The 3D ACT Column Buttress & Shim are mainly used for reconstruction of open bone defects around the acetabulum. When the host bone is unable to provide sufficient stability for the hemispherical acetabulum, 3D ACT Column Buttress & Shim can be used to reconstruct the superior，anterior，posterior support points of the acetabulum. 3D ACT Column Buttress & Shim are fixed to the host bone by screws, while the corresponding surfaces between Buttress & Shim and acetabular cup are connected by bone cement.