| 摘要 |
A tibial prosthesis is described comprising a metal tray component (1) comprising a transverse member (3) having an upper side with a peripheral upstanding rim (6) and a lower side provided with a projecting stem (4) for insertion in a surgically prepared cavity in a tibia of a patient. The upstanding rim (6) includes a posterior rim portion and an anterior rim portion. The posterior rim portion is provided with an undercut lip forming a pair of recesses (7, 8) and the anterior rim portion has an open angled posterior surface portion (9) and a posteriorly projecting barbed portion (10). The prosthesis also includes a tibia insert (2) made of a plastics material shaped to fit on the upper side of the tibial implant (1) within the upstanding rim (6) and having an upper bearing surface (11, 12) adapted to cooperate with at least one condyle of a femur or of a femoral implant and a lower surface. The tibia insert (2) further has on a posterior portion thereof a shaped contour (14, 15) adapted in use to fit snugly under the undercut lip and on an anterior portion thereof an anterior surface (13) having a taper angle substantially corresponding to the angle of the open angled posterior surface portion. In use, a surgeon can insert the tibia insert (2) in the metal tray component (1) by first locating the shaped contour (14, 15) in a recess (7, 8) under the undercut lip and then pressing on the upper bearing surface (11, 12) to force the anterior surface (13) into engagement with the open angled posterior surface portion and to cause interfacing with the barbed portion (10) so as to lock the tibia insert (2) to the metal tray component (1) and to minimise translational micromotion.
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