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. 2023 Jun 1;43(6):e220177. doi: 10.1148/rg.220177

Figure 7.

Imaging evaluation of patellar dislocation. (A) Merchant-view radiographs, which are obtained with the patient supine, the knee flexed to 45° at the table edge, and the tube angled downward 30°, typically with both knees in the field of view, enable evaluation of patellar alignment and symmetry. (B) Sunrise-view radiographs may be obtained with the patient prone (shown here) or supine, but for prone radiographs, they are obtained with the knee flexed to 115° and the tube angle 15° cephalad. The sunrise view is not as sensitive for assessment of patellar maltracking, but it allows better visualization of the inferior patellofemoral joint.

Imaging evaluation of patellar dislocation. (A) Merchant-view radiographs, which are obtained with the patient supine, the knee flexed to 45° at the table edge, and the tube angled downward 30°, typically with both knees in the field of view, enable evaluation of patellar alignment and symmetry. (B) Sunrise-view radiographs may be obtained with the patient prone (shown here) or supine, but for prone radiographs, they are obtained with the knee flexed to 115° and the tube angle 15° cephalad. The sunrise view is not as sensitive for assessment of patellar maltracking, but it allows better visualization of the inferior patellofemoral joint.