Sonography of the painful hip in children: 500 consecutive cases

Transient Hip Synovitis, 146 Cases, Origin and Duration

Transient hip synovitis is one of the most common paediatric orthopaedic diseases. This non-controlled interventional study investigated the origin, clinical findings, imaging and the duration of symptoms. 146 affected patients out of the total of 27659 patients under 18 years result in an incidence of 0.53%. 76.7% boys outweighed 23.3% girls (1.8-12.9 years [Ø 6.3 y, boys Ø 6.5 y, girls Ø 6.2 y]). Diagnoses were defined by ultrasound and the absence of concurrent diseases. In 60.5% of patients, the right hip was affected, in 39.5% the left. A single patient had CF on both sides but not at the same time. No simultaneous incidence was recorded. There were two singular recurrences. Within the study period, we counted 11 cases of Perthes' disease, 2 juvenile hip arthritis and one septic hip. Patients' history showed 41.0% viral infections, 21.6% physical exertion and 15.1% singular trauma. In 22.3% no origin could be named. Clinical aspects included pain in inward rotation (51.5%), in hip flexion (49.3%) and limping (37.5%). Ultrasound depicted medium joint effusion in 53.4%, marked effusion in 46.6% and synovial thickening in 17.1% of patients. 119 patients could be followed up weekly. Joint effusion vanished after 3-36 days (Ø 13.3 d), clinical symptoms Ø 1.6 days earlier. Total duration in terms of sonographic appearance of effusion was 3 to 37 days (Ø 19.1 d).

Pediatric musculoskeletal infections

PURPOSE OF REVIEW

The aim of this article is to review the recent guidelines and literature regarding the diagnosis and the treatment of common pediatric musculoskeletal infections: septic arthritis, osteomyelitis, pyomyositis, and Lyme disease.

RECENT FINDINGS

In the last decade, a better understanding of the causative organisms of common bacterial infections, including Kingella , leads to prompt targeted antimicrobial coverage in all musculoskeletal infections. Prompt diagnosis and treatment continues to be the mainstay in the treatment of children with osteoarticular infections. Efforts to improve early detection have lead to improving rapid lab diagnostic testing; however, more advanced diagnostics such as arthrocentesis for septic arthritis and MRI for osteomyelitis and pyomyositis, remain the gold standard. Shorter and narrowed antibiotic courses, with appropriate transition to outpatient oral treatment provide effective infection clearance and reduction in complications of disease.

SUMMARY

Advances in diagnostics, including pathogen identification as well as imaging continues to improve our ability to diagnose and treat these infections, although still lack ability to provide definitive diagnosis without more invasive nor advanced techniques.

Usefulness of MRI findings in differentiating between septic arthritis and transient synovitis of hip joint in children: A systematic review and meta-analysis

Purpose

Septic arthritis (SA) of the hip joint is a serious infection which can lead to more irreversible complications. Differentiating Septic arthritis from Transient synovitis (which is the most common cause of painful hip in children) is difficult and very important to prevent serious complications which can occur with Septic arthritis. The aim of this study was to find out the MRI findings which can differentiate between these two conditions.

Methods

Systematic literature search was conducted according to the PRISMA guidelines on MEDLINE(PubMed), Google Scholar, ScienceDirect, and world Health Organization Virtual Health Library, up to April 2022. Studies that compared MRI findings between Septic Arthritis and Transient Synovitis of hip joint in children were included. The pooled sensitivity and specificity estimates of these findings were calculated using MetaDTA version 2.0.

Results

Six studies were included in qualitative analysis and five were included in quantitative analysis. Pooled sensitivity and specificity of synovial enhancement were 94.2 % (95 % CI, 45.2–99.7 %) and 60.6 % (95% CI, 6–97.4 %) respectively. Soft tissue changes had pooled sensitivity and specificity of 75 % (95% CI, 57.5–86.9 %) and 69.9 % (95 % CI, 46.5–86.2 %) respectively. Pooled sensitivity and specificity of femoral head changes were 41.5 % (95 % CI, 15.9–72.7 %) and 87.3 % (95 % CI, 75.5–93.8 %) respectively. Bone marrow changes had pooled sensitivity and specificity of 70 % (95 % CI, 26.8–93.7 %) and 99.9 % (95 % CI, 28.7–100 %) respectively.

Conclusion

MRI findings especially bone marrow changes were found to be useful in differentiating septic arthritis from transient synovitis among children presented with painful hip after exclusion of other causes.

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

OBJECTIVES

The objective of this study was to investigate the predictive value of asymmetric joint space widening on simple radiographs for the presence of hip joint effusion in children with unilateral hip pain.

METHODS

Sixty-eight patients aged 6 to 17 years with both simple radiograph and magnetic resonance imaging of both hips were retrospectively reviewed. We evaluated the predictive effects of radiographic surrogates for joint space widening on the presence of high-grade hip joint effusion. We also sought to investigate a predictive model for the presence of hip joint effusion with the patients' clinical and radiological data.

RESULTS

Radiographic values showed high specificity but low sensitivity for the presence of high-grade joint effusion. On multivariate analysis, sex and the difference ratio of medial and superior gaps were independent predictive factors for unilateral high-grade hip joint effusion.

CONCLUSIONS

For children 6 years and older with asymmetric hip joint space widening on simple radiographs, further evaluations for the presence of hip joint effusion should be considered because of its high specificity. The predictability can improve if both medial and superior gaps, and sex are included in the evaluation. In girls, hip joint effusion seems to widen the joint space more easily than in boys, which may be owing to the more ligamentous laxity of and less musculature around the hip in girls. However, the risk of joint effusion should not be underestimated even if a child presents symmetry on the simple radiograph because of its low sensitivity and the possibility of bilateral involvements or early stage of diseases.

Point-of-care hip ultrasound leads to expedited results in emergency department patients with suspected septic arthritis

BACKGROUND

The evaluation of septic hip arthritis often incorporates the utilization of hip ultrasonography to determine the presence of a hip joint effusion, as well as to guide arthrocentesis. Point-of-care (POC) hip ultrasound has previously been demonstrated to be accurate when performed by the emergency physician. Time to diagnosis and subsequent intervention in septic arthritis (SA) is critical to favorable outcomes.

METHODS

Retrospective single-center study of all emergency department (ED) patients who had a POC or radiology hip ultrasound or arthrocentesis as part of their ED evaluation for SA in a 3-year period. We investigated the difference in time to obtain hip ultrasonography results and the time to arthrocentesis between radiology and emergency physician-performed studies in cases of suspected septic hip arthritis.

RESULTS

Seventy-four patients met inclusion criteria. The median time to hip ultrasound completion was 68 (interquartile range [IQR], 38.8-132) minutes in the emergency physician-performed ultrasound group versus 208.5 (IQR, 163.8-301.3) minutes for the radiology group (P < 0.001). A total of 17 patients had a hip arthrocentesis performed. Time to arthrocentesis was 211 (IQR 141.3-321.5) minutes in the emergency physician-performed arthrocentesis group and 602 (IQR 500-692) minutes in the radiology arthrocentesis (P < 0.001).

CONCLUSION

There was a statistically shorter time to ultrasound result and arthrocentesis when POC hip ultrasound was utilized by the emergency physician. Given that unfavorable outcomes in SA are associated with delay in treatment, further study is warranted to determine if emergency physician-performed hip ultrasound and arthrocentesis could lead to improved patient-centered clinical end points.

US Evaluation of Juvenile Idiopathic Arthritis and Osteoarticular Infection

Juvenile idiopathic arthritis (JIA) and osteoarticular infection can cause nonspecific articular and periarticular complaints in children. Although contrast material-enhanced magnetic resonance imaging is the reference standard imaging modality, musculoskeletal ultrasonography (US) is emerging as an important adjunct imaging modality that can provide valuable information relatively quickly without use of radiation or the need for sedation. However, diagnostic accuracy requires a systemic approach, familiarity with various US techniques, and an understanding of maturation-related changes. Specifically, the use of dynamic, Doppler, and/or multifocal US assessments can help confirm sites of disease, monitor therapy response, and guide interventions. In patients with JIA, ongoing synovial inflammation can lead to articular and periarticular changes, including synovitis, tenosynovitis, cartilage damage, bone changes, and enthesopathy. Although these findings can manifest in adult patients with rheumatoid arthritis, important differences and pitfalls exist because of the unique changes associated with an immature and maturing skeleton. In patients who are clinically suspected of having osteoarticular infection, the inability of US to evaluate the bone marrow decreases its sensitivity. Therefore, the US findings should be interpreted with caution because juxtacortical inflammation is suggestive, but neither sensitive nor specific, for underlying osteomyelitis. Similarly, the absence of a joint effusion makes septic arthritis extremely unlikely but not impossible. US findings of JIA and osteoarticular infection often overlap. Although certain clinical scenarios, laboratory findings, and imaging appearances can favor one diagnosis over the other, fluid analysis may still be required for definitive diagnosis and optimal treatment. US is the preferred modality for fluid aspiration and administering intra-articular corticosteroid therapy. ^© RSNA, 2017.

Non-traumatic limping in Paediatric Emergencies: Epidemiology, evaluation and results

INTRODUCTION

Non-traumatic limping is a common reason for consultation in paediatric emergencies. Although transient synovitis of the hip (TS) is the most frequent diagnosis, there are cases of limping secondary to serious pathologies. The aim of this review is to describe the variables related to non-traumatic limp that come to the paediatric emergency department to establish the best management protocol, making the most of resources and speeding up emergency care.

MATERIAL AND METHOD

A prospective study was conducted, selecting all children less than 15 years old who consulted aspaediatric emergencies for non-traumatic limping during the 2014. Clinical variables, complementary examinations and diagnoses were collected in the emergency room consultation and 6 months after the consultation RESULTS: During 2014, 146 patients (0.69% of the emergencies) were included in the non-traumatic limping study. Four cases of severe limping were diagnosed: 2 leukaemias, 1 septic arthritis and 1 acetabular bone tumour. The most frequent diagnosis was TS (53.16%). At 6 months, 135 children (92.4%) had resolved lameness. The diagnosis was changed in 9 children (6.1%). Children with TS had fewer days of evolution, and 77% were between 3 and 10 years old. Children with a final diagnosis of severe pathology had a limp for longer, fever and did not weight bear on ambulation.

CONCLUSIONS

In limping of probable hip origin, at the ages of between 3 and 10, without fever or systemic symptoms and of less than one week's onset, it is possible to make a clinical diagnosis of TS limiting the use of complementary examinations.

Pediatric emergency medicine point-of-care ultrasound: summary of the evidence

The utility of point-of-care ultrasound is well supported by the medical literature. Consequently, pediatric emergency medicine providers have embraced this technology in everyday practice. Recently, the American Academy of Pediatrics published a policy statement endorsing the use of point-of-care ultrasound by pediatric emergency medicine providers.  To date, there is no standard guideline for the practice of point-of-care ultrasound for this specialty. This document serves as an initial step in the detailed "how to" and description of individual point-of-care ultrasound examinations.  Pediatric emergency medicine providers should refer to this paper as reference for published research, objectives for learners, and standardized reporting guidelines.

The child with joint pain in primary care

Joint pains are a common reason for children to present to primary care. The differential diagnosis is large including some diseases that do not primarily affect the musculoskeletal system. Although the cause for many patients will be benign and self-resolving, in rare cases the diagnosis is associated with long-term morbidity and mortality if not detected early and appropriately treated. These include primary and secondary malignancies, septic arthritis, osteomyelitis, inflammatory arthritis, slipped upper femoral epiphysis (SUFE) and non-accidental injury. We highlight the importance of a thorough history and directed yet comprehensive examination. A diagnostic algorithm is provided to direct primary care physicians' clinical assessment and investigation with the evidence base where available. In many cases, tests are not required, but if there is suspicion of malignancy, infection or inflammatory conditions, laboratory tests including full blood count, blood film, erythrocyte sedimentation rate, C-reactive protein and lactate dehydrogenase help to support or exclude the diagnosis. Autoimmune tests, such as antinuclear antibodies and rheumatoid factor, have no diagnostic role in juvenile idiopathic arthritis; therefore, we advise against any form of 'rheumatological/autoimmune disease screen' in primary care. Imaging does have a place in the diagnosis of joint pains in children, with plain radiographs being most appropriate for suspected fractures and SUFE, whilst ultrasound is better for the detection of inflammatory or infective effusions. The appropriate referral of children to paediatric rheumatologists, oncologists, orthopaedic surgeons and the emergency department are discussed.

Case 2: a 10-year-old girl with hip pain

In this continuing series designed for pediatric radiology trainees, the imaging management of hip pain and a discovered bony mass are dissected through a specific case of a preadolescent.

The use of ultrasound in the management of septic arthritis of the hip

In the assessment of septic arthritis of the hip in a pediatric population, ultrasound is a safe and easily conducted method to confirm an effusion. The need for MRI to further evaluate the patient for adjacent infection before treatment is debatable. Once an effusion is confirmed on ultrasonography, we have found that septic arthritis of the hip does not need advanced imaging before arthrotomy and debridement. Patients who fail to clinically respond to an initial hip arthrotomy and appropriate antibiotics may benefit from an MRI for the identification of concomitant infections that may require surgical intervention.

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.

Sonographic evaluation of hip joint effusion in osteoarthritis with correlation to radiographic findings

PURPOSE

Hip joint effusion is expected in rapidly destructive osteoarthritis, a diagnosis often only made retrospectively at the end stage of the disease. This study assesses whether the presence of an effusion identified during routine ultrasound-guided hip injection may suggest a more aggressive process such as rapidly destructive osteoarthritis.

METHODS

After the observation of 10 index cases of rapidly destructive osteoarthritis in patients who presented with a joint effusion on ultrasound, we retrospectively reviewed 94 hips from 89 patients who underwent ultrasound-guided hip injection for pain. Preinjection longitudinal ultrasound images of the anterior capsule adjacent to the femoral neck and inferior to the femoral head were reviewed to determine if a joint effusion was present and the size of the effusion if one was there. Comparison of effusion size was then made between those hips that had a clinical and radiographic diagnosis of osteoarthritis and those who had rapidly destructive osteoarthritis by comparing the severity of joint effusion, if one was present.

RESULTS

Patients with rapidly destructive osteoarthritis were more likely to have a large joint effusion 60% (3/5) than were those with osteoarthritis 6.7% (6/89) (p = 0.013).

CONCLUSIONS

Large joint effusions identified sonographically correlate well with radiographic findings of rapidly destructive osteoarthritis. Given rapid onset and severity of the disease, when a large joint effusion is identified on routine hip intervention, patients should be forewarned of the potential for this disease process.

Evaluation of synovial inflammation in juvenile idiopathic arthritis by power color Doppler and Spectral Doppler ultrasonography

OBJECTIVES

To compare Power Color Doppler and Spectral Doppler ultrasonography indices (Resistive index and color fraction) in cases of Juvenile Idiopathic Arthritis (JIA) with healthy controls and evaluate their correlation with clinical and laboratory parameters.

METHODS

A cross sectional study was done over a period of 16 mo. Thirty patients of JIA and 30 age and sex matched healthy children were enrolled. Swelling and tenderness scores were evaluated and hemoglobin, total leukocyte count, erythrocyte sedimentation rate and C-reactive protein were done. A total of 112 diseased joints and 135 healthy joints were evaluated by USG by the same radiologist, and color fraction and RI were recorded.

RESULTS

Statistically significant higher color fraction and lower RI (Resistive Index) were found in diseased joints as compared to healthy joints. Also the value of color fraction increased significantly with increasing grade of tenderness and RI decreased significantly with increasing grade of swelling.

CONCLUSIONS

Power Color Doppler and Spectral Doppler ultrasonography (USG) indices (RI and color fraction) are significantly different in JIA patients. These might find a place in early diagnosis, monitoring of disease activity and response to therapy in JIA patients.

The value of hip aspiration in pediatric transient synovitis

INTRODUCTION

Hip transient synovitis (TS) is a common pediatric orthopaedic problem. Although a self-limiting illness, it often makes the patient temporarily disabled and poses a diagnostic difficulty because of its similarity to septic arthritis in clinical manifestations. The aim of this study was to evaluate the use of a single ultrasound-guided hip aspiration as a treatment modality for TS.

METHODS

Between the years 1984 and 1989, 112 children with TS were treated through bed rest and using nonsteroidal anti-inflammatory drugs (group 1). Between the years 1990 and 1999, 119 children diagnosed with TS were treated using hip aspiration, bed rest, and nonsteroidal anti-inflammatory drugs (group 2). Recovery parameters were compared between these patient groups.

RESULTS

Twenty-four hours after admission, limping was noted in 92% and 10% of the patients in groups 1 and 2, respectively, (P < 0.001). Refusal to bear weight was observed in 14% and 1% in groups 1 and 2, respectively, (P < 0.001), and hip joint pain was reported in 81% and 6% in groups 1 and 2, respectively, (P < 0.001). Larger joint effusions were found to be the reason behind the inability to bear weight.

CONCLUSIONS

Pain due to TS may be because of capsule stretching owing to the accumulation of joint effusion. Ultrasound-guided hip aspiration relieves pain and limitation in movement and provides rapid differential diagnosis from septic arthritis of the hip joint.

Association of hip joint effusion volume with early osteonecrosis of the femoral head

This study aimed to examine the association between hip joint effusion volume and osteonecrosis of the femoral head (ONFH) using the Association Research Circulation Osseous (ARCO) classification. Patients (n = 403) who were diagnosed with ONFH were enrolled between February 2005 and December 2008. Only patients (n = 109) with complete clinical and imaging data and at early to mid ARCO stage (I - III) were eligible for further analysis, including 94 males and 15 females. All the included patients had hip joint radiographic examinations (anteroposterior and frog-leg views) and magnetic resonance imaging scans (axial and coronal views). Out of 109 patients included in this study, 185 hip joints were involved (unilateral disease in 33 patients and bilateral diseases in 76 patients). The patients had a mean age of 39 ± 11 years (range, 13-70). All the affected hip joints exhibited effusion, classified as grade 1 (n = 70, 37.8%), grade 2 (n = 62, 33.5%), and grade 3 (n = 53, 28.7%). The volume of joint effusion varied significantly among stage I, II, and III (X2 = 29.210, P < 0.05). The effusion volume did not differ significantly among stage IIA, IIB, and IIC (X2 = 0.103, P > 0.05), whereas it differed significantly among stage IIIA, IIIB, and IIIC (X2 =11.556, P < 0.05). The volume of hip joint effusion was associated with the ARCO stage, and increased over the staging.

Hip radiography for the investigation of nontraumatic, short duration hip pain presenting to a children's emergency department

OBJECTIVE

To assess the diagnostic accuracy of routine hip x-ray in 2- to 11-year-old children presenting to the emergency department with recent onset, nontraumatic hip pain and to assess the predictive value of other clinical presenting variables.

METHODS

Retrospective chart review of children with hip pain of less than 2 weeks duration, presenting to a metropolitan children's emergency department in New Zealand. Data were extracted on radiography results, diagnosis on final discharge from hospital, and other clinical details. Diagnostic categories were divided into urgent pathology (those requiring immediate treatment) and nonurgent pathology (those requiring follow up and those requiring no treatment or follow up). Contingency analysis and logistic regression were performed on variables to assess ability to predict urgent pathology.

RESULTS

Hip x-rays were performed in 99% of 310 eligible patients. Of these, 3% had some degree of significant abnormality reported on hip x-ray. Final diagnoses were transient synovitis in 86% of patients, osteomyelitis or other significant musculoskeletal sepsis in 8%, slipped upper femoral epiphysis in 1%, and other musculoskeletal disorder in 4%, with no cases of septic arthritis. In children 9 years or older, the likelihood ratio with a positive x-ray was 17, compared with 6 in children younger than 9 years. Fever, weight-bearing status, and age were the most important predictors of urgent pathology.

CONCLUSIONS

In children younger than 9 years presenting with recent onset, nontraumatic hip pain, hip x-ray is of limited value. In children 9 years or older, hip x-ray may be useful to exclude slipped upper femoral epiphysis. Fever, weight bearing status, and age may better predict urgent pathology.

[Benefit of hip ultrasound in management of the limping child]

OBJECTIVE

To evaluate the contribution of sonography of the hip in the management of nontraumatic limping in children.

PATIENTS AND METHODS

Prospective study including children consulting for nontraumatic limping (n=93). These children had a clinical examination, a biological and imaging workup (pelvis x-rays (n=88), initial sonograph of the hip (n=93), and follow-up sonograph of the hip (n=29)).

RESULTS

Ninety-three children (69 boys, 24 girls) aged from 10 months to 13 years (median, 4 years) were included and divided into two groups: The sensitivity and specificity of sonography in establishing a serious diagnosis was 57% and 59%, respectively.

CONCLUSION

The advantage of systematic hip sonography is challenged in this study because of low sensitivity and specificity. Its main advantage seems to be in its negative results, which prompt other investigations.

The role of pelvic magnetic resonance in evaluating nonhip sources of infection in children with acute nontraumatic hip pain

We retrospectively identified all children with acute hip pain who underwent pelvic magnetic resonance (MR). Children with septic hip or history of trauma were excluded; the remaining children with signs of infection (fever, >38 degrees C; leukocytosis, >12 x 10(9)/L; or elevated erythrocyte sedimentation rate [ESR], >30 mm/h) comprised the study group. Thirty-three children (9 girls; age, 0.8-15.8 years) were identified. On MR examination, 18 (55%) of 33 children had hip joint effusion, whereas 19 (58%) of 33 children had other abnormalities, including pyomyositis (n=15), osteomyelitis (n=12), and sacroiliitis (n=3). Staphylococcus aureus was cultured from 13 (68%) of these 19 children. Compared with MR, sensitivity for bone and soft tissue abnormalities was 30% for pelvic radiography (n=26) and 71% for bone scintigraphy (n=8). Elevated ESR (>30 mm/h) was the clinical finding that best predicted pelvic osteomyelitis or pyomyositis. Pelvic MR should be performed to rule out pelvic osteomyelitis or pyomyositis in children with acute hip pain, ESR of more than 30 mm/h, and no evidence of septic hip.

MR imaging of transient synovitis: differentiation from septic arthritis

BACKGROUND

Transient synovitis is the most common cause of acute hip pain in children. However, MR imaging findings in transient synovitis and the role of MR imaging in differentiating transient synovitis from septic arthritis have not been fully reported.

OBJECTIVE

To describe the MR findings of transient synovitis and to determine whether the MR characteristics can differentiate this disease entity from septic arthritis.

MATERIALS AND METHODS

Clinical findings and MR images of 49 patients with transient synovitis (male/female 36/13, mean age 6.1 years) and 18 patients with septic arthritis (male/female 10/8, mean age 4.9 years) were retrospectively reviewed.

RESULTS

MR findings of transient synovitis were symptomatic joint effusion, synovial enhancement, contralateral joint effusion, synovial thickening, and signal intensity (SI) alterations and enhancement in surrounding soft tissue. Among these, SI alterations and enhancement in bone marrow and soft tissue, contralateral joint effusion, and synovial thickening were statistically significant MR findings in differentiating transient synovitis from septic arthritis.

CONCLUSIONS

The statistically significant MR findings in transient synovitis are contralateral (asymptomatic) joint effusions and the absence of SI abnormalities of the bone marrow. It is less common to have SI alterations and contrast enhancement of the soft tissues. The statistically significant MR findings in septic arthritis are SI alterations of the bone marrow, and SI alterations and contrast enhancement of the soft tissue. Ipsilateral effusion and synovial thickening and enhancement are present in both diseases.

The role of ultrasound in differentiating septic arthritis from transient synovitis of the hip in children

A total of 154 children admitted with septic arthritis (n=81) or transient synovitis (n=73) were studied retrospectively. Ultrasound findings for 127 patients were correlated with the final diagnosis. Sensitivity, specificity and positive predictive value of ultrasound for the diagnosis of pediatric septic hip were 86.4, 89.7 and 87.9%, respectively. Unsatisfactory outcome occurred more significantly in children, for whom treatment was initiated more than 4 days after the onset of symptoms and those who had a false-negative ultrasound study. Ultrasound cannot be used safely to distinguish between pediatric septic hip and transient synovitis. It may be a method of value to detect minimal hip effusion. A predictive algorithm using clinical, laboratory and ultrasound findings could be beneficial.

The limping child

A limp suggests an underlying pathology causing the abnormal gait pattern. There is a long list of possible causes. The challenge for the physician is to identify the cause and act accordingly. The purpose of this article is to instruct on the assessment of a child with a limp.

Evaluation of joint effusion in rabbits by color Doppler, power Doppler, and contrast-enhanced power Doppler ultrasonography

PURPOSE

The aim of this prospective study was to evaluate the diagnostic value of power Doppler ultrasonography (PDUS) and contrast-enhanced PDUS (CEPDUS) in the depiction and characterization of experimentally induced arthritis in the rabbit.

MATERIALS AND METHODS

Thirty rabbits were divided into three groups consisting of one control group (saline injection group) and two experimental groups: a suppurative arthritis group and a chemically induced synovitis group. The same amount (1 ml) of each agent was directly injected into the right hip joint. Serial color Doppler ultrasound (CDUS), PDUS, and CEPDUS images were obtained before and after injection.

RESULTS

We observed that all of the infected knees in the suppurative arthritis group with Staphylococcus aureus demonstrated an increased signal on PDUS after inoculation. A minimal power Doppler signal was presented in the chemically induced synovitis group with talc injection, but none of the control knees demonstrated any increased signals. CEPDUS was the most sensitive imaging modality for evaluating the increase of blood flows in suppurative arthritis and was subsequently followed by PDUS and CDUS.

CONCLUSION

The increased signals obtained with PDUS represent increased local blood flows; therefore, this technique can be used for evaluating the degree of inflammation. Furthermore, using the contrast agent enhances the sensitivity of PDUS, and it can even be useful for differentiating borderline cases.

Review article: diagnostic ultrasonography: applications in orthopaedic surgery

Diagnostic ultrasonography of musculoskeletal diseases in the United States has been used most often for detection of rotator cuff tears or developmental dysplasia of the hip. Diagnostic ultrasonography also is useful in imaging the periarticular soft tissues about the knee, hip, ankle, occult pediatric fractures, muscle injury, bone healing, and foreign bodies. Recent technologic improvements have made this imaging modality increasingly more accurate while providing significant benefits over traditional modalities such as magnetic resonance imaging, particularly regarding cost, patient satisfaction, and ease of usage. Increasing use in the future of diagnostic ultrasonography for musculoskeletal conditions is likely as acceptance grows. This review focuses on recent, practical applications of diagnostic ultrasonography of the musculoskeletal system.

Ultrasound in pediatric musculoskeletal disease: techniques and applications

The increased ratio of nonossified cartilage to bone in children makes ultrasound (US) a particularly suitable technique for evaluating pediatric musculoskeletal disorders. US allows the examiner to compare quickly and meticulously an affected to unaffected area of interest in different orthogonal planes without a need for sedation. Developmental dysplasia of the hip is the most common indication for pediatric musculoskeletal US. Sonography is also a cost-effective, useful, and complementary imaging tool for evaluating pediatric musculoskeletal trauma, inflammation-infection, and masses.

Review article: Paediatric bone and joint infection

Paediatric musculoskeletal infection remains an important cause of morbidity. Methicillin sensitive Staphylococcus aureus is still the most common organism although the incidence of methicillin resistant S. aureus in the community is rising. Osteomyelitis and septic arthritis due to Haemophilus influenzae is decreasing in incidence secondary to immunisation and in some units has been replaced by infections with the gram negative bacillus, Kingella kingae. Recent prospective studies indicate that uncomplicated osteomyelitis can be treated by three to four weeks of antibiotics. However, there is still a small group of children who will have overwhelming disseminated infection. These children require aggressive surgical and medical intervention. Two recent reports have identified an increased incidence of septic arthritis in children who have hemophilia and are HIV positive.

Targeted musculoarticular sonography in the detection of joint effusions

This article describes an advanced application for an established technology, specifically the use of bedside sonography in the assessment of the acutely painful joint in the emergency department. The sonographic windows for each of the axial synovial joints are outlined, with a brief discussion of commonly encountered pathologic conditions.

The limping child: evaluation and diagnosis

A limp is a common reason for a child to present to the orthopaedist. Because of the long list of potential diagnoses, some of which demand urgent treatment, an organized approach to evaluation is required. With an understanding of normal and abnormal gait, a directed history and physical examination, and the development of a differential diagnosis based on the type of limp, the patient's age, and the anatomic site that is most likely affected, the orthopaedist can take a selective approach to diagnostic testing. Laboratory tests are indicated when infection, inflammatory arthritis, or a malignant condition is in the differential diagnosis. The C-reactive protein assay is the most sensitive early test for musculoskeletal infections; an abnormal value rapidly returns to normal with effective treatment. Imaging should begin with plain radiography. Ultrasonography is particularly valuable in assessing the irritable hip and guiding aspiration, if necessary.

The Role of Ultrasound in the Diagnosis of Joint Hip Effusions in Small Children

There are a variety of causes for hip pain in children, including slipped capital femoral epiphysis (SCFE), toxic synovitis, septic arthritis, Perthes disease, fracture, and juvenile rheumatoid arthritis. Several of these processes can result in hip joint effusions. Although radiography is initially performed and is often diagnostic, the plain radiograph may be normal in the presence of a small joint effusion. Sonography can be used to determine whether an effusion is present and when deemed clinically appropriate, to guide a diagnostic or therapeutic arthrocentesis. When patients show signs of sepsis and effusion, an ultrasound-guided arthrocentesis can help differentiate between septic arthritis and toxic synovitis. In the evaluation of difficult cases, a bone scan or magnetic resonance imaging may be helpful to exclude the possibility of underlying osteomyelitis.

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.

Infection: ultrasound-guided procedures

The majority of fluid collections in the musculoskeletal system can be localized and aspirated under ultrasound guidance. Whether fluid is infected cannot be determined from ultrasound appearances and laboratory analysis is required. In complicated infection, particularly septic arthritis and osteomyelitis, combined use of MR imaging and aspiration under ultrasound is very useful.

Applications of musculoskeletal sonography

To successfully examine the musculoskeletal system sonographically, one must understand the normal musculoskeletal anatomy and function and be aware of the abnormal processes that affect the musculoskeletal structures. The goal of this review article is to provide a systematic approach to sonographic examination of the musculoskeletal system. The general sonographic appearances of normal and abnormal muscles, tendons, ligaments, bursae, and nerves are reviewed. The article then applies this general information to specific clinical applications by reviewing the normal anatomy of and specific pathologic conditions that affect the shoulder, elbow, hand, wrist, hip, knee, ankle, and foot.

Septic arthritis versus transient synovitis at MR imaging: preliminary assessment with signal intensity alterations in bone marrow

PURPOSE

To find any differential magnetic resonance (MR) imaging findings between septic arthritis and transient synovitis in pediatric patients.

MATERIALS AND METHODS

The MR imaging findings in nine pediatric patients with septic arthritis and 14 with transient synovitis were retrospectively studied. The diagnoses were made by means of joint aspiration with bacteriologic study, arthrotomy, and clinical evaluation. MR imaging findings were analyzed with emphasis on the grade of joint effusion and alterations in signal intensity in the soft tissue and bone marrow of the affected hip joint.

RESULTS

Signal intensity alterations in bone marrow (i.e., low signal intensity on fat-suppressed gadolinium-enhanced T1-weighted spin-echo images and high signal intensity on fat-suppressed T2-weighted fast spin-echo images) were seen in eight of nine patients with septic arthritis. These signal intensity alterations consisted of mild juxtaarticular changes in six patients without osteomyelitis and extensive changes in the femoral head and neck in two patients with coexistent osteomyelitis. Signal intensity alterations in bone marrow were not seen in the 14 patients with transient synovitis.

CONCLUSION

Signal intensity alterations in the bone marrow of the affected hip joint are useful in the differentiation of septic arthritis from transient synovitis.

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.

Imaging techniques in childhood arthritis

Technological advances in imaging have given physicians caring for children with arthritis a greater opportunity to detect abnormalities early in the course of a disease and better methods for monitoring chronic changes. Indications for using radiography, bone densitometry, nuclear medicine, ultrasound, CT scanning, and MR imaging are discussed in this article. In this era of managed care, the practicing clinician is urged more than ever to consult with the radiologist in selecting the study or sequence of studies to be used in particular case. In this way, evaluation can be limited to the most effective strategy from both the clinical and cost perspectives.

Hip pain in an adolescent

We have described a case of osteomyelitis of the ischium with extension into the adjacent soft tissues and abscess formation. Diagnosis and treatment were initially delayed due to the assumption that edema in the thigh muscles seen on initial MRI represented polymyositis. Subsequent radiographs demonstrated a destructive lesion containing a sequestrum within the ischium, indicative of osteomyelitis. It was, however, the MRI imaging that dramatically demonstrated the full extent of the complicating abscess which extended downward to mid-thigh and upward under the gluteal muscles almost to the top of the iliac crest. This proved to be an invaluable guide for the surgeon.