Ultrasound‐Based Knee Osteoarthritis Severity Assessment and Its Association With Kellgren–Lawrence Grading

Background Kellgren–Lawrence (KL) grading is a conventional radiography (CR)‐based system commonly used to assess osteoarthritis (OA). Knee OA is characterized by damage to the femoral cartilage (FC); however, CR cannot directly visualize cartilage integrity. Ultrasound (US) may be superior in detecting FC damage. This study is aimed at evaluating the US‐based knee OA severity assessment and analyze its association with KL grading. Methods This was an analytical observational study with a cross‐sectional design which included knee OA patients. All participants underwent knee US scanning by two independent raters. The severity of knee OA was assessed based on three parameters: the contour of the femoral cartilage, the presence of osteophytes, and meniscus protrusion. The results were accumulated and interpreted into grades from 0 to 4. Association between US‐based knee OA assessment and KL grading was analyzed statistically. Results A total of 112 knee OA patients were included in this study. The average age of participants was 61.4 years, with a higher female prevalence. Grade 3 was the most frequently recorded in both US and KL grades. The US interpretation from both raters showed a perfect agreement based on weighted kappa analysis ( κ = 1.00). A chi‐square test showed a significant association between the US and KL grade ( p < 0.001), with a very strong association based on the Cramér′s V test of 0.742 (95% CI: 0.599–0.824). Conclusion This study demonstrates the US‐based knee OA severity assessment and was associated with KL grade.