External bone fixation system
An external fixation assembly for bone fusion or separation is disclosed. The assembly includes a fracture fusion tube, with a bracket slidably engaged thereon. The assembly further includes a collet clamp connected to the bracket, with a ball collet rotatably seated within the clamp, the ball collet having an aperture for receiving a bone bin therethrough and perforations for a compression engagement with a bone pin. The assembly uses a single screw for threadably engaging the ball collet, the clamp and the bracket such that the position of the bone pin, ball collet and bracket are all fixed.
1. An external bone fixation system, comprising:
a cylindrical fracture fusion tube comprising at least one recess along its length; and
multiple bracket/clamp assemblies removably attached to the fracture fusion tube, wherein each of the bracket/clamp assemblies comprises:
only one bracket slideably mounted on the fracture fusion tube via a bracket throughbore, wherein the bracket includes a threaded bracket support aperture;
a single screw threaded through the bracket support aperture;
only one pin collet clamp fixed to the bracket via the single screw that extends through a threaded clamp support aperture of the pin collet clamp, wherein the pin collect clamp further comprises a clamp throughbore, and wherein the pin collet clamp is rotatable, relative to the bracket and before the single screw is tightened, around an axis defined by the collet clamp support aperture, the bracket support aperture, and the single screw; and
only one ball collet rotatably disposed within the clamp throughbore of the pin collet clamp and defining a ball collet aperture for receiving a bone pin, wherein the ball collet is free to rotate in multiple planes within the clamp throughbore to allow a direction of the ball collet aperture to be independently adjusted in the multiple planes;
wherein tightening the single screw simultaneously tightens the bracket over the fracture fusion tube, tightens the bracket and pin collet clamp together so that they cannot rotate relative to one another, and compresses the clamp throughbore, which thus crushes the ball collet, thus preventing the ball collet from rotating within the clamp throughbore and tightening the ball collet aperture over the bone pin.
2. The system of claim 1 , wherein the at least one recess of the fracture fusion tube is disposed between at least two of the multiple bracket/clamp assemblies to prevent the bracket/clamp assemblies from sliding past the at least one recess along the fracture fusion tube.
3. The system of claim 2 , wherein the fracture fusion tube further comprises at least two detents, wherein each of the at least one recess has a first detent located at one end of the recess and a second detent located at an opposite end of the recess, to further prevent the bracket/clamp assemblies from sliding past the at least one recess along the fracture fusion tube.
4. The system of claim 1 , wherein each of the bracket/clamp assemblies further comprises a sleeve disposed in the clamp throughbore of the pin collet clamp, wherein the ball collet is disposed in the sleeve.
5. The system of claim 4 , wherein the sleeve is made of plastic, and wherein the bracket, the pin collet clamp and the single screw are made of metal.
6. The system of claim 5 , wherein the ball collet is made of metal.
7. The system of claim 1 , wherein the pin collet clamp comprises a first surface feature on a side of the pin collet clamp, and wherein the bracket comprises a second surface feature on a side of the bracket, wherein the first surface feature and the second feature are configured to mate with one another when the side of the pin collet clamp and the side of the bracket are brought together by tightening the single screw.
8. The system of claim 1 , wherein the ball collet comprises:
a first pair of cuts extending from a first opening of the ball collet aperture over an outer surface of the ball collet toward a second opening of the ball collet aperture; and
a second pair of cuts extending from the second opening of the ball collet aperture over the outer surface of the ball collet toward the first opening of the ball collet aperture,
wherein each of the first and second pairs of cuts extends along approximately 90 percent of a length of the outer surface, and
wherein the cuts are configured to allow the ball collet to collapse when squeezed within the clamp throughbore of the pin collet clamp.
9. The system of claim 1 , wherein the multiple bracket/clamp assemblies are configured to attach to multiple bone pins extended from a bone at multiple different angles.