Abstract: The cup (2) made of a titanium-aluminum alloy is set into the acetabulum. It is thicker on one side (7) than on the opposite side (8). An aperture (17) extends from a center opening (5) of the cup to the rim (20) thereof. At the point of transition of the edges (18, 19) of the aperture to the rim, there are niches (21, 22) for the placement of pincers. This makes it possible to remove a defective insert (11) without damaging the cup or the bone. The cup is provided at its bottom rim with an encircling flange (9) intended to fit into a matching groove (10) of the insert. The cup and the insert come in contact only in this area, thus ensuring optimum introduction of force from the ball head (13) via the insert into the cup.