| 摘要 |
The insert is made from a synthetic, biocompatible and radio-transparent material and has an anti-slip circular rim (4) which extends around a central cavity (2). The rim incorporates radio-opaque elements (6) for alignment of the insert, made e.g. from biocompatible metals such as titanium or stainless steel in the shape of short cylinders in radial holes in the edge of the rim, or balls set in spherical recesses. The radial width (e) of the anti-slip rim is at least twice the length of the radio-opaque markers, and preferably equivalent to three times their length. |
