Symbiont plasticity as a driver of plant success.

We discuss which plant species are likely to become winners, that is achieve the highest global abundance, in changing landscapes, and whether plant-associated microbes play a determining role. Reduction and fragmentation of natural habitats in historic landscapes have led to the emergence of patchy, hybrid landscapes, and novel landscapes where anthropogenic ecosystems prevail. In patchy landscapes, species with broad niches are favoured. Plasticity in the degree of association with symbiotic microbes may contribute to broader plant niches and optimization of symbiosis costs and benefits, by downregulating symbiosis when it is unnecessary and upregulating it when it is beneficial. Plasticity can also be expressed as the switch from one type of mutualism to another, for example from nutritive to defensive mutualism with increasing soil fertility and the associated increase in parasite load. Upon dispersal, wide mutualistic partner receptivity is another facet of symbiont plasticity that becomes beneficial, because plants are not limited by the availability of specialist partners when arriving at new locations. Thus, under conditions of global change, symbiont plasticity allows plants to optimize the activity of mutualistic relationships, potentially allowing them to become winners by maximizing geographic occupancy and local abundance.

Niche types and community assembly.

Studies of niche differentiation and biodiversity often focus on a few niche dimensions due to the methodological challenge of describing hyperdimensional niche space. However, this may limit our understanding of community assembly processes. We used the full spectrum of realized niche types to study arbuscular mycorrhizal fungal communities: distinguishing abiotic and biotic, and condition and resource, axes. Estimates of differentiation in relation to different niche types were only moderately correlated. However, coexisting taxon niches were consistently less differentiated than expected, based on a regional null model, indicating the importance of habitat filtering at that scale. Nonetheless, resource niches were relatively more differentiated than condition niches, which is consistent with the effect of a resource niche-based coexistence mechanism. Considering niche types, and in particular distinguishing resource and condition niches, provides a more complete understanding of community assembly, compared with studying individual niche axes or the full niche.

Soil community composition in dynamic stages of semi-natural calcareous grassland.

European dry thin-soil calcareous grasslands (alvars) are species-rich semi-natural habitats. Cessation of traditional management, such as mowing and grazing, leads to shrub and tree encroachment and the local extinction of characteristic alvar species. While soil microbes are known to play a critical role in driving vegetation and ecosystem dynamics, more information is needed about their composition and function in grasslands of different dynamic stages. Here we assess the composition of soil fungal, prokaryotic, and plant communities using soil environmental DNA from restored alvar grasslands in Estonia. The study areas included grasslands that had experienced different degrees of woody encroachment prior to restoration (woody plant removal and grazing), as well as unmanaged open grasslands. We found that, in general, different taxonomic groups exhibited correlated patterns of between-community variation. Previous forest sites, which had prior to restoration experienced a high degree of woody encroachment by ectomycorrhizal Scots pine, were compositionally most distinct from managed open grasslands, which had little woody vegetation even prior to restoration. The functional structure of plant and fungal communities varied in ways that were consistent with the representation of mycorrhizal types in the ecosystems prior to restoration. Compositional differences between managed and unmanaged open grasslands reflecting the implementation of grazing without further management interventions were clearer among fungal, and to an extent prokaryotic, communities than among plant communities. While previous studies have shown that during woody encroachment of alvar grassland, plant communities change first and fungal communities follow, our DNA-based results suggest that microbial communities reacted faster than plant communities during the restoration of grazing management in alvar grassland. We conclude that while the plant community responds faster to cessation of management, the fungal community responds faster to restoration of management. This may indicate hysteresis, where the eventual pathway back to the original state (grazed ecosystem) differs from the pathway taken towards the alternative state (abandoned semi-natural grassland ecosystem).

GlobalAMFungi: a global database of arbuscular mycorrhizal fungal occurrences from high-throughput sequencing metabarcoding studies.

Arbuscular mycorrhizal (AM) fungi are crucial mutualistic symbionts of the majority of plant species, with essential roles in plant nutrient uptake and stress mitigation. The importance of AM fungi in ecosystems contrasts with our limited understanding of the patterns of AM fungal biogeography and the environmental factors that drive those patterns. This article presents a release of a newly developed global AM fungal dataset (GlobalAMFungi database, https://globalamfungi.com) that aims to reduce this knowledge gap. It contains almost 50 million observations of Glomeromycotinian AM fungal amplicon DNA sequences across almost 8500 samples with geographical locations and additional metadata obtained from 100 original studies. The GlobalAMFungi database is built on sequencing data originating from AM fungal taxon barcoding regions in: i) the small subunit rRNA (SSU) gene; ii) the internal transcribed spacer 2 (ITS2) region; and iii) the large subunit rRNA (LSU) gene. The GlobalAMFungi database is an open source and open access initiative that compiles the most comprehensive atlas of AM fungal distribution. It is designed as a permanent effort that will be continuously updated by its creators and through the collaboration of the scientific community. This study also documented applicability of the dataset to better understand ecology of AM fungal taxa.

Incidence and risk factors for non-union of the superior ramus osteotomy when hip dysplasia is treated with periacetabular osteotomy.

Periacetabular osteotomy (PAO) is a well-established surgical treatment for hip dysplasia. Few studies report risk factors for the development of superior ramus osteotomy non-union. The purpose of this investigation was to document the incidence and risk factors for this complication. We identified 316 consecutive hips that underwent PAO for symptomatic acetabular dysplasia with a minimum 1-year radiographic follow-up. We developed and validated a technique to measure the superior ramus osteotomy location on anterior-posterior (AP) pelvis radiographs and computed tomography. Logistic regression with generalized estimating equations was used to evaluate the relationships between odds of non-union and potential demographic and radiographic predictor variables in univariate and multivariate analyses. Twenty-nine (9.2%) hips developed superior ramus non-union. Age {median [interquartile range (IQR)] 23 years (18-35) healed versus 35 years (26-40) non-united, P = 0.001}, pre-operative lateral center-edge angle (LCEA) [16° (11-20) healed versus 10° (6-13) non-united, P < 0.001] and the distance from the superior ramus osteotomy to the ilioishial line [15.8 mm (13.2-18.7) healed versus 18.1 mm (16.2-20.5) non-united, P < 0.001] varied significantly between groups. Using multivariate analysis, moderate-to-severe dysplasia [LCEA < 15°, odds ratio (OR) 5.95, standard error (SE) 3.32, 95% confidence interval (CI) 1.99-17.79, P = 0.001], increased age (5-year increase, OR 1.29, SE 3.32, 95% CI 1.105-1.60, P-value = 0.018) and distance from the ilioishial line (3-mm increase, OR 1.67, SE 0.22, 95% CI 1.29-2.18, P < 0.001) were at increased risk of developing non-union. Superior ramus osteotomy non-union is common after PAO. Older age, moderate-to-severe dysplasia, and more medial osteotomy location were independent risk factors for non-union. Consideration should be made in high-risk patients for a more lateral superior ramus osteotomy and adjuvant medical and surgical interventions.

Environmental modulation of plant mycorrhizal traits in the global flora.

Mycorrhizal symbioses are known to strongly influence plant performance, structure plant communities and shape ecosystem dynamics. Plant mycorrhizal traits, such as those characterising mycorrhizal type (arbuscular (AM), ecto-, ericoid or orchid mycorrhiza) and status (obligately (OM), facultatively (FM) or non-mycorrhizal) offer valuable insight into plant belowground functionality. Here, we compile available plant mycorrhizal trait information and global occurrence data ( ∼ 100 million records) for 11,770 vascular plant species. Using a plant phylogenetic mega-tree and high-resolution climatic and edaphic data layers, we assess phylogenetic and environmental correlates of plant mycorrhizal traits. We find that plant mycorrhizal type is more phylogenetically conserved than plant mycorrhizal status, while environmental variables (both climatic and edaphic; notably soil texture) explain more variation in mycorrhizal status, especially FM. The previously underestimated role of environmental conditions has far-reaching implications for our understanding of ecosystem functioning under changing climatic and soil conditions.

Plant-symbiotic fungal diversity tracks variation in vegetation and the abiotic environment along an extended elevational gradient in the Himalayas.

Arbuscular mycorrhizal (AM) fungi can benefit plants under environmental stress, and influence plant adaptation to warmer climates. However, very little is known about the ecology of these fungi in alpine environments. We sampled plant roots along a large fraction (1941-6150 m asl (above sea level)) of the longest terrestrial elevational gradient on Earth and used DNA metabarcoding to identify AM fungi. We hypothesized that AM fungal alpha and beta diversity decreases with increasing elevation, and that different vegetation types comprise dissimilar communities, with cultured (putatively ruderal) taxa increasingly represented at high elevations. We found that the alpha diversity of AM fungal communities declined linearly with elevation, whereas within-site taxon turnover (beta diversity) was unimodally related to elevation. The composition of AM fungal communities differed between vegetation types and was influenced by elevation, mean annual temperature, and precipitation. In general, Glomeraceae taxa dominated at all elevations and vegetation types; however, higher elevations were associated with increased presence of Acaulosporaceae, Ambisporaceae, and Claroideoglomeraceae. Contrary to our expectation, the proportion of cultured AM fungal taxa in communities decreased with elevation. These results suggest that, in this system, climate-induced shifts in habitat conditions may facilitate more diverse AM fungal communities at higher elevations but could also favour ruderal taxa.

Early Versus Delayed Surgery for Midshaft Clavicle Fractures: A Systematic Review.

Background: Orthopaedic surgeons debate the timing of and necessity for surgical intervention when treating displaced midshaft clavicle fractures (MCFs). This systematic review evaluates the available literature regarding functional outcomes, complication rates, nonunion, and reoperation rates between patients undergoing early versus delayed surgical management of MCFs. Methods: Search strategies were applied in PubMed (Medline), CINAHL (EBSCO), Embase (Elsevier), Sport Discus (EBSCO), and Cochrane Central Register of Controlled Trials (Wiley). Following an initial screening and full-text review, demographic and study outcome data was extracted for comparison between the early fixation and delayed fixation studies. Results: Twenty-one studies were identified for inclusion. This resulted in 1158 patients in the early group and 44 in the delayed. Demographics were similar between groups except for a higher percentage of males in the early group (81.6% vs. 61.4%) and longer time to surgery in the delayed group (4.6 days vs. 14.5 months). Disability of the arm, shoulder, and hand scores (3.6 vs. 13.0) and Constant-Murley scores (94.0 vs. 86.0) were better in the early group. Percentages of initial surgeries resulting in complication (33.8% vs. 63.6%), nonunion (1.2% vs. 11.4%), and nonroutine reoperation (15.8% vs. 34.1%) were higher in the delayed group. Conclusion: Outcomes of nonunion, reoperation, complications, DASH scores, and CM scores favor early surgery over delayed surgery for MCFs. However, given the small cohort of delayed patients who still achieved moderate outcomes, we recommend a shared decision-making style for treatment recommendations regarding individual patients with MCFs. Level of Evidence: II.

Food Insecurity Is Common in the Orthopedic Trauma Population at a Rural Academic Trauma Center.

Background: Food insecurity is an increasingly recognized public health issue. Identifying risk factors for food insecurity would support public health initiatives to provide targeted nutrition interventions to high-risk individuals. Food insecurity has not been investigated in the orthopedic trauma population. Methods: From April 27, 2021 to June 23, 2021, we surveyed patients within six months of operative pelvic and/or extremity fracture fixation at a single institution. Food insecurity was assessed using the validated United States Department of Agriculture Household Food Insecurity questionnaire generating a food security score of 0 to 10. Patients with a food security score ≥ 3 were classified as Food Insecure (FI) and patients with a food security score < 3 were classified as Food Secure (FS). Patients also completed surveys for demographic information and food consumption. Differences between FI and FS for continuous and categorical variables were evaluated using the Wilcoxon sum rank test and Fisher's exact test, respectively. Spearman's correlation was used to describe the relationship between food security score and participant characteristics. Logistic regression was used to determine the relationship between patient demographics and odds of FI. Results: We enrolled 158 patients (48% female) with a mean age of 45.5 ± 20.3 years. Twenty-one patients (13.3%) screened positive for food insecurity (High security: n=124, 78.5%; Marginal security: n=13, 8.2%; Low security: n=12, 7.6%; Very Low security: n=9, 5.7%). Those with a household income level of ≤ $15,000 were 5.7 times more likely to be FI (95% CI 1.8-18.1). Widowed/single/divorced patients were 10.2 times more likely to be FI (95% CI 2.3-45.6). Median time to the nearest full-service grocery store was significantly longer for FI patients (t=10 minutes) than for FS patients (t=7 minutes, p=0.0202). Age (r= -0.08, p=0.327) and hours working (r= -0.10, p=0.429) demonstrated weak to no correlation with food security score. Conclusion: Food insecurity is common in the orthopedic trauma population at our rural academic trauma center. Those with lower household income and those living alone are more likely to be FI. Multicenter studies are warranted to evaluate the incidence and risk factors for food insecurity in a more diverse trauma population and to better understand its impact on patient outcomes. Level of Evidence: III.

Patient attitudes to nebulised antibiotics in the treatment of bronchiectasis: a mixed-methods study.

Background: Regular daily nebulised antibiotics are widely used in managing bronchiectasis. This patient population typically has severe bronchiectasis requiring multiple other medications. Given that little is known about patients' views and preferences for such therapies, this was the focus of our study. Methods: To explore patient lived-experience using nebulised antibiotics, focus groups and semi-structured interviews were conducted with patients and carers; these were audio-recorded and transcribed to enable thematic analysis. QSR NVivo software facilitated data management. The themes developed from the qualitative data analysis were then used to co-design a questionnaire to capture attitudes and preferences towards nebulised therapy. Questionnaires were completed by patients and statistical analysis was performed. Ethical approval was obtained (13/WS/0036). Results: The study's focus groups comprised 13 patients and carers, and 101 patients completed the questionnaire. Patients described nebulised therapy as an imposition on their daily routine, in turn affecting reported rates of adherence. Results demonstrated that 10% of all patients using nebulised antibiotics found these hard/very hard to administer. Further, 53% of participants strongly agreed/agreed that they would prefer an antibiotic delivered by an inhaler over a nebuliser, if it were as effective at preventing exacerbations. Notably, only 10% of participants wished to remain on nebulised therapy. Conclusions: Inhaled antibiotics delivered via dry powder devices were deemed quicker and easier to use by patients. Providing they were at least as effective as current nebulised treatments, patients deemed inhaled antibiotics to be a preferable treatment option.

Psychosocial care in DHB-based stroke services in Aotearoa: a survey of current practice.

AIM: Stroke has significant psychosocial impacts which contribute to burden for the person with stroke and affect stroke outcomes. The Psychosocial Working Group of the National Stroke Network (NSN) sought to survey current practices for assessing and supporting psychosocial needs within district health board (DHB) based stroke services to inform national service delivery initiatives. METHODS: The survey was conducted in 2021. It was distributed to senior clinicians in all DHBs via the NSN. RESULTS: Thirty-seven responses were received from stroke services, representing 90% of DHBs. Sixty-three percent of services reported some process for screening for psychosocial needs. Of these, only 11% used validated screens. Variability in the type of psychosocial support was evident. Seven percent of services had routine access to psychology, while 53% could access psychology on referral. There was limited evidence of specific screening and support processes for Maori, Pacific peoples, or those with communication impairments. Respondents identified training and resources needs to enable better psychosocial care. CONCLUSION: Stroke services are not consistently meeting national guidelines which require all services have a process for screening for psychosocial needs. This survey has informed a work programme to support psychosocial care practices in stroke services in Aotearoa New Zealand.

Metabarcoding of soil environmental DNA to estimate plant diversity globally.

Introduction: Traditional approaches to collecting large-scale biodiversity data pose huge logistical and technical challenges. We aimed to assess how a comparatively simple method based on sequencing environmental DNA (eDNA) characterises global variation in plant diversity and community composition compared with data derived from traditional plant inventory methods. Methods: We sequenced a short fragment (P6 loop) of the chloroplast trnL intron from from 325 globally distributed soil samples and compared estimates of diversity and composition with those derived from traditional sources based on empirical (GBIF) or extrapolated plant distribution and diversity data. Results: Large-scale plant diversity and community composition patterns revealed by sequencing eDNA were broadly in accordance with those derived from traditional sources. The success of the eDNA taxonomy assignment, and the overlap of taxon lists between eDNA and GBIF, was greatest at moderate to high latitudes of the northern hemisphere. On average, around half (mean: 51.5% SD 17.6) of local GBIF records were represented in eDNA databases at the species level, depending on the geographic region. Discussion: eDNA trnL gene sequencing data accurately represent global patterns in plant diversity and composition and thus can provide a basis for large-scale vegetation studies. Important experimental considerations for plant eDNA studies include using a sampling volume and design to maximise the number of taxa detected and optimising the sequencing depth. However, increasing the coverage of reference sequence databases would yield the most significant improvements in the accuracy of taxonomic assignments made using the P6 loop of the trnL region.

Global diversity and distribution of nitrogen-fixing bacteria in the soil.

Our knowledge of microbial biogeography has advanced in recent years, yet we lack knowledge of the global diversity of some important functional groups. Here, we used environmental DNA from 327 globally collected soil samples to investigate the biodiversity patterns of nitrogen-fixing bacteria by focusing on the nifH gene but also amplifying the general prokaryotic 16S SSU region. Globally, N-fixing prokaryotic communities are driven mainly by climatic conditions, with most groups being positively correlated with stable hot or seasonally humid climates. Among soil parameters, pH, but also soil N content were most often shown to correlate with the diversity of N-fixer groups. However, specific groups of N-fixing prokaryotes show contrasting responses to the same variables, notably in Cyanobacteria that were negatively correlated with stable hot climates, and showed a U-shaped correlation with soil pH, contrary to other N-fixers. Also, the non-N-fixing prokaryotic community composition was differentially correlated with the diversity and abundance of N-fixer groups, showing the often-neglected impact of biotic interactions among bacteria.

The multiscale feedback theory of biodiversity.

Plants and their environments engage in feedback loops that not only affect individuals, but also scale up to the ecosystem level. Community-level negative feedback facilitates local diversity, while the ability of plants to engineer ecosystem-wide conditions for their own benefit enhances local dominance. Here, we suggest that local and regional processes influencing diversity are inherently correlated: community-level negative feedback predominates among large species pools formed under historically common conditions; ecosystem-level positive feedback is most apparent in historically restricted habitats. Given enough time and space, evolutionary processes should lead to transitions between systems dominated by positive and negative feedbacks: species-poor systems should become richer due to diversification of dominants and adaptation of subordinates; however, new monodominants may emerge due to migration or new adaptations.

Syndesmosis Malposition Assessed on Weight-Bearing CT Is Common After Operative Fixation of Intra-articular Distal Tibia Plafond Fracture.

OBJECTIVES: To evaluate reliability of measurement techniques for syndesmosis position after operative fixation of distal tibia plafond fracture on weight-bearing computed tomography (WBCT), identify risk factors for syndesmosis malposition, and determine if syndesmosis malposition is associated with higher pain and lower physical function. DESIGN: Prospective cohort study. SETTING: Three Level 1 trauma centers. PARTICIPANTS: Twenty-six subjects who underwent open reduction and internal fixation of distal tibia plafond fractures with bilateral ankle WBCT 1 year or greater after injury were included in the study. INTERVENTION: Operative fixation of distal tibia plafond fracture. MAIN OUTCOME MEASUREMENT: Fibula position in the tibia incisura, injury characteristics, and patient-reported outcomes were the main outcome measurements. RESULTS: Interrater reliability for syndesmosis position measurements were excellent for the Phisitkul technique on both injured and healthy ankles (intraclass correlation coefficients [ICCs]: 0.93-0.98). The Nault technique demonstrated moderate-to-excellent interrater reliability (ICCs: 0.67-0.98), apart from the angle of rotation measurement (ICCs: 0.18-0.67). Sixteen of 26 subjects (62%) had syndesmosis malposition defined as >2 mm difference comparing the tibial-fibular relationship in injured and uninjured ankles using these 2 methods. Patients with syndesmosis malposition reported lower Foot and Ankle Ability Measure: Activities of Daily Living scores; other recorded patient-reported outcomes were not significantly different. CONCLUSIONS: Measurement techniques for syndesmosis position on WBCT were reliable after operative fixation of distal tibia plafond fracture. Syndesmosis malposition is common after these injuries and predicted impaired physical function. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Family case studies: absence of Pseudomonas aeruginosa transmission in bronchiectasis.

Two case reports show lack of Pseudomonas aeruginosa transmission, despite household contact, in non-cystic fibrosis bronchiectasis (NCFB). This supports evidence that in NCFB, P. aeruginosa is poorly transmitted. This affects management strategies. https://bit.ly/3PeOcHy.

Comparison of Early versus Late Below Knee Amputation After Trauma With Standardized Prosthetic Care.

Background: High energy, lower extremity trauma is associated with longstanding pain and functional limitations. The clinical decision to proceed with early amputation or limb salvage is often controversial. This study was designed to compare differences in complications, costs, and clinical outcomes of below knee amputation (BKA) performed early after injury or after attempted limb salvage in a hospital with standardized prosthetic care following amputation. Methods: This is a retrospective comparative study of subjects who underwent BKA for a traumatic injury at a single level 1 trauma center and received standardized prosthetic care from a single manufacturer from 1999-2016 with minimum 2-year post-amputation follow up. Outcomes collected included demographics, surgical management, unplanned re-operations, and hospital and prosthetic cost data 2 years from time of injury. Results: Overall, 79 subjects met criteria. Early amputation (EA) was defined by median duration between injury and amputation (6 weeks) with 41 subjects in the EA group and 38 subjects in the late amputation (LA) group. Subjects in the EA group were more likely to have open fractures, high energy mechanism, and less likely to have medical comorbidities. Post-amputation infection was common in both groups (17/41 (42%) vs 17/38 (45%), p=0.77). Subjects undergoing EA were more likely to require unplanned post-amputation revision, 22/41 (54%) versus 10/38 (27%), p=0.017. Hospital costs and prosthetics/orthotics costs from the time of injury to two years following amputation were comparable, with mean hospital EA costs $136,044 versus LA costs $125,065, p=0.38. Mean prosthetics/orthotics costs of EA subjects were $33,252 versus LA costs $37,684, p=0.59. Conclusion: Unplanned post-amputation revision surgeries were more common when BKA was performed early after trauma. Otherwise, outcomes and cost were comparable when amputation was performed early versus late. Level of Evidence: IV.

Malnutrition is Common and Increases the Risk of Adverse Medical Events in Older Adults With Femoral Fragility Fractures.

Background: Femoral fragility fractures are one of the most common injuries managed by orthopedic surgeons. Malnutrition influences the poor outcomes observed in this population. Our purpose was to assess the annual trends of malnutrition diagnosis and determine risk factors for malnutrition and complications in patients 65 years and older presenting with femoral fragility fractures. We hypothesized that malnutrition would increase the risk of postoperative wound infection, wound dehiscence, non-union, and mortality. Methods: The PearlDiver database was reviewed from 2010 to 2020. Patients ≥ 65-years-old with femur fractures treated with operative fixation were identified by CPT code. A preoperative diagnosis of malnourished state was defined by ICD-9 and ICD-10 codes and patients were divided into malnourished and non-malnourished cohorts. Patients were tracked for one year following operative fixation of a femoral fragility fracture for the occurrence of infection, wound dehiscence, nonunion and mortality. The rates of these complications were compared between malnourished and nonmalnourished cohorts. Results: There were 178,283 total femoral fragility fractures identified in patients aged 65-years or older. The overall prevalence of malnutrition diagnosis in this geriatric population was 12.8%. Documented malnutrition in femoral fragility fractures increased from 1.6% to 32.9% from 2010-2020 (P<0.0001). Compared to patients without malnutrition, patients with malnutrition are at increased risk of mortality (OR 1.31, 95% CI 1.2558 - 1.3752, p < 0.0001), are more likely to develop a wound infection (OR 1.49; 95% CI 1.252 - 1.7626; p < 0.0001), more likely to have a wound dehiscence (OR 1.55; 95% CI 1.3416 - 1.7949; p < 0.0001), and more likely to develop non-union (1.89; 95% CI 1.6946 - 2.1095; p < 0.0001). Multiple demographic variables were associated with malnutrition diagnosis including higher age, higher Charlson Comorbidity Index, female sex, dementia, and institutionalization. Parkinson's disease, feeding difficulty and institutionalization demographic variables had the highest risk of malnutrition. Conclusion: The current study found that malnutrition diagnosis significantly increases the risk of adverse medical events in elderly adults with femoral fragility fractures. The rates of malnutrition increased steadily from 2010-2020. This trend is likely a result of increased awareness and testing for malnutrition, not reflecting an actual increased prevalence of malnutrition. Multiple expected demographic variables are associated with diagnosis of malnutrition. Level of Evidence: III.

Reliability of Multifrequency Bioelectrical Impedance Analysis to Quantify Body Composition in Patients After Musculoskeletal Trauma.

Background: Changes in body composition, especially loss of lean mass, commonly occur in the orthopedic trauma population due to physical inactivity and inadequate nutrition. The purpose of this study was to assess inter-rater and intra-rater reliability of a portable bioelectrical impedance analysis (BIA) device to measure body composition in an orthopedic trauma population after operative fracture fixation. BIA uses a weak electric current to measure impedance (resistance) in the body and uses this to calculate the components of body composition using extensively studied formulas. Methods: Twenty subjects were enrolled, up to 72 hours after operative fixation of musculoskeletal injuries and underwent body composition measurements by two independent raters. One measurement was obtained by each rater at the time of enrollment and again between 1-4 hours after the initial measurement. Reliability was assessed using intraclass correlation coefficients (ICC) and minimum detectable change (MDC) values were calculated from these results. Results: Inter-rater reliability was excellent with ICC values for body fat mass (BFM), lean body mass (LBM), skeletal muscle mass (SMM), dry lean mass (DLM), and percent body fat (PBF) of 0.993, 0.984, 0.984, 0.979, and 0.986 respectively. Intra-rater reliability was also high for BFM, LBM, SMM, DLM, and PBF, at 0.994, 0.989, 0.990, 0.983, 0.987 (rater 1) and 0.994, 0.988, 0.989, 0.985, 0.989 (rater 2). MDC values were calculated to be 4.05 kg for BFM, 4.10 kg for LBM, 2.45 kg for SMM, 1.21 kg for DLM, and 4.83% for PBF. Conclusion: Portable BIA devices are a versatile and attractive option that can reliably be used to assess body composition and changes in lean body mass in the orthopedic trauma population for both research and clinical endeavors. Level of Evidence: III.