Locking screw system with relatively hard spiked polyaxial bushing
US8388666B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 27, 2007 |
| Grant date | Mar 5, 2013 |
| Priority date | — |
| Expiry date | Feb 25, 2030 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B17/8057
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A polyaxial locking screw system includes a bone plate defining a plate hole with an inner spherical surface and a relatively harder split polyaxial bushing with a outer spherical surface provided within the plate hole for receiving a bone screw. In one embodiment, the plate is formed from titanium alloy, while the bushing is formed from a cobalt chrome alloy. The outer surface of the polyaxial bushing includes a plurality of spikes. When the screw is inserted into the bushing, since the bushing material is considerably harder than the plate material, the forceful expansion of the bushing during screw insertion causes the spikes to penetrate into the inner spherical surface of the hole, thereby increasing the frictional engagement of the bushing to the plate to lock the screw at a desired angle.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.