a randomized controlled study evaluating modified cup anteversion placement in prevention of postoperative dislocation in patients undergoing acetabular tumor resection and reconstruction

Conditions: Periacetabular Tumor

Summary: 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

hip dislocation is a common complication in patients who undergo reconstruction surgery after periacetabular tumor resection and most of these cases are anterior dislocations. studies suggest that this type of dislocation may be closely related to the position and anteversion angle of the acetabular component. therefore, properly reducing the anteversion angle of the acetabular cup during reconstruction might effectively prevent possible collisions between the cup and the femoral component, thereby reducing the potential risk of dislocation. based on this theory, we aim 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. 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 size. a standard error within 10° is accepted.

Eligibility criteria:
inclusion criteria: * age above 16 years old, gender is not limited. * tumor involving periacetabulum, femoral head, femoral neck or proximal femur * patients require 3d-printed hemipelvic endoprosthetic reconstruction following periacetabular tumor resection * the subject has an estimated survival period of at least one year or more. * the subjects with informed consent exclusion criteria: * the patient used to conduct surgery on his/her hip joint * the patient's current surgery aimed for hip revision for implant failure or infection * the patient didn't conduct hip endoprosthetic reconstruction * patients with congenital defects in the gluteal muscle group, neurological function or pelvic tilt deformity severe enough to affect functional activity * patients cannot self-assess postoperative function after surgery * according to the judgment of the investigator/supervisor, there may be difficulties in completing postoperative follow-up * subjects have participated in similar research projects

Keywords: dislocation, endoprosthetic reconstruction, anteversion angle, pelvis