US4959064A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dynamic tension bone screw
Assignee: De Puy Inc
•
Filing: 1988-10-07
•
Granted: 1990-09-25
•
Expires: 2008-10-07
Abstract
Abstract A dynamic bone fixation screw for rejoining fracture fragments of a bone to their approximate original mutual dispositions. It includes a threaded distal end member for threaded engagement with one of the bone fragments and a head member at a proximal end for engagement with another of the bone fragments. A spring member integral with and extending between the distal end member and the head member enables a predetermined torque to be initially imparted to the bone. When stress relaxation in the bone occurs, the spring member relaxes accordingly while continuing to draw the bone fragments together. The bone screw is fabricated in a unique manner.
Inventors
- 👤 John A. Engelhardt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 00:44
CPC Classifications
B; B23; B23P; B23P13/00; A; A61; A61B; A61B17/00; A61B17/56; A61B17/58; A61B17/68; A61B17/84; A61B17/86; F; F16; F16B; F16B31/00; F16B31/04; F16B35/00; F16B35/04; F16B35/041; A61B17/869
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
159 words
A dynamic fixation screw constructed wholly from an elongated screw having a longitudinal axis for rejoining fracture fragments of a bone in their approximate original mutual dispositions comprising: a threaded distal end member for threaded engagement with one of the bone fragments; a head member at a proximal end for engagement with another of the bone fragments; and a threaded shank member of reduced outer diameter intermediate said distal end member and said head member, said elongated screw having a bore therein coaxial with said longitudinal axis extending through said head member and said shank member and having a diameter that slightly exceeds the root diameter of the threads in said threaded shank member thereby resulting in a spring member integral with said distal end member and with said head member for drawing the bone fragments together in a manner which continuously adjusts the force being applied to the bone according to the stress relaxation manifested by the bone.
Claim 2
Dependent Claim
159 words
A dynamic fixation screw constructed wholly from an elongated screw having a longitudinal axis for rejoining fracture fragments of a bone in their approximate original mutual dispositions comprising: a threaded distal end member for threaded engagement with one of the bone fragments; a head member at a proximal end for engagement with another of the bone fragments; and a threaded shank member of reduced outer diameter intermediate said distal end member and said head member, said elongated screw having a bore therein coaxial with said longitudinal axis extending through said head member and said shank member and having a diameter that slightly exceeds the root diameter of the threads in said threaded shank member thereby resulting in a spring member integral with said distal end member and with said head member for drawing the bone fragments together in a manner which continuously adjusts the force being applied to the bone according to the stress relaxation manifested by the bone.
Claim 3
Dependent Claim
33 words
A dynamic fixation screw as set forth in claim 1 wherein the outer diameters, respectively, of said distal end members and of said head members are greater than that of said spring member.
Claim 4
Dependent Claim
61 words
A dynamic fixation screw as set forth in claim 2 wherein said distal end member, said head member, and said spring member are substantially symmetrically aligned along a longitudinal axis; wherein said head member has a central bore therethrough aligned with the longitudinal axis; and wherein said distal end member has a tool receiving means for applying torque to said screw.
Claim 5
Dependent Claim
47 words
A dynamic fixation screw as set forth in claim 3 wherein said tool receiving means is an axially aligned recess having a tool receiving opening facing said head member and shaped to receive the working end of a tool for rotating said screw about its longitudinal axis.
Claim 6
Dependent Claim
31 words
A dynamic fixation screw as set forth in claim 3 wherein said tool receiving means is an axially aligned recess shaped to receive the working end of a hexagonal drive wrench.
References Cited (Backward Citations)
US972787A
Cited
US1204254A
Cited
FR560269A
Cited
US2035497A
Cited
US2037156A
Cited
US2563976A
Cited
US2856617A
Cited
US3051169A
Cited
US2985168A
Cited
US3076453A
Cited
US3053555A
Cited
US3435526A
Cited
US3554193A
Cited
SU652940A1
Cited
US4227518A
Cited
DE2808969A1
Cited
SU923533A1
Cited
SU1061807A1
Cited
US4537185A
Cited
USD283591S
Cited
US4589179A
Cited
US4711232A
Cited
US4621629A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-09-24 | 1994-03-26 | 1994-09-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-09-24 | 1998-03-26 | 1998-09-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-09-24 | 2002-03-26 | 2002-09-25 | $7700.00 | Window Closed / Lapsed |