Patellar position in weight-bearing radiographs compared with non-weight-bearing: significance for the detection of osteoarthritis:

BackgroundDiagnosis and treatment of patellofemoral disorders including osteoarthritis are currently often based on imaging and clinical assessment with patients in the supine position.PurposeTo evaluate differences in patellar position in the trochlear groove and to assess the detection of medial and lateral patellofemoral (PF) osteoarthritis (OA) on axial radiographs in supine and standing positions, respectively.Material and MethodsThirty-five women and 23 men (mean age, 56 years; age range, 18–87 years) referred for routine radiographic examinations of the knees were included. Axial radiographs of the PF joint in both supine non-weight-bearing and standing weight-bearing position in 30° knee flexion were obtained of 111 knees. Measurements performed on the radiographs: patellar tilt, patellar displacement, joint space width, and grade of OA according to Ahlback.ResultsFrom supine to standing position the patella moved medially and medial joint space width and lateral patellar tilt angle decreased (P <...