Fig. 2

Utilization of 3 dimensional-printed PSI, A. Acetabular parts of PSI; B. Insertion of the fitting guide to locate the designed position and direction, with additional parts assembled following the Lego principle, and two pins secured through designated holes; C. Removal of the fitting guide, with the reaming direction aligned parallel to the pins, as indicated by the yellow arrow; D. Femoral components of PSI; E, F. The resection guide was anchored with 2 pins, and both the level and direction of resection were established by the resection guide, denoted by the yellow line