Abstract: This paper discussed the diagnostic value of musculoskeletal ultrasound (MSUS) in the knee joint synovitis and its relationship with disease severity. A total of 86 patients (112 knees) with suspected knee synovitis were selected, the differences of X-ray and MSUS in the diagnosis of knee synovitis were compared, and the relationship between semi quantitative analysis of MSUS and Lysholm score, Ayral score was analyzed. Through arthroscopy, 43 knees of 33 patients were diagnosed as synovitis, and 69 knees of 53 patients had no synovial lesions. The sensitivity, accuracy and negative predictive value of MSUS in the diagnosis of knee synovitis were significantly higher than those of X-ray (P<0.05). There was no significant difference in specificity and positive predictive value between MSUS and X-ray in the diagnosis of knee synovitis (P>0.05). The blood flow signals, synovial hyperplasia, joint effusion and bone erosion Ⅱ level and above proportion of knee with Lysholm score ≥ 70 points were significantly higher than those of Lysholm score<70 knee (P<0.05). The blood flow signals, synovial hyperplasia, joint effusion and bone erosion Ⅱ level and above proportion of knee with Ayral score ≥ 60 points were significantly higher than the knee with Ayral score < 60 (P<0.05). The Lysholm score was positively correlated with MSUS score of synovial hyperplasia and bone erosion (r_s=0.714 and 0.741, P<0.05). Ayral score was positively correlated with MSUS synovial hyperplasia (r_s=0.613, P<0.05). MSUS has a good value in the diagnosis of knee synovitis, and the semi quantitative classification of MSUS is related to the function of knee joint and the degree of synovium.

Key words: musculoskeletal ultrasound, knee synovitis, diagnostic value, severity