A systematic review of ultrasonography in osteoarthritis

BACKGROUND

Ultrasonography has been increasingly utilised to aid the understanding and management of rheumatic conditions. In recent years there has been a focus on the validity and utility of ultrasonography in demonstrating joint pathology, although this has largely focused on inflammatory arthritis.

AIMS

To undertake a systematic review of the published literature evaluating ultrasonography as an assessment tool in osteoarthritis.

METHODS

Medline and Pubmed were searched to identify original manuscripts, published before June 2008, utilising ultrasonography to assess the joints of cohorts of subjects with osteoarthritis. Data were extracted from manuscripts meeting the inclusion criteria, with a particular focus on the pathology imaged, the definitions used, scoring systems and their metric properties.

RESULTS

Forty-seven studies were identified that utilised ultrasonography to assess structural pathology in osteoarthritis. Doppler function was only assessed in 10 studies and contrast agents in one. There was heterogeneity with regard to the pathology examined, the definition of pathology, quantification and the reporting of these factors. There was also a lack of construct and criterion validity and data demonstrating reliability and sensitivity to change.

CONCLUSIONS

Whereas there is increasing evidence of the validity of ultrasonography in detecting structural pathology in inflammatory arthritis, more work is required to develop standardised definitions of pathology and to demonstrate the validity of ultrasonography in osteoarthritis.

A diagnostic algorithm for persistence of very early inflammatory arthritis: the utility of power Doppler ultrasound when added to conventional assessment tools

Objectives:

The aim of this study was to assess the value of power Doppler ultrasound (PDUS) in combination with routine management in a cohort of patients with very early inflammatory arthritis (IA).

Methods:

50 patients with ⩽12 weeks of inflammatory symptoms with or without signs had clinical, laboratory and imaging assessments. Diagnosis was recorded at 12 months. Assuming a 15% pre-test probability of IA, post-test probabilities for various assessments were calculated and used to develop a diagnostic algorithm.

Results:

All patients positive for rheumatoid factor (RF) and/or cyclic citrullinated peptide (CCP) developed persistent IA, so the added value of PDUS was assessed in the seronegative (RF and CCP negative) group. The probability of IA in a seronegative patient was 6%. The addition of clinical and radiographic features raised the probability of IA to 30% and, with certain ultrasound features, this rose to 94%.

Conclusions:

In seronegative patients with early IA, combining PDUS with routine assessment can have a major impact on the certainty of diagnosis.

Reliability of ultrasonography in detecting shoulder disease in patients with rheumatoid arthritis

Objective:

To assess the intra and interobserver reproducibility of musculoskeletal ultrasonography (US) among rheumatologists in detecting destructive and inflammatory shoulder abnormalities in patients with rheumatoid arthritis (RA) and to determine the overall agreement between US and MRI.

Methods:

A total of 14 observers examined 5 patients in 2 rounds independently and blindly of each other. US results were compared with MRI. Overall agreement of all findings, of positive findings on MRI, as well as intra and interobserver reliabilities, were calculated.

Results:

Overall agreement between US and MRI was seen in 79% with regard to humeral head erosions (HHE), in 64% with regard to posterior recess synovitis (PRS), in 31% with regard to axillary recess synovitis (ARS), in 64% with regard to bursitis, in 50% with regard to biceps tenosynovitis (BT), and in 84% for complete cuff tear (CCT). Intraobserver and interobserver κ was 0.69 and 0.43 for HHE, 0.29 and 0.49 for PRS, 0.57 and 1.00 for ARS, −0.17 and 0.51 for bursitis, 0.17 and 0.46 for BT and 0.52 and 0.6 for CCT, respectively. The intraobserver and interobserver κ for power Doppler (PD) was 0.90 and 0.70 for glenohumeral signals and 0.60 and 0.51 for bursal signals, respectively.

Conclusions:

US is a reliable imaging technique for most shoulder pathology in RA especially with regard to PD. Standardisation of scanning technique and definitions of particular lesions may further enhance the reliability of US investigation of the shoulder.

The optimal assessment of the rheumatoid arthritis hindfoot: a comparative study of clinical examination, ultrasound and high field MRI

OBJECTIVES

The aim of this pilot study was to compare clinical examination (CE) and ultrasound (US) with high field MRI (as the reference standard) for the detection of rearfoot and midtarsal joint synovitis and secondly tenosynovitis of the ankle tendons in patients with established rheumatoid arthritis (RA).

METHODS

Patients with RA (as determined by the modified American College of Rheumatology (ACR) criteria) with symptoms of midfoot and rearfoot disease were recruited. Demographic data were collected. All underwent CE, US and high field MRI (with intravenous gadolinium contrast) of their right foot. Percentage exact agreement (PEA), sensitivity and specificity were calculated for CE and US when compared to MRI. Inter-reader reliability for CE and US was also assessed.

RESULTS

Compared to the gold standard of MRI, for CE (joint synovitis) the ranges for sensitivity, specificity and PEA were 55-83%, 23-46% and 46-60%, and for US were 64-89%, 60-80% and 64-78%, respectively. Compared to the gold standard of MRI, for CE (tenosynovitis) the ranges for sensitivity, specificity and PEA were 0-100%, 20-91% and 55-91%, and for US were 0-67%, 86-100% and 59-86%, respectively.

CONCLUSION

CE was sensitive but US more specific in identifying hindfoot pathology in RA when compared to the reference standard of MRI. There was poor interobserver variability between ultrasonographers suggesting a need for standardisation of acquisition and interpretation of US images of the hindfoot.

Can ultrasonography improve on radiographic assessment in osteoarthritis of the hands? A comparison between radiographic and ultrasonographic detected pathology

OBJECTIVES

Ultrasonography (US) is used in rheumatology to assess small joints in inflammatory arthritis. Recently there has been some investigation into the utility of US in osteoarthritis (OA), however there has been little comparison of US to other imaging modalities in OA. This study aimed to compare the detection of osteophytosis and joint space narrowing (JSN) by US and conventional radiography (CR) in OA of the hand.

METHODS

SUBJECTS

with OA of the hand underwent US and CR examination of the small joints of both hands to identify osteophytosis and joint space narrowing.

RESULTS

1106 joints of 37 patients were imaged with US and CR. US detected osteophytosis in 448 joints, compared to CR that detected osteophytosis in 228 joints (approximately 30% fewer joints). Where osteophytosis was detected by US but not CR, this was usually proximal to the joint line. Joint space narrowing was detected in 450 joints by US, but only 261 joints by CR. The distribution of US and CR detected osteoarthritis changes in this cohort was consistent with population studies of radiographic hand OA, although metacarpophalangeal (MCP) involvement was higher than might be expected

CONCLUSIONS

US detected more osteophytosis and joint space narrowing than CR in OA of the hand. Involvement of MCP joints was more common than would be expected from population radiographic studies. The increased detection of OA structural pathology by US may make this a useful tool for hand OA research.

Recommendations for the content and conduct of European League Against Rheumatism (EULAR) musculoskeletal ultrasound courses

OBJECTIVE

To develop education guidelines for the conduct of future European League Against Rheumatism (EULAR) musculoskeletal ultrasound (MSUS) courses.

METHODS

We undertook a consensus-based, iterative process using two consecutive questionnaires sent to 29 senior ultrasonographer rheumatologists who comprised the faculty of the 14th EULAR ultrasound course (June 2007). The first questionnaire encompassed the following issues: type of MSUS educational model; course timing; course curriculum; course duration; number of participants per teacher in practical sessions; time spent on hands-on sessions; and the requirements and/or restrictions for attendance at the courses. The second questionnaire consisted of questions related to areas where consensus had not been achieved in the first questionnaire, and to the topics and pathologies to be assigned to different educational levels.

RESULTS

The response rate was 82.7% from the first questionnaire and 87.5% from the second questionnaire. The respondents were from 11 European countries. The group consensus on guidelines and curriculum was for a three-level education model (basic, intermediate and advanced) with timing and location related to the annual EULAR Congresses. The topics and pathologies to be included in each course were agreed. The course duration will be 20 h. There will be a maximum of six participants per teacher and 50-60% of total time will be spent on practical sessions. There was also agreement on prerequisite experience before attending the intermediate and advanced courses.

CONCLUSION

We have developed European agreed guidelines for the content and conduct of EULAR ultrasound courses, which may also be recommended to national and local MSUS training programmes.

The development of a preliminary ultrasonographic scoring system for features of hand osteoarthritis

OBJECTIVES

Painful osteoarthritis (OA) of the hand is common and a validated ultrasound (US) scoring system would be valuable for epidemiological and therapeutic outcome studies. US is increasingly used to assess peripheral joints, though most of the US focus in rheumatic diseases has been on rheumatoid arthritis. We aimed to develop a preliminary US hand OA scoring system, initially focusing on relevant pathological features with potentially high reliability.

METHODS

A group of experts in the fields of OA, US and novel tool development agreed on domains and suggested scaling of the items to be used in US hand OA scoring systems. A multi-observer reliability exercise was then performed to evaluate the draft items.

RESULTS

Synovitis (grey scale and Power Doppler) and osteophytes (representing activity and damage domains) were included and evaluated as the initial components of the scoring system. All three features were evaluated for their presence/absence and if present were scored using a 1-3 scale. The reliability exercise demonstrated intra-reader kappa values of 0.444-1.0, 0.211-1.0 and 0.087-1.0 for grey scale synovitis, power Doppler and osteophytes respectively. Inter-reader reliability kappa values were 0.398, 0.327 and 0.530 grey-scale synovitis, power Doppler and osteophytes respectively. Without extensive standardisation, both intra- and inter-reader reliability were moderately good.

CONCLUSIONS

The draft scoring system demonstrated substantive to almost perfect percentage exact agreement on the presence/absence of the selected OA features and moderate to substantive percentage exact agreement on semi-quantitative grading. This preliminary process provides a good basis from which to further develop an US outcome tool for hand OA that has the potential to be utilised in multicentre clinical trials.

The development of an evidence-based educational framework to facilitate the training of competent rheumatologist ultrasonographers

OBJECTIVES

Musculoskeletal ultrasonography (MSKUS) has been described by some rheumatologists as the 'stethoscope of the joint'. Such enthusiasm is supported by evidence confirming validity and clinical utility in evaluation of musculoskeletal diseases. But if rheumatologist-performed MSKUS is to emulate the impact of cardiologist-performed echocardiography, a number of educational challenges need be addressed. Evaluation of current training reveals the absence of a unified educational structure, ad hoc teaching and assessment and published data are insufficient to make practice and training recommendations specific to rheumatology.

METHODS

Informed by developments in adult-learning theory, we have utilized a competency-based approach to develop an educational programme for rheumatologist ultrasonographers. Fundamental to this process has been accurate functional analysis of the role of the rheumatologist ultrasonographer and precise translation of these data into educational outcomes. This involved a thorough, transparent, iterative, curriculum-defining approach, employing quantitative and qualitative research techniques including interview, questionnaire, Delphi and standard setting methodologies. All relevant stakeholders were engaged, including international US experts and clinical rheumatologists.

RESULTS

Outcomes include clarification of the role of a rheumatologist ultrasonographer; definition of appropriate knowledge and skills; establishment of competency standards; a balanced, clearly defined, clinically relevant educational outcome blueprint. Teaching and assessment approaches have been piloted as part of an accessible modular curriculum strategy. Thorough validation and evaluation confirms effectiveness, efficiency and suitability.

CONCLUSIONS

A comprehensive evidence-based, expert consensus-defined educational framework is proposed that provides a template for teaching and learning and standards for competency assessment. This should facilitate common principles of training, uniform professional practice and a justifiable governance structure.

The challenges of integrating ultrasonography into routine rheumatology practice: addressing the needs of clinical rheumatologists

OBJECTIVES

The practice of musculoskeletal ultrasonography (MSKUS) by UK rheumatologists remains limited, despite their reported enthusiasm. This study aimed to investigate factors that may encourage or limit future dissemination of rheumatologist-performed MSKUS and provide insights into perceived clinical importance and learning motivation relating to published recommendations by MSKUS experts.

METHODS

A written questionnaire study was conducted, involving 48 rheumatologists. Questions included the potential role of self-performed MSKUS, skills that they would be willing to learn and factors that may encourage or limit learning and practice. Competency recommendations proposed by imaging experts (142 skills in 7 anatomical areas) were reviewed, and quantitative and qualitative data collected regarding 'value to their practice' and 'learning motivation'.

RESULTS

Eighty-nine percent wished to learn MSKUS. Factors influencing learning and practice included time to achieve competency; relative-added clinical value of MSKUS examination; limited training infrastructure; access to existing imaging service; equipment funding. Skills offering greatest clinical utility were inflammatory arthritis assessment and guided procedures; least useful were evaluation of ligament/muscle lesions and soft tissue masses. There was a close correlation between clinical utility, learning motivation and competency standard.

CONCLUSIONS

A trade-off between added clinical value and time to achieve competency is the major factor influencing practice and training in MSKUS. Most rheumatologists report limited time to devote to training and therefore need to prioritize areas of importance for dedicated learning. Educational programmes need to be highly focused and relevant to clinical and job-plan requirements in order to encourage future dissemination of MSKUS practice by rheumatologists.

Finger tendon disease in untreated early rheumatoid arthritis: A comparison of ultrasound and magnetic resonance imaging

OBJECTIVE

To investigate the frequency and distribution of finger tenosynovitis in patients with early, untreated rheumatoid arthritis (RA) using gray-scale ultrasound (US) and magnetic resonance imaging (MRI).

METHODS

Fifty patients underwent US and MRI of metacarpophalangeal (MCP) joints 2-5. Twenty healthy controls underwent US only. Flexor and extensor involvement was documented for each joint. Intrareader reliability (IRR) was calculated by rereading static images.

RESULTS

Flexor tenosynovitis was found in 57 (28.5%) of 200 joints in 24 (48%) of 50 patients on US compared with 128 (64%) of 200 joints in 41 (82%) of 50 patients on MRI. Periextensor tenosynovitis was found in 14 (7%) joints in 9 (18%) patients on US compared with 80 (40%) joints in 36 (72%) patients on MRI. No controls had imaging tenosynovitis. Using MRI as the gold standard, the sensitivity, specificity, and negative and positive predictive values for US were 0.44, 0.99, 0.49, and 0.98, respectively, for flexor tenosynovitis and 0.15, 0.98, 0.63, and 0.86 for extensor tenosynovitis, respectively. The IRR was 0.85 and 0.8 for US and MRI, respectively. The most frequently involved joints on US and MRI were the second and third MCP joints.

CONCLUSION

This is the first study to compare US and MRI for the detection of tenosynovitis in the fingers of patients with early untreated RA. Tenosynovitis was found to be common using both modalities, with MRI being more sensitive. A negative US scan does not exclude inflammation and an MRI should be considered. Further work is recommended to standardize definitions and image acquisition for both US and MRI images.

Ultrasonography for rheumatologists: the development of specific competency based educational outcomes

BACKGROUND

A competency based approach to the education of rheumatologists in musculoskeletal ultrasonography (MSK US) ensures standards are documented, transparent, accountable, and defensible, with clear benefit to all stakeholders. Specific competency outcomes will facilitate informed development of a common curriculum and structured programme of training and assessment.

OBJECTIVE

To determine explicit competency based learning outcomes for rheumatologists undertaking MSK US.

METHODS

International experts in MSK US, satisfying specific selection criteria, were asked to define the minimum standards required by a rheumatologist to be judged competent in MSK US. They reviewed 115 MSK US skills, comprising bone and soft tissue pathology, in seven joints regions of the upper and lower limbs, and rated their relative importance according to specific criteria. These data are presented as specific educational outcomes within designated competency categories.

RESULTS

57 expert MSK US practitioners were identified and 35 took part in this study. Ten generic core competency outcomes were recognised including physics, anatomy, technique, and interpretation. Regarding specific regional competencies, 53% (61/115) were considered "must know" core learning outcomes, largely comprising inflammatory joint/tendon/bone pathology and guided procedures; 45% (52/115) were required at an intermediate/advanced level (18/115 "should know", 34/115 "could know"), and 2% (2/115) were deemed inappropriate/unnecessary for rheumatologist ultrasonographers.

CONCLUSIONS

This is the first study to developing a competency model for the education of rheumatologists in MSK US based on the evidence of international experts. A specific set of learning outcomes has been defined, which will facilitate future informed education and practice development and provide a blueprint for a structured rheumatology MSK US curriculum and assessment process.

Presence of significant synovitis in rheumatoid arthritis patients with disease-modifying antirheumatic drug–induced clinical remission: Evidence from an imaging study may explain structural progression

OBJECTIVE

More timely and effective therapy for rheumatoid arthritis (RA) has contributed to increasing rates of clinical remission. However, progression of structural damage may still occur in patients who have satisfied remission criteria, which suggests that there is ongoing disease activity. This questions the validity of current methods of assessing remission in RA. The purpose of this study was to test the hypothesis that modern joint imaging improves the accuracy of remission measurement in RA.

METHODS

We studied 107 RA patients receiving disease-modifying antirheumatic drug therapy who were judged by their consultant rheumatologist to be in remission and 17 normal control subjects. Patients underwent clinical, laboratory, functional, and quality of life assessments. The Disease Activity Score 28-joint assessment and the American College of Rheumatology remission criteria, together with strict clinical definitions of remission, were applied. Imaging of the hands and wrists using standardized acquisition and scoring techniques with conventional 1.5T magnetic resonance imaging (MRI) and ultrasonography (US) were performed.

RESULTS

Irrespective of which clinical criteria were applied to determine remission, the majority of patients continued to have evidence of active inflammation, as shown by findings on the imaging assessments. Even in asymptomatic patients with clinically normal joints, MRI showed that 96% had synovitis and 46% had bone marrow edema, and US showed that 73% had gray-scale synovial hypertrophy and 43% had increased power Doppler signal. Only mild synovial thickening was seen in 3 of the control subjects (18%), but no bone marrow edema.

CONCLUSION

Most RA patients who satisfied the remission criteria with normal findings on clinical and laboratory studies had imaging-detected synovitis. This subclinical inflammation may explain the observed discrepancy between disease activity and outcome in RA. Imaging assessment may be necessary for the accurate evaluation of disease status and, in particular, for the definition of true remission.

Hand bone loss in early undifferentiated arthritis: evaluating bone mineral density loss before the development of rheumatoid arthritis

OBJECTIVES

(1) To examine the change in regional bone mineral density (BMD), including the hands, and assess its role as a predictor of outcome in patients presenting with an early undifferentiated inflammatory arthritis; (2) to examine for associations with the changes in hand BMD.

METHODS

74 patients with undifferentiated hand arthritis of less than 12 months' duration were examined at baseline and then at three, six, and 12 months follow up, including BMD measurement of the femoral neck, spine (L2-4), and the whole hands using dual energy absorptiometry (DXA).

RESULTS

During the study, 13 patients were diagnosed as having rheumatoid arthritis, 19 as having inflammatory non-rheumatoid joint disorders, and 42 as having non-inflammatory joint disorders. At the femoral neck and lumbar spine no significant bone loss was seen in any of the three subgroups. At the 12 months follow up the mean (95% confidence interval) hand BMD loss in the patients with rheumatoid arthritis was -4.27% (-1.41 to -7.13); in the inflammatory non-rheumatoid group, -0.49% (-1.33 to +0.35); and in the non-inflammatory joint disorder group, -0.87% (-1.51 to -0.23). In a multivariate linear regression model (including age, rheumatoid factor, mean C reactive protein, mean HAQ score, and cumulative glucocorticoid dose), only mean C reactive protein (p<0.001) and rheumatoid factor (p = 0.04) were independently associated with change in hand BMD during follow up.

CONCLUSIONS

Hand DXA provides a very sensitive tool for measuring bone loss in early rheumatoid arthritis and may be useful in identifying patients at high risk of developing progressive disease. Further studies are needed to evaluate the role of hand bone loss as a prognostic factor and outcome measure in rheumatoid arthritis.

Interobserver reliability in musculoskeletal ultrasonography: results from a "Teach the Teachers" rheumatologist course

OBJECTIVE

To assess the interobserver reliability of the main periarticular and intra-articular ultrasonographic pathologies and to establish the principal disagreements on scanning technique and diagnostic criteria between a group of experts in musculoskeletal ultrasonography.

METHODS

The shoulder, wrist/hand, ankle/foot, or knee of 24 patients with rheumatic diseases were evaluated by 23 musculoskeletal ultrasound experts from different European countries randomly assigned to six groups. The participants did not reach consensus on scanning method or diagnostic criteria before the investigation. They were unaware of the patients' clinical and imaging data. The experts from each group undertook a blinded ultrasound examination of the four anatomical regions. The ultrasound investigation included the presence/absence of joint effusion/synovitis, bony cortex abnormalities, tenosynovitis, tendon lesions, bursitis, and power Doppler signal. Afterwards they compared the ultrasound findings and re-examined the patients together while discussing their results.

RESULTS

Overall agreements were 91% for joint effusion/synovitis and tendon lesions, 87% for cortical abnormalities, 84% for tenosynovitis, 83.5% for bursitis, and 83% for power Doppler signal; kappa values were good for the wrist/hand and knee (0.61 and 0.60) and fair for the shoulder and ankle/foot (0.50 and 0.54). The principal differences in scanning method and diagnostic criteria between experts were related to dynamic examination, definition of tendon lesions, and pathological v physiological fluid within joints, tendon sheaths, and bursae.

CONCLUSIONS

Musculoskeletal ultrasound has a moderate to good interobserver reliability. Further consensus on standardisation of scanning technique and diagnostic criteria is necessary to improve musculoskeletal ultrasonography reproducibility.

Interobserver reliability of rheumatologists performing musculoskeletal ultrasonography: results from a EULAR "Train the trainers" course

OBJECTIVE

To evaluate the interobserver reliability among 14 experts in musculoskeletal ultrasonography (US) and to determine the overall agreement about the US results compared with magnetic resonance imaging (MRI), which served as the imaging "gold standard".

METHODS

The clinically dominant joint regions (shoulder, knee, ankle/toe, wrist/finger) of four patients with inflammatory rheumatic diseases were ultrasonographically examined by 14 experts. US results were compared with MRI. Overall agreements, sensitivities, specificities, and interobserver reliabilities were assessed.

RESULTS

Taking an agreement in US examination of 10 out of 14 experts into account, the overall kappa for all examined joints was 0.76. Calculations for each joint region showed high kappa values for the knee (1), moderate values for the shoulder (0.76) and hand/finger (0.59), and low agreement for ankle/toe joints (0.28). kappa Values for bone lesions, bursitis, and tendon tears were high (kappa = 1). Relatively good agreement for most US findings, compared with MRI, was found for the shoulder (overall agreement 81%, sensitivity 76%, specificity 89%) and knee joint (overall agreement 88%, sensitivity 91%, specificity 88%). Sensitivities were lower for wrist/finger (overall agreement 73%, sensitivity 66%, specificity 88%) and ankle/toe joints (overall agreement 82%, sensitivity 61%, specificity 92%).

CONCLUSION

Interobserver reliabilities, sensitivities, and specificities in comparison with MRI were moderate to good. Further standardisation of US scanning techniques and definitions of different pathological US lesions are necessary to increase the interobserver agreement in musculoskeletal US.

New approaches to imaging early inflammatory arthritis

Imaging techniques such as musculoskeletal ultrasonography (MUS) and magnetic resonance imaging (MRI) are playing an increasingly important role in the assessment of patients with inflammatory arthritis. Such modalities are now used routinely in the evaluation of joint, tendon and soft tissue inflammation and bone damage in many early arthritis clinics. They have the ability to directly visualise, characterise and quantify the earliest inflammatory changes and have proved not only to be useful additional complimentary clinical tools to improve the speed and accuracy of diagnosis, direct appropriate treatment, monitor response to therapy, measure disease progression and outcome but also continue to contribute to our understanding of disease pathogenesis. These imaging methods may therefore offer a significant advantage as they endorse the principles of early diagnosis and optimal targeted therapy essential to providing the most favourable long term outcome for patients with inflammatory arthritis. This article reviews the current evidence supporting the role of MUS and MRI in the assessment of patients with inflammatory arthritis.

Should oligoarthritis be reclassified? Ultrasound reveals a high prevalence of subclinical disease

OBJECTIVE

To determine the prevalence of subclinical synovitis using ultrasound (US) imaging of both painful and asymptomatic joints, in patients with early (<12 months), untreated oligoarthritis (</=5 joints).

METHODS

Eighty patients underwent a detailed clinical assessment by two physicians. All painful joints were identified, which were immediately scanned by a sonographer. In the last 40 patients, an additional standard group of joints was scanned to establish the prevalence of synovitis in asymptomatic joints.

RESULTS

In 80 patients, 644 painful joints (with and without clinical synovitis) were identified and each underwent a US assessment. Of these joints, 185 had clinical synovitis, of which, US detected synovitis in only 79% (147/185). In the other 38 joints US demonstrated tenosynovitis instead of synovitis in 12 joints and possible, but not definite, synovitis in 11 joints. Fifteen joints were, however, normal on US. In 459 joints that were not clinically synovitic, US detected synovitis in 33% (150/459). In 64% (51/80) of patients, US detected synovitis in more joints than clinical examination and in 36% (29/80) of patients, US detected a polyarthritis (>6 joints). Of the 826 asymptomatic (non-painful) joints scanned, 13% (107/826) had US detected synovitis.

CONCLUSION

Sonography detected more synovitis than clinical examination in patients with oligoarthritis. In almost two thirds of patients there was evidence of subclinical disease while one third could be reclassified as polyarticular. These findings suggest that a definition of oligoarthritis based purely on clinical findings may be inappropriate, which may have important implications for disease management.

Validation and reproducibility of ultrasonography in the detection of synovitis in the knee: A comparison with arthroscopy and clinical examination

OBJECTIVE

Accurate detection of synovitis is important in both the diagnosis and outcome assessment of arthritis. This study was undertaken to assess the validity and reproducibility of ultrasonography (US) as a means of detecting synovitis in the knee, by comparing US findings with findings of arthroscopy and clinical examination.

METHODS

Sixty consecutive patients with knee pain due to various arthritides had a clinical examination and US of their knee performed immediately prior to arthroscopy. All 3 assessments were performed by different clinicians who were blinded to the results obtained with the other modalities. US and clinical examination were compared with arthroscopically detected synovitis as the gold standard. Data from a subset of patients were used for calculating the inter- and intrareader reproducibility of US results, using a standard dichotomous (absence/presence of synovitis) as well as a graded (absence/grade of synovitis) scoring system.

RESULTS

With the use of arthroscopy as the gold standard, US had a higher sensitivity (98% versus 85%), specificity (88% versus 25%), accuracy (97% versus 77%), positive predictive value (98% versus 88%), and negative predictive value (88% versus 20%) compared with clinical examination. The Cohen kappa values for inter- and intrareader reproducibility of US for distinguishing between presence and absence of synovitis were 0.71 and 0.85, respectively (P < 0.05 for both). The weighted kappa values for distinguishing grade of synovitis were 0.65 for inter- and 0.74 for intrareader reproducibility. The kappa value for intrareader reproducibility of arthroscopy results was 0.88.

CONCLUSION

Ultrasonography is a valid and reproducible technique for detecting synovitis in the knee, and is more accurate than clinical examination. It may be valuable as a tool in studies investigating pain, diagnosis, and treatment response in knee arthritis.