -0.55, p = 0.027 for correlation with IDI) are all contributory to RPI. Consequently, it becomes clear that RPI measures represent a multitude of properties, various aspects of bone quality, but are not necessarily strongly correlated to a single mechanical property. In addition, osteoporosis or osteoarthritis do not seem to further influence fracture toughness of the inferomedial femoral neck beyond natural ageing. Since bone is highly heterogeneous, whether this finding can be extended to the whole femoral neck or whether it also holds true for other femoral neck quadrants or other material properties remains to be shown.