Pediatric Bone Imaging: Imaging Elbow Trauma in Children???A Review of Acute and Chronic Injuries

The efficacy of pediatric elbow radiographic guidance in diagnosis of lateral humeral condyle fracture

Although lateral humeral condyle fracture is common, the incidence of missed diagnosis is very high. Delayed and missed diagnosis led to significant morbidities and loss of functions. We designed a pediatric elbow radiographic guidance aiming to improve the accuracy of diagnosis. This study was aimed to evaluate the efficacy of the radiographic guidance for the diagnosis of lateral condyle fracture. A cross-sectional study was conducted after defining the essential parameters as a guidance for assessing the pediatric elbow radiographs. We included medical students, emergency medicine, orthopedic, and radiology residents and fellows into this study. A questionnaire was used to evaluate the efficacy of the guidance. All participants underwent a pretest evaluation, followed by studying the guidance, and then finished a posttest evaluation. Baseline characteristics, diagnostic scores, and parameter evaluation scores were collected. The pretest and posttest scores were analyzed using paired t-test. Association between baseline characteristics and diagnostic scores were analyzed using multiple regression analysis. We included 177 participants. Average diagnostic score was significantly increased after using the guidance, from 12.2 ± 1.9 to 13.0 ± 1.7 (p < 0.0001). Medical students showed the most improvement, from 11.9 ± 1.9 to 13.1 ± 1.3 (p <0.001). All means of essential parameter evaluation scores were significantly improved in overall participants.The pediatric elbow radiographic guidance is useful for evaluation and diagnosis of lateral condyle fracture, especially for young physicians and trainees. Therefore, this should be recommended in routine medical education and general practice.

Proximal ulna morphology in various pediatric population age groups: proximal ulna dorsal angulation (PUDA) and olecranon tip-to-apex (TTA) distance

PURPOSE

To measure proximal ulna dorsal angulation (PUDA) and olecranon tip-to-apex distance (TTA) in pediatric population to aid surgeons with data for proximal ulna fractures fixation.

METHODS

Retrospective review of the hospital radiographic database. All elbow radiographs were identified and after implementing exclusion criteria, included were 95 patients aged 0-10; 53 patients aged 11-14; and 53 patients aged 15-18. PUDA was defined as the angle between lines placed on the "flat spot" of the olecranon and the dorsal edge of the ulnar shaft and TTA as the distance between the tip of the olecranon to the apex of angulation. Two evaluators performed measurements independently.

RESULTS

In age group 0-10, mean PUDA was 7.53°, range 3.8-13.7, 95% CI 7.16-7.91, while mean TTA was 22.04 mm, range 8.8-50.5, 95% CI 19.92-24.17. In age group 11-14, mean PUDA was 4.99°, range 2.5-9.3, 95% CI (4.61-5.37), while mean TTA was 37.41 mm, range 16.5-66.6, 95% CI (34.91-39.90). In age group 15-18, mean PUDA was 5.18°, range 2.9-8.1, 95% CI (4.75-5.61), while mean TTA was 43.79 mm, range 24.5-79.4, 95% CI (41.38-46.19). PUDA was negatively correlated with age (r = - 0.56, p < 0.001), while TTA was positively correlated with age (r = 0.77, p < 0.001). Reliability levels of 0.81-1 or 0.61-0.80 were achieved for most of intra- and inter-rater reliabilities besides two levels of 0.41-60 and one of 0.21-0.40.

CONCLUSION

The main study finding is that in most cases mean age-group values may serve as a template for proximal ulna fixation. There are some cases in which X-ray of contralateral elbow may provide surgeon with a better template.

LEVEL OF EVIDENCE

II.

Deep learning accurately classifies elbow joint effusion in adult and pediatric radiographs

Joint effusion due to elbow fractures are common among adults and children. Radiography is the most commonly used imaging procedure to diagnose elbow injuries. The purpose of the study was to investigate the diagnostic accuracy of deep convolutional neural network algorithms in joint effusion classification in pediatric and adult elbow radiographs. This retrospective study consisted of a total of 4423 radiographs in a 3-year period from 2017 to 2020. Data was randomly separated into training (n = 2672), validation (n = 892) and test set (n = 859). Two models using VGG16 as the base architecture were trained with either only lateral projection or with four projections (AP, LAT and Obliques). Three radiologists evaluated joint effusion separately on the test set. Accuracy, precision, recall, specificity, F1 measure, Cohen’s kappa, and two-sided 95% confidence intervals were calculated. Mean patient age was 34.4 years (1–98) and 47% were male patients. Trained deep learning framework showed an AUC of 0.951 (95% CI 0.946–0.955) and 0.906 (95% CI 0.89–0.91) for the lateral and four projection elbow joint images in the test set, respectively. Adult and pediatric patient groups separately showed an AUC of 0.966 and 0.924, respectively. Radiologists showed an average accuracy, sensitivity, specificity, precision, F1 score, and AUC of 92.8%, 91.7%, 93.6%, 91.07%, 91.4%, and 92.6%. There were no statistically significant differences between AUC's of the deep learning model and the radiologists (p value > 0.05). The model on the lateral dataset resulted in higher AUC compared to the model with four projection datasets. Using deep learning it is possible to achieve expert level diagnostic accuracy in elbow joint effusion classification in pediatric and adult radiographs. Deep learning used in this study can classify joint effusion in radiographs and can be used in image interpretation as an aid for radiologists.

Not all that looks fractured is broken-multipartite humeral epicondyles in children

Objective

Multipartite epicondyles may mimic fractures in the setting of pediatric elbow trauma. This study examines the prevalence of multipartite epicondyles during skeletal development and their association with pediatric elbow fractures.

Materials and methods

In this retrospective analysis, 4282 elbow radiographs of 1265 elbows of 1210 patients aged 0–17 years were reviewed. The radiographs were analyzed by two radiologists in consensus reading, and the number of visible portions of the medial and lateral epicondyles was noted. For elbows in which epicondylar ossification was not yet visible, the epicondyles were already fused with the humerus or could not be sufficiently evaluated due to projection issues or because osteosynthesis material was excluded. In total, 187 elbows were included for the lateral and 715 for the medial epicondyle analyses.

Results

No multipartite medial epicondyles were found in patients without history of elbow fracture, whereas 9% of these patients had multipartite lateral epicondyles (p < 0.01). Current or previous elbow fractures increased the prevalence of multipartite epicondyles, with significant lateral predominance (medial epicondyle + 9% vs. lateral + 24%, p < 0.0001). Including all patients regardless of a history of elbow fracture, multipartite medial epicondyles were observed in 3% and multipartite lateral epicondyles in 18% (p < 0.0001). There was no gender difference in the prevalence of multipartition of either epicondyle, regardless of a trauma history.

Conclusion

Multipartite medial epicondyles occur in patients with current or previous elbow fractures only, whereas multipartite lateral epicondyles may be constitutional. Elbow fractures increase the prevalence of multipartite epicondyles on both sides, with significant lateral predominance.

Key Points

• Multipartite medial epicondyles should be considered of traumatic origin.

• Multipartite lateral epicondyles may be constitutional.

• Elbow fractures increase the prevalence of multipartite epicondyles on both sides with lateral predominance.

Understanding the susceptibility to lateral condyle fracture by analyzing unaffected Baumann's angle in children with distal humeral fracture

BACKGROUND

Previous studies have shown that posttraumatic cubitus varus deformity in children is somehow related to subsequent humeral lateral condyle fracture. Moreover, we had previously encountered an exactly similar case. In this study, we aim to understand whether there is a morphological difference between pediatric supracondylar and lateral condyle fracture of the humerus by comparing Baumann's angle of the unaffected elbow.

METHODS

We conducted a retrospective evaluation of 40 cases of supracondylar fractures (36 boys, 4 girls) and 20 cases of lateral condyle fractures (16 boys, 4 girls) at a single facility between January 2014 and December 2018. The unaffected Baumann's angles and lateral capitellohumeral angles of both groups were measured by two orthopedic surgeons and analyzed using Welch's t-test. The effect size was also calculated using Cohen's d, and intraclass correlation coefficients were applied for intra-rater and inter-rater reliability.

RESULTS

The average age of patients in the supracondylar fracture group was 6.78 years and that in the lateral condyle fracture group was 5.70 years. No significant differences were observed between gender and fracture type, between laterality and fracture type, and in the lateral capitellohumeral angles between the groups. Baumann's angle was significantly less in the lateral condyle fracture group (17.27° ± 4.68°) than in the supracondylar fracture group (20.28° ± 3.10°) as analyzed by Welch's t-test (p = 0.015). The effect size was 0.76. Each of the intra-rater reliabilities were 0.97 and 0.96, whereas the inter-rater reliability was 0.75.

CONCLUSIONS

A significant morphological difference was found between the supracondylar fracture group and the lateral condyle fracture group. The loss of Baumann's angle which tends to occur after the healing of supracondylar fracture may increase the susceptibility to lateral condyle fracture. Orthopedic surgeons should repair and fix supracondylar fractures appropriately to avoid an ipsilateral second fracture, such as lateral condyle fracture.

Accurate Instance Segmentation in Pediatric Elbow Radiographs

Radiography is an essential basis for the diagnosis of fractures. For the pediatric elbow joint diagnosis, the doctor needs to diagnose abnormalities based on the location and shape of each bone, which is a great challenge for AI algorithms when interpreting radiographs. Bone instance segmentation is an effective upstream task for automatic radiograph interpretation. Pediatric elbow bone instance segmentation is a process by which each bone is extracted separately from radiography. However, the arbitrary directions and the overlapping of bones pose issues for bone instance segmentation. In this paper, we design a detection-segmentation pipeline to tackle these problems by using rotational bounding boxes to detect bones and proposing a robust segmentation method. The proposed pipeline mainly contains three parts: (i) We use Faster R-CNN-style architecture to detect and locate bones. (ii) We adopt the Oriented Bounding Box (OBB) to improve the localizing accuracy. (iii) We design the Global-Local Fusion Segmentation Network to combine the global and local contexts of the overlapped bones. To verify the effectiveness of our proposal, we conduct experiments on our self-constructed dataset that contains 1274 well-annotated pediatric elbow radiographs. The qualitative and quantitative results indicate that the network significantly improves the performance of bone extraction. Our methodology has good potential for applying deep learning in the radiography's bone instance segmentation.

Pediatric Imaging of the Elbow: A Pictorial Review

The elbow is a complex joint, subject to a wide range of traumatic, inflammatory, metabolic and neoplastic insults. The pediatric elbow has several diagnostic pitfalls due to the normal developmental changes in children. Knowledge of these normal variants is essential for both diagnosis and management of their elbow injuries. Radiography remains the first imaging modality of choice. Magnetic resonance imaging is excellent in evaluating lesions within the bone and soft tissues. In this pictorial essay, we provide insights into pediatric elbow imaging, show a range of entities specific to the pediatric elbow, and discuss diagnostic pitfalls that result from normal elbow growth in children.

Imaging of Elbow Injuries

Familiarity with throwing mechanics during elbow range of motion allows accurate diagnosis of sports-related elbow injuries, which occur in predictable patterns. In addition, repetitive stress-related injuries are often clinically apparent; however, imaging plays an important role in determining severity as well as associated injuries that may affect clinical management. A detailed understanding of elbow imaging regarding anatomy and mechanism of injury results in prompt and precise treatment.

Uniquely pediatric upper extremity injuries

The pediatric population is prone to unique upper extremity injuries that are not typically seen in adults. The normal dynamic maturation pattern of ossification centers and open physis can potentially confuse radiologists who are not familiar with the pediatric patients. In this review article, we discuss the normal anatomy and commonly encountered acute and chronic upper extremity injuries such as supracondylar distal humeral fracture and osteochondritis dissecans, in pediatric patients. Diagnosing the correct type of fracture (e.g., buckle vs Salter-Harris) is important for proper management of the injury. With an increasing number of adolescents participating in competitive sports, specific sports related injuries such as little league shoulder, gymnast wrist, and medial epicondyle apophysitis, are also discussed in this review. We examine late complications of injuries, such as physeal bar formation and fishtail deformity of the distal humerus.

Complex Fracture-Dislocations of the Elbow in the Pediatric Population

BACKGROUND

Complex fracture-dislocations of the elbow, including terrible triad of the elbow, are serious injuries with guarded outcomes in adults. Although described extensively in adults, little is known about similar complex fracture-dislocations of the elbow in the pediatric population. The purpose of this study was to describe patterns of elbow dislocations with associated fractures in children and report the outcomes of these injuries.

METHODS

This was a retrospective review of patients who presented to a level I trauma center from 2007 to 2019 with an elbow dislocation and at least 2 associated fractures. Demographic data, fracture locations, and treatment modality were recorded. Operative reports and radiographs were reviewed to determine clinical outcomes and complications.

RESULTS

A total of 26 patients (mean age, 9.8 y) were identified. The majority of patients sustained an elbow dislocation and a medial epicondyle fracture (n=16). The most common third fractures involved the lateral condyle (n=8) or radial neck (n=7). At mean 6.03±3.11 months follow-up, 3 patients lacked ≥10 degrees of extension, and 2 patients lacked ≥15 degrees of flexion. Most patients had a Flynn score of "excellent" (n=20, 76.9%) or "good" (n=2, 7.7%). One patient with significant residual stiffness (>30 degrees flexion contracture) eventually underwent open contracture release.

CONCLUSIONS

The most common complex elbow fracture-dislocation pattern in this series was an elbow dislocation with fracture of the medial epicondyle and lateral condyle or radial neck. In contrast to adult terrible triad injuries, most patients had a favorable clinical outcome, with nearly 80% excellent results and a low rate of complications.

LEVEL OF EVIDENCE

Therapeutic Level IV-case series.

Pediatric Musculoskeletal Trauma: Upper Limb

Pediatric upper extremity injuries, acute and chronic due to overuse, are commonly encountered in the clinical setting. However, interpretation of imaging studies is often challenging in pediatric patients because of changing postnatal skeletal development and the broad spectrum of pathology that can potentially occur. This article discusses normal skeletal development and the pathomechanics of skeletal injuries in pediatric patients. It also outlines a framework for imaging as it pertains to the pediatric upper extremity, with specific emphasis on acute and chronic injuries to the shoulder, elbow, forearm, and wrist.

A think-aloud study to inform the design of radiograph interpretation practice

Models for diagnostic reasoning in radiology have been based on the observed behaviors of experienced radiologists but have not directly focused on the thought processes of novices as they improve their accuracy of image interpretation. By collecting think-aloud verbal reports, the current study was designed to investigate differences in specific thought processes between medical students (novices) as they learn and radiologists (experts), so that we can better design future instructional environments. Seven medical students and four physicians with radiology training were asked to interpret and diagnose pediatric elbow radiographs where fracture is suspected. After reporting their diagnosis of a case, they were given immediate feedback. Participants were asked to verbalize their thoughts while completing the diagnosis and while they reflected on the provided feedback. The protocol analysis of their verbalizations showed that participants used some combination of four processes to interpret the case: gestalt interpretation, purposeful search, rule application, and reasoning from a prior case. All types of processes except reasoning from a prior case were applied significantly more frequently by experts. Further, gestalt interpretation was used with higher frequency in abnormal cases while purposeful search was used more often for normal cases. Our assessment of processes could help guide the design of instructional environments with well-curated image banks and analytics to facilitate the novice's journey to expertise in image interpretation.

A Practical Method for Obtaining True Lateral Elbow X-rays in a Paediatric Age Group: Lateral Elbow X-ray in the Standing Salute Position

INTRODUCTION

Paediatric elbow fractures constitute 10% of all paediatric fractures. Radiological interpretation of the immature elbow is difficult due to its cartilaginous structure. We aimed to describe an X-ray technique in paediatric patients to obtain true lateral elbow X-rays and to prevent the repeat X-ray shots.

MATERIALS AND METHODS

Radiographs of 39 children, with a mean age of 48.17 months (range; 7-84 months), with elbow trauma were included. All elbow lateral radiographs were taken in the 90º flexion position. In the first group, radiographs were taken using the standard technique(lateral radiographs in shoulder internal rotation). In the second group, lateral radiographs of the elbow were taken while the patient was standing and the forearm was elevated passively with 90° shoulder abduction and 90° elbow flexion (standing salute position). Three criteria were examined from the graphs to determine the true lateral elbow graphy.

RESULTS

In group 1 (n = 20) and group 2 (n = 19), lateral elbow radiographs were evaluated. No statistically significant differences were found between the groups, in terms of mean age and distal humeral fractures. In group 2; the presence of humeroulnar joint space, partial coronoid superposition of the radius head and presence of the hourglass formation were significantly higher.

DISCUSSION

It is clear that radiographs taken in appropriate positions decreases diagnostic errors. In our study, the ratio of correct lateral radiographs was significantly higher in the radiograph group in the standing salute position, suggesting this method was safe for accurate lateral radiographs, in accordance with our hypothesis.

Magnetic resonance imaging of the elbow

Elbow pain can cause disability, especially in athletes, and is a common clinical complaint for both the general practitioner and the orthopaedic surgeon. Magnetic resonance imaging (MRI) is an excellent tool for the evaluation of joint pathology due to its high sensitivity as a result of high contrast resolution for soft tissues. This article aims to describe the normal imaging anatomy and biomechanics of the elbow, the most commonly used MRI protocols and techniques, and common MRI findings related to tendinopathy, ligamentous and osteochondral injuries, and instability of the elbow.

Olecranon Stress Fracture

Olecranon stress fractures are a rare upper extremity fracture that primarily affects throwing athletes. The incidence of olecranon stress fractures are increasing owing to the number of patients playing and the volume of engagement in competitive sports, especially in the pediatric population. However, olecranon stress fractures can present a challenge from a management and a rehabilitation perspective owing to their vague presentation, thereby affecting how these patients are diagnosed and managed. Therefore, it is imperative to further evaluate the disease process, diagnosis, and treatment of this condition to best manage our patients.

Improved diagnostic confidence and accuracy of pediatric elbow fractures with digital tomosynthesis

BACKGROUND

Pediatric elbow fractures are common but remain challenging to accurately diagnose. Digital tomosynthesis is a technique that has shown promise in difficult adult fracture patterns but has not been formally studied in the pediatric population.

OBJECTIVE

To assess the added value of digital tomosynthesis on the detection and diagnostic confidence of pediatric elbow fractures.

MATERIALS AND METHODS

A retrospective study was performed between January 2016 and December 2017 in pediatric patients (≤18 years) to assess the ability of conventional elbow radiographs and digital tomosynthesis to detect elbow fractures. One hundred twenty-one pediatric patients with concern for pediatric elbow trauma (64 males, 57 females; mean age: 8.1 years, range: 1 year to 17 years) were imaged with both conventional elbow radiographs and digital tomosynthesis. Two blinded pediatric radiologists identified fractures and indicated their diagnostic confidence. Observer agreement was assessed with Cohen's Kappa coefficient and a nonparametric Wilcoxon rank sum test was used to compare the degree of diagnostic confidence between standard radiographs alone and standard radiographs with digital tomosynthesis. McNemar's test was used to assess the difference in the rate of fracture detection between the two methods and sensitivity, specificity, precision, accuracy and diagnostic odds ratios were calculated.

RESULTS

Compared with standard radiographs alone, standard radiographs with digital tomosynthesis improved inter-rater agreement, sensitivity, specificity, accuracy, precision and the diagnostic odds ratio for fracture detection and increased diagnostic confidence (Rater 1: P=0.01, Rater 2: P=0.003).

CONCLUSION

The addition of digital tomosynthesis with conventional elbow radiographs improves diagnostic confidence and performance for the detection of pediatric elbow fractures.

Variability of Elbow Radiography in the Injured Child: A Potential Diagnostic Dilemma

BACKGROUND

Radiographic imaging is essential in assessing the severity and treatment of injuries. However, when a radiographic series is of poor quality, its diagnostic utility is limited, especially in cases involving pediatric elbow injuries.

OBJECTIVES

This study aims to investigate the variability of elbow radiographs in the injured child, review parameters used to assess diagnostic quality, and introduce the lateral distal humeral metaphyseal-diaphyseal (LDHMD) ratio as a potential measurement of the quality of a lateral elbow radiograph.

METHODS

A retrospective review was performed of elbow radiographs of children who presented to our hospital. Demographic data, injury, location where the radiograph was obtained, and presence of immobilization were collected. Radiographs were subjectively classified as optimal, adequate, or suboptimal based on several radiographic parameters, one of which was the LDHMD ratio.

RESULTS

There were 286 radiographic series reviewed. Per our assessment of the anteroposterior images, 81% were found to be optimal, 18% adequate, and 1% suboptimal. In contrast, only 24% of the lateral images were deemed optimal, 63% adequate, and 13% suboptimal, therefore making the lateral radiographs the focus of our investigation. The LDHMD ratios of the optimal (n = 21) and suboptimal (n = 11) lateral radiographs without definite fracture were 0.96 and 0.84, respectively (p < 0.001).

CONCLUSIONS

An LDHMD ratio that is approximately 1 and an hourglass sign appearing in the anterior third of the humerus are criteria for determining true pediatric lateral radiograph, and with increased awareness, will lead to improved diagnostic utility of radiographs when assessing the injured child's elbow and determining management.

Intra-articular displacement of an avulsed medial (internal) epicondyle ossification centre in the paediatric elbow: a radiographic finding not to be missed

We present the case of an 11-year-old girl who was presented to the Emergency Department with right elbow pain and swelling following a fall. Radiography demonstrated intra-articular displacement of an avulsed medial epicondyle ossification centre, which was not readily identified at presentation. She proceeded to an uncomplicated open reduction and internal fixation.

Digital tomosynthesis of the pediatric elbow

Imaging pediatric elbow trauma in the acute setting remains diagnostically challenging given difficult patient positioning, multiple ossification centers of the pediatric elbow, overlapping structures, and complex joint anatomy. Digital tomosynthesis is a technique where the X-ray source travels across a limited arc angle, obtaining a series of low-dose exposures that are in turn digitally reconstructed to produce high in-plane resolution at a relatively low overall radiation dose. Digital tomosynthesis is now more commonly integrated into standard radiographic machines and offers a new and exciting way to assess the pediatric elbow. In this review article we discuss the clinical applications of digital tomosynthesis in pediatric elbow trauma along with challenges related to technique, patient positioning and artifacts.

Magnetic resonance imaging of elbow injuries in children

Evaluating elbow injuries is challenging because of the complex anatomy of the joint. In children, injury patterns depend on the sports-specific mechanism as well as the stage of skeletal maturity. This article reviews the anatomy of the elbow and common injury patterns seen in children, with an emphasis on MRI and the throwing athlete. Imaging pitfalls specific to children are described.

Proximal radius fractures in children: evaluation of associated elbow fractures

BACKGROUND

Additional fractures occur in association with proximal radius fractures, but the extent of these secondary injuries has not been systematically assessed.

OBJECTIVE

To ascertain the frequency and nature of additional fractures associated with proximal radius injuries in a large pediatric cohort.

MATERIALS AND METHODS

Radiographs meeting search criteria for proximal radius fracture during a 5-year period were reviewed. Fracture characteristics and the coexistence of additional elbow fractures were recorded and analyzed. The retrospective review was compared with initial interpretation and a blinded review by two pediatric musculoskeletal radiologists.

RESULTS

Four hundred ninety-four proximal radius fractures were included. The radial neck was the most common fracture site (89%). Neck fractures occurred in younger patients (mean: 7.3 years) than head fractures (mean: 13.3 years) (P<0.001). Additional elbow fractures occurred in 39%, most commonly at the olecranon (22%). Additional fractures occurred in younger patients (mean: 7.2 years) than isolated proximal radius fractures (mean: 8.5 years) (P<0.001). Elbow joint effusion and complete or displaced radius fractures were each associated with additional elbow fractures (P<0.001). When compared with initial interpretation, 25% of additional fractures were not identified on initial radiographs, of which 44% were occult retrospectively. Fracture identification demonstrated excellent inter-reader reliability (interclass correlation coefficient [ICC]: 0.88, 0.94), but joint effusion interobserver agreement was only fair (ICC: 0.52, 0.41).

CONCLUSION

Proximal radius fractures in children often occur in association with other elbow fractures, most commonly involving the olecranon. Enhanced awareness of these fracture patterns, especially in the setting of joint effusion or complete and displaced radius fractures, may improve detection to guide appropriate management.

Binomial Classification of Pediatric Elbow Fractures Using a Deep Learning Multiview Approach Emulating Radiologist Decision Making

PURPOSE

To determine the feasibility of using deep learning with a multiview approach, similar to how a human radiologist reviews multiple images, for binomial classification of acute pediatric elbow radiographic abnormalities.

MATERIALS AND METHODS

A total of 21 456 radiographic studies containing 58 817 images of the elbow and associated radiology reports over the course of a 4-year period from January 2014 through December 2017 at a dedicated children's hospital were retrospectively retrieved. Mean age was 7.2 years, and 43% were female patients. The studies were binomially classified, based on the reports, as either positive or negative for acute or subacute traumatic abnormality. The studies were randomly divided into a training set containing 20 350 studies and a validation set containing the remaining 1106 studies. A multiview approach was used for the model by combining both a convolutional neural network and recurrent neural network to interpret an entire series of three radiographs together. Sensitivity, specificity, positive predictive value, negative predictive value, area under the receiver operating characteristic curve (AUC), and their 95% confidence intervals were calculated.

RESULTS

AUC was 0.95, and accuracy was 88% for the model on the studied dataset. Sensitivity for the model was 91% (536 of 590), while the specificity for the model was 84% (434 of 516). Of 241 supracondylar fractures, one was missed. Of 88 lateral condylar fractures, one was missed. Of 77 elbow effusions without fracture, 15 were missed. Of 184 other abnormalities, 37 were missed.

CONCLUSION

Deep learning can effectively classify acute and nonacute pediatric elbow abnormalities on radiographs in the setting of trauma. A recurrent neural network was used to classify an entire radiographic series, arrive at a decision based on all views, and identify fractures in pediatric patients with variable skeletal immaturity.Supplemental material is available for this article.© RSNA, 2019.

Detection of Traumatic Pediatric Elbow Joint Effusion Using a Deep Convolutional Neural Network

OBJECTIVE

The purpose of this study is to determine whether a deep convolutional neural network (DCNN) trained on a dataset of limited size can accurately diagnose traumatic pediatric elbow effusion on lateral radiographs.

MATERIALS AND METHODS

A total of 901 lateral elbow radiographs from 882 pediatric patients who presented to the emergency department with upper extremity trauma were divided into a training set (657 images), a validation set (115 images), and an independent test set (129 images). The training set was used to train DCNNs of varying depth, architecture, and parameter initialization, some trained from randomly initialized parameter weights and others trained using parameter weights derived from pretraining on an ImageNet dataset. Hyperparameters were optimized using the validation set, and the DCNN with the highest ROC AUC on the validation set was selected for further performance testing on the test set.

RESULTS

The final trained DCNN model had an ROC AUC of 0.985 (95% CI, 0.966-1.000) on the validation set and 0.943 (95% CI, 0.884-1.000) on the test set. On the test set, sensitivity was 0.909 (95% CI, 0.788-1.000), specificity was 0.906 (95% CI, 0.844-0.958), and accuracy was 0.907 (95% CI, 0.843-0.951).

CONCLUSION

Accurate diagnosis of traumatic pediatric elbow joint effusion can be achieved using a DCNN.

Pediatric and Adolescent T-type Distal Humerus Fractures

Although fractures of the elbow are extremely common in pediatric patients, the T-type distal humerus fracture is rare and offers unique challenges. The mechanism of injury may be similar to the adult counterpart and is usually caused by a fall onto a flexed elbow or from a direct blow. Diagnosing these injuries may be difficult. They often resemble extension-type supracondylar fractures, yet the treatment algorithm is quite different. In younger patients, percutaneous pinning remains a viable option, but for older adolescents, open reduction and internal fixation provides stable fixation at the elbow and the most reliable restoration of the articular surface. Appropriate imaging, careful radiographic diagnosis, and choice of surgical technique are of paramount importance when treating young patients with this injury. Most pediatric and adolescent patients with T-type distal humerus fractures have results better than those of adults but often worse than other elbow fractures in this age group.

Elbow instability following lateral collateral ligament complex avulsion fracture and joint interposition: an uncommon presentation

The lateral collateral ligament (LCL) complex of the elbow is a capsuloligamentous structure, critical for elbow stability. Though isolated ligamentous injuries have been reported in literature, there are no studies reporting avulsion fractures of the lateral ligamentous complex of the elbow with joint incarceration in a child. An 11-year-old boy presented to the emergency department after a fall from height, with pain and swelling to the lateral side of his left elbow. Radiographs established a fracture of the lateral condyle and CT imaging confirmed an avulsion of the lateral ligamentous complex, with fragments in the inferior radiocapitellar joint. Examination under anaesthesia revealed an unstable elbow with restricted extension, and the child underwent joint debridement and open reduction internal fixation of LCL complex with cannulated screws. At the final follow-up at 15 months, the child regained preinjury level of function.

Pediatric musculoskeletal injuries: role of ultrasound and magnetic resonance imaging

Pediatric musculoskeletal system is particularly prone to traumatic and sports-related injuries, both acute and chronic, i.e., overuse injuries, because of inherent conditions of weakness, such as the open physis, representing the weakest aspect within the bone, the ligamentous supports and changing biomechanics. Being aware that a quick diagnosis is essential to preserve the good functionality of the limb involved, it is mandatory for the radiologist to recognize the most common patterns of these injuries, identifying those requiring a prompt surgery, as well as be confident with the technique performed, and be supported by an important background experience and knowledge skills.

Overuse injuries in children

There has been a substantial increase in the number of children participating in organized competitive sports, which has led to a surge in the number of both acute and overuse injuries. To prevent further complications such as limb deformity and disability, radiologists must be familiar with typical overuse injury patterns in children. Traction apophysitis, chronic physeal injury, and stress fractures are the principal overuse injuries. This article reviews overuse injuries in children with an emphasis on the role of magnetic resonance imaging in diagnosis, prognosis, and treatment.

Elbow your way into reporting paediatric elbow fractures – A simple approach

The evaluation of X-rays of the paediatric elbow in the setting of trauma is challenging. The difficulty arises from the complex developmental anatomy of the elbow, with its multiple ossification centres and the differences in the pattern of injuries between adults and children. It is essential to evaluate the radiographs systematically. This review will provide an overview of the developmental anatomy, the range of soft tissue and skeletal findings, and demonstrate tips and pitfalls in radiographic interpretation in paediatric elbow trauma.

Imaging of physeal injury: overuse

Context:

As the intensity of youth participation in athletic activities continues to rise, the number of overuse injuries has also increased. A subset of overuse injuries involves the physis, which is extremely susceptible to injury. This paper aims to review the utility of the various imaging modalities in the diagnosis and management of physeal injuries in the skeletally immature population.

Evidence Acquisition:

A search for the keywords pediatric, physis, growth plate, x-ray, computed tomography, magnetic resonance imaging, and overuse injury was performed using the PubMed database. No limits were set for the years of publication. Articles were reviewed for relevance with an emphasis on the imaging of growth plate injuries.

Study Design:

Retrospective literature review.

Level of Evidence:

Level 4.

Results:

Three major imaging modalities (radiographs, computed tomography, and magnetic resonance imaging) complement each other in the evaluation of pediatric patients with overuse injuries. However, magnetic resonance imaging is the only modality that offers direct visualization of the physis, and it also offers the best soft tissue contrast for evaluating the other periarticular structures for concomitant injury.

Conclusion:

Imaging has an important role in the diagnosis of physeal injuries, and the information it provides has a tremendous impact on the subsequent management of these patients.

The prognostic value of the fracture level in the treatment of Gartland type III supracondylar humeral fracture in children

A small proportion of children with Gartland type III supracondylar humeral fracture (SCHF) experience troubling limited or delayed recovery after operative treatment. We hypothesised that the fracture level relative to the isthmus of the humerus would affect the outcome. We retrospectively reviewed 230 children who underwent closed reduction and percutaneous pinning (CRPP) for their Gartland type III SCHFs between March 2003 and December 2012. There were 144 boys and 86 girls, with the mean age of six years (1.1 to 15.2). The clinico-radiological characteristics and surgical outcomes (recovery of the elbow range of movement, post-operative angulation, and the final Flynn grade) were recorded. Multivariate analysis was employed to identify prognostic factors that influenced outcome, including fracture level. Multivariate analysis revealed that a fracture below the humeral isthmus was significantly associated with poor prognosis in terms of the range of elbow movement (p < 0.001), angulation (p = 0.001) and Flynn grade (p = 0.003). Age over ten years was also a poor prognostic factor for recovery of the range of elbow movement (p = 0.027). This is the first study demonstrating a subclassification system of Gartland III fractures with prognostic significance. This will guide surgeons in peri-operative planning and counselling as well as directing future research aimed at improving outcomes.

MR imaging of capitellar ossification: a study in children of different ages

BACKGROUND

The capitellar ossification center is used routinely to evaluate elbow alignment on radiography. However, whether capitellar ossification is central and concentric to support this practice is unknown.

OBJECTIVE

To define the pattern of capitellar ossification at different ages of childhood.

MATERIALS AND METHODS

This HIPAA-compliant study was IRB approved. MR imaging examinations from 81 children (ages 1-13 years, at least 3 boys and 3 girls in each age group) were included. We determined the center points of the ossified capitellum and the cartilaginous capitellum on the sagittal and coronal sequences that best showed differentiation between cartilage and bone. Percentage offset of the center of the ossified capitellum from the center of the cartilaginous capitellum was calculated in anterior-posterior, proximal-distal and medial-lateral dimensions, and compared across age groups and between genders. Linear regressions were used to ascertain the effect of age on percentage offset for all patients and for each gender.

RESULTS

Capitellar ossification begins eccentrically with sagittal anterior proximal offset and coronal medial offset. With age, ossification proceeds posteriorly, distally and laterally. Percentage offset gradually diminishes with age. The ossified capitellum centralizes in the sagittal plane by 12-13 years. In the coronal plane, the capitellum ossifies medially beyond the proximal radioulnar joint and remains eccentric at 12-13 years. Centralization in boys lags in the anterior-posterior dimension.

CONCLUSION

Capitellar ossification is an eccentric process, with lag in anterior-posterior centralization in boys. Medial offset persists at 12-13 years. Recognition of this eccentric ossification may allow for more accurate assessment of elbow alignment on radiographs, especially in younger children.

The approach to elbow pain in the pediatric and adolescent throwing athlete

Elbow pain in pediatric throwing athletes can be very concerning and challenging to diagnose. Diagnosis involves determining whether the injury is chronic or acute in nature and the anatomical location of the pain. Physicians should be aware of the sport-specific forces that predispose athletes with immature skeletons to injury and should be familiar with the common presentations of these injuries. In order to narrow the diagnosis, physicians should gather a detailed history of how and when the pain occurred in addition to performing a thorough physical exam that includes tests, such as the modified milking maneuver and the moving valgus stress test. Appropriate imaging helps physicians to confirm the diagnosis and elucidates any associated pathology in patients. In most cases, the treatment given to patients is conservative and involves rest, ice, non-steroidal anti-inflammatory drugs for pain, and an appropriate physical therapy regimen with a progressive return to play when symptoms have resolved. When patients fail to respond to conservative treatment, surgical intervention may be needed. Knowing when to refer patients for orthopedic evaluation helps athletes return to play quickly and safely.