A Randomized Controlled Study Evaluating Modified Cup Anteversion Placement in Prevention of Postoperative Dislocation in Patients Undergoing Acetabular Tumor Resection and Reconstruction

The purpose of this clinical study is to investigate whether patients who receive modified anteversion angle (( α-15°)±10°) of the acetabular cup have a lower risk of dislocation within one year after surgery, compared to patients who receive conventional anteversion angle ( α±10°) of the acetabular cup. The hypothesis is that patients with placement of the modified (( α-15°)±10°) anteversion angle of the acetabular component will have decreased risk of dislocation 1 year after surgery compared to patients with conventional anteversion angle ( α±10°) placement. PS: α refers to the preoperative anteversion angle of the affected hip. α equals to the anteversion angle of the contralateral limb if it cannot be accurately measured on the affected limb. A standard error within 10° is accepted