Ultrasonographic evaluation of the anterior recess in the normal hip: a prospective study on 166 asymptomatic children

Structural ultrasound of joints and tendons in healthy children: development of normative data

BACKGROUND

Musculoskeletal ultrasound is a well accessible technique to assess disease activity in children with juvenile idiopathic arthritis. Knowledge of reference values of joint structures is indispensable to differentiate between physiological and pathological finding. The aim of this study was to assess the structural sonographic features of joints and tendons in healthy children from several age groups (0.2-18 year), and develop a set of normative data.

METHODS

Greyscale ultrasound was performed in 500 healthy children (age 0.2-18 years) according to a predefined scanning protocol (Additional file 1) including the shoulder, elbow, wrist, second metacarpophalangeal joint, hip, knee, ankle, and first metatarsophalangeal joint). Demographic data and values of cartilage thickness, tendon diameters, and the degree of capsular distention measured by bone-capsular distance (BCD) were collected. Differences according to the sex were assessed by unpaired t-test. Single and multiple regression analyses were performed between the ultrasound outcomes and covariates such as age, height, weight and body mass index. Growth charts and tables were developed with respect to age. Nonparametric quantile regression was applied using the R-packages quantreg and quantregGrowth.

RESULTS

A total of 195 male and 305 female volunteers were included between the age of 0 and 18 years (mean age 8.9; range: 0.2-17.9 years). Cartilage diminished markedly as children aged, and cartilage of the boys was significantly thicker compared to the girls in all joints (p < 0.001). In addition, cartilage became thinner as children's height and weight increased (beta regression coefficients between - 0.27 and - 0.01, p < 0.0001). Capsular distention (i.e., BCD > 0 mm) was uncommon in the ankle, wrist and MCP2 (resp. in 3, 6, and 3% of cases). It was more common in the suprapatellar and parapatellar knee, MTP1 and posterior recess of the elbow (resp. in 34, 32, 46, and 39% of cases). In the hip, some capsular distention was always present. Age was found to be the best predictor for BCD (beta regression coefficients between 0.05 and 0.13, p < 0.0001). Height was, in addition to age, a good predictor of tendon diameter (beta regression coefficients between 0.03 and 0.14, p < 0.0001). Growth curves and tables for each variable were developed.

CONCLUSIONS

Reference values of sonographic cartilage thickness, BCD and diameters of tendons at several joints were established from 500 healthy children, aged between 0.2 and 18 years. Growth charts and tables were developed to distinguish normal findings from pathology in children with complaints suspicious of arthritis.

Ultraschalldiagnostik in der Kinderrheumatologie

Der Artikel gibt einen Überblick zum aktuellen Stand der Ultraschallbefundung in der Kinderrheumatologie und geht insbesondere auf den praktischen Einsatz und die technischen Aspekte der Gelenksonografie ein. Dabei werden auch die wissenschaftlichen Entwicklungen der letzten Jahre zusammengefasst und berücksichtigt. Neben der Gelenksonografie wird die Ultraschalltechnik in der Kinderrheumatologie zunehmend auch auf weitere Körperregionen und -organe ausgeweitet, die für die kinderrheumatologische Diagnostik relevant sind.

The Efficacy of a Brief Educational Training Session in Point-of-Care Pediatric Hip Ultrasound

BACKGROUND

Pediatric limp is a common presenting complaint to emergency departments. Despite this, diagnosis can be difficult in young patients with no history of trauma. Ultrasound can be used to identify a hip effusion, which may be the etiology of limp in pediatric patients. Brief educational training sessions have successfully been used to introduce novice ultrasound users to point-of-care (POC) ultrasound; however, the education of POC hip ultrasound is underexplored, and the efficacy of educational training sessions in this domain remains unknown.

OBJECTIVE

To evaluate the feasibility and efficacy of using a brief educational training session to teach novice ultrasound users to identify hip anatomy and effusions.

METHODS

Medical and physician assistant students were enrolled during an ultrasound education conference. A pretest evaluated prior knowledge, experience, and confidence level regarding POC hip ultrasound. Students attended a brief didactic session and then completed an objective structured assessment of technical skill as well as a posttest.

RESULTS

Twenty-eight students naive to hip ultrasound participated in this study. Levels of training included medical and physician assistant students. Mean test scores increased from the pretest (4.8 of 9, SD = 1.6) to the posttest (7.9 of 9, SD = 0.72) (P < 0.001). Average objective structured assessment of technical skill was 4.6 of 5 (SD, 0.75; 95% confidence interval, 4.3-4.9). After the sessions, confidence levels in identifying landmarks, joint space, and a joint effusion significantly increased (P < 0.001).

CONCLUSIONS

Pediatric hip ultrasound knowledge, performance, skills, and confidence improved as demonstrated by novice ultrasound users after a brief educational training session. Our study shows that a brief, targeted educational intervention was a feasible and effective method of introducing pediatric POC hip ultrasound to novices.

The new role of musculoskeletal ultrasound in the treat-to-target management of juvenile idiopathic arthritis

This article reviews the role of musculoskeletal ultrasound (MSUS) for the diagnosis, monitoring and treat-to-target management of JIA. Technological advancements in MSUS allow more precise evaluation of arthritis, tenosynovitis and enthesitis versus clinical examination alone, which may assist treatment decisions. In adult studies, serum and synovial biomarkers have correlated with MSUS findings. Within paediatric rheumatology, significant developments in the definition of normal and pathology, a necessity for the future integration of MSUS into treat-to-target management, have already been reached or are underway, which in turn could allow tighter control of disease activity and earlier identification of treatment response and failure, bringing the goal of 'precision medicine' closer. Additionally, the utility of MSUS for the evaluation of subclinical disease remains an unexamined area of interest. 'Ultrasound remission' combined with clinical assessment and immunological markers could therefore potentially improve the treat-to-target management of JIA.

Imaging assessment of children presenting with suspected or known juvenile idiopathic arthritis: ESSR-ESPR points to consider

Juvenile idiopathic arthritis (JIA) is the most common paediatric rheumatic disease. It represents a group of heterogenous inflammatory disorders with unknown origin and is a diagnosis of exclusion in which imaging plays an important role. JIA is defined as arthritis of one or more joints that begins before the age of 16 years, persists for more than 6 weeks and is of unknown aetiology and pathophysiology. The clinical goal is early suppression of inflammation to prevent irreversible joint damage which has shifted the emphasis from detecting established joint damage to proactively detecting inflammatory change. This drives the need for imaging techniques that are more sensitive than conventional radiography in the evaluation of inflammatory processes as well as early osteochondral change. Physical examination has limited reliability, even if performed by an experienced clinician, emphasising the importance of imaging to aid in clinical decision-making. On behalf of the European Society of Musculoskeletal Radiology (ESSR) arthritis subcommittee and the European Society of Paediatric Radiology (ESPR) musculoskeletal imaging taskforce, based on literature review and/or expert opinion, we discuss paediatric-specific imaging characteristics of the most commonly involved, in literature best documented and clinically important joints in JIA, namely the temporomandibular joints (TMJs), spine, sacroiliac (SI) joints, wrists, hips and knees, followed by a clinically applicable point to consider for each joint. We will also touch upon controversies in the current literature that remain to be resolved with ongoing research. KEY POINTS: • Juvenile idiopathic arthritis (JIA) is the most common chronic paediatric rheumatic disease and, in JIA imaging, is increasingly important to aid in clinical decision-making. • Conventional radiographs have a lower sensitivity and specificity for detection of disease activity and early destructive change, as compared to MRI or ultrasound. Nonetheless, radiography remains important, particularly in narrowing the differential diagnosis and evaluating growth disturbances. • Mainly in peripheral joints, ultrasound can be helpful for assessment of inflammation and guiding joint injections. In JIA, MRI is the most validated technique. MRI should be considered as the modality of choice to assess the axial skeleton or where the clinical presentation overlaps with JIA.

Ultrasound imaging in paediatric rheumatology

The role of ultrasound imaging in the diagnosis and monitoring of paediatric rheumatic diseases with special emphasis on recent scientific work regarding the evidence base and standardization of this technique is being reviewed. An overview of the most important practical aspects for the use of musculoskeletal ultrasound in a clinical setting is also provided. Huge scientific efforts and advances in recent years illustrate the increasing importance of musculoskeletal ultrasound in pediatric rheumatology. Several studies focused on setting an evidence-based standard for the ultrasound appearance of healthy and normal joints in children of all age groups. Physiologic vascularization and ossification were two main aspects of these studies. Other publications demonstrate that ultrasound imaging is also an important and useful tool to detect pathology as synovitis, tenosynovitis or enthesitis in children and to monitor pediatric patients with rheumatic conditions. Important practical aspects include training in the use of correct ultrasound techniques, as well as knowledge and experience of normal pediatric sonoanatomy and the appearance of pathological findings on ultrasound.

Emergence of Musculoskeletal Ultrasound Use in Pediatric Rheumatology

PURPOSE OF REVIEW

To summarize recent international efforts on standardization and validation of pediatric musculoskeletal ultrasound and determine its role in diagnosis and monitoring of disease in pediatric rheumatology.

RECENT FINDINGS

Over the past decade, significant progress has been made on building the evidence base for musculoskeletal ultrasound in pediatric rheumatology. This includes the clear definition of the sonographic appearance of the normal pediatric joint and enthesis on ultrasonography, definitions for pathology, and the establishment of a specific scoring system for the pediatric knee. Ultrasonography has been shown to have an important role in the detection of subclinical synovitis and can predict flares in children considered to be in remission clinically. Musculoskeletal ultrasound is likely going to play an important role in complementing the clinical exam especially in juvenile idiopathic arthritis. Given the powerful therapeutic tools available, it will support early diagnosis and precisely determine remission status. In a treat to target approach, it will greatly help to define the targets that need to be reached.

The role of imaging in juvenile idiopathic arthritis

INTRODUCTION

The prognosis of juvenile idiopathic arthritis (JIA) has changed dramatically due to the availability of novel drugs. Prompt diagnosis and treatment are essential to prevent permanent joint damage. As a result, methods to improve JIA diagnosis and prognosis are of high priority to tailor treatment strategies and maximize their efficacy. Musculoskeletal ultrasound and magnetic resonance imaging are more sensitive than clinical examination and radiography in the detection of joint involvement and might play a substantial role to optimize the management of JIA. Areas covered: This review compiles an inventory of potential uses of imaging studies in the modern practice of pediatric rheumatology, together with a critical analysis of the major challenges that are still to be addressed. Imaging appearance of normal growth-related changes of the musculoskeletal system will be discussed. Expert commentary: Knowledge of the evolving patterns of skeletal maturity is paramount to define pathological findings and avoid misinterpretations. Establishing a novel radiological algorithm for a rational use of imaging in JIA is of high priority to allow a speedier integration of imaging into the clinical workflow and decision-making process.

Normative ultrasound references for the paediatric wrist; dorsal soft tissues

Objective

To report novel ultrasound (US) references for the healthy paediatric wrist.

Methods

Healthy children and adolescents had an US examination including Doppler, of the right wrist, using a mid-sagittal image through the radiocarpal (RC)/midcarpal (MC) joints. These features were noted: appearances and depth of the recess, with an additional measurement in the flexed position and number of Doppler signals within the recess in close proximity to the joint. In a second, blinded session, all images were reassessed by the same observer.

Results

In total, 116 subjects (59 girls) aged 6–16 years (mean 10 years and 11 months) were included. The RC recess was visible in 71, of which 60 were non-bulging and 11 were bulging. In flexion, the thickness decreased in 60 (84.5%), suggestive of joint fluid. Of the 54 visible MC recesses, 45 (83.3%) thinned in flexion. The mean depths of the RC and MC recesses were 0.4 mm (SD 0.5, range 0–2.9) and 0.5 mm (SD 0.6, range 0–2.4), respectively, with no differences according to sex, but with increasing depths by age.

For the RC joints, at least one Doppler signal was seen in the recess in 9/116 joints (7.8%), whereas this was true for 3.5% of the MC recesses. There were no statistically significant association between the depth of the RC or MC recesses and number of hand active sport activities (P=0.733 and P=0.091, respectively).

Conclusion

The appearances of the dorsal RC and MC recesses in healthy children may mimic pathology. Hence, findings should be interpreted carefully.

Age-dependent arthrosonographic reference values of the hip joint in healthy children and adolescents - a cross-sectional multicenter ultrasound study

BACKGROUND

Musculoskeletal US is a noninvasive imaging method for diagnosing and monitoring inflammatory rheumatic diseases.

OBJECTIVES

To develop age- and gender-related arthrosonographic reference intervals for the hip joint of healthy children and adolescents.

MATERIALS AND METHODS

In a cross-sectional US study, we examined both hip joints of 445 children and adolescents with an age range of 1 year to 18 years. We measured the distance between the bone surface and the outer margin of the joint capsule to define the bone-capsule distance, the joint capsule and cartilage thickness, and the capsule layer thickness. Reference values were calculated. The shape of the joint capsule and bone-capsule junction zone were analyzed qualitatively. An intraobserver analysis was performed.

RESULTS

Bone-capsule distance, capsule thickness and the anterior capsule layer increase with age. In contrast, joint cartilage decreases. The posterior capsule layer exhibited constant thickness across all age groups. The difference between both body sides and gender was collectively less than 0.5 mm. The intraobserver variations were within the calculated reference intervals. The insertion of the capsule to the bone was mostly a peaked one. The capsule shape had a convex or straight configuration in a neutral position and a concave position during outward rotation. The intraobserver analysis revealed good to very good concordance.

CONCLUSION

We propose age- and gender-related reference intervals for the bone-capsule distance, joint capsule and cartilage thickness of the hip.

Establishing percentile charts for hip joint capsule and synovial cavity thickness in apparently healthy children

BACKGROUND

The usefulness of musculoskeletal ultrasonography (MSUS) in paediatric population is limited by lack of reference values. One of such parameters is hip joint capsule thickness, postulated as an early measure for synovitis. However, the joint capsule is hardly a distinguished structure from slit synovial cavity in patients with little or no fluid collection. Therefore, in patients without effusion, it is more convenient to measure hip joint capsule thickness together with synovial cavity. The aim of the study was to establish percentile chart for hip joint capsule and synovial cavity thickness (HJC&SCT) in apparently healthy children.

MATERIAL AND METHODS

The analysis included 816 US of hip joint in 408 children without musculoskeletal disorders, distributed equally throughout the whole developmental period in 18 one-year subgroups. Hip joints US was performed according to standard protocol including measurement of HJC&SCT in a single rheumatology centre by three investigators.

RESULTS

The 3rd, 10th, 25th, 50th, 75th, 90th, and 97th HJC&SCT percentile curves were depicted in the age and height charts for the combined group of girls and boys. The median HJC&SCT values were increasing with age from 3.7 (C10 - C90: 3.3 - 4.2) mm in the first year of life up to 6.7 (5.8 - 7.3) in 16 years old, and above. In a similar way the increase was seen with height from 3.9 (3.5 - 4.7) mm in shorter than 95 cm to 6.9 (6.2 - 7.4) mm in taller than 169 cm subjects. Intra-observer and inter-observer mean precision was less than 1.8 and 12.5%, respectively.

CONCLUSION

The developed centile chart for hip joint capsule and synovial cavity thickness in the paediatric population is expected to improve detection of hip joint capsule disorders, including synovitis in juvenile idiopathic arthritis.

Emergency Department Point-of-Care Hip Ultrasound and Its Role in the Diagnosis of Septic Hip Arthritis: A Case Report

We present a case of an 11-year-old girl with eye swelling and hip pain and the use of point-of-care hip ultrasound (US) to facilitate diagnosis of a septic hip. We review the US technique, sonographic findings, and relevant literature regarding point-of-care hip US.

Imaging of Hip Pain: From Radiography to Cross-Sectional Imaging Techniques

Hip pain can have multiple causes, including intra-articular, juxta-articular, and referred pain, mainly from spine or sacroiliac joints. In this review, we discuss the causes of intra-articular hip pain from childhood to adulthood and the role of the appropriate imaging techniques according to clinical suspicion and age of the patient. Stress is put on the findings of radiographs, currently considered the first imaging technique, not only in older people with degenerative disease but also in young people without osteoarthritis. In this case plain radiography allows categorization of the hip as normal or dysplastic or with impingement signs, pincer, cam, or a combination of both.

The role of ultrasound in the emergency department evaluation of the acutely painful pediatric hip

Children presenting with hip pain or a limp are a diagnostic challenge for the clinician. The differential diagnosis is extensive, and the workup can be broad. This review focuses on differentiating between transient synovitis and septic arthritis of the hip. The role of bedside ultrasound in the clinical evaluation of these patients is addressed, including the technique and appropriate indications for bedside ultrasound of the hip in the emergency department.

Musculoskeletal ultrasonography of the lower extremities in infants and children

Ultrasonography is a powerful diagnostic imaging tool for evaluating lower extremity anatomy and pathology in children. Indications for pediatric musculoskeletal lower extremity sonography include developmental dysplasia of the hip, hip joint sonography for the child with a painful hip, evaluation and characterization of superficial soft-tissue masses, evaluation for deep venous thrombosis, and foreign body localization, characterization and removal. This review highlights these established indications, but primarily focuses on additional US applications for evaluation of the lower extremities, including diagnosis and characterization of arthritis and monitoring of therapy, evaluation of tendon tears and muscle strain injuries, characterization of soft-tissue masses and evaluation of certain congenital abnormalities of the lower extremities. Techniques for optimal utilization of musculoskeletal US in children are also discussed.

Ultrasound-guided hip arthrocentesis in a child with hip pain and Fever

Children presenting to the emergency department with hip pain and fever are at risk for significant morbidity due to septic arthritis. Distinguishing between septic arthritis and other causes of hip pain may be challenging. Sonographic visualization of the hip with real-time ultrasound-guided arthrocentesis may allow faster differentiation between etiologies, hastening definitive therapy and improving analgesia. This report describes the use of hip sonography in a case of Lyme arthritis. The authors review the medical literature in support of bedside hip sonography and discuss how to perform ultrasound-guided hip arthrocentesis. Clinical findings in septic and Lyme arthritis are also described.

Hip ultrasound

In newborns, US has an established role in the detection and management of developmental dysplasia of the hip. Later in childhood, when the limping child is a major diagnostic dilemma, US is extremely helpful in the identification of the varied disease processes underlying this condition, as transient synovitis, septic arthritis, Perthes disease and slipped femoral capital epiphysis. In adolescent practicing sporting activities, US is an excellent means to identify apophyseal injures about the pelvic ring, especially when avulsions are undisplaced and difficult-to-see radiographically. Later on, in the adulthood, US is an effective modality to diagnose tendon and muscle injuries about the hip and pelvis, identify effusion or synovitis within the hip joint or its adjacent bursae and guide the treatment of these findings. The aim of this article is to provide a comprehensive review of the most common pathologic conditions about the hip, in which the contribution of US is relevant for the diagnostic work-up.

Doppler sonography of the anterior ascending cervical arteries of the hip: evaluation of healthy and painful hips in children

OBJECTIVE

We evaluated the Doppler sonography of small feeding arteries to the femoral head in children.

SUBJECTS AND METHODS

In a prospective study of 224 hips in 112 patients (mean age, 5 years 11 months), the anterior ascending cervical arteries of the hip were identified with color Doppler sonography. Subsequently, we measured the resistive index (RI) with pulsed Doppler sonography.

RESULTS

In 61% (137/224) of hips, a Doppler signal could be obtained. In asymptomatic hips (n = 64), the mean RI was 0.58. In symptomatic hips, the definitive diagnoses and mean values of RI included transient synovitis (n = 31) and 0.92, Perthes' disease (n = 9) and 0.67, and miscellaneous (n = 5) and 0.68. In 28 symptomatic hips, no definite diagnosis could be determined and the complaints spontaneously disappeared during follow-up (mean RI, 0.57). We found no statistically significant difference in the RI of symptomatic versus asymptomatic hips, except in patients with transient synovitis (p < 0.001). In 11 hips with transient synovitis that were reexamined after 4-6 weeks, the RI returned to normal (0.57). The RI in symptomatic hips showed a positive correlation with the amount of effusion (r = 0.69, p < 0.001). In symptomatic and asymptomatic hips, we found no correlation with age (p = 0.9 and 0.1, respectively).

CONCLUSION

The deep capsular vessels of the hip joint can be evaluated on Doppler sonography in more than 60% of hips. Also, the RI is age independent and correlates with the amount of effusion.

Ultrasound of the adult hip

The adult hip is a new and challenging site for evaluation with ultrasound (US). Clinically, diseases involving the hip region may be difficult to diagnose without the help of imaging. The hip region is a crossroad for numerous vascular, nervous, and muscular structures that pass between the trunk and the lower extremity. Thus, inflammatory processes and neoplasms may spread to and from the hip, buttock, thigh, pelvis, and retroperitoneum, and trauma may also effect the adjacent areas of the trunk and thigh. Because it is a crossroad, many conditions that are not specific to the hip occur in this area, including inguinal lymphadenopathy, pathology from the abdomen or the genitalia (intestinal hernia, inflammation, and infection), and even referred pain from spinal disorders. The goals of US imaging are the detection and localization of these pathological processes, the differentiation of intra-articular andextra-articular pathology, and the performance of diagnostic and therapeutic interventional procedures. This article reviews the hip anatomy, followed up by a discussion of the US evaluation and differential diagnosis of common pathology occurring in the hip area. This includes joint effusion, arthritis, loose bodies, bursitis, pseudoaneurysm, muscle and tendon diseases, as well as tumor and tumor-like lesions such as hematoma, abscess, and lymphadenopathy.

Pediatric hip sonography. Diagnosis and differential diagnosis

As with any sonographic study, the accuracy of the examination is related to the skill and experience of the examiner. In this review of pediatric hip sonography, we have reviewed pitfalls and differential diagnoses for the infant suspected of DDH and for the older child presenting with a painful hip. The learning process for DDH evaluation is prolonged and more difficult than learning to assess the hip for effusion.

Anterior joint capsule of the normal hip and in children with transient synovitis: US study with anatomic and histologic correlation

PURPOSE

To study the anatomic components of the anterior joint capsule of the normal hip and in children with transient synovitis.

MATERIALS AND METHODS

Six cadaveric specimens were imaged with ultrasonography (US) with special attention to the anterior joint capsule. Subsequently, two specimens were analyzed histologically. These anatomic findings were correlated with the US findings in 58 healthy children and 105 children with unilateral transient synovitis.

RESULTS

The anterior joint capsule comprises an anterior and posterior layer, mainly composed of fibrous tissue, lined by only a minute synovial membrane. Both fibrous layers were identified separately at US in 98 of 116 (84%) hips of healthy subjects and in all hips with transient synovitis. Overall, the anterior layer was thicker than the posterior layer. In transient synovitis compared with normal hips, no significant thickening of both layers was present (P = .24 and .57 for the anterior and posterior layers, respectively). Normal variants include plicae, local thickening of the capsule, and pseudodiverticula.

CONCLUSION

Increased thickness of the anterior joint capsule in transient synovitis is caused entirely by effusion. There is no US evidence for additional capsule swelling or synovial hypertrophy.