An OMERACT reliability exercise of inflammatory and structural abnormalities in patients with knee osteoarthritis using ultrasound assessment

Abstract

Objective To assess whether ultrasonography (US) is reliable for the evaluation of inflammatory and structural abnormalities in patients with knee osteoarthritis (OA). Methods Thirteen patients with early knee OA were examined by 11 experienced sonographers during 2 days. Dichotomous and semiquantitative scoring was performed on synovitis characteristics in various aspects of the knee joint. Semiquantitative scoring was done of osteophytes at the medial and lateral femorotibial joint space or cartilage damage of the trochlea and on medial meniscal damage bilaterally. Intra-and interobserver reliability were computed by use of unweighted and weighted κ coefficients. Results Intra-and interobserver reliability scores were moderate to good for synovitis (mean κ 0.67 and 0.52, respectively) as well as moderate to good for the global synovitis (0.70 and 0.50, respectively). Mean intra-and interobserver reliability κ for cartilage damage, medial meniscal damage and osteophytes ranged from fair to good (0.55 and 0.34, 0.75 and 0.56, 0.73 and 0.60, respectively). Conclusions Using a standardised protocol, dichotomous and semiquantitative US scoring of pathological changes in knee OA can be reliable.

Imaging of osteoarthritis (OA): What is new?

“…2) [66][67][68]. The cartilage of knee joints has a normal thickness of about 2 mm, and superficial regions can easily be evaluated by ultrasound [66]. However, in the small joints of the hands, there are conflicting results, with an important finding being that ultrasound may differentiate between normal and pathological finger joint cartilage, whereas semi-quantitative scoring is not reliable [69,70].…”

“…The reliability of ultrasound assessment of osteophytes has been studied in hand, hip and knee OA, and high intra-and inter-reader agreements have been reported [66,67,69]. Such good reliability suggests that ultrasound of osteophytes provide a responsive measure for follow-up in long-term studies.…”

“…Ultrasound has been found to be a sensitive imaging modality for detection of osteophytes, being as sensitive as MRI where it has good acoustic window and more sensitive than conventional radiography [24,34,72,80]. The size of osteophytes may also be scored to evaluate the severity of OA [66,81]. A recent study of knee joints showed a significant association between ultrasound of osteophytes and arthroscopic cartilage changes in the medial knee compartment, whereas this association was not found for CR [82].…”

“…altered echogenicity and thinning) in cross-sectional studies, primarily of large joints such as the knee (Fig. 2) [66][67][68]. The cartilage of knee joints has a normal thickness of about 2 mm, and superficial regions can easily be evaluated by ultrasound [66].…”

“…Ultrasound generally demonstrates low-grade inflammatory disease in OA, though some patients have severe synovitis. Ultrasound has for a long time been used to assess synovitis in the small joints of patients with rheumatoid arthritis (RA), and reliable scoring methods have been developed [66,71]. Synovitis found in OA joints has similar appearance as in RA, and has been assessed using scoring systems developed for RA patients [24,[72][73][74].…”