Evaluation of patella position based on radiologic and ultrasonographic examination: comparison of the diagnostic value.

This study compared radiologic and ultrasonographic methods of evaluation of patella position. The radiologic examination was based on the evaluation of Insall and Salvati's index (I-S index), whereas the ultrasonographic examination was based on the determination of analogous coefficient called the patellar tendon-patellar coefficient (T-P coefficient). The total number of examined knee joints was 55 in 30 patients (13 children, aged 7-16 years and 17 adults aged 17-39 years) with knee pain. Considerable differences of the evaluated parameters were observed in the group of examined children: I-S index, 1.50; T-P coefficient, 1.20; and small differences in the group of adults: 1.17 and 1.32, respectively. Those differences resulted from difficulties with interpretation of the apparent radiologic picture of the knee joint with the patella incompletely ossified. The ultrasonographic picture in both children and adults is a real picture, and the possibilities of its interpretation are independent of the degree of patellar ossification.