Comparative validation of the radiographic and tomographic measurement of patellar height.

Objective: To evaluate and validate the radiographic measurement of patellar height with computerized tomography scans.

Methods: Measured the patellar height through the lateral radiographic image supported by one foot and sagittal tomographic view of the knee in extension, flexion of 20°, and quadriceps contraction of 40 patients (80 knees), asymptomatic and no history of knee injuries using Insall-Salvati index. There were 20 adult females and 20 adult males.

Results: The height patellar index was higher in women of all images taken, in proportion. There was no statistical difference of patellar height index between the radiographics and tomographics images.

Conclusion: The Insall-Salvati index in females was higher in all cases evaluated. Furthermore, it is possible to measure the patellar height index during tomographic study without distorting the results obtained, using to define the presence of patella alta or patella baja.