| 摘要 |
The present invention is an acetabular cup having polyaxial locking screws for anchoring the cup in the desired bone site. The assembly includes an acetabular cup having axially tapered holes, into which holes coupling elements and bone screws may be inserted. The coupling elements each have an axial taper which matches the taper of the corresponding hole, and an interior semi-spherical concave surface in which the semi-spherical head of a corresponding bone screw may be polyaxially mounted. The bone screws are inserted through the holes until the coupling elements fully seat in the respective holes, thereby locking the screws in place and the coupling elements in the holes. In a preferred embodiment, the upper part of the holes further include annularly recessed channels in each of which a snap-ring is disposed. During the insertion of the bone screw, the advancing of the coupling element into the hole causes the snap-ring to expand. Once the coupling element is fully seated in the hole, the snap-ring contracts to its undeflected position and prevents the coupling element and screw from backing out of the hole in the event of loosening.
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