Objective In an effort to evolve semi-quantitative scoring methods based upon limitations identified in existing tools, integrating expert readers’ experience with all available scoring tools and the published data comparing the different scoring systems, we iteratively developed the MRI Osteoarthritis Knee Score (MOAKS). The purpose of this report is to describe the instrument and its reliability. Methods The MOAKS instrument refines the scoring of BMLs (providing regional delineation and scoring across regions), cartilage (sub-regional assessment), and refines the elements of meniscal morphology (adding meniscal hypertrophy, partial maceration and progressive partial maceration) scoring. After a training and calibration session two expert readers read MRIs of 20 knees separately. In addition, one reader re-read the same 20 MRIs 4 weeks later presented in random order to assess intra-rater reliability. The analyses presented here are for both intra- and inter-rater reliability (calculated using the linear weighted kappa and overall percent agreement). Results With the exception of inter-rater reliability for tibial cartilage area (kappa=0.36) and tibial osteophytes (kappa=0.49); and intra-rater reliability for tibial BML number of lesions (kappa=0.54), Hoffa-synovitis (kappa=0.42) all measures of reliability using kappa statistics were very good (0.61-0.8) or reached near perfect agreement (0.81-1.0). Only intra-rater reliability for Hoffa-synovitis, and inter-rater reliability for tibial and patellar osteophytes showed overall percent agreement < 75%. Conclusion MOAKS scoring shows very good to excellent reliability for the large majority of features assessed. Further iterative development and research will include assessment of its validation and responsiveness.

Change in synovitis was correlated with change in knee pain, but not loss of cartilage. Treatment of pain in knee osteoarthritis (OA) needs to consider treatment of synovitis.

Aim: MRI provides unparalleled visualization of all the anatomical structures involved in the osteoarthritis (OA) process. There is a need for reliable methods of quantifying abnormalities of these structures. The aim of this work was to assess the reliability of a novel MRI scoring system for evaluating OA of the knee and explore the validity of the bone marrow lesion (BML) scoring component of this new tool. Methods: After review of the relevant literature, a collaborative group of rheumatologists and radiologists from centers in the UK and USA established preliminary anatomical divisions, items (necessarily broadly inclusive) and scaling for a novel semi-quantitative knee score. A series of iterative reliability exercises were performed to reduce the initial items, and the reliability of the resultant Boston-Leeds Osteoarthritis Knee Score (BLOKS) was examined. A further sample had both the BLOKS and WORMS (Whole Organ MRI Score) BML score performed to assess the construct validity (relation to knee pain) and longitudinal validity (prediction of cartilage loss) of each scoring method. Results: The BLOKS scoring method assesses 9 intra-articular regions and contains 8 items, including features of bone marrow lesions, cartilage, osteophytes, synovitis, effusions and ligaments. The scaling for each feature ranges from 0-3. The inter-reader reliability for the final BLOKS items ranged from 0.51 for meniscal extrusion up to 0.79 for meniscal tear. The reliability for other key features was 0.72 for BML grade, 0.72 for cartilage morphology, and 0.62 for synovitis. Maximal BML size in BLOKS scale had a positive linear relation with VAS pain however the WORMS scale did not. Baseline BML was associated with cartilage loss on both BLOKS and WORMS scale. This association was stronger for BLOKS than WORMS. Conclusion:We have designed a novel scoring system for MRI OA knee, BLOKS, that demonstrates good reliability. Preliminary inspection of the validity of one of the components of this new tool supports the validity of the BLOKS BML scoring method over an existing instrument. Further iterative development will include validation for use in both clinical trials and epidemiological studies.

Background It has been suggested that synovitis causes joint pain. On non-contrast-enhanced MRIs synovial thickening cannot be assessed and on these images synovitis has been inconsistently associated with pain. Objective To assess synovial thickening in relation to knee pain severity among subjects in the Multicenter Osteoarthritis Study (MOST) using contrast-enhanced (CE) MRI. Methods MOST is a cohort study of people who have, or are at high risk of, knee osteoarthritis (OA). An unselected subset of 535 participants who volunteered underwent CE 1.5 T MRI of one knee. Synovitis was scored in six compartments and a summary score was created. Knee pain severity was assessed using the maximum item score on the Western Ontario and McMaster Osteoarthritis Index (WOMAC) pain scale. The association between synovitis and pain severity was examined using a logistic regression model adjusting for age, sex, body mass index (BMI), MRI bone marrow lesions and effusions in the whole sample and in a subgroup without radiographic OA. Results 454 of the 535 subjects undergoing CE MRI had complete data on synovitis and WOMAC pain. Mean age was 59 years, mean BMI 30 and 48% were women. In knees with moderate pain, 80% had synovitis. For knee pain, synovitis conferred a 9.2-fold increased odds compared with those without synovitis. In knees without radiographic OA (n=329), there was also an association of synovitis with an increased prevalence of pain. Conclusion Synovitis has a strong relation with knee pain severity, an association detected more clearly with CE MRI than suggested by previous studies using non-CE MRI measures of synovitis.

Although there is correlation between the histological and radiological features of intraosseous lipomas in general, some discrepancies occur in the radiological appearances of lipomas in different sites. The evidence that these lesions are true benign tumours of fat is controversial. Several aetiological factors have been implicated in their development. The constant location of os calcis lesions at the critical angle suggests an aetiology that may be related to biomechanical lines of stress. In other instances it is possible that involution of pre-existing lesions may lead to the development of lipomas.