Joint effusion of the knee: potentialities and limitations of ultrasonography

Clinical examination, ultrasound assessment and aspiration of knee effusion in primary knee osteoarthritis patients

BACKGROUND

To assess the diagnostic performance of clinical examination and ultrasound (US) assessment of knee effusion in primary knee osteoarthritis (KOA) patients. Furthermore, the success rate for effusion aspiration and the factors related to it were investigated.

METHODS

This cross-sectional study included patients diagnosed with primary KOA-induced knee effusion clinically or sonographically. The affected knee of each patient was subjected to clinical examination and US assessment using the ZAGAZIG effusion and synovitis ultrasonographic score. Patients with confirmed effusion and consented to aspiration were prepared for direct US-guided aspiration under complete aseptic techniques.

RESULTS

One hundred and nine knees were examined. During visual inspection, swelling was detected in 80.7% of knees and effusion was confirmed by US in 67.8% of knees. Visual inspection was the most sensitive at 90.54% while bulge sign was the most specific at 65.71%. Only 48 patients (61 knees) consented to aspiration procedure; 47.5% had grade III effusion, and 45.9% had grade III synovitis. Successful aspiration was achieved in 77% of knees. Two needle types were used; a 22 gauge / 3.5-inch spinal needle in 44 knees and an 18 gauge/ 1.5-inch needle in 17 knees, with a success rate of 90.9% and 41.2%, respectively. Aspirated amount of synovial fluid correlated positively with effusion grade (r_s=0.455, p < 0.001) and negatively with synovitis grade on US (r_s = - 0.329, p = 0.01).

CONCLUSIONS

The superiority of the US over clinical examination in detecting knee effusion suggests that US should be used routinely to confirm the presence of effusion. Long needles (spinal needle) may have a higher success rate of aspiration than shorter needles.

Ultrasonography for quantitative assessment of knee joint effusions-useful tool for objective evaluation of rehabilitation progress?

PURPOSE

We sought to externally validate ultrasonography (US) for quantification of suprapatellar effusion size to improve diagnosis and individualised rehabilitation strategies in knee rehabilitation after anterior cruciate ligament reconstruction (ACLR) surgery.

METHODS

US was performed on 35 patients as part of the ongoing CAMOPED study. Data were collected in ACLR and post surgery in defined intervals up to one year post-operation. The palpatory assessment was graded using the International Knee Documentation Committee (oIKDC).

RESULTS

In a total of 164 sonographies, a strong correlation between palpatory and US effusion (r = 0.83, p < 0.01) with lower deviations in US quantification compared to palpatory quantification Y = 1.15 + 0.15* x was seen. Threshold values could be determined for the detection of effusions by palpation and for the differentiation between mild and moderate/severe effusions (effusion depth: 2.6 mm and resp. 5.8 mm, respectively).

CONCLUSIONS

As demonstrated in this multicenter study, the size of suprapatellar effusions can be easily quantified with high accuracy using standardised bedside ultrasound. Especially in moderate to severe effusions, US provides a practical and reliable tool for outcome measurement superior to palpatory assessment with the goal of optimising individual recommendations during the rehabilitation course. Furthermore, for the first time, it has been possible to define sonographic threshold values for the detection of effusion and differentiation of mild vs. moderate/severe effusion by means of palpation.

MRI and Sonography of the Knee in Acute Reactive Arthritis: An Observational Cohort Study

INTRODUCTION

Reactive arthritis (ReA) is a unique subgroup of spondyloarthritis with acute presentation and tendency to develop chronicity. Magnetic resonance imaging (MRI) has enabled identification of sensitive markers of response to therapy.

METHODS

A longitudinal pilot study of acute ReA with knee joint involvement satisfying the Braun's criteria was undertaken. Magnetic resonance imaging of the knee was assessed at baseline, and agreement with ultrasonography was assessed. Clinical details were recorded using a detailed and structured case record form. Patients were followed up, and MRI predictors of transition to chronic arthritis were looked for.

RESULTS

In 25 patients with ReA, synovial thickening was the most common feature. Enthesitis was observed on MRI in 20%. Urethritis-related and HLA-B27-positive ReA had higher synovial thickening scores (p = 0.007). Agreement was poor between MRI and ultrasonography (synovial hypertrophy: k = 0.04). On follow-up, 34% (n = 7/21 for >12 months) continued to have active disease. None of the clinical or radiological features were predictive of chronicity.

CONCLUSIONS

Posturethritis and B27-positive ReA was more severe than postenteritis ReA and RA on MRI. One third develop chronic disease on follow-up. Magnetic resonance imaging is superior to sonography, although baseline imaging is not predictive of chronicity. The results of this pilot exploratory study argue for larger studies on MRI in ReA.

Comparison of diagnostic accuracy of point-of-care ultrasonography and X-ray of bony injuries of the knee

PURPOSE

We aimed to compare the accuracy of point-of-care ultrasonography (POCUS) and X-ray (XR) in the diagnosis of knee bone fractures and fracture characteristics in cases of injuries to the knee.

METHODS

The study was conducted in the emergency department (ED) of a tertiary hospital between March 2017 and March 2019. It included patients who presented to the ED with isolated knee injuries, were suspected to have a bony lesion based on clinical examinations, and were ultimately referred for XR. Five emergency physicians (EPs) who had at least three years of ED experience participated in the study. Before the study, these EPs received training on knee examination and radiographic investigation of the knee joint. They were also trained on how to assess the knee joint using POCUS. The knee bones, patella, femur, tibia, and fibula were evaluated. A POCUS examination of the knee bones was carried out according to the eight-step Kozaci Protocol.

RESULTS

This study included 92 patients with knee trauma. The mean age of the patients was 34 ± 16 years (6-55 years). Using POCUS and XR, fractures were detected in 40 (43%) and 32 patients (35%), respectively. Relative to XR, for detecting fractures, POCUS showed sensitivity, specificity, positive predictive value, and negative predictive value of 97%, 85%, 78%, 98%, respectively, and the kappa value was 0.774. POCUS examination revealed hematoma and edema in the soft tissue in 34 (37%) patients and hemarthrosis in 33 patients (36%).

CONCLUSION

XR is the first and most widely used imaging modality to identify fractures of the knee bone trauma. However, POCUS examination can successfully diagnose bony lesions of the knee in patients with stable vital signs and without life-threatening injuries. It can also easily diagnose hematoma and hemarthrosis. Therefore, POCUS can be used as a diagnostic tool in emergency situations where XR is not available.

Agreement With Pediatric Suprapatellar Bursa Effusion Assessments by Point-of-Care Ultrasound After Remote Training

BACKGROUND

The ease of instruction for point-of-care ultrasound (POCUS) to detect suprapatellar bursa (SPB) effusions in pediatric patients is unknown. Considering in person limitations because of the coronavirus pandemic, strategies for POCUS education by remote learning are necessary.

METHODS

We crafted a 90-minute didactic training that was presented via a remote learning format. The main outcome of interest was the interobserver reliability of SPB effusion assessment by novice sonologists compared with POCUS faculty. Novice sonologists were pediatric emergency medicine (PEM) fellows. Pediatric emergency medicine fellows interpreted longitudinal SPB examinations obtained in our pediatric emergency department from July 2013 to June 2020. Assessments were performed 2 months after the remote training. Pediatric emergency medicine fellows had a limited experience performing these musculoskeletal scans and were blinded to POCUS faculty and each other's assessments. Interobserver reliability was assessed with Cohen κ coefficient. Second, we calculated test characteristics of knee radiography compared with PEM POCUS faculty determination of SPB effusion by ultrasound. We further explored how effusion size measured by POCUS impacted the diagnosis by knee radiography. A receiver operator characteristic curve of knee radiography diagnosis of SPB effusion was created using the maximal height of SPB effusion by POCUS as the predictor variable.

RESULTS

A total of 116 SPB scans in 71 patients were assessed. From this group, 70 scans were of affected knees and 46 scans were of contralateral, asymptomatic knees. The mean age of patients was 10 years and 46% were girl. The prevalence of SPB effusions was 42%. The κ coefficients between the 3 novice sonologists and POCUS faculty were 0.75 (0.62-0.87), 0.77 (0.65-0.89), and 0.83 (0.72-0.93) with 88%, 89%, and 91% agreement. Knee radiography exhibited an overall sensitivity of 65% (95% confidence interval [CI], 46-79%), specificity of 84% (95% CI, 60-97%), negative predictive value of 55% (95% CI, 43-66%), and positive predictive value of 88% (95% CI, 73-96%) to diagnose SPB effusions. The area under the receiver operator characteristic curve was 0.850. With an SPB height cutoff of 4 mm as true positives, radiography had a sensitivity of 81% and a specificity of 83%.

CONCLUSIONS

After a remote teleconference didactic session, PEM fellows were able to successfully diagnose SPB effusions using a longitudinal view with substantial interobserver reliability. Knee radiography exhibited limited sensitivity to rule out SPB effusions.

Diagnostic Utility of Ultrasound Versus Physical Examination in Assessing Knee Effusions: A Systematic Review and Meta-analysis

Knee effusion can be detected by physical examination, ultrasound and MRI, but the utility of each test is unclear. This study aimed to analyze the diagnostic value of physical examination and ultrasound for knee effusion. A systematic literature search of electronic databases was completed. Bivariate mixed-effects regression modelling was used to estimate sensitivity, specificity and diagnostic odds ratio of physical examination and ultrasound diagnosis of knee effusion. Sensitivity of ultrasound diagnosis of knee effusion was higher than the bulge sign and patellar tap, leading to improved positive and negative predictive values.

Ultrasound-Guided Talonavicular Arthrocentesis

BACKGROUND

Joint arthrocentesis is a commonly performed procedure by the emergency physician (EP). Point of care ultrasound (POCUS) has demonstrated promise in identifying joint effusions and guiding arthrocentesis procedures. EP-performed talonavicular joint arthrocentesis has not been previously described in the literature. We present a case in which an isolated talonavicular joint effusion was identified and then subsequently aspirated using POCUS.

CASE REPORT

A 65-year-old man presented with atraumatic right ankle pain. On arrival, he was noted to have diffuse warmth and edema around the ankle and midfoot. POCUS was performed to evaluate for an ankle joint effusion, which was not present. The ultrasound was then moved distally, where a talonavicular joint effusion was noted. Inflammatory markers were found to be elevated. A magnetic resonance imaging scan revealed an isolated talonavicular joint effusion without additional acute findings. POCUS was then used to perform an arthrocentesis, which revealed monosodium urate crystals consistent with an initial episode of gouty arthritis. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: POCUS provides the EP with an efficient tool to diagnose joint effusions and guide arthrocentesis procedures. The foot is composed of several small joints where ultrasound can be particularly helpful. Similar to the ankle joint, these joints can be afflicted with pyogenic infections and crystalline arthropathies. To our knowledge, we present the first report of EP-performed talonavicular arthrocentesis guided by POCUS. The approach to this joint and technique for arthrocentesis are presented.

Point of care ultrasound for rapid assessment and treatment of palliative care patients in acute medical settings

The combination of an ageing population with improving survival in malignant and non-malignant disease processes results in a growing cohort of patients with advanced or end-stage chronic diseases who require acute medical care. Emergency care has historically been stereotyped as the identification and treatment of acute life-threatening problems. Although palliative care may be considered to be new to the formal curriculum of emergency medicine, in many domains the ultrasound skillset of a physician in acute medical care can be efficaciously deployed the benefit of patients with both malignant and non-malignant disease processes that require palliative care in the full breadth of acute healthcare settings. In diagnostic domains (abdominal pain, urinary tract obstruction, dyspnoea, venous thromboembolism and musculoskeletal pain) and for specific intervention guidance (thoracentesis, paracentesis, venous access, regional anaesthesia and musculoskeletal interventions) we suggest that POCUS has the potential to streamline improve patient satisfaction, streamline diagnostic strategies, optimise patient length of stay, expedite timely symptomatic relief and reduce complications in this important patient population. POCUS is a mandatory competence in the European curriculum of internal medicine, and specific training programs which cover applications in the domains of palliative care in acute care settings are available. Supervision, quality assurance and appropriate documentation are required. We expect that as the availability of mobile units suitable for point of care applications increases, these applications should become standard of care in the acute management of patients who require palliative care.

Sonography of Knee Effusion

Objective:

A review of the anatomy of the synovial recesses of the knee is important to better understand the different effusion presentations, update the diagnosis criteria of knee effusion based on the measured synovial recesses and discuss the differentiation of some effused recesses from other lesions around the knee.

Method:

This review focuses on the anatomy of the synovial recesses of the knee and classifies them into three groups (anterior, parameniscal, and posterior recesses), as well as provides an overview on the etiology of knee effusion, its sonographic detection, and diagnosis criteria.

Results:

Knee effusion is a very common pathological finding in sonography of the knee. The unique joint structure of the knee provides the possibility to host complex synovial recesses. Fluid in some of the synovial recesses is valuable for the diagnosis of knee effusion, while in certain situations, some recesses may impose diagnostic uncertainty. Knowledge of these synovial recesses is essential to avoid diagnostic pitfalls.

Conclusion:

This review provides an important discussion of the differentiation of some recesses effusions from other lesions around the knee.

Ultrasound of iliotibial band syndrome

Iliotibial band syndrome or friction syndrome is an overuse disorder of the lateral knee. It is commonly reported in athletes, such as runners and cyclists, and refers to pain related to physical activity. The diagnosis is based on clinical history and physical assessment. Imaging, including ultrasound, is mainly performed in recurrent or refractory cases. The purpose of this paper is to review the etiology, diagnosis, and therapy of iliotibial band syndrome with a focus on ultrasound imaging and ultrasound-guided treatment. Ultrasound findings include soft-tissue edematous swelling or discrete fluid collection, suggestive of bursitis, between the iliotibial band and the lateral femoral epicondyle. The thickening of the iliotibial band has been inconsistently reported. Treatment varies according to the disease phase and, in the acute phase, consists of rest, physical therapy, and anti-inflammatory medications. Ultrasound-guided local steroid injections are effective in relieving symptoms.

Sonographic assessment of the anatomy and common pathologies of clinically important bursae

High-resolution ultrasonography has many advantages in the imaging of the musculoskeletal system, when compared to other imaging methods, particularly in superficial, easily accessible parts of the body. It is a perfect diagnostic tool for visualizing the most common pathologies of the musculoskeletal system, including the bursae. Inflammation of bursae is frequent, and it can mimic other diseases of the musculoskeletal system. Therefore, knowledge of normal ultrasound anatomy of the bursae, their exact location in the human body, and the sonographic signs of their most common pathologies is essential for establishing a quick and accurate diagnosis by ultrasound. Common conditions affecting bursae, leading to bursitis, include acute trauma, overuse syndromes, degenerative diseases, inflammatory conditions (rheumatoid arthritis, psoriatic arthritis, gout etc.), infections such as tuberculosis, synovial tumors and tumor-like conditions (pigmented villonodular synovitis, osteochondromatosis), and many more. This review article presents and explains ultrasound examples of the most frequent pathological conditions affecting bursae. Images include normal and pathological conditions of bursae around the shoulder joint, elbow, hip, knee, and ankle joint.

Comparison of X-Ray Imaging and Computed Tomography Scan in the Evaluation of Knee Trauma

Background and objectives: The aim of the study was to compare the accuracy of X-ray (XR) imaging according to computed tomography (CT) scanning in the diagnosis of knee bone fractures, and in the determination of fracture characteristics, and to identify CT scan indications in patients with knee trauma. Materials and methods: The patients who presented to the emergency department (ED) due to knee trauma between January 2017 and December 2018 and who underwent XR imaging and CT scans were included in the study. XR images were reinterpreted by an emergency physician. The official reports, which had been interpreted by a radiologist in the hospital automation system for CT images, were considered valid. Results: Five hundred and forty-eight patients were included in the study. Of the patients, 200 (36.5%) had fractures in XR imaging and 208 (38.0%) had fractures in CT scans. Compared to CT scanning, XR imaging was found to have 89% sensitivity, 95% specificity, 92% positive predictive value, and 92% negative predictive value in identifying the fracture. The sensitivity of XR imaging in identifying growth plate fracture, angulation, stepping off, and extension of the fracture into the joint space was determined as 78% and less. According to the kappa value, there was determined a perfect concordance between the XR imaging and CT scans in angulation, stepping off, and extension of the fracture into the joint space. This concordance was moderate in growth plate fractures. Conclusions: XR imaging has a low sensitivity in identifying knee fractures. There is a moderate concordance between XR imaging and CT scanning in identifying growth plate fractures. Therefore, CT scanning should be performed in patients whose fracture type and fracture characteristics are not able to be determined exactly with XR imaging in knee injury.