Orthopedic fixation device with bioresorbable layer
OwnerDouglas Cerynik, Susan P. Hardinginventors
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Abstract
An orthopedic screw is used in a fixation device for treating fractures. The device has a body with holes to accept the bone screws. The bone screws have a layer of bioresorbable material on the shaft. Engagement between the bone screws and the body is initially through the bioresorbable material, which engagement rigidly fixes the relative angular orientation between the bone screws and the body when the device is applied to a bone. As the bioresrobable material is resorbed the angular relation between the bone screws and the body is no longer rigidly fixed, thereby effecting a transformation from rigid osteosynthesis to flexible osteosynthesis to allow micromotion between the bone fragments which promotes healing.
Claims33
An orthopedic screw for use with a fixation device connecting a first bone portion to a second bone portion, said fixation device including a body for linking said first bone portion to said second bone portion, said body having a plurality of holes extending therethrough, said screw being insertable though at least one of said holes extending through said body, said screw comprising:
- a shaft having a distal end and an oppositely disposed proximal end;
- external helical screw threads extending along at least a first portion of said shaft;
- a head attached to said proximal end of said shaft;
- and
- a layer of bioresorbable material positioned surrounding a second portion of said shaft and rotationally fixedly attached thereto to prevent relative rotation between said shaft and said layer of bioresorbable material, said layer of bioresorbable material having an outer surface engageable with said body to initially fix said screw at a desired angular position relatively to said body, said screw being angularly movable with respect to said body upon resorbtion of at least a portion of said bioresorbable layer.
Dependencies are inferred from the claim text.