Ratcheting compression device

• US 6,004,327 A
• Filed: 06/30/1997
• Issued: 12/21/1999
• Est. Priority Date: 08/03/1993
• Status: Expired due to Term

• Current Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Original Assignee: Stryker Technologies Corporation (Stryker Corporation)
• Inventors: Crombie, John Stephen, Asnis, Stanley Edwin
• Primary Examiner(s): Buiz, Michael
• Assistant Examiner(s): Trinh, Vikki
• Application Number:
  US08/885,235
• Time in Patent Office: 904 Days
• Field of Search: 606/60-62, 606/65, 606/67, 606/72-73, 606/75, 606/105, 411/332, 411/372, 411/383-384, 411/388, 411/396
• US Class Current: 606/104
• CPC Class Codes: A61B 17/86 Pins or screws or threaded wires; nuts therefor A61B17/72 take precedence
• CPC Class Codes: A61B 17/8869 Tensioning devices

Abstract

A ratcheting compression device is provided which is very strong, which can be customized in length, which can be retightened periodically to maintain compression, which allows precise placement and alignment of bones with both grossly tuned compression and finely tuned compression, and in which only a limited inventory of parts is required. The two-piece compression device comprises (a) a novel first piece having a bone screw located at a first end thereof and having a ratcheting means located near the second end thereof and comprising teeth having their crests lying substantially in a plane and (b) a novel second piece comprising an anti-rotation means which acts in cooperation with the ratcheting means of the first piece to compress two segments of bone together.

In yet other embodiments, two embodiments of a driver are provided for quickly driving the stop onto the ratcheting means to a desired extent.

In a further embodiment, a customized method for compressing and fixing a first bone segment and a second bone segment together is provided.

Claims

1. An implant for compressing a first bone segment and a second bone segment together, said implant comprising:

(a) an antirotation element having a D-shaped bore; and

(b) a first elongated piece in the shape of a rod and having a first end and a second end and having a solid inner core throughout said entire first elongated piece and having a D-Shaped cross-section along a portion of said first piece between said first and second ends to be used in cooperation with said antirotation element and comprising;

(1) a screw threading located at least substantially adjacent to said first end and

(2) a ratchet portion having a D-Shaped cross-section extending from adjacent said screw thread toward said second end and having a smooth, flat longitudinal surface forming the flat surface of said substantially D-shaped cross-section and further comprising teeth extending across a curved surface of said D-shaped portion which are positioned near said second end and having their crests lying substantially in a plane.

2. An implant for compressing a first bone segment and a second bone segment together, said implant comprising:

(a) an elongated piece having a bone screw portion adjacent one end and a D-shaped ratchet portion adjacent said bone screw portion extending towards said second end and

(b) an antirotation element having a D-shaped bore for use in cooperation with said elongated piece, wherein said antirotation element is to be ratcheted down along said ratchet portion having a smooth, flat longitudinal surface forming the flat portion of said substantially D-shaped ratchet portion, located on said elongated piece so as to compress said first bone segment and said second bone segment together and wherein said stop has a lock component comprising a flexible interference lip which locks with teeth of said ratchet portion in a manner such that said stop can be moved only in one direction with respect to said ratchet portion of said elongated piece said stop is locked rotationally with respect to said elongated piece by the engagement of said D-shaped bore and said D-shaped ratchet portion.

3. An implant according to claim 2, wherein said first elongated piece has a solid inner core, a centerline I and a flat surface, and wherein teeth sand of said ratchet portion are positioned substantially opposite to said flat surface.

4. An implant for compressing together two segments of a bone, said implant comprising a pin having:

a longitudinal pin axis and a first end and a second end;

a bone thread located at said first end of said pin;

a smooth segment located at said second end of said pin; and

a ratchet segment having a portion with a substantially D-shaped cross-segment and having a smooth, flat longitudinal surface forming the flat of said D-shaped cross-segment and a rounded surface forming a curved part of said D-shaped cross-segment said portion located between said bone thread at said first end and said second end and starting adjacent said bone thread

and said portion having notched teeth notched into said curved of part of said D-shaped cross-section, with each of said notched teeth having a first surface which is cut perpendicular to said flat surface and a second surface which is cut at an acute angle with respect to said flat surface, wherein said first surface and said second surface meet at a meeting line, and wherein said meeting line of each of said notched teeth lies in a plane P which is parallel to said flat surface of said D-shaped cross-section.

5. The implant of claim 4 further comprising an antirotation member sized and configured to cooperate with the ratchet segment, the antirotation member having a lock component which locks with teeth of the ratchet segment so that the antirotation member can be moved only in one direction and is rotationally locked with respect to the ratchet segment.