US 5,330,535 AGranted

Screw-nut for screwing implants together

AssigneesSulzer Brothers Limited, Protek AG

InventorsWalter Moser, Roland Willi

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Abstract

A screw-nut for screwing implants together includes a thrust-shoulder which projects radially and presses axially against part of a housing. The screw-nut further includes an internal threaded portion adapted to fit a corresponding screw part, and a plurality of members, each mounted onto the side of the thrust-shoulder facing away from the part of the housing against which the thrust shoulder presses. These members are adapted to receive a tool for tightening the screw-nut. A plurality of leaf springs is included for engaging the housing part. The leaf springs, the ends of which form latching-in dogs, project, in the axial direction, from the screw-nut. The leaf springs are constructed such that, when the thrust-shoulder makes contact with the housing part, each latching-in dog snaps into a recess in the housing part in order to prevent loosening of the screw-nut from the housing part.

Claims6

Dependent claims

An implant comprising:

a tibia plate which, when in an operative position, settles on a resected tibia bone to form a platform for an artificial knee, the tibia plate including a stem receiving recess;
a stem projecting into the stem receiving recess of the tibia plate, wherein the stem is connected to the tibia plate for enhancing side-hold and for preventing withdrawal of the tibia plate, wherein:
a portion of the stem which, when in the operative position, contacts a lower plane of the tibia plate, consists of a cone with a small half angle which fits into a cylindrical bore in the tibia plate, the cylindrical bore including a rounded corner to produce line contact between the stem and the lower plane of the tibia plate;
and wherein a clearance exists between the cylindrical bore and the projecting stem in the direction of an upper plane of the tibia plate, the clearance being sized to allow the tibia plate to be substantially inclined out of a position perpendicular to the stem axis towards the stem axis;
the implant further including a screw-nut inserted from the top of the plate to press against a shoulder of the plate in an upper plane of the tibia plate and fixing the stem in the operative position while allowing the inclination of the tibia plate toward or away from the stem axis.

2 more elements

Dependencies are inferred from the claim text.