EP0669110A2
Expired / Lapsed
EP
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Interference screw having a double tapered root
Assignee: Smith and Nephew Inc
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Filing: 1995-02-13
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Granted: —
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Expires: 2015-02-13
Abstract
Abstract An dual tapered orthopedic fixation screw is used to anchor ligament grafts inside a bore in a bone mass. The fixation screw includes a root portion having a front section, a cylindrical center section and a back section. A screw thread is formed over substantially the entire root portion to increase purchase. A taper is formed on the back of the root portion to increase compression of the fixation screw against the ligament graft. The screw further includes a rounded portion that is formed between the taper and the back end of the root to prevent the screw from fraying or cutting the ligament. <IMAGE>
Inventors
- 👤 Randall J. Huebner
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 00:20
CPC Classifications
A; A61; A61F; A61F2/00; A61F2/02; A61F2/08; A61F2/0811; A61B; A61B17/00; A61B17/56; A61B17/58; A61B17/68; A61B17/84; A61B17/86; A61B17/8605; A61B17/8625; A61B17/863; A61B17/8645; A61F2002/0817; A61F2002/0841; A61F2002/0847; A61F2002/0858; A61F2002/087; A61F2002/0876; A61F2002/0888
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
87 words
An orthopedic fixation screw for anchoring a bone graft in a bore formed in a bone mass, said screw comprising: a root portion having a front and back end, the root portion including a center section and a back section; a screw thread formed over substantially all of the center and back sections; and a taper formed on said root back section and extending substantially entirely between said back end and said center section, said taper being larger toward the back end than toward the center section.
Claim 2
Dependent Claim
111 words
An orthopaedic interference screw for compression anchoring a bone graft in a bore formed in a bone mass, said screw comprising: a root having front and back ends and further including a center section and a back section; a screw thread formed over substantially all of the center and back sections, the screw thread including a crest with an outer surface having a width that increases at least along the back section away from the center section; and a taper formed on said root back section and extending substantially entirely between said back end and said center section, said taper being larger toward the back end than toward the center section.
Claim 3
Dependent Claim
22 words
A screw according to claim 1 wherein said screw further includes a rounded portion formed between said taper and said back end.
Claim 4
Dependent Claim
23 words
A screw according to claim 1 wherein the distance between the thread crests and the root along the center section is substantially constant.
Claim 5
Dependent Claim
34 words
A screw according to claim 4 wherein the distance between the thread crests and the root portion in the back section diminishes between the center section of the root portion and the back end.
Claim 6
Dependent Claim
37 words
A screw according to claim 5 wherein the crest height over the back root section diminishes inversely to said taper thereby maintaining a substantially uniform crest diameter along the back and middle sections of the root portion.
Claim 7
Dependent Claim
47 words
A screw according to claim 3 wherein said root portion further includes a front section having a taper formed thereon, said front section taper extending substantially entirely between said front end and said center section and being larger toward the center section than toward the front end.
Claim 8
Dependent Claim
29 words
A screw according to claim 1 wherein the crest of the screw thread includes a top face having a width that increases toward the back end of the root.
Claim 9
Dependent Claim
12 words
A screw according to claim 1 wherein the root portion is cannulated.
Claim 10
Dependent Claim
108 words
An orthopaedic interference screw for compression anchoring a bone graft in a bore formed in a bone mass, said screw comprising: a root having a front section, a center section and a back section; a screw thread formed over substantially all of the front, center and back sections, the screw thread including a crest with an outer surface having a width that increases at least along the back section away from the center section; and a taper formed on said root back section and extending substantially entirely between said back end and said center section, said taper being larger toward the back end than toward the center section.
Claim 11
Dependent Claim
17 words
A screw according to claim 10 wherein the front and back sections are substantially the same length.
Claim 12
Dependent Claim
16 words
A screw according to claim 10 wherein the taper has a slope of approximately 7 degrees.
Claim 13
Dependent Claim
46 words
A screw according to claim 10 including a channel extending longitudinally through the root from the front end to the back end, the channel having a hexagonal socket in the back section for engaging a driver and a circular cross-sectional shape-in the center and front sections.
Claim 14
Dependent Claim
19 words
A screw according to claim 10 including a rounded nose section joined to the front end of the root.
References Cited (Backward Citations)
No citation records indexed.
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