CT image acquisition
All patients underwent preoperative CT scans of bilateral hips, with images acquired from the PACS system in DICOM format. CT scans were performed using a Brilliance CT scanner (128-row, Philips Healthcare, Netherlands) or a LightSpeed VCT scanner (64-row, GE Healthcare, USA), with scan parameters including tube voltage of 120-140 kV, tube current of 220-680 mA, exposure time of 250–800 mS, layer thickness of 1.0–3.0 mm, layer spacing of 1.0–3.0 mm, and matrix sizes of 512 × 512.The resampling process was carried out using the bilinear interpolation method, with the resampling layer thickness and layer spacing set at 1 mm. Images were then imported into 3D Slicer (