Sonographic diagnosis of the knee effusion

This paper presents the diagnosis of effusion of the knee by ultrasound. 140 patients with pain and swelling of the knee were detected to have suprapatellar effusion by ultrasound. The antero-posterior distances of the suprapatellar effusion were 0.2-3.4 cm with a mean of 1.2 cm. The effusion was revealed as an anechoic fluid-filled area in 121 cases (86.4%), as a hypoechoic area in 15 cases (10.7%), and as a mixed anechoic fluid-filled area and hypoechoic area in remaining 4 (2.9%). Of 140 cases of knee effusion, 126 cases were verified by aspiration or operation. The results obtained demonstrate that ultrasound can visualize not only the effusion of the knee, but also the abnormalities in the menisci, synovium, and the popliteal fossa; This provides an important basis for diagnosis and treatment. Furthermore, ultrasound is painfree, noninvasive, inexpensive, readily acceptable by patients, and convenient for follow-up studies.