Ultrasound in the evaluation of the knee and patellar regions.

Studies were carried out in 25 patients (mean age, 34.2 years) with knee or patellar problems, using a real-time scanner. The contralateral leg, which was asymptomatic, was used as a control. Identification of the patellar bone and the area of insertion of the infrapatellar tendon was not difficult. The area of insertion was less echogenic than other parts of the tendon. Patchy, partial, or total ruptures could be identified using ultrasound. Sonolucent structures in cases of Baker's cyst were easily identified. The study revealed three partial suprapatellar tendon ruptures, three partial infrapatellar tendon ruptures, six old injuries of the infrapatellar tendon with fibrosis and scar tissue, one case of prepatellar bursitis, one parapatellar (cartilaginous) loose body, two intraarticular loose bodies (bony), and four cases of Baker's cyst, of which one was found to be ruptured. The differences in echogenicity of the tendons and surrounding soft tissues were more conspicuous using interposed Kiteko than with direct skin contact.