All included patients were examined using the Philips Achieva 1.5-T MRI system (Philips Medical Systems). The patient was in supine position, with the knee in extended position at 10° of flexion, and the lower limb slightly external. The sagittal, coronal and axial sequences with a spin echo T1-weighted image (T1WI), a gradient echo sequence T2 weighted image (T2WI), and a fast spin echo pressure lip sequence, were performed routinely in the protocol. Slice thickness was 3 mm for each plane with a gap of 0.6 mm. The matrix size was 224 × 352 pixels, and the field of view was 16 cm.
True or nearly true lateral radiographs with the overlap between the posterior halves of the medial and lateral condyles were taken at 30° of knee flexion, which included the lateral surface of the patella, and at least the area between half of the femoral shaft and half of the tibial shaft.
True or nearly true lateral radiographs with the overlap between the posterior halves of the medial and lateral condyles were taken at 30° of knee flexion, which included the lateral surface of the patella, and at least the area between half of the femoral shaft and half of the tibial shaft.