Roentgenographic Techniques by Digital Radiography and Diagnosis for Subluxation of Patella

Objective To evaluate the reliability of axial view of patella with the knee joint flexed at 60 and 90 degrees on imaging diagnosis of patellar subluxation with DR (digital radiography). Methods 60 cases confirmed patella subluxation were reviewed retrospectively. In addition to routine anteroposterior and lateral DR views, axial DR views of patella with the knee flexed at 60 degrees and 90 degrees were taken meanwhile. Results Of the 60 cases, 45 failed to provide any patellar problems, while the other 15 cases revealed suspicious imaging view of patella subluxation in their normal AP and lateral DR views. In the axial DR views of patella with the knee flexed at 60 degrees and 90 degrees, 50, 4 and 6 cases revealed subluxation, suspicious subluxation and normal alignment of patella. Conclusion Axial DR view of patella with the knee joint flexed at 60 and 90 degrees could provide helpful roentgenographic information in determining the existence of patella subluxation.