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US 5,702,476 AGranted
Artificial joint shell
AssigneesSulzer Medizinaltechnik AG, Allo Pro AG
InventorsUrs Limacher, Stefan Lamprecht
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AssigneesSulzer Medizinaltechnik AG, Allo Pro AG
InventorsUrs Limacher, Stefan Lamprecht
Estimating the term…
The invention relates to an artificial joint shell having an outer shell (2) which is implantable in a bone base and a retro-fittable inner shell (3), the inner and outer shells being fixable to one another via a friction-locked clamping force (5), preferably via a self-locking, conical connection. A tunnel (6) is formed in the partition surface (4) between the two shells (2, 3) and connects two points at the shell edge in an arc (37) that extends towards the shell base (7). A wire (8) is threaded through the tunnel (6), and by applying an extraction force to the wire the inner shell (3) is extracted. The extraction force is uniformly applied to the inner insert along the arc (37) prescribed by the tunnel and does not damage the inner shell.
A replaceable acetabular joint implant comprising an outer shell having a cavity and an inner shell disposed in the cavity, the shells defining an interface between them and a releasable lock which releasably retains the inner shell in the cavity of the outer shell, the outer shell and the inner shell terminating in generally concentric end faces, and a tunnel formed along the interface extending from a first tunnel opening to a second tunnel opening, the tunnel openings being located at at least one of the end faces so that the tunnel is accessible past one of the openings from an exterior of the shells and a flexible tensioning member disposed in said tunnel such that the lock can be released by applying an inner shell releasing force thereto.
In a system for replacing an inner shell of an acetabular joint implant, the implant including an outer shell adapted to be anchored in body tissue and defining a cavity, the inner shell being disposed in the cavity and a lock releasably securing the inner shell to the outer shell when the inner shell is disposed in the cavity and permitting release of the inner shell from the outer shell when a force is applied to the inner shell in a direction away from the outer shell, the improvement comprising a tunnel formed along an interface between the inner shell and the outer shell when the inner shell is in the cavity, the shells defining generally concentric end faces and the tunnel terminating in spaced-apart tunnel openings accessible past the end faces from an exterior of the shells, a flexible tensioning member disposed in the tunnel, having a portion extending through at least one tunnel opening, and being connected with the inner shell, and an extractor having a gripper for gripping the extending portion of the flexible member, a base supporting the gripper and adapted to be placed into force-transmitting contact with the outer shell, and a movement mechanism adapted to apply a force to and move the flexible member with the gripper in a direction generally away from the outer shell to thereby release the lock for removal of the inner shell from the cavity of the outer shell.
Dependencies are inferred from the claim text.