Global ultrasound assessment of structural lesions in osteoarthritis: a reliability study by the OMERACT ultrasonography group on scoring cartilage and osteophytes in finger joints

Abstract

Objective Ultrasonography is sensitive for the evaluation of cartilage pathology and degree of osteophytes in patients with hand osteoarthritis (OA). High consistency of assessments is essential, and the OMERACT (Outcome Measures in Rheumatology) ultrasonography group took the initiative to explore the reliability of a global ultrasonography score in patients with hand OA using semiquantitative ultrasonography score of cartilage and osteophytes in finger joints. Methods Ten patients with hand OA were examined by 10 experienced sonographers over the course of two days. Semiquantitative scoring (0-3) was performed on osteophytes (carpo-metacarpal 1, metacarpo-phalangeal (MCP) 1-5, proximal interphalangeal 1-5 and distal interphalangeal 2-5 joints bilaterally with an ultrasonography atlas as reference) and cartilage pathology (MCP 2-5 bilaterally). A web-based exercise on static cartilage images was performed a month later. Reliability was assessed by use of weighted κ analyses. Results Osteophyte scores were evenly distributed, and the intraobserver and interobserver reliabilities were substantial to excellent (κ range 0.68-0.89 and mean κ 0.65 (day 1) and 0.67 (day 2), respectively). Cartilage scores were unevenly distributed, and the intraobserver and interobserver reliability was fair to moderate (κ range 0.46-0.66 and mean κ 0.39 (day 1) and 0.33 (day 2), respectively). The web-based exercise showed acceptable agreement for cartilage being normal (κ 0.47) or with complete loss (κ 0.68), but poor for the intermediate scores (κ 0.22-0.30). Conclusions Use of the present semiquantitative ultrasonography scoring system for cartilage pathology in hand OA is not recommended (while normal or total loss of cartilage may be assessed). However, the OMERACT ultrasonography group will endorse the use of semiquantitative scoring of osteophytes with the ultrasonography atlas as reference.

Ultrasonography of the metacarpophalangeal joints in healthy subjects using an 18 MHz transducer.

“…The presence of osteophytes characterize the hand osteoarthritis [29][30][31]. We found osteophytes in 7 joints but in the absence of other pathological findings, especially cartilage abnormalities, we could not interpret their presence as belonging to osteoarthritis.…”

Atlas-based knee osteophyte assessment with ultrasonography and radiography: relationship to arthroscopic degeneration of articular cartilage

“…With our tibiofemoral osteophyte atlas, agreement was lower than that of Mathiessen et al (5), with an average of 0.72 and 0.60 for intra-and inter-reader agreement, respectively. There is an obvious explanation for this because Mathiessen et al (5) had only two experienced readers whereas 14 readers were used in this study and 10 readers in the OMERACT study (14). More readers naturally induce more variation in average agreement results but they also increase the strength of the current study as the average agreement was still substantial.…”

“…Mathiessen et al (5) also reported very high intra-and inter-reader agreement for their hand osteophyte atlas from two experienced readers (mean κ values > 0.91) (5). In a recent Outcome Measures in Rheumatology (OMERACT) study, 10 patients with hand OA were examined by 10 experienced sonographers using the hand OA atlas (14). In that report, the intra-and interobserver reliabilities of osteophyte scores were substantial to excellent (κ = 0.68-0.89).…”

Imaging of osteoarthritis (OA): What is new?

“…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.…”