Traumatic elbow effusions in pediatric patients: are occult fractures the rule?

Artificial intelligence-based detection of paediatric appendicular skeletal fractures: performance and limitations for common fracture types and locations

BACKGROUND

Research into artificial intelligence (AI)-based fracture detection in children is scarce and has disregarded the detection of indirect fracture signs and dislocations.

OBJECTIVE

To assess the diagnostic accuracy of an existing AI-tool for the detection of fractures, indirect fracture signs, and dislocations.

MATERIALS AND METHODS

An AI software, BoneView (Gleamer, Paris, France), was assessed for diagnostic accuracy of fracture detection using paediatric radiology consensus diagnoses as reference. Radiographs from a single emergency department were enrolled retrospectively going back from December 2021, limited to 1,000 radiographs per body part. Enrolment criteria were as follows: suspected fractures of the forearm, lower leg, or elbow; age 0-18 years; and radiographs in at least two projections.

RESULTS

Lower leg radiographs showed 607 fractures. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were high (87.5%, 87.5%, 98.3%, 98.3%, respectively). Detection rate was low for toddler's fractures, trampoline fractures, and proximal tibial Salter-Harris-II fractures. Forearm radiographs showed 1,137 fractures. Sensitivity, specificity, PPV, and NPV were high (92.9%, 98.1%, 98.4%, 91.7%, respectively). Radial and ulnar bowing fractures were not reliably detected (one out of 11 radial bowing fractures and zero out of seven ulnar bowing fractures were correctly detected). Detection rate was low for styloid process avulsions, proximal radial buckle, and complete olecranon fractures. Elbow radiographs showed 517 fractures. Sensitivity and NPV were moderate (80.5%, 84.7%, respectively). Specificity and PPV were high (94.9%, 93.3%, respectively). For joint effusion, sensitivity, specificity, PPV, and NPV were moderate (85.1%, 85.7%, 89.5%, 80%, respectively). For elbow dislocations, sensitivity and PPV were low (65.8%, 50%, respectively). Specificity and NPV were high (97.7%, 98.8%, respectively).

CONCLUSIONS

The diagnostic performance of BoneView is promising for forearm and lower leg fractures. However, improvement is mandatory before clinicians can rely solely on AI-based paediatric fracture detection using this software.

2D vs. 3D Ultrasound Diagnosis of Pediatric Supracondylar Fractures

Supracondylar fractures are common injuries in children. Diagnosis typically relies on radiography, which can involve long wait times in the ED, emits ionizing radiation, and can miss non-displaced fractures. Ultrasound (US) has the potential to be a safer, more convenient diagnostic tool, especially with new highly portable handheld 2D point of care US (POCUS). This study aimed to determine the reliability of 2D POCUS for the detection of supracondylar fractures and elbow joint effusions, to contrast the accuracy of 2D POCUS vs. 3DUS vs. radiographs, and to determine whether blinded image interpretation could produce similar results to non-blinded real-time imaging. Fifty-seven children were scanned with 2D POCUS and 3DUS on the affected elbow. US scans were then read by three blinded readers, and the results were compared to gold-standard radiographs. Compared to a gold standard of 30-day radiographic diagnosis, readers of 2D POCUS detected supracondylar fracture and effusion with sensitivities of 0.91 and 0.97, respectively, which were both higher than with 3DUS. Inter-rater reliability of fracture detection was moderate for 2D POCUS (k = 0.40) and 3DUS (k = 0.53). Consensus sensitivities, although high, were lower than reports from some non-blinded studies, indicating that clinical presentation serves as an important factor in detection rates. Our results from consensus US diagnosis support the validity of using 2D POCUS in children for supracondylar fracture and elbow effusion diagnosis.

Nonunion of humeral medial condyle fracture caused by excessive functional exercise: a case report and review of the literature

Background

Medial epicondyle fractures are one of the more common humerus fractures, but humeral medial condyle fracture (HMCF) is rare. Nonunion of medial humeral condyle fractures due to functional exercise is less common.

Case presentation

We report a 5-year-old patient with a nonunion HMCF due to excessive functional exercise, who bruised the elbow 1 year ago and had no positive findings on all imaging studies. On this physical examination, there was a snapping and palpable lump in the elbow joint during movement, but the patient did not feel any discomfort and the range of motion of the joint was normal. X rays and computed tomography (CT) showed that the left HMCF was discontinuous, the broken ends were dislocated, and the joint alignment was poor. Open reduction (OR) and screw fixation was used during the operation, and the patient recovered well at 3-month follow-up.

Conclusions

The rarity and low radiographic appearance of displaced HMCF are easily overlooked and can eventually lead to nonunion HMCF, especially when radiographically difficult to visualize before age 5 years. Therefore, regardless of whether there are signs or imaging abnormalities in the growth process of adolescents, they should be vigilant, shorten the time interval for re-examination, and early detection and timely treatment can avoid some complications caused by this.

Occult Fractures in Children with a Radiographic Fat Pad Sign of the Elbow: A Meta-Analysis of 10 Published Studies

BACKGROUND

A radiographic fat pad sign after an elbow injury in children may indicate an occult fracture. Different incidences and locations of occult fractures have been reported. The primary objective of this meta-analysis was to assess the overall rate of occult fractures in children with a positive fat pad sign from the data of original studies. Secondary objectives were to assess the fracture types and to identify risk factors for sustaining an occult fracture.

METHODS

A systematic literature search of the Embase, MEDLINE, and Cochrane databases was performed according to PRISMA guidelines. Studies on pediatric populations with a positive fat pad sign identified using a lateral elbow radiograph and with follow-up imaging were included in this meta-analysis. Included studies were assessed for risk of bias with use of the MINORS (Methodological Index for NOn-Randomized Studies) instrument.

RESULTS

Ten studies with a total of 250 patients, of whom 104 had an occult fracture, were included. Accounting for heterogeneity between the studies, the overall occult fracture rate was 44.6% (95% confidence interval: 30.4% to 59.7%). The most common fracture locations were the supracondylar humerus (43%), proximal ulna (19%), proximal radius (17%), and lateral humeral condyle (14%). Definitions of a positive pad fad sign were not uniform among studies, and the follow-up imaging modality also varied (radiography, magnetic resonance imaging, or computed tomography). The average MINORS score was 10.1 for the 7 noncomparative studies and 18.7 for the 3 comparative studies, with both averages classified as moderate quality. We were not able to identify risk factors for an occult fracture in the presence of a positive fat pad sign.

CONCLUSIONS

The occult fracture rate was 44.6% in pediatric elbow injuries with a positive fat pad sign. Supracondylar humeral fractures were the most frequently encountered type. The findings of this meta-analysis underline the potential clinical relevance of a positive fat pad sign in children and denote the opportunity for future studies to create evidence-based guidelines.

LEVEL OF EVIDENCE

Level II. See Instructions for Authors for a complete description of levels of evidence.

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.

Standardized sonographic examination of pediatric elbow injuries is an effective screening method and improves diagnostic efficiency

INTRODUCTION

Positive role of ultrasound in the diagnosis of pediatric elbow injuries were confirmed by many papers but no comprehensive, standardized method has been developed for daily clinical practice. The aim of our prospective diagnostic study was to prove the efficacy of a five point sonographic point of care method for detecting different pediatric elbow fractures or dislocations.

METHODS

Between 2016 January and 2017 March 365 children (age 1-14) with suspected closed elbow injury were enrolled in our study. Sonographic point of care examination was carried out by a properly trained resident and two orthopedic surgeons immediately after physical survey. We used a standardized five point sonographic examination. Two plane x-rays were made following sonography according to protocol. Utility of sonographic pictures were analyzed by a radiologist. Cases with images which have not met with standard requirements were excluded. In those cases when primary x-rays were negative and/or any of the ultrasound planes showed positive findings, radiography was repeated after 4 weeks of injury. If we detected callus formation the fracture was considered occult. Cases with images which have not met with standard requirements were excluded. Ultrasonic pictures, evaluation sheets and x-ray results were compared.

RESULTS

Out of the 365 cases we identified 165 with positive findings (45, 2%) by primary x-rays. Distribution of the different injuries were the following: Radial condylar fractures, (n = 29) supracondylar humeral fractures (n = 84 proximal radial fractures, (n = 19) proximal ulnar fractures, (n = 7) fractures with joint dislocations (n = 3) joint dislocations without fractures, n = 2 medial epicondyle fractures (n = 14) fracture combinations (n = 7) We did not find injuries in this series that we could not categorize into these groups. Evaluating the abnormal sonographic dorsal fat pad sign (FPS) as a sole parameter for fracture detection we found sensitivity: 0, 97, specificity: 0,97, positive predictive value: 0,97, negative predictive value: 0,97 Evaluating the effectivity of the four cortical planes we calculated sensitivity 0, 85 specificity 0.96 positive predictive value: 0. 95 negative predictive value 0.87. The overall values of the five planes were the following: specificity0.97 sensitivity 1, positive predictive value 0.97 negative predictive value: 1 Interrater agreements on the cortical plane abnormality were considered good at two examiners and very good at one examiner. (Kappa = 0.79, 0, 81, 0, 79) Agreements on differentiation of elevated, normal fat pad) or lipohaemarthrosis in sonographic pictures were very good in all cases. (Kappa = 0,83, 0,86,0,82) While identification of any displacement or dislocation was possible in 96%, of all cases(n = 59)the exact determination of the type of the injury was possible in only 70,3% (n = 116) CONCLUSIONS: Using the five point ultrasonic examination provides enough information for excluding or confirming the presence of any pediatric elbow fractures or dislocations. The method is quick, simple and can help in the immediate differentiation of the severity of injuries. Sonographic lipohaemarthrosis seems to be more sensitive than elevated fat pad sign for the detection of potential occult fractures. Positive cases should be cleared by x-rays because the exact nature of the fractures are not identifiable only by ultrasound.

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.

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.

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.

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 elbow fractures: a new angle on an old topic

BACKGROUND

The three most common elbow fractures classically reported in pediatric orthopedic literature are supracondylar (50-70%), lateral condylar (17-34%), and medial epicondylar fractures (10%), with fractures of the proximal radius (including but not limited to fractures of the radial neck) being relatively uncommon (5-10%). Our experience at a large children's hospital suggests a different distribution.

OBJECTIVE

Our goals were (1) to ascertain the frequency of different elbow fracture types in a large pediatric population, and (2) to determine which fracture types were occult on initial radiographs but detected on follow-up.

MATERIALS AND METHODS

Review of medical records identified 462 children, median age 6 years and interquartile range for age of 4-8 years (range 0.8-18 years), who were diagnosed with elbow fractures at our institution over a 10-month period. Initial and follow-up radiographs were reviewed in blinded fashion independently by two experienced pediatric musculoskeletal radiologists to identify fracture types on initial and follow-up radiographs.

RESULTS

The most common fractures included supracondylar (n = 258, 56%), radial neck (n = 80, 17%), and lateral condylar (n = 69, 15%). Additional fractures were seen on follow-up exams in 32 children. Of these, 25 had a different fracture type than was identified on initial radiographs. The most common follow-up fractures were olecranon (n = 23, 72%), coronoid process (n = 4, 13%) and supracondylar (n = 3, 9%). Olecranon fractures were significantly more common on follow-up radiographs than they were on initial radiographs (n = 33, 7%; P < .0001). Twenty-six children had more than one fracture type on the initial radiograph. The most common fracture combinations were radial neck with olecranon (n = 9) and supracondylar with lateral condylar (n = 9).

CONCLUSION

Supracondylar fractures are the most frequent elbow fracture seen initially, followed by radial neck, lateral condylar, and olecranon fractures in a distribution different from what has been historically described. The relatively high frequency of olecranon fractures detected on follow-up speaks to their potentially occult nature. Careful attention to these areas is warranted in children with initially normal radiographs.

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.

Performance of the 4-way range of motion test for radiographic injuries after blunt elbow trauma

OBJECTIVES

Acute elbow injuries are common in the acute care setting. A previous study observed that limited active range of motion (ROM) was highly sensitive for radiographic injuries after blunt trauma. Our aim was to validate these findings in patients ≥5 years old with an acute (<24 hours) nonpenetrating elbow injury.

METHODS

This prospective study included a convenience sample of patients undergoing plain radiographs of an injured elbow in 3 emergency departments. Before imaging, treating clinicians completed a standardized data collection sheet including mechanism of injury and 4-way ROM findings (full extension, flexion to 90°, full pronation and supination). Radiographic interpretation by a staff radiologist was used to ascertain the presence of fracture or joint effusion.

RESULTS

The median age of the 251 patients was 24 years. Ninety-two patients (36.7%) had active 4-way ROM, and 159 patients (63.3%) demonstrated limited ROM. Negative radiographs were present in 152 patients (60.6%), whereas 99 patients (39.4%) had abnormal radiographs: 75 with explicit fractures and 24 with only joint effusions. The 4-way ROM elbow test had a sensitivity of 0.99 (95% confidence interval [CI], 0.94-1.00), specificity of 0.60 (95% CI, 0.52-0.68), positive predictive value of 0.62 (95% CI, 0.54-0.69), and negative predictive value of 0.99 (95% CI, 0.94-1.00).

CONCLUSIONS

Active 4-way ROM test is 99% sensitive for all radiographic injures following blunt elbow trauma and 100% sensitive for injuries requiring surgical intervention. Caution should be used in relying on this test in the pediatric population until it is validated in a larger cohort.

Accuracy of the sonographic fat pad sign for primary screening of pediatric elbow fractures: a preliminary study

PURPOSE

The purpose of this study was to evaluate the diagnostic accuracy of the sonographic fat pad sign (FPS) as a predictor for pediatric elbow fractures.

PATIENTS AND METHODS

This is a prospective study of children under 14 years with suspected elbow fractures. All participants underwent at first ultrasonography focused on a FPS followed by standard elbow radiographs. US findings were compared to final fracture diagnosis.

RESULTS

38 out of 79 children had an elbow fracture. A sonographic FPS predicted an elbow fracture with a sensitivity/specificity of 97.3/90.5 %, positive/negative likelihood ratios (LR) were 10.2/0.03 and correct/false classification rates were 93.7/6.3 %. Primary US findings were later reviewed by a blinded physician giving a congruity of 96.2 %. These secondary US findings predicted an elbow fracture with a sensitivity/specificity of 92.1/92.7 %, positive/negative LRs were 12.6/0.09 and correct/false classification rates were 92.4/7.5 %.

CONCLUSION

The sonographic FPS could serve as a useful screening tool in primary evaluation of pediatric elbow injuries. If a fracture is unlikely after clinical and US evaluation, additional radiographs are dispensable, thereby potentially minimizing the radiation burden in childhood and reducing the length of stay in the Emergency Department.

MRI for occult physeal fracture detection in children and adolescents

BACKGROUND

Conventional radiography has limitations in the detection of physeal fractures before the closure of the physis occurs. Fracture detection may be improved by using magnetic resonance imaging (MRI).

PURPOSE

To evaluate the usefulness of MRI for the detection of occult fractures involving the physis when radiography results are negative.

MATERIAL AND METHODS

In this prospective study, 24 children (age range, 3-15 years; mean age, 10.7 years) received MRI if they met the following criteria: acute joint trauma, swelling and tenderness around the joint, limitations in bearing weight, an open physis, and negative radiography results for fractures. Fractures revealed by the MRI were classified according to the Salter-Harris classification system. Joint effusion, bone marrow edema, and periosteal alterations were graded on a three-point scale. The non-parametric Wilcoxon test and Fisher's exact test were used for the statistical evaluation.

RESULTS

From a total of 24 MR data-sets, 23 were evaluated (one patient was excluded due to poor MR image quality). Elbow injuries were present in 10 patients (43.5%), distal tibia injuries in 10 patients (43.5%), and distal femur injuries in three patients (13%). MRI results excluded physeal fractures in 15 (65.2%) of the 23 children. An occult physeal fracture was detected with MRI in eight (34.8%) patients; of these, five (21.7%) had fractures of the elbow, two (8.7%) had fractures of the distal tibia, and one (4.3%) had a fracture of the distal femur. All of the patients with fractures and 11 of the 15 patients without fractures demonstrated bone marrow edema.

CONCLUSION

The frequency of occult fracture, as detected by MRI, was 34.8%. Thus, MRI is a useful additional imaging method for the detection of occult fractures when radiography is negative.

The predictive value of a normal radiographic anterior fat pad sign following elbow trauma in children

OBJECTIVE

The purposes of this study were to describe the characteristics of a normal anterior fat pad (AFP) and to determine the association between a normal AFP and the absence of fracture.

METHODS

A prospective cohort of children aged 1 to 18 years with elbow trauma underwent radiographic examination. All patients received standard orthopedic management and follow-up 7 to 14 days after injury. A pediatric radiologist evaluated all radiographs for the presence or absence of fracture and documented whether the AFP was normal or abnormal on the lateral view. The radiologist also recorded specific measurements of the AFP including the apical angle, which is formed by the intersection of the humerus and the superior aspect of the AFP. The interpretation of the AFP on the initial lateral radiograph was compared with the final patient outcome (fracture/no fracture).

RESULTS

Two hundred thirty-one patients had elbow radiographs; 34 patients (15%) were lost to follow-up. A total of 56 fractures were identified: 49 (87%) on the initial radiograph and an additional 7 (13%) on follow-up radiographs. This latter group was defined as occult fractures. Among the 197 patients available for analysis, 113 (57%) had a normal AFP on the initial radiograph. Of these, 2 children had a final diagnosis of fracture. The sensitivity of a normal AFP was 96.4% (95% confidence interval, 86.6%-99.4%), and the negative predictive value was 98.2% (95% confidence interval, 93.1%-99.7%). There was a significant difference in mean AFP angle when the AFP was read as normal (14.7 [SD, 3.3] degrees) compared with when it was read as abnormal (27.0 [SD, 6.8] degrees) (P < 0.01).

CONCLUSIONS

Our data suggest that a normal AFP is highly associated with absence of elbow fracture and that the determination of a normal AFP can be aided by measuring the apical angle of the AFP.

Capitellum fracture: detecting fat pads may have a significant impact on outcome

Capitellum fractures account for less than 1% of all elbow fractures. Their appearance on plain radiographs may be subtle. It is this combination of features that make these injuries easy to misdiagnose. Misdiagnosis of a nondisplaced capitellum fracture is significant because the capitellum does not have soft tissue attachments and can convert to a displaced fracture that will need surgery. Although a prior study has reported a high incidence of occult elbow fractures when elevated fat pads are present, it did not demonstrate an impact on management. Our case illustrates that because of the capitellum's propensity to displace, detecting fat pads and immobilizing the elbow may have a significant impact on outcome.

Acute elbow trauma in children: role of ultrasonography

BACKGROUND

The diagnosis of occult elbow fracture in children is often challenging due to equivocal or negative repeated radiographic findings.

OBJECTIVE

To evaluate the potential diagnostic role of US in children who have sustained elbow trauma with an elbow joint effusion but no fracture seen on initial radiographs.

MATERIALS AND METHODS

The study included 14 consecutive children (age range 5-15 years) with elbow trauma whose elbow radiographs showed an effusion without fracture who underwent emergency imaging (within the first 72 h) with US and MRI. The aim of US was to demonstrate a lipohaemarthrosis in relation to a cortical fracture. MR imaging was used as the reference to differentiate fracture from bone or muscle contusions.

RESULTS

In seven children US demonstrated a lipohaemarthrosis, and MRI demonstrated a cortical fracture in all these children. Conversely, among the seven children with simple haemarthrosis seen on US, MRI did not identify a cortical fracture in six and demonstrated a cortical fracture in one.

CONCLUSION

Posttrauma elbow joint effusion in children is not always related to a cortical fracture. US appears to be a reliable, accurate, widely available and effective low-cost tool in these cases. The diagnostic clue is the detection of a lipohaemarthrosis in the articular recess.

Can elbow-extension test be used as an alternative to radiographs in primary care?

OBJECTIVE

To evaluate the ability of elbow extension, with the patient in a supine position, as a diagnostic test of an insignificant injury, with the purpose of avoiding unnecessary radiographs.

METHODS

Seventy patients suffering from an acute elbow injury were examined at the accident and emergency department. Inability to fully actively extend the elbow in a supine position was defined as a positive diagnostic test. Radiographs were interpreted by a consultant radiologist, blinded to all clinical examination results. Sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios along with their 95% confidence intervals were calculated for the elbow-extension test.

RESULTS

Forty out of 70 patients had a positive test. Elbow fracture or dislocation was identified radiographically in 22 patients with positive test (sensitivity 92%). Two out of 30 (with negative test) had a hairline radial head fracture, which was found on radiographs (specificity 61%).

CONCLUSION

Elbow extension as a diagnostic test in a primary care setting can predict severe elbow injuries and can be safely used in practices with no radiology facilities.

MDCT of the Elbow in Pediatric Patients with Posttraumatic Elbow Effusions

OBJECTIVE

The purpose of this study was to determine the performance characteristics of MDCT in the detection of fractures in children with posttraumatic elbow effusions and to assess the effect of MDCT findings on clinical management.

SUBJECTS AND METHODS

Unenhanced MDCT of the elbow was prospectively performed without sedation on 31 children 20 months to 16 years old who had posttraumatic elbow effusions. Two blinded reviewers independently and in consensus characterized all MDCT scans as positive or negative for the presence of fracture. Level of interobserver agreement was determined with the kappa statistic. Sensitivity, specificity, positive predictive value, and negative predictive value of MDCT for fracture detection were determined for the consensus MDCT interpretations with follow-up radiographs as the reference standard. Patients were treated with casts and instructed to return in 2-3 weeks for clinical and radiographic follow-up unless a change in management was indicated on the basis of MDCT findings. The frequency of alteration of management was determined.

RESULTS

Both reviewers detected fractures in 15 (48%) of the patients individually and in 16 (52%) of the patients by consensus. Interobserver agreement for fracture detection with MDCT was excellent (kappa = 0.85). The sensitivity, specificity, positive predictive value, and negative predictive value of MDCT in the detection of fractures were 92%, 79%, 79%, and 92%, respectively. Four (13%) of the children had changes in management based on the MDCT findings.

CONCLUSION

MDCT is a sensitive means of evaluating for radiographically occult fractures in children with posttraumatic elbow effusions. It has a high negative predictive value and a high level of interobserver agreement. MDCT findings may lead to alteration of treatment of children with nondisplaced lateral condylar and radial head fractures.

Magnetic resonance imaging in pediatric elbow fractures

PURPOSE

Magnetic resonance imaging (MRI) evaluation of pediatric elbow trauma with or without a visible fracture on radiography.

MATERIAL AND METHODS

MRI was performed in the acute phase in 25 children with an elbow injury. Nine patients with an elbow effusion only on radiographs and 16 with a fracture or luxation seen on radiographs underwent subsequent MRI. No sedation was used.

RESULTS

MRI revealed eight occult fractures (89%) in seven out of nine patients who had only an effusion on radiographs. Based on MRI findings, septic arthritis was suspected in one patient. Two patients out of five with a supracondylar fracture on the radiograph had a cartilage lesion in the humerus. MRI depicted a 3-mm gap on the articular surface in two patients with a lateral condyle fracture, a more accurate fracture location in two patients than the radiographs, and an additional occult fracture in two patients. MRI showed a fracture not seen on radiographs in two of three patients with prior luxation.

CONCLUSION

MRI is a sensitive and accurate method in the diagnosis of pediatric elbow injuries, especially when only an effusion is present on radiographs. Occult fractures are more common in pediatric patients with elbow injury than reported earlier.

The Fat Pad Sign Following Elbow Trauma in Adults

OBJECTIVE

An elbow joint effusion with no fracture seen on radiographs after acute trauma has become synonymous with occult fracture. This study evaluates the incidence of fracture in such cases as determined by MR imaging and the predictive value of an elbow joint effusion.

METHODS

Twenty consecutive patients whose posttrauma elbow radiographs showed an effusion but no fracture and who were suitable for MR imaging were recruited. The elbow effusion size, represented by anterior and posterior fat pad displacement, was measured from the initial lateral elbow radiograph. Suitable candidates underwent MR imaging using a bone marrow sensitive sequence. The time between injury and MR imaging ranged from 0 to 12 days (mean 4 days).

RESULTS

Seventy-five percent of the 20 patients who underwent MR imaging had radiographically occult fractures identified. Some (86.6%) of these fractures were located in the radial head, 6.7% were in the lateral epicondyle, and 6.7% were in the olecranon. Ninety percent had evidence of bone marrow edema. Fifteen percent had collateral ligament disruption identified on MR imaging, and 5% had a loose body. There was no change in patient management as a result of the additional imaging. The anterior fat pad displacement ranged from 5 to 15 mm (mean 9.25), and the posterior fat pad was elevated from 1 to 6 mm (mean 3.2).

CONCLUSION

Our data using MR imaging suggests that fat pad elevation in the presence of recent trauma is frequently associated with a fracture. The size of the effusion, anterior/posterior fat pad elevation, or a combination of both does not correspond to the likelihood of an underlying fracture. MR imaging reveals a broad spectrum of bone and soft tissue injury beyond that recognizable on plain radiographs as demonstrated by all patients in this study.

Elbow effusions in trauma in adults and children: is there an occult fracture?

OBJECTIVE

The purpose of this study was to evaluate whether a detectable abnormality was present on MR imaging without a visible fracture on conventional radiography in the setting of trauma. A recent retrospective study based on the presence or absence of periosteal reaction on follow-up radiographs concluded that fractures were not always present. The discrepancies in the literature over the usefulness of joint effusions as an indicator of fracture caused us to evaluate whether fractures were present more often than identified by conventional radiography. To do this, we used MR imaging.

MATERIALS AND METHODS

Thirteen consecutive patients (age range, 4-80 years; seven children and six adults), whose post-trauma elbow radiographs showed an effusion but no fracture, underwent screening MR imaging.

RESULTS

All patients showed bone marrow edema. Four of the seven children had fractures on screening MR imaging, and all adults had some identifiable fractures.

CONCLUSION

Preliminary data using screening MR imaging suggests that an occult fracture usually is present in the setting of effusion without radiographically visualized fracture.

Acute elbow trauma in children: spectrum of injury revealed by MR imaging not apparent on radiographs

OBJECTIVE

The objective of this study is to evaluate the frequency and significance of unrecognized bone or soft-tissue injury in pediatric patients with elbow trauma assessed with radiographs alone.

SUBJECTS AND METHODS

Fifty children (32 boys and 18 girls; mean age, 7.3 years; age range, 2-12 years) with acute elbow trauma were examined with radiography and MR imaging. Radiographs were categorized into those showing normal findings, an effusion, an equivocal fracture, or an unequivocal fracture. MR examinations were assessed for an effusion, fracture, transphyseal fracture extension, physeal injury, bone bruising, and ligament or muscle injury. Average clinical follow-up was 1.6 years (range, 6-28 months) after injury.

RESULTS

Radiographs showed normal findings in seven children (14%), an effusion only in 17 children (34%), and an unequivocal or equivocal fracture in 26 children (52%). MR imaging showed an effusion in 48 children (96%); unequivocal fracture in 37 children (74%), including transphyseal fracture in seven children (14%) and other physeal injury in three children (6%); bone bruising in 45 children (90%); ligament injury in six children (14%); and muscle injury in 19 children (38%). A less severe spectrum of injury occurred in children with normal findings on radiographs than in those with an effusion or fracture seen on radiography. Follow-up radiographs did not help in the detection of radiographically occult fractures. MR findings had no appreciable effect on patient treatment and no value in predicting duration of convalescence or clinical outcome at an average of 1.6 years after injury.

CONCLUSION

In children with elbow trauma, MR imaging reveals a broad spectrum of bone and soft-tissue injury beyond that recognizable radiographically. However, the additional information afforded by MR imaging has little bearing on treatment or clinical outcome.