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US5425733A Expired / Lapsed US ⏱️ 0.0 years remaining

Interference screw with rounded back end and cannulated sheath for endosteal fixation of ligaments

Assignee: Arthrex Inc
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Filing: 1993-06-04
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Granted: 1995-06-20
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Expires: 2013-06-04
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Abstract

Abstract An interference screw and sheath for endosteal fixation of ligaments. A graft, attached between previously cut bone blocks, is placed under tension in a graft tunnel. The screw is driven between the bone to which the graft is being fixed and a corresponding one of the bone blocks. The screw includes an end portion having rounded back edges for protecting the graft from inadvertent damage after the sheath has been removed. The screw may be cannulated for insertion over a prepositioned guide pin. The guide pin has a larger than normal diameter to prevent the pin from bending during insertion. The screw cannulation is sufficiently large to accommodate the enlarged guide pin. The sheath has a cutout at one end such that during screw insertion, the graft is covered by the sheath and protected from the threads of the screw, while the bone to which the graft is being fixed is exposed to the threads of the screw.

Inventors

  • 👤 Reinhold Schmieding

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-22 22:58
CPC Classifications
A; A61; A61B; A61B17/00; A61B17/56; A61B17/58; A61B17/68; A61B17/84; A61B17/86; A61B17/8645; A61B17/88; A61B17/8875; A61F; A61F2/00; A61F2/02; A61F2/08; A61F2/0811; A61B17/8605; A61B17/861; A61F2/0805; A61F2002/0847; A61F2002/0858; A61F2002/087; A61F2002/0876; A61F2002/0882; Y; Y10; Y10S; Y10S606/00; Y10S606/907; Y10S606/916

Claims Analysis

Total Claims: 13
Claim 1
Independent Claim 129 words
An apparatus for endosteal fixation of a substitute ligament graft by screw insertion, comprising: an interference screw having a front end and a back end, said back end having a semi-spherical shape and including means for preventing inadvertent damage to the graft comprising a rounded and smooth, unthreaded surface; and a removable cylindrical cannulated sheath for receiving said interference screw, said sheath having a proximal end and a distal end, said proximal end of said sheath having a cutout portion and a covered portion, said covered portion preventing threads of said interference screw from damaging said graft during screw insertion, and said cutout portion exposing a portion of said interference screw to permit said threads of said interference screw to cut into a bone tunnel wall during screw insertion.
Claim 2
Independent Claim 129 words
An apparatus for endosteal fixation of a substitute ligament graft by screw insertion, comprising: an interference screw having a front end and a back end, said back end having a semi-spherical shape and including means for preventing inadvertent damage to the graft comprising a rounded and smooth, unthreaded surface; and a removable cylindrical cannulated sheath for receiving said interference screw, said sheath having a proximal end and a distal end, said proximal end of said sheath having a cutout portion and a covered portion, said covered portion preventing threads of said interference screw from damaging said graft during screw insertion, and said cutout portion exposing a portion of said interference screw to permit said threads of said interference screw to cut into a bone tunnel wall during screw insertion.
Claim 3
Dependent Claim 16 words
An apparatus according to claim 1, wherein said front end of said interference screw is tapered.
Claim 4
Dependent Claim 20 words
An apparatus according to claim 1, wherein said rounded back end has an inverse hex-head for receiving a hex-head screwdriver.
Claim 5
Dependent Claim 17 words
An apparatus according to claim 1, wherein said interference screw is cannulated for receiving a guide pin.
Claim 6
Dependent Claim 22 words
An apparatus of claim 4, wherein said cannulation is sufficiently large to receive a guide pin having a diameter of 2 mm.
Claim 7
Dependent Claim 14 words
An apparatus according to claim 1, wherein said interference screw is made of titanium.
Claim 8
Independent Claim 144 words
A method of endosteal fixation of a graft by screw insertion, comprising the steps of: drilling a graft tunnel through adjacent first and second bone masses; extending a graft attached between previously cut bone blocks under tension in said graft tunnel between said adjacent bone masses; positioning a cannulated sheath between said graft and said first bone mass, said cannulated sheath having a cutout at one end, said sheath being positioned such that said graft is covered by said sheath and said first bone mass is exposed by said sheath; inserting an interference screw in the cannula of said cannulated sheath, said interference screw having a rounded back end with a semi-spherical shape and a smooth, unthreaded surface; driving said interference screw between said first bone mass exposed by said cutout and a corresponding one of said bone blocks; and removing said cannulated sheath.
Claim 9
Independent Claim 144 words
A method of endosteal fixation of a graft by screw insertion, comprising the steps of: drilling a graft tunnel through adjacent first and second bone masses; extending a graft attached between previously cut bone blocks under tension in said graft tunnel between said adjacent bone masses; positioning a cannulated sheath between said graft and said first bone mass, said cannulated sheath having a cutout at one end, said sheath being positioned such that said graft is covered by said sheath and said first bone mass is exposed by said sheath; inserting an interference screw in the cannula of said cannulated sheath, said interference screw having a rounded back end with a semi-spherical shape and a smooth, unthreaded surface; driving said interference screw between said first bone mass exposed by said cutout and a corresponding one of said bone blocks; and removing said cannulated sheath.
Claim 10
Independent Claim 184 words
A method of endosteal fixation of a graft by screw insertion, comprising the steps of: drilling a graft tunnel through adjacent first and second bone masses; extending a graft attached between previously cut bone blocks under tension in said graft tunnel between said adjacent bone masses; positioning a guide pin between said graft tunnel at said first bone mass and a corresponding one of said bone blocks; placing a cannulated sheath over said guide pin, said guide pin guiding said sheath to a position between said graft and said first bone mass, said sheath having a cutout at one end, said sheath being positioned such that said graft is covered by said sheath and said first bone mass is exposed by said cutout; placing a cannulated interference screw over said guide pin, said interference screw having a rounded back end with a semi-spherical shape and a smooth, unthreaded surface, said guide pin guiding said screw as it is inserted through the graft tunnel; and driving said cannulated interference screw between said first bone mass and said corresponding bone block; and removing said cannulated sheath.
Claim 11
Independent Claim 184 words
A method of endosteal fixation of a graft by screw insertion, comprising the steps of: drilling a graft tunnel through adjacent first and second bone masses; extending a graft attached between previously cut bone blocks under tension in said graft tunnel between said adjacent bone masses; positioning a guide pin between said graft tunnel at said first bone mass and a corresponding one of said bone blocks; placing a cannulated sheath over said guide pin, said guide pin guiding said sheath to a position between said graft and said first bone mass, said sheath having a cutout at one end, said sheath being positioned such that said graft is covered by said sheath and said first bone mass is exposed by said cutout; placing a cannulated interference screw over said guide pin, said interference screw having a rounded back end with a semi-spherical shape and a smooth, unthreaded surface, said guide pin guiding said screw as it is inserted through the graft tunnel; and driving said cannulated interference screw between said first bone mass and said corresponding bone block; and removing said cannulated sheath.
Claim 12
Dependent Claim 32 words
A method according to claim 8, wherein said cannulated interference screw has an inverse hex-head for receiving a cannulated hex-head screwdriver, said cannulated interference screw being driven by said cannulated hex-head screwdriver.
Claim 13
Dependent Claim 27 words
An apparatus according to claim 1, wherein said interference screw has a cannulation sufficiently large to receive a guide pin having a diameter of approximately 2 mm.

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1998-06-19 1998-12-19 1999-06-20 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2002-06-19 2002-12-19 2003-06-20 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2006-06-19 2006-12-19 2007-06-20 $7700.00 Window Closed / Lapsed

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