Fig. 2

Loads and Constraints: a Simulated pelvic ring stress in three positions: a1 bilateral standing, a2 single-leg standing, and a3 sitting after acetabular tumor resection and reconstruction. b Arrows represent the vertical stress applied to the sacrum, simulating 2/3 of the body weight, depicting different mechanical characteristics of the pelvic ring under different conditions. Green circles (purple circles) indicate the constrained regions at the acetabulum (ischial tuberosity). Yellow lines represent spring elements simulating the interaction between the pelvic region and lower limb muscles (accounting for muscle attachment points). c Muscle load illustration and mesh display in the 3D printing and modular groups: Demonstrating muscle load distribution in three types of pelvic defect reconstructions. Mesh representation shows the 3D printing and modular prosthetic components in place. d FEA results of stress and displacement distribution in a normal pelvic ring