Adherence to Wide-Abduction Brace Treatment is Associated With Improved Hip Abduction and Radiographic Outcomes in Legg-Calvé-Perthes Disease.

INTRODUCTION: The wide-abduction A-frame brace contains the femoral head to improve its remodeling in Legg-Calvé-Perthes disease (LCPD). There is no study of the effect of brace adherence on hip outcomes. The purpose of this study was to determine if patient adherence to A-frame brace treatment is associated with improved hip abduction range of motion and radiographic outcomes in children with LCPD. METHODS: This retrospective study included patients aged 4 to 11 years with LCPD treated with an A-frame brace. Patients aged >11 and those treated with osteotomy before completing brace treatment were excluded. Built-in temperature sensors measured brace wear. Hip abduction was measured on examination before and after bracing. Deformity index (DI) and sphericity deviation score (SDS) were measured from radiographs at the 2-year follow-up and healed stage, respectively. Pearson correlation and multiple regression analyses were performed. RESULTS: Fifty-seven patients (44 male; 77%) were included with a mean age of 7.0±1.6 at brace treatment and mean adherence of 0.66±0.28. Brace adherence was associated with increased hip abduction ( R =0.36; P =0.006) and decreased DI ( R =-0.37; P =0.042) across all patients, and decreased SDS in patients <9 years old at the time of brace treatment ( R =-0.58; P =0.024). A +0.50 increase in adherence was associated with +9.4° hip abduction ( P =0.018), -0.13 DI ( P =0.027), and -17.7 SDS ( P =0.019). CONCLUSIONS: Adherence to A-frame brace treatment was associated with increased hip abduction, decreased femoral head deformity, and increased sphericity. Patients and parents can be counseled regarding brace adherence to maximize outcomes of treatment. LEVEL OF EVIDENCE: III-Therapeutic Study.

The Difference in Tibial Tuberosity to Trochlear Groove Distance Between CT and MRI Arises From the Degree of Knee Flexion During Imaging.

BACKGROUND: Tibial tuberosity to trochlear groove distance (TT-TG) has been reported to have different values according to imaging modalities, usually higher in computed tomography (CT) than in magnetic resonance imaging (MRI). This difference is thought to be caused by the degree of knee flexion during imaging, but few studies have aimed to elucidate the cause. METHODS: Five hundred eight patients with knee CT or MRI performed between ages of 6 to 16 years without underlying diseases affecting the musculoskeletal system were included. This study was conducted in 2 statistical ways. (1) Propensity score matching was performed for the imaging modality, and the bony TT-TG was compared between the 2 matched groups. (2) A regression model was fitted with 484 patients with either CT or MRI (a training set), and validation of the fitted model was performed with 24 patients with both CT and MRI simultaneously taken within a week (a test set). The predicted TT-TG values were compared with the measured values. RESULTS: (1) Eighty-one patients were successfully matched by propensity score (all the standardized mean differences < 0.1) for each modality. In the matched patients, there was no significant difference in TT-TG according to the imaging modality (11.3 ± 3.7 mm for CT, 10.4 ± 3.8 mm for MRI, P = 0.126). (2) For the model fitting, different linear models were fitted before and after 10 degrees of knee flexion angle because there was a sharp change in TT-TG when the knee flexion angle was <10 degrees. The predicted TT-TG values did not significantly differ from the measured values (10.2 ± 4.3 mm vs. 9.0 ± 5.1 mm, P = 0.124). CONCLUSIONS: This study is the first to statistically prove that the difference between TT-TG in MRI and CT originates from the different degrees of knee flexion. In addition, although more studies are needed, authors recommend imaging to be performed with the knee flexed at least 10 degrees for more reliable measurements because TT-TG changes sharply if the knee flexion angle is <10 degrees. LEVEL OF EVIDENCE: III.

Reliability of the Modified Method for Sphericity Deviation Score Using Only the Involved Hip Radiographs in the Patients With Legg-Calve-Perthes Disease.

BACKGROUND: The sphericity deviation score (SDS) is a validated radiographic outcome measure that quantifies the severity of the femoral head deformity in the healed stage of Legg-Calve-Perthes disease (LCPD). The current method requires radiographs of both hips regardless of unilateral involvement to standardize radiographic magnification. As LCPD affects the unilateral hip in 85% to 90% of cases, the current method imposes unnecessary radiation exposure to most of the patients and having to exclude patients from research studies who only had unilateral hip radiographs. We thus modified the SDS method to use unilateral hip radiographs. The purpose of this study was to investigate the reliability of the modified SDS method using the radiographs containing only one hip. METHODS: This retrospective study involved 40 patients with LCPD with unilateral involvement in the healed stage of LCPD. We modified the SDS measurement method by using the distance between the teardrop and the lateral acetabulum for magnification correction and providing a clear anatomic description of reference points on the femoral head. Three independent observers performed measurements using radiographs containing the affected hip only (modified method) and both hips (conventional method). The intraclass correlation (ICC) estimates were calculated. To verify clinical relevance, the correlation of the SDS with the Stulberg classification and hip range of motion (ROM) were also investigated. RESULTS: Measurements using the modified SDS showed excellent inter-/intra-observer ICCs (0.903 to 0.978). The ICCs between the modified and conventional methods were also excellent: 0.940 to 0.966 within the same observer and 0.897 to 0.919 between different observers. The modified SDS showed moderate-to-strong correlations with the Stulberg classification (Spearman ρ=0.650) and hip ROM (Pearson r =-0.661). CONCLUSION: The modified SDS measurement method showed excellent inter-/intra-observer reliability and moderate-to-strong correlations with the Stulberg classification and hip ROM. This method will help reduce unnecessary radiation exposure in patients with unilateral LCPD and prevent the exclusion of patients with unilateral radiographs from future research studies. LEVEL OF EVIDENCE: Level III-diagnostic study.

Injury-mechanism directness as a key factor for fracture laterality in pediatric extremity fractures.

BACKGROUND: Associations between certain extremity fracture sites and laterality in pediatric trauma are well known, whereas the rationale for such laterality tendencies are unclear. We hypothesized that the laterality tendency of a specific fracture would be affected by directness of injury mechanism and not by the fracture site itself. METHODS: We retrospectively enrolled 1382 children (aged 2-16 years) who were diagnosed with extremity fractures sustained during loss-of-balance situations and investigated the laterality tendencies (dominant vs. non-dominant extremity) of specific fracture sites. Multivariate analyses were sequentially performed to adjust for potential confounding variables-with and without injury-mechanism directness as a covariate. RESULTS: In the upper extremities, the non-dominant side was more prone to fractures (p < 0.001), especially of the distal supracondylar humerus, radial and/or ulnar shaft, and distal radius. In the lower extremities, the dominant side was more frequently fractured (p < 0.001), especially at the tibial shaft and distal tibia. However, the predisposing effects of specific fracture sites on fracture laterality were not statistically significant when in analysis adjusted for injury-mechanism directness as a covariate. Fracture laterality was affected by whether the injury mechanism was direct or indirect. Indirect injury to the upper extremity was strongly associated with non-dominant arm injury (odds ratio 0.686 [95% CI 0.517-0.991]; p = 0.009), whereas indirect injury to the lower extremity was strongly associated with dominant leg injury (odds ratio 2.138 [95% CI 1.444-3.165]; p < 0.001). CONCLUSIONS: Injury-mechanism directness, rather than fracture site itself, is a key factor that affects fracture laterality in pediatric extremity fractures. These findings are helpful for improving our understanding of which factors may affect fracture laterality among children.

Decellularized Bovine Pericardial Patch Loaded With Mesenchymal Stromal Cells Enhance the Mechanical Strength and Biological Healing of Large-to-Massive Rotator Cuff Tear in a Rat Model.

PURPOSE: The purpose of this study was to determine whether the addition of decellularized bovine pericardial patch loaded with mesenchymal stromal cells enhanced bone-to-tendon healing and improved the biomechanical strength of large-to-massive rotator cuff tears in a small animal model. METHODS: Adipose-derived mesenchymal stromal cells (MSCs) from rat inguinal fat were isolated, cultured, and loaded onto decellularized bovine pericardium patches. To simulate large-to-massive tears, rats were managed with free cage activity for 6 weeks after tear creation. A total of 18 rats were randomly allocated to repair-only (control), repair with pericardial patch augmentation (patch), or repair with MSC loaded pericardial patch augmentation (patch-MSC). Each group had 6 rats (one shoulder of each rat was used for histological evaluation and another for biomechanical evaluation). MSCs seeded on the pericardial patches were traced on four shoulders from 2 other rats at 4 weeks after surgery. Histological evaluation for bone-to-tendon healing and biomechanical testing was carried out at 8 weeks after repair. RESULTS: MSCs tagged with a green fluorescent protein were observed in the repair site 4 weeks after the repair. One shoulder each in the control and patch groups showed complete discontinuity between the bone and tendon. One shoulder in the control group showed attenuation with only a tenuous connection. Fibrocartilage and tidemark formation at the bone-to-tendon interface (P = .002) and collagen fiber density (P = .040) and orientation (P = .003) were better in the patch-MSC group than in the control or patch group. Load-to-failure in the patch-MSC and patch groups was higher than that in the control group (P = .001 and .009, respectively). CONCLUSION: Decellularized bovine pericardial patches loaded with adipose-derived and cultured mesenchymal stromal cells enhanced healing in terms of both histology and mechanical strength at 8 weeks following rotator cuff repair in a rat model. CLINICAL RELEVANCE: Large-to-massive rotator tears need a strategy to prevent retear and enhance healing. The addition of decellularized bovine pericardial patch loaded with MSCs can enhance bone-to-tendon healing and improve biomechanical healing of large-to-massive rotator cuff tears following repair.

Analysis of Tertiary Hospital Utilization in Pediatric Orthopaedics: a Study Using Nationwide Sample Data from Korea.

BACKGROUND: In the Korean medical system, the severity classification for a specific disease depends primarily on its nationwide admission rate in tertiary hospitals. Inversely, one of the important designation criteria for a tertiary hospital is the hospital's treatment ratio of patients classified as having a specific severe disease. Most diseases requiring pediatric orthopaedic surgery (POS) are not currently classified as high severity in terms of disease severity. We investigated the admission rates for the representative POS diseases in tertiary hospitals and compared these rates with those for adult orthopaedic surgery (AOS) diseases. METHODS: Seven POS diagnoses and three AOS diagnoses were selected based on frequency of admission. Nationwide sample data were used to investigate the admission rates for these representative diagnoses from 2008 to 2017. RESULTS: Six of the seven frequent POS diagnoses presented high admission rates in tertiary hospitals (62.5-92.3%). In contrast, all frequent AOS diagnoses presented low admission rates in tertiary hospitals. CONCLUSION: The admission rates of frequent POS diagnoses in tertiary hospitals are high. Considering that these rates are the most important factors for the classification of disease severity, POS diseases seem to be underestimated in terms of severity. This may lead to a tendency for tertiary hospitals to intentionally reduce the admission of children with POS diseases. As a result, these children may not receive appropriate professional care. Therefore, for the disease severity, POS diseases should be classified differently from general AOS diseases by using different criteria reflecting the patient's age.

Classification of Middle Phalangeal Postaxial Polysyndactyly Based on Intraoperative Arthrography Is Useful for Surgical Decision-making in Children Younger Than 2 Years.

BACKGROUND: The middle phalangeal type of postaxial polysyndactyly (MPPP) of the foot is a common congenital limb anomaly and is usually treated surgically at a young age. Owing to the insufficiency of radiologic evaluation due to largely cartilaginous portions of the pediatric foot, we performed intraoperative arthrography (IOA) for MPPP. This study was aimed at presenting a new classification system for foot MPPP in young children based on IOA findings and investigating its intraoperative decision-making. METHODS: Thirty-seven patients aged below 2 years who underwent IOA and surgical treatment of foot MPPP in our institute between January 2018 and April 2020 were retrospectively reviewed. The mean patient age at operation was 1.31 years (range, 0.91 to 1.99 y). IOA was performed in the common proximal interphalangeal (PIP) joint. The excisional level and side were determined on the basis of the IOA findings and bony alignment between the proximal and distal phalanges for functional and cosmetic purposes. Arthrographic findings and surgical procedures were recorded. RESULTS: A new classification divided MPPP into 2 major types according to the presence (type A) or absence (type B) of longitudinal contrast filling between the fifth and sixth middle phalanges. These 2 major types were further divided into 4 subtypes according to the shape of the PIP joint by contrast filling. There were 19, 15, and 3 cases of type A, B, and indeterminate IOA. Fifth and sixth ray excisions were performed in 26 and 11 cases, respectively. Interobserver reliability of the classification represented excellent agreement (Cohen κ coefficient=0.823). CONCLUSIONS: Our new classification based on IOA helped determine the articular dominance and its detailed morphology, which can help predict postoperative stability and mobility of the remaining toe. IOA is a simple, safe, and useful imaging tool for the surgical treatment of foot MPPP in patients aged below 2 years. LEVEL OF EVIDENCE: Level III.

Physeal Abnormalities in Children With High-risk Neuroblastoma Intensively Treated With/Without 13-Cis-Retinoic Acid.

BACKGROUND: This study aimed to investigate the presence of physeal abnormality and its effect on growth in children with high-risk neuroblastoma treated by intensive multimodal treatment with/without 13-cis-retinoic acid (13-CRA). METHODS: Fifteen patients diagnosed with high-risk neuroblastomas at the age of 1 to 10 years, who received treatment such as high-dose chemotherapy and autologous stem cell transplantation with/without 13-CRA, and with complete data during their >2-year follow-up were retrospectively reviewed. The physeal abnormalities were investigated by whole-body magnetic resonance imaging, serially performed every 3 to 6 months. The patients' height growth was also investigated and compared with that of age-and-sex-matched patients with brain tumors who also underwent high-dose chemotherapy and autologous stem cell transplantation. RESULTS: Six of 15 patients presented multifocal physeal abnormalities during follow-up, and all lesions occurred in patients with 13-CRA use. The lesions in 3 patients completely resolved spontaneously without any adverse effect on growth, but some lesions in the other 3 patients progressed to disturb the bony growth. Height growth of matched patients with brain tumors were not significantly different, and none of the matched controls showed definite bony deformity during the follow-up. CONCLUSIONS: Some children who were treated for high-risk neuroblastomas experienced multifocal physeal insults, probably due to the use of 13-CRA. Most lesions resolved spontaneously, but some led to bony deformity. If the lesions are not followed by premature physeal closure, there seems to be no further adverse effect of 13-CRA on leg length growth. Routine periodic screening for physeal status is needed for the patients with high-risk neuroblastomas using 13-CRA. LEVEL OF EVIDENCE: Level IV-prognostic study.

Prediction of High-Grade Hip Joint Effusion With Simple Radiographs in Children: A Comparative Study With Magnetic Resonance Imaging.

OBJECTIVES: The objective of this study was to investigate the predictive value of asymmetric joint space widening on simple radiographs for the presence of hip joint effusion in children with unilateral hip pain. METHODS: Sixty-eight patients aged 6 to 17 years with both simple radiograph and magnetic resonance imaging of both hips were retrospectively reviewed. We evaluated the predictive effects of radiographic surrogates for joint space widening on the presence of high-grade hip joint effusion. We also sought to investigate a predictive model for the presence of hip joint effusion with the patients' clinical and radiological data. RESULTS: Radiographic values showed high specificity but low sensitivity for the presence of high-grade joint effusion. On multivariate analysis, sex and the difference ratio of medial and superior gaps were independent predictive factors for unilateral high-grade hip joint effusion. CONCLUSIONS: For children 6 years and older with asymmetric hip joint space widening on simple radiographs, further evaluations for the presence of hip joint effusion should be considered because of its high specificity. The predictability can improve if both medial and superior gaps, and sex are included in the evaluation. In girls, hip joint effusion seems to widen the joint space more easily than in boys, which may be owing to the more ligamentous laxity of and less musculature around the hip in girls. However, the risk of joint effusion should not be underestimated even if a child presents symmetry on the simple radiograph because of its low sensitivity and the possibility of bilateral involvements or early stage of diseases.

Agreement of Postoperative Pain Assessment by Parents and Clinicians in Children Undergoing Orthopedic Surgery.

BACKGROUND: Postoperative pain assessment in children is crucial for proper nursing care. However, research on the agreement of these assessments with a patient's self-reported pain level is lacking. The aim was to investigate the agreement between patients' subjective postoperative pain and corresponding observers' pain assessments. METHODS: In children who underwent orthopedic limb surgery, we investigated the agreement between their reported pain levels and observers' pain assessments using the Numeric Pain Rating Scale (NPRS) and the Faces Pain Scale-Revised (FPS-R) on postoperative day 1. The parents (specifically the mother) and clinicians (a doctor and a nurse in the field of pediatric orthopedics) participated as observers. Reliabilities using intraclass correlation coefficients (ICCs) and correlations using Spearman's coefficients (rs) were calculated. RESULTS: The patients' pain intensities (2.1± 2.1 [NPRS] and 2.0 ± 1.9 [FPS-R]) were overestimated by parents (2.5 ± 2.0 [NPRS], p = .022), but underestimated by clinicians (1.5 ± 1.2 [NPRS], p < .001, and 1.5 ± 1.2 [FPS-R], p = .006). The overall reliabilities between parents and patients were good (ICCs > 0.75 for both NPRS and FPS-R), and the correlations between them were even strong in some circumstances, such as when the patient was a girl, the diagnostic type was a disease, or the lower extremity was operated (rss > 0.7). However, the agreements between clinicians and patients were only moderate. CONCLUSIONS: The subjective pediatric postoperative pain intensities had different agreements according to the observers. The parents' assessments should be considered for the accurate assessments, but their tendency to overestimate their children's pain should also be taken into account.

Prediction of the Peripheral Rim Instability of the Discoid Lateral Meniscus in Children by Using Preoperative Clinicoradiological Factors.

BACKGROUND: The discoid lateral meniscus (DLM) in children often presents peripheral rim instability (PRI) and is susceptible to tear or subluxation, which manifests symptoms and leads to a poor prognosis. We aimed to investigate the association between preoperative clinical and MRI findings and the intraoperative findings of PRI. METHODS: Children and adolescents aged younger than 16 years who underwent surgical treatment for DLM were retrospectively reviewed. Cases of bucket-handle tear were not included because they would confound the stability of the peripheral rim. Total 60 knees from 47 children were included. PRI was additionally subdivided based on the location, such as anterior, middle, and posterior, during the investigation. RESULTS: In multivariate analyses, both central (inward) (P=0.004) and external (outward) (P=0.029) displacement of lateral meniscal margin, and peripheral tear of the anterior body (P=0.022) were significant predictors of PRI, regardless of the location. The predictive factors for PRI based on each location were female gender (P=0.004), subjective symptom of clicking sound (P=0.023), and central displacement of the anterior meniscal margin (P=0.034) for anterior PRI; flexion contracture >10 degrees (P=0.017) and peripheral tear of the middle body (P<0.001) for middle PRI; and central displacement of the posterior meniscal margin (P=0.036) and peripheral tears of the anterior (P=0.029) and middle bodies (P=0.047) for posterior PRI. CONCLUSIONS: We evaluated the preoperative clinical and MRI findings that predict PRI of pediatric DLM. Displacements of the DLM, not only centrally (inward) but also externally (outward), seem to be significant predictive factors for PRI. Furthermore, some clinical findings were associated with PRI, even predicting the locations. Although the actual surgical procedure should be determined by meticulous probing during arthroscopy, preoperative prediction of the presence and location of PRI would help decrease the risk of oversight during surgery. LEVEL OF EVIDENCE: Level III-Diagnostic Study.

Early-Stage Femoral Head Hypoperfusion Correlates with Femoral Head Deformity at Intermediate Follow-up in Legg-Calvé-Perthes Disease.

BACKGROUND: Perfusion MRI (pMRI) can quantify femoral head hypoperfusion in early-stage Legg-Calvé-Perthes disease. We investigated whether the severity of hypoperfusion measured at the early stage correlates with femoral head deformity at intermediate-term follow-up. METHODS: Sixty-three patients who were 5 to 11 years of age at the diagnosis of Legg-Calvé-Perthes disease and who had pMRI performed at an early stage (Waldenström Stage 1 to 2a) were retrospectively reviewed. Twenty-eight patients were treated nonoperatively and 35 were treated with proximal femoral varus osteotomy (PFVO). The sphericity deviation score (SDS) was used as the primary outcome. Femoral head perfusion and SDS were measured by 2 observers. Models assessing the relationship between hypoperfusion and SDS were fitted without and with stratifications by age at diagnosis and treatment method. RESULTS: All 63 patients had a minimum of 4 years of follow-up (mean follow-up, 7.5 ± 2.6 years). All had reached the healed stage (Stage 4), and their mean age was 15.6 ± 2.8 years. The SDS outcome showed a significant positive correlation with the hypoperfusion % (p < 0.001). In the <50% hypoperfusion range, the SDS indicated no-to-low deformity, with narrow variability of outcome. However, the SDS became exponentially worse and had a wider variability of outcome at the ≥50% hypoperfusion range. Multivariable analyses revealed age at diagnosis, hypoperfusion %, and treatment method as significant prognostic factors for SDS (p = 0.007, <0.001, and 0.042, respectively). When treatment outcomes were stratified by age at diagnosis and hypoperfusion %, PFVO showed significantly better SDS outcome than nonoperative treatment in patients with an age at diagnosis of ≥8 years and low (<50%) and intermediate (50% to 80%) hypoperfusion ranges (p = 0.036 and 0.021, respectively). CONCLUSIONS: Our study found a significant relationship between femoral head hypoperfusion measured in early-stage Legg-Calvé-Perthes disease and femoral head deformity at intermediate-term follow-up. This study provides new insight into the relationship between early-stage femoral head hypoperfusion and deformity. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Protocol for extracting and isolating porcine bone-marrow-derived macrophages from ribs.

Due to anatomical and biological similarities with humans, pigs are increasingly used for inflammation- and immune-related studies in biomedical research, including the field of osteonecrosis and osteoimmunology. Here, we present a protocol for rib extraction, isolation of the bone marrow by centrifugation, and processing to obtain bone-marrow-derived macrophages (BMDMs). Then, we describe the procedures of in vitro experiments to evaluate the cell phenotype. For complete details on the use and execution of this protocol, please refer to Andre et al.1.

Postoperative Calcaneocuboid Joint Subluxation and Midtarsal Joint Changes in Pediatric Idiopathic Flexible Flatfoot Treated With Calcaneal Lengthening Osteotomy: A Midterm Follow-up Study.

BACKGROUND: Calcaneal lengthening osteotomy (CLO) is one of the main surgical options for treatment of pediatric idiopathic flexible flatfoot (FFF). Reportedly, calcaneocuboid (CC) joint subluxation occurs after CLO; however, its effect on the midfoot remains unclear. This study aimed to investigate the radiologic midterm results after CLO treatment in pediatric idiopathic FFF. METHODS: We evaluated 23 pediatric patients with idiopathic FFF aged ≥8 years, who underwent CLO from 1999 to 2017 owing to moderate to severe flatfoot deformity (assessed by visual inspection). Patients aged between 8 and 14 years were included (mean follow-up: 6.3 years; range, 3.1-11.4 years). Anteroposterior and lateral weightbearing foot radiographs were assessed for radiologic parameters preoperatively and at the 3-month, 1-year, and final follow-ups postoperatively. RESULTS: All patients had immediate postoperative radiologic correction of the flatfoot deformity, and these improvements were maintained until the final follow-up. The mean allograft length inserted was 9 (range, 8-10) mm. There was increased CC joint subluxation after CLO, but it improved continuously until the final follow-up. A CC joint spur was newly noted in 1 case. There were 24 cases (24/39, 61.5%) of talonavicular (TN) joint spurs at the final follow-up, but 19 of these were already present on the preoperative radiographs (19/24, 79.2%). Further, the new-onset TN joint spurs were not associated with preoperative clinicoradiologic factors. CONCLUSION: In pediatric patients with idiopathic FFF receiving CLO treatment, preoperative radiologic angles improved. CC joint subluxation increased after surgery; however, it gradually reduced without evidence of CC joint arthritic changes over the time period studied in this cohort.

[Impact of social distancing on traumatic injury incidence during the COVID-19 pandemic: A study using nationwide data from South Korea from 2018 to 2020.] / Impact de la distanciation sociale sur l'incidence lésions traumatiques pendant la pandémie de COVID-19 : étude utilisant des données nationales de la Corée du Sud de 2018 à 2020.

BACKGROUND: COVID-19 spread rapidly in 2020. To decrease its transmission rate, governments worldwide implemented social distancing. It has transformed people's physical and social activities. Such changes, differently influenced by age, might affect the incidence of traumatic injury. HYPOTHESIS: The impact of social distancing on traumatic injuries can influence differently by age. PATIENTS AND METHODS: Nationwide randomized stratified sampling data (2018 to 2020, 1 million people per year) from Korean National Health Insurance Sharing Service were used. In this period, 364,690 patients with traumatic injuries were analyzed. People were grouped by age into 0 - 4, 5 - 19, 20 - 64, and ≥ 65 years. The incidence of traumatic injuries was compared between periods of social distancing and no social distancing. Social distancing levels, injured body parts, injury types, hospitalization rate, total medical cost per patient, weather, temperature, and holidays were also included for detailed analysis. RESULTS: Only the 5-19 age group showed the significant interaction of social distancing and traumatic injury. In this group, as the social distancing level increased, the injury incidence decreased especially during the spring and autumn semesters. However, the proportion of injuries requiring hospitalization and total medical cost per patient increased. DISCUSSION: Social distancing significantly affects the incidence of traumatic injuries for schooler (5 - 19 years). Considering that the incidence changed during these semesters, the restriction of school attendance, due to social distancing, may have caused the decrease. Reduced trauma in this group seems to be related to decrease of mild trauma, considering the hospitalization rate and total medical costs. LEVEL OF EVIDENCE: III, retrospective cohort study.

Impact of social distancing on traumatic injury incidence during the COVID-19 pandemic: A study using nationwide data from South Korea from 2018 to 2020.

BACKGROUND: COVID-19 spread rapidly in 2020. To decrease its transmission rate, governments worldwide implemented social distancing. It has transformed people's physical and social activities. Such changes, differently influenced by age, might affect the incidence of traumatic injury. HYPOTHESIS: The impact of social distancing on traumatic injuries can influence differently by age. PATIENTS AND METHODS: Nationwide randomized stratified sampling data (2018 to 2020, 1 million people per year) from Korean National Health Insurance Sharing Service were used. In this period, 364,690 patients with traumatic injuries were analyzed. People were grouped by age into 0-4, 5-19, 20-64, and≥65years. The incidence of traumatic injuries was compared between periods of social distancing and no social distancing. Social distancing levels, injured body parts, injury types, hospitalization rate, total medical cost per patient, weather, temperature, and holidays were also included for detailed analysis. RESULTS: Only the 5-19 age group showed the significant interaction of social distancing and traumatic injury. In this group, as the social distancing level increased, the injury incidence decreased especially during the spring and autumn semesters. However, the proportion of injuries requiring hospitalization and total medical cost per patient increased. DISCUSSION: Social distancing significantly affects the incidence of traumatic injuries for schooler (5-19years). Considering that the incidence changed during these semesters, the restriction of school attendance, due to social distancing, may have caused the decrease. Reduced trauma in this group seems to be related to decrease of mild trauma, considering the hospitalization rate and total medical costs. LEVEL OF EVIDENCE: III, retrospective cohort study.

Overlooked valgus bowing deformity in pediatric tibial shaft fractures with/without fibular involvement: Cause residual valgus alignment in 2-year follow-up.

BACKGROUND: Children with a tibial shaft fracture often present with valgus malalignment, even when anatomical reduction had been achieved at the fracture site. Pediatric bony structure has more elastic bones than that of adults, it can cause bowing deformity. Therefore, we evaluated pediatric tibial shaft fracture for the presence of bowing deformity, associated risk factors, and its clinical significance. HYPOTHESIS: There is an overlooked bowing deformity in pediatric tibial shaft fracture. PATIENTS AND METHODS: Fifty-seven tibial shaft fracture patients aged 2 to 15 years with Risser stage 0 were retrospectively reviewed. Clinicoradiologic factors and radiographs taken within 3 post-traumatic months and at 2 years were assessed. To evaluate the tibial bowing deformity, the tibial interphyseal angle and tibial shaft angle were measured, and their differences were calculated as a tibial bowing angle. RESULTS: Multivariate analysis revealed the tibial shaft fracture with fibular involvement is significantly associated with a higher initial tibial bowing angle (valgus deformity). The tibial bowing angle did not change over 2-year follow-up. A high initial tibial bowing angle (≥ 5°) was a significant risk factor for the persistence of valgus malalignment. DISCUSSION: Pediatric tibial shaft fractures with/without fibular involvement carry the risk of valgus bowing deformity, which may not develop during post-traumatic growth but may be present at the time of injury. The risk is high if the tibial fracture is accompanied by a fibular fracture. This tibial deformity presents limited remodeling potential at 2-year follow-up. LEVEL OF EVIDENCE: IV; retrospective study.

Ogden Type IV Tibial Tuberosity Fractures in Healthy Adolescents: Preoperative Magnetic Resonance Imaging and 2-Year Clinical Follow-up Study.

Background: Ogden type IV tibial tuberosity fractures, defined as a type of fracture with posterior-inferior metaphyseal extension (Salter-Harris type II variant), are uncommon but challenging pediatric fractures. The purpose of this study was to investigate the clinical and radiological presentation and associated surgical outcomes. Methods: Ten previously healthy patients who had been surgically treated at the authors' institution between 2015 and 2018 with at least 2 years of postoperative follow-up were included. Demographic, clinical, and radiological characteristics and treatment/follow-up data were investigated. Results: All included patients were male. All injuries resulted from jump-landings. Unacceptable remaining angular deformity after closed reduction, particularly increased posterior tibial slope angle, was the leading cause of surgery. All preoperative magnetic resonance images (MRIs) showed entrapped periosteum on the anteromedial side of the proximal tibial physis. Surgical removal of the entrapped periosteum achieved successful reduction. Metaphyseal fracture angles between the fracture plane of the metaphyseal beak and the posterior tibial condyle on the axial image of MRI were relatively constant, with an average of 24.3° ± 6.0°. Mean bone age at the time of trauma was older than mean chronological age (16.4 ± 1.0 years vs. 14.6 ± 1.1 years, respectively; p = 0.005). All patients reached skeletal maturity within 2 postoperative years, with little posttraumatic residual height growth (mean, 1.6 ± 0.7 cm from injury to skeletal maturity). At final follow-up, no patients showed significant angular deformity, tibial length discrepancy, or functional deficit. Conclusions: In healthy adolescents, Ogden type IV tibial tuberosity fractures typically occur by jump-landing injuries, when they have little residual growth remaining. Therefore, accurate fracture reduction was required because of limited remodeling potential. Patients with unacceptable reduction should be investigated for entrapped periosteum on the anteromedial side of the physis because it was the primary obstacle in achieving adequate reduction.

Clinico-radiological factors predicting the failure risk of conservative management in moderate to severe pediatric idiopathic flexible flatfoot.

This study aimed to investigate the clinico-radiological factors of related future surgical treatment in patients with pediatric flexible flatfoot (FFF) who first visited the orthopedic clinic before the age of 10 years. Sixty-five patients diagnosed with moderate/severe idiopathic FFF deformity between the ages of 2-10 years were included. We developed prognostic models for the risk of the surgery during the follow-up period. Twenty (30.8%) patients required surgical treatment, and all of them underwent calcaneal lengthening osteotomy. Among them, 7 (10.8%) patients required concomitant Achilles-lengthening surgery. Unilateral involvement, older age, smaller calcaneal pitch angle, and higher talo-first metatarsal malalignment were considered high-risk factors for pediatric FFF surgery. Prognostic models identified three prognostic risk groups based on those factors, and survival curves revealed significant differences among the groups. Our prognostic models help predict the failure risk of conservative management of pediatric idiopathic FFF. Level of Evidence: Level III, prognostic study.

Injury Characteristics and Predisposing Effects of Various Outdoor Traumatic Situations in Children and Adolescents.

BACKGROUD: Many studies have reported injury characteristics of individual traumatic situations. However, a comparative analysis of specific risks is meaningful to better understand injury characteristics and help establish injury-prevention measures. This study was conducted to investigate and compare injury characteristics in children and adolescents by various outdoor traumatic situations. METHODS: Outdoor traumatic situations were determined and classified into physical activity-related injury (n = 3,983) and pedestrian (n = 784) and passenger (n = 1,757) injuries in traffic accidents. Home injury (n = 16,121) was used as the control group. Then, the characteristics of each outdoor trauma were compared with 1:1 matched indoor trauma (among home injuries); each outdoor traumatic situation's predisposing risk for the injured body part, injury type, and injury severity were analyzed; and changes by age of frequency ranking among physical activity-related injuries were investigated. RESULTS: Outdoor trauma showed higher risks for limb injuries (injured body part), fracture and muscle/tendon injuries (injury type), and severe injuries (severity) than indoor trauma. Various outdoor traumatic situations presented different predisposing effects on injury characteristics. Among physical activity-related injuries, bicycle injury was commonest across all ages, and playing activities were common causes for injury for individuals of age < 9 years, whereas sports activities overwhelmed the common causes thereafter. CONCLUSIONS: The findings would help to better understand the specific injury risk of various outdoor traumatic situations and may potentially facilitate the establishment of more effective injury-prevention measures.