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ObjectivesOsteosarcoma is the most common primary bone malignancy.1 Due to its vague presenting features and rarity, osteosarcoma diagnosis is challenging. Evidence is mixed regarding whether time to diagnosis of osteosarcoma impacts patient outcome. The COVID-19 pandemic has been associated with paediatric malignancy diagnostic delay2 and prolonged diagnostic time has been associated with poor outcomes.3 The aims of this study were to identify:Does time to diagnosis impact patient outcome?Did the COVID-19 pandemic impact time to diagnosis?Are there any identifiable causes of delayed diagnosis?Can diagnosis be improved?MethodsA retrospective study of paediatric patients (<18 years) diagnosed with osteosarcoma at a tertiary centre between 2015–2022 focussing on time to diagnosis. We define time to diagnosis as time from first symptom onset to biopsy result. Patient data were collected from electronic records.ResultsThis cohort comprised 24 patients – 22 patients with primary tumours, 2 patients with secondary tumours. 21 patients had appendicular skeletal involvement, vs 3 patients with axial skeletal involvement.Average age at diagnosis was 11.3 years and average time to diagnosis was 72.4 days.Average time to diagnosis of patients in remission vs deceased patients did not significantly differ (77.4 days vs 65.9 days). Prolonged time to diagnosis was seen during and following the COVID-19 pandemic (109.6 days vs 52.9 days).Increased time to diagnosis was seen in tumours affecting the axial skeleton compared to the appendicular skeleton (133.7 days vs 59.0 days). Patients referred via 2-week wait had higher mortality rates compared to patients presenting via other pathways.4/24 patients had x-rays completed early in their diagnostic journey, but osteosarcoma was not considered at this stage.ConclusionProlonged time to diagnosis did not appear to influence mortality in this patient cohort. However, diagnostic delay is undoubtedly a major cause of emotional turmoil to the patient and their families.The COVID-19 pandemic appears to have negatively impacted osteosarcoma diagnostic pathways. Due to small sample size, results should be interpreted with caution. Review of current 2-week wait criteria, with more emphasis on atypical presentations, should occur.A normal x-ray does not exclude pathology. MRI should be considered in patients with persistent bony pain or swelling.Future work should investigate mortality rates before and after the COVID-19 pandemic, to determine if disruptions to diagnosis impacted mortality.ReferencesBeird, et al. Nature Reviews Disease Primers, 2022.Quarello, et al. Journal of Adolescent and Young Adult Oncology, 2022.Yoshida, et al. Journal of Bone Oncology, 2021.

Purpose Appendicular skeleton markers are commonly used for maturity assessment for Adolescent Idiopathic Scoliosis (AIS) patients. Traditionally, Risser has been a standard skeletal maturity assessment method. More recently, Sanders classification (SSMS), as a more comprehensive system, became popular, especially in decision-making for Vertebral Body Tethering (VBT). Thumb-Ossification Composite Index (TOCI), using ossification of thumb epiphyses, has been claimed to more accurately stage patients around their peak height velocity. However, growth peaks may occur separately at lower limbs and trunk. Hence, Cervical Vertebral Maturity (CVM), using cervical spine morphology, possesses a potential to better estimate spinal growth as it uses axial skeleton markers instead of appendicular skeleton markers. The aim of the study was to compare various axial and appendicular skeletal maturity assessment methods for longitudinal growth and curve modulation after VBT. Methods A retrospective analysis of prospectively collected data was conducted. Skeletal maturity was determined using Risser, SSMS, TOCI and CVM for each patient. Crosstabulations of axial vs. appendicular markers were formed to analyze their concordance and discordance. Logistic and logarithmic regression models were run to assess longitudinal growth (postoperative height gain and leg-length growth) and curve modulation (follow-up instrumented Cobb correction after index operation), respectively. Models were compared using Akaike information criterion (AIC). Results 34 patients (32 F/2 M, mean age: 12.8 ± 1.5 years, mean follow-up: 47.7 (24–80) months) were included. The median preoperative maturity stages were: Risser: 1 (-1–4), SSMS: 4 (1–7), TOCI: 6 (1–8) and CVM: 4 (1–6). At latest follow-up, all patients reached skeletal maturity. Concordance and discordance were observed between axial vs. appendicular systems that demonstrated a range of possible distributions of CVM, where trunk peak height velocity occurred before, simultaneously with or after the standing height peak height velocity. R-squared values for Risser, SSMS, TOCI and CVM were 0.701, 0.783, 0.810 and 0.811, respectively, for prediction of final height; 0.759, 0.821, 0.831 and 0.775 for final leg-length, and 0.507, 0.588, 0.668 and 0.673 for curve modulation. Delta AIC values demonstrated that different skeletal maturity assessment methods provided distinctive information regarding follow-up height gain, leg-length growth and curve behavior. Conclusions Risser score provided considerably less information for all three outcome variables. TOCI and SSMS provided substantial information regarding remaining leg-length assessments, while in terms of assessment of total height gain and curve modulation after surgery, CVM and TOCI offered substantial information and SSMS offered strong information. Mutual use of axial and appendicular markers may provide valuable insight concerning timing of surgery and magnitude of surgical correction.

Despite the importance of body composition in athletes, reference sex- and sport-specific body composition data are lacking. We aim to develop reference values for body composition and anthropometric measurements in athletes. Body weight and height were measured in 898 athletes (264 female, 634 male), anthropometric variables were assessed in 798 athletes (240 female and 558 male), and in 481 athletes (142 female and 339 male) with dual-energy X-ray absorptiometry (DXA). A total of 21 different sports were represented. Reference percentiles (5th, 25th, 50th, 75th, and 95th) were calculated for each measured value, stratified by sex and sport. Because sample sizes within a sport were often very low for some outcomes, the percentiles were estimated using a parametric, empirical Bayesian framework that allowed sharing information across sports. We derived sex- and sport-specific reference percentiles for the following DXA outcomes: total (whole body scan) and regional (subtotal, trunk, and appendicular) bone mineral content, bone mineral density, absolute and percentage fat mass, fat-free mass, and lean soft tissue. Additionally, we derived reference percentiles for height-normalized indexes by dividing fat mass, fat-free mass, and appendicular lean soft tissue by height squared. We also derived sex- and sport-specific reference percentiles for the following anthropometry outcomes: weight, height, body mass index, sum of skinfold thicknesses (7 skinfolds, appendicular skinfolds, trunk skinfolds, arm skinfolds, and leg skinfolds), circumferences (hip, arm, midthigh, calf, and abdominal circumferences), and muscle circumferences (arm, thigh, and calf muscle circumferences). These reference percentiles will be a helpful tool for sports professionals, in both clinical and field settings, for body composition assessment in athletes.

BackgroundResearch into artificial intelligence (AI)-based fracture detection in children is scarce and has disregarded the detection of indirect fracture signs and dislocations.ObjectiveTo assess the diagnostic accuracy of an existing AI-tool for the detection of fractures, indirect fracture signs, and dislocations.Materials and methodsAn AI software, BoneView (Gleamer, Paris, France), was assessed for diagnostic accuracy of fracture detection using paediatric radiology consensus diagnoses as reference. Radiographs from a single emergency department were enrolled retrospectively going back from December 2021, limited to 1,000 radiographs per body part. Enrolment criteria were as follows: suspected fractures of the forearm, lower leg, or elbow; age 0–18 years; and radiographs in at least two projections.ResultsLower leg radiographs showed 607 fractures. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were high (87.5%, 87.5%, 98.3%, 98.3%, respectively). Detection rate was low for toddler’s fractures, trampoline fractures, and proximal tibial Salter-Harris-II fractures. Forearm radiographs showed 1,137 fractures. Sensitivity, specificity, PPV, and NPV were high (92.9%, 98.1%, 98.4%, 91.7%, respectively). Radial and ulnar bowing fractures were not reliably detected (one out of 11 radial bowing fractures and zero out of seven ulnar bowing fractures were correctly detected). Detection rate was low for styloid process avulsions, proximal radial buckle, and complete olecranon fractures. Elbow radiographs showed 517 fractures. Sensitivity and NPV were moderate (80.5%, 84.7%, respectively). Specificity and PPV were high (94.9%, 93.3%, respectively). For joint effusion, sensitivity, specificity, PPV, and NPV were moderate (85.1%, 85.7%, 89.5%, 80%, respectively). For elbow dislocations, sensitivity and PPV were low (65.8%, 50%, respectively). Specificity and NPV were high (97.7%, 98.8%, respectively).ConclusionsThe diagnostic performance of BoneView is promising for forearm and lower leg fractures. However, improvement is mandatory before clinicians can rely solely on AI-based paediatric fracture detection using this software.

Intensifying macrovertebrate reconnaissance together with refined age-dating of mid-Cretaceous assemblages in recent decades is producing a more nuanced understanding of the impact of the Cretaceous Thermal Maximum on terrestrial ecosystems. Here we report discovery of a new early-diverging ornithopod, Iani smithi gen. et sp. nov., from the Cenomanian-age lower Mussentuchit Member, Cedar Mountain Formation of Utah, USA. The single known specimen of this species (NCSM 29373) includes a well-preserved, disarticulated skull, partial axial column, and portions of the appendicular skeleton. Apomorphic traits are concentrated on the frontal, squamosal, braincase, and premaxilla, including the presence of three premaxillary teeth. Phylogenetic analyses using parsimony and Bayesian inference posit Iani as a North American rhabdodontomorph based on the presence of enlarged, spatulate teeth bearing up to 12 secondary ridges, maxillary teeth lacking a primary ridge, a laterally depressed maxillary process of the jugal, and a posttemporal foramen restricted to the squamosal, among other features. Prior to this discovery, neornithischian paleobiodiversity in the Mussentuchit Member was based primarily on isolated teeth, with only the hadrosauroid Eolambia caroljonesa named from macrovertebrate remains. Documentation of a possible rhabdodontomorph in this assemblage, along with published reports of an as-of-yet undescribed thescelosaurid, and fragmentary remains of ankylosaurians and ceratopsians confirms a minimum of five, cohabiting neornithischian clades in earliest Late Cretaceous terrestrial ecosystems of North America. Due to poor preservation and exploration of Turonian–Santonian assemblages, the timing of rhabdodontomorph extirpation in the Western Interior Basin is, as of yet, unclear. However, Iani documents survival of all three major clades of Early Cretaceous neornithischians (Thescelosauridae, Rhabdodontomorpha, and Ankylopollexia) into the dawn of the Late Cretaceous of North America.

Species richness is strikingly uneven across taxonomic groups at all hierarchical levels, but the reasons for this heterogeneity are poorly understood. It is well established that morphological diversity (disparity) is decoupled from taxonomic diversity, both between clades and across geological time. Morphological complexity has been much less studied, but there is theory linking complexity with differential diversity across groups. Here we devise an index of complexity from the differentiation of the fore and hind limb pairs for a sample of 983 species of extant birds. We test the null hypothesis that this index of morphological complexity is uncorrelated with clade diversity, revealing a significant and negative correlation between the species richness of clades and the mean morphological complexity of those clades. Further, we find that more complex clades tend to occupy a smaller number of dietary and habitat niches, and that this proxy for greater ecological specialisation correlates with lower species richness. Greater morphological complexity in the appendicular skeleton therefore appears to hinder the generation and maintenance of species diversity. This may result from entrenchment into morphologies and ecologies that are less capable of yielding further diversity. Biodiversity is unevenly distributed across the tree of life, and theoretical work suggests that biological complexity may be influential in forming these patterns. Here, Brinkworth et al. have shown that bird clades with more complex appendicular skeletons tend to have lower extant species richness.

Osteosarcoma (OS) is the most common bone tumor in both dogs and humans. It predominantly occurs in the appendicular skeleton, with about 25% of cases occurring within the axial skeleton. Progression of local disease is often the life-limiting factor for patients with axial OS, in contrast to appendicular OS, where local disease is addressed surgically, and metastatic disease remains the primary obstacle. While OS is a rare human cancer, limiting the availability of samples, its higher incidence in dogs provides a valuable comparative model for study. Both canines and humans share commonalities in clinical presentation, but dogs have an accelerated progression. Similarly, complex structural genetic changes define appendicular OS in both dogs and people, but it is unclear whether the genomic landscape of axial OS exhibits different alterations that may separate it from appendicular OS. We performed pilot whole genome sequencing of canine primary oral (maxillary or mandibular) OS tumors (n = 8) and matched normal tissue. We found that the genetics of canine oral OS largely parallel the genetics of canine appendicular OS, including an overall low number of recurrent point mutations affecting the same gene ( TP53 and SETD2, 3/8 samples). Structural variants dominated the landscape of mutational changes, with recurrent variants in DMD (4/8) and DLG2 (3/8) found at a similar incidence to appendicular OS. This pilot suggests genomic similarities between oral and appendicular OS.

Demonstrating the clinical consequences of osteosarcopenic obesity (OSO) is complex. This study evaluated clinical manifestations and factors associated with bone and muscle loss in Koreans with obesity. This cross-sectional observational study enrolled Koreans with obesity aged ≥ 50 years from the Korea National Health and Nutrition Examination Survey. Clinical manifestations were compared among four groups: obesity (O), sarcopenic obesity (SO), osteopenic obesity (OO), and OSO. Factors associated with appendicular skeletal muscle mass (ASM) or bone mineral density (BMD) were evaluated. OSO increases with age in both sexes. Men with SO and OSO had increased cardiometabolic diseases and markers, percentages of body fat (BF %), and trunk fat (TF %), and decreased limb fat percentage (LF %). Women with SO and OSO had increased metabolic markers, BF %, and TF % but those with OSO had increased cardiometabolic diseases and lower LF %. Both sexes with OSO had decreased ASM and vitamin D, and higher vitamin D deficiency. BF % was negatively associated with ASM and femur BMD in both sexes. TF % was negatively and LF % was positively associated with ASM in both sexes and with femur BMD in women. Vitamin D was positively associated with femur BMD in men and with ASM and BMD at all sites in women. ASM and BMD were positively associated with each other. Appendicular muscle loss is metabolically significant regardless of bone loss in men; however, appendicular muscle loss with bone loss is metabolically more significant in women. Regional body composition, fat distribution, and vitamin D deficiency were associated with OSO phenotype in both sexes.

The fossil record of Mesozoic terrestrial squamates is very poor in the Southern Hemisphere. Currently recognised species represent less than 6% of the number described for Laurasian landmasses. Here, we describe the most complete Late Cretaceous terrestrial squamate known from South America. The specimen was collected in the Maastrichtian Allen Formation of northern Patagonia (Río Negro Province, Argentina) and represents a single individual that preserves a partial skull, vertebrae, and appendicular bones. The skeleton shows a unique combination of character states that allow erecting the new genus and species Paleoteius lakui . Morphological phylogenetic analyses recovered Paleoteius lakui as a Scincomorpha more closely related to Xantusiidae than to other species. When a molecular backbone is applied to those analyses, Paleoteius lakui is found outside Scincomorpha, but within a clade composed of Jurassic to Palaeogene species found as non-crown scincomorphans in previous studies. The affinities of Paleoteius lakui either as a stem-xantusiid or as a more early-diverging clade indicate the presence of a yet unrecognised lineage of squamates in South America. Paleoteius lakui is related to Laurasian forms with a probable cosmopolitan ancestry during the Jurassic–earliest Cretaceous. The new finding helps fill the still poorly known record of Mesozoic Gondwanan squamates.