Ultrasound of knee osteoarthritis: interobserver agreement and correlation with Western Ontario and McMaster Universities Osteoarthritis

Abstract

The aim of this work was to assess the reproducibility of ultrasound findings of knee osteoarthritis and to correlate ultrasound findings with Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Prospective study was conducted upon 80 patients (56 F, 24 M; mean age 57 years) with primary osteoarthritis of knee joint. All patients underwent clinical assessment with calculation of WOMAC and high-resolution ultrasound of the knee joint. The ultrasound images were analyzed for cartilage thinning, osteophytes, synovial effusion, synovial proliferation, popliteal cyst, and meniscal protrusion. Image analysis was performed by two readers and linear regression analysis was used to determine association of ultrasound findings with WOMAC. There was excellent inter-observer agreement of both readers for cartilage thinning (k = 0.99, P = 0.001), osteophytes (k = 0.94, P = 0.001), synovial effusion (k = 0.98, P = 0.001), synovial thickening (k = 0.96, P = 0.001), popliteal cyst (k = 1.00, P = 0.001), and meniscal protrusion (k = 0.86, P = 0.001). There was significant association of WOMAC with cartilage changes (t = 3.406, 3.302, P = 0.001), osteophytes (t = 3.841, 3.006, P = 0.001), and synovial effusion (t = 4.140 and 2.787, P = 0.05) of both readers. We concluded that ultrasound is a reproducible method for assessment of knee osteoarthritis and well correlated with WOMAC.

Structure-symptom relationship with wide-area ultrasound scanning of knee osteoarthritis

“…Similarly, association of presence of global osteophytes with the WOMAC index and correlation of predominant morphological changes in lateral compartment including osteophytes with the KOOS symptom subscale have been reported1938. However, in the latter case, no relationship with the pain subscale was found38.…”

Pain in bilateral knee osteoarthritis – correlations between clinical examination, radiological, and ultrasonographical findings.

“…The ability of US in assessing the periarticular and intra-articular abnormalities in knee OA [18], the reliability [19], and diagnostic performance [20] of the method were already demonstrated. In the last years many studies were performed in order to establish the possible correlations between US findings and patient symptoms (especially pain) in knee OA [2,5,7,18,[21][22][23], but no clear conclusions were drawn. All the authors underlined the need for more work in this field.…”

Imaging of osteoarthritis (OA): What is new?

“…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].…”

“…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.…”

“…There are a few studies on ultrasound of menisci in the knees, showing fairly good observer reliability and agreement with MRI on meniscal damage and protrusion by both non-weightbearing and dynamic weight-bearing ultrasound examinations [66][67][68]. Although not …”