Accuracy in detecting knee effusion with clinical examination and the effect of effusion, the patient's body mass index, and the clinician's experience

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.

Changes and Associations Between Gait Biomechanics and Knee Inflammation After Aspiration and Glucocorticoid Injection for Knee Osteoarthritis

OBJECTIVE

Although knee inflammation is thought to adversely affect joint function in patients with knee osteoarthritis (OA), the effects of reducing knee inflammation on gait biomechanics and strength are unknown. Our objectives were to compare ultrasound (US) measures of knee inflammation, gait biomechanics, knee extension and flexion strength, and pain before and after knee aspiration and glucocorticoid injection, and to explore associations among changes.

METHODS

Forty-nine patients (69 knees) with symptomatic knee OA and synovitis were tested before and 3-4 weeks after US-guided knee aspiration and glucocorticoid injection. At each visit, participants completed US assessments for inflammatory features of knee OA, 3D gait analysis, isokinetic knee extension and flexion strength tests, and Knee Osteoarthritis Outcome Score (KOOS) pain subscales. Linear and polynomial mixed-effects regression models were used to investigate changes and their associations.

RESULTS

Changes were observed for the synovitis score (unstandardized β [post-injection minus pre-injection] -0.55/9 [95% confidence interval (95% CI) -0.97, -0.12]), effusion depth (-1.05 mm [95% CI -1.07, -0.39]), KOOS pain (unstandardized β 5.91/100 [95% CI 1.86, 9.97]), peak external knee flexion and extension moments (KFM; 3.33 Nm [95% CI 0.45, 6.22]), KEM (-2.99 Nm [95% CI -5.93, -0.05]), and knee extension strength (4.70 Nm [95% CI 0.39, 9.00]) and flexion strength (3.91 Nm [95% CI 1.50, 6.81]). The external KFM increased during 13-38% and 76-89% of stance post-injection. When controlled for time, greater synovitis was associated with lower knee extension strength, while lower pain was associated with increased knee extension and flexion strength.

CONCLUSION

In patients with knee OA and synovitis, reduced inflammation and pain after aspiration and glucocorticoid injection are associated with changes in knee gait biomechanics and strength.

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.

Are OMERACT Knee Osteoarthritis Ultrasound Scores Associated With Pain Severity, Other Symptoms, and Radiographic and Magnetic Resonance Imaging Findings?

OBJECTIVE

To investigate the associations of Outcome Measures in Rheumatology (OMERACT) ultrasound scores for knee osteoarthritis (OA) with pain severity, other symptoms, and OA severity on radiographs and magnetic resonance imaging (MRI).

METHODS

Participants with symptomatic and mild to moderate radiographic knee OA underwent baseline dynamic ultrasound (US) assessment according to standardized OMERACT scanning protocol. Using the published US image atlas, a physician operator obtained semiquantitative or binary scores for US pathologies. Clinical severity was measured on numerical rating scale (NRS) and Knee Injury and Osteoarthritis Outcome Score (KOOS) symptoms and pain subscores. OA severity was assessed using the Kellgren-Lawrence (KL) grade on radiographs and MRI Osteoarthritis Knee Score (MOAKS) on noncontrast-enhanced MRI. Separate linear regression models were used to determine associations of US OA pathologies with pain and KOOS subscores, and Spearman correlations were used for US scores with KL grade and MOAKS.

RESULTS

Eighty-nine participants were included. Greater synovial hypertrophy, power Doppler (PD), and meniscal extrusion scores were associated with worse NRS pain [β 0.92 (95% CI 0.25-1.58), β 0.73 (95% CI 0.11-1.35), and β 1.01 (95% CI 0.22-1.80), respectively]. All greater US scores, except for cartilage grade, demonstrated significant associations with worse KOOS symptoms, whereas only PD and meniscal extrusion were associated with worse KOOS pain. All US scores, except for PD, were significantly correlated with KL grade. US pathologies, except for cartilage, revealed moderate to good correlation with their MOAKS counterparts, with US synovitis having the greatest correlation (0.69, 95% CI 0.60-0.78).

CONCLUSION

OMERACT US scores revealed significant associations with pain severity, KL grade, and MOAKS.

Association of Knee Effusion Detected by Physical Examination With Bone Marrow Lesions: Cross-Sectional and Longitudinal Analyses of a Population-Based Cohort

OBJECTIVE

To determine the association of effusion detected by physical examination with the prevalence of bone marrow lesions (BMLs) on magnetic resonance imaging (MRI), and the incidence/progression of BMLs over 3 years in subjects with knee osteoarthritis.

METHODS

A population-based cohort with knee pain (n = 255) was assessed for effusion on physical examination. On MRI, BMLs were graded 0-3 (none, mild, moderate, severe), and incidence/progression was defined as a worsening of the sum of BML scores over 6 surfaces by ≥1 grade. We analyzed the full cohort and a mild disease subsample with a Kellgren/Lawrence (K/L) grade <3. Cross-sectional logistic and longitudinal exponential regression analyses were performed, adjusted for age, sex, body mass index (BMI) and pain. We calculated sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for effusion detected by physical examination versus BMLs (prevalence and incidence/progression).

RESULTS

The weighted mean age was 56.7 years, the mean BMI was 26.5, 56.3% were women, 20.1% had effusion on physical examination, and 80.7% had a K/L grade <3. Effusion on physical examination was significantly associated with prevalent BMLs in the full cohort (odds ratio [OR] 6.10 [95% confidence interval (95% CI) 2.77-13.44]) and in the K/L grade <3 cohort (OR 6.88 [95% CI 2.76-17.15]). In the full cohort, sensitivity, specificity, PPV, and NPV were 34.6, 92.5, 79.9, and 62.1%, respectively, and in the K/L <3 cohort 31.7, 94.0, 75.5, and 70.1%, respectively. Longitudinally, effusion on physical examination was not significantly associated with BML incidence/progression in the full cohort (hazard ratio [HR] 1.83 [95% CI 0.95-3.52]) or in the K/L grade <3 cohort (HR 1.73 [95% CI 0.69-4.33]). In the two cohorts, sensitivity, specificity, PPV, and NPV were 32.0, 82.2, 42.2, and 74.9%, respectively, and 21.2, 85.6, 30.1, and 78.8% respectively.

CONCLUSION

BMLs on MRI can be predicted from physical examination effusion cross-sectionally, with a high PPV of 79.9%. Assessment for knee effusion on physical examination is useful for determining potential candidates with BMLs before costly MRI screening for recruitment into clinical trials.

Thresholds of ultrasound synovial abnormalities for knee osteoarthritis - a cross sectional study in the general population

OBJECTIVE

To establish "normal" ranges for synovial thickness and effusion detected by ultrasound (US) and to determine cut-offs associated with knee pain (KP) and radiographic knee osteoarthritis (RKOA) in the community.

METHODS

147 women and 152 men ≥40 years old were randomly selected from the Nottingham KP and Related Health in the Community (KPIC) cohort (n = 9506). The "normal" range was established using the percentile method in 163 participants who had no KP and no RKOA. Optimal (maximum sensitivity and specificity) and high specificity (90%) cut-offs were established using receiver operating characteristic (ROC) curve analysis in a comparison between people with both KP and RKOA and normal controls.

RESULTS

Effusion and synovial hypertrophy differed by gender but not by age or laterality, therefore gender-specific reference limits were estimated. However, the "normal" ranges between men and women were similar for effusion (0-10.3 mm vs 0-9.8 mm), but different for synovial hypertrophy (0-6.8 mm vs 0-5.4 mm). Power Doppler Signal (PDS) in the healthy controls was uncommon (1.2% in men and 0.0% in women). The optimal cut-off was 7.4 mm for men and 5.3 mm for women for effusion, and 3.7 and 1.6 for hypertrophy respectively. The high specificity cut-off was 8.9 for men and 7.8 for women for effusion, and 5.8 and 4.2 for hypertrophy respectively.

CONCLUSIONS

US effusion and synovial hypertrophy but not PDS are common, but differ by gender, in community-derived people without painful knee OA. Currently used cut-offs for abnormality need reappraisal.

Diagnostic performance of knee physical exam and participant-reported symptoms for MRI-detected effusion-synovitis among participants with early or late stage knee osteoarthritis: data from the Osteoarthritis Initiative

OBJECTIVE

Evaluate the diagnostic performance of knee physical exam findings and participant-reported symptoms for MRI-detected effusion-synovitis (ES) among knees with early and late-stage osteoarthritis (OA).

DESIGN

The Osteoarthritis Initiative (OAI) is a longitudinal study of participants with or at risk for knee OA. Two samples with MRI readings were available: 344 knees with early OA (312 participants) and 216 with late-stage OA (186 participants). Trained examiners performed bulge sign (BS) and patellar tap (PT) exams, and participants reported on knee swelling and pain with leg straightening. Effusion-synovitis on 3T non-contrast MRI was scored using the MRI Osteoarthritis Knee Score (MOAKS). Diagnostic performance of physical exam findings and symptoms was estimated with bootstrapped confidence intervals.

RESULTS

For the early OA sample, the highest sensitivity for medium/large effusion-synovitis was achieved with a positive finding for any of the physical exam maneuvers and/or participant-reported symptoms (81.0 [95% CI: 70.0, 91.3]). Both knee symptoms in combination had a prevalence of 11.7% and yielded the highest estimated positive predictive value (PPV) (50.0 [95% CI: 34.2, 66.7]) and likelihood ratio positive (LR+) (5.2 [95% CI: 2.9, 9.7]). In late-stage OA knees, exam findings and symptoms provided minimal information beyond the prevalence.

CONCLUSION

Patient report of both symptoms, or at least one positive exam finding and at least one symptom, could be used to identify knees at increased risk of effusion-synovitis in knees with early stage OA, either for screening purposes in clinical evaluation, or for study sample enrichment with an inflammatory phenotype; diagnostic performance was not sufficiently high for clinical diagnostic purposes.

Validation of two simple, objective tools for the assessment of synovial swelling in the equine fetlock region

Simple objective assessment tools are essential to monitor the efficacy of therapeutic interventions used in clinical settings. The purpose of present study was to investigate different ways of assessing synovial swelling of the equine fetlock region: tape measure and slide calliper, and to examine the method’s inter- and intra-examiner reliability. The hypotheses were that inter-examiner reliability would be fair and intra-examiner reliability strong. Measurements were performed on both hind limbs, on 16 horses. Palpation was done once for each limb, over the plantar pouch of the fetlock joint and the plantar digital flexor tendon sheath (PDFTS). Tape measure and slide calliper registrations were made, in triplicate by two independent assessors blinded to the measurements, horizontally over the fetlock joint and PDFTS areas, respectively. Intra-class correlation was used to measure inter- and intra-examiner reliability. The inter-examiner reliability was fair for the tape measurement of the plantar pouch of the fetlock joint, and almost perfect for the PDFTS. It was moderate for the slide calliper assessment of the PDFTS and almost perfect for the plantar pouch. The intra-examiner reliability was almost perfect for tape measure and slide calliper assessment, for the plantar pouch and PDFTS, respectively. Our results support our hypothesis and indicate that tape measure and slide calliper measurement of plantar pouch of the fetlock joint and PDFTS can be reliably performed by the same therapist. Slide calliper and circumference tape measures are promising objective techniques for assessing synovial swelling of the equine fetlock region.

High-resolution Sonographic Measurements of Lower Extremity Bursae in Chinese Healthy Young Men

Background:

Lower extremity bursae are very vulnerable to injury during strenuous physical exercises. Understanding the imaging characteristics of normal bursae is essential for early diagnosis of morphological abnormalities. Therefore, we evaluated the normal range of lower extremity bursae in healthy young men using high-resolution ultrasound (HR-US) imaging.

Methods:

Bursae in the lower extremities were examined by HR-US in 290 Chinese healthy young men with a median age of 18 years (range, 18–23 years). The bilateral suprapatellar bursa (SPB), deep infrapatellar bursa (DIPB), popliteal bursa (PB), and retrocalcaneal bursa (RCB) were imaged and measured for analysis.

Results:

The HR-US identification rates of the SPB, DIPB, PB, and RCB were 89.0% (517/580), 55.0% (319/580), 29.4% (171/580), and 49.5% (287/580), respectively. With the assumption that the bursae were normal in 95% of the study participants, the length and width values at the maximal cross-section of the SPB, DIPB, PB, and RCB were ≤18.00 and 6.09 mm, 8.10 and 2.11 mm, 7.67 and 3.93 mm, and 7.82 and 2.04 mm, respectively.

Conclusions:

Using HR-US imaging, we were able to analyze lower extremity bursae with high detection rates in healthy young men. The normal ranges of lower extremity bursa dimensions in healthy young men measured by HR-US in this study could be used as reference values for evaluation of bursa abnormalities in the lower extremity.

Interobserver and Intraobserver Reliability of Clinical Assessments in Knee Osteoarthritis

OBJECTIVE

Clinical examination of the knee is subject to measurement error. The aim of this analysis was to determine interobserver and intraobserver reliability of commonly used clinical tests in patients with knee osteoarthritis (OA).

METHODS

We studied subjects with symptomatic knee OA who were participants in an open-label clinical trial of intraarticular steroid therapy. Following standardization of the clinical test procedures, 2 clinicians assessed 25 subjects independently at the same visit, and the same clinician assessed 88 subjects over an interval period of 2-10 weeks; in both cases prior to the steroid intervention. Clinical examination included assessment of bony enlargement, crepitus, quadriceps wasting, knee effusion, joint-line and anserine tenderness, and knee range of movement (ROM). Intraclass correlation coefficients (ICC), estimated kappa (κ), weighted kappa (κω), and Bland-Altman plots were used to determine interobserver and intraobserver levels of agreement.

RESULTS

Using Landis and Koch criteria, interobserver κ scores were moderate for patellofemoral joint (κ = 0.53) and anserine tenderness (κ = 0.48); good for bony enlargement (κ = 0.66), quadriceps wasting (κ = 0.78), crepitus (κ = 0.78), medial tibiofemoral joint tenderness (κ = 0.76), and effusion assessed by ballottement (κ = 0.73) and bulge sign (κω = 0.78); and excellent for lateral tibiofemoral joint tenderness (κ = 1.00), flexion (ICC = 0.97), and extension (ICC = 0.87) ROM. Intraobserver κ scores were moderate for lateral tibiofemoral joint tenderness (κ = 0.60); good for crepitus (κ = 0.78), effusion assessed by ballottement test (κ = 0.77), patellofemoral joint (κ = 0.66), medial tibiofemoral joint (κ = 0.64), and anserine tenderness (κ = 0.73); and excellent for effusion assessed by bulge sign (κω = 0.83), bony enlargement (κ = 0.98), quadriceps wasting (κ = 0.83), flexion (ICC = 0.99), and extension (ICC = 0.96) ROM.

CONCLUSION

Among individuals with symptomatic knee OA, the reliability of clinical examination of the knee was at least good for the majority of clinical signs of knee OA.

Reliability of physical examination tests for the diagnosis of knee disorders: Evidence from a systematic review

Clinicians often rely on physical examination tests to guide them in the diagnostic process of knee disorders. However, reliability of these tests is often overlooked and may influence the consistency of results and overall diagnostic validity. Therefore, the objective of this study was to systematically review evidence on the reliability of physical examination tests for the diagnosis of knee disorders. A structured literature search was conducted in databases up to January 2016. Included studies needed to report reliability measures of at least one physical test for any knee disorder. Methodological quality was evaluated using the QAREL checklist. A qualitative synthesis of the evidence was performed. Thirty-three studies were included with a mean QAREL score of 5.5 ± 0.5. Based on low to moderate quality evidence, the Thessaly test for meniscal injuries reached moderate inter-rater reliability (k = 0.54). Based on moderate to excellent quality evidence, the Lachman for anterior cruciate ligament injuries reached moderate to excellent inter-rater reliability (k = 0.42 to 0.81). Based on low to moderate quality evidence, the Tibiofemoral Crepitus, Joint Line and Patellofemoral Pain/Tenderness, Bony Enlargement and Joint Pain on Movement tests for knee osteoarthritis reached fair to excellent inter-rater reliability (k = 0.29 to 0.93). Based on low to moderate quality evidence, the Lateral Glide, Lateral Tilt, Lateral Pull and Quality of Movement tests for patellofemoral pain reached moderate to good inter-rater reliability (k = 0.49 to 0.73). Many physical tests appear to reach good inter-rater reliability, but this is based on low-quality and conflicting evidence. High-quality research is required to evaluate the reliability of knee physical examination tests.

Synovial changes detected by ultrasound in people with knee osteoarthritis - a meta-analysis of observational studies

OBJECTIVES

To examine the prevalence of synovial effusion, synovial hypertrophy and positive Doppler signal (DS) detected by ultrasound (US) in people with knee osteoarthritis (OA) and/or knee pain compared to that in the general population.

METHOD

A systematic literature search was undertaken in Medline, EMBASE, Allied and Complementary Medicine, PubMed Web of Science, and SCOPUS databases in May 2015. Frequencies of US abnormalities in people with knee OA/pain, in the general population or asymptomatic controls were pooled using the random effects model. Publication bias and heterogeneity between studies were examined.

RESULTS

Twenty four studies in people with knee pain/OA and five studies of the general population or asymptomatic controls met the inclusion criteria. The pooled prevalence of US effusion, synovial hypertrophy and positive DS in people with knee OA/pain were 51.5% (95% CI 40.2 to 62.8), 41.5% (26.3-57.5) and 32.7% (8.34-63.24), respectively, which were higher than those in the general population or asymptomatic controls (19.9% (95%CI 7.8-35.3%), 14.5% (0-58.81), and 15.8 (3.08-35.36), respectively). People with knee OA (ACR criteria or radiographic OA) had greater prevalence of US abnormalities than people with knee pain (P = 0.037, P = 0.010 and P = 0.009, respectively).

CONCLUSIONS

US detected effusion, synovial hypertrophy and DS are more common in people with knee OA/pain, compared to the general population. These abnormalities relate more to presence of OA structural changes than to pain.

Clinical assessment of effusion in knee osteoarthritis-A systematic review

OBJECTIVE

The aim of this systematic review was to determine the validity and inter- and intra-observer reliability of the assessment of knee joint effusion in osteoarthritis (OA) of the knee.

METHODS

MEDLINE, Web of Knowledge, CINAHL, EMBASE, and AMED were searched from their inception to February 2015. Articles were included according to a priori defined criteria: samples containing participants with knee OA; prospective evaluation of clinical tests and assessments of knee effusion that included reliability, sensitivity, and specificity of these tests.

RESULTS

A total of 10 publications were reviewed. Eight of these considered reliability and four on validity of clinical assessments against ultrasound effusion. It was not possible to undertake a meta-analysis of reliability or validity because of differences in study designs and the clinical tests. Intra-observer kappa agreement for visible swelling ranged from 0.37 (suprapatellar) to 1.0 (prepatellar); for bulge sign 0.47 and balloon sign 0.37. Inter-observer kappa agreement for visible swelling ranged from -0.02 (prepatellar) to 0.65 (infrapatellar), the balloon sign -0.11 to 0.82, patellar tap -0.02 to 0.75 and bulge sign kappa -0.04 to 0.14 or reliability coefficient 0.97. Reliability and diagnostic accuracy tended to be better in experienced observers. Very few data looked at performance of individual clinical tests with sensitivity ranging 18.2-85.7% and specificity 35.3-93.3%, both higher with larger effusions.

CONCLUSION

The majority of unstandardized clinical tests to assess joint effusion in knee OA had relatively low intra- and inter-observer reliability. There is some evidence experience improved reliability and diagnostic accuracy of tests. Currently there is insufficient evidence to recommend any particular test in clinical practice.