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US5593410A Expired / Lapsed US ⏱️ 0.0 years remaining

Screw device for fixing prostheses to bones

Assignee: Individual
•
Filing: 1993-03-02
•
Granted: 1997-01-14
•
Expires: 2013-03-02
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Abstract

Abstract In a screw device (10; 80) for fixing prostheses to bones, the threaded shank (14) comprises a core (32, 34) of overall frustoconical shape. The screw has a cylindrical neck (12) of diameter equal to or greater than the maximum diameter of the thread. This latter is of two different types, namely a first thread (26) of large pitch for fixing into the trabecular bone tissue (52) and a second thread (28), which can be of the self-tapping type, for fixing into tile cortical bone opposite the point at which the screw is inserted into the bone. The second thread (28) has a number of starts which is a multiple of that of the first thread (26). For orthopedic use the screw (80) can comprise a third thread (128) on a part of the neck (112) for fixing into the relative cortical bone (50). A method for applying the screw device (10; 80) consists of forming a precision hole (40) in the bone, tapping said hole with a tapper (60; 100), and screwing the screw (10; 80) into it. The precision hole (40) is obtained by using a cutter (100) in the shape of an inverted "wedding cake", then reaming the obtained cavity with a manual reamer (140).

Inventors

  • 👤 Giuseppe Vrespa

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-23 11:56
CPC Classifications
A; A61; A61C; A61C8/00; A61C8/0018; A61C8/0022; A61C8/0025; A61B; A61B17/00; A61B17/56; A61B17/58; A61B17/68; A61B17/84; A61B17/86; A61B17/8625; A61B17/863; A61C8/0089

Claims Analysis

Total Claims: 11
Claim 1
Independent Claim 126 words
A screw device for fixing a prosthesis to a bone, the device comprising: a substantially cylindrical neck having a diameter; and a shank having a core of generally frusto-conical shape and thread on the core, the thread having a diameter equal to or less than the diameter of the neck, the thread comprising a first thread portion of large pitch, and having a number of starts the first thread portion being suitable for fixing to trabecular bone tissue and a separate second thread portion of smaller pitch adjacent the first thread portion and suitable for fixing into a cortical part of the bone, the second thread portion having a number of starts which is a multiple of the number of starts on the first thread portion.
Claim 2
Dependent Claim 126 words
A screw device for fixing a prosthesis to a bone, the device comprising: a substantially cylindrical neck having a diameter; and a shank having a core of generally frusto-conical shape and thread on the core, the thread having a diameter equal to or less than the diameter of the neck, the thread comprising a first thread portion of large pitch, and having a number of starts the first thread portion being suitable for fixing to trabecular bone tissue and a separate second thread portion of smaller pitch adjacent the first thread portion and suitable for fixing into a cortical part of the bone, the second thread portion having a number of starts which is a multiple of the number of starts on the first thread portion.
Claim 3
Dependent Claim 18 words
A screw device as claimed in claim 1 wherein the second thread portion of the shank is self-tapping.
Claim 4
Dependent Claim 28 words
A screw device as claimed in claim 1 wherein the first thread portion is of substantially trapezoidal cross-section and the second thread portion is of substantially triangular cross-section.
Claim 5
Dependent Claim 20 words
A screw device as claimed in claim 1 wherein the first thread portion has an outer diameter which is constant.
Claim 6
Dependent Claim 29 words
A screw device as claimed in claim 1 wherein the second thread portion has three times as many starts as the number of starts on the first thread portion.
Claim 7
Dependent Claim 26 words
A screw device as claimed in claim 1 wherein the first thread portion is a single-start thread, and the second thread portion is a three-start thread.
Claim 8
Dependent Claim 24 words
A screw device as claimed in claim 1 wherein the neck has a surface which comprises a third thread portion which is self-tapping type.
Claim 9
Dependent Claim 24 words
A screw device as claimed in claim 1 wherein the neck has an end including a first hole therein for receiving a prosthetic pin.
Claim 10
Dependent Claim 35 words
A screw device as claimed in claim 8 wherein the neck has a cavity therein substantially coaxial with the hole, the cavity receiving a tool to facilitate fixing of the screw device to the bone.
Claim 11
Dependent Claim 29 words
A screw device as claimed in claim 1 wherein the neck has a cavity therein for receiving a tool to facilitate fixing of the screw device to the bone.

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USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 2000-01-14 2000-07-15 2001-01-14 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2004-01-14 2004-07-15 2005-01-14 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2008-01-14 2008-07-15 2009-01-14 $7700.00 Window Closed / Lapsed

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