Bi-allelic variants in MYH3 cause recessively-inherited arthrogryposis.

Arthrogryposis is a clinical feature defined by congenital joint contractures in two or more different body areas which occurs in between 1/3000 and 1/5000 live births. Variants in multiple genes have been associated with distal arthrogryposis syndromes. Heterozygous variants in MYH3 have been identified to cause the dominantly-inherited distal arthrogryposis conditions, Freeman-Sheldon syndrome, Sheldon-Hall syndrome, and multiple pterygium syndrome. In contrast, MYH3 variants underlie both dominantly and recessively inherited Contractures, Pterygia, and Spondylocarpotarsal Fusion syndromes (CPSFS) which are characterized by extensive bony abnormalities in addition to congenital contractures. Here we report two affected sibs with distal arthrogryposis born to unaffected, distantly related parents. Sequencing revealed that both sibs were homozygous for two ultra-rare MYH3 variants, c.3445G>A (p.Glu1149Lys) and c.4760T>C (p.Leu1587Pro). Sequencing and deletion/duplication analysis of 169 other arthrogryposis genes yielded no other compelling candidate variants. This is the first report of biallelic variants in MYH3 being implicated in a distal arthrogryposis phenotype without the additional features of CPSFS. Thus, akin to CPSFS, both dominant and recessively inherited distal arthrogryposis can be caused by variants in MYH3.

Infected popliteal pseudoaneurysm in a youth basketball player: A case report and brief review of the literature.

INTRODUCTION: An infected popliteal pseudoaneurysm has never been described in the pediatric population. Physicians need to be aware of its presentation and management, in order to diagnose and treat this medical condition adequately. METHODS: We describe the case of a 14-year-old boy who developed myositis and cellulitis centered at the popliteal fossa after playing basketball. A treatment of intravenous cefazolin was started. 5 days later, he experienced a knee pain flare-up, which turned out to be a popliteal pyomyositis with a pseudoaneurysm of the popliteal artery. A saphenous vein graft bypass of the popliteal artery and an excision of the popliteal pseudoaneurysm were performed. Intravenous cefazolin was continued for 6 weeks and prophylactic acetylsalicylic acid for 6 months. RESULTS AND CONCLUSION: This case highlighted the importance of repeating radiologic investigations if a patient suffering from soft tissue infection has persistent pain after several days of appropriate antibiotics. A popliteal pseudoaneurysm can be diagnosed with ultrasound imaging and treated with a popliteal-popliteal bypass. Our patient needed a catheter-guided dilation of the anastomosis at the vein graft 6 months post-surgery, and then evolved favorably and went back to playing basketball 6 months post-dilation.

Langerhans Cell Histiocytosis With Vertebral Involvement Diagnosed and Treated Over the Last 15 Years in a Single Canadian Pediatric Academic Institution.

We report 11 children with vertebral lesion of Langerhans cell histiocytosis (LCH) diagnosed and treated between 2000 and 2015. Vertebral lesions were usually present at LCH diagnosis. No child developed neurologic symptoms. Among 29 vertebral lesions, only 2 were unstable. Chemotherapy was used in all children but 3. A LCH recurrence was observed in 6 patients, involving vertebrae in 4 cases. All children were disease-free at their last follow-up. Sequelae were more often radiologic than clinical. Since potential recurrences and incomplete bone regeneration exist, discussion about optimal treatment and long-term follow-up of vertebral lesions are essential.

Phenotypic and Functional Changes in Peripheral Blood Natural Killer Cells in Crohn Disease Patients.

We investigated activation status, cytotoxic potential, and gut homing ability of the peripheral blood Natural Killer (NK) cells in Crohn disease (CD) patients. For this purpose, we compared the expression of different activating and inhibitory receptors (KIR and non-KIR) and integrins on NK cells as well as their recent degranulation history between the patients and age-matched healthy controls. The study was conducted using freshly obtained peripheral blood samples from the study participants. Multiple color flow cytometry was used for these determinations. Our results show that NK cells from treatment-naïve CD patients expressed higher levels of activating KIR as well as other non-KIR activating receptors vis-à-vis healthy controls. They also showed increased frequencies of the cells expressing these receptors. The expression of several KIR and non-KIR inhibitory receptors tended to decrease compared with the cells from healthy donors. NK cells from the patients also expressed increased levels of different gut-homing integrin molecules and showed a history of increased recent degranulation events both constitutively and in response to their in vitro stimulation. Furthermore, treatment of the patients tended to reverse these NK cell changes. Our results demonstrate unequivocally, for the first time, that peripheral blood NK cells in treatment-naïve CD patients are more activated and are more poised to migrate to the gut compared to their counterpart cells from healthy individuals. Moreover, they show that treatment of the patients tends to normalize their NK cells. The results suggest that NK cells are very likely to play a role in the immunopathogenesis of Crohn disease.

Predicting lowest hemoglobin level and risk of blood transfusion in spinal fusion surgery for adolescent idiopathic scoliosis.

PURPOSE: The aim of this study was to evaluate the factors associated with timing of lowest hemoglobin (Hb) level and the need for postoperative blood transfusion in posterior spinal fusion for adolescent idiopathic scoliosis. METHODS: We conducted a retrospective review of all adolescent scoliosis patients undergoing posterior spinal fusion at our institution, 2002-2014. Surgery consisted of segmental pedicle screw fixation using multi-level pedicle screws. Blood-saving techniques were used in all patients. Data included Cobb angle, pre- and postoperative Hb levels, preoperative autologous blood donation (PABD), surgery duration, and allogeneic or autologous transfusion. We used linear and logistic regressions for statistical analysis. RESULTS: There were 456 patients (402 female, 54 male), mean age 16 ± 5 years. Lowest Hb was observed on postoperative Days 2 (32.2%) and 3 (33.3%); 45.1% of postoperative transfusions occurred on Day 2. One hundred and eighty-eight (41%) patients who provided PABD had significantly lower preoperative Hb and received more transfusions intraoperatively (22.6% vs. 5.2%) and postoperatively (20% vs. 6.3%) than others. Probability of transfusion increased 49.6 (95% CI 17.40-141.37) times with preoperative Hb < 11 g/dL as compared to preoperative Hb > 14 g/dL. Probability of transfusion increased 4.3- and 9.8-fold when surgery duration exceeded 5 and 6 h, respectively. Probability of transfusion increased 3.3- and 5.3-fold with Cobb angle > 70° and 80°, respectively. CONCLUSIONS: We identified clear patient-specific perioperative parameters that affect risk of perioperative blood transfusion, including Cobb angle, PABD and preoperative Hb. Hb measurement beyond postoperative Day 3 is considered unnecessary unless clinically indicated. These slides can be retrieved under Electronic Supplementary Material.

Validation of the French version of the KOOS-child questionnaire.

PURPOSE: The Knee Injury Osteoarthritis Outcome Score (KOOS) questionnaire is one of the frequently used outcome scores in pediatric studies. However, a recent study demonstrated that the pediatric population had a limited understanding of some of its questions. Therefore, the KOOS-Child questionnaire was developed specifically for this population. Our team produced a French adaptation based on the English version. The objective of the current study was to validate the French adaptation of the KOOS-Child questionnaire. METHODS: After ethic board approval, the questionnaire was translated from English to French by two French speaking orthopedic surgeons. Following consensus, the translated version was retranslated to English by a professional translator. A group of experts compared the original and back translated version and decided on a final adapted questionnaire version. Ninety-nine 8-16 year-old patients were prospectively recruited from our pediatric orthopedic surgery clinic. Twenty-one control participants and 78 patients suffering from knee pain were recruited. The participants were asked to answer the translated French version of the KOOS-Child questionnaire and two validated French pediatric quality of life surveys. RESULTS: Statistical analysis demonstrated no statistically significant demographic difference between the control population and the patients suffering from a knee pathology. The mean for the five different domains of the KOOS-Child questionnaire showed statistical differences (p < 0.001) between the two groups. Construct validity was demonstrated through testing of previously validated hypothesis of correlation. Internal consistency was also confirmed in injured patients. CONCLUSIONS: In conclusion, the current study results demonstrate good to excellent internal consistency, good construct validity and inconclusive discriminant capacity of the French adaptation of the KOOS-Child questionnaire. LEVEL OF EVIDENCE: II.

Lipid and lipoprotein abnormalities in acute lymphoblastic leukemia survivors.

Survivors of acute lymphoblastic leukemia (ALL), the most common cancer in children, are at increased risk of developing late cardiometabolic conditions. However, the mechanisms are not fully understood. This study aimed to characterize the plasma lipid profile, Apo distribution, and lipoprotein composition of 80 childhood ALL survivors compared with 22 healthy controls. Our results show that, despite their young age, 50% of the ALL survivors displayed dyslipidemia, characterized by increased plasma triglyceride (TG) and LDL-cholesterol, as well as decreased HDL-cholesterol. ALL survivors exhibited lower plasma Apo A-I and higher Apo B-100 and C-II levels, along with elevated Apo C-II/C-III and B-100/A-I ratios. VLDL fractions of dyslipidemic ALL survivors contained more TG, free cholesterol, and phospholipid moieties, but less protein. Differences in Apo content were found between ALL survivors and controls for all lipoprotein fractions except HDL3 HDL2, especially, showed reduced Apo A-I and raised Apo A-II, leading to a depressed Apo A-I/A-II ratio. Analysis of VLDL-Apo Cs disclosed a trend for higher Apo C-III1 content in dyslipidemic ALL survivors. In conclusion, this thorough investigation demonstrates a high prevalence of dyslipidemia in ALL survivors, while highlighting significant abnormalities in their plasma lipid profile and lipoprotein composition. Special attention must, therefore, be paid to these subjects given the atherosclerotic potency of lipid and lipoprotein disorders.

Association between oropharyngeal carriage of Kingella kingae and osteoarticular infection in young children: a case-control study.

BACKGROUND: Kingella kingae has been increasingly identified in patients with osteoarticular infections. Our main objective was to evaluate the association between carriage of K. kingae in the oropharynx of preschool children and osteoarticular infections. METHODS: We conducted this prospective case-control study in 2 tertiary care pediatric hospitals (Canada and Switzerland) between 2014 and 2016. Potential cases were children aged 6 to 48 months with a presumptive diagnosis of osteoarticular infection according to the treating emergency physician. Confirmed cases were those with diagnosis of osteomyelitis or septic arthritis proven by positive findings on technetium-labelled bone scan or magnetic resonance imaging or identification of a microorganism in joint aspirate or blood. For each case, we recruited 4 age-matched controls from among children presenting to the same emergency department for trauma. The independent variable was presence of oropharyngeal K. kingae DNA identified by a specific polymerase chain reaction assay. We determined the association between oropharyngeal carriage of K. kingae and definitive osteoarticular infection. RESULTS: The parents of 77 children admitted for suspected osteoarticular infection and 286 controls were invited to participate and provided informed consent. We identified K. kingae in the oropharynx of 46 (71%) of 65 confirmed cases and 17 (6%) of 286 controls; these results yielded an odds ratio of 38.3 (95% confidence interval 18.5-79.1). INTERPRETATION: Detection of oropharyngeal K. kingae was strongly associated with osteoarticular infection among children presenting with symptoms suggestive of such infection.

Ultrasound evaluation of foot deformities in infants.

Foot deformity in infants is the most common congenital musculoskeletal condition. A precise diagnosis can sometimes be impossible to establish clinically. Radiologic imaging plays a major role in the evaluation of musculoskeletal abnormalities. However conventional imaging techniques, such as plain radiographs of the foot, are of very little help in this age group because of the lack of ossification of the tarsal bones. US presents a significant advantage because it permits the visualization of cartilaginous structures. This leads to the detailed assessment of foot deformities in infants. Furthermore, US can also be used as a dynamic imaging modality. Different scanning views are beneficial to evaluate the complete anatomy of the foot; depending on the suspected clinical diagnosis, some planes are more informative to display the pathological features of a specific deformity. We describe the US findings of five of the most common foot deformities referred to our pediatric orthopedic clinic (clubfoot, simple metatarsus adductus, skewfoot, and oblique and vertical talus). For each deformity we propose a specific imaging protocol based on US to provide an accurate diagnosis. US is a complementary tool to the clinical examination for determining the diagnosis and the severity of the deformity and also for monitoring the efficacy of treatment. Radiologists investigating foot deformities in infants should consider using US for the detailed assessment of the foot in this age group.

Spondylolisthesis, Sacro-Pelvic Morphology, and Orientation in Young Gymnasts.

STUDY DESIGN: Cross-sectional evaluation of sacro-pelvic morphology and orientation as well as spondylolisthesis prevalence in a cohort of young gymnasts. OBJECTIVE: To evaluate the prevalence of spondylolisthesis in a cohort of gymnasts, as well as the associated demographic characteristics and sacro-pelvic morphology and orientation. SUMMARY OF BACKGROUND DATA: Numerous studies have shown that sagittal sacro-pelvic morphology and orientation is abnormal in spondylolisthesis. Sacro-pelvic morphology and orientation in gymnasts and their relationship with spondylolisthesis have never been analyzed. METHODS: Radiologic evaluation of 92 gymnasts was performed to identify spondylolisthesis, and to measure pelvic incidence, pelvic tilt, sacral slope, and sacral table angle. In the presence of spondylolisthesis, the slip percentage was measured. Different demographic and training characteristics were evaluated. Radiographic parameters were compared with reference values published for asymptomatic children and adolescents, and for subjects with spondylolisthesis. RESULTS: A 6.5% prevalence of spondylolisthesis was found in our cohort. The weekly training schedule was the only statistically significant different demographic characteristic between the 2 groups, at 20.6±5.4 versus 14.4±5.6 h/wk for subjects with and without spondylolisthesis, respectively. Pelvic incidence, pelvic tilt, sacral slope, and sacral table angle were 69±20, 15±13, 54±11, and 88±7 degrees in gymnasts with spondylolisthesis, and 53±11, 10±6, 43±9, and 94±6 degrees in gymnasts without spondylolisthesis, respectively. When compared with asymptomatic individuals, pelvic incidence and pelvic tilt were slightly superior in gymnasts without spondylolisthesis. Pelvic incidence, sacral slope, and sacral table angle were significantly different between gymnasts with and without spondylolisthesis. CONCLUSIONS: The prevalence of spondylolisthesis in young gymnasts was similar to that observed in the general population. Sagittal sacro-pelvic morphology and orientation was abnormal in gymnasts with spondylolisthesis. Sagittal sacro-pelvic morphology and orientation was also slightly different in gymnasts without spondylolisthesis when compared with the normal population. The present study supports an association between spondylolisthesis and abnormal sacro-pelvic orientation and morphology.

Quantitative pivot shift assessment using combined inertial and magnetic sensing.

PURPOSE: The purpose of the study was to demonstrate the feasibility of a new measurement system using micro-electromechanical systems (MEMS)-based sensors for quantifying the pivot shift phenomenon. METHODS: The pivot shift test was performed on 13 consecutive anterior cruciate ligament-deficient subjects by an experienced examiner while femur and tibia kinematics were recorded using two inertial sensors each composed of an accelerometer, gyroscope and magnetometer. The gravitational component of the acquired data was removed using a novel method for estimating sensor orientations. Correlation between the clinical pivot shift grade and acceleration and velocity parameters was measured using Spearman's rank correlation coefficients. RESULTS: The pivot shift phenomenon was best characterized as a drop in femoral acceleration observed at the time of reduction. The correlation between the femoral acceleration drop and the clinical grade was shown to be very strong (r = 0.84, p < 0.0001). CONCLUSIONS: The present study demonstrates the feasibility of quantifying the pivot shift using MEMS-based sensors and removing the gravitational component of acceleration using an estimation of sensor orientation for improved correlation to the clinical grade.

Microarray expression profiling identifies genes with altered expression in Adolescent Idiopathic Scoliosis.

PURPOSE: Adolescent Idiopathic Scoliosis (AIS) is considered a complex genetic disease, in which malfunctioning or dysregulation of one or more genes has been proposed to be responsible for the expressed phenotype. However, to date, no disease causing genes has been identified and the pathogenesis of AIS remains unknown. The aim of this study is, therefore, to identify specific molecules with differing expression patterns in AIS compared to healthy individuals. METHODS: Microarray analysis and quantitative RT-PCR have examined differences in the gene transcription profile between primary osteoblasts derived from spinal vertebrae of AIS patients and those of healthy individuals. RESULTS: There are 145 genes differentially expressed in AIS osteoblasts. A drastic and significant change has been noted particularly in the expression levels of Homeobox genes (HOXB8, HOXB7, HOXA13, HOXA10), ZIC2, FAM101A, COMP and PITX1 in AIS compared to controls. Clustering analysis revealed the interaction of these genes in biological pathways crucial for bone development, in particular in the differentiation of skeletal elements and structural integrity of the vertebrae. CONCLUSIONS: This study reports on the expression of molecules that have not been described previously in AIS. We also provide for the first time gene interaction pathways in AIS pathogenesis. These genes are involved in various bone regulatory and developmental pathways and many of them can be grouped into clusters to participate in a particular biological pathway. Further studies can be built on our findings to further elucidate the association between different biological pathways and the pathogenesis of AIS.

Development and validation of a French-language cross-cultural adaptation of the Pedi-IKDC Questionnaire.

BACKGROUND: The Pedi-IKDC is an English-language, knee-specific, paediatric questionnaire used by orthopaedic surgeons around the world as a valuable patient-reported outcome measure (PROM). The objective of this study was thus to extend the applicability of the Pedi-IKDC to French-speaking Canadian patients, for both clinical practice and research, by developing a French-language cross-cultural adaptation of the original version. HYPOTHESIS: The French adaptation of the Pedi-IKDC is valid and reliable for evaluating French-speaking children with knee conditions. PATIENTS AND METHODS: The Pedi-IKDC was translated to French by a panel of orthopaedic surgeons then back-translated by a professional translator. The original English version and the back-translation were compared to assess their similarity and confirm the faithfulness of the French translation. The validity of the French version was then tested at a major paediatric hospital in French-speaking Canada, in 203 children, including 163 with knee pain and 40 without knee symptoms. Internal consistency, construct validity, and discriminant capacity of the French version were assessed. RESULTS: Internal consistency of the Pedi-IKDC adaptation was excellent (Cronbach's alpha, 0.934 in the knee-pain group). Construct validity was robust, with all nine hypotheses adapted from the original Pedi-IKDC article demonstrating strong (n=7) or moderate (n=2) correlations (p<0.001). The evaluation of discriminant capacity identified no statistically significant score differences according to most of the respondent characteristics (body mass index, age group, type of diagnosis, and type of treatment). However, scores differed significantly between females and males. DISCUSSION: The French-language cross-cultural adaptation of the Pedi-IKDC obtained using a universally recognized method for translating PROMs demonstrated good performance, with psychometric properties similar to those of the original Pedi-IKDC and of its Danish, Italian, and Russian adaptations. LEVEL OF EVIDENCE: II.

Ultrasound measurements in clubfoot treated with the Ponseti method and risk factors for recurrence: A retrospective study.

Background: Recurrence remains the main challenge in the treatment of clubfoot. The primary goal of this study is to determine if ultrasound measurements are associated with recurrence after successful management with the Ponseti method. Furthermore, other factors are identified which can be associated with recurrence of the deformity. Methods: Seventy-six infants (114 idiopathic clubfeet), all treated with the Ponseti technique were reviewed. All patients had an ultrasound evaluation by the same radiologist at the beginning of the treatment. Recurrence, defined as the need to return to Ponseti casting, was recorded at a mean follow-up of 5 years. Measurements of association with recurrence were obtained for the following ultrasound measures: the medial talonavicular displacement (MTa-N), the medial malleolus to navicular distance (MM-N), the talocalcaneal angle (Ta-C), and the distal tibial physis to proximal calcaneal apophysis distance (Ti-C). Subsequently, a multivariate logistic regression analysis modeling recurrence examined patients' characteristics, compliance, Achilles tenotomy, and ultrasound measurements. Results: Recurrence rate was 22% noted in 17 patients. On univariate analysis, relapse was associated with increased MTa-N (p = 0.038), decreased MM-N (p = 0.008), and decreased Ti-C (p = 0.023). On multivariate analysis, we identified the Ti-C as the only ultrasound measurement significantly associated with recurrence (p = 0.026). Other significant predictors for relapse in this study were noncompliance with orthosis (OR = 139.0 (95% CI: 8.7-2224.0), p < 10-3), and omitting percutaneous Achilles tenotomy in clubfoot treatment (OR = 23.9 (95% CI: 1.2-493.6), p = 0.041). Conclusion: The Ti-C sonographic measurement at the start of treatment can be a useful adjunct to help identify high-risk patients for recurrence of deformity. Non-compliance with bracing and omitting percutaneous Achilles tenotomy are also predictive factors. Level of evidence: Prognostic study, Level III.

Complication rates following all-epiphyseal ACL reconstructions in skeletally immature patients: A retrospective case series study.

ABSTRACT: The aim was to evaluate the safety of a physeal-sparing anterior cruciate ligament reconstruction technique (ACLR), performed with Orthopediatrics (Warsaw, IN) equipment, by assessing complications.Skeletally immature patients who underwent all-epiphyseal ACLR between 2015 and 2017 with postoperative follow-up were included in this retrospective study. Complications, demographic, clinical, surgical, and imaging data was retrieved from an urban tertiary pediatric hospital database. Physeal status, limb-length discrepancies (LLD), and angular deformities were assessed on preoperative and postoperative radiographs, growth disturbances were reported, and initial and follow-up diameters of tunnels were compared.Nineteen ACLRs were included from 18 patients, 4 females and 14 males, with bone age at surgery of 13.3 ± 1.0 years. At a mean follow-up of 19.2 ±â€Š10.1 months, there were no symptomatic growth disorders requiring intervention. There were: 2 (11.1%) unilateral early physeal closures, 2 (10.5%) new angular deformities (5°-10°), 4 (22.2%) LLD (1-2 cm), 1 (5.6%) contralateral ACLR, 1 (5.6%) femoral screw removal, 2 (10.5%) graft ruptures, and 1 meniscal tear (5.3%). Mean tunnel widening was 1.7 mm and 1.5 mm on the femoral and tibial side, respectively, and no massive osteolysis was recorded at the polyetheretherketone implant site.The complication rates were comparable to those in similar studies, with no growth-related complications at 19.2 months.

Automatic bone maturity grading from EOS radiographs in Adolescent Idiopathic Scoliosis.

Adolescent Idiopathic Scoliosis (AIS) is a deformation of the spine and it is routinely diagnosed using posteroanterior and lateral radiographs. The Risser sign used in skeletal maturity assessment is commonly accepted in AIS patient's management. However, the Risser sign is subject to inter-observer variability and it relies mainly on the observation of ossification on the iliac crests. This study proposes a new machine-learning-based approach for Risser sign skeletal maturity assessment using EOS radiographs. Regions of interest including right and left humeral heads; left and right femoral heads; and pelvis are extracted from the radiographs. First, a total of 24 image features is extracted from EOS radiographs using a ResNet101-type convolutional neural network (CNN), pre-trained from the ImageNet database. Then, a support vector machine (SVM) algorithm is used for the final Risser sign classification. The experimental results demonstrate an overall accuracy of 84%, 78%, and 80% respectively for iliac crests, humeral heads, and femoral heads. Class activation maps using Grad-CAM were also investigated to understand the features of our model. In conclusion, our machine learning approach is promising to incorporate a large number of image features for different regions of interest to improve Risser grading for skeletal maturity. Automatic classification could contribute to the management of AIS patients.

Association between genome-wide association studies reported SNPs and pediatric-onset Crohn's disease in Canadian children.

A recent pediatric-focused genome-wide association study has implicated three novel susceptibility loci for Crohn' disease (CD).We aimed to investigate whether the three recently reported and other previously reported genes/loci were also associated with CD in Canadian children. A case-control design was implemented at three pediatric gastroenterology clinics in Canada. Children <19 years of age with a confirmed diagnosis of CD were recruited along with controls. Single nucleotide polymorphisms (SNPs) in 19 reported genes/loci were genotyped. Associations between individual SNPs and CD were examined. A total of 563 cases and 553 controls were studied. The mean (+/-SD) age of the cases was 12.3 (+/-3.2) years. Most cases were male (56.0%), had ileo-colonic disease (L3 +/- L4, 48.8%) and inflammatory behavior (B1 +/- p, 87.9%) at diagnosis. Allelic association analysis (two-tailed) showed that 8 of the 19 targeted SNPs were significantly associated with overall susceptibility for CD. Associations with one additional SNP was borderline non-significant. Significantly associated SNPs included SNPs rs1250550 (p = 0.026) and rs8049439 (p = 0.04), recently reported to be specifically associated with pediatric-onset CD.Based on the results, we confirmed associations between two of the three novel pediatric-CD loci and other regions reported for associations with either pediatric and/or adult-onset CD.

Prevalence of spondylolisthesis in a population of gymnasts.

Spondylolysis occurs in 6 % of the general population. Of these, approximately 75% will develop spondylolisthesis. According to multiple studies, an increased prevalence of spondylolysis and spondylolisthesis exists in groups of athletes practicing certain sports such as gymnastics. In the literature, prevalence of spondylolisthesis in gymnasts can reach up to 40 to 50 %. However, the specific risk factors associated with the development of spondylolisthesis in gymnasts are not known. The main purpose of this study was to evaluate the prevalence of spondylolysis and spondylolisthesis in a population of gymnasts, as well as the associated epidemiological characteristics. In order to achieve this goal, we presented our project to the two most renowned gymnastics centers in the city of Montreal, which allowed us to recruit a total of 93 gymnasts (19 males and 74 females). A radiological evaluation, with the low emission radiographic system, EOS, allowed us to identify the subjects that were affected by spondylolysis and spondylolisthesis. Additionally, standardized questionnaires allowed us to evaluate and compare different epidemiologic parameters such as age, height, weight, number of years of practice, number of hours of training per week. Of the 93 gymnasts evaluated clinically and radiographically, we identified 6 (1 male, 5 females) gymnasts presenting a spondylolysis and/or spondylolisthesis. This 6.5% prevalence found in our population is similar to the one reported in the general population. Gender did not seem to be a determinant factor. Also, gymnasts with and without spondylolysis and/or spondylolisthesis seemed to be similar in terms of height. However, gymnasts with spondylolysis and/or spondylolisthesis seemed to be heavier than gymnasts without one of these two affections, older and training with greater intensity. These results suggest that the real prevalence rate of spondylolysis and spondylolisthesis in gymnasts may have been overestimated in previous studies. A selection bias, due to the high competitive level in the two gymnastics centers where our recruitment took place, could be involved. Our findings could also be the result of new or different training methods compared to those used in past studies. This might suggest that with intense training schedules, heavier individuals could potentially be prone to increased loads at the lumbosacral junction, thus favoring the development of spondylolysis and spondylolisthesis. These hypotheses should be explored in further details in the near future, especially with investigation of radiological parameters of the spine and pelvis.

Convolutional Neural Networks for Automatic Risser Stage Assessment.

PURPOSE: To develop an automatic method for the assessment of the Risser stage using deep learning that could be used in the management panel of adolescent idiopathic scoliosis (AIS). MATERIALS AND METHODS: In this institutional review board approved-study, a total of 1830 posteroanterior radiographs of patients with AIS (age range, 10-18 years, 70% female) were collected retrospectively and graded manually by six trained readers using the United States Risser staging system. Each radiograph was preprocessed and cropped to include the entire pelvic region. A convolutional neural network was trained to automatically grade conventional radiographs according to the Risser classification. The network was then validated by comparing its accuracy against the interobserver variability of six trained graders from the authors' institution using the Fleiss κ statistical measure. RESULTS: Overall agreement between the six observers was fair, with a κ coefficient of 0.65 for the experienced graders and agreement of 74.5%. The automatic grading method obtained a κ coefficient of 0.72, which is a substantial agreement with the ground truth, and an overall accuracy of 78.0%. CONCLUSION: The high accuracy of the model presented here compared with human readers suggests that this work may provide a new method for standardization of Risser grading. The model could assist physicians with the task, as well as provide additional insights in the assessment of bone maturity based on radiographs.© RSNA, 2020.

Investigation of reported associations between the 20q13 and 21q22 loci and pediatric-onset Crohn's disease in Canadian children.

OBJECTIVES: A recent pediatric-focused genome-wide association study has reported novel associations of the 20q13 and 21q22 loci with inflammatory bowel disease (IBD). We aimed to investigate these associations with Crohn's disease (CD) in Canadian children. METHODS: A combined case-control and case-parent design was implemented at three pediatric gastroenterology clinics in Canada. Children less than 20 years of age with a confirmed diagnosis of CD were recruited along with controls. For a subset of the patients, biological parents were also recruited. Three single-nucleotide polymorphisms (SNPs) at the 20q13 locus and 1 SNP at the 21q22 locus were genotyped. Associations between individual SNPs and haplotypes were examined. RESULTS: A total of 410 cases, 415 controls, and 302 parents were studied. The mean (+/-s.d.) age for the cases was 12.3 (+/-3.2) years. Most cases were men (56.1%) who had ileocolonic disease (L3+/-L4, 52.2%) and inflammatory behavior (B1+/-B4, 87.0%) at diagnosis. Single SNP analysis showed that all 3 SNPs at the 20q13 locus were significantly associated with CD (rs2297441, P=2.24x10(-4); rs2315008, P=4.77x10(-4); rs4809330, P=6.08x10(-3)). Haplotype analysis suggested that the association signal at 20q13 resided on a common haplotype comprising the minor allele of rs2297441 (P=2.8x10(-5)). SNP rs2836878 at the 21q22 locus showed a trend for association with CD that was statistically not significant (P=0.06). CONCLUSIONS: Our results support an association between the 20q13 locus and CD in Canadian children. Positional cloning studies are required to further dissect the potential causative genes in the region.